Investigations on post-synthetically modified UiO-66-NH 2 for the adsorptive removal of heavy metal ions from aqueous solution

Abstract The metal organic framework UiO-66-NH 2 has been post-synthetically modified to introduce thiourea, isothiocyanate and isocyanate functionalities without compromising the structural and thermal stability of the parent framework. 1 H NMR and IR spectroscopies have been used to monitor the extent of framework functionalization. UiO-66, UiO-66-NH 2 and the new functionalized frameworks UiO-66-NHC(S)NHMe, UiO-66-NHC(S)NHPh, UiO-66-NCS and UiO-66-NCO have been studied as adsorbents for the capture of a range of heavy metals from homoionic aqueous solution, with a view towards applications in environmental remediation. Functionalization markedly improved metal removal efficiency up to 99% with calculated maximum adsorption capacities of 49, 117, 232 and 769 mg/g for Cd 2+ , Cr 3+ , Pb 2+ and Hg 2+ respectively for UiO-66-NHC(S)NHMe.