OA19377A - Procédé de préparation de matériau d'origine végétale riche en acides phénoliques, comprenant au moins un métal, pour la mise en œuvre de réactions de synthèse organique. - Google Patents

Abstract

L'invention concerne un procédé de préparation d'un matériau d'origine végétale riche en acides phénoliques, comprenant au moins un métal, ledit procédé comprenant les étapes suivantes : a. une préparation d'un matériau d'origine végétale choisi parmi : ■ les plantes aquatiques ; ■ les matériaux riches en tanins ; ■ les matériaux riches en lignine ; et l'obtention d'un matériau d'origine végétal, riche en acides phénoliques, dans lequel le rapport de l'intensité de la bande de vibration de la liaison OO du groupe COOH et de l'intensité de chacune des bandes de vibration du cycle aromatique déterminées en FT-IR est compris entre 0,5 et 4. de préférence entre 1 et 3,5, par exemple entre 1 et 2,5 : b. une mise en contact du matériau d'origine végétal obtenu à l'issue de l'étape a) avec un effluent comprenant de 0,1 à 1000 mg/L d'au moins un métal, de préférence pendant une durée comprise entre 1 heure et 2 heures, à une température de préférence comprise entre 10 et 30°C ; et c. l'obtention d'un matériau d'origine végétale riche en acides phénoliques comprenant de 1 à 30 % en poids d'au moins un métal par rapport au poids total du matériau.

Description

Process for the preparation of material of plant origin rich in phenolic acids, comprising at least one metal, for carrying out an organic synthesis reaction

The present invention relates to a process for preparing a material of plant origin rich in phenolic acids and comprising at least one metal.

The present invention also provides a method of depolluting or treating an effluent comprising at least one metal by bringing a material of plant origin rich in phenolic acids into contact with said effluent.

The present invention also relates to a process for carrying out organic synthesis reactions using said material of plant origin as a catalyst.

State of the art

Human activities (quarrying, chemical, mining, metallurgical, agricultural activities, etc.) have led to the dispersion of metallic elements in aquatic systems. According to the French Water Partnership (PFE), "water is the first resource affected by climate change with all indicators in the red". European Directive 2000/60 / EC established a framework for improving water quality. This directive presents, in particular, a strategy for the control of pollution by the substances of the most concern. Metals are on the list of priority substances.

In addition, the world's mineral resources are becoming increasingly scarce. The development of green and digital technologies exert strong pressure on demand. At the current rate of production, Sb, Zn, Pb will be exhausted before 20 years, Mn, Cu, Ni before 40 years. Rare earths and PGMs are only available in a very limited number of countries.

Aims of the invention

Thus, there is a need for rapid and efficient decontamination of water polluted by metals.

There is also a need for a powerful method of environmentally friendly recycling of increasingly scarce and threatened primary and precious metals.

Finally, there is a need to transform materials of plant origin comprising at least one metal via a single recovery process, phytocatalysis (or ecocatalysis) by producing new catalytic systems capable of advantageously replacing conventional chemical catalysts.

Thus, the aim of the invention is to provide a material and / or a process capable of solving one or more of the technical problems set out in the present invention.

An objective of the present invention is to solve the technical problem consisting in providing a material and / or process for rapidly and efficiently decontaminating water polluted by metals.

An objective of the present invention is to solve the technical problem of providing a material and / or process for the ecological recycling of primary metals.

Another objective of the present invention is to provide catalysts making it possible to carry out organic synthesis reactions.

Detailed description of the invention

The present invention relates to a PI process for preparing a material of plant origin rich in phenolic acids, comprising at least one metal, said process comprising the following steps:

at. a preparation of a material of plant origin from a dead plant preferably chosen from:

aquatic plants, preferably the roots of aquatic plants such as, for example, water hyacinth or water lettuce;

materials rich in tannins such as, for example, coffee grounds or tea grounds;

- materials rich in lignin such as, for example, wheat straw, pine cones, pine bark, coconut husks; and obtaining a material of plant origin, rich in phenolic acids, in which the ratio of the intensity of the vibration band of the C = O bond of the COOH group and the intensity of each of the bands of vibration of the aromatic ring determined in FT-IR is between 0.5 and 4, preferably between 1 and 3.5, for example between 1 and 2.5;

b. contacting the material of plant origin obtained at the end of step a) with an effluent comprising from 0.1 to 1000 mg / L of at least one metal, preferably for a period of between 1 hour and 2 hours, at a temperature preferably between 10 and 30 ° C, and

vs. obtaining a material of plant origin rich in phenolic acids comprising from 1 to 30% by weight of at least one metal relative to the total weight of the material.

The roots of aquatic plants are advantageous in the process of the invention due to their polymeric structure. Aquatic plants advantageously used are water hyacinth (Eicchornia crassipes) or water lettuce (Pistia stratiotes).

For the purposes of the present invention, the term "material rich in tannins" means materials of plant origin essentially consisting of tannins. Among these materials, there may be mentioned coffee grounds and green and / or black tea leaves.

For the purposes of the present invention, the term “materials rich in lignin” is understood to mean materials of plant origin mainly comprising lignin, such as cereal straw such as wheat straw, coconut or hemp floss; fiber plants; woods of deciduous trees such as birch, chestnut, eucalyptus; waste derived from wood, in particular, for example, sawdust from poplar, agave, pine, in particular pine bark, or sorghum, cones of conifers such as pine cones, bugs such as those of chestnuts.

Quite surprisingly, it has been discovered that the materials of the invention are able to solve one or more of the technical problems of the invention even though the plants from which they are obtained are no longer alive. Thus, according to a preferred variant of the invention, the material of plant origin comes from a dead plant, that is to say a plant which has been harvested, dried and possibly crushed. For the purposes of the present invention, a dead plant is a plant which is not capable of reproducing, of growing or of having physiological activity. Typically, the plants are harvested and left one or more days out of their culture medium before the preparation of a material of plant origin according to the present invention. This aspect is particularly advantageous in that it avoids the technical problem of growing plants for immediate or almost immediate preparation of materials of plant origin according to the present invention.

According to a preferred variant of the invention, the plant from which the material of plant origin used in the process of the invention is derived has not been cultivated on an effluent comprising at least one metal, typically a polluted effluent.

Advantageously, in the process of the invention, the material of plant origin rich in phenolic acids is preferably a powder of roots of water hyacinth or water lettuce, preferably of water hyacinth and preferably:

the powder is preferably obtained from the ends of the roots;

the roots are devoid of aerial parts and / or the material has undergone dehydration prior to its implementation.

Preferably in the process of the invention, the material of plant origin is selected from water hyacinth, water lettuce, pine bark, pine bark and pine cones.

For the purposes of the present invention, a material of plant origin comprising phenolic acids is a material of plant origin, insoluble in water, comprising an aromatic carbon skeleton and having at least carboxylic acid groups. These 5 carboxylic acid groups can be naturally present in the material of plant origin, or resulting from a chemical modification allowing the carbon skeleton to be enriched with carboxylic acid functions.

By "insoluble in water" is meant herein a material of plant origin which cannot be solubilized or dissolved in water. It necessarily forms a heterogeneous solid phase immiscible with water. For the purposes of the present invention, the term “insoluble” means that the limit of solubility in water of the material of plant origin is less than 1% by mass. Eventually, tiny parts are soluble (traces).

The presence of phenolic acids in the plant materials of the present invention can be determined by their infrared analysis (FT-IR). The principle is based on the comparison of the intensities of the vibrating bands of the aromatic ring and that of the C = O bond of the carboxylic acid unit.

The IR spectrum of the aromatic cycle is characterized by three vibration bands located between 1600 and 1400 cm- ¹ . The vibration band of the C = O bond of the COOH group is located between 1680 and 1620 cm ⁻¹ , depending on the degree of conjugation.

Thanks to this infrared analysis, we can determine the ratio of the intensity of the vibration band of the C = O bond of the COOH group and the intensity of each of the vibration bands of the aromatic ring.

Preferably, the infrared analysis is performed by the FT-IR spectrometer PerkinElmer Spectrum 100.

The infrared data for certain materials of plant origin are grouped together in Table 1 below. The DT value represents the difference of the transmittances T of two absorption bands, which allows the intensities of these bands to be quantified at the intensity of the incident signal. Transmittance is known to those skilled in the art.

Materials IR data of the C = O band of the COOH group (cm ' ¹ ) IR data of the aromatic ring (cm ^-1 ) Ratio of differences in transmittances (DT) between functional groups C = O / Ar Roots of 1620 1512 (DT = 3.0%) 2.9

water hyacinths (□ T = 8.6%) 1414 (QT = 5.1%) 1.7 Water lettuce roots 1626 (DT = 11.5%) 1513 (DT = 8.8%) 1416 (DT = 10.7%) 1.3 1.1 coffee grounds 1645 (DT = 8.2%) 1525 (DT = 5.6%) 14,434,414 (DT = 7.3%) 1.5 1.1 Tea grounds 1626 (DT = 7.2%) 1517 (DT = 5.5%) 1455 (DT = 6.4%) 1.3 1.1 Wheat straw 1654 (DT = 2.9%) 1598 (DT = 2.8%) 1510 (DT = 2.8%) 1426 (DT = 3.5%) 1 1 0.8 Cones 1658 (DT = 4.6%) 1602 (DT = 5.6%) 1510 (DT = 5.6%) 1441-1419 (QT = 6.2%) 0.8 0.8 0.7

Table l: Infra-red data of different materials of plant origin

Concerning the roots of water hyacinth and the roots of water lettuce, the intense and wide band at 1620 cm ' ¹ covers the aromatic band at 1600 cm' ¹ . In addition, the intensity of the band at 1620 is much higher than that of the bands at 1512 and! 414.

Regarding coffee and tea grounds, the intensity of the band at 1645 is much higher than that of the bands at 1525 cm- ¹ and 1443-1414 cm ¹ .

Regarding wheat straw, the intensity of the band at 1654 cm ' ¹ is lower than that of the band at 1426 cm' ¹ , and regarding pine cones, the intensity of the band at 1658 cm ' ¹ is 10 less than that of the bands at 1602, 1510 and 1441-1419 cm ' ¹ .

For each of these materials, it is possible to determine the ratio of the intensity of the vibration band of the C = O bond of the COOH group and the intensity of each of the vibration bands of the aromatic cycle, this ratio corresponding to the ratio of the absorbances of the respective 15 bands.

The term “material of plant origin rich in phenolic acids” means in particular a material of plant origin characterized by a ratio of the intensity of the vibration band of the C = O bond of the COOH group and of the intensity each of the vibration bands of the aromatic cycle greater than 1, preferably between 1 and 4, even more preferably between 1 and 3.5.

Alternatively, the ratio of the intensity of the vibration band of the C-0 bond of the COOH group and the intensity of each of the vibration bands of the aromatic ring greater than 1.5.

We prefer to choose the maximum value of the ratio of the intensity of the vibration band of the C = O bond of the COOH group and the intensity of each of the vibration bands of the aromatic ring so that the material is insoluble. For certain materials, a certain solubility can appear by exceeding a value of this ratio of the bands characterizing the phenolic acids. This maximum value, for the ratio of the bands, may for example be 3.5 or 3.

According to this definition, water hyacinth roots, water lettuce roots, coffee grounds and tea grounds are considered to be materials rich in phenolic acids. On the contrary, wheat straw and pine cone are not considered to be materials rich in phenolic acids and will only be advantageous after functionalization.

Furthermore, the term “material rich in phenolic acids” also means, within the meaning of the present invention, a material of plant origin comprising phenolic acid functions and being capable of binding more than 90%, preferably more than 95%, preferably. more than 99%, advantageously 100% by weight of at least one metal included in an effluent, for example said effluent comprising from 0.1 to 1000 mg / L of at least one metal. By "fix" is meant within the meaning of the present invention a complexation reaction between the phenolic acids included in the material of plant origin and the metals with which it is in contact. Advantageously, the material of plant origin rich in phenolic acids is capable of fixing more than 90%, preferably more than 95%, preferably more than 99% by weight of at least one metal in ionic form included in an effluent, for example example said effluent comprising from 0.1 to 1000 mg / L of at least one metal.

By the expression "a metal in ionic form" is meant a metal in the form M (I), M (III), M (IV), M (V) or M (VI). Preferably, the metal is in cationic form.

It is also understood that the adsorption or metal binding capacity in ionic forms of the material of plant origin and therefore the percentage of decontamination generally depends both on the mass of said material brought into contact with the medium containing the metals. in ionic forms and the quantity by mass of metals in ionic forms contained in the medium to be decontaminated. For the purposes of the present invention, the term “absorption capacity” means the ability of the material of plant origin to bind metals to its surface. By surface is meant the internal and external surface of the material. The absorption capacity can be expressed in mmol of metal per gram of sorbent, or in grams of metal per gram of sorbent.

The inventors of the present application have discovered that the fact that the materials of plant origin can fix the metals included in an effluent was very probably due to the presence of natural or functionalized phenolic acids in these materials. We are talking about biosorption. We also speak of a biosorbent for the material of plant origin according to the invention.

For the purposes of the present invention, the term “biosorption” means the non-physiological physicochemical process, by which the plant materials rich in phenolic acids of the present invention adsorb certain metals. Biosorption takes place during contacting step b) of the process of the invention.

By "preparation of a material of plant origin" is meant any step necessary to obtain a material of plant origin, such as a dehydration step and / or a grinding step.

Typically, a PI process according to the present invention comprises in step a), preparation of the material of plant origin, a step of dehydration and optionally of grinding the plant from which the material is obtained.

By dehydration is meant a treatment of the material of plant origin preferably at a temperature between 20 ° C and 90 ° C, preferably in air.

The grinding step can be carried out using a grinder mixer for a few minutes. This step makes it possible to obtain a material of crushed plant origin, preferably in the form of a powder, preferably in the form of a powder, the particle size of which is less than 1.5 mm, and for example between 0.5 and 1. , 5 mm. The particle size is preferably measured on a sieve with 1.5 mm mesh openings. Thus, the particle size represents the maximum dimension of the powder grains of the material of plant origin. Grinding can be applied to all materials of plant origin. Advantageously, the coffee and tea grounds do not undergo a grinding step. However, they are washed thoroughly with hot water until the soluble products they contain are removed.

Following the grinding step, the powder obtained can be washed with water, preferably between 25 and 50 ° C, then this powder is filtered, preferably on cellulose, and dried at a temperature between 40 and 90 ° C, for example in an oven at 80 ° C for 12 hours.

Materials rich in tannin are washed, filtered and dried under the same conditions as those described above.

Materials rich in lignin are first washed, preferably with isopropanol, in order to remove resin acids. They are then ground using a grinder mixer for a few minutes. The powder obtained is washed again, preferably with isopropanol, then with hot water, filtered through cellulose, before being dried in an oven at 80 ° C for 12 hours.

Preferably, the material of plant origin used in step a) of the invention is devoid or substantially devoid of metals chosen from the group of platinoids and in particular Pt, Pd or Rh, rare earths and in particular Ce, Eu , Yb and Sc; or from the group comprising Zn, Mn, Ni, Cu, Fe, Al, Ca, Mg, As, Sb, Cr, Cd, Ni and Co, preferably from the group comprising Zn, Mn, Ni, Cu, Fe, Al , Ca, Mg, As, Cd, Ni and Co. Advantageously, each content of Fe, Al, Cu, Ni, Zn and Mn in the material of plant origin used in step a) of the invention is less than 0, 01% by weight.

Typically, the material of plant origin used in step a) of the invention comprises at least one physiological metal chosen from Ca, K, Mg or Na. Preferably, the material of plant origin used in step a) of the invention comprises from 0.1 to 3.5% by weight of at least one metal chosen from Ca, K, Mg or Na.

Advantageously, the material can comprise from 0.8 to 3.4% by weight of Ca, from 0.1 to 0.8% by weight of K, from 0 to 0.5% by weight of Mg and 0 to 0, 7% by weight of Na. Preferably, the water hyacinth roots comprise 3.4 wt% Ca, 0.8 wt% K, 0.5 wt% Mg and 0.7 wt% Na; the coffee grounds include 0.5 wt% Ca, 0.8 wt% K, 0.2 wt% Mg; the pine cone comprises 0.5 wt% CA and 0.2 wt% K; and the pine bark comprises 0.8 wt% Ca and 0.1 wt% K.

