Relevance. Nowadays water treatment technologies are universal. They consist of modules, the sequence of which may vary in the treatment scheme. It depends on the source of water supply and the purposes of treatment. The sorption purification stage is used in technology very oftеn. Sorption is used as the main stage of water treatment for treating wastewater. Also it is used as a post-treatment stage to obtain drinking water from natural sources. Stability of operation at different water temperatures, low cost, mechanical strength, possibility of regenerating sorbents and ease of use make the problem of modifying existing sorbents urgent to increase their selectivity and sorption capacity. Aim. To investigate the adsorption mechanism and sorption capabilities of the sorbent obtained by modifying AlOOH with silver ions in relation to inorganic ions and organic substances. Methods. X-ray phase analysis, method of thermal desorption of nitrogen, photocolorimetry, transmission electron microscopy. Results and conclusions. The sorbent was obtained by modifying aluminum oxyhydroxide with silver ions in a solution of silver nitrate with a silver ion concentration of 0.22 wt %. The physicochemical properties of the resulting sorbent were studied by X-ray phase analysis, transmission electron microscopy and the method of thermal desorption of nitrogen. The authors have determined phase composition and specific surface area as well as sorption kinetic parameters. They obtained sorption isotherms of inorganic ions and organic substances on aluminum oxyhydroxide modified with silver ions. Sorption isotherms were processed in Langmuir and Freundlich coordinates. The study showed that the resulting sorbent can be used in groundwater treatment technologies characterized by increased concentrations of organic substances.