RU2524038C1 - Method of extracting silver ions from low-concentration silver nitrate solutions - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method includes passing the solution through polymer fibre for sorption of silver ions. After passing the solution, silver ions contained in the fibre are reduced to a metal state with 0.02 M aqueous solution of a mixture of ascorbic acid with glucose in ratio of 1:9. Silver metal is then extracted by burning the silver-containing fibre in an air atmosphere at temperature of 450-500°C, followed by washing the formed silver reguli.

EFFECT: recovering silver ions from industrial waste water, improved method of extracting silver from process solutions used when producing textile materials with antimicrobial properties.

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Description

The invention relates to a method for the separation of silver ions from low-concentration solutions, based on the sorption of silver ions by a polymer fiber containing thioamide groups, followed by reduction of silver ions to metal, and can be used in resource-saving technologies aimed at the isolation and regeneration of a scarce expensive component - silver ions from sewage of industrial productions.

A known method of extracting silver ions from low concentrated solutions of silver nitrate, including passing the solution through a polymer fiber (see, for example, US patent No. 3821137, C08b 23/00, publ. 06/28/1974).

The disadvantage of this method is the lack of conditions for the subsequent selection of sorbed silver, namely, the type of reagent of the reducing agent, the composition of the reducing system, its concentration, the hydromodule for processing a fiber containing silver ions, and the temporary conditions for the reduction of silver ions in the fiber phase, as well as the conditions of extraction are not given. metallic silver (temperature of burning a fiber containing metallic silver).

The basis of the invention is the task to improve the method of extraction of silver ions from low concentrated aqueous solutions of silver salts and to ensure the separation of silver from technological solutions used in the preparation of textile materials with antimicrobial properties.

The problem is solved in that in a method for extracting silver ions from low-concentrated solutions containing silver ions, including passing the solution through a polymer fiber, reducing the silver to a metallic state, a 0.02 M aqueous solution of a mixture of ascorbic acid and glucose is used in a ratio of 1: 9, and the metal is isolated silver is carried out by burning silver-containing fiber in an atmosphere of air at a temperature of 450-500 ° C, followed by washing the formed kings of silver.

Since silver is restored to a metallic state, a 0.02 M aqueous solution of a mixture of ascorbic acid with glucose is used at a ratio of 1: 9, and silver metal is released by burning silver-containing fiber in an atmosphere of air at a temperature of 450-500 ° C, followed by washing of the formed silver kings, silver from technological solutions used to obtain textile materials with antimicrobial properties.

The extraction of silver ions from low concentrated solutions of silver nitrate is as follows.

Example 1

50 g of chemisorption fiber containing thioamide groups in an amount of 2.8 mEq / g are placed in a column and a solution of silver nitrate with a concentration of 4.3 g / l is passed through it at room temperature at a solution transmission rate of 200 ml / h until a breakthrough occurs, which is judged by the silver content in the filtrate. The filtrate is analyzed for the content of silver ions according to the above procedure.

To restore silver ions contained in the fiber, the fiber is placed in a 0.02 M aqueous solution of a mixture of ascorbic acid and glucose at a ratio of 1: 9, a water module of 100 ml / g and kept at a temperature of 100 ° C for 120 minutes. At the end of the processing, the fiber is squeezed, washed and dried at a temperature of 100 ° C. Silver metal is isolated by burning fiber in a porcelain crucible in a muffle furnace in an atmosphere of air at a temperature of 450 ° C for 30 minutes. After washing, the kings of silver are weighed. The silver content is 290 mg.

Example 2

A solution containing 4 g / L silver nitrate, 0.15 g / L iron nitrate, 20 g / L copper nitrate, 0.0025 g / L zinc nitrate is passed at room temperature through a chemisorption fiber containing 2.5 mEq / g thioamide groups.

The filtrate composition (iron nitrate Fe (NO ₃ ) ₃ - 0.15 g / l, copper nitrate Cu (NO ₃ ) ₂ - 20 g / l, zinc nitrate Zn (NO ₃ ) ₂ - 0/0015 g / l) confirms the selectivity of extraction silver given chemisorption fiber under the conditions described above.

The reduction of silver ions contained in the fiber is carried out by placing the chemisorption fiber in a 0.02 M aqueous solution of a mixture of ascorbic acid and glucose at a ratio of 1: 9, a water module of 100 ml / g, and kept at a temperature of 90 ° C for 150 minutes. At the end of the processing, the fiber is squeezed, washed and dried at a temperature of 100 ° C. Silver metal is isolated by burning fiber in a porcelain crucible of a muffle furnace in an atmosphere of air at a temperature of 500 ° C for 20 minutes. After washing, the kings of silver are weighed. The silver content is 250 mg.

The technical control of the process of extracting silver from spent technological solutions is carried out titrimetrically, for which 1 ml of an alum iron solution (concentration 40 g / l) is added to 5 ml of the filtrate and titrated with constant stirring with 0.1 M potassium radonide KSCN until a yellow color appears. The calculation of the degree of extraction of silver ions (R) is carried out according to the formula:

, $$R=\mathrm{one\; hundred}-\frac{\left({\nu }_{\mathrm{one}}-{\nu }_2\right)\cdot 1080}{{\nu }_{\mathrm{one}}},\%$$

,

where ν ₁ is the amount of KSCN solution, which went to the titration of the working sample of the technological solution, ml;

ν ₂ - the amount of KSCN solution, which went to the titration of a working sample of the filtrate, ml

Claims (1)

A method of extracting silver ions from low concentrated silver nitrate solutions, comprising passing a solution through a polymer fiber to adsorb silver ions, characterized in that after passing the solution, silver ions contained in the fiber are reduced to a metallic state with a 0.02 M aqueous solution of a mixture of ascorbic acid and glucose at a ratio of 1: 9, and metallic silver is isolated by burning silver-containing fiber in an atmosphere of air at a temperature of 450-500 ° C, followed by washing to form king kings of metallic silver.