During the step of bringing into contact b) the material of plant origin obtained at the end of step a) with an effluent comprising from 0.1 to 1000 mg / L, preferably from 5 to 100 mg / L, preferably 14 to 40 mg / L of at least one metal; the material of plant origin, which is then preferably in the form of a powder insoluble in water, is added to an effluent comprising from 0.1 to 1000 mg / L, preferably from 5 to 100 mg / L, preferably 14 to 40 mg / L of at least one metal. The material is added in an amount sufficient to fix said at least one metal in ionic form. This amount is determined by studying the absorption capacity of each material of plant origin. Step b) of contacting can be carried out by any means known to those skilled in the art, for example by eluting the effluent in a column comprising the material of plant origin. The material of plant origin can initially include physiological metals (Ca, Na, K) and releases them when it comes into contact with the effluent (step b). The system is similar to an ion exchange resin: Na and K are replaced by Fe and Mn.

For the purposes of the present invention, the term “effluent” is understood to mean an aqueous liquid medium, which may for example be chosen from:

a reaction medium in which a chemical reaction involving a metal catalyst has been carried out; or an effluent from a reaction medium in which a chemical reaction involving a metal catalyst has been carried out; or an effluent of extractive or industrial origin, for example from mines, quarries or the steel industry and comprising metallic elements.

The metals present in the effluents can be divided into three categories:

Strategic resources: platinoids (Pd, Pt, Rh, ...) and rare earths (Ce, Eu, Yb, Sc, ...);

Primary resources: Zn, Mn, Ni, Cu, Fe, Al, Ca, Mg;

Toxic elements: As, Sb, Cr, Cd, Pb, Ni, Co.

Preferably, the effluent comprises at least one metal chosen from the group of platinoids and in particular Pt, Pd or Rh, rare earths and in particular Ce, Eu, Yb and Sc; or from the group comprising Zn, Mn, Ni, Cu, Fe, Al, Ca, Mg, As, Sb, Cr, Cd, Ni and Co, preferably from the group comprising Zn, Mn, Ni, Cu, Fe, Al , Ca, Mg, As, Cd, Ni and Co. Advantageously, the effluent comprises a metal chosen from the group comprising Cu, Pb, Cd or Ni or from the group comprising Pd, Sc, Co, Fe, Mn, As, Ce, Eu, Yb.

Advantageously, the effluent comprises at least one metal in ionic form chosen from scandium (Sc), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) , lead (Pb), zinc (Zn), ruthenium (Ru), palladium (Pd), cadmium (Cd), iridium (Ir), rhodium (Rh), platinum (Pt), lithium (Li), osmium (Os), mercury (Hg), arsenic (As), antimony (Sb), chromium (Cr), aluminum (Al) or a metal of lanthanide series including europium (Eu), ytterbium (Yb), cerium (Ce).

Advantageously according to the invention, the effluent is an effluent of extractive or industrial origin comprising metallic elements and in particular an effluent originating from a quarry and comprising at least one metal chosen from iron (Fe), manganese (Mn), zinc (Zn), nickel (Ni), copper (Cu), lead (Pb), scandium (Sc), cerium (Ce) and lithium (Li), or osmium (Bone).

According to one variant, the effluent comprises one or more metals chosen from among Pb, Sc, Eu, and Ce, or from rare earths, or from Co and Fe, Mn, or from Cr, Zn Ni, As, Cd or Cu.

Advantageously, step b) of the process of the invention takes place for a time sufficient to fix a satisfactory quantity of metal by the material of plant origin, and typically takes place for at least one hour, preferably at least. two hours, or for a period of between 1 and 2 hours. Preferably, the temperature of this step is greater than 0 ° C, preferably between 10 ° C and 30 ° C, preferably between 20 ° C and 25 ° C.

Following this step b), the medium comprising the effluent and the material of plant origin can be filtered in order to recover the material of plant origin comprising at least one metal. Advantageously, the material of plant origin has fixed at least 90%, preferably more than 95%, preferably more than 99% by weight, advantageously substantially 100% of said metal present in the effluent. This filtration can be done in “batch” mode or on a column. By "substantially" is meant here that the metal remaining in the effluent is in trace form.

Advantageously according to the process of the invention, when the plant material is water hyacinth, the effluent comprises at least one metal chosen from Sc, Ni, Ce, Yb, Co, Ni, Cu, Pd, Pt, Rh, Mn, Fe, Zn, As, Cr or Sb, preferably from Sc, Ni, Ce, Yb, Co, Ni, Cu, Pd, Pt, Mn, Fe, Zn or As; when the plant material is water lettuce, the effluent comprises at least one metal selected from Pd, Pt, Rh or Ni, preferably from Pd, Pt or Ni;

when the plant material is coffee grounds, the effluent comprises at least one metal chosen from Pd, Pt, Rh, Mn, Fe, Zn, Ni or Cd, preferably from Pd, Pt, Mn, Fe, Zn, Ni or Cd.

Advantageously, at the end of step b), the material of plant origin is dried in an oven, preferably at a temperature between 70 ° C and 90 ° C, preferably at 85 ° C, then it is treated. thermally, for example at 550 ° C for 6 hours.

Preferably, the material of plant origin obtained during step c) comprises at least one metal chosen from the group of platinoids and in particular Pt, Pd or Rh, rare earths and in particular Ce, Eu, Yb and Sc ; or from the group comprising Zn, Mn, Ni, Cu, Fe, Al, Ca, Mg, As, Sb, Cr, Cd, Ni and Co; advantageously chosen from the group comprising Cu, Pb, Cd or Ni or from the group comprising Pd, Sc, Co, Fe, Mn, As, Ce, Eu, Yb.

Advantageously, the material obtained according to the process of the invention comprises from 1 to 20% by weight, for example from 1 to 10% by weight of metals chosen from Sc, Ni, Ce, Yb, Co, Ni, Cu, Pd, Pt, Mn, Fe, Zn, As or Cd.

Preferably, the metal content in the material of plant origin obtained during step c) is determined by MP-AES (microwave plasma atomic emission spectrometry) or ICP-MS (plasma mass spectroscopy). inductively coupled). This metal content can be measured directly after the drying and heat treatment carried out before step c). The metal content is expressed as a function of the total weight of material of plant origin obtained at the end of step b).

The invention also relates to a P2 method for depolluting or treating an effluent comprising at least one metal, said method comprising the following steps:

at. a preparation of a material of plant origin from a dead plant chosen from:

aquatic plants, preferably the roots of aquatic plants such as water hyacinth or water lettuce;

materials rich in tannins such as coffee grounds or tea grounds;

lignin-rich materials such as wheat straw, pine bark, pine cones, coconut husks;

and obtaining a material of plant origin, rich in phenolic acids, in which the ratio of the intensity of the vibration band of the C = O bond of the COOH group and of each of the vibration bands of the aromatic ring determined in FT-IR is between 0.5 and 4, preferably between 1 and 3.5, for example between 1 and 2.5;

b. bringing the material of plant origin obtained at the end of step a) into contact with an effluent comprising from 0.1 to 1000 mg / L of at least one metal, preferably for a period of between 1 hour and 2 hours, at a temperature preferably between 10 and 30 ° C, and

vs. obtaining an effluent comprising less than 100 mg / L by weight of said at least one metal.

The depollution process of the invention advantageously makes it possible to achieve environmental rejection standards and can be chemoselective.

All of the embodiments, variants, and preferred characteristics of the PI process apply, alone or in any of their combinations, also to the P2 depollution process of the invention.

Advantageously, the sufficient quantity of material of plant origin is from 0.5 g to 20 g / L to decontaminate industrial effluents containing concentrations of metal in ionic form of 5 to 500 mg / L. This is especially true when the metal is chosen from scandium (Sc), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), lead (Pb ), zinc (Zn), ruthenium (Ru), palladium (Pd), cadmium (Cd), iridium (Ir), rhodium (Rh), platinum (Pt), lithium (Li) , osmium (Os), mercury (Hg), arsenic (As), antimony (Sb), chromium (Cr), aluminum (Al) or a metal from the lanthanide series, in particular l 'europium (Eu), ytterbium (Yb), cerium (Ce).

Preferably, step c) of method P2 makes it possible to obtain an effluent comprising from 0 to 100 mg / L, preferably from 0 to 50 mg / L, advantageously from 0 to 15 mg / L, even more advantageously from 0 at 5 mg / L of at least one metal chosen from Sc, Ni, Ce, Yb, Co, Ni, Cu, Pd, Pt, Mn, Fe, Zn, As or Cd.

According to a particular embodiment, the material of plant origin which was prepared at the end of step a) in the PI or P2 processes of the invention is characterized by a ratio of the intensity of the band of vibration of the C = O bond of the COOH group and of the intensity of each of the vibration bands of the aromatic cycle determined in FT-IR less than 1, preferably between 0 and 1.

In this case, the PI or P2 processes can comprise a step of functionalizing the material of plant origin obtained at the end of step a), said step being prior to step b), and obtaining a material of plant origin in which the ratio of the intensity of the vibration band of the C = O bond of the COOH group and of the intensity of each of the vibration bands of the aromatic cycle determined in FT-IR is greater than 1, preferably between 1 and 3, even more preferably between 1 and 2.5. Pine cones and pine bark are characterized by a ratio of the intensity of the vibration band of the C = O bond of the COOH group and the intensity of each of the vibration bands of the aromatic cycle determined in FT-IR less than 1, but the functionalization step is not necessary for ccs materials which complex palladium.

When the PI or P2 processes according to the invention include a functionalization step, this can be carried out for example via:

a carboxylation reaction of the material of plant origin obtained at the end of step a) with a carboxylic acid anhydride in an aprotic polar solvent such as ethyl acetate, the anhydride being preferably chosen from mixed, cyclic, aliphatic, functionalized anhydrides generated in situ or prior to the implementation of the carboxylation reaction; or an autocatalyzed esterification reaction between the material of plant origin obtained at the end of step a) and a polyacid, this reaction taking place in a solvent preferably chosen from ethanol or ethyl acetate ; or an esterification reaction followed by hydrolysis and transfunctionalization.

Advantageously, the functionalization step can be carried out via the opening of functionalized or non-functionalized anhydrides, generated in situ or prepared beforehand, such as glutaric anhydride, preferably cyclic carboxylic anhydrides with five centers, preferably succinic anhydride. , aconitic and itaconic anhydrides, with a polyacid by autocatalysis, preferably citric acid, succinic acid, maleic acid or glutaric acid introduced in a non-aqueous medium, preferably aprotic, such as acetate d 'ethyl.

The present invention also relates to a material of plant origin, rich in phenolic acids, optionally comprising at least one metal, said material being capable of being obtained according to the P1 or P2 process of the invention, and optionally comprising phenolic acid functions. functionalized.

The present invention also relates to a material of plant origin, rich in phenolic acids, optionally comprising at least one metal, characterized in that said plant origin is chosen from:

- aquatic plants, preferably the roots of aquatic plants such as water hyacinth or water lettuce;

- materials rich in tannins such as coffee grounds or tea grounds;

- materials rich in lignin such as wheat straw, pine cones, pine bark, coconut husks, said material exhibiting a ratio of the intensity of the vibration band of the C = O bond of the group COOH and the intensity of each of the vibration bands of the aromatic cycle determined in FT-IR is greater than 1, preferably between 1 and 3, and optionally comprising functionalized phenolic acid functions.

Advantageously, the material of plant origin according to the invention is characterized by a degree of functionalization of between 0.0007 and 0.0014 molNaon / g of material in the case of water hyacinth and between 0.0006 and 0, 0018 moRaon / g of material in the case of coffee grounds. This degree of functionalization can be measured by titration of the functionalized material using a solution of NaOH (2M) until a pH equal to 7 is obtained.

The inventors of the present application have surprisingly shown that the use of materials of plant origin crushed and packaged in powder form, for example, a powder of the roots of aquatic plants, in particular water hyacinth, makes it possible to fix metals chosen in particular from scandium (Sc), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), lead (Pb), zinc ( Zn), ruthenium (Ru), palladium (Pd), cadmium (Cd), iridium (Ir), rhodium (Rh), platinum (Pt), lithium (Li), osmium ( Os), mercury (Hg), arsenic (As), antimony (Sb), chromium (Cr), aluminum (Al) or a metal from the lanthanide series, in particular europium (Eu ), ytterbium (Yb), cerium (Ce) more efficiently in comparison with the use of living plants fixing metals by rhizofiltration.

Materials of plant origin comprising at least one metal and obtained by the methods of the invention, and therefore having fixed at least one metal in ionic form chosen in particular from scandium (Sc), manganese (Mn), iron ( Fe), cobalt (Co), nickel (Ni), copper (Cu), lead (Pb), zinc (Zn), ruthenium (Ru), palladium (Pd), cadmium (Cd) , iridium (Ir), rhodium (Rh), platinum (Pt), lithium (Li), osmium (Os), mercury (Hg), arsenic (As), antimony ( Sb), chromium (Cr), aluminum (Al) or a metal from the lanthanide series, in particular europium (Eu), ytterbium (Yb), cerium (Ce), can be directly upgraded by ecocatalysis.

The invention also relates to a process P3 for preparing an organic synthesis reaction catalyst comprising a heat treatment of a material of plant origin comprising at least one metal according to the invention or obtainable according to one. any of the processes of the invention, preferably at a temperature between 500 and 800 ° C and preferably for a period of between 2 and 8 hours, and obtaining a calcined material

The present invention also relates to a material of plant origin comprising at least one metal or capable of being obtained according to the methods of the invention. Advantageously, the material of plant origin comprising at least one metal or capable of being obtained according to the methods of the invention comprises the mixed salt: CazMnsOs.

All of the embodiments, variants, and preferred characteristics of the PI and P2 processes apply, alone or in any of their combinations, also to the P3 process.

For the purposes of the present invention, the heat treatment is carried out in air or under an argon atmosphere in an oven, preferably for a period of between 4 and 6 hours.

The heat treatment can also be carried out in two stages, the first at a temperature below 500 ° C preferably of the order of 350 ° C and in a second stage at a temperature of the order of 550 ° C each of these. steps being carried out for about 3 hours. Preferably, the heat treatment is carried out at 550 ° C. for 6 hours.

Preferably, the P3 process comprises an acid treatment of the calcined material.

Preferably, the acid treatment is carried out with hydrochloric acid, in particular hydrochloric acid at a concentration between 0.1N and 12N, formic acid, sulfuric acid, hydrobromic acid. , tnfluoroacetic acid or trifluoromethanesulfonic acid.

The calcined materials can be activated and used in chemical catalysis for the synthesis of high added value biomolecules. The opportunities derived from the new type of biomass proposed are numerous and reveal a considerable number of possibilities in acid catalysis, green oxidations, redox reactions, and couplings, and in particular in the homogeneous phase.

Thus, the invention relates to a P4 process for carrying out an organic synthesis reaction involving the calcined material as a catalyst.

Advantageously, the method P4 comprises the following steps.

- the heat treatment of a material of plant origin comprising at least one metal according to the invention or obtainable according to any one of the processes of the invention, preferably at a temperature between 500 and 800 ° C and preferably for a period of between 2 and 8 hours, and obtaining a calcined material;

- the implementation of an organic synthesis reaction involving the calcined material as a catalyst.

All of the embodiments, variants, and preferred characteristics of the PI, P2 and P3 processes apply, alone or in any of their combinations, also to the P4 process.

Advantageously, in process P4, the implementation of an organic synthesis reaction of the invention is carried out without adding metal from another origin than the calcined material.

According to the present invention, the term “catalyst” is understood to mean the product obtained following the process.

P3.

