Simultaneous removal of hexavalent chromium and tetracycline from simulated wastewater by FexSy impregnated hydrogel

Hexavalent chromium (Cr(VI)) and tetracycline (TC) have become widely distributed pollutants, and their combined pollution has attracted widespread attention from researchers. In this study, FexSy particles impregnated hydrogels were prepared to simultaneously remove Cr(VI) and TC from simulated wastewater. The effects of the initial concentration of pollutants, pH value, and coexisting dissolved organic matter on the removal rate of pollutants in single pollutant systems and dual pollutant systems were investigated in detail. In single pollutant systems, Cr(VI) was mainly reduced to Cr(III) by Fe(II) and S(-II), and then separated from the solution by complexation or precipitation. And TC firstly formed the Fe (II)-TC complex with Fe (II), which was subsequently oxidized to form Fe(III)-TC complex and generated O2 & sdot;-, leading to the degradation of TC. S(-II) mainly played a role in reducing Fe (III), promoting the circulation between Fe(II) and Fe(III). The co-removal mechanism of Cr (VI) and TC was further understood in dual pollutant systems. The degradation pathway of TC was proposed through HPLC-MS analysis. Overall, our work provided economical and effective materials for simultaneously removing Cr(VI) and TC from simulated wastewater.