Method for recycling copper-containing wastewater from micro-etching

A method for recycling a copper-containing wastewater from a micro-etching, comprising adding a FeS-based pH-responsive material to a weakly-acidic copper-containing wastewater from the micro-etching, to allow a reaction I to obtain a precipitate with CuS as a main component, wherein

• the FeS-based pH-responsive material is prepared through the following process:
• slowly adding a sulfide salt solution to a mixed solution comprising a modified crosslinking agent, a stabilizing and dispersing agent, and a ferrous salt, to allow a heterogeneous precipitation reaction to obtain the FeS-based pH-responsive material;
• wherein the modified crosslinking agent is obtained through a crosslinking reaction of a monomer comprising both carboxyl and sulfhydryl with a crosslinking agent;
• the reaction I is conducted at a pH value of 3.95 to 6.05 for 10 min to 25 min;
• a Cu2+/S2− molar ratio of the copper-containing wastewater from the micro-etching to the FeS-based pH-responsive material is 1:(1.0-1.25);
• the monomer comprising both the carboxyl and the sulfhydryl comprises at least one of mercaptopropionic acid, mercaptoacetic acid, and mercaptoacrylic acid;
• the crosslinking agent is nanoscale silica;
• and
• a molar ratio of the monomer comprising both the carboxyl and the sulfhydryl to the crosslinking agent is (1.0-1.6):1.