Water Purification of Manganese Compounds by the Method of Catalytic Oxidation on Modified Pyrolusite

Manganese compounds have a toxic effect on the human body. Therefore, its content in drinking water should not exceed 0.05–0.1 mg/L, according to the hygienic standards of most countries. The concentration of manganese ions in some underground waters is 0.5–2 mg/L and can reach 6–10 mg/L in some cases. A method for the purification of drinking water from manganese by catalytic oxidation on modified pyrolusite is developed in this study. For this, the particles of crushed natural mineral pyrolusite are coated with a layer of inorganic and organic polymers (polysilicic acid and polymethyl methacrylate), which makes it possible to obtain dispersed particles with high structural stability in an aqueous medium. The filtering characteristics of modified pyrolusite with respect to soluble manganese compounds that are contained in aqueous solutions are evaluated. It is established the protective coating increases the structural stability of crushed pyrolusite and makes it possible to increase the specific volume of water purified from Mn 2+ to maximum permissible concentration levels without reducing the pressure loss on the filter and to increase the value of the sorption capacity of the filter material with respect to Mn 2+ . The filtering material made of modified pyrolusite allows one to additionally purify tap water from colored organic substances present in it (estimated by the optical density of water), simultaneously with manganese.