Adsorption of Pb(II) and Cd(II) from aqueous solutions on polyvinylpyrrolidone modified Kyzylsok natural clay

Abstract

The present work considers the production of a cheap and effective sorbent based on natural clay from the Kyzylsok deposit (Almaty region) in order to purify wastewater from heavy metal ions (Cd²⁺, Pb²⁺). It was found that the starting material is applicable for the extraction of Cd²⁺ ions (the degree of extraction is (97.00 ± 1.99) %), while for the extraction of Pb²⁺ ions the initial clay must be modified. The modification was carried out using polyvinylpyrrolidone (PVP). The degree of extraction of Pb²⁺ ions with modified clay increased from (70.00 ± 1.77)% to (98 ± 1.13)% The influence of PVP concentration in the composite material (modified clay) on its sorption properties was studied: the optimal concentration of PVP was 0.1 % solution. The desorption of metal ions was also investigated in the work, it does not exceed 2%. It was found that the sorption process is described by the monomolecular Langmuir isotherm model and the kinetic model of the pseudo-second order.