METHOD FOR ELECTROCHEMICAL DISPOSAL OF WASTE WATER Russian patent published in 2023 - IPC C02F1/461 C02F1/44 

FIELD: wastewater treatment.

SUBSTANCE: electrochemical processing of wastewater from the production of polysulfide polymers (thiokols). The method includes mixing alkaline waste and dilute acid to obtain an aqueous solution with a pH of 9.7-10.0, settling the mixed aqueous solution until a two-phase dispersed system is formed with precipitation of a suspension of a low molecular weight polymer. The suspension is separated from the aqueous saline solution. The remaining aqueous saline solution is subjected to processing, the resulting mixture of salts is separated into the target products. Acid waste with a pH of 3.5-4.0, obtained after separating the coagulated precipitate of the polysulfide oligomer at the stage of coagulation with dilute acid of the polysulfide split dispersion, is subjected to treatment. Separate the resulting mixture of salts into the target products. Aqueous salt solution and acidic effluent are subjected separately from each other to electrochemical treatment in two-chamber membrane electrolyzers with cation-exchange membranes at an anode current density of 5-10 A/dm² and a volume current density of 12-16 A/l, using graphite anode and cathode with constant circulation of anolyte and catholyte. As the target product in the electrolysis of an aqueous saline solution, sodium tetrasulfide is obtained in the cathode chamber and sulfur in the anode chamber. The sulfur dioxide released during the electrolysis of the acidic waste is absorbed by demineralized water to form an acidic sulfur dioxide solution.

EFFECT: increased environmental safety of production due to the possibility of obtaining a sodium tetrasulfide solution uncontaminated with salts and organic impurities, the possibility of obtaining an aqueous solution of an acidic and recyclable reagent for coagulation of a residual low molecular weight dispersion from a split polysulfide dispersion with the transfer of a mercaptide group to a mercaptan group.

4 cl, 1 dwg