Mechanisms and novel performance of ZrO2/Fe3O4 composite for phosphate recovery from wastewater

Abstract

In this study, a composite material of Fe3O4 with excellent physical adsorption and ZrO2 with excellent chemical adsorption properties was synthesized to maximize the phosphate recovery efficiency in water. Fe3O4, ZrO2, and Fe3O4/ZrO2 were prepared using co-precipitation and characterized using various surface and structural analysis techniques. Fe3O4 exhibited both physical and chemical adsorption mechanisms, as evidenced by its pseudo-first- and pseudo-second-order kinetics during the adsorption/desorption process, while the dominant adsorption mechanism for ZrO2 was chemical adsorption. The adsorption mechanism of Fe3O4/ZrO2 shows physical adsorption by electrostatic attraction followed by chemical adsorption in which potential bidentate inter-complex and monodentate are formed. From the hydroxyl group analysis, it can be seen that the hydroxyl radicals increased by about 3.5 times or more due to the presence of Fe3O4 on the surface of ZrO2. Overall, the synthesis of Fe3O4/ZrO2 successfully improved the low adsorption performance of Fe3O4 while ameliorating the disadvantages of ZrO2.