RU2351543C1 - Method for extraction of heavy metal ions from aqueous solutions - Google Patents

Abstract

FIELD: sewage treatment facilities.

SUBSTANCE: invention is related to methods for extraction of heavy metal ions by sorption on natural cellulose-containing sorbates from solutions of complex composition, where natural or synthetic complexions are available. Method may also be used for treatment of sewage waters from food productions of different composition, and also for improvement of membrane and sorption technologies. Method includes contact of water solutions with modified polymer sorbates on the basis of cellulose, when module solution/sorbate is equal to 50-200. Modification of sorbates is done by their treatment for 15-30 s in aqueous solution of cationic polyelectrolyte with concentration of 10-25 g/l at room temperature and module of sorbate/aqueous solution of cationic polyelectrolyte equal to 10-20, with further extraction and drying at 120-130°C for 3-4 minutes. Contact of modified sorbate with aqueous solution containing heavy metal ions is realised for 20-40 minutes. Polymer sorbates on the basis of cellulose are cotton or linen fabrics.

EFFECT: method provides for significant cost reduction and simplification of process at higher extent of heavy metal ions extraction.

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Description

The invention relates to methods for the extraction of heavy metal ions by sorption on natural cellulose-containing sorbents from solutions of complex composition in which natural complexones (lactic, citric, tartaric, oxalic acid, α-amino acids, etc.) or synthetic complexones (Trilon B, etc.) are present , including wastewater of food production of various compositions, and can be used to improve membrane and sorption technologies.

BACKGROUND

There is a method of wastewater treatment of industrial enterprises from heavy metals, in particular from copper ions, by sorption on sawdust treated with 4-methyl-8-oxo-5-azadecadiene-3,9-OH-2 with a sawdust-reagent mass ratio of 1 : 0.05 ÷ 0.1 [a.s. USSR 1819669, MKI ⁵ V 01020/22. A method of producing a sorbent for wastewater treatment of copper, // Timofeeva S.S., Kukharev B.F., Stankevich V.K., Klimenko G.R. - No. 4911863/05; Claim 05/15/91; Publ. June 7, 93, Bull. No. 21]. However, this method of modifying sawdust is uneconomical, since it implies the use of an expensive reagent in an amount of 5-10% by weight of the sorbent, and also leads to environmental pollution.

A known method for the separation of heavy metal ions on cellulose derivatives containing amino acid residues [Toshihiko Sato, Kazuhiro Karatsu, Hiromi Kitamura, Yasuo Ohno. Synthesis of cellulose derivatives containing amino acids residues and their adsorption of metal ions // Sen-i gakkaishi, J. Soc. Fiber Sci. and Technol, Jap .- 1983. V.39. N 12. P.519-524.]. As a result of the use of such cellulose polymers with grafted amino acid groups, the sorption capacity of cellulose-based sorbents increases from 4.7-17.3% for untreated microcrystalline cellulose to 17.9-99.8% on various samples of amino acid derivatives of cellulose upon sorption of various metals : Cu (II), Zn (II) and Cd (II). The best results were obtained in the case of extraction of copper, zinc and cadmium ions on lysine and cysteine - cellulose from 0.2 mmol / l of chloride solutions of these metals.

However, the samples of amino acid derivatives of celluloses used in this method are scarce and expensive sorbents that were synthesized from cellulose isocyanate (obtained by heating for 4 hours a mixture of microcrystalline cellulose and 2,4-toluene-diisocyanate in dimethyl sulfoxide at 60 ° C in a nitrogen atmosphere) and amino acids at 30 ° C for 2 hours. In addition, the process of extraction of heavy metal ions from aqueous solutions using cellulose derivatives containing amino acid residues was carried out at a temperature of 30 ° C for 3 hours.

