Effect of inorganic and organic ligands on the sorption/desorption of arsenate on/from Al-Mg and Fe-Mg layered double hydroxides

► More arsenate than phosphate was sorbed onto Fe-Mg-LDH, while more phosphate than arsenate was sorbed onto Al-Mg-LDH. ► Each ligand has showed different capacities to inhibit the fixation of arsenate on LDH surfaces. ► Arsenate sorption decreased with increasing pH and ligand concentration. ► The longer the AsO4 residence time on LDH surfaces the less effective the competing ligands were in desorbing AsO4. ► A greater percentage of the arsenate was removed by phosphate from Al-Mg-LDH than from Fe-Mg-LDH.