REPEATED WASTE OF HUMATIVES INTO PLAIN METALS IN THE PURIFICATION OF WEAKLY ACID WATER, TO CLEAN Cu2+, Pb2+

Destroyed military and industrial facilities have grave consequences not only for the country's economy, but also for the environment and natural resources. At present, humic acids are quite well known and have been sufficiently studied by the natural sorbent. Due to a wide range of functional groups, they perform accumulative, transport, regulatory, protective and physiological functions. The interaction of metal ions with humates does not have a single clear described mechanism. This is facilitated by the complexity and diversity of the structure of humic acids, as well as various reaction conditions in laboratory and natural conditions. Therefore, ways to increase the efficiency of sorption, improve and search for new properties of these substances still remain relevant. In this work, the possibilities of reverse bonding of copper and lead ions in slightly acidic aqueous solutions at pH values of 4,4–6,3 are shown. Humic acids were isolated from peat and brown coal, and potassium humates produced in China were also used. In this study, model solutions of copper (II) sulfate and lead (II) acetate were used with a calculated concentration in terms of copper and lead of about 400 and 1000 mg/dm3, respectively. The regeneration of metal humate complexes was carried out by lowering the pH of the medium to 2,1–2,2. The degree of lead sorption was 97–99 % for Pb2+ solutions with a concentration of 216 mg/dm3. Studies have shown the effectiveness of re-use of regenerated humates with a degree of metal release of 85–91 % in relation to the sorbed amount. The metal content in the experiment was determined by inductively coupled plasma atomic spectroscopy. It was also found that the ratio of the average values of the specific sorption of lead and copper was from 2,8 to 3,1 for various types of humic acids (humates). The proximity of these values with respect to the atomic masses of lead and copper (3,3), in the author's opinion, is associated with the interaction of copper and lead ions with humates in a stoichiometric ratio due to a chemical reaction (reactions). The sorption given in the experiment is described by a linear dependence in the coordinate system: the mass of the sorbed metal (ions) – the mass of humates.