The closest in technical essence and the achieved result, that is, the prototype, is a method for extracting heavy metal ions from aqueous solutions by contacting them with polymer sorbents containing a cellulose component and amino acid residues with a solution / sorbent module equal to 50-200 [T. Nikiforova E. ., Bagrovskaya N.A., Lilin S.A., Kozlov V.A. The method of extraction of heavy metal ions from aqueous solutions. RF patent №2258560. Publ. in BI No. 23 of 08/20/2005]. In this case, the secondary products of the processing of oilseeds - oilseed meal or cake, pretreated in aqueous solutions of enzymes with a solution / sorbent module of 5-50 and an enzyme concentration of 1-10% by weight of the sorbent for 1-3 hours at a temperature of 25 are used as a polymer sorbent -40 ° C, and the contacting of the treated sorbent is carried out for 5-20 minutes at room temperature.

As a result of the use of such sorbents, the degree of extraction of Cu (II), Zn (II) and Cd (II) ions for various individual and mixed samples of meal and cake was 78.3-99.9%.

The disadvantages of the prototype are:

- low efficiency of the method (the degree of extraction of 25.3-74.6%) when cleaning aqueous solutions of complex composition, which are multicomponent systems in which natural and synthetic complexones are present. The removal of heavy metal ions from such solutions is difficult, since the substances contained in them interact with metal cations to form strong complexes held in solution;

- the use of expensive and scarce reagents — enzymes and enzyme preparations — for pre-treatment of sorbents (100 mg of lipase obtained from Pseudomonada Cepacia costs 61.21 euros [Sigma. 2002-2003]); if lipase is produced by domestic industry, the enzyme preparation Bi mix is a prototype developed by genetic engineering at the Department of Enzymology of Moscow State University.

SUMMARY OF THE INVENTION

The objective of the invention is to provide a method for the extraction of heavy metal ions from aqueous solutions, allowing:

- clean solutions of complex nature, in which there are natural complexones (lactic, citric, tartaric, oxalic acids, α-amino acids, etc.) or synthetic complexones (Trilon B, etc.);

- increase the degree of extraction;

- reduce the cost of pre-treatment of the sorbent.

The problem is solved by creating a method for the extraction of heavy metal ions from aqueous solutions by contacting them at room temperature with modified cellulose-based polymer sorbents with a solution / sorbent module of 50-200, while sorbents are modified by processing them for 15-30 s in an aqueous solution of a cationic polyelectrolyte with a concentration of 10-25 g / l at room temperature and a sorbent / aqueous solution of a cationic polyelectrolyte module equal to 10-20, followed by extraction and drying m at 120-130 ° C for 3-4 minutes, and the contacting of the modified sorbent with an aqueous solution containing heavy metal ions is carried out for 20-40 minutes, while cotton or linen fabrics are used as polymer sorbents based on cellulose.

VPK-402 cationic polyelectrolyte is a high molecular weight cationic polymer with a linear cyclic structure obtained by radical polymerization of dimethyldiallylammonium chloride monomer, which, in turn, is made from allyl chloride and dimethylamine by heating in an alkaline medium. The molecular weight of the polymer is approximately 3-10 ⁵ [TU 2227-184-00203312-98].

Appearance - colorless to yellow color, homogeneous in consistency, liquid without impurities; mass fraction of the main substance - not less than 25%; mass fraction of sodium chloride - not more than 10%; viscosity - not less than 2 cm ³ / s; pH 5-8.

Chemical formula:

Cotton or linen fabrics are used as polymer sorbents: calico (article 261), or calico (article 431), or satin (article 547), or flannel (article 4C-59).

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

Example 1

10 g of coarse calico (article No. 261) is poured into 100 ml of an aqueous solution (module 10) at room temperature containing 10 g / l of VPK-402 cationic polyelectrolyte, incubated for 30 s at room temperature, squeezed and dried for 3 min at 130 ° С .

The treated sorbent is poured into 0.5 L of an aqueous solution at room temperature (module 50) containing 0.15 mmol / L of copper ions and 10 g / L of lactic acid. After 20 minutes, the solution is filtered off and the content of Cu (II) ions is determined in the filtrate. The concentration of copper ions after three sorption cycles was 0.00015 mmol / L (99.9% recovery).

Example 2

10 g of calico (article No. 43) is poured into 150 ml of an aqueous solution (module 15) at room temperature containing 15 g / l of VPK-402 cationic polyelectrolyte, incubated for 25 s at room temperature, squeezed and dried for 3.5 minutes at 125 ° C.

