RU2524956C1 - Silicon-humus soil ameliorant - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to environmental conservation technologies, cutting-edge agricultural technologies and chemistry of organosilicon compounds and can be used to restore the structure of disturbed soils by stabilising water-stable aggregate. In particular, the present invention employs water-soluble humic silanol derivatives that are modified in a special way to endow them with the capacity to be irreversibly sorbed on surfaces of mineral particles and other hydroxyl-containing carriers. Humic derivatives are added to the degraded soil in form of aqueous solutions.

EFFECT: method for use in agricultural technologies includes using humic derivatives as structure-forming agents (soil ameliorants) by via attachment thereof to the surface of soil aggregates in order to endow the latter with water-stable properties.

8 cl, 11 dwg, 8 tbl

Description

FIELD OF THE INVENTION

The invention relates to the field of environmental technologies, advanced agricultural technologies and chemistry of organosilicon compounds and can be used to restore the structure of disturbed soils by stabilizing water-resistant aggregates. In particular, the invention uses water-soluble humic silanol derivatives that have been specially modified to give them the ability to be irreversibly sorbed on the surfaces of mineral particles and other hydroxyl-containing carriers. The method of application in agricultural technologies consists in the use of humic derivatives as structurants (soil reclamants) by fixing them on the surfaces of soil aggregates in order to give the latter water-resistant properties. Humic derivatives are introduced into degraded soils in the form of aqueous solutions.

State of the art

Soil degradation poses a significant threat to the environment. This is due to the accelerated decomposition of organic carbon in the conditions of structureless soils and, as a result, with an increase in the emission of carbon dioxide from soils. The main factor preventing the decomposition of organic matter in soils is the formation of water-resistant aggregates [Mayer L.M., Schick L.L., Hardy K.R., Wagai R., McCarthy J. 2004 Organic matter in small mesopores in sediments and soils. Geochimica et Cosmochimica Acta, 68, 3863-3872]. Therefore, with an increase in the anthropogenic load from native to tilled soils, both the number of water-resistant aggregates and the organic matter content sharply decrease [Six J., Elliott E.T., Paustian K., Doran J.W. 1998. Aggregation and soil organic matter accumulation in cultivated and native grassland soils. Soil Sci. Soc. Am. J. 62, 1367-1377]. Until recently, it was believed that the leading mechanism for the formation of water-resistant aggregates is the bonding of mineral particles by bridge bonds formed due to the interaction of carboxyl groups of the humic component of soil organic matter and metal ions in the mineral complex [Varadachari, S., A.N. Mondal, DCNayak , and K. Gosh. 1994. Clay-humus complexation: Effect of pH and the nature of bonding. Soil Biol. Biochem. 26, 1145-1149]. At the same time, recent studies show the leading role of hydrophobic interactions in this process, due to the unique properties of humic films fixed on the surface of finely divided mineral particles, to glue these particles into aggregates [Shein E.V., Milanovsky E.Yu. 2003, The role and importance of organic matter in the formation and stability of soil aggregates. Soil Science, Nos. 1, 53-61, Goebel, M.O., S.K. Woche, J. Bachmann, A. Lamparter, W.R. Fischer. 2007. Significance of wettability-induced changes in microscopic water distribution for soil organic matter decomposition. Soil Sci. Soc. Am. J. 71: 1593-1599].

An analogue of the proposed development can be considered a method of restoring the water resistance of soil aggregates described [Piccolo, A., and J.S.C. Mbagwu. 1999. Role of hydrophobic components of soil organic matter in soil aggregate stability. Soil Sci. Soc. Am. J. 63: 1801-1810]. The authors studied the effect of hydrophilic and hydrophobic components of soil organic matter on the formation of water-resistant aggregates and found the maximum increase in their amount in the soil, in which humic acids of coal and highly hydrophobic stearic acid were successively added. Another analogue, which is selected as a prototype, is the method of soil conditioning described in US patent (US 5248327), which consists in introducing a product based on coal into degraded soil. This product is oxyhumic acids or their salts, a special property of which is the ability to form gels when swelling in water. Thus, both of these methods involve the addition of salts of coal humic acids, the effect of which is enhanced either by combining with a hydrophobic polymer (stearic acid) or by modifying coal, from which humic acids are then isolated. The disadvantage of the proposed methods is that both products are water-soluble humates that are quickly washed out of the soil layer. This determines the fragility of the effect of restoring the water resistance of soil aggregates.

Silica-humic derivatives, which are proposed for use as ameliorants of soils with a disturbed structure, are deprived of these drawbacks. Their advantage is that they have a high adhesive ability with respect to hydroxyl-containing surfaces, contributing to the formation of hydrophobic humic films. Surface hydrophobization plays an important role in the formation of water-resistant aggregates in soil (Piccolo, A., and JSC Mbagwu. 1999. Role of hydrophobic components of soil organic matter in soil aggregate stability. Soil Sci. Soc. Am. J. 63: 1801-1810 ) This allows us to consider the proposed humic derivatives as reagents of a new generation, which have great potential for practical application in both environmental and advanced agricultural technologies. An important advantage of humic derivatives is a long life in soil conditions, safety from the standpoint of secondary pollution and biocompatibility.

Disclosure of invention

The claimed solution relates to a class of new compounds, namely, humic silanol derivatives, which are modified so that they acquire the ability to firmly adsorb on hydroxyl-containing solid surfaces, causing their partial hydrophobization, and which can be used both in dissolved and in immobilized form.

