Composites of Silica and Molecularly Imprinted Polymers for Degradation of Sulfadiazine

We report on the fabrication of silica/zinc oxide/zinc sulfