RU2325230C1 - Method of obtaining selective sorption and ion-exchange materials - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: said utility invention relates to the field of ion exchange with complexing and chelation, and may be used in the hydrometallurgy of non-ferrous, rare, and noble metals, in water treatment and water purification processes, the chemical industry, and for obtaining high purity substances. The method of obtaining selective sorption and ion-exchange materials includes treatment of amine-containing raw materials with formaldehyde and hypophosphorous acid. As the amine-containing raw materials, a product of enzymatic hydrolysis of natural proteins is used, i.e. peptides with a molecular weight of 700-1000 g/mol, and individual amino acids in the form of a 15-25% water solution. The synthesis process is carried out at 60-70°C.

EFFECT: simplification of technology; increased selectivity of synthesised products to required metal ions.

2 cl, 3 ex

Description

The invention relates to the field of ion exchange with complexation, chelating and can be used in hydrometallurgy of non-ferrous, rare and noble metals, in the processes of water treatment and water purification, in the chemical industry, as well as for obtaining substances of high purity.

Most of the known ion-exchange and sorption materials exhibit reduced selectivity in the separation of a mixture of metal ions, which is determined by the steric conformation of the active centers of ion exchangers and sorbents, the number and type of complexing and chelating functional groups in the structure of these materials. In some cases, efficiency is required in the extraction, concentration of the desired metal from highly diluted aqueous solutions. At the same time, environmental protection requirements put forward conditions for safe methods for the disposal of waste materials, the use of low-waste synthesis, operation, and recycling technologies.

Chelating phosphorus-containing cation exchangers are known, including the products of the interaction of an amine-containing resin with primary and secondary amines and the subsequent reaction of the laminated resin with phosphonoalkylation agents (EP 0065120 A1, C08F 8/40, 11.24.1982).

The disadvantages of these cation exchangers are the multi-stage synthesis process, resource and energy intensity of the technology, reduced selectivity of the resulting substances and materials to polyvalent metal ions, low sorption efficiency in the extraction of trace amounts of metal, which limits their use.

A known method of producing a chelating resin based on chitosan, comprising treating chitosan sequentially with glycidyl ether of aliphatic polyols, polyethyleneimine, aromatic acid anhydride in a polar solvent and then acetic anhydride (JP 2229831, B01J 45/00, 09/12/1990).

The disadvantages of this method are the use of toxic combustible organic solvents in the process, the complexity of the synthesis, deficiency of chitosan, which limits the scope of use of the product.

Known phosphorus chelating cation exchange resin as uranyl cation sorbent comprising a polymer containing pendant phosphono, and fosfonofenil- fosfonoalkilfenilnye groups obtained from the reaction of copolymerization of styrene, divinylbenzene and vinilfosfonatov, followed by hydrolysis of the intermediate copolymer processes, alkylation of the benzene nuclei of PCl ₃ and PCl ₂ further hydrolysis - derivatives to compounds with side phosphono groups (EP 0461822 A2, C08F 8/12, 12/18/1991).

The disadvantages of this cation exchange resin are the scarcity of the starting reagents (vinyl phosphonates) for its preparation, the use of aggressive, correlating substances, the difficulty of obtaining a constant composition product, and the reduced selectivity of the materials obtained with respect to d-elements, which reduces the competitiveness of these materials.

A known method of producing a phosphorus-containing cation exchanger, comprising the amination of halogenomethyl groups of an aromatic polymer and subsequent phosphonomethylation. In this case, a mixture of mono- and polyamines, in which the monoamine content is 20-70 mol% (US 5208264 A1, C08F 8/40, 05/04/1993), is used as an aminating agent.

The disadvantages of this method are the low degree of conversion during amination, the complexity of the synthesis process, the need for an intermediate stage of distillation of solvent residues from the polymer, the lack of selectivity for d-elements in the synthesized materials, for example, copper, nickel, zinc, which is a consequence of the use of an aromatic polymer in the synthesis , which limits the industrial use of these sorbents and ion-exchange materials.

Known cation exchange resin containing groups of polyphosphoric acid, and a method for its preparation, comprising suspension polymerization in polymer particles containing polyphosphoric acid, glycidyl-containing monomer and a crosslinking monomer, in an organic solvent not miscible with water, and subsequent interaction of the glycidyl groups of the resulting polymer particles with the chain introduced polyphosphoric acid (JP 2000210572, B01D 15/08, 08/02/2000).

The disadvantages of this cation exchange resin and its production method are the low yield of the product and a large amount of wastewater requiring treatment, which limits the use of this method and the resulting materials in industry.

Polymer resins are known containing polyamide ligands and methods for using them to remove, separate and / or concentrate target metal ions from solutions, including reaction products of hydroxymethylated polyamide ligands with one or more reagents selected from classes of compounds such as polymerization agents, crosslinking agents or combinations thereof (US 2002/0042495 A1, C08G 12/04, 04/11/2002).

The disadvantages of these materials are the complexity of controlling the process of their synthesis, its long duration and the formation of by-products, which complicates the industrial production of this material and limits its use.

The closest is the method of producing ion exchangers by treating aliphatic polyamines with formaldehyde and phosphoric acid. At the same time, the technology is simplified and the sorption ability of ion exchangers to copper, silver, manganese is increased. The phosphorus content in the synthesized substances reaches 21.1%, nitrogen - 10.7%. The coefficient of swelling in water is in the range of 2.1-2.8 ml / ml. Static exchange capacity of 0.1 N. 6.2 mg Naq / g NaOH solution. The synthesized ion exchangers have a high complexing ability with respect to copper (II) ions, reaching 3.5-4.0 meq / g at pH 4.2. The distribution coefficient for the extraction of manganese (II) ions from a slightly alkaline solution (pH8-10) with a concentration of manganese 3.3 · 10 ^-7 g / l is 10 ⁴ -10 ⁵ , while for cobalt (II) - 10 ² , and for iron (III) - 10 ³ , which indicates selectivity with respect to manganese (II) ions (SU 575363, С08G 79/04, 10/05/1977).

The disadvantage of this method is the increased consumption of reagents, a strongly acidic environment, harsh temperature synthesis conditions (90-100 ° C), which leads to a product with a heterogeneous composition and properties.

The objective of the proposed technical solution is to develop a technologically advanced method for producing selective sorption and ion-exchange materials, which allows to obtain a new complex-forming and chelating polymer product on an industrial scale, which can be used for the selective extraction, concentration and separation of transitional, heavy metal ions in the mining and processing, chemical industry, in the processes of water treatment and water purification, as well as for obtaining substances of high purity.

The technical result is the use of a product of enzymatic hydrolysis of natural proteins - peptides as an amine-containing raw material for the synthesis of ion-exchange materials and sorbents, which leads to a simplification of the production technology and increase the selectivity of the synthesized products in relation to the required metal ions, which improves the complex of consumer properties of these materials.

The technical result is achieved in a method for producing selective sorption and ion-exchange materials, including the processing of amino-containing raw materials with formaldehyde and phosphoric acid, and the product of enzymatic hydrolysis of natural proteins — peptides with a molecular weight of 700-1000 g / mol and individual amino acids — is used as an amino-containing raw material. as a 15-25% aqueous solution.

The claimed technical solution in comparison with the prototype provides for the use of the product of enzymatic hydrolysis of natural proteins - peptides as an amino-containing raw material for the synthesis of sorption and ion-exchange materials, which is a significant advantage, since the production technology is simplified and the selectivity of the materials, the static ion-exchange and sorption capacities are increased, and distribution coefficient during the extraction of metal ions, which positively affects the consumer complex stv materials.

The process of synthesis of selective ion-exchange and sorption materials is described by the formation of polyproteinylmethylenephosphinic acid and its derivatives during the treatment of peptides with formalin and sodium hypophosphite in an acidic environment. Reactions proceed along nucleophilic groups of peptides. Depending on the amino acid composition of the starting proteins, the following nucleophilic reaction centers may be included in the peptides: terminal and side amino groups, amide groups, guanidyl groups, imidazole groups, phenolic groups, indole groups. At different rates, these reaction centers participate in phosphonomethylation reactions, leading to the formation of branched and crosslinked polymer products, the three-dimensional framework of which is built from chains containing units with chelating phosphine groups. It is assumed that this reaction proceeds in 2 stages; in the first, formaldehyde is attached at nucleophilic groups to form methylol derivatives. Further, phosphoric acid formed in the reaction mixture during the interaction of sodium hypophosphite with hydrochloric acid reacts with these derivatives with the release of water, forming the products of the phosphonomethylation reaction. The high reactivity of the peptides allows one to obtain selective sorption and ion-exchange materials under mild conditions in a single step without the use of organic solvents with good yields of target products.

An increase in the selective sorption capacity and distribution coefficient during the extraction of the desired metal ion from the solution is associated with the high complexing and chelating ability of polyproteinylmethylenephosphonic acid, which can be explained by the ability of this crosslinked copolymer to form a complete saturated ligand contour, as well as high-strength hydrogen and polynuclear complexes with metal ions which in turn is determined by the synergistic action of the peptide fragment of the copolymer capable of to accept the necessary steric conformation in the presence of metal ions and chelatogenic phosphine groups forming strong coordination chemical bonds due to the interaction of electron shells and the redistribution of electronic densities of complexing metals and macromolecular ligands. This is the fundamental difference between these materials and the method of production thereof from the materials and method of preparation proposed in the prototype.

The use of peptides with a number average molecular weight of less than 700 g / mol is impractical, since it reduces the selectivity and sorption capacity of ion-exchange and sorption materials, which can be explained by the too high density of crosslinking of macromolecules, which makes diffusion of sorbed ions to complexation centers more difficult and the possibility of formation active centers of the required spatial structure.

The use of peptides with a number average molecular weight of more than 1000 g / mol is also impractical, since it reduces the osmotic stability and decreases the hydrolytic stability of sorption and ion-exchange materials, which reduces the service life of these materials.

The use of peptides with a concentration of over 25% for the synthesis of an aqueous solution is difficult due to the increased viscosity and high concentration of micellar structures, which leads to a product that is heterogeneous in composition and properties.

The use of peptides with a concentration of less than 15% for the synthesis of an aqueous solution leads to excessive dilution of the reaction mixture, a decrease in the reaction rate, an unreasonable increase in the volume of spent solutions, and therefore cannot be recommended.

The optimal temperature range for the process is 60-70 ° C, where the highest rate of formation of the target products is observed. An increase in temperature above 70 ° C leads to an increase in the occurrence of adverse reactions in the system, disproportionation of phosphoric acid, acid hydrolysis of peptide bonds, which leads to a product with a reduced complex of sorption and physico-mechanical properties. Lowering the temperature below 60 ° C increases the duration of the process, which reduces the productivity of technological equipment.

The method is as follows.

The product of enzymatic hydrolysis of natural proteins - peptides with a molecular weight of 700-1000 g / mol and individual amino acids in the form of a 15-25% aqueous solution is treated with formaldehyde (37% formalin) and phosphorous acid formed in the reaction mixture in the interaction of sodium hypophosphite with hydrochloric acid acid, in the temperature range of 60-70 ° C. The process is carried out with stirring of the reaction mass at a constant temperature for 2-3 hours. The resulting insoluble polymer in the form of flakes is separated from the mother liquor by filtration or centrifugation. Next, the resulting product is washed successively with water, 5% aqueous sodium hydroxide solution, 5% hydrochloric acid solution and again with water. Excess moisture is removed by centrifuging the resulting product to a predetermined degree of moisture.

Peptides with a molecular weight of 700-1000 g / mol are obtained by enzymatic hydrolysis of natural proteins (collagen, soy protein, etc.) using known proteolytic enzymes (pepsin, trypsin, chymotrypsin). When using trypsin, the process is as follows. Trypsin is introduced into an aqueous solution of a protein with a concentration of 10-15% at a temperature of 36-38 ° C in a mass ratio of trypsin: protein equal to 1: 100 in terms of dry matter. The pH of the medium is maintained in the range of 7.5-7.8. Hydrolysis is carried out at a constant temperature, gentle stirring for 2-3 hours. After hydrolysis, the reaction mass is heated to 70-80 ° C and maintained at this temperature for 15-20 minutes in order to stop the process by thermal inactivation of the enzyme. Next, the solution is concentrated by known methods at a temperature not exceeding 60 ° C and used in the synthesis of ion-exchange and sorption materials. The degree of hydrolysis and molecular weight of the resulting peptides is determined by the method of formol titration, carried out by a known method.

Example 1. To 20 g of a 15% solution of peptides with a number average molecular weight of 750 g / mol (0.004 mol), 4.24 g of sodium hypophosphite monohydrate (0.040 mol) is added with stirring. The solution is heated to a temperature of 60 ° C. After dissolution of sodium hypophosphite, 0.9 ml (0.010 mol) of concentrated hydrochloric acid is added dropwise into the reaction mixture with stirring, and immediately thereafter 1.5 ml (0.020 mol) of 37% formalin is added. After 10-15 minutes, the formation of flakes of an insoluble polymer (polyproteinylmethylenephosphonic acid) begins. The reaction mixture is stirred at a constant temperature for 2 hours, after which the flakes of the resulting product are separated from the cooled mother liquor by filtration or centrifugation. Next, the resulting product is washed successively with water, 5% aqueous sodium hydroxide solution, 5% hydrochloric acid solution and again with water. Excess moisture is removed by centrifugation of the resulting product. Receive ion-exchange and sorption material with a yield of 92%. The phosphorus content in the obtained polymer by weight is 2.8%, water absorption by weight is 150%. IR spectrum, ν, cm ^-1 : 3700-3500; 2600-2560; 1600-1560; 1650-1620; 1175. The static exchange capacity of 0.1 N. 6.5 mg Naq / g NaOH solution. Static sorption capacity for ions of Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Co ²⁺ from 0.1 N. solutions of metal chlorides at pH 4.0, respectively, 5.1; 4.9; 2.8; 2.7 mgEq / g The distribution coefficients of these ions from solutions with a concentration of (1-2) · 10 ^-4 mol / L at pH 9 are 10 ⁶ -10 ⁵ for cations Cu ²⁺ , Zn ²⁺ and 10 ⁴ -10 ³ for cations Ni ²⁺ , Co ²⁺ , which indicates an increased selectivity of the obtained materials with respect to copper and zinc.

Example 2. To 20 g of a 15% solution of peptides with a number average molecular weight of 990 g / mol (0.003 mol), 3.21 g of sodium hypophosphite monohydrate (0.030 mol) is added with stirring. The solution is heated to a temperature of 70 ° C. After dissolution of sodium hypophosphite, 0.7 ml (0.008 mol) of concentrated hydrochloric acid is added dropwise into the reaction mixture with stirring, and immediately thereafter 1.1 ml (0.015 mol) of 37% formalin are added. After 5-7 minutes, the formation of flakes of an insoluble polymer (polyproteinylmethylenephosphonic acid) begins. The reaction mixture is stirred at a constant temperature for 2 hours, after which the flakes of the resulting product are separated from the cooled mother liquor by filtration or centrifugation. Next, the resulting product is washed successively with water, 5% aqueous sodium hydroxide solution, 5% hydrochloric acid solution and again with water. Excess moisture is removed by centrifugation of the resulting product. Receive ion-exchange and sorption material with a yield of 86%. The phosphorus content in the obtained polymer by weight is 1.3%, water absorption by weight is 270%. IR spectrum, ν, cm ^-1 : 3700-3500; 2600-2560; 1600-1560; 1650-1620; 1175. The static exchange capacity of 0.1 N. a solution of NaOH 4.5 mg · equiv / g. Static sorption capacity for ions of Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Co ²⁺ from 0.1 N. solutions of metal chlorides at pH 4.0, respectively, 4.4; 4.1; 2.0; 1.9 mgEq / g The distribution coefficients of these ions from solutions with a concentration of (1-2) · 10 ^-4 mol / L at pH 9 are 10 ⁶ -10 ⁵ for cations Cu ²⁺ , Zn ²⁺ and 10 ⁴ -10 ³ for cations Ni ²⁺ , With ²⁺ .

Example 3. To 20 g of a 25% solution of peptides with a number average molecular weight of 750 g / mol (0.005 mol), 5.35 g of sodium hypophosphite monohydrate (0.051 mol) is added with stirring. The solution is heated to a temperature of 60 ° C. After dissolution of sodium hypophosphite, 1.1 ml (0.013 mol) of concentrated hydrochloric acid is added dropwise into the reaction mixture with stirring, and immediately thereafter 1.9 ml (0.025 mol) of 37% formalin are added. After 7-10 minutes, the formation of flakes of an insoluble polymer (polyproteinylmethylenephosphonic acid) begins. The reaction mixture is stirred at a constant temperature for 2 hours, after which the flakes of the resulting product are separated from the cooled mother liquor by filtration or centrifugation. Next, the resulting product is washed successively with water, 5% aqueous sodium hydroxide solution, 5% hydrochloric acid solution and again with water. Excess moisture is removed by centrifugation of the resulting product. Receive ion-exchange and sorption material with a yield of 97%. The phosphorus content in the obtained polymer by mass is 3.0%, water absorption by mass is 180%. IR spectrum, ν, cm ^-1 : 3700-3500; 2600-2560; 1600-1560; 1650-1620; 1175. The static exchange capacity of 0.1 N. NaOH solution 6.8 mEq / g. Static sorption capacity for ions of Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Co ²⁺ from 0.1 N. solutions of metal chlorides at pH 4.0, respectively, 5.3; 5.1; 3.0; 2.8 mEq / g. The distribution coefficients of these ions from solutions with a concentration of (1-2) · 10 ^-4 mol / L at pH 9 are 10 ⁶ -10 ⁵ for cations Cu ²⁺ , Zn ²⁺ and 10 ⁴ -10 ³ for cations Ni ²⁺ , Co ²⁺ .

Thus, the use of the product of enzymatic hydrolysis of natural peptide proteins with a molecular weight of 700-1000 g / mol as an amine-containing raw material for the synthesis of sorption and ion-exchange materials makes it possible to obtain materials that are promising to be used in hydrometallurgy of non-ferrous, rare and noble metals, in water treatment processes and water treatment, chemical industry, as well as for obtaining substances of high purity. In addition, selectivity, ion-exchange and sorption capacity are increased, which improves the consumer properties of these materials. The manufacturing process is simple, does not require additional equipment to existing in the industry.

Claims (2)

1. A method of obtaining selective sorption and ion-exchange materials, including the processing of amino-containing raw materials with formaldehyde and hypophosphorous acid, characterized in that the product of enzymatic hydrolysis of natural proteins — peptides with a molecular weight of 700-1000 g / mol and individual amino acids — is used as the amino-containing raw material 15-25% aqueous solution. 2. The method according to claim 1, characterized in that the production process is carried out in a temperature range of 60-70 ° C.