Apparatus for producing acidic aqueous solution and method for producing acidic aqueous solution

A method for producing an acidic aqueous solution to produce the acidic aqueous solution from wastewater containing chloride ions and alkali metal ions, comprising:

• an electrodialysis process in which the wastewater is separated, by using an electrodialyzer including a cation-exchange membrane and an anion-exchange membrane, into electrodialysis concentrated water and electrodialysis diluted water by an electrodialysis treatment;
• an electrolysis process in which the electrodialysis concentrated water is electrolyzed to produce an acidic aqueous solution;
• a first circulating process in which at least some of the acidic aqueous solution is circulated to the wastewater supplied in the electrodialysis process;
• and
• a second circulating process in which at least some of the acidic aqueous solution is used in the electrolysis process,
• wherein the cation-exchange membrane is a m-phenolsulfonic acid-phenolic resin or a resin obtained by subjecting a styrene-divinylbenzene copolymer to a sulfonation reaction, and
• wherein a cationic polymer electrolyte containing a polyethyleneimine is formed on a surface of the cation-exchange membrane, and
• the anion-exchange membrane is an m-phenylenediamine-phenolic condensed resin, or a resin obtained by subjecting a styrene-divinylbenzene copolymer to an amination reaction.