Accordingly, the subject of the invention includes both the new humic silanol derivatives themselves and methods for treating the surfaces of natural minerals with them, aimed at increasing the water resistance of soil aggregates and improving the structure of degraded soils.

Another subject of this invention is humic silanol derivatives to improve soil structure, which are capable of being strongly sorbed by solid hydroxyl-containing surfaces due to the formation of siloxane bonds, which contributes to the formation of humic coatings and, accordingly, provides an increase in the hydrophobicity of the treated surfaces.

Another subject of this invention is a method for the synthesis of humic silanol derivatives, which allows to obtain such humic derivatives, using which it is possible to improve soil quality.

It unexpectedly turned out that the treatment of humic substances with amino organosilanes in an aqueous medium, followed by distillation of the water and heating of the product, leads to the production of silanol humic derivatives, which are soluble in alkaline aqueous media, but easily pass from the solution to the solid phase upon contact with solid carriers containing hydroxyl groups on surface. In this case, the resulting humic silanol derivatives are able to bond strongly to the hydroxylated surface of the solid substrate due to the formation of Si-O-Si siloxane bonds (in the case of silicon-containing substrates such as silicas, silicates, aluminosilicates, etc.) and Si-OM (where M is a metal ) bonds in the case of metal oxides and hydroxides. This allows the use of silanol humic derivatives as soluble reagents to increase the water resistance of soil aggregates and improve soil structure. In this case, when introduced into the soil, humic silanol derivatives are fixed in the soil layer, hydrophobizing the surface of mineral particles due to the formation of organic films, and contribute to their bonding to water-resistant aggregates.

Another advantage of using humic derivatives as soil ameliorants is the availability of inexpensive and abundant humic raw materials necessary for the production of humic derivatives mentioned in this invention. Such raw materials include various types of coal, peat, sapropel, oil shale called caustobiolites, as well as composts, vermicomposts and other similar materials. The starting humic substances can be used both in protonated form (humic and fulvic acids), and in the form of salts (humates and fulvates) and as pre-modified derivatives enriched with various functional groups. Microbial decomposition products of lignin, wood, coal, and other microbial synthesis products, as well as lignosulfonates and other oxidized materials, can also be used. Taking into account that humic substances do not have a constant stoichiometric composition and regular structure, they are characterized by the content of basic constitutional elements. By such, we mean that unmodified HSs are composed of compounds with the following element contents: from about 20 to about 70.% (mass.) C, from about 2 to about 10% (mass.) N, from about 15 to about 55% (mass.) O, from about 0 to about 10% (mass.) N, and may contain from about 0 to about 10% (mass.) S and from about 0 to about 50% (mass.) ash. In addition, these compounds may contain from about 1 to about 15 mmol / g of carboxyl groups, from about 1 to about 10 mmol / g of hydroxyl groups, and from about 0.5 to about 10 mmol / g of carbonyl groups. For the preparation of humic derivatives of the present invention, amino organosilanes with various substituents in the aliphatic chain and alkoxysilyl substituents at the silicon atom, which can react with carboxylic groups of humic substances, can be used. By aminoorganosilanes we mean alkoxysilanes which have one amino group separated from the Si atom by at least one, but preferably three, methylene groups and at least one, but preferably three, alkoxy substituents.

Until now, the possibility of obtaining soluble humic derivatives capable of spontaneously adsorbing on mineral surfaces is described only in patent RU 2429068. The principal difference of this invention is that humic silanol derivatives are obtained in an aqueous medium, while the synthesis of alkoxysilyl derivatives described above is carried out in an environment an anhydrous organic solvent (e.g., DMF). Another fundamental difference is that the dissolution of alkoxysilyl humic derivatives in an aqueous medium is accompanied by the hydrolysis of alkoxysilyl groups and the release of aliphatic alcohols polluting the environment. The silanol derivatives of the present invention, which are soluble in water without the formation of by-products, are free from this drawback. In addition, alkoxysilyl derivatives usually contain residual amounts of solvent (for example, DMSO), which is also associated with the risk of secondary contamination. The synthesis of silanol derivatives of the present invention is carried out in water, which eliminates this problem.

It was unexpectedly found that the introduction of silanol groups in the composition of humic macromolecules does not lead to the formation of insoluble humic polymers crosslinked by siloxane bonds. On the contrary, humic silanol derivatives dissolve well in aqueous media in the region of alkaline pH, but can be easily removed from solution by contact with solid substrates containing hydroxyl groups on the surface. The process of immobilization of humic derivatives on inorganic surfaces occurs due to the reaction of silanol groups with hydroxyls with the formation of covalent Si-O-Si or Si-O-M bonds (where M is a metal). Thus, the silanol groups act as linkers between the humic film and the solid substrate. The advantage of the formation of a humic film on mineral surfaces is its hydrophobic nature, which ensures the bonding of modified particles into water-resistant aggregates.

The scope of the invention is to restore the water resistance of soil aggregates and improve the structure of soils by introducing solutions of humic silanol derivatives, followed by plowing of the treated soil layer. The introduction of humic derivatives is carried out by drip irrigation or as part of a mixture with liquid and complex fertilizers. Sorption of humic derivatives on the mineral components of degraded soils ensures their bonding to water-resistant aggregates and, as a result, allows to restore the structure of soils.

