Method of obtaining anion-exchange fibre material, capable of extracting chromium (vi)

FIELD: chemistry.

SUBSTANCE: invention can be used for extracting metal ions, purifying waste and industrial solutions from toxic metal ions. The method of obtaining anion-exchange fibre material involves reacting activated polyacrylonitrile fibre nitron and 30-70 wt % modifying agent - mixture of diethanolamine with 10-30 wt % hexamethylenediamine in an aqueous 5% solution of dimethylformamide. Nitron is activated in a 3-6% aqueous alkaline solution for 3-5 minutes at 90-95C.

EFFECT: invention makes it easier to obtain fibrous anionite and can be used for effective purification waste water from leather industry and electroplating plants from chromium (VI) ions, and for concentrating and separating chromates from industrial solutions.

1 tbl, 4 ex

 

The invention relates to the field of macromolecular chemistry, in particular to the creation of new fibrous ion-exchange materials have found application in hydrometallurgy for the extraction of metal ions, wastewater and industrial solutions of toxic metal ions.

Known methods for producing anion exchange fibrous materials by modification of polyacrylonitrile fiber Nitron hydroxylamine and hydrazine (kulinskaya D.A., Yemets L.V., Kotecki CENTURIES, wolf L.A. Modification of polyacrylonitrile fibres on the basis of hydroxylamine. // Chem. the fiber. - 1976. No. 6. - P.21-22. Karaivanova S., Dimov, K., Badev A. Modification of polyacrylonitrile fibers hydrazinehydrate // Chem. and ind - 1983. No. 1).

The disadvantage of these fibers is that due to the destruction in acidic media in the presence of strong oxidants, they are not able to extract ions of chromium (VI) from solutions.

The closest in technical essence to the present invention is a method of obtaining anion exchange fibrous material (resin) of the acrylic fiber Nitron by modifying it with an aqueous solution of hydrazine hydrate is added (Gafurov D.A., Musayev U.N. in., The Khakimzhanov BS, Mukhamadiev MG Synthesis of ion-exchange fibrous materials based on the Nitron and their applications // journal of Tashkent state University, Tashkent. - 1999. No. 2. - P.27-29).

It is not the lump is obtained in this way anion exchanger is that he is not able to clean industrial water from hexavalent chromium ions.

The objective of the invention is making available a simplified method of producing fibrous anion exchanger, allowing to extract from aggressive acidic solutions of metal ions, in particular ions of hexavalent chromium.

The problem is solved by the method of obtaining the anion exchange fibrous material including the interaction of polyacrylonitrile (PAN) fiber Nitron and the modifying agent (MA) in aqueous solution, in which in contrast to the prototype as the modifying agent, a mixture of diethanolamine (deja) and diamine (HMDA) containing the latter in the mixture (10-30) wt.% and concentration of the mixture (30-70) %, and the fiber Nitron before modification activate (3-6)% aqueous solution of alkali within (3-5) minutes at a temperature of 90-95C., and the reaction of modifications carried out in 5% aqueous solution of dimethylformamide (DMF).

HMDA in this reaction is used as a crosslinking agent, preventing the dissolution of the fiber. In this way possible to obtain the ion-exchange fiber, applicable to industrial wastewater treatment plants from hexavalent chromium ions. Pre-activated PAN fibers with alkali solution is carried out for improving the reaction efficiency.

The method of obtaining fiber is East anion-exchange material is as follows.

The modification reaction is carried out in a 5% aqueous solution of dimethylformamide, DMF. Activated fiber is placed in a reactor containing a solution of MA 30-70%, the solution is heated at a temperature of 95-100C for 1-3 hours, while the module of the bath is 50.

The modified fiber is extracted, washed with water and dried to air-dry state. The static exchange capacity (SOY) Hcl is 1 to 3 mEq/g of fiber.

