Effective defluoridation of water using nanosized UiO-66-NH 2 encapsulated within macroreticular polystyrene anion exchanger

Environmental concerns associated with the efficient defluoridation of contaminated water remain a substantial challenge. In this work, a new nanocomposite, UiO-66-NH @PS , was successfully fabricated via in situ precipitation of a water-stable metal-organic framework (UiO-66-NH ) inside a commercial polystyrene anion exchanger PS . The as-formed nanocomposite UiO-66-NH @PS was characterized using various morphological methods, which demonstrated that nanosized UiO-66-NH was homogenously dispersed within the inner pores of PS . Batch adsorption experiments indicated that UiO-66-NH @PS exhibited outstanding adsorption performance for fluoride over a broad pH range of 3.0-8.0. The saturated adsorption capacity of fluoride at 298 K was 27.5 and 32.8 mg/g for pH 6.5 and 4.5 with the adsorbent dosage of 0.5 g/L and initial concentration of 5-80 mg/L. Moreover, the utilization rate of active adsorption sites of UiO-66-NH was greatly improved after encapsulation. The XPS study indicated that the integrated effects of specific inner-sphere coordination and ligand exchange between fluoride and UiO-66-NH might be the dominant adsorption mechanism. Fixed-bed tests indicated that the UiO-66-NH @PS column could successively produce clean water with bed volumes of 350 and 70 ([F ]