*WINNER* Heavy metal remediation from aqueous solutions by new silica-immobilized thiosemicarbazone materials

Abstract

Heavy metals enter the water supply through both natural and industrial processes. While some of these metals are necessary for human metabolism, many are toxic even in small concentrations. Various methods such as ion-exchange chromatography, reverse osmosis, and chemical precipitation are currently employed to remove heavy metals from water, however the high costs and large waste generation associated with these have led to research in new methods of heavy metal remediation. This work focused on the metal ion extracting capabilities of new silica-immobilized-thiosemicarbazone (SIT) materials. These materials were synthesized by introducing a covalent linkage between various thiosemicarbazide compounds and a functionalized silica particle, resulting in five new immobilized thiosemicarbazone ligands. The extraction efficiency of each of the five materials was then evaluated by analyzing the uptake of two radioisotopes, Cd-109 and Ni-63, across a wide range of pH levels. Overall, the compounds displayed an increased affinity for Cd-109 with an increase in pH, however, Ni-63 extraction was limited. Successful extraction of heavy metals by these newly produced SIT materials could lead to more efficient remediation of toxic substances in water.