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

Abstract

Present work considers the production of a cheap and effective sorbent based on natural clay originated from the Kyzylsok deposit (Almaty region, Kazakhstan) to purify wastewater from heavy metal ions (Cd 2+ , Pb 2+ ). It was found that the starting clay sample is applicable for the extraction of Cd 2+ ions (the degree of extraction is (97.40 ± 1.99) %), while for the extraction of Pb 2+ ions the initial clay must be modified by impregnation with 0.1 % polyvinylpyrrolidone (PVP) aqueous solution. The degree of extraction of Pb2+ ions with modified clay increased from (70.01 ± 1.77)% to (98.03 ± 1.13)%. The desorption of metal ions which was also investigated in the work did not exceed 2% confirming the usability of untreated and modified clay as sorbents for a long time. It was found that the sorption process is described by the monomolecular Langmuir isotherm model and the kinetic model of the pseudo-second-order.