Research on the co-adsorption of As(V) and Cd(II) by Mg/Al/Fe-CLDH

Abstract

Abstract Arsenic and cadmium are often co-existing in non-ferrous smelting wastewater, and the physicochemical properties such as surface charge, ionic morphology and redox activity are different between arsenic and cadmium, making the simultaneous removal of arsenic and cadmium challenging. In this study, an efficient and stable composite material of Fe modified Mg/Al-LDH was used for arsenic and cadmium co-adsorption experiments. The following conclusions were drawn: As (V) and Cd(II) were inserted into the interlayer region of the hydrotalcite, which As(V) was more favorably exchanged into the interlayer, as the inserted Cd(II) combined with the interlayer CO32− to generate a precipitate; The negatively charged As(V) served as a shield to balance the electric forces between Cd(II), and the coordinated deprotonated As(V) acted as an anionic bridge to enhance the adsorption of Cd(II). The structure-activity relationship between material structure and synchronous removal of arsenic and cadmium was clarified, and the mechanism of synchronous removal was revealed, which provided technical guidance for synchronous removal of arsenic and cadmium from non-ferrous metal smelting wastewater.