RU2471549C2 - Sorbent - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to sorbents based on natural clay material. Sorbent contains increased amount of montmorillonite making at least 71-82 wt %. Sorbent features specific surface of 73.57 - 118 m²/g, total volume of pores makes 0.2 -0.28 cm³/g, and particle size does not exceed 10 mcm. Sorbent represents the product of concentration of clay material on Belgorod region deposit. Said sorbent can be used as enterosorbent for absorption of toxins and for selective extraction of heavy metal ions from fluids.

EFFECT: multi-purpose sorbent.

Description

The invention relates to sorption materials based on natural substances and can be used in biotechnology, medicine and veterinary medicine as an enterosorbent, as well as for the selective extraction of cations from liquid media.

Known sorbents based on natural substances (soils, rocks, clay materials, silicas) are widely used even without additional processing to absorb both heavy metal ions and organic pollutants.

For example, sorbents for water purification are known, such as:

- diatomite obtained from diatom-based sediments;

- tripoli;

- flask (marl, gray-white clay) is fine-grained, particle size 0.01-0.001 mm, relatively hard, but light porous rock. Density - 1.0-1.3 g / cm ³ ;

- expanded clay;

- montmorillonite is a clay mineral, has a fairly high pore surface per gram of mineral - about 800 square meters, in its class - the best sorbent for water purification from organic compounds. (http://www.a-filter.ru/sorbent_dlya_ochistki_vody)

It is known that the natural mineral montmorillonite is used in the sorption treatment of wastewater containing heavy metals. It contains silicon dioxide - 65.59%, Al ₂ O ₃ - 20.36%, as well as oxides of magnesium, iron, strontium, zirconium, etc. With a sorbent dose of 6 g / l, the removal efficiency from wastewater with an initial concentration of 50 mg / l of chromium (4+) was 60% (http://envp.ru/isslyedovaniye-procyessa-ochistki-stochnih-vod-sodyerjashcih-hrom-s-ispolzovaniyem-montmorillonita)

In addition, it is known from the prior art that as a result of processing bentonite clays, which consist of a clay mineral - sodium montmorillonite, they receive the biologically active additive “Altai absorbent”, which is a fine powder of light pink color, without a pronounced odor, with a slightly astringent tasteful. (http://arnika-inter.com/content/11.html)

The main physicochemical properties of montmorillonite, such as high adsorption ability, high concentration of exchangeable cations, enveloping ability, hydrophilicity, alkalinity, are due to the structure of the crystal lattice of montmorillonite, large specific surface area of its particles and electrokinetic potential. It refers to layered nanosilicates of a structural type 2: 1 with a swelling crystal lattice, where each elementary packet has a thickness equal to 0.94 nm. (Nanotechnology / C.Pool, F. Owens. - M .: Technosphere. - 2005. - 336 p.)

Famous hydroaluminosilicate preparation "Ekos" - a domestic product from mineral raw materials deposits of the Belgorod region. It is intended for the prevention of digestive disorders and the normalization of the intestinal function of animals due to the ability to bind and excrete heavy metals and radioactive isotopes, nitrates, nitrites and pesticide residues, as well as toxins of pathogenic microorganisms, and is a light gray powder with a yellowish, greenish or brown shades, without a specific smell. The size of the particles in the bulk varies from 0.03 to 1000 microns. The total specific radioactivity at the level of 115.4 ± 8.16 Bq / kg, which does not exceed the MPC values. (The use of natural hydroaluminosilicate in animal husbandry and veterinary medicine. Method, recommendations / A.A. Shaposhnikov, N.A. Musienko, A.I. Vezentsev et al. - Belgorod, Belgorod State Agricultural Academy, 2003. - P.4-5 )

The hydroaluminosilicate preparation "Ekos" does not have in its composition chemicals that adversely affect the body of animals and the quality of the products received from them. The additive is non-toxic to animals, does not have cumulative properties. Embryotoxicity, teratogenicity, and irritating effects have not been experimentally established (Certificate of Conformity Mineral Feed Supplement "Ekos" for livestock No.POCC. RU. 11PN34A.00201 dated 03/12/01).

