Facile synthesis of NH2-UiO-66 modified low-cost loofah sponge for the adsorption of fluoride from water

Leaching of fluoride in drinking water can lead to fluorosis. It is a good method to reduce the concentration of fluoride ion in drinking water by selecting the adsorption material with large adsorption capacity and good selectivity. Herein, the NH2-UiO-66 based loofah sponge modified porous composite was prepared. The composite material took loofah sponge (LS) as the carrier, and loaded NH2-UiO-66 on the surface of LS by in-situ growth method. The structure of the prepared NH2-UiO-66 @LS was investigated by PXRD, FTIR, SEM, and XPS. The influencing factors of different materials, contact time, adsorbent dosage, preliminary fluoride concentration, and co-existing anions were optimized. Compared with LS, the adsorption efficiency of NH2-UiO-66 @LS was greatly improved, and the adsorption capacity was 65.08 mg/g for fluoride ion. Moreover, the maximum removal efficiency of NH2-UiO-66 @LS was the initial fluoride concentration of 100 mg/L. Under the condition of the coexistence of other anions, the composite material has a specific adsorption performance for fluoride within 40 min. Furthermore, the data of fluoride adsorption was best fitted with pseudo-second-order kinetic model. The thermodynamic studies showed that the fluoride adsorption process on NH2-UiO-66 @LS was feasible, spontaneous and endothermic. In addition, synthesized NH2-UiO-66 @LS can be reused upto eight cycles. The plausible fluoride adsorption mechanism of NH2-UiO-66 @LS was majorly ruled by electrostatic attraction and complexation. Furthermore, the raw material is easy to obtain and the preparation process of NH2-UiO-66 @LS is simple. Hence, the large adsorption capacity of NH2-UiO-66 @LS compared with reported adsorbents for fluoride makes it have potential application prospect from wastewater on industrial scale. •NH2-UiO-66 @LS, a new material that was obtained by in-situ growth method for defluorination.•The adsorption capacity of NH2-UiO-66 @LS was 65.08 mg/g for fluoride ion, which was higher than LS.•The fluoride adsorption ability of NH2-UiO-66 @LS maintained good selectivity from actual wastewater.•The reusability study indicated NH2-UiO-66 @LS was regenerable upto eight cycles and kept in stable structure.•NH2-UiO-66 @LS is very low-cost, easy to synthesize, and environmentally friendly.