To obtain spontaneously adsorbed humic derivatives according to the method proposed in the present invention, a humic preparation, which can be used as humic acids or fulvic acids in protonated form or in the form of alkali metal salts, as well as dissolved organic matter and humic like lignin oxidation products, is dissolved in aminoorganosilane (e.g. 3-aminopropyltrimethoxysilane (APTS), or 3-aminopropyltriethoxysilane (APTS), is added dropwise to the aqueous medium and to the resulting solution, or 1-aminohexamethylene 6-aminomethylenetriethoxysilane (AGTS)). Next, adjust the pH of the solution to 3-7 with a mineral acid (e.g., HCl). Then the water is evaporated and the reaction product is placed in an oven at 30-150 ° C for 6-8 hours. The resulting product can be defined as silanol humic derivatives. They differ from the initial HS both in their physicochemical properties and in their elemental and functional composition. Silanol humic derivatives contain from 2 to 10 mmol / g silanol groups and have elemental composition,% (mass.): Si 2-8; C 30-55, H 3-5 and N 2-5. Some formulations of humic derivatives may contain sulfur in the range from about 0.5 to about 5% (mass.). They can be dissolved in water and immobilized irreversibly on mineral and other hydroxyl-containing solid substrates.

Brief Description of the Drawings

Figure 1 - IR spectra of hepatitis B and a modified preparation of hepatitis B-APTS.

Figure 2 - ¹³ C NMR spectra of the preparations of HB of Leonarditis and the silanol derivative of HB-APTS.

Figure 3 - IR spectra of the HS of coal and silanol derivative of the HS-AGTS.

Figure 4 - ¹³ C NMR spectra of drugs GV and GV-AGTS.

Figure 5 - IR spectra of HB peat (PHA-Na) and a modified drug RNA-APTS.

6 is a micrograph of a drop of water on various glasses; (A) - APTS-modified glass; (B) - source glass; (C) - glass modified with the preparation GV-APTS.

7 - images of the original glass (left) and modified HV-APTS (right) obtained using atomic force microscopy (AFM).

Fig. 8 is an estimate of the water resistance of soil aggregates treated with humic silanol derivatives. On the left are soil aggregates before the experiment, on the right, at the final stage of the experiment.

Fig.9 is a kinetic dependence of the number of soil aggregates disintegrated under the influence of water, provided that they are pretreated with water, the initial potassium humate and the preparation GV-APTS.

Figure 10 - the formation of water-resistant aggregates from soil particles with a size of <0.25 mm under the influence of humic silanol derivatives (GV-APTS).

11 - the effect of HS of coal and their silanol derivatives (HS-APTS) on the content of agronomically valuable aggregates in the soil.

The implementation of the invention

The invention consists in the preparation of water-soluble humic silanol derivatives capable of being irreversibly sorbed on a solid matrix, which as a result acquires partially hydrophobic properties. For this, humic substances are modified with aminoorganosilanes in an aqueous medium. Silanol groups introduced into the structure of humic substances can react with hydroxyl groups on the surface of solid substrates, forming covalent Si – O – Si and Si – O – M bonds.

Any known humic or humic like substances may be used in the invention. It can be various coals, peat, sapropel, compost, etc. These substances or their modifications can be used both in protonated form and in the form of salts. Moreover, in addition to humic substances, other humic-like substances can be used in the invention: composts and biohumus, as well as other materials containing an organic component with carboxyl groups (products of biological decomposition of lignin, wood, coal, etc.). Since humic substances do not have a specific chemical structure, they are characterized by the content of basic elements. Thus, hereby, humic substances are understood to mean compounds containing from 20 to 70 weight% carbon, from 2 to 10 weight% hydrogen, from 15 to 55 weight% oxygen, from 0 to 10 weight% nitrogen and from 0 to 50 weight% ash . Sometimes humic substances contain from 0 to 10 weight% sulfur.

The solid surface for sorption of silanol derivatives of humic substances described in the invention should contain hydroxyl groups. This definition includes: silica gel, sand, quartz, silicates, aluminosilicates, alumina, aluminum, calcite, inorganic oxides (Al ₂ O ₃ , Fe _x O _y , TiO ₂ , Cr ₂ O ₃ , etc.), glass, asbestos granular media (gravel) and other similar materials.

As was noted, the modification of humic substances can be carried out using aminoorganosilanes. The main types of organosilanes that can be used for these purposes are shown in Table 1. Under alkoxysilyl groups are meant groups containing from 1 to 20 carbon atoms. The present invention describes the use of methoxy and ethoxy derivatives because of their higher hydrolysis ability and, as a consequence, their higher reactivity with respect to surfaces containing hydroxyl groups. Aminoorganosilanes containing one, two or three alkoxysilyl groups, or a mixture thereof can be used within the framework of this invention. The following can be used as such organosilanes:

3-aminopropyl dimethylmethoxysilane, 3-aminopropylmethyldimethoxysilane,

3-aminopropyltrimethoxysilane, 3-aminopropyldimethylethoxysilane,

3-aminopropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane,

1-aminohexamethylene 6-aminomethylene trimethoxysilane,

1-aminohexamethylene 6-aminomethylenetriethoxysilane and others.

It is preferable to use trialkoxysilanes, since in this case the modified humic substances contain three reactive alkoxy groups, which leads to a more effective interaction with hydroxyl-containing surfaces. However, this invention does not exclude the use of mono and di-alkoxysilanes for the modification of humic substances.

It unexpectedly turned out that after treatment of humic substances with amino organosilanes in an aqueous medium acidified to pH 3-7, and subsequent heating of the product at 30-150 ° C for 6-8 hours or longer, humic derivatives are obtained that can dissolve in alkaline solutions, which allows them to be used as macromolecular silylating agents. Silanol derivatives of humic substances have not been previously described. Silanol humic derivatives significantly differ from the initial ones in elemental and functional compositions, as well as in their ability to be irreversibly sorbed on mineral OH- and -O-containing surfaces. Differences in the composition and properties of the initial and modified HS were demonstrated using various physicochemical methods, such as elemental analysis, titrimetry, IR and NMR spectroscopy.

Table 1 Organosilanes that can be used to modify humic substances Functionality Title Structure Amino 3-aminopropyltrialkoxysilane (APTS) H ₂ N (CH ₂ ) ₃ SiR _n (OR) _3-n , where n = 0-2, R is a methyl or ethyl radical Amino 1-aminohexamethylene 6-aminomethylene trialkoxysilane (AGTS) H ₂ N (CH ₂ ) ₆ NHCH ₂₃ SiR _n (OR) _3-n , where n = 0-2, R is a methyl or ethyl radical

Silanol humic derivatives are characterized by the following composition and properties. Their elemental composition satisfies the following intervals (%): Si 2-8, C 30-55, H 3-7 and N 2-8. They contain from 0.5 to 5 mmol of silanol groups per 1 g of humic substances, depending on the selected degree of modification of the functional groups of HS. They can be dissolved in an alkaline solution and irreversibly sorbed on OH-containing solid supports.

The preparation of silanol derivatives of humic substances is carried out according to the following procedure:

1. The starting solid HBs are homogenized.

2. Homogenized HS are dissolved in aqueous alkali and a solution of a mineral acid (for example, HCl) is added dropwise to the resulting solution until a pH of 3-7 is established

3. Then, aminoorganosilane is added dropwise with constant stirring until the molar ratio of the functional groups of the reactants (organosilane: HS) is from 0.1: 1 to 2: 1. The reaction is carried out at room temperature for 1 hour.

4. The reaction product is separated from water using a rotary evaporator.

5. The resulting substance is heated in a vacuum oven at a temperature of 30-150 ° C for 6-8 hours or longer.

The authors found that the obtained silanol humic derivatives can be used to obtain films on hydroxyl-containing surfaces. These films are obtained using the following methods:

1. Solid humic derivatives obtained by the method described above are homogenized and mixed with a concentrated alkali solution (from 1 to 50%) in a volume ratio of 1: 1 to 1: 5.

2. The alkaline solution of humic derivatives is diluted with distilled water to a concentration of from 0.01 to 10% and (if necessary) acidified to pH 5-7.

3. The resulting solution is used for the treatment of hydroxyl-containing surfaces.

The obtained silanol humic derivatives can be used to increase the water resistance of soil aggregates and improve the structure of degraded soils. The indicated effect is achieved using the following methods.

1. Solid humic derivatives obtained by the method described above are homogenized and mixed with a concentrated alkali solution (from 1 to 50%) in a volume ratio of 1: 1 to 1: 5.

2. An alkaline solution of humic derivatives is diluted with distilled water to a concentration of 0.1 to 10% and (if necessary) acidified to pH 5-7.

3. The resulting solution is used for application to degraded soils by drip irrigation or irrigation both separately and together with the introduction of complex and liquid fertilizers.

The invention is illustrated by examples (but not limited to).

Examples 1-3 describe the synthesis of silanol humic derivatives. The composition and structure of the derivatives obtained are confirmed by elemental analysis, titrimetry, IR and ¹³ C NMR spectroscopy. The results of elemental and functional compositions are presented in tables 2-7, IR and ¹³ C NMR spectra are given in figure 1-4. Example 4 describes the properties of a surface modified by humic silanol derivatives, in particular its hydrophobization. Examples 5-6 demonstrate an increase in the water resistance of soil aggregates as a result of treatment with silanol derivatives. Example 7 describes an improvement in the structure of soils treated with humic silanol derivatives.

Example 1

This example describes the synthesis of silanol derivatives of humic substances using aminoorganosilane and Leonardite humic substances in the form of potassium humate. The reaction was carried out in a one-necked flask equipped with a stirrer. A portion of 50 g of potassium humate was dissolved in distilled water, and then, with vigorous stirring, 15 ml of 3-aminopropyltriethoxysilane (APTS) were added dropwise. This molar ratio of the reactants is 1: 0.5, since 1 g of the used HS contains 2.7 mmol of carboxyl groups that react with APTS; 1 ml of APTS contains 4.2 mmol of amino groups. Then, 28 ml of a hydrochloric acid solution (5M) was added dropwise to the solution to establish a pH of 4. The reaction was conducted for 10 minutes at room temperature. After completion of the reaction, water was distilled off on a rotary evaporator and the resulting compound was placed in an oven at a temperature of 125 ° C for 6 hours. Then, the resulting compound was homogenized and placed in a desiccator. The mass of the obtained compound was 56.2 g.

The structure of the obtained silanol derivatives was confirmed by elemental analysis and titrimetry (the results are presented in tables 2 and 3), as well as using IR and ¹³ C NMR spectroscopy. The spectra are given in figures 1 and 2.

table 2 The elemental composition of the initial and modified HS calculated on an ashless sample (%) Sample FROM N N Si HS Leonardita 52.6 5.1 2.1 6.3 GV-APTS 55.5 6.1 4.4 8.4

Table 3 The content of carboxyl groups in the initial and modified HS (mol / g) Sample -COOH C _ave ± ΔC HS Leonardita 2.7 ± 0.2 GV-APTS 1.7 ± 0.5 ^* ΔС is the confidence interval, n = 3, P = 0.95.

From the results of elemental analysis, an increase in the content of nitrogen and silicon in the modified preparations follows. From titrimetric data, a decrease in the content of carboxyl groups in modified preparations follows. These changes confirm the high degree of modification of carboxyl groups in the initial HS.

It was found that HB Leonardite modified by APTS can contain from 2 to 10% Si, from 30 to 55% C, from 3 to 5% H and from 2 to 5% N. They can also react with hydroxyl-containing surfaces, forming covalent bonds Si-O-Si or Si-OM, where M is a metal surface containing hydroxyl groups.

Figure 1 presents the IR spectrum of the preparation of the initial HB. The presence of the vibrational band of the C = C bonds of the aromatic ring (about 1610 cm ⁻¹ ) in the IR spectrum of the unmodified preparation of HB Leonardite indicates the presence of an aromatic framework. The band in the region of about 1710 cm ^-1 refers to the C = O bond vibrations and confirms the presence of carboxyl and carbonyl groups in the preparation, the band in the region of 1250 cm ^-1 refers to the stretching vibrations of CO phenolic and carboxyl groups, the bands in the range of 1050-1150 cm ^{- 1} correspond to bond vibrations of CO alcohol groups. The presence of these bands indicates the presence of various oxygen-containing functional groups in HS preparations.

The spectra of modified preparations contain both bands characteristic of hepatitis B and a modifier. Figure 1 shows that in the preparation of GV-APTS, in addition to the superposition of GV and APTS (two strong bands at 1100 and 1050 cm ^-1 , characteristic of Si-O vibrations), there is a band at 1265 cm ^-1 , which is characteristic of vibrations in the amide plane bond (amide 3 band), which indicates the formation of an amide bond. This is also confirmed by the shift of a wide band at 1600 cm ^–1 to the short-wavelength region, which indicates an increase in the contribution of vibrations of carbonyl atoms in the amides to this peak.

According to NMR spectroscopy on ¹³ C nuclei, the following main types of carbon, depending on its chemical environment, were identified as part of the initial HS: 220-185 ppm - carbonyl carbon (C _{C = O} ); 185-165 ppm - carboxyl carbon (C _COOH ); 165-140 ppm - aromatic carbon bound to oxygen (C _ArO ); 140-100 ppm - unsubstituted or C-substituted aromatic carbon (C _Ar ); 100-50 ppm - aliphatic carbon bound to oxygen (C _AlkO ); 50-3 ppm - carbon alkyl groups (C _Alk ). The following assignment of peaks 11.1 ppm, 26.8 ppm can be made in the spectrum of the drug GV-APTS and 43.8 ppm - carbons corresponding to the propyl chain in the structure of the modifier. It should be noted that a peak at 167-168 ppm, characteristic of the carbon of the amide bond, appears on the spectra of modified HSs, and the peak intensity decreases at 175 ppm, characteristic of carboxyl groups. These changes in the spectra indicate the passage of the amidation reaction.

Example 2

This example demonstrates the possibility of using 1-aminohexamethylene 6-aminomethylene trimethoxysilane (AGTS) as the aminoorganosilane. The reaction was carried out in a one-necked flask equipped with a stirrer. A portion of 5 g of potassium humate, isolated from coal, was dissolved in distilled water, and then, with vigorous stirring, 4.2 ml of 1-aminohexamethylene 6-aminomethylene triethoxysilane (AGTS) were added dropwise. This molar ratio of the reactants is 1: 1, since 1 g of the used HS contains 2.7 mmol of carboxyl groups that react with AGTS; 1 ml of AGTS contains 3.3 mmol of amino groups. Next, 5 ml of hydrochloric acid solution (5 M) was added dropwise to the solution until pH 4 was established. After adding acid, 100 μl of PMS-300 was added to the flask as an antifoam. The reaction was carried out for 10 minutes at room temperature. After completion of the reaction, water was distilled off on a rotary evaporator and the resulting compound was placed in an oven at a temperature of 125 ° C for 6 hours. Then, the resulting compound was homogenized and placed in a desiccator. The mass of the obtained compound was 7.4 g. The structure of the obtained substance was proved by elemental analysis and titration (Tables 4 and 5), as well as by IR spectroscopy and ¹³ C NMR spectroscopy (Figs. 3 and 4).

Table 4 Elemental composition (per ashless sample) (% wt.) Of the initial preparation of HS and AGTS-derivatives of HS Sample FROM N N Si GV Leonardite potassium salt 52.6 5.1 2.1 6.3 GV-AGTS 53.5 7.1 7.6 8.8

Table 5 The content of acid groups in the initial and AGTS derivatives of HB (mmol / g) Sample -COOH C _ave ± ΔC HS Leonardita 2.7 ± 0.2 GV-AGTS 2.5 ± 0.5 ^* ΔC - confidence interval (mmol / g), n = 3, P = 0.95

From the data of elemental analysis, an increase in the content of silicon and nitrogen in the modified product follows. Titrimetric data show a decrease in the content of carboxyl groups, which is confirmed by the fact that they reacted with AGTS.

Figure 3 shows the IR spectra of the initial HS and silanol derivatives of HS obtained when used as a modifier of AGTS. In the spectrum of HV-AGTS, in addition to the bands obtained by superposition, one can note the presence of a band at 1690 cm ^-1 , which is characteristic of C = O in the amide bond, as well as the band at 1268 cm ^-1 , characteristic of amides.

