Highly efficient and rapid removal of non-steroidal anti-inflammatory drugs from environmental samples based on an eco-friendly ZIF-67-molecularly imprinted composite

Non-steroidal anti-inflammatory drugs (NSAIDs) are emerging micropollutants, whose efficient removal from environmental samples has received widespread concern. In this study, an eco-friendly adsorbent based on a zeolitic imidazolate framework-molecularly imprinted composite (ZIF-67-MIP) was prepared in water and applied for the simultaneous removal of three NSAIDs containing diclofenac sodium, flunixin meglumine, and nimesulide. Characterization of the as-prepared ZIF-67-MIP was carried out via SEM, EDX, TEM, FTIR, XPS, TGA and zeta potential analysis. The Liu isotherm model was better fitter than other models for three NSAIDs, with the maximum adsorption capacities of 88.70 mg g-1 for diclofenac sodium, 79.78 mg g-1 for flunixin meglumine and 19.24 mg g-1 for nimesulide. Thermodynamic studies exhibited that the adsorption processes were spontaneous and endothermic. ZIF-67-MIP achieved rapid adsorption of three NSAIDs drugs, and the pseudo-secondorder model was better fitted for the adsorption processes of diclofenac sodium and flunixin meglumine, whereas the Elovich model was better fitted for that of nimesulide. Furthermore, ZIF-67-MIP had high selectivity, and showed great performance in the removal of three NSAIDs from 11 environmental samples and regeneration studies. Therefore, the developed ZIF-67-MIP is a promising and eco-friendly adsorbent for the fast and efficient removal of NSAIDs from the environment.