High-hardness salt-containing water concentration method based on monovalent cationic selective electrodialysis

Abstract

The invention discloses a high-hardness salt-containing water concentration method based on monovalent cationic selective electrodialysis. The method comprises the following steps: 1, performing chemical precipitation hardness removal and pretreatment on raw water; 2, performing reverse osmosis desalination treatment; and 3, regulating the pH value of reverse osmosis concentrated saltwater with hydrochloric acid or sulfuric acid to be 4-6 so as to serve as raw electrodialysis water, and enabling the water to respectively enter a desalting chamber and a concentration chamber formed by an anode membrane and a cathode membrane at an interval in an electrodialysis membrane stack, thereby obtaining high-salt electrodialysis water and low-salt electrodialysis water. According to the method disclosed by the invention, extra equipment and devices are not needed, and two ions forming a scale forming matter are separated under the condition that the recovery rate is not changed, so that a scaling phenomenon caused by simultaneous interception or simultaneous permeation is avoided.

Description

technical field [0001] The technical solution of the invention relates to a high-hardness brine concentration process and system based on monovalent cation selective electrodialysis, which belongs to the field of wastewater treatment and environmental protection. Background technique [0002] The rapid development of social economy has driven the rapid development of enterprises, but the ensuing environmental problems, especially wastewater discharge, have become the bottleneck restricting the coordinated and sustainable development of economy, society and environment. Chemical, papermaking, printing and dyeing, leather and other industrial enterprises, on the one hand, because salt may be used as one of the raw materials in the process, on the other hand, the gradual concentration of salt in the process water makes the waste water have a high salt content. If it is not properly disposed of, it will inevitably Bring water and soil ecological environment pollution. Therefore...

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Problems solved by technology

[0005] The present invention aims at the current high-salt industrial wastewater concentration treatment requirements, and the problems of complex equipment and low recovery rate in the prior art, and proposes a high-hard salt-containing wastewater concentration process and system based on monovalent selective cation electrodialysis. The system With chemical dehardening, reverse osmosis, and electrodialysis as the core, chemical precipitation is used to remove hardness ions in the system; reverse osmosis is used to desalinate and initially concentrate low-concentration brine to produce high-quality desalinated water and obtain initially concentrated brine; Electrodialysis will concentrate the initially concentrated brine to obtain high-concentration brine. At the same time, the electrodialysis device is composed of a monovalent cation membrane and an ordinary anion membrane, which can effectively control the concentration of scaling ions in the concentrated brine.

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