Siberian Federal University

Acid-base centers on the sulfonated coal surface have been studied with Hammett method using indicators of acid orange, acid blue anthraquinone and methylene blue. It has been established that sulfonated coal is a medium- acid sorbent of cations, which works effectively in the pH 4–10 range, which corresponds to all types of natural and industrial waters containing heavy metal cations. Elemental analysis of the resulting sulfonated coal showed the presence of sulfogroups on the surface in an amount of 3–4 %, which is sufficient for a monolayer uniform modification of the sorbent surface. The resulting sorbent is characterized by a specific micropore surface of 171 m 2/g and a micropore volume of 0.062 cm3/g with dimensions of 0.8–2.0 nm, which corresponds to the majority for modified coals. The maximum sorption capacity of sulfonated coal on Cu (II) is 0.23 mg/g, compared with the sorption capacity of the source carbon material of 0.02 mg/g in a neutral medium