Super-stable mineralization of arsenic contaminated water using industrialized layered double hydroxides and derivatives

The issue of arsenic contamination, specifically in the form of As(III), is progressively escalating, so presenting a substantial danger to human well-being and security. In this study, commercially industrially produced CaAl-layered double hydroxides (CaAl-LDH) and MgAl-LDH were processed by calcination to produce a series of LDH-based mixed metal oxides (CaAl-x, MgAl-x) at calcination temperatures (x) ranging from 200 to 1000 °C. The resulting CaAl-900 exhibited a remarkable capacity for removing high concentrations of As(III), with a removal capacity of 612.5 mg/g. Besides, MgAl-500 demonstrated effective removal of low levels of As(III) to meet industrial emission standards, specifically below 0.5 mg/L. Furthermore, MgAl-500 was employed to simultaneously stabilize mixed toxic metals (As(III), Pb(II), and Cd(II) ions) in the treatment process of contaminated water, meeting standard levels. The comprehensive analysis of the characterization data indicated that the key determinant for the remarkable capacity of CaAl-900 to remove As(III) was its surface adsorption and memory effect. MgAl-500 also formed complex compounds through formation of As-O-Mg bond. This research showcases the capacity of LDHs produced from the industry for efficient remediation of As(III) ions in water.