The present application also relates to the use as a catalyst and in particular in a homogeneous phase, of a composition containing a metal catalyst originating, optionally after acid treatment, from the ash obtained by heat treatment of a material of plant origin, in the form of 'a powder insoluble in water in an amount sufficient to fix at least 90%, 95% or preferably 100% of the metal (s) present in the liquid medium to be treated, rich in phenolic acids, having fixed at least one metal in the form ionic chosen in particular from scandium (Sc), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), lead (Pb), zinc (Zn) ), ruthenium (Ru), palladium (Pd), cadmium (Cd), iridium (Ir), rhodium (Rh), platinum (Pt), lithium (Li), osmium (Os ), mercury (Hg), arsenic (As), antimony (Sb), chromium (Cr), aluminum (Al) or a metal from the lanthanide series in particular europium (Eu), ytterbium (Yb), cerium (Ce), a metal catalyst, the metal or metals of which are chosen from the metals originating from said material and of which the metal or metals present in the composition of the invention come exclusively from the material of plant origin and without the addition of metal originating from another origin than the said material for the implementation of organic synthesis reactions involving the said catalyst.

Preferably, the reactions used in the process of the invention are chosen from coupling reactions, preferably chosen from;

the coupling reactions between heterocyclic or non-heterocyclic brominated derivatives with boronic acids such as the Suzuki reaction;

o the Heck reaction;

o Sonogashira's reaction;

o polymer construction reactions such as polycondensations, reduction reactions, in particular chosen from:

o the reduction reaction of an enone;

o the reduction reaction of a carbonyl derivative;

- the isomerization reaction of an exocyclic double bond;

oxidation reactions, preferably selected from the oxidation of alcohols;

oxidative halogenation reactions;

electrophilic substitution reactions, such as nitration or thiocyanation reactions;

condensation reactions, preferably condensation reactions of a carbanion with a carbonyl compound (Doebner-Knoevenagel type reaction);

multi-component reactions such as the Biginelli reaction; and alkene oxidation reactions such as epoxidation and oxidative cleavage.

A subject of the invention is also the use as described above or the process as described above comprising the preparation, as catalyst, of a composition containing a metal catalyst originating, optionally after acid treatment, from the ashes obtained by heat treatment of a material of plant origin in the form of a powder insoluble in water in an amount sufficient to fix at least 90%, 95% or preferably 100% of the metal or metals present in the liquid medium to be treated rich in phenolic acids, having fixed at least one metal in ionic form chosen in particular from scandium (Sc), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper ( Cu), lead (Pb), zinc (Zn), ruthenium (Ru), palladium (Pd), cadmium (Cd), iridium (Ir), rhodium (Rh), platinum (Pt ), lithium (Li), osmium (Os), mercury (Hg), arsenic (As), antimony (Sb), chromium (Cr), aluminum (Al) or a metal from the l series anthanides in particular europium (Eu), ytterbium (Yb), cerium (Ce), characterized in that the organic synthesis reactions involving said catalyst are chosen from:

oxidation reactions reduction reactions cross-coupling and homocoupling reactions such as carbon-carbon bond formation reactions such as Suzuki reaction, Heck reaction, Sonogashira reaction, polymerizations, polycondensations reactions involving a Lewis acid catalysis preferably chosen from electrophilic aromatic substitution reactions (ARES), pericyclic reactions, multicomponent reactions, cascade reactions, addition reactions, transfunctionalization reactions, esterifications , carboxylations, halogenations, nitrations, thiocyanations, aldol or crotonization reactions or related reactions, preferably Knoevenagel reactions, Perkin reactions, Claisen reactions, Tollens reactions or Thorpe reactions - Ziegler.

multi-step reactions comprising an oxidation or reduction reaction followed by Lewis acid catalysis isomerization reactions

Advantageously, the organic synthesis reactions can be functional transformation reactions by catalysis chosen from oxidation reactions such as the Wacker-Tsuji oxidation, the oxidation of alcohols, the oxidative coupling of aromatic compounds, reduction such as reduction of olefins and nitro and nitrile compounds or hydrosilylation of olefins and alkynes, catalytic hydrogenation, cross coupling and homocoupling such as carbon-carbon bonding reactions such as the carbon-carbon bonding reaction Suzuki, Heck's reaction, Sonogashira's reaction, reactions of nucleophilic addition of an enamine to pi-allylic complexes, reactions of the Buchwald-Hartwig type, carbonylation reactions and ene-reactions, regioselective reactions between an alkene and an alkene. aromatic derivative, cyclopropanation of alkenes, cycloadditions, cascade carbocylization of polyunsaturated compounds, allylic isomerization, cy cloaddition, ene reactions, cycloisomerizations, hydroboration, polymerization reactions, polycondensations, syntheses of unsaturated and conjugated polymers.

Even more preferably, the organic synthesis reactions are chosen from the following reactions: oxidation reactions, reduction reactions, cross-coupling and homocoupling reactions, reactions involving Lewis acid catalysis preferably chosen from electrophilic aromatic substitution reactions (ARES), pericyclic reactions, multicomponent reactions, cascade reactions, addition reactions, halogenations, aldol or crotonization reactions or related reactions such as condensation reactions of an aldehyde on a deactivated compound of the Knoevenagel type, the Perkin reaction, the Tollens reaction, the Thorpe reaction, the Claisen reaction, or the Mukaiyama reaction; combination reactions oxidation or reduction by Lewis acid catalysis, brominations, protections such as chemoselective tritylations of alcohols and amines, acylations, in particular acetylations of alcohols, phenols, thiols and amines, silylations of alcohols, oximes, enolates, phenols, amines and anilines, the formation of imines or amines, the deprotection of functions in particular detritylation, concerted rearrangements such as ene-reactions or cycloadditions, pinacolic or Beckmann transposition, the Claisen-Schmidt reaction, the Mukaiyama reaction or reactions of the Knoevenagel type, dehydration or transfunctionalization reactions such as transamination or transtritylation reactions, reactions for the preparation of polyheterocyclic structures such as porphyrinogens or dithienylpyrroles, multicomponent reactions such as triazole synthesis reactions, Hantzsch reactions, syntheses of optionally substituted piperidines, biomimetic reactions and hydride transfers, even more preferably among oxidation reactions, reduction reactions, cross-coupling and homocoupling reactions, reactions of electrophilic aromatic substitution (ARS), pericyclic reactions, multicomponent reactions, cascade reactions, addition reactions, halogenations, aldol or crotonization reactions or related reactions such as condensation reactions of an aldehyde on a deactivated compound of the Knoevenagel type, the Perkin reaction, the Tollens reaction, the Thorpe reaction, the Claisen reaction, or the Mukaiyama reaction; combination reactions oxidation or reduction, electrophilic aromatic substitution reactions, construction of heterocycles, preparation and protection of carbonyl derivatives, radical oxidation, epoxidation, oxidation of alcohols located in alpha of an aromatic group heterocyclic or carbocyclic or of a double bond, the oxidative cleavage of polyols, the oxidation of benzamines, the oxidative aromatic dehydrogenation of unsaturated and / or conjugated cyclic derivatives optionally comprising a heteroatom, the direct halogenation of enolizable compounds, the Hantzsch reaction in catalysis Lewis acid between an aldehyde, a beta-dicarbonyl compound and a source of ammonium leading to the formation of dihydropyridines (DHP), advantageously from reduction reactions, cross-coupling and homocoupling reactions, reactions involving a Lewis acid catalysis preferably chosen from substitution reactions aromatic electrophile (SEAr), pericyclic reactions, multicomponent reactions, cascade reactions, addition reactions, halogenations, aldol or crotonization reactions or related reactions such as condensation reactions of an aldehyde on a compound deactivated of the Knoevenagel type, the Perkin reaction, the Tollens reaction, the Thorpe reaction, the Claisen reaction, or the Mukaiyama reaction; halogenation reactions in particular halogenation of primary, secondary and tertiary alcohols (Lucas reaction), electrophilic aromatic reactions in series, substitutions or additions, Friedel-Crafts alkylations, preferably the reaction between toluene and chloride of benzyl to obtain 4- and 2-methyldiphenylmethane, Friedel-Crafts acylations preferably the synthesis of methylacetophenone, multicomponent reactions, in particular the Biginelli reaction leading to the synthesis of dihydropyrimidinones or dihydrothiopyrimidinones, preferably 3 , 4-dihydropyrimidin2 (lH) -one or 3,4-dihydropyrimidin-2 (lH) -thione, and the Hantzsch reaction preferably used to prepare dihydropyridines, the synthesis of 5-ethoxycarbonyl-6-methyl-4isobutyl -3,4-dihydropyrimidin-2 (1H) -one, the reaction between 3-hydroxybenzaldehyde, ethyl 3-ketopentanoate and thiourea to obtain 6-methyl 1-4- (3-hydroxyphenyl) -2-thioxo1, 2,3,4 ethyl tetrahydro pyrimidin-5-carboxylate (monastrol), cycloaddition reactions, in particular the Diels-Alder reaction such as the reaction of cyclopentadiene with diethyl fumarate or the reaction of 3-buten-2-one with 2,3-dimethyl-1,3-butadiene, transesterification reactions, preferably reaction of methyl palmitate and butan-1-ol, synthesis of amino acid complexes or oximes, preferably Cu d oximes complexes, catalyzed hydrolysis of organosulfur functions, in particular thiophosphates such as parathion, catalyst synthesis reactions for hydrogenation reactions after reduction of Ni (II) to Ni (0), reduction reactions such as reduction of 1-phenyl 2nitroprene to 1-phenyl 2-aminopropane, coupling reactions including cross-coupling reactions, in particular Suzuki reaction to preferably synthesize diaryl compounds such as 3-methoxy-4 ' -methylbiphenyl, reac tion of Heck, and the reaction of Ullmann (in particular the nucleophilic aromatic substitutions such as N and O-arylations), the condensation of diamines on carbonyl derivatives, in particular the synthesis of 1H-1,5benzodiazepines preferably from l 'o-phenylenediamine and acetone, the chemoselective hydrolysis of methyl esters in peptide chemistry, in particular the deprotection of carbonyl groups without cleavage of Fmoc, of Fmoc-Gly-OMe and Fmoc-Gly-Phe-Pro-OMe , chemoselective hydrolysis of 6,7-dideoxy-1,2: 3,4-di-O-isopropyldine-7 - [(9fluorenylmethoxycarbonyl) amino] -D-glycero-aD-galacto-octopyranuromethyl ester to '' obtain an amino acid derived from galactose, the synthesis of oligonucleotides protected in 5 ', the synthesis of 5'-GpppT6 and 5'-GpppRNAs, the coupling of phosphoro-imidazolidate T6 on a solid support with GDP in particular the synthesis of 5 '-guanosyl triphosphate hexa-2'-deoxythymidylate (GpppT6), reductive amination, preferably the form catalyzed ation of imines followed by their reduction in situ, synthesis of secondary amines and substituted anilines, chlorination of alkenes such as chlorination of dicyclopentadiene, aromatic halogenation reactions without dihalogen, nitration reactions without nitric and sulfuric acid, thiocyanation reactions, synthesis of bromo- and iodoanisole, successive or cascade reactions such as addition, dehydration, cycloaddition, or electrocyclization reactions, synthesis of tenzopyranes and cannabinoids or dihydrocannabinoids and in particular the condensation of diamines on carbonyl derivatives, reducing aminations, reactions of aromatic halogenations without dihalogen, the Ullmann reaction, successive or cascade reactions such as reactions of addition, dehydration, cycloaddition or cyclization, reactions of cross coupling or not such as the Suzuki reaction, electrophilic aromatic reactions in s Erie, substitutions or additions, multicomponent reactions, in particular the Biginelli reaction.

A subject of the invention is also a process for recycling metal catalysts, in particular metal catalysts comprising at least one metal in ionic form chosen in particular from scandium (Sc), manganese (Mn), iron (Fe), iron. cobalt (Co), nickel (Ni), copper (Cu), lead (Pb), zinc (Zn), ruthenium (Ru), palladium (Pd), cadmium (Cd), iridium (Ir), rhodium (Rh), platinum (Pt), lithium (Li), osmium (Os), mercury (Hg), arsenic (As), antimony (Sb), chromium (Cr), aluminum (Al) or a metal from the lanthanide series, in particular europium (Eu), ytterbium (Yb), cerium (Ce), said process being characterized by the following steps:

-a treatment of a reaction medium in which a chemical reaction using said soluble metal catalyst has been carried out, with a material of plant origin rich in phenolic acids in the form of a powder insoluble in water in an amount sufficient to fix at least 90%, 95% or preferably 100% of the metal (s) in ionic form present in the reaction medium to be treated, and

- filtration to recover said material of plant origin rich in phenolic acids having fixed the metal or metals in ionic form present in the reaction medium,

a heat treatment of said material of plant origin rich in phenolic acids, having fixed the metal or metals in ionic form to obtain ash constituting the recycled metal catalyst comprising at least one metal in ionic form chosen in particular from scandium (Sc) , manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), lead (Pb), zinc (Zn), ruthenium (Ru), palladium (Pd), cadmium (Cd), iridium (Ir), rhodium (Rh), platinum (Pt), lithium (Li), osmium (Os), mercury (Hg), l 'arsenic (As), antimony (Sb), chromium (Cr), aluminum (Al) or a metal from the lanthanide series, in particular europium (Eu), ytterbium (Yb), cerium (This).

The recovery of materials of plant origin having fixed at least one metal offers at least one advantage over previous applications of plant materials having fixed metal cations to obtain biocatalysts:

the materials of plant origin having fixed at least one metal of the present invention make it possible to carry out organic synthesis reactions in the presence of said materials in a recyclable homogeneous phase, while generally, homogeneous catalysis does not make it possible to separate the catalyst of the reaction medium, because the catalyst is in the same phase as the reactants and products of the catalyzed reaction. Thanks to the materials of the invention, the metal catalyst is easily recoverable by bringing a material of plant origin into contact in the form of a powder of plant waste, for example coming from the roots of certain aquatic plants (examples: roots of water hyacinth or water lettuce), vegetable waste rich in tannins (examples: coffee and tea grounds) or vegetable waste rich in lignin (wheat straw, pine cones, coconut husks) with the reaction medium after catalysis to recover the metal / plant material complex rich in phenolic acids isolated by simple filtration and rinsing, thus the homogeneous phase bio-sourced catalysts of the present invention are recyclable.

Furthermore, the performance of materials of plant origin having fixed at least one metal of the invention is often superior to that of their commercial counterparts of non-plant origin. In fact, the materials of the present invention have better catalytic activity. For example, the material according to the invention comprising at least palladium is active from 0.001 mole%, preferably 0.0025 to 0.01 mole% of palladium in M (II) form.

The present invention makes it possible to valorize materials of plant origin while providing a catalyst material for a chemical reaction.

The present invention makes it possible to recover materials of plant origin while recycling metals.

The present invention makes it possible to enhance materials of plant origin while decontaminating effluents containing one or more metals.

The invention will now be described using the following non-limiting examples.

Example 1: Recycling of palladium (Pd)

Example 1.1: Study of the variation in Pd in different quantities of air-dried, ground and sieved root extracts on a sieve with a mesh size of 1.5 mm of water hyacinths placed in a solution comprising 14 mg / L in Pd at pH = 2.5-3. The concentration of root extract (ER) was varied from 1 g / L to 2 g / L, and the duration of the contact from 30 min to 2 hours. The root extracts are heat treated at 550 ° C. before analysis. The results are shown in Table 2.

Label variable Pd Initial concentration in the effluent mg / L 14.25 Metal content in the root extract after biosorption (E.R.) 1 g / L, 0.5 h % mass 20.38 E.R.l g / L, 2 h % mass 23.76 E.R. 1.5 g / L, 0.5 h % mass 15.19 E.R. 1.5 g / L, 2 h % mass 17.74 E.R. 2 g / L, 0.5 h % mass 11.99 E.R. 2 g / L, 2 h % mass 13.88

Table 2: Recycling of palladium

Example 1.2: Study of the quantity of Pd remaining in the effluent after bringing into contact with different quantities of root extracts of water hyacinths placed in a solution of 14 mg / L in Pd, at a pH of 2.5- 3 and with a biomass / effluent volume ratio of 0.2g / 0.2L.

Label variable Pd Treated solution 1 g / L, 0.5 h mg / L 2.09 Treated solution 1 g / L, 2 h mg / L 1.59 Treated solution 1.5 g / L, 0.5 h mg / L 1.51 Treated solution 1.5 g / L, 2 h mg / L 0.01 Treated solution 2 g / L, 0.5 h mg / L 0.04 Treated solution 2 g / L, 2 h mg / L 0 Table 3: Pd concentration in an effluent brought into contact with a root extract of

water hyacinth.

Materials from the roots of water hyacinth make it possible to achieve total decontamination of effluents.

Example 1.3 (comparative): Rhizofiltration using live roots of water hyacinth (1.5 g) on a solution of 200 ml at 14 mg / L of Pd and study of the variation in elements over time in the root extracts and in solution

Label variable Pd Initial solution at t = 0 mg / L 14.18 Solution treated at t = 0.5 h mg / L 8.49 Solution treated at t = 2 h mg / L 4.74 Roots at t = 0.5 h % mass 7.64 Roots at t = 2 h % mass 21.44

Table 4: Rhizofiltration

Example 1.4: Comparison of Pd biosorption between different parts of water hyacinths and different operating conditions

The process is optimized by using dehydrated water hyacinth roots and using the root ends (without stems) as the results in the table below show (the element rates are in mg / L for the initial effluent and in% by mass for the rest of the results, the biomass / volume of effluent ratio is at least 1 g / L):

Label variable Pd Initial effluent mg / L 14 Effluent after biosorption - whole dry hyacinth (5 g / L) mg / L 5.19 Whole Hyacinth extract remaining after biosorption (5 g / L) % mass 1.47

Effluent after biosorption - fresh roots wrung out (5 g / L) mg / L 3.90 Root extract of fresh roots wrung out after biosorption (5 g / L) % mass 2.39 Effluent after biosorption - uncrushed and dehydrated roots (1 g / L) mg / L 7.70 Root extract unground and dehydrated after biosorption (1 g / L) % mass 13.90 Effluent after biosorption - fresh uncrushed roots (1 g / L) mg / L 6.70 Root extract derived from fresh uncrushed after biosorption (1 g / L) % mass 6.60 Effluent after biosorption - uncrushed and air-dried roots (1 g / L) mg / L 3.93 Root extract of uncrushed and air-dried roots after biosorption (1 g / L) % mass 12.62 Effluent after biosorption - stems (without small roots) (1 g / L) mg / L 8.33 Extract derived from the stems after biosorption (1 g / L) % mass 3.64 Extract derived from small roots (without stem) after biosorption (1 g / L) % mass 21.87 Effluent after biosorption - small roots (without stem) (1 g / L) mg / L 0.91 Effluent after biosorption using hyacinth root powder (1 g / L) mg / L 5.39

Table 5: Comparison of Pd biosorption between different parts of water hyacinths and different operating conditions, palladium content.

Example 1.5: Comparison of Pd biosorption of other materials

Other plant materials rich in phenolic acids (wheat straw) and lignin were tested for comparison. These materials have not been functionalized. The results obtained are shown in the table below (the element rates are in mg / L for the initial effluent and in% by mass for the rest of the results):

Label variable Pd Initial effluent mg / L mg / L 14.51 Effluent after biosorption (wheat straw powder 5g / L) mg / L 3.38 Wheat straw extract after biosorption % mass 2.96 Effluent after biosorption (lignin derived from wheat straw 1 g / L) mg / L 1.63 Lignin extract after biosorption % mass 6.67 Effluent after extraction - Heat treated lignin Ig / L mg / L 1.61

Lignin extract heat treated after biosorption 1 g / L % mass 3.26 Effluent after biosorption (pine cone powder) 1 g / L) mg / L 1.09 Effluent after biosorption (water lettuce root powder 1 g / L) mg / L 0.96 Effluent after biosorption (cellulose 1 g / L) mg / L 11.8 Effluent after biosorption (green algae powder Ig / L) mg / L 9.1

Table 6: Comparison of Pd biosorption from other plant materials

The percentages of Pd fixed are lower than those of the dehydrated hyacinth root powder. However, the heat treatment adopted does not completely destroy lignin, unlike cellulose. The "catalytic activity" part is the decisive parameter for assessing the value of these materials of plant origin.

The use of a material of plant origin of different composition (tannin instead of phenolic polymers) is a complementary solution. It leads to catalysts of more conventional composition, namely monometallic. This possibility is illustrated with the coffee grounds.

Label Mass of coffee grounds (g / L) variable Pd content Initial effluent - mg / L 14.46 Effluent after biosorption Ig / L mg / L 12.03 Ash after biosorption - % mass 50.81 Effluent after biosorption 5 g / L mg / L 5.03 Ash after biosorption - % mass 36.50 Effluent after biosorption 5 g / L mg / L 1.05 Coffee grounds washed 3 times with water Effluent after biosorption 5 g / L mg / L 0.72 Ash after biosorption - % mass 59.48

Table 7: Bringing coffee grounds into contact with an effluent

Coffee grounds have remarkable Pd chelating properties. Very high rates of biosorption can be achieved with 5g / L of coffee grounds. Its heat treatment leads to a metal catalyst where Pd is the very predominant element. Its metallic composition is different from that which derives from the roots of aquatic and terrestrial plants. In the case of tannins such as coffee grounds, the heat treatment leads to almost total destruction of the organic matter.

The results obtained with the powders derived from pine cones and water lettuce roots are spectacular: all the Pd is extracted with 1 g of biomaterial, without prior functionalization (entries 8 and 9 of Table 6).

Example 2.1: Recycling of manganese (Mn) and iron (Fe)

Fe and Mn constitute the metallic elements of the chemistry of the future. The first is very abundant, inexpensive and non-toxic. Its catalytic properties are broad: oxidations, Lewis acids and coupling agents. Μη (II, III, IV) constitutes an oxidizing agent which can advantageously replace the reagents and catalysts defective by the REACH regulation. Their recycling is rarely mentioned. However, the discharge of effluents loaded with these metallic species constitutes an environmental problem. Moreover, according to PIPAME, the known and exploitable resources of Mn could be exhausted in about 40 years. Recycling is therefore useful and necessary. It also opens up new opportunities in synthesis as evidenced by the examples presented.

The purification of an industrial effluent is always much more complex and difficult than that of a synthetic laboratory solution.

A study on the biosorption conditions shows that it is possible to extract the two elements Fe and Mn, by adjusting the amount of material of plant origin. With 20g / L of plant material (hyacinth root powder), aluminum, zinc and nickel are fully adsorbed as well.

variable Al It Mg Mn Fe Zn Or Initial effluent mg / L 44.5 214 175 13.3 11.1 3.4 2.1 Effluent after biosorption mg / L 0 209.1 134.5 0.8 0.3 0 0 Table 7: Al, Ca, Mg, Mn, Fe, Zn and h contents i in an effluent before and after setting

contact with a root extract of water hyacinth.

An advantageous process for reducing the amount of biomass is possible by neutralizing the industrial effluent.

Neutral industrial effluent column purification procedure:

A liter of industrial effluent (characterized by a pH between 2.5 and 3.5) was neutralized with sodium hydroxide (2M NaOH) to neutral pH, then was passed through a column containing one of the powder of non-functionalized water hyacinth. After 1 passage at room temperature (30 minutes), the powder is dried at 85 ° C. The dry residue is calcined at 550 ° C to obtain a powder enriched in metals.

The throughput has very little influence on the results. 20 l / h, 5 l / h and 2.5 l / h lead to similar results. Likewise, very low residence times are sufficient: 1 minute for 50 mL of effluent / 12g of biosorbent.

Metal Conc. Initial in effluent (mg / L) Conc. in the effluent after passage 1, (mg / L) Al 4.2 0 It 51.9 81 Fe 7.2 0 Mg 50.5 38.6 Mn 11.4 0.2 Zn 2.3 0 Table 8: Purification of one liter of industrial effluent neutral with 12g of hyacinth powder

non-functionalized

The results show that Al, Fe, Mn and Zn are very strongly or even totally retained by the plant material. The level of Mn is compatible with the rejection standards (0.5 mg / L), the sum Fe + Al, of Zn also (accepted limits: Fe + Al = 5 mg / L, Zn = 2 mg / L).

The following table indicates the amount of biomass (water hyacinth powder) required to biosorb 100% Mn depending on the initial concentration of Mn in the industrial effluent.

Mn content in the effluent mg / L 3 6 9 12 15 18 21 24 Amount of biomass required g 2.3 5 8.6 13 18.5 24 28 30 Table 9: quantity c e biomass required to biosorb 100% c e Mn

In conclusion, the hyacinth root powder used under the conditions described allows Fe, Al, Zn and Mn to be adsorbed simultaneously and meets environmental release standards. (Mn = 0.5 mg / L).

The discharge of effluents loaded with Mn and Fe constitutes an environmental problem.

Example 2.2. Iron recycling

Industrial environments comprising high Fe and Mn contents have been treated with root extracts of dehydrated and ground water hyacinths. These roots are then heat treated at 500 ° C. Once the mineralization has been carried out, the analyzes are carried out by inductively coupled plasma mass spectrometry, or ICP-MS (in English: Inductively Coupled Plasma Mass Spectrometry). With Ig / L of biomass, it is possible to extract more than 95% iron. The results are summarized in the table below and illustrate the possibility of selective extraction of Fe in the presence of Mn.

Label variable N / A Mg Al K It Mn Fe Initial effluent mg / L 13 123 41 2.8 155 9 6.2 Effluent after biosorption mg / L 16 107 34 8 148 7 0.3 Root extract ppm 68848 37871 25342 98207 25342 2288 55790 Root extract % mass 6.88 3.79 2.53 9.82 2.53 0.23 5.58

Table 10: Selective extraction of Fe in the presence of Mn

Regarding calcined root extracts, the accumulation of Mn is low (0.23%). For iron, the quantity is more significant (5.58%), the proportions in the ash are therefore consistent with the very low concentration of metals remaining in the effluent (0.6%). The biosorption is therefore very efficient. The quantity of aluminum in the ashes is not negligible (3.2% for the concentrated effluent and 2.5% for the untreated) because this element has very interesting properties when it is in the form of aluminum chloride (AlCfi). It is a powerful Lewis acid which has many applications in the chemical industry, especially as a catalyst for electrophilic aromatic substitution reactions.

A study on the biosorption conditions shows that it is possible to extract the two elements Fe and Mn, increasing the duration of biosorption or the amount of biomass. With 20g / L of biomass (hyacinth root powder), aluminum, zinc and nickel are also totally adsorbed.

variable Al It Mg Mn Fe Zn Or Initial effluent mg / L 44.5 214 175 13.25 11.14 3.4 2.1

Effluent after biosorption mg / L 0 209.1 134.47 0.82 0.29 0 0 Table 11: Concentration of metals in el ïluent

In conclusion, the hyacinth root powder used under the conditions described allows Fe, Al, Zn and Ni and Mn to be adsorbed simultaneously. It is also possible to sequentially biosorb Fe, Al, Zn, Ni, then Mn. This example shows that Fe can be extracted before and without Mn if the amount of plant material is low.

Example 3: Recycling of Ni

The biosorption was carried out on an effluent comprising nickel in the form of NiSO4 (15 mg / L of Ni). Absorption is carried out with pine cone powder and water lettuce root powder.

Preparation of the pine cone powder: a pine cone is roughly chopped, then washed in 100 mL of iPrOH. After 30 min, the pine cone is filtered, dried at room temperature, crushed and sieved on the sieve with the mesh openings of 1.5 mm. The powder obtained is used in biosorption.

Preparation of water lettuce powder: Lettuce roots are air-dried at room temperature to a stable mass, then crushed and sieved with a sieve with mesh openings of 1.5 mm. The powder obtained is used directly in the extraction of metals.

Procedure: 1 g of material of plant origin is added to 1 liter of a solution consisting of NiSO ₄ (15 mg / L of Ni). The mixture is stirred for 2 h then filtered. The solid is dried at 85 ° C. overnight. The dry solid obtained is then heat treated at 550 ° C. for 6 h in order to obtain the ash enriched in metals.

Conc Initial Ni in the effluent, mg / L Conc. in Ni in the effluent after coming into contact with A (mg / L) Conc. in Ni in the effluent after contact with B (mg / L) 15 <1 <1 Table 12: Nickle extraction with the pine cone powder (A) and the root powder

Example 4.1: Depollution of water contaminated with arsenic water lettuce (B)

An innovative solution for decontanting water polluted with arsemc is proposed. It is based on a bio-inspired solution. The principle consists in reconstituting the natural affinity of arsemc for the oxides of Mn and Fe from the biomasses saturated with these elements during the purification of an effluent which has decontaminated a pyrite quarry effluent. The biomasses are heat treated (550 ° C. for 6 hours) before use.

Procedure for decontaminating pyrite quarry effluents: A vegetable ungine material, for example powder of water hyacinth or powder of pine cones modified by autocatalysed esterification with succinic acid, is placed in a column. An industrial effluent containing Mn (effluents from pyrite quarries) is introduced into this column. The effluent which has been in contact with the material of plant origin is collected in an Erlenmeyer flask. This effluent meets the standards for discharge in Mn and Fe / Al. The plant material comprising mixed oxides (Fe, Mn, Al) is recovered, dried at 85 ° C and heat treated at 550 ° C before being used as a plant filter.

Procedure for decontaminating water comprising arsenic: A plant filter resulting from the purification of the effluent from a pyrite quarry and having been heat treated (550 ° C, 6h), is placed in a column, then are washed with distilled water. A solution comprising arsenic is introduced into this column filled with the vegetable filter. The water that has been in contact with the plant filter is collected in an Erlenmeyer flask. The solution at the column outlet is collected and analyzed in ICP-MS and meets the rejection standards in As.

The quantity of biomass necessary to obtain 1 g of solid residues enriched in metals.

A) Case A: 9.4 g of biomass

B) Case B: 6.7 g of biomass _________________________ _। % mass Al It Fe Mn Zn Case A 0.4 21 1 0.8 0.2 Case B 4 29 0.9 0.8 . 0.3 Table 13: Composition of heat-treated lacmthes root powders and ayan.

used to purify two different quarry effluents of pyrites A and_B

The two compositions differ essentially in% Al, or even Ca. The levels of Mn and Fe are very similar. Remember that the 3 treatments described in the literature and used in the natural environment are: AI2O3, Fe (O) OH, MnO2.

Origin of biosorbent Initial concentration of As, mg / L Final concentration of As, mg / L Flow rate, mL / min Case A 1.5 <0.001 100/20 Case B 1.5 0.04 100/20 Case B 14 0.006 100/60 Case B 14 0.08 100/90 Table 14: summary of the purification of the synthetic effluent from. the Ace with 5g / L of

heat-treated powders derived from biomass used to treat effluents

In this case, the adsorption of As is very sensitive to flow. The slower the flow, the better the biosorption. Cases A and B meet the environmental discharge standards (0.05 mg / L), case A also meets the WHO drinking water standards (0.01 mg / L).

It is therefore possible to directly upgrade a plant filter saturated with Mn / Fe as a filter purifying water contaminated with As. These results are unexpected, since the heat treatment used to generate the ash is at 550 ° C, the manganese present. may be in the form of Mn ⁿⁱ , according to Manganese compounds, Ullmann Encyclopedia of industrial chemistry 7th Ed. It is not the form known to adsorb As, Μηθ2 · The levels of Fe are identical and do not allow to explain these results. A higher% Al decreases the adsorption performance of As, suggesting that aluminum is not in the form of alumina, known for its As adsorption activity.

Given the polymetallic composition of the material of plant origin, mixed oxides may explain such a result. XRD and X absorption studies have demonstrated the presence of a mixed oxide of calcium and manganese in heat-treated Phyto-Mn: Ca2Mn30g. These results show that the passage through a material of plant origin does not lead to a simple juxtaposition of metallic elements, but to a complex mixture different from conventional systems.

Example 4.2. Depollution of a solution comprising phosphates

The same process as that of Example 4.1 is adaptable to phosphate: plant filter resulting from the purification of the effluent from a pyrite quarry and comprising Mn and Fe and heat treated at 550 ° C makes it possible to concentrate 21 mg / L disodium monohydrogenphosphate from a 25 mg / L loaded solution.

Example 5: Zn recycling

Zinc is an essential mineral in many applications. The world's exploitable Zn resources could be exhausted within 17 years (G. Pitron, The war of rare metals. LLL 2018). Developing recycling processes is a topical issue. It is proposed to show how structural materials rich in phenolic acids can solve this key problem. The demonstration is made on industrial effluents corresponding to real, complex, polymetallic cases, and not simple and reconstituted synthetic solutions.

Batch mining effluent purification procedure:

The plant material is added to 1 liter of a solution generated by the infiltration of water into mining galleries that have exploited zinc ore. The mixture is stirred for 2 h then filtered. The solid is dried at 85 ° C. overnight. The dry solid obtained is then heat-treated at 550 ° C for 6 hours to obtain the ash enriched in metals.

Procedure for purification of the same mining effluent in a column:

The plant material is put in a column, washed with water to moisten it. Then, 1 liter of effluent is eluted in a column with a flow rate of 3 1 / h. The mixture is stirred for 2 h then filtered. The purified solution is analyzed by MP-AES. The biomass is dried at 85 ° C overnight, then heat treated at 550 ° C for 6 hours to obtain the metal enriched ash.

Biomass Mass, g / L Final Zn concentration in the effluent, mg / L - - 12.5 PRJ * 3 1 PRJ * 5 0.6 PRJ in column 3 1 PPP *** 5 3

Resin acids *** 5 3 * P RJ - hyacinth root powder ** P PP - pine cone powder *** Resin acids extracted with isopropanol from pine cones

Table 15: summary of the purification of the mining effluent rich in Zn (12.5 mg / L) and Fe (5 mg / L):

With 3 g of water hyacinth root powder, you can purify the mining effluent containing Zn at 12 mg / L. Purified water contains around 1 ppm Zn which is below the authorized discharge standards (2 mg / L). Pine cones and resin acids alone are very close to the acceptable limit value. Their advantage is to immediately retain iron, which is no longer detected after filtration. The crushed pine cones can therefore serve as a vegetable pre-filter.

Example 6: Functionalization of materials of plant origin and biosorption

The affinity of transition metals for phenolic biomaterials varies depending on the chemical structure of the cation to be complexed. So, for example, the affinity of palladium (Pd) to powdered hyacinths, water lettuce and pine cones is exceptional. The situation is very different with ruthenium (Ru), iridum or nickel (Ni). Thus, other tests were carried out after functionalization of biomaterials, in order to increase the affinity of this type of cations for the material of plant origin (biosorbent). This approach is innovative because it leads to valuing common plant raw materials in an original way. The example of lignin is striking: much research is devoted to the depolymerization of lignin and the production of small aromatic molecules. The objective is based on a new type of lignin recovery: its use as an eco-support material for recycling organic synthesis catalysts and decontaminating effluents.

The functionalization of natural phenolic acids is based on the principles of the chemistry of phenols and of acid-derived functions adapted to that of polymers.

A possible functionalization mode is described: it is based on a carboxylation reaction of hydroxyl functions making it possible to introduce a functionalized or non-functionalized ester link. Examples from the literature describe the enrichment of plant materials by the use of citric acid. The method described consists in impregnating the material in water, heating to 60 ° C, then to 100 ° C until the medium is concentrated, then heating to 120 ° C to cause the esterification of the hydroxyl functions of the material via the formation citric anhydride intermediate (B. Zhu et al., J. Hazard. Mater. 153 (2008) 300-308). The process suffers from several limitations: removal of water is difficult and unfavorable to the formation of anhydride; the decomposition of citric acid takes place at a higher temperature (150 ° -170 ° C: Journal of Thermal Analysis and Calorimetry, 20H, Volume 104, Issue 2, pp 731-73) and the formation of citric anhydride is a minor product of the thermal decomposition of citric acid (Biomacromolecules 2007, 8, 3860-3870). The processes described here overcome these limitations by replacing water with green solvents that are easier to remove (alcohols, ideally ethyl acetate), by using a carboxylic anhydride and allowing a high degree of functionalization of the materials. 'vegetable origin. The reaction is controlled in order to limit the formation of water-soluble fractions of no interest in decontaminating the water. Acid anhydrides may or may not be functionalized. They can be cyclic or aliphatic. They make it possible to introduce carboxylic, sulphonic, phosphonic acid, carboxylic ester and amide functions under more efficient conditions. Direct esterification reactions by autocatalysis (without passage through an intermediate anhydride) are also possible, but here again water should be avoided. Different natural polyacids are possible

The direct esterification reactions were carried out by autocatalysis using polyacids, functionalized or not and preferably in a non-aqueous medium. The most effective reactant-catalysts have the following general formula:

R pLjn .COOH HOOC ^ / \ R ^{, / Z} R n = 0.1, 2; R = H, OH, NH ₂ , alkyl, aryl, CH ₂ SR '”, R' = H, COOH, COOR, CH ₂ COOH, NHalkyl, NH-aryl, NAr ₂ , NH ₂ , OH, R” = H , OH, NH-alkyl, NH-aryl, NAr ₂ , NH ₂ .

x

K COOH HOOC ^ cXIR-i R ' ^Z R n = 0.1, 2; X = O, NR (R = H, OH, alkyl, aryl), R '= H, COOH, COOR, CH ₂ COOH, NH-alkyl, NH-aryl, NAr ₂ , NH ₂ , OH, R ”= H , OH, NH-alkyl, NH-aryl, NAr ₂ , NH ₂ .

The functionalization of the plant material is also carried out by acid anhydrides previously prepared or generated in situ at a temperature greater than or equal to 150 ° C.

η = 1, 2; R = H, OH, NH ₃ ⁺ , NR3 ⁺ , alkyl, aryl, P (O) OR'2, S (O) OR ' ₂ , R' H, OH, NH ₃ , NR ₃ , alkyl, aryl, P (O) OR ' ₂ , S (O) OR' ₂ .

n = 1, 2; R = H, OH, NH ₃ ⁺ , NR3 ⁺ , alkyl, aryl, P (O) OR'2, S (O) OR ' ₂ , R' H, OH, NH ₃ , NR ₃ , alkyl, aryl, P (O) OR ' ₂ , S (O) OR' ₂ .

n = 1, 2; X = O, NR '”(R” ^{, =:} H, OH, alkyl, aryl), R'- H, R ”- H, OH.

Examples 6.1: Carboxylation via a previously prepared anhydride: example of succinic acid

3.2 g of succinic anhydride are dissolved in 34 mL of ethyl acetate. The mixture is brought to reflux until complete solubilization of the anhydride, then 5 g of biomass are added to the solution. The suspension is stirred at reflux for 1 hour. The solvent is evaporated off under reduced pressure and the solid is left at 120 ° C. for 1 night. After cooling to room temperature, 50 mL of distilled water is added to the solid and stirred for 15 mm. The mixture is filtered and washed several times with distilled water (200 mL of distilled water for each wash, stirring 15 min before filtration) until neutral pH. The solid is recovered and dried at 85 ° C. for 1 night. Then, the functionalized material is suspended in 100 mL of distilled water and 2M NaOH is added until neutral pH. The solution is filtered and washed several times with distilled water until the colorless filtrate is obtained. The solid is dry at around 85 ° C.

Examples 6.2: Carboxylation by direct esterification and autocatalysis: example of citric acid g of biomass are added in a flask with 4 g of citric acid in 20 mL of anhydrous ethanol. The mixture is stirred for 1 hour at reflux. The solvent is evaporated off under reduced pressure and the solid is placed in an oven at 120 ° C for 1 night. After cooling to room temperature, 50 mL of distilled water is added to the solid and stirred for 15 mm. The mixture is filtered and washed several times with distilled water (200 mL of distilled water for each wash, stirring 15 min before filtration) until neutral pH. The solid is recovered and placed in an oven at 85 ° C for 1 night. Then, the functionalized biomass is suspended in 100 mL of distilled water and 2M NaOH is added until neutral pH. The solution is filtered and washed several times with distilled water until the colorless filtrate is obtained. The solid is placed in an oven at 85 ° C.

Examples 6.3: Carboxylation by direct esterification and autocatalysis: example of glutaric acid g of biomass are added to a flask with 3.2 g of glutaric acid in 20 mL of ethyl acetate. The mixture is stirred for 1 hour at reflux. The solvent is evaporated off under reduced pressure and the solid is placed in an oven at 120 ° C for 8 h. After cooling to room temperature, 50 mL of distilled water is added to the solid and stirred for 15 mm. The mixture is filtered and washed several times with distilled water (200 mL of distilled water for each wash, stirring 15 min before filtration) until neutral pH. The solid is recovered and placed in an oven at 85 ° C for 1 night. Then, the functionalized biomass is suspended in 100 mL of distilled water and 2M NaOH is added until neutral pH. The solution is filtered and washed several times with distilled water until the colorless filtrate is obtained. The solid is placed in an oven at 85 ° C.

Various examples of carboxylation are described in the following paragraph. A basic treatment makes it possible to generate the carboxylates and to reinforce the complexing nature of the biosorbent. Diacids such as succinic and glutaric derivatives are interesting because the carbon number limits the solubilization of carboxylates in water. The yield is greatly improved.

Examples 6.4: Carboxylation using lemon juice

1g of washed coffee grounds is added to 25 mL of freshly squeezed lemon juice. The reaction mixture is gradually heated to 100 ° C and held until the solid is dry. The product is dried at 120 ° C. overnight. Then the solid is washed several times (until pH = 6-7) with distilled water. After washing the biosorbent well with water, 2M NaOH is added until pH = 7, the solid is filtered off and washed several times (until neutral pH) with water. The functionalized biosorbent is dried at 85 ° C. for 12 h, then analyzed by IR. The grafting rate is high, but lower than that obtained by isolated citric acid.

In order to determine the rate of functionalization of the functionalized materials, a titration of the carboxylic acid functions using an aqueous solution of 2M NaOH was carried out. All the data are grouped together in Table 16.

The measurement of the intensities of the bands is made to assess the need or not to functionalize the biomass. A check after functionalization leads to the following data:

Functionalized materials IR data of the C = O band of the COOH group (cm '') IR data of the aromatic ring (cnf ¹ ) Absorbance Difference Ratio (DT) between functional groups C = O / Ar Hyacinth root powder functionalized by succinic anhydride / AcOEt 1680 (□ T = 12.3%) 1513 (□ T = 7.2%) 1410 (□ T = 11.1%) 1.7 L 1 Coffee grounds functionalized by succinic anhydride / AcOEt 1660 (□ T = 2.5%) 1517 (□ T = 1.7%) 1.5 Pine cone powder functionalized by succinic anhydride / AcOEt 1641 (□ T = 2.7%) 1512 (□ T = 2.1%) 1.3 Pine cone bark powder functionalized with succinic anhydride / AcOEt 1607 (□ T = 12%) 1512 (□ T = 7.7%) 1.6 Pine cone powder functionalized by citric acid / EtOH 1613 (□ T = 0.95%) 1511 (□ T = 0.42%) 2.3 Coffee grounds functionalized by 1660 (□ T = 14%) 1515 (□ T = 10%) 1.5

T citric acid / EtOH 1412 (□ T = 13) 1.1

Table 16: IR analysis of plant materials before and after functionalization

It should be noted that the functionalization also results in the formation of a C = O band attributed to the carboxylic ester group formed

Example 6.5: Esterification using simple alcohol

The esterification of the COOH groups of the biosorbent of plant origin can be carried out by a simple aliphatic alcohol such as methanol, ethanol.

Hyacinth root powder (5 g) is suspended in methanol (250 mL), acidified with an acid such as conc H2SO4 acid (1 mL). The reaction mixture is heated at reflux for 12 h, then filtered at room temperature. The solid is washed several times with water (until neutral pH). The functionalized biosorbent is dried at 85 ° C. for 12 h.

Example 6.6: Saponification

Many biosorbents rich in phenolic acids have carboxylic ester functions. In order to increase the number of carboxylic acid functions, a controlled hydrolysis of the ester functions is possible.

Operating mode

10 g of pine cone powder are dissolved in 60 ml of 0.1M aqueous sodium hydroxide. The suspension is stirred for 4 hours at 80 ° C, then cooled to room temperature, filtered, washed with water until return to neutrality, and dried at 85 ° C.

Example 6.7. Transfunctionalization

Certain phenolic biomaterials are naturally rich in carboxylic ester functions. This is, for example, green tea. This property can be exploited to transesterify or transfunctionalize ester groups with polyfunctional ester or amide groups in order to enhance the affinity of the platinoids for biosorbents. Amines, alcohols, aminosulfonates, aminophosphonates and aminoalcohols have been studied.

Example 6.7.L

Green tea powder washed beforehand with hot water (1 g) is suspended in ethanolamine at 110 ° C (10 mL). The reaction mixture is heated at reflux for 6 h, then filtered at room temperature. The solid is washed several times with water. The functionalized biosorbent is dried at 85 ° C. for 12 h.

Example 6.7.2.

Green tea powder (1 g) washed beforehand with hot water is suspended in the mixture of fôrLbutanol and taurine (1g) at 110 ° C (35 mL). The reaction mixture is heated at reflux for 6 h, then filtered at room temperature. The solid is washed several times with water. The functionalized biosorbent is dried at 85 ° C. for 12 h.

Example 6.7.3.

Green tea powder (400 mg) washed beforehand with hot water is suspended in 2-dipicolylamine (4 mL) at 110 ° C (35 mL). The reaction mixture is heated at reflux for 6 h, then filtered at room temperature. The solid is washed several times with 1 water. The functionalized biosorbent is dried at 85 ° C. for 12 h.

Example 8. Recycling of Pd with functionalized biomass

The functionalizations described above are implemented to optimize the recycling of Pd. The different possibilities described above are directly compared.

Batch biosorption procedure:

In an aqueous solution containing 14 ppm of Pd (II), 1 g of biomass is added and the mixture is left to stir for 2 hours. The biomass is filtered, dried at 85 ° C for 12 h and calcined at 550 C.

A) Hyacinth powder functionalized by autocatalysed esterification with 1 citric acid.

B) Hyacinth powder functionalized by autocatalysed esterification with succinic acid.

The following table indicates the concentration of palladium in the aqueous solution after contacting with material A or B.

Conc Pd, mg / L Conc. Initial in the effluent 14 Conc. in the effluent after coming into contact with A 0 Conc. in the effluent after coming into contact with B 0

Table 17: Pd concentration in the effluent after coming into contact with material A or B _L

The modification of the biomass increases the capacity of palladium biosorption. We manage to extract all the palladium from the solution after functionalization. The carboxylation and esterification lead in each case to a total recycling of the Pd.

This approach can be extended to other biomaterials:

A) Coffee grounds functionalized by autocatalysed esterification with citric acid

B) Coffee grounds functionalized by autocatalysed esterification with succinic acid

The following table indicates the concentration in the aqueous solution after contacting with biosorbent A or B.

Pd, mg / L Conc. initial in the effluent 14 Conc. in the effluent after coming into contact with A 0 Conc. in the effluent after coming into contact with B 0

Table 18: Pd concentration in the effluent after contact with material C or D.

The modification of the coffee grounds by the reaction improves the recycling of Pd (II). It is more than doubled in each case. Functionalizations by carboxylation (A, B) are very effective. In the 2 cases described, the extraction of Pd is complete.

The best results with functionalized biomass were studied with higher palladium concentrations to test the limits of the process:

A) Biosorption of Pd in different concentrations with 1 g of hyacinth powder functionalized by autocatalysed esterification with citric acid / EtOH.

Conc. Initial After biosorption 14 mg / L 0 30 mg / L 0 44 mg / L l mg / L Table 19: Bisorption of Pd with valley re of hyacinth functionalized by esterification

autocatalyzed with citric acid / EtOH

B) Biosorption of Pd in different concentrations with 1 g of hyacinth powder esterified with methyl alcohol.

Conc. Initial After biosorption

14 mg / L 0 30 mg / L 5 mg / L

Table 20: Bisorption of Pd with hyacinth powder esterified with methyl alcohol

The extraction of palladium with esterified biomass remains efficient. We can accumulate 25 ppm palladium under these conditions.

In order to be able to transpose the results to an industrial scale, we performed column extraction (and no longer batch) on a solution of 40 mg / L of Pd with 1 g of biomass (hyacinth powder esterified with citric acid) per liter of effluent.

Column biosorption procedure:

g of biomass (hyacinth powder functionalized with citric acid is placed in the column.

The synthetic effluent (1 L) containing 40 mg of Pd is passed through the column three times. The passage time of 1 L of solution is 35 min.

Pd, mg / L Conc, initial 41 Passage 1 0 Passage 2 0 Passage 3 0

Table 21: Biosorption of Pd with hyacinth powder functionalized with 1 citric acid

The complexation of palladium is remarkable. 41 ppm Pd, or 100% metal, is fixed on the plant material after the first pass. We can see that a single pass is sufficient to absorb all the palladium that is not desorbed after a second and even after a third pass.

Example 9.

Ru, Ir, Ni are naturally present in an ore rich in Pd. Knowing how to selectively absorb Pd in the presence of these other elements can be very useful. Functionalized phenolic acids make it possible to obtain very good overall yields on a Pd, Ru, Ir mixture.

Initial conc Conc Initial conc Conc Conc Final conc Pd mg / L final Ru mg / L final initial Ir Ir mg / L

--- Pd mg / L Ru mg / L mg / L 15 0 15 15 15 15

Table 22: Depollution of Pd, Ru and Ir

Example 10. Recycling of Ni

The biosorption of Ni is an interesting and useful case. In addition, the toxicity of Ni implies a total extraction, if one wishes to be in accordance with the WHO standards relating to the quality of drinking water or the discharge standards, themselves very demanding for this. element. This is why the functionalization of biosorbents has been studied.

Absorption is carried out with different biosorbents (coffee grounds, hyacinth root powder, water lettuce root powder, pine cone powder, green algae for comparison) chemically functionalized.

Batch Ni biosorption procedure:

g of functionalized biosorbent is added to the solution of NiSO4 * 6H2O (0.063 g / L). The mixture is stirred for 2 h then filtered. The solid is dried at 85 ° C. overnight. The resulting dry solid is then heat treated at 550 ° C for 6 hours to obtain nickel enriched ash.

A) Coffee grounds functionalized by autocatalysed esterification with citric acid (COONa form)

B) Hyacinth root powder functionalized by self-catalyzed esterification with 1 citric acid (-COONa form)

C) Non-functionalized green algae

Label variable Or Conc. initial Ni in the effluent mg / L 12 Conc. in Ni in the effluent after coming into contact with A mg / L 0 Conc. in Ni in the effluent after coming into contact with B mg / L 0 Conc. in Ni in the effluent after coming into contact with C mg / L 3.73

Table 23: Ni concentration in the effluent

The functionalization of the biomass leads to the formation of a biosorbent effective to remove traces of Ni in the solution if new carboxylic groups are introduced, in particular in the COONa form. For comparison, we performed 1 extraction with green algae. This biomaterial is chosen because it is rich in alginic acid which is known to complex nickel well thanks to the carboxylic group and can be compared with biosorbents functionalized with citric acid. On the other hand, we observe the average efficiency of algae due to the solubility of alginic acids in water, which causes the complex to pass through the filtrate. In addition, the mixture is difficult to filter. This result shows the interest of 5 phenolic acids whose carboxylate groups induce a strong complexing power at neutral pH and the carbon structure makes the solid materials insoluble in water.

Study of the different Ni biosorption parameters

We have studied the maximum amount of Ni that can be extracted by the different biosorbents according to their mode of functionalization.

Nature of biomass Functional condition m materia u m material u (formCOONa) V (2M NaOH) / g of biomass Functionalization rate (mol (NaOH) / g of biomass) Concentration of the metallic solution Biosorption capacity, mg / g biomass pH of biomass after neutralization we Hyacinth root powder Succinic anhydrid + EtOH 5g 4.3g 0.4 mL / g 0.0008 mol / g 40 mg / L 29 mg / g 7 Hyacinth root powder Succinic anhydrid + AcOEt 5g 4.2g 0.72 mL / g 0.0014 mol / g 40 mg / L 32 mg / g 7 Root powder Succinic anhydrid 5g 4.2g 0.72 mL / g 0.0014 mol / g 1.024 g / L 51 mg / g 7

hyacinth | e + I I AcOEt | J | | Anhydrid | Powder I e π 72 uprooted _o ^J - ^J glutaric 5 gj, 4g of ^{mL /} g + AcOEt hyacinth 0.0007 40 28 mg / g 7 mol / g mg / L Anhydrid III Marcs of e „. 5g ⁴ ' ⁷ gt, succinic coffee mu / g e + EtOH 0.00064 40 22 mg / g 7 mol / g mg / L I Anhydrid | e 0.28 succinic marks 5g 5.1g coffee ^{mL /} g e + 1 1 AeOEt JJJ 0.0014 40 1. ₇ 31 mg / g 7 mol / g mg / L | Anhydrid | e 0.28 succinic marks 5g 5.1g coffee ^{mL /} g e + AcOEt 0.0014 1.024 33 mg / g 7 mol / g g / L Anhydrid I | Apple 5g 3.4g 0.2 mL / g succinic pine e + EtOH 0.0008 40 21 mg / g 7 mol / g mg / L Anhydrid 1 1 e Apple 0.88 succinic 5g 5.7g pine mL / g e + AcOEt 0.0011 40 30 mg / g 7 mol / g mg / L | | Anhydrid | I Bark e 5g 3.6g 0.7 mL / g succinic pine e + 0.0013 40 1 30 mg / g 7 mol / g mg / L

AcOEt Pine cone Citric acid + EtOH 5g 5g 0.8 mL / g 0.0016 mol / g 40 mg / L 30 mg / g 7 Pine cone Citric acid + H ₂ O 5g 5.8g 0.8 mL / g 0.0017 mol / g 40 mg / L 25 mg / g 10 Coffee grounds Citric acid + H ₂ O 5g 5g 0.8 mL / g 0.0016 mol / g 94 mg / L 29 mg / g 7 Coffee grounds Citric acid + EtOH 5g 5g 0.9 mL / g 0.0018 mol / g 94 mg / L 38 mg / g 7

Table 24: Study of the various Ni biosorption parameters

Five important parameters are highlighted: the carboxylate and non-carboxylic form, a neutral biosorption pH, the agents and conditions of functionalization, the nature of the 5 ecomaterials. Biosorbents rich in sodium carboxylate are very effective and can biosorb up to 55 mg of Ni per Ig of biosorbent (case of hyacinth powder esterified with citritic acid in an ethanolic medium).

Contrary to the work described in the literature (B. Zhu et al., J. Hazard. Mater. 153 (2008) 300-308), carboxylation with citric acid does not involve the formation of an intermediate anhydride and is not an oxidation reaction (Leyva-Ramos et al., Sep. Purif. Tech. 45 (2005) 41-49). Prior preparation of this anhydride results in such a high degree of functionalization that the functionalized carbon skeleton becomes soluble in water during biosorption.

On the other hand, an autocatalyzed esterification reaction, without water, with a polycarboxylic acid whose first acidity has a pKa equal to or less than 4, or the use of an anhydride less rich in carboxylic units in a non-protic medium are effective. . Functionalization with succinic, maleic, phthalic and dicarboxylic diclohexane anhydrides in ethyl acetate leads to very similar results on the three types of biomass studied: hyacinth powder, coffee grounds and apples and pine bark

To prove the generality of the nickel extraction process, we performed the biosorption in a column filled with biomass, and no longer in a batch.

Example IL Extraction of Ni with hyacinth powder functionalized with citric acid by a column-type process

Column biosorption procedure:

g of biomass (hyacinth powder functionalized with citric acid) is placed in the column. The synthetic effluent (10 L) containing 40 mg / L of Ni is passed through the column twice. The passage time of 10 L of solution is 45 min.

The initial Ni concentration in the effluent is 40 mg / L, after one passage it is 2 mg / L.

Complexation is always effective, 38 mg of Ni are fixed on the biomass. A single pass is sufficient to absorb 95% of Ni.

Example 12. Biosorption of Manganese

Plant derivatives rich in phenolic acids are good Mn biosorbents if they are suitably functionalized. They can be used again in synthetic chemistry, especially in oxidation reactions.

Example 12.1 Synthetic solution

MnSO ^ biosorption procedure:

g of hyacinth root powder functionalized with citric acid is added to 1 L of MnSO ₄ solution (24 mg / L, at neutral pH). The mixture is stirred for 2 h then filtered. The solid is dried in an oven at 85 ° C. overnight. The dry solid obtained is then heat treated at 550 ° C. for 6 h in order to obtain the ash enriched in manganese.

Label variable Mn Initial effluent mg / L 23.44 Effluent after biosorption mg / L 0.4 Ashes % mass 18

Table 25: Mn concentration

The functionalized biosorbent is very effective in purifying manganese-laden effluents. Thanks to this process, we obtain manganese levels lower than those set by the regulations.

To verify the general interest of this result, it was implemented from industrial effluents resulting from the extraction of pyrite, that is to say on with acidic media, rich in Mn, but of composition polymetallic.

Example 12.2 Industrial effluent

1g of plant material was used for IL effluent using two processes: batch and column. The results are just as effective despite the plurimetallic composition of the medium.

Example 24. Purification of the neutral industrial effluent with functionalized biomass (hyacinth powder functionalized with citric acid / EtOH)

One liter of industrial effluent (pH = 2.5-3.5) is neutralized with sodium hydroxide (2M NaOH) to neutral pH, then it is eluted on a column containing 1 g of functionalized biomass (root powder of hyacinth functionalized with citric acid). After 1 passage at room temperature (30 minutes), the powder is dried at 85 ° C. The dry residue is calcined at 550 ° C to obtain a powder enriched in metals.

We observe a partial depollution of the effluent with 1 g of biomass per liter, because all the metallic elements are biosorbed. To obtain complete purification of the effluent, 8g of functionalized biosorbent (powder of hyacinth root functionalized by self-catalyzed esterification with citric acid per liter of industrial effluent should be used.

Esterified water hyacinth roots Esterified pine cones Esterified coffee grounds Conc. initial mg / L Conc. final (1 Pass) mg / L Conc. initial mg / L Conc. final (1 Passage) mg / L Conc. initial mg / L Conc. final (1 Passage) mg / L Al 18.6 0 4.3 0 2.5 0 Fe 4.4 0.3 8.2 1 3.8 0.3 It 218 208 65.5 14 113 51.5 Mg 179 147 59 16 23 3.0 Or 1.3 0 0.4 0 0 0 Zn 2.5 0 3 0 0.3 0 Mn 11.7 1.7 11.4 1.6 10 1.6

Table 26: purification of industrial effluents from the pyrite quarry

The purification of the effluent is very efficient. Less than 1 ppm of Fe, Al and Mn remains after the first pass through the column. We can see that one pass is sufficient to effectively purify the industrial effluent. Unlike non-functionalized materials, all metallic elements are retained (Al, Fe, Ni, Zn, Mn) but also Ca and Mg. This result can be generalized to the different types of functionalized materials.

It can also be easily optimized by using 2g of biomass per liter of effluent to be treated.

Conc. initial, mg / L Passage 1, mg / L Al 3.1 0.4 It 58.2 29.6 Fe 1.9 0.5 Mg 37.8 27.6 Mn 9.1 0.8 N / A 192.3 242.7

Table 27: Purification of neutral industrial effluent with functionalized biomass (hyacinth powder functionalized with citric acid)

Example 13. Recycling of rare earths

The growing importance of and access to the resource are difficult geo-economic issues. The study of simple and effective recycling techniques is evident for various rare earths: Sc, Ce, Yb, Eu ...

Example 13.1. Extraction of scandium with hyacinth powder functionalized with citric acid

The hydrated Sc (NO ₃ ) ₃ (0.072g) is dissolved in 1 L of water. It is very weakly retained by biosorbents such as the roots of water hyacinth. On the other hand, the biosorbent capacities of Sc are improved after functionalization. The initial Sc concentration in the effluent is 26 ppm, after extraction it is 5 ppm.

The carboxylation of the biomaterial allows an adsorption capacity of 21 mg / L to be obtained from an initial concentration of 26 mg / L.

Example 13.2. Extraction of scandium in the presence of excess Ni with hyacinth powder functionalized with citric acid

Scandium is often mined from other ores that must be separated. It is for example Ni.

- Batch process

To study the ability of biomass functionalized with citric acid to selectively retain scandium over nickel, we prepared a synthetic effluent with concentrations of Sc = 25 mg / L and Ni = 72 mg / L. the separation is carried out in batch.

We can see the functionalized biomass selectively extracts scandium over nickel, even if the latter is in excess. By comparing the result with the extraction of scandium without nickel, we can see that the biomass accumulates around 20 ppm of scandium which is comparable with the scandium / nickel mixture test where 20 ppm of scandium were fixed and the sites The remaining complexing agents fixed the nickel without replacing the scandium with nickel.

- Column process

To mimic the transformation of effluent purification at the industrial level, we considered purification on a column filled with carboxylated biomass. Knowing that the concentration of scandium in the existing ores is very low, we prepared the solution of nickel and scandium with the ratio 112 ppm of Ni to 2 ppm of Sc. The goal is to see if the scandium remains fixed on the column in the presence of a large excess of nickel, which makes it possible to enrich the biomass with scandium after several passages of effluent with a low concentration of scandium.

0.6 g of biomass (hyacinth powder functionalized with citric acid) is placed in the column. The synthetic effluent (0.6 mL) containing 112 mg / L of Ni and 2.3 mg / L of scandium is passed through the column three times. The residence time is 10 min.

--- Nickel, mg / L Scandium, mg / L Column process Conc, initial 112 2.3 Passage 1 68 0 Passage 2 64 0 Passage 3 64 0 Batch process Conc, initial 72 25 Passage 1 51 ⁴

Table 28: Ni and Sc concentrations

The result obtained is spectacular: it shows a fast, simple, efficient and bio-based process which makes it possible to purify the industrial effluent loaded with nickel and scandium and at the same time to preferentially extract the scandium. This is a new method for enriching biomass with this rare and precious metal. It should be noted that the scandium and the nickel remain fixed on the biomass and are not eluted even after the third passage. Therefore, a single pass through a column is sufficient. Passages 2 and 3 show that there is no desorption. Complexation with biomass is easily extendable to other rare earths such as Ce, Yb and Eu.

Example 13.3. Recycling of Ce

Complexation with biomass is easily extendable to other rare earths like Ce. A cerium solution at a concentration of 32 ppm was prepared. The extraction was performed with hyacinth root powder functionalized with citric acid. The concentration of cerium in the effluent before extraction with hyacinth powder functionalized with citric acid is 32 mg / L, after extraction it is 0.8 mg / L.

Almost all of the cerium is complexed by the functionalized biomass.

Example 13.4. Recycling of Ytterbium

The biosorption is studied with a catalytic solution of Yb (NO3) 3 pentahydrate at 16 mg / L of ytterbium (Yb) and the results of this analysis are described below. The chosen biosorbent is coffee grounds functionalized with citric acid. The concentration of Ytterbium in the effluent before extraction with coffee grounds functionalized with citric acid is 16 mg / L, after extraction it is 1.0 mg / L.

The functionalized biomass is capable of concentrating more than 15 mg of Ytterbium.

Example 13.5. Recycling Europium

The biosorption is studied with a catalytic solution of Eu (NO3) 3 hydrate at 13 mg / L of europium (Eu) and the results of this analysis are described below. The chosen biosorbent is coffee grounds functionalized with citric acid. The europium concentration in the effluent before extraction with coffee grounds functionalized with citric acid is 13 mg / L, after extraction it is 0 mg / L

All of the europium in this concentration is biosorbed with the functionalized biomass.

Example 14. Cu recycling

The extraction was carried out with coffee grounds functionalized with citric acid according to the ethanol process.

The biomass (coffee grounds functionalized with citric acid / EtOH) is placed in a solution of (Ζη (ΝΟ ₃ ) 2 * 3Η ₂ Ο for 1 liter of solution. The suspension was stirred at room temperature, then filtered and the solid is dried in an oven at 85 ° C.

Extraction of copper with coffee grounds functionalized with citi ic acid

Biosorption time Number of biomass / L Conc, initial Cu, mg / L Conc. final Cu, mg / L 2 hrs 1 g 15 0 2h 1 g 101 54 5 days 2.5 g 315 186

Table 29: Cu recycling

The data are superior to those of the literature: Int. J. Approx. Sci. Technol. (20 L) 10: 611-622, Cerino-Cordova et al. 129 mg of copper were accumulated by the biomass in 5 days, which shows a high capacity for extracting functionalized coffee grounds.

Example 15. Recycling of Co

Cobalt is part of the strategic elements for two reasons: it is very useful in green technologies and could use up between 22 (increase of 10% of its consumption) and 57 years (current rate) with regard to profitable resources. The possibility of recycling is therefore relevant. In addition, Co has been regulated by REACH as a carcinogenic and problematic element.

The materials of plant origin of the invention respond to this double problem. Thus, for example, the extraction of Co (NO) ₂ * 6H ₂ O with 1 g / L of powder of hyacinth roots modified with succinic anhydride in AcOEt makes it possible to recover 27 mg / 1 of Co.

Example 16. Recycling of Pb

A lead solution was prepared from Pb (NO3) ₂ . The extraction was carried out with coffee grounds functionalized with citric acid / EtOH.

Extraction of lead with coffee grounds functionalized with citric acid

Biosorption time Quantity of biomass / L Conc, initial Pb, mg / L Conc. final Pb, mg / L

2h 1 g 15 0 2 hrs 1 g 142 86 5 days 1.25 g 213 46

Table 30: Extraction of lead with coffee grounds functionalized with citric acid The data are superior to those in the literature: Int. J. Approx. Sci. Technol. (2013) 10: 611-622, Cerino-Cordova et al.

1g of biomass extracts 56 mg of lead in 2 hours. 170 mg of lead were accumulated by 1.25 g of biomass in 5 days, which shows a great capacity for extracting lead with functionalized coffee grounds.

Example 17. Recycling Cd

A solution of cadmium at a concentration of 15 ppm was prepared from Cd (NO ₃ ) 2 * 4H ₂ O. The extraction was carried out with 1 g of coffee grounds functionalized with citric acid / EtOH. The cadmium concentration in the effluent before extraction with coffee grounds functionalized with citric acid / EtOH is 15 mg / L, after extraction it is 0 mg / L.

All of the cadmium is absorbed by 1 g of biomass in 2 hours.

The following examples show the organic synthesis reactions carried out according to the process of the invention.

Example 15. Coupling reactions with materials having fixed Pd.

The recycled catalytic systems are called Phyto-Pd.

Preparation procedure for preparing the material having fixed Pd (Phyto-Pd):

23.4 mg of ash (coffee grounds) enriched in palladium (54% palladium) are diluted in 3.25 mL of 6N HCl acid and heated at reflux for 6 h. After returning to room temperature, filtration and concentration under reduced pressure, 44 mg of a hygroscopic orange-brown powder is obtained (20.5% palladium).

Example 15.1: Coupling reaction between heterocyclic brominated derivatives with boronic acids (Suzuki reaction). The Suzuki reaction can be carried out in water, butanol or a mixture of water / glycerol or butanol / glycerol.

Boronic acid Heteroaryl or aryl bromide Biosorbent used T (h) Solvent Conversion / O ^Br Hyacinth root powders 2 Glycerol 92% PL ^X S ^ ^Br Hyacinth root powders 2 nBuOH 73% PL ^Br Hyacinth root powders 2 H ₂ O / nBuOH (9/1) 85% B (° ^h ) ₂ , Br ί J N Lignin 2 H ₂ 0 75% Br Î J NOT Hyacinth root powders 2 h ₂ o > 99% PL Br - ^ \ g / ^ Br Hyacinth root powders 2 nBuOH 39% (monocoupling = 56% dicoupling = 44%) Cl f T F ^^^^^ Br Hyacinth root powders 2 Glycerol / nBuOH > 99%

Table 31: Results of coupling reactions

Note the last example in the table above, since it corresponds to the synthesis of a key intermediate in bixafen. The reaction is quantitative in two hours, without adding any ligand, phosphine or particular additive. The catalyst can be recycled at the end of the reaction. Pd is reduced in situ to black Pd by glycerol. It is isolated by filtration, introduced into a solution of 1M nitric acid. Functionalized hyacinth powder allows quantitative recovery of Pd in two hours and regeneration of Phyto-Pd by the heat treatment / HCl activation sequence. The coffee grounds are just as effective. These results can be advantageously compared to those described in the literature (WO 2015/011032 A1, PCT / EP2014 / 065463) where the process requires a very particular phosphine: ((LBu) 2PhPH) BF4, a liganded Pd: Pd (0.12 mol%), the reaction lasts 13 h and the catalyst cannot be recycled. Finally, the yield is lower (86%).

General experimental protocol for the Suzuki reaction

Aryl halide (1.25 mmol, 1 equiv.), Phenyl boronic acid (1.3 potassium carbonate (1.5 mmol, 1.2 equiv.) And 0.1 mol% of catalyst mmol, 1.1 equiv.), Pd base (PhytoPd) are put into a flask. 2.5 mL of solvent is added and the suspension obtained is placed under argon. The reaction mixture is stirred at 95 ° C for 2 h. After 2 h the mixture is cooled. The product is extracted with ethyl acetate and washed with water. The conversion is determined by GC / MS with dodecane as an internal standard.

Entry 1 was made on the scale of 20.4 g of 2-bromothiophene, i.e. 111 mg of Phyto-Pd (0.125 mmol of Pd). This is an interesting case of homogeneous catalysis, Phyto-Pd is completely soluble in the coupling solvent. The catalyst was recycled and reused by the catalyst system in the same reaction. The procedure is based on filtering the Pd formed at the end of the reaction and placing it in aqueous phase at pH = 2.5 using nitric acid. After stirring for 2 hours, the results obtained are spectacular: 84% Pd is re-extracted by the powder of water hyacinth roots. After transformation of the root extracts according to the standard process, the catalytic activity of the regenerated Phyto-Pd is retained.

Liquid phases (mg / L) Pd Aqueous phase resulting from the reaction 0 Organic phase resulting from the reaction 0 Effluent before biosorption 13.2 Effluent after biosorption 0.01 Solid phase (% mass) Pd Phyto-Pd 13.8

Table 32: Mineral composition of solids and solutions invoked in the recycling of palladium (MP-AES analyzes (% mass for solids, mg / L for liquid phases!

The process can be generalized to other heterocyclic halogenated derivatives in glycerol.

It is also possible to carry out the transformations with butanol in the case of non-hydrophilic brominated derivatives (bromothiophene) or in water with nitrogenous heterocycles (bromopyridine). The returns are comparable. These reactions are therefore remarkably efficient, simple to implement and economical (no ligand, no additive) and totally eco-compatible (green solvents and recyclability of Phyto-Pd.

Likewise these catalysts can promote couplings between boronic acids and heterocyclic brominated derivatives. Again, no ligand is needed. Green solvents lead to very good yields.

+ Ar-B (OH) ₂

It is thus possible to couple two thiophenes together, which opens up access to the conductive compounds.

The Suzuki heterocyclic series reaction can also be carried out using PhytoPd recycled by biosorption with coffee grounds. The reaction is carried out in 1 water with a yield of 97%.

Experimental protocol for the Suzuki reaction in water

3-Bromopyridine (4.75 mmol, 1 equiv.), Phenyl boronic acid (5.23 mmol, 1.1 equiv.), Potassium carbonate (5.7 mmol, 1.2 equiv.) And 0 1 mol% of catalyst based on Pd (20.1% by mass of Pd in the catalyst) are placed in a flask. 9.5 mL of solvent is added and the suspension obtained is placed under argon. The reaction mixture is stirred at 95 ° C for 2 h. After 2 h the mixture is cooled. The product is extracted with ethyl acetate and washed with water. The 97% conversion is determined in GC / MS with dodecane as an internal standard.

Example 15.2: Reaction of iodobenzene with methyl acrylate (Heck reaction) o

Iodobenzene (1.4 mmol, 1.4 equiv.), Potassium carbonate (1.3 mmol, 1.3 equiv.), 0.5 mol% of Phyto-Pd catalyst (19% by mass of Pd in the catalyst ) and methyl acrylate (1 mmol, 1 equiv.) are dissolved in gamma-valerolactone (2 mL) under argon at room temperature. The reaction mixture is heated at 120 ° C for 4 h. After 4 h, the reaction is cooled and analyzed in GC / MS with dodecane as an internal standard. The conversion is total. 93% of monoadduct are observed and 7% of diadduct.

The reaction is compared with commercial catalysts such as PdCl ₂ and Pd (OAc) 2- The conversion is complete in both cases, but the ratio between the monoadduct and the diadduct is 80/20 and 87/13 respectively. This difference shows that the reaction with Phyto-Pd is more selective compared to the monocoupling product.

Using bromobenzene, only the monoadduct is observed.

Another Heck reaction, below, makes it possible to demonstrate a much higher percentage of conversion with the bio-based catalyst compared to the commercial catalyst.

Pd catalyst (0.05mol%)

K _z CO _3/140 ° C

Catalyst Time % conversion Phyto-Pd 15 mins 74 K ₂ PdCl ₄ 15 mins 53 Phyto-Pd 30 mins 96 K ₂ PdCl ₄ 30 mins 82 Tab water 34: Results

Example 15.3: Sonogashira reaction

With the recycled Phyto-Pd, the coupling of Sonogashira can be carried out without ligand and without copper salts. The industrial example of butyn-3-ol and 4‘-hydroxy-3'-iodo-biphenyl-4carbonitrile coupling illustrates the potential of Phyto-Pd in this type of reaction.

I

In 100 ml of a 50/50 glyecrol / butanol mixture, 0.05 mol of iodine derivative, 0.1 mol of butyn-3ol are added in the presence of 0.1 mol of K2CO3, and of Phyto-Pd derived from water lettuce (0.5 mol% Pd). The reaction medium is heated to 100 ° C. After 4 h, the reaction is cooled and analyzed in GC / MS with dodecane as an internal standard. The conversion is total.

This result is particularly interesting because it is a key step in the industrial synthesis of 1ΆΒΤ-239, an antagonist of the histamine H3 receptor. It can be advantageously compared with the data in the literature which describe liganded palladium catalysts (example: PdCl ₂ (PPh3) ₂ complex) in the presence of copper salts (Cul): Organic Process Research Development 2005, 9 (1), 45-50), which additionally requires larger amounts of Pd (1 mol% in the previous reference).

The Sonogashira reaction catalyzed by a Phyto-Pd can be extended to the synthesis of Ji-conjugated polymers, such as polyarylenes, polyphenylacetylenes. Again, copper salts and the introduction of ligands are not helpful. It is about easy and efficient access to the polymers used in OLEDs.

nX — Ar ¹ —X + nH ---- Ar ² --- = - H

Phyto-Pd T \ - Ar ¹ ---- Ar ² --- == -) Example: X = I, Ar ^{1 =} Ar ² = Ph

In 100 ml of a 50/50 glycerol / butanol mixture, 0.1 mol of 1,4-diiodobenzene, 0.1 mol of 1,4-diethynylbenzene are added in the presence of 0.1 mol of K ₂ CO3, and of Phyto-Pd derived from pine cone (0.5 mol% Pd). The reaction medium is heated to 100 ° C. After 8 h, the reaction is cooled and analyzed by NMR and IR showing the formation of polycondensation products. With phenylacetylene, the conversion is complete after 2 h of reaction. This result is advantageously compared with that of Yang (J. Org. Chem. 2005, 70, 391-393) who expects 80% yield after 24 h and 1% Pd.

Example 15.4: Reducing chemistry of Pd (II)

Example 15.4.1: Reduction of an enone with the ash of Phyto-Pd

The enone (2.5mmol, 1 equiv.) And the Phyto-Pd (resulting from the controlled heat treatment of the roots of water hyacinths) (0.15 equiv.) Are suspended under argon in degassed THF (2 mL). Formic acid (5.0 mmol, 2 equiv.) Is added and the resulting mixture is refluxed. After 3 h, the mixture is filtered through dicalite and concentrated under reduced pressure. A yield of 85% is obtained in ketone. It is important to note that the reaction does not work with Pd oxide. By hardening the conditions (duration, catalytic load), the percentage of alcohol becomes predominant.

Example 15.4.2: Isomerization of an exocyclic double bond of 2-cyclopentenone

R = alkyl, H

Cyclopentenone (Immol; 1 equiv.) Is added to 0.1 mol% of Phyto-Pd catalyst (20% by mass of Pd in the catalyst), then the mixture obtained is stirred for 16 h under argon at room temperature. The reaction mixture turns dark black. After stirring overnight, the composition of the reaction mixture is analyzed in GC / MS. The conversion to product bearing an endocyclic double bond is 52%.

Example 16: Bio-sourced chemistry of iron (Fe):

Procedure for preparing the material having fixed iron (Phyto-Fe).

400 mg of ash (hyacinth root powder) enriched in iron (2% iron) are diluted in 55.5 mL of 6N HCl acid. The mixture is heated at reflux for 6 h. After returning to room temperature, filtration and concentration under reduced pressure, 430 mg of a hygroscopic yellow powder are obtained (1.3% iron).

Example 16.1: General protocol for the oxidation of benzyl alcohol to aldehyde with Phyto-Fe without ligand:

Phyto-Fe (20 mmol, 2 mol%) is added in 1 mL of H2O and stirred for 20 min to obtain a clear yellow solution. After addition of benzyl alcohol (1 mmol), the reaction mixture is stirred vigorously, then ΙΉ2Ο2 (30% in water, 2 mmol, 0.2 mL) is added dropwise over 10 min using a syringe pump at room temperature. The reaction mixture is stirred for 3 h, then the aldehyde is extracted with ethyl acetate and analyzed in GC / MS with dodecane as an internal standard. A yield of 35% is obtained.

Example 16.2: General protocol for the oxidation of benzyl alcohol to aldehyde with Phyto-Fe activated by a diazotized ligand:

The Phyto-Fe (20 mmol, 2 mol%) and the ligand (20 mmol, 2 mol%; for example phytophytin) are added in 1 mL of H ₂ O. The mixture is stirred for 20 min to obtain a solution clear yellow. After the addition of benzyl alcohol (1 mmol) in the solution, the reaction mixture is stirred vigorously then H2O2 (30% in water, 2 mmol, 0.2 mL) is added dropwise over 10 min to using a syringe pump at room temperature. The reaction mixture is stirred for 3 h, then the aldehyde was extracted with ethyl acetate and analyzed in GC / MS with dodecane as internal standard. A yield of 59% is obtained.

An innovative recovery of iron was carried out with the biomaterial richest in Fe.

Label Al It Fe K Mg Mn N / A Zn Hyacinth root powder ppm 24626 56187 55690 94899 37871 2343 68848 1451 % mass 2.46 5.62 5.57 9.49 3.79 0.23 6.88 0.15

Table 35: Metal contents

The root extracts were heat-treated at 550 ° C., then activated with 6N HCl at reflux for 6 hours. After concentration of the reaction medium, the yellow solid obtained, called Phyto-Fe, was tested in unusual SEAr reactions.

Example 16.3. Unusual oxidative halogenations and SEAr (nitration, thiocyanation)

A Phyto-Fe comprising 0.05 mol of iron, in the presence of an equimolar amount of sodium (or potassium) bromide and anisole are heated at 80 ° C overnight in the presence of 200 mg of montmorillonite K10.

The monobromination product is obtained with a yield of 74%. This result is remarkable, because bromination is possible without dibroma. It is particularly surprising, because from a thermodynamic point of view, Fe (III) is not sufficiently oxidizing to oxidize a bromide to dibroma. It should also be noted that the solid support is not silica, but montmorillonite which does not pose the same toxicity problems.

This bromination method is unique based on data from the literature. The table presented below makes it possible to highlight the advantage of the technology presented: they are based on the use of a non-noble catalyst, easy to access, without dangerous co-oxidants, without solvents, without silica and with a direct process that is very easy to implement, and using bio-sourced and sustainable materials. Conventional methods require the dibroma (irritant) in the presence of Lewis acids or NBS, which generates a toxic imide. The examples given below are based on the use of NaBr, in the presence of complex catalysts or compounds of noble metals, oxidants and toxic solvents. A comparative bibliographic analysis proves that the proposed method is a real progress in the field Journal of Organic Chemistry, 67 (13), 4487-4493, 2002; Eur. Pat. Appl. 1138657, 2001; Tetrahedron Letters, 31 (14), 2007-10, 1990; Eur. Pat. Appl., 1138657, 2001; Bulletin of the Korean Chemical Society, 23 (5), 773-775, 2002; Synthetic communications, 31 (19), 2995-2963, 2001; Journal of Chemical Research, (6), 366-368, 2006; Huaxue Yu Shengwu Gongcheng, 29 (11), 47-49, 2012; Catalysis Science & Technology, 5 (10), 4778-4789, 2015; Journal of Molecular catalaysis A:

Chemical, 371, 56-62, 2013; Chemical, 371, 56-62, 2013 ChemSusChem 6 (8) 1337-1340, 2013; Catalysis Letters, 137 (3-4), 190-201, 2010; Green Chemistry, 8 (10), 916-922, 2006; Synthetic communications, 28 (8), 1463-1470, 1998; Synthesis (2), 221-223, 2006; Tetrahedron letters, 44 (49), 8781-8785, 2003; e-EROS Encycl. of Reagents for Organic Synthesis 1-9, 2006; Advanced Synthesis & Catalysis, 351 (11 + 12), 1925-1932, 2009).

It should be noted that it is possible to extend the concept to reactions of chlorination, but especially of iodization in aromatic series. So, for example, the method allows the tri-iodination of aniline or the iodization of anisole or thiophene.

The aromatic derivative (0.1 mmol; 1 eq), Phyto-Fe (0.105 g (5.3% Iron; 0.1 mmol; 1 eq)), Nal (0.1 mmol; 1 eq) and montmorillonite K10 (0.2 g) are mixed and stirred at 80 ° C. for 24 h. At the end of the reaction, the mixture is cooled to room temperature, washed with dichloromethane and analyzed by GC-MS, then by NMR.

Label Conv% Anisole 65% Thiophene 64%

Table 36

The process can also be extended to other salts, such as KSCN, KNO3, and therefore allow direct thiocyanation or nitration under very mild conditions.

Label Conv% KSCN 61% KNO ₃ 83% (79% yield)

Table 37

Example 17. Bio-sourced chemistry of zinc (Zn)

Phyto-Zn is prepared by adding one gram of water hyacinth root extract to 100 mL of a 10 mg / L solution of Zn. After 2 h of stirring, the powder is filtered, dried and treated at 550 ° C.

Example 17.1: Condensation reaction of a carbanion with a carbonyl compound (Doebner-Knoevenagel type reaction)

The Phyto-Zn recovered by recycling exhibits interesting Lewis acid properties. The formation of C-C bonds by reaction of the Doebner-Knoevenagel type constitutes an interesting example. It is involved in the synthesis of many compounds of interest such as atorvastatin, the active principle of an anti-cholesterol drug from Pfizer known under the name of

Tahor in France or Lipitor in the United States, or imiquimod, the active ingredient in Aldara and Zyclara, immune response-modifying drugs used to treat skin conditions. Conventional reaction conditions involve the use of solvents and a base in a stoichiometric amount.

Synthesis of imiquimod

The use of green solvents or even the absence of solvent and the use of heterogeneous catalysis are two possible means of making this reaction greener. The catalytic activity of zinc chloride, a Lewis acid catalyst, in the absence of solvent has been demonstrated for the Knoevenagel reaction. However, zinc chloride is a very hygroscopic compound, difficult to handle and this is homogeneous catalysis.

Catalyst Malononitrile Methyl cyanoacetate Acetylacetone Acetoacetate ethyl - 0% 0% 0% 0% Phyto-Zn 97% 33% 51% 53% K ₂ ZnCl ₄ 82% 44% <5% 0%

Table 38

These results prove the interest of this recycling technique. It leads to a Phyto-Zn whose activity is at least equal to, or even greater than, K ₂ ZnCl <zinc salt present in Phyto-Zn.

Experimental protocol for the Knoevenagel reaction

In a reactor, the Phyto-Zn (0.06 g; 5mol% of Zn), previously heat-treated for 5 min at 150 ° C, is introduced with benzaldehyde (5 mmol, l equiv.) And malononitrile (5 mmol, l equiv.) at room temperature. Then the reaction mixture is heated at 100 ° C for 1 h. The solution is cooled, then the product formed is extracted with ethyl acetate. The conversion is established by GC / MS with biphenyl as an internal standard. It is 97% Knoevenagel adduct.

Example 18. Bio-sourced chemistry of nickel (Ni)

The Ni-loaded biosorbent is useful in organic synthesis. It is, for example, a good catalyst for a coupling reaction, such as the Suzuki reaction.

Procedure of the Suzuki reaction g of ash derived from functionalized water hyacinths and treated at 550 ° C are diluted in 15 mL of formic acid. The solution is brought to reflux. The solution gradually turns from black to green, reflecting the formation of nickel formate. After 7 hours, the medium is cooled, filtered, the solid is washed with formic acid, then with water. It is redissolved in hot hot water and the medium is evaporated under reduced pressure. It is dried, then engaged in Suzuki reaction.

Ni eco-formate is dissolved in a glycerol / BuOH mixture (1/1 by volume) in the presence of two equivalents of potassium carbonate, 1.2 equivalents of boronic acid and one equivalent of iodobenzene . The mixture is brought to 120 ° C. for 8 hours. 80% of coupling product is then observed by GC MS analysis relative to the internal reference (dodecane).

Example 19. Bio-sourced chemistry of rare earths

The cerium-saturated powder was calcined and upgraded in the Biginelli reaction.

Procedure for preparing Phyto-Ce:

mg of ash (hyacinth root powder modified with citric acid) enriched in cerium are diluted in 6.25 mL of 6N HCl acid; the medium is heated at reflux for 6 h. After returning to room temperature, filtration and concentration under reduced pressure, 42 mg of a hygroscopic yellow powder is obtained (26% cerium).

Procedure of the Biginelli reaction:

The solution of ethyl acetoacetate (0.013 g; 0.1 mol), 4-methoxybenzaldehyde (0.014 g; 0.1 mmol) and urea (0.018 g; 0.3 mol) in ethanol (0.05 mL) is heated under reflux in the presence of Phyto-Ce (0.037 g; 0.025 mol) for 2 h 30 min. Part of the solution is taken, centrifuged and the liquid is passed through the GCMS. The conversion of 93% is observed after 2:30.

'oo reflux, 2h30 o —--- ^ό Λ ⁺ T ² h ₂ n%

Biginelli reaction with a Phyto-Ce o

H

93%

Example 20. Epoxidation with ash from the extraction of Mn using powder from the roots of water hyacinths

Epoxidation of alkenes can also be easily achieved from the ash from Mn extraction using water hyacinth root powder in the presence of a cooxidant such as hydrogen peroxide. The method can be advantageously compared to the methods of the literature. The process is simple since it is a direct recovery of the ashes.

No activation was performed.

Phyto-Mn h ₂ o ₂ ξ R ² Substrate Phyto-Mn: Ashes Phyto-Mn: EcoMn Styrene 100% 91% Limonene 79% (including 93% di-epoxy) 50% (100% monoepoxide) Table 39

The easy production of limonene di-epoxide is very interesting, because it is a molecule that can replace epichlorohydrin, without having the drawbacks of its toxicity.

General operating mode:

NaHCO3 (1.5 g; 18 mmol; 5 eq), Mn enriched ash derived from water hyacinth root powder (0.071 g; 0.02 mmol; 0.005 eq of Mn; Mn in ash = 1 , 79%), the DMF / H ₂ O mixture (1/1) (3.3 mL) and the styrene (0.413 mL; 3.6 mmol; 1 eq) are added in a 25 mL flask at 30 ° C in the air. After 10 minutes of stirring, _{30% H 2} O ₂ (3.3 mL; 36 mmol; 10 eq) is added dropwise over 2 h to the reaction mixture at 30 ° C. in air. Stirring is continued for a further 30 min, then the reaction is cooled to room temperature. The product is extracted with dichloromethane and analyzed in GC MS.

Claims (15)

1. Process for preparing a material of plant origin rich in phenolic acids, comprising at least one metal, said process comprising the following steps: at. a preparation of a material of plant origin from a dead plant chosen from: aquatic plants; materials rich in tannins; materials rich in lignin; and obtaining a material of plant origin, rich in phenolic acids, in which the ratio of the intensity of the vibration band of the C = O bond of the COOH group and the intensity of each of the bands of vibration of the aromatic ring determined in FT-IR is between 0.5 and 4, preferably between 1 and 3.5, for example between 1 and 2.5; b. bringing the material of plant origin obtained at the end of step a) into contact with an effluent comprising from 0.1 to 1000 mg / L of at least one metal, preferably for a period of between 1 hour and 2 hours, at a temperature preferably between 10 and 30 ° C; and vs. obtaining a material of plant origin rich in phenolic acids comprising from 1 to 30% by weight of at least one metal relative to the total weight of the material. 2. A method of pollution control or treatment of an effluent comprising at least one metal, said method comprising the following steps: at. a preparation of a material of plant origin from a dead plant chosen from: aquatic plants; materials rich in tannins; materials rich in lignin; and obtaining a material of plant origin, rich in phenolic acids, in which the ratio of the intensity of the vibration band of the C — O bond of the COOH group and the intensity of each of the bands of vibration of the aromatic ring determined in FT-IR is between 0.5 and 4, preferably between 1 and 3.5, for example between 1 and 2.5; b. bringing the material of plant origin obtained at the end of step a) into contact with an effluent comprising from 0.1 to 1000 mg / L of at least one metal, preferably for a period of between 1 hour and 2 hours, at a temperature preferably between 10 and 30 ° C, and vs. obtaining an effluent comprising less than 100 mg / L by weight of said at least one metal. 3. Method according to claim 1 or 2 wherein the material of plant origin is chosen from: the roots of aquatic plants such as water hyacinth or water lettuce; coffee grounds or tea grounds; wheat straw, pine cones, pine bark, coconut husks; preferably among water hyacinth, water lettuce and pine cones. 4. Method according to any one of the preceding claims, in which the material of plant origin comprises phenolic acid functions and is capable of fixing more than 90%, preferably more than 95%, preferably more than 99% by weight. 'at least one metal included in an effluent, said effluent comprising from 0.1 to 1000 mg / L of at least one metal. 5. Method according to any one of the preceding claims, in which the metallic compound comprises at least one metal chosen from platinoids and in particular Pt, Pd or Rh, rare earths and in particular Ce, Eu, Yb and Sc; or from the group consisting of Zn, Mn, Ni, Cu, Fe, Al, Ca, Mg, As, Sb, Cr, Cd, Ni and Co. 6. Method according to any one of the preceding claims, in which: when the plant material is water hyacinth, the effluent comprises at least one metal chosen from Sc, Ni, Ce, Yb, Co, Ni, Cu, Pd , Pt, Rh, Mn, Fe, Zn, As, Cr or Sb, preferably from Sc, Ni, Ce, Yb, Co, Ni, Cu, Pd, Pt, Mn, Fe, Zn or As; when the plant material is water lettuce, the effluent comprises at least one metal selected from Pd, Pt, Rh or Ni, preferably from Pd, Pt or Ni; when the plant material is coffee grounds, the effluent comprises at least one metal chosen from Pd, Pt, Rh, Mn, Fe, Zn, Ni or Cd, preferably from Pd, Pt, Mn, Fe, Zn, Ni or Cd. 7. Method according to any one of the preceding claims wherein the material of plant origin is characterized by a ratio of the intensity of the absorption band of the C = O bond of the COOH group and of the absorption band. of the aromatic ring determined in FT-IR less than 1, preferably between 0 and 1. 8. The method of claim 7 comprising a step of functionalizing the material of plant origin obtained at the end of step a), said step being prior to step b), and obtaining an original material. plant in which the ratio of the intensity of the absorption band of the C = O bond of the COOH group and of the absorption band of the aromatic ring determined in FT-IR is greater than 1, preferably between 1 and 2.5, preferably between 1 and 3. 9. The method of claim 8 wherein the functionalization step is carried out via: a carboxylation reaction of the material of plant origin obtained at the end of step a) with a carboxylic acid anhydride in an aprotic polar solvent such as ethyl acetate, the anhydride being preferably chosen from mixed, cyclic, aliphatic, functionalized anhydrides generated in situ or prior to the implementation of the carboxylation reaction; or - an autocatalyzed esterification reaction between the material of plant origin obtained at the end of step a) and a polyacid, this reaction taking place in a solvent preferably chosen from ethanol or ethyl acetate ; or an esterification reaction followed by hydrolysis and transfunctionalization. 10. Material of plant origin, rich in phenolic acids, comprising at least one metal, said material being capable of being obtained according to the process of claim 8 or 9, optionally comprising functionalized phenolic acid functions. 11. Material of plant origin, rich in phenolic acids, comprising at least one metal, characterized in that the material is dehydrated, optionally crushed, and said plant origin being chosen from: - aquatic plants, preferably the roots of aquatic plants such as water hyacinth or water lettuce; - materials rich in tannins such as coffee grounds or tea grounds; - materials rich in lignin such as wheat straw, pine cones, pine bark, coconut husks, said material exhibiting a ratio of the intensity of the absorption band of the C = O bond of the group COOH and the absorption band of the aromatic ring determined in FT-IR is greater than 1 and optionally comprising functionalized phenolic acid functions. 12. Material according to claim 10 or 11, wherein the degree of functionalization of the material of plant origin is between 0.0007 and 0.0014 moRaon / g of material in the case of water hyacinth and between 0, 0006 and 0.0018 moRaon / g of material in the case of coffee grounds. 13. Process for carrying out an organic synthesis reaction comprising the following steps: at. a heat treatment of a material according to any one of claims 10 to 12 or obtainable according to a process according to any one of claims 1 to 9, preferably at a temperature between 500 and 800 ° C and preferably for a period of between 2 and 8 hours, and obtaining a calcined material; b. the implementation of an organic synthesis reaction involving the calcined material as a catalyst. 14. The method of the preceding claim, wherein step a) comprises an acid treatment of the calcined material. 15. The method of claim 11 wherein the organic synthesis reaction is chosen from: coupling reactions, preferably chosen from; the coupling reactions between heterocyclic or non-heterocyclic brominated derivatives with boronic acids such as the Suzuki reaction; o the Heck reaction; o Sonogashira's reaction; o polymer construction reactions such as polycondensations, reductions, reduction reactions, in particular chosen from: o the reduction reaction of an enone; 5 o the reduction reaction of a carbonyl derivative; - the isomerization reaction of an exocyclic double bond; oxidation reactions, preferably selected from oxidation of alcohols, oxidative halogenation reactions; - electrophilic substitution reactions, such as nitration reactions or Thiocyanation; - condensation reactions, preferably condensation reactions of a carbanion on a carbonyl compound (Doebnei-Knoevenagel type reaction), multi-component reactions such as the Biginelli reaction; and - oxidation reactions of alkenes such as epoxidation and cleavage Oxidizing.