The closest is the sorbent GISH2, described in sources Kormosh E.K., "Modification of montmorillonite-containing clays for complex sorption wastewater treatment", ed. abstract of dissertation for the competition. student Art. Cand. tech. Sciences, Belgorod, 2009 - the entire document and the corresponding dissertation, chapters 3.2 and 3.3., which is an enrichment product of montmorillonite-containing clay with a particle size of not more than 10 microns and a high content of montmorillonite, which has the ability to absorb Fe ³ ions for 60 minutes ⁺ in an amount of 0.250 mg and Cu ^{2+ ions} in an amount of 0.310 mg for 75 minutes

The disadvantages of the prototype is that:

- it is not intended for the sorption of exo- and endotoxins Escherichia coli and Salmonella enteritidis from a liquid nutrient medium,

- does not have a high enough efficiency for the selective extraction of Fe ³⁺ and Cu ²⁺ cations from liquid media,

- the ability of selective extraction of Cr ³⁺ and Cr ⁶⁺ cations from liquid media is not indicated.

The objective of the invention is to expand the range of environmentally friendly sorbents for multipurpose use with increased sorption efficiency based on domestic raw materials.

Technical result:

- the ability of the proposed sorbent to absorb toxins of Escherichia coli and Salmonella enteritidis from a liquid nutrient medium;

- increased absorption capacity of the selective extraction of Fe ³⁺ and Cu ²⁺ ions from liquid media, as well as Cr ³⁺ and Cr ⁶⁺ ions.

As a solution to this problem, a sorbent based on montmorillonite-containing clay is proposed, which, in comparison with the prototype, has the ability to absorb toxins of Escherichia coli and Salmonella enteritidis from a liquid nutrient medium, which allows detoxification of a liquid nutrient medium in which microorganisms were cultured for five minutes without preparing the sorbent .

Moreover, the proposed sorbent has a high absorption capacity with respect to Fe ³⁺ Cu ^{2+ ions} , as well as Cr ³⁺ and Cr ⁶⁺ ions, which allows it to be used for purification of aqueous media.

The proposed sorbent is a powder of light gray color with a yellowish-greenish tint, without a specific odor, with a clay particle size of less than 10 microns, which is obtained by elutriation of montmorillonite-containing clay. Why distilled water is added to the feedstock in a ratio of 1:10 and incubated for 24 hours. After stirring for one minute, the suspension is sedimented for 20 minutes, then a supernatant suspension with a clay particle size of less than 10 microns is taken from the upper 10-centimeter layer. The suspension is defended, after sedimentation the clarified water is decanted, and the precipitate is dried in an oven at 70-105 ° C and crushed in a ball mill to a particle size of not more than 10 microns. The grinding procedure of large agglomerates of dense consistency, formed after drying of the enriched raw materials, does not lead to an increase in the content of montmorillonite, but makes it possible to increase the specific surface, total pore volume and the true density of the sorbent.

The inventive sorbent meets the conditions of "novelty" and "inventive step", because the technical result is achieved by a set of characteristics characterizing it, namely:

- mineralogical characteristics of raw materials - montmorillonite-containing clay,

- mineralogical characteristics of the sorbent - polymineral montmorillonite-containing sorbent with a content of montmorillonite 71-82%, including also illite, quartz and muscovite,

- a characteristic of the chemical composition — a reduced content of silicon oxide, iron and titanium oxides, an increased content of alkali metal oxides, especially Na ₂ O,

- particle size of the sorbent equal to not more than 10 microns,

- ξ potential = -25.7 ± 2 mV,

- the specific surface is from 73.57 to 118 m ² / g, the total pore volume is from 0.2 to 0.28 cm ³ / g and the true density is from 2.2 to 2.24 g / cm ³ .

