The paper presents an analysis of the methods for the chemical modification of biochar. The characteristics of acid and basic modifications, modifications with hydrogen peroxide, sulfonation, amination, impregnation with metal oxides, and magnetization are examined. It is demonstrated that the method of modification, the parameters of the technological process, and the nature of the modifying agent all exert an influence on the chemical composition, structure, porosity, pore size, and total specific surface area of the modified coal. The combination of methods, technological parameters, and modifiers allows for the production of sorbents for wastewater treatment based on biochar with specific properties for the sorption of certain groups of different pollutants.

Keywords: biochar, chemical modification, sorption properties, porosity, pore size

The article is devoted to the use of natural minerals in water treatment. The paper presents the results of a study of the sorption properties of the opoka. The study showed the advantages of flask membranes compared to those deposited with silicic acid. The optimal conditions for the modification of the flask were determined, which make it possible to purify water from metal impurities to the required level.

Keywords: groundwater, water purification, deferrization, membrane, deposited membrane, sorption methods, flask, polyacrylamide