The treated sorbent is poured into 1 l of an aqueous solution at room temperature (module 100) containing 0.15 mmol / l of zinc ions and 10 g / l of tartaric acid. After 25 minutes, the solution was filtered and the content of Zn (II) ions was determined in the filtrate. The concentration of zinc ions after three cycles of sorption was 0.0003 mmol / L (99.8% recovery).

Example 3

10 g of satin is poured into 200 ml of an aqueous solution (module 20) at room temperature containing 20 g / l of VPK-402 cationic polyelectrolyte, incubated for 20 s at room temperature, squeezed and dried for 4 min at 120 ° C.

The treated sorbent is poured into 750 ml of an aqueous solution at room temperature (module 75) containing 0.15 mmol / L of cadmium ions and 10 g / L of oxalic acid. After 30 minutes, the solution was filtered and the content of Cd (II) ions was determined in the filtrate. The concentration of cadmium ions after three sorption cycles was 0.00045 mmol / L (99.7% recovery).

Example 4

10 g of flannel is poured into 200 ml of an aqueous solution (module 20) at room temperature containing 25 g / l of VPK-402 cationic polyelectrolyte, incubated for 15 s at room temperature, squeezed and dried for 4 min at 125 ° C.

The treated sorbent is poured into 2 L of an aqueous solution at room temperature (module 200) containing 0.15 mmol / L of copper, zinc and cadmium ions and 10 g / L of citric acid. After 40 minutes, the solution is filtered off and the content of Cu (II), Zn (II) and Cd (II) ions is determined in the filtrate. The concentration of copper, zinc and cadmium ions after three sorption cycles was 0.0012, respectively; 0.014 and 0.031 mmol / L (the degree of extraction of Cu (II), Zn (II) and Cd (II) ions is 99.2, 90.7 and 79.3%).

To assess the effectiveness of the prototype method and comparison with the claimed invention, experiments were conducted on the extraction of heavy metal ions from solutions of complex nature, in which complexons are present.

The results of the experiments are presented in the table.

Thus, from the data given in the table it follows that the proposed method allows us to solve the problem, namely, to extract heavy metal ions by sorption from aqueous solutions, while reducing the cost of processing the sorbent: instead of expensive enzyme preparations, use affordable inexpensive cationic polyelectrolyte VPK-402, clean solutions of complex nature in which natural or synthetic complexones are present (lactic, citric, tartaric, oxalic acids, etc.); while achieving high degrees of purification: 79.3-99.9%. In addition, the use of tissue sorbents seems more convenient in comparison with finely dispersed sorbents.

EXAMPLES Sorbent Modifying agent The degree of extraction,% The cost of the modifying agent Cu ²⁺ Zn ²⁺ Cd ²⁺ one. calico VPK-402 99.9 - - 40 rubles per 1 kg 2. calico VPK-402 - 99.8 - also 3. satin VPK-402 - - 99.7 also four. flannel VPK-402 99,2 90.7 79.3 also PROTOTYPE mustard meal B ₁ mix 74.6 - - prototype linen meal lipase - - 68,4 61.21 euros per 100 mg linseed and mustard cake B ₁ mix and lipase - 72.1 - also mustard meal and linen meal B ₁ mix and lipase 55,2 34.8 25.3 also

Claims (1)

The method of extraction of heavy metal ions from aqueous solutions by contacting them at room temperature with modified cellulose-based polymer sorbents with a solution / sorbent module of 50-200, characterized in that the sorbents are modified by treating them for 15-30 s in an aqueous solution cationic polyelectrolyte with a concentration of 10-25 g / l at room temperature and a sorbent / aqueous solution of a cationic polyelectrolyte module equal to 10-20, followed by extraction and drying at 120-130 ° C for 3-4 minutes, and Attacking of the modified sorbent with an aqueous solution containing heavy metal ions is carried out for 20-40 minutes, while cotton or linen fabrics are used as polymer sorbents based on cellulose.