By the method of x-ray phase analysis it was found that both the prototype and the proposed sorbent are polymineral montmorillonite-containing. In addition to montmorillonite, they contain illite, quartz, calcite and muscovite. The content of montmorillonite in the prototype 74.5-95.2 wt.%, And in the proposed sorbent - 71-82 wt.%. The increase in the content of montmorillonite in the prototype and the proposed sorbent is due to the reduced amount of low-temperature trigonal quartz.

An energy dispersive analysis of the chemical composition of the prototype and the proposed sorbent showed (Table 1) that in the proposed sorbent, the proportion of alkali metal oxides, especially sodium oxide, as well as aluminum oxide, was increased, but the proportion of alkaline earth metal oxides, iron and titanium oxides was reduced.

Table 1 The chemical composition of the sorbents, wt.% sorbent SiO ₂ Al ₂ O ₃ FeO Fe ₂ O ₃ TiO ₂ MgO Cao K ₂ O Na ₂ O P ₂ O ₅ p.p.p. ∑ GISH2 61.6-66.4 12.3-12.4 0.2-0.22 3.68-3.95 0.69-0.71 2.25-2.27 4.63 4.72 1.76 1.81 0.64-0.66 0.05 0.06 11.8-12.1 99.6-101.3 Proposed sorbent 63.12 16.72 3.35 0.60 2.20 3.20 1.95 2.06 6.80 100.0

The results obtained by studying the chemical composition of the proposed sample are well comparable with the data of x-ray phase and x-ray diffraction analysis and confirm that the content of the clay component increases during the enrichment process.

The results of determining the specific surface, pore size and true density of the starting and activated samples are presented in table 2.

table 2 Textural characteristics of natural and activated sorbents Sample Specific surface, m ² / g (BET method) Total pore volume, cm ³ / g (BJH method) True density, g / cm ³ Ecos 110-115 0.0947 1.95-1.98 GISH2 110-115 0.0947 2,50 The proposed sorbent 73.57-118 0.20-0.28 2.20-2.24

The data in table 2 indicate that the limiting values of the specific surface area of the proposed sorbent have a larger range compared to the specific surface area of the prototype and analog. The total pore volume is almost doubled. Also, in the enrichment process, an increase in the density of the proposed sorbent and prototype is observed in comparison with the analogue, which can be explained by the fact that they are small multicomponent systems and contain a larger amount of sorption-active montmorillonite in comparison with the analogue, since there is an increase in the packing of finely dispersed particles composing the fraction .

Studies of the electrokinetic potential of these sorbents showed that their surface has a negative charge (Table 3). However, in the proposed sorbent, the electrokinetic potential in absolute value is higher than the analogue, but slightly lower than that of the prototype, which is a consequence of the removal of the fraction of silica sand and other non-clay minerals having a relatively low ξ-potential when enriched. An increase in the absolute value of the charge of clay particles leads to an increase in the absorption capacity of the drug with respect to heavy metal ions.

Table 3 Electrokinetic potential of the studied sorbents Sample ξ potential, mV Ecos -19.5 ± 0.2 GISH2 -32.1 The proposed sorbent -25.7 ± 0.2

Studies of the efficiency of sorption were carried out in laboratory conditions using model solutions with a concentration of Cu ²⁺ , Fe ³⁺ , Cr ³⁺ and Cr ⁶⁺ ions equal to 0.1 mmol / L. The phase ratio (liquid: solid) was 100 ml: 0.05; 0.1; 0.25; 0.5; 1.0; 1.5; 2; 5 g with a sorption duration of one hour. At the end of the sorption, the suspension was filtered and the residual concentration of heavy metal ions was determined in the filtrate by the photocolorimetric method [Workshop on environmental chemistry / M.A. Trubitsin. - Belgorod: Publishing House of BelSU, 2002. - 45 p.]

The results of experimental studies on the efficiency of sorption of iron, copper and chromium cations (III and VI) by various forms of sorbents are shown in table 4.

