Porous metal-organic frameworks adsorbents as a potential platform for defluoridation of water

Fluoride contamination in drinking water has been classified as one of the major concerns worldwide. In this work, we report a number of novel type of Fe-based porous metal-organic frameworks (MOFs), particularly that based on iron coordinated with fumaric acid (MIL-88A), for the adsorptive removal of fluoride from water. MIL-88A adsorbent were tested for adsorption capacity and uptake time at different concentrations. Significantly, the as-prepared flexible porous MIL-88A exhibits much higher defluoridation efficiency than that of other Fe-based MOFs. The maximum fluoride uptake capacity for MIL-88A was calculated to be 40.42 mg g(-1) at the room temperature. Furthermore, there were no significant influence on fluoride removal by MIL-88A in the presence of coexisting anions (chloride, nitrate, bicarbonate, sulfate and phosphate), suggesting MIL-88A had a high selectivity for fluoride. Moreover, adsorption of fluoride at different temperatures showed that the adsorption was a spontaneous and endothermic reactions. This work demonstrates that Fe-based MOFs adsorbents hold great promises in the application of the selective fluoride removal from water .