For the ¹³ C NMR spectrum of the drug GV-AGTS-100 (Fig. 4), peaks were 26.1 ppm, 26.8 ppm, 31.4 ppm, 34.5 ppm, 40.5 ppm, 50.4 m .d. belong to the carbon atoms of the aliphatic chain in the modifier. In addition, a peak at 167-168 ppm, characteristic of the carbon of the amide bond, appears on the spectra of modified HSs, and the peak intensity decreases at 175 ppm, characteristic of carboxyl groups. Thus, it was shown by NMR and IR spectroscopy that the amide bond is formed as a result of the addition of AGTS aminorganosilane to the humic framework.

Example 3

This example demonstrates the possibility of applying for the modification of humic substances isolated from peat raw materials. For the reaction, unfractionated humic substances isolated from lowland peat were used. The reaction was carried out in a one-necked flask equipped with a stirrer. A portion of 5 g of sodium humate was dissolved in 100 ml of distilled water, and then, with vigorous stirring, 3.5 ml of 3-aminopropyltriethoxysilane (APTS) were added dropwise. This molar ratio of reagents is 1: 1, since 1 g of used HS contains 3.0 mmol of carboxyl groups that react with APTS; 1 ml of APTS contains 4.2 mmol of amino groups. The reaction was carried out for 10 minutes at room temperature. Next, 5 ml of hydrochloric acid solution (5 M) was added dropwise to the solution until pH 4 was established. After adding acid, 100 μl of PMS-300 was added to the flask as an antifoam. After completion of the reaction, water and hydrolyzed alcohol were distilled off on a rotary evaporator, and the resulting compound was placed in an oven (120-150 ° C, 760 mm Hg). Then, the resulting compound was homogenized and placed in a desiccator. The mass of the obtained compound was 6.3 g. The structure of the obtained substance was proved by elemental analysis and titration (Tables 6 and 7), as well as by IR spectroscopy (Fig. 5).

Table 6 Elemental composition based on ashless sample (% wt.) Of the initial preparations of PHA-Na and their silanol derivatives Sample FROM N N Si PHA-Na 49.5 4.9 3,7 0.6 RNA-APTS 51.1 6.2 7.0 5.5

Table 7 The content of acid groups in silanol derivatives of PHA-Na (mmol / g) Sample -COOH C _ave ± ΔC PHA-Na 2.9 ± 0.2 RNA-APTS 1.7 ± 0.5 ^* ΔC - confidence interval (mmol / g), n = 3, P = 0.95

From the results of elemental analysis, an increase in the content of nitrogen and silicon in the modified preparations follows. From titrimetric data, a decrease in the content of carboxyl groups in modified preparations follows. These changes confirm the high degree of modification of carboxyl groups in the initial PHA-Na.

It was found that HS peat modified with APTS can contain from 2 to 8% Si, from 30 to 55% C, from 3 to 5% H and from 2 to 5% N. They can also react with hydroxyl-containing surfaces, forming covalent bonds Si-O-Si or Si-OM, where M is a metal surface containing hydroxyl groups.

Figure 5 presents the IR spectrum of the preparation of the initial HS peat, modifier and modified compounds. In the initial HS, the presence of the vibrational band of the bonds of the OS of the aromatic ring (about 1610 cm ^-1 ) in the IR spectrum of the unmodified preparation of the HS of peat indicates the presence of an aromatic framework. The band in the region of about 1710 cm ^-1 refers to the C = O bond vibrations and confirms the presence of carboxyl and carbonyl groups in the preparation, the band in the region of 1250 cm ^-1 refers to the stretching vibrations of CO phenolic and carboxyl groups, the bands in the range of 1050-1150 cm ^{- 1} correspond to bond vibrations of CO alcohol groups. The presence of these bands indicates the presence of various oxygen-containing functional groups in HS preparations.

The spectra of modified preparations contain both bands characteristic of HA and the modifier. Figure 5 shows that in the preparation of GV-APTS, in addition to the superposition of GV and APTS (two strong bands at 1100 and 1050 cm ^-1 , characteristic of Si-O vibrations), there is a band at 1265 cm ^-1 , which is characteristic of vibrations in the amide plane bond (amide 3 band), which indirectly indicates the formation of an amide bond. You can also notice a shift of the wide band at 1600 cm ^-1 to the shorter wavelength region, which indicates an increase in the contribution of vibrations of carbonyl atoms in the composition of amides to this peak.

Example 4

An example describes a method for modifying a solid hydroxyl-containing surface - glass - using humic silanol derivatives and demonstrates its hydrophobization as a result of this treatment. To study the hydrophobicity of coatings formed by silanol derivatives of HV, glass plates were modified. This made it possible to directly determine their hydrophobicity by the value of the contact angle of a water drop on the treated surface.

For the experiment, slides were used, as well as Borafloat glasses for atomic force spectroscopy, cut into equal parts measuring 1 cm by 2 cm. For the application of silanol derivatives of humic substances, the glass surface was first activated. For this, the plates were placed in a muffle furnace in the heating mode to 260 ° C for 1 hour and aging at 260 ° C for 22 hours. Then the plates were cooled to room temperature and placed in an alkaline ethanol solution (10% NaOH and 40% ethanol) for 2 hours at room temperature. Next, the glasses were thoroughly washed first with distilled water, then with ethanol and dried in air. Then, a solution of silanol derivatives of humic substances with a concentration of 1 g / L was prepared. For this, a 50 mg sample of the preparation was wetted with 0.5 M NaOH and placed in an ultrasonic bath for 30 min at 30 ° C. The solution was adjusted to 50 ml with phosphate buffer (pH 6.0, 0.03 M) and centrifuged at 10,000 rps for 10 minutes to separate the insoluble residue. Then 40 ml were taken, the pH of the solution was adjusted to 6.0 with diluted HCl and diluted with phosphate buffer to a concentration of 1 g / l, after which the glass plates were immersed in the resulting solution for 24 hours. Then the plates were thoroughly washed with distilled water and dried in air.