Table 4 Absorption capacity of sorbents of heavy metal ions sample 1 g The concentration of ions, mg Fe ³⁺ Cu ²⁺ Cr ³⁺ Cr ⁶⁺ Ecos 1,50 2.00 0.12 0.30 GISH2 0.250 0.310 (75 min) - - The proposed sorbent 2.00 5.00 0.23 0.80

From table 4 it is seen that the efficiency of sorption of iron cations by the proposed sorbent in comparison with the analogue is 1.3 times higher, with the prototype - 8 times. In relation to copper ions in comparison with the analogue is 2.5 times higher, with the prototype - 16 times. Regarding chromium ions (III and VI), it exceeds this indicator by 1.9 and 2.7 times, respectively, compared with the analogue, and in the description of the prototype the ability to sorption of these cations is not indicated.

Table 5 Full sorption capacity (PSE), mg.eq / 100 g Sample Fe ³⁺ Cu ²⁺ Ecos 83.5 (250.5 mg / 100 g) 80.5 (161 mg / 100 g) The proposed sorbent 132.0 (396 mg / 100 g) 112.5 (225 mg / 100 g)

When comparing the PSE value, an increase in the absorption capacity of the proposed sorbent was found to be 1.4–1.6 times higher than the analogue, which correlates well with the quantitative content of montmorillonite in the sample. For the prototype, the values of the full sorption capacity are not indicated.

Sorption equilibrium for the prototype is reached by the 60th minute of the experiment, while when using the proposed sorbent, equilibrium occurs already by the 30th minute of exposure. This fact can be explained by an increase in the dispersion of clay raw materials due to an increase in the content of the clay mineral fraction in the sample during enrichment. The cleaning efficiency of the model solution when using a sample of the proposed sorbent is 13-15% higher than when using the prototype.

To confirm the data on the ability to bind the toxins of the enteropathogenic bacteria with the proposed sorbent, we performed a bioassay on white rats weighing 160-180 grams, of which 8 groups of 3 rats were formed.

The rats of the control groups were injected intraperitoneally with a sterile liquid nutrient medium - broth from sprat pancreatic hydrolyzate for the cultivation of microorganisms in a volume of 3 ml. Moreover, the animals of the first control group - broth from pancreatic sprat hydrolyzate for the cultivation of microorganisms in its pure form. The animals of the second control group were injected with a sterile liquid nutrient medium - broth from sprat pancreatic hydrolyzate - taken from the supernatant after 5 minutes of treatment with a sterile proposed sorbent at a dose of 150 mg / ml.

Rats of the first three experimental groups were injected intraperitoneally with toxin-containing 8-day-old liquid killed cultures of Escherichia coli, Salmonella salmonella enteritidis and their mixtures in equal amounts, respectively. and after a 5-minute treatment with the sterile proposed sorbent

Rats of the following three experimental groups were injected intraperitoneally with toxin-containing 8-day-old liquid killed cultures of Escherichia coli Escherichia coli, Salmonella salmonella enteritidis and their mixtures in equal amounts, respectively, after they were subjected to 5-minute treatment with the sterile proposed sorbent.

Laboratory animals were monitored for 7 days.

The results of an experiment on the study of the binding of the proposed sorbent to exo- and endotoxins of enteropathogenic microorganisms are presented in table.6.

