Study of the natural mineral sorbents’ absorption properties of the Ural region (Russia)

Abstract

The article is devoted to the study of the sorption properties of natural mineral sorbents from deposits located in the Ural (Sverdlovsk, Kurgan, Chelyabinsk regions). For the experiments, the following natural sorbents were used: bentonite clays with an admixture of carbonate inclusion; flasks - dense, slightly porous rocks consisting of the smallest particles of biogenic silica; diatomite; glauconites- layered low-temperature ferruginous micas; calcined vermiculite. The absorption capacity in relation to heavy metals: copper, zinc, lead, cadmium, nickel, chromium, arsenic has been investigated. The are no significant differences in the completeness of sorption between the studied sorbents, all of them can be successfully used under certain conditions for ecological and geochemical recultivation of soils contaminated with HMs. Separately, the influence of sorbents on the copper and chromium absorption as the largest soil pollutants in the Urals was considered. Experiments have shown that copper in the form of a bivalent cation is well sorbed by all sorbents, while chromium in the form of a complex anion (in a hexavalent form) is practically not sorbed. To ensure a proper chromium sorption effect, it was decided to preliminary transfer it into a trivalent cationic form by a reducing agent, which was ferrous ammonium sulfate - FeSO4·(NH4)2·SO4·6H2O. The reduction of chromium to a trivalent cation increases the sorption completeness to 94-99%.