Removal of Heavy Metal Ions, Pb2+ and Cd2+, from Water by Use of Lanthanide-Coordination Polymer as Sorbent.

The removal of Cd2+ and Pb2+ from water under room conditions was done by employing Ce (III), [Ce2(μ3‐atp)2(μ2‐atp)(H2O)8].4H2O (1) (atp=2‐aminoterephthalate) as a sorbent. Lanthanide-coordination polymer 1 is a new two‐dimensional coordination polymer synthesized by solvent diffusion approach. This was characterized by X‐ray single crystal diffraction, powder X‐ray diffraction (PXRD), Fourier transformation infrared (FT‐IR)spectroscopy and thermal analysis (TGA). After the adsorption the amount of metal ions in water was determined by atomic absorption spectroscopy and the removal efficiency was calculated. The effect of contact time on the adsorption of single solutions of these heavy metal ions at optical pH 7 shown that maximum removal efficiencies was achieved within 30 min with 94% and 87% of Pb2+ and Cd2+ respectively. To evaluate the competitive adsorption properties of the coordination polymer, it was introduced into a solution containing equal amounts of binary metal ions Ni2+, Mg2+, Ca2+ and Fe3+ with Cd2+ or Pb2+. The results show that polymer 1 uptake Cd2+ and Pb2+ from the solution with high selectively. About 90% of both Cd2+ and Pb2+ were removed from water after half an hour. The result of desorption of the metal ions from the sorbent showed that 96.5% of the metal ions desorbed from the sorbent. The reusability of the recovered sorbent show that the sorbent could be simply recovered, then reused without observable loss in the removal efficiency and with structural stability.