Bifunctionalized Microspheres via Pickering Emulsion Polymerization for Removal of Diclofenac from Aqueous Solution

The removal of water pollutants with high selectivity and efficiency is still a huge challenge owing to the complex composition of contaminated water. The preparation, modification of Pickering emulsion microspheres, and their application in the adsorption and removal of non-steroidal anti-inflammatory drugs (diclofenac) in water were studied. Poly(2-(diethylamino)ethyl methacrylate-divinylbenzene), (P(DEAEMA-DVB)) microspheres were prepared by Pickering emulsion polymerization. The P(DEAEMA-DVB) polymer was modified with glycidyl trimethylammonium chloride (GTAC) and phenyl glycidyl ether (PGE) to prepare the adsorbent poly(quaternized and phenyl-functionalized) (P(QP-DVB)) with a substantial quantity of quaternary ammonium functional groups. The non-steroidal anti-inflammatory drugs in aqueous solution was mainly adsorbed by the anion exchange interaction with quaternary ammonium species. The adsorption kinetics coincided with the pseudo-second-order kinetic model, and the adsorption isotherm conformed to the Langmuir isotherm model. The optimized P(QP-DVB) particles exhibited well-defined spherical morphology and a uniform particle size distribution ranging from 15 to 30 µm. Nitrogen adsorption/desorption characterization revealed a high specific surface area of 674 m2 g−1 and a pore size distribution from 2 to 25 nm. In addition, the aforementioned microsphere underwent chemical regeneration and exhibits good reusability, thereby reducing both the economic costs and environmental impacts.