Siberian Federal University

Hollow aluminosilicate microspheres (cenospheres) of stabilized composition (glass phase – 95.4 wt.%; (SiO2/Al2O3) glass – 3.1), isolated from fly ashes from coal combustion, were used for preparation of composite sorbents containing sorption-active component based on zirconosilicates of framework structure. The synthesis products were characterized by XRD, SEM-EDS and low-temperature nitrogen adsorption methods, and their sorption properties towards Pb2+ and Cd2+ were studied. The zirconosilicate material shows high distribution coefficient in the process of sorption of Pb2+ and Cd2+ from aqueous solutions (~ 105–106 ml/g). It has been shown that Pb2+-exchange form of zirconosilicate material undergo a phase transformation as a result of thermal exposure at 1000 oC to form phases of orthorhombic lead zirconate PbZrO3, trigonal parakeldyshite Na2ZrSi2O7 and tetragonal zircon ZrSiO4