SU1535603A1 - Method of extracting ions of transition metals from aqueous solutions - Google Patents

Abstract

This invention relates to the recovery of transition metals from aqueous solutions and wastewater using membrane methods. The aim of the invention is to increase the productivity and reduce the costs of the binding agent. The essence of the method is the binding of recoverable transition metal ions into a ternary polymer-metal complex polyacrylic acid-metal ion-polyethyleneimine at a molar ratio of N = [PEI] / [PAA] = 0.2-0.8 and subsequent ultrafiltration of the resulting mixture through a membrane average pore diameter of 500 ± 50 A °. 1 tab.

Description

The invention relates to a method for extracting metals from aqueous solutions and wastewater by membrane methods and can be used in non-ferrous metallurgy, electroforming, in the chemical industry, and. also in other areas of the national household for wastewater treatment and the creation of drainless technological schemes.

The purpose of the invention is to reduce the costs of the binding agent and increase the productivity of ultrafiltration membranes.

The goal is achieved by the proposed method of extracting metal suits by using semipermeable membranes. Transition metal ions, such as cadmium, are bonded to a ternary low energy-metal complex (TPG) by adding

into a solution ,, a common Cd ions

,

you are a tetan-- tia. cross-molecular-molecular (M 7-106} polyacrylic acid (PAA) and high molecular weight () polyethylenimine (PEI) at a molar ratio of n 0, ..., 8, followed by ultrafiltration through a membrane.

TPMK - polyacrylic acid - Cd2 + - polyethylenimine is formed due to the ionic interaction between the carboxyl groups of PAA and Cd1 ions and the coordination binding of ions with the imine groups of PEI.

PRI me R. To 180 ml of a 5.55 CdSO aqueous solution was added a 0.3 m (2.16%) solution of polyacrylic acid PAA () and a 0.06 m (0.26%) solution of PEI (104) with the expectation that the molar ratio was / s PEI

(L

with

cn

with

SP

se

about

WITH

you 0, 8.

 PAK 0,2; 0.4; 0.6;

Total volume 200 ml. After adjusting the pH to 960, these solutions are separated through an ultrafiltration membrane. The results obtained at atm are presented in the table.

The capacity of the ternary polymer-metal complex (TPMK) for transition metals is 3-5 times larger than the capacity of individual polymer complexing agents.

An advantage of the proposed method in comparison with the known method is the use of membranes with an average pore diameter of 500 A for ultrafiltration at a relatively low working pressure, which makes it possible, together with a high degree of extraction of metal ions, to significantly increase the productivity of the process.

The advantage of the proposed method is also the possibility of multiple use of complex

five

five

0

PAC and PAYLER, which is achieved by the destruction of the complex at a pH less than 2.0 and at a pH greater than 11.0. This allows the metal ion extraction process to be carried out in a closed, waste-free mode.

Claims (1)

Invention Formula A method of extracting transition metal ions from aqueous solutions, including the introduction of a water-soluble polymeric binding agent into the solution, the formation of polymer-metal complexes and ultrafiltration separation of the resulting mixture, characterized in that, in order to reduce the costs of the binding agent and improve the performance of ultrafiltration membranes, a binding agent, a mixture of polyethylenimine and polyacrylic acid is used at a molar ratio of 0.2-0.8.