The hydrophobicity of the surface of the obtained plates was estimated by measuring the contact angle of water wetting on the surface. For this glass was placed on the substrate of the device. Then, a drop from a syringe was applied to the glass and micrographs were taken (examples are shown in Fig. 6), then the contact angle of the glass plates was determined from the photos.

Table 8 shows the data obtained by measuring the wetting angle of water on the original glass plates and plates modified with various silanol derivatives of HS.

Table 8 The values of the contact angle on the original and modified glasses A drug Wetting angle, deg Original glass 41 GV-APTS 58 GV-AGTS 58 RNA-APTS 48

From the presented data it is seen that the hydrophobicity of glasses increases when they are treated with silanol derivatives of HS as a result of immobilization of an organic humic film. In this case, the peat film is less hydrophobic than coal. This can be explained by the fact that the composition of peat HS contains a hydrophilic peripheral part represented by polysaccharides.

The morphology of the formed humic films was studied by atomic force microscopy (AFM). Figure 7 shows the image of the surface of the original glass and glass treated with carbon humic modifier GV-APTS.

It can be seen from the presented images that an uneven monolayer coating with individual inclusions with an average diameter of about 100 nm and a height of up to 15 nm is observed on the treated surface. The indicated surface morphology may be due to the fact that silanol derivatives of HS are present in the solution in the form of a sol; therefore, particles of a sufficiently large size are sorbed. Judging by the thickness of the layer, the described particles acquire a flat conformation to provide the most effective binding to the surface.

Thus, we can conclude that silanol derivatives of HS have the ability to increase the hydrophobicity of the mineral surface due to the formation of a humic film, which is a favorable property in the aspect of application for the restoration of degraded soils.

Example 5

The example demonstrates an increase in the water resistance of soil aggregates treated with humic silanol derivatives. For the study, the initial HB, HB-APTS and phosphate buffer were selected. A solution of 1 g / l of the initial HV was prepared by dissolving in phosphate buffer (0.03 M, pH 6), a solution of 1 g / l of HV-APTS was prepared by sequential dissolution in KOH (3 M), acidification to pH 6 with diluted phosphoric acid and subsequent dissolution in phosphate buffer (0.03 M, pH 6).

To assess the water resistance of the aggregates, the Andrianov method was used. A soil sample of a typical chernozem under steam from an experimental site in the Kursk region in the air-dry state was sieved on sieves and a fraction with an aggregate size of 3-5 mm was taken. Filter paper was placed in a Petri dish and secured with glass weights. 50 units were taken for testing, which were evenly laid out on a Petri dish. Further, the aggregates were capillary saturated, wetting the filter paper in a Petri dish with the test solution. Left to dry in air for 24 hours. Then the aggregates were first saturated with capillary distilled water for 3 minutes, and then carefully added water to a level of 0.5 cm above the aggregates. Every minute, the number of decayed aggregates was counted. Observation was carried out for 10 minutes. Then calculated the coefficient of water resistance of soil aggregates according to the following formula:

$$K=\frac{{\displaystyle \sum _{n=\mathrm{one}}^9\left(c-a\right)}*\left(\frac{\mathrm{<figure-callout\; id="10"\; label="n"\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">n</figure-callout>}}{10}+0.05\right)+b}{c}$$

where a is the number of disintegrated units per minute,

b - the number of undecayed aggregates in 10 minutes,

C is the total number of units.

On Fig shows photographs of the experiment before and after the decay of soil aggregates. The obtained kinetic dependences are presented in Fig.9.

It can be seen from the figure that, in soil aggregates treated with silanol derivatives of GW, water resistance significantly increases. The water resistance coefficients calculated using the formula were 0.51, 0.27, and 0.22 for aggregates treated with CHS-APTES-30, H ₂ O, and CHS-K, respectively.

Example 6

An example demonstrates the restoration and improvement of the structure of degraded soils as a result of treatment with humic silanol derivatives.

Soil structure - size distribution of soil units. The agronomically valuable structure includes soil aggregates of 0.25-10 mm. One of the most important properties of the structure is water resistance - the ability of units to withstand the destructive effect of water. Thus, the more particles with sizes <0.25 mm in the soil, the more degraded the soil structure.

Therefore, soil particles with sizes <0.25 mm were used as a model substrate. Particles were obtained by dry sieving of sod-podzolic soil through a sieve <0.25 mm. As an indicator of the restoration of the degraded soil structure, the percentage of water-resistant aggregates formed under the influence of humic silanol derivatives (particles> 0.25 mm) was estimated.

25 g of 0.25 mm particles of sod-podzolic soil were added to the Petri dish, 25 ml of a solution of humic silanol derivatives were added there, the pH was adjusted to 6.8 ± 0.2, and the concentration of the derivatives was 2.5, 5, and 10 g / l. As a control, under similar conditions, the initial HS of coal was used, used for modification. In addition, a distilled water option was laid.

