METHOD FOR ELECTRODIALYSIS WATER DESALIZATION Russian patent published in 2022 - IPC C02F1/469 B01D61/44 

FIELD: electrodialysis desalination.

SUBSTANCE: invention relates to a method for electrodialysis desalination of salt water, including the use of a package of alternating cation and anion exchange membranes located between the anode and cathode electrodes, with the formation of intermembrane chambers, as well as anode and cathode near-electrode chambers between the anode and cathode electrodes, respectively, and the ion exchange membranes closest to them , supplying electrical voltage to the anode and cathode electrodes, passing the water to be desalinated through the intermembrane chambers, combining the flows that have passed through the intermembrane chambers, in which the cation-exchange membrane is located on the side facing the cathode electrode to obtain a product in the form of a stream of desalinated water, combining the flows that have passed through the remaining intermembrane chambers to obtain a brine, simultaneously washing both near-electrode chambers by passing a washing solution of sodium sulfate through them, separating from gases passing through the near-electrode chambers of the washing solution, formed on the electrodes, using gas separators. The method is characterized by the fact that a package of alternating cationic and anionic ion-exchange membranes is used, in which the first and last membranes are cationic, with the said washing of the near-electrode chambers, a washing solution is used with an initial concentration of sodium sulfate not lower than the value of the total concentration of salts in the water to be desalinated, and this washing is carried out cyclically using two pairs of containers, using in each cycle consisting of two cycles, during the first cycle, the first tanks of the first and second pairs for supplying the washing solution from them, respectively, to the cathode and anode near-electrode chambers, and the second containers of the first and second pairs are used to collect the washing solution that has passed through the anode and cathode near-electrode chambers, respectively, after gas has been separated from it, and exchanging functions between the first and second containers in each pair in the second cycle of each cycle to use them for supplying or collection of wash solution.

EFFECT: use of the proposed method makes it possible to eliminate the shunting effect of washing near-electrode chambers with a corresponding reduction in unproductive energy costs and at the same time increase the efficiency of washing. In addition, with the implementation of the present invention, the loss of sulfate ions from the washing solution and the penetration of chloride ions into it with the release of chlorine at the anode can be prevented.

4 cl, 2 dwg, 2 tbl