Studies on adsorptions of metallic ions in water by zirconium glyphosate (ZrGP): Behaviors and mechanisms

A new adsorbent named zirconium glyphosate [Zr(O3PCH2NHCH2COOH)2·0.5H2O, denoted as ZrGP] and its selective adsorptions to Pb2+, Cd2+, Mg2+ and Ca2+ ions in water were reported in this paper. Compared to other zirconium adsorbents, such as zirconium phosphate [Zr(HPO4)2], ZrGP exhibited highly selective adsorption to Pb2+ in solution which contained Pb2+, Cd2+, Mg2+ and Ca2+ ions. The loaded ZrGP with metallic ions can be efficaciously regenerated by aqueous solution of HCl (1.0 M) without any noticeable capacity loss, and almost all of it can be reused and recycled. The memory effect on structural regeneration of ZrGP was also found when Mg2+ and Ca2+ were adsorbed. To be specific, the structure of ZrGP was destroyed due to adsorbing these two ions, but it could be regenerated after the loaded materials were dipped in HCl solution (1.0 M) for several minutes to remove metallic ions.