RU2260019C1 - Method for preparing sorbent of fibrous structure - Google Patents

Abstract

FIELD: sorbents.

SUBSTANCE: invention relates to technology for preparing sorbents with fibrous structure by using waste of industrial manufacture. Method involves treatment of fibrous matrix from waste of tanning leather chips with polyelectolyte an aqueous solution obtained by alkaline hydrolysis of polyacrylonitrile or copolymer based on thereof. Prepared sorbent shows the improved capacity for extraction of different components from different aqueous media.

EFFECT: improved preparing method, improved and valuable properties of sorbent.

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Description

The invention relates to the field of creating inexpensive sorbents of a fibrous structure using industrial wastes.

A known method of introducing ionic groups into the matrix of the fibrous structure, for example into cellulose fibers, by treating them with aqueous solutions of polyelectrolyte, in particular polyethyleneimine (PEI) (V. V. Lapin and others. On the interaction of polyethyleneimine (PEI) with cellulose fibers. 1977, t. 70 No. 9, p. 2079-2084).

PEI sorption is irreversible, and with the increase in the number of carboxyl groups in cellulose, the amount of absorbed polyelectrolyte increases. However, the sorption properties of such materials are low.

Closest to the proposed technical essence is a method for producing a sorbent of a fibrous structure, in which the amination of carboxylated polyacrylonitrile fibers is carried out by treating them with aqueous PEI solutions (Ratushnyak IB et al. Ion-exchange polyacrylonitrile fibers containing polyethyleneimine. "Chemical fibers", 1978, No. 6, p. 33).

However, the production of such sorbents is not cheap, and it is not practical to use them, for example, to extract small quantities of copper ions after chemical treatment of wastewater.

For such cases, the use of sorbents from production waste is promising. Waste tanned leather chips are a matrix of fibrous structure containing carboxyl and amine groups. This waste can be used, for example, to extract a small amount of some dyes from wastewater.

The objective of the invention is the creation of a sorbent of a fibrous structure based on waste leather tanned chips, with improved ability to extract a variety of components from different environments.

This task is achieved by a method for producing a sorbent of a fibrous structure based on tanned leather shavings waste, including treating the fibrous matrix with an aqueous solution of a polyelectrolyte obtained by alkaline hydrolysis of polyacrylonitrile or a copolymer based on it.

An aqueous solution of polyelectrolyte is obtained by alkaline hydrolysis of waste polyacrylonitrile (PAN) fibers, for example, waste knitted fabrics from 100% PAN fibers. PAN fibers (the trade name in Russia is “nitron”) are made from a copolymer of acrylonitrile (92%), methyl acrylate (6.3%) and itaconic acid (1.7%).

For alkaline hydrolysis, non-fibrous wastes of the acrylonitrile polymer or its copolymer with other monomers can also be used.

Example 1. A sample of 5.0 g of waste from a knit fabric of 100% nitron is placed in 100 ml of a solution of sodium hydroxide containing alkali 3.77 g, and heated at the boiling temperature with stirring until complete homogenization. The solution is cooled and acidified (for example, with 30% acetic acid) until the pH is slightly acidic (4.0-5.0). Symbol of the resulting solution of the PAK-0 polyelectrolyte.

The washed waste of the tanned leather shavings is poured with a hot (about 75 ° С) PAK-0 solution (with a hydrolyzed polymer content of 5-30% by weight of the shavings) with the bath module 30 and kept until room temperature is reached. The obtained fibrous sorbent is washed with water and used, for example, to extract iodine or copper ions from wastewater from aqueous solutions after their chemical treatment.

Example 2. A sample of 5.0 g of waste fiber nitron, as in example 1, is placed in a solution of sodium hydroxide with the addition of 10% hydrochloric acid hydroxyamine by weight of waste fiber. Then proceed, as in example 1. The conventional name of the resulting solution of the polyelectrolyte PAK-10.

Wastes of leather chips are treated with PAK-10 solution in the same way as chips are treated with PAK-0 solution in Example 1.

The comparative sorption characteristics of the initial unmodified leather tanned shavings and shavings modified with PAK-0 and PAK-10 polyelectrolyte solutions are presented below.

Used sorbent Sorption of iodine from an aqueous solution (sorbent in H ⁺ / Cl ^- form), mg / g Sorption of copper from model wastewater (sorbent in Na ⁺ / OH form), μg / g Original Leather Shavings 75 62 Modified shavings PAK-0 96 282 Modified shavings PAK-10 145 324

Thus, the obtained sorbents make it possible to very effectively extract molecular iodine and copper ions from aqueous solutions. The selection of appropriate conditions (temperature, pH of the medium, etc.) also allows the use of the obtained sorbents for the extraction of ions of other heavy metals, for example, cadmium, nickel, etc. from aqueous solutions.

Claims (2)

1. A method of producing a sorbent of a fibrous structure, comprising treating a fibrous matrix with an aqueous solution of a polyelectrolyte, characterized in that the fibrous matrix of leather tanning waste is treated with an aqueous slightly acidic solution with a pH of about 4.0-5.0 of a polyelectrolyte obtained by alkaline hydrolysis of polyacrylonitrile or a copolymer on it basis. 2. The method according to claim 1, characterized in that the polyelectrolyte is obtained by alkaline hydrolysis of polyacrylonitrile or a copolymer based on it in the presence of an additive of 1-10% hydroxylamine by weight of the polymer or copolymer.