Petri dishes with soil were dried at room temperature in a vacuum oven until air-dry.

Then samples were taken from the prepared options (5 replicates for each option), in which the content of water-resistant aggregates was determined. To do this, the samples were carefully kneaded with a pestle with a rubber tip into structural units, weighed, passed through a 0.25 mm sieve and again weighed to determine the amount of air-dry aggregates formed. Then, a weighed portion of the obtained aggregates> 0.25 mm was placed on a sieve (0.25 mm) and saturated with capillary distilled water through wet filter paper. Saturated aggregates were immersed in water for 10 minutes, then they were passed through a 0.25 mm sieve with ten swings of the sieve at 45 ° and up and down movements of the sieve in water. The particles passing through a sieve were dried in a water bath, dried at 105 ° C in an oven, and weighed. The mass difference between the dry sieving aggregates and particles passing through a sieve during sieving in water was used to determine the number of water-resistant aggregates formed. Based on the data obtained, the percentage of water-resistant aggregates formed was calculated. All obtained averages were compared with each other by the t-criterion (at α = 0.05).

Figure 10 shows the formation of water-resistant aggregates from soil structureless particles less than 0.25 mm as a result of treatment with silanol derivatives of HS. For comparison, the formation of aggregates under the influence of the initial HS of coal used for modification is shown.

Humic silanol derivatives and initial humic substances significantly increased the formation of water-resistant aggregates in particles <0.25 mm in comparison with the version with distilled water. The average values obtained for humic silanol derivatives exceeded those for the initial HS of coal. In this case, significant differences between silanol derivatives and native HS were observed at the level of their introduction to 5 g / l. A further increase in concentration to 10 g / l offset the difference between the initial and modified HS.

Thus, it is shown that:

- humic silanol derivatives significantly increase the content of water-resistant aggregates in the model of degraded soil;

- humic silanol derivatives increase the content of water-resistant aggregates in the model of degraded soil more effectively than conventional humic substances;

- concentrations for the use of humic silanol derivatives in order to restore degraded soil should not exceed 5 g / l.

Example 7

The example demonstrates the use of silanol derivatives of HS as an ameliorant for improving the structure of the soil in a small-plot experiment.

The tests were conducted on highly cultivated sod-podzolic soil. Tillage was carried out by irrigation with solutions of the studied drugs at a concentration of 2.5 g / l. The consumption rate was 10 l / m ² . Well water was used as a control. Next, wheat was sown (500 pcs / m). Crop care included manual weeding and watering as needed. The duration of the experiment was 99 days. Before the experiment and after its completion, the content of agronomically valuable aggregates (0.25-10 mm) was determined.

It was found that during the experiment (99 days) the introduction of GV-APTS led to an increase in the soil structural coefficient, determined by the content of agronomically valuable aggregates, by 11% (Fig. 11).

The above descriptions of possible uses of the present invention so fully demonstrate the nature of the present invention that other researchers will be able to, using this knowledge, easily modify or modify the described general method for other special applications without essentially changing it. Therefore, such adaptations and modifications of the proposed approach should be considered as not containing an independent subject matter of the invention. At the same time, it goes without saying that the main purpose of the terminology or verbal expressions used in the description of this invention was to disclose the essence of the invention, while it was assumed that this could be done using other expressions without limiting the terminology used.

The described methods, materials and stages of the various claimed steps can be carried out using other approaches that will not change the essence of the invention. For example, expressions such as “using ...” or “through ...”, as well as any other phraseological descriptions of the methods used in the description of the above examples or in the description of the following claims that preceded the essence of the method, were given in order to define and cover all possible structural, physical, chemical and engineering elements and structures, as well as any methodological steps that may already exist today or be invented in the future for the implementation of fun of the names referred to in this invention, regardless of how fully equivalent they are to the above examples of applications, that is, it is allowed to use any other methods and methodological methods to achieve the above functional properties, it is assumed that all the private methods used should be interpreted in the broadest sense.

Claims (8)

1. Silica-humic derivative containing silanol groups, characterized by water solubility in an alkaline medium and the ability to irreversibly sorb on a solid substrate containing on the surface —OH groups obtained by a method involving the interaction of a humic substance with aminoalkoxysilane in an aqueous medium, while using a humic substance as a substance isolated from natural sources, and 3-aminopropyltrialkoxysilane or 1-aminohexamethylene 6-aminomethylene trialkoxis is used as aminoalkoxysilane Ilan with subsequent distillation of water and heating of the product at a temperature of 30-150 ° C. 2. The use of silica-humic derivative for the restoration of degraded soils in situ, including the introduction of a humic derivative according to claim 1 in the form of an aqueous solution on a site of degraded soil. 3. The use of the silica-humic derivative according to claim 1, wherein the humic derivative in the form of an aqueous solution is introduced either by drip irrigation or by irrigation machines. 4. The use according to claim 3, in which the humic derivative is used in the form of 0.01-10 wt.% Aqueous solution. 5. The use according to claim 3, in which the silicic acid derivative is used in the form of 0.01-10 wt.% Aqueous solution in combination with liquid and complex fertilizers. 6. The reagent for the restoration of degraded soils in situ, including the silica-humic derivative according to claim 1. 7. The reagent according to claim 6, in which the silicic acid derivative is used in the form of an aqueous solution. 8. The reagent according to claim 6, in which the silicic acid derivative is used in the form of an aqueous solution with a concentration of 0.01-10 wt.%.

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