In the IR spectra of modified activated samples POLYACRYLONITRILE fibres in comparison with the original modified fibers, a decrease in the intensity of absorption band at 2240 cm-1corresponding to the stretching vibrations of nitrile groups, new absorption bands at 3500-3600 cm-1corresponding to the stretching vibrations of-NH and-Oh groups, at 3370 cm-1corresponding to-C=NH groups, and at 1660 cm-1related to the stretching vibrations of C=O carboxyl group. The presence of a strong base ajdinovic groups promotes complex formation with ions of hexavalent chromium.

On the basis of IR spectroscopic studies of the structure of the ion exchanger can be represented by the following scheme:

To prove the ability of the resulting anion exchange resin to adsorb ions, hexavalent chromium was determined dynamic exchange capacity (DOE) Sora is having on bichromate ions. The obtained data are presented in the table.

Examples of methods of obtaining fibrous anion exchanger:

1. The Nitron fiber treated with 4% aqueous sodium hydroxide solution at 90C for 3 minutes. Then a sample of 0.5 g of activated fibers are placed in a reactor containing 25 ml of 30% solution of MA in 5% aqueous solution of DMF, and heated for 3 hours at a temperature of 95-100C. the resulting fiber is drained, washed with water and dried to air-dry state. The SOYA Hcl is 1.1 mEq/g of fiber.

2. The Nitron fiber treated with 4% aqueous sodium hydroxide solution at 90C for 3 minutes. Then a sample of 0.5 g of activated fibers are placed in a reactor containing 25 ml of 50% solution of MA in 5% aqueous DMF, and heated for 2 hours at a temperature of 95-100C. the resulting fiber is drained, washed with water and dried to air-dry state. The SOYA Hcl is 1.9 mEq/g of fiber.

3. The Nitron fiber treated with 4% aqueous sodium hydroxide solution at 90C for 3 minutes. Then a sample of 0.5 g of activated fibers are placed in a reactor containing 25 ml of 60% solution of MA in 5% aqueous DMF, and heated for 2 hours at a temperature of 95-100C. the resulting fiber is drained, washed with water and dried to air-dry state. The SOYA Hcl is 2.6 mEq/g of fiber.

4. The Nitron fiber treated with 4% aqueous sodium hydroxide solution at 90 the C for 3 minutes. Then a sample of 0.5 g of activated fibers are placed in a reactor containing 25 ml of 70% solution of MA in 5% aqueous DMF, and heated for 1.5 hours at a temperature of 95-100C. the resulting fiber is drained, washed with water and dried to air-dry state. The SOYA Hcl is 3.0 mEq/g of fiber.

Table
Is SOY, THE known and obtained sorbents
The SOYA Hcl, mg-EQ/gThe interval of pHTHE K2CR207(mg/g
The placeholder31-80
Example 11,11-8120
Example 21,91-8200
Example 32,61-8250
Example 43,01-8350

As can be seen from the data that the Litsa river, the anion exchange resin obtained by modification of acrylic fibre mixture deja, HMDA, unlike the prototype effectively remove chromium ions from solutions in a wide range of pH. The resulting ion is able to regenerate 5% solution of KOH. They can withstand ten times the repeat loop regeneration - sorption without practical changes in the capacitance, which indicates their great chemical resistance in strongly acidic solutions in the presence of oxidizing agents.

Thus, the use of the present invention allows to easily obtain a fibrous anion exchange resin of the type which can be used for the effective treatment of wastewater leather production and electroplate workshops from hexavalent chromium ions, as well as for the concentration and extraction of chromium from industrial solutions.

The method of obtaining the anion exchange fibrous material including the interaction of acrylic fiber Nitron and the modifying agent in an aqueous solution, characterized in that the modifying agent is a mixture of diethanolamine and diamine containing the latter in a mixture of 10-30 wt.% and concentration of the mixture of 30-70%, and the fiber Nitron before modification activate 3-6%aqueous alkali solution for 3-5 min at a temperature of 90-95C, and the modification reaction is carried out in 5%aqueous RA the creators of dimethylformamide.



 

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2 ex

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EFFECT: optimized manufacture conditions.

2 ex

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