Selective removal of methyl orange and Cr anionic contaminants from mixed wastewater by in-situ formation of Zn-Al layered double hydroxides

摘要

A one-pot method to remove methyl orange (MO, organic contaminant) and CrO42- (Cr, inorganic contaminant) from waste water was developed by forming Zn-Al layered double hydroxides (ZnAl-LDH). By this process, the efficiency of MO or Cr removal was nearly 100% and reached the theoretical maximum of ZnAl-LDH removal capacity. In addition, the mixed contaminants of MO and Cr in wastewater can be separated from each other by controlling the addition of Zn/Al solution using this one-pot method. The molecular arrangement of the immobilized contaminants in the interlayer of LDH and the selective removal mechanism were analyzed by calculated binding energies obtained from molecular simulation.