Janus particles with pH switchable properties for high-efficiency adsorption of PPCPs in water

Pharmaceuticals and personal care products (PPCPs) are emerging pollutants and have received increasing attention in recent years. The regeneration of conventional adsorption materials used to remove PPCPs involves the desorption of secondary organic pollution, which is harmful and problematic. In this work, the impact of pH-responsive magnetic Janus particle catalysts on PPCPs’ performance of high-efficiency adsorption and degradation was studied. Magnetic core-shell Fe 3 O 4 @SiO 2 nanoparticles were prepared via the STÖBER method. Polylactic acid (PLA) was grafted using a template method, and the polymerization of pH-responsive monomer 2-(diethylamino)ethyl methacrylate (DEAEMA) was initiated to obtain the pH-responsive magnetic Janus particles (Janus-Fe-P). SEM (scanning electron microscopy), particle size analysis, TEM (transmission electron microscopy), and N 2 adsorption-desorption tests were used to characterize the morphology, magnetic property, and pH-responsive performance of the Janus-F-P. The Janus-F-P was used in the adsorptions of two kinds of representative PPCPs, i.e., hydrophilic (antipyrine) and hydrophobic (tiamulin), under neutral conditions. Commercially available NORIT CN activated carbon was used for comparison, and the adsorption results showed that the adsorption efficiency of Janus particles was higher than that of activated carbon. Therefore, Janus-F-P could be used to efficiently catalyze the degradation of adsorbed PPCPs in the Fenton/hydroxylamine system. The removal rate of PPCPs was above 85 % after repeated use (5 times).