Table 6 The results of an experiment on the binding of the proposed sorbent of exo- and endotoxins of enteropathogenic microorganisms Group Composition of injection suspension Dose injection ml Clinical signs The results of observations over 7 days 1 control Liquid culture medium 3 Depression, lethargy, lack of appetite for 6-8 hours Recovery of physiological functions has begun 2 control Liquid culture medium treated with the proposed sorbent 150 mg / ml 3 after 6-8 hours. On the 7th day, deviations from the physiological norm were not noted 1 experienced Liquid culture of killed E. coli 3 Severe depression, lethargy, apathy, lack of appetite for 20-24 hours The restoration of physiological functions began a day later. On the 7th day, deviations from the physiological norm were not noted 2 experienced Liquid culture of slaughtered salmonella 3 Severe depression, apathy, lethargy, lack of appetite One rat fell after 1.5 hours; in the other two, a gradual restoration of physiological functions began in a day 3 experienced A mixture of killed liquid cultures of kish. sticks and salmonella 3 (1.5 + 1.5) Severe depression, lethargy, apathy, lack of appetite for 20-24 hours The restoration of physiological functions began a day later. On the 7th day, deviations from the physiological norm were not noted 4 experienced Killed liquid quiche culture. sticks treated with the proposed sorbent 100 mg / ml mg / ml 3 Oppression and lack of appetite for 8-9 hours Recovery of physiological functions began after 8-9 hours. On the 7th day, deviations from the physiological norm were not noted 5 experienced Killed liquid salmonella culture treated with the proposed sorbent 150 mg / ml 3 Oppression and lack of appetite for 9-10 hours Recovery of physiological functions began after 9-10 hours. On the 7th day, deviations from the physiological norm were not noted 6 experienced A mixture of killed liquid cultures of kish. sticks and salmonella treated with the proposed sorbent 150 mg / ml 3 Oppression and lack of appetite for 8-9 hours Recovery of physiological functions began after 8-9 hours. On the 7th day, deviations from the physiological norm were not noted

From table 6 it is seen that the introduction of rats in control groups of sterile liquid nutrient medium and sterile liquid nutrient medium treated with the proposed sorbent, causes slight inhibition, lethargy and lack of appetite for 6-8 hours, followed by restoration of physiological functions. Thus, we can conclude that the proposed sorbent does not have an irritating and toxic effect on the biological organism.

In the first and third experimental groups, after the intraperitoneal injection of killed cultures containing exo - and endotoxins, rats did not die. However, severe oppression, lethargy, lack of appetite were noted for 20-24 hours, animals did not respond to external stimuli. In the second experimental group, 1 rat fell 1.5 hours after the introduction of killed salmonella broth cultures containing exo - and endotoxins, and the remaining 2 were inhibited, apathetic, and only a day later began to take food in small quantities, and complete recovery was noted only by the end of the second day. Animals of the fourth and sixth experimental groups after intraperitoneal injections of killed cultures of microorganisms treated for five minutes with the proposed sorbent were inhibited for 8-9 hours, and in the fifth for 9-10 hours. And immediately after the expiration of this time, the restoration of physiological functions was noted.

For experiments on rats, the amounts of sorbent indicated in the table were selected on the basis of preliminary experiments, which showed that 100 mg / ml of the proposed sorbent is sufficient for deproteinization of a killed 8-day-old E. coli culture, and for the most complete removal of proteins from a similar culture S .enteritidis needs 150 mg / ml of the proposed sorbent.

Based on the studies, it can be stated that the proposed in vitro sorbent binds endo- and exotoxins of Escherichia coli and Salmonella, because clinical signs in the form of depression, lethargy and lack of appetite in rats that were injected treated with the proposed sorbent injection, passed almost the same time as in rats from the control groups.

Thus, the task is solved. An environmentally friendly multi-use sorbent based on domestic raw materials with increased efficiency of sorption of both exo- and endotoxins of enteropathogenic microorganisms and iron, copper and chromium ions (III and VI) can be used in the treatment of animals with gastroenteritis by reducing the absorption of bacterial toxins and breakdown products of intestinal contents, as well as for the purification of aqueous media.

Claims (1)

Multipurpose sorbent with the ability to absorb exo- and endotoxins of Escherichia coli and Salmonella enteritidis, as well as heavy metal cations Fe ³⁺ and Cu ²⁺ from liquid media, which is an enrichment product of montmorillonite-containing clay, which also contains illite, quartz, calcite and muscovite, in in the form of particles with a size of not more than 10 μm, characterized in that it is capable of absorbing Cr ³⁺ and Cr ⁶⁺ cations from liquid media, while the content of montmorillonite is 71-82 wt.%, the specific surface is from 73.57 to 118 m ² / g, total pore volume from 0.2 to 0.28 cm ³ / g, and ξ - potential is equal to - 25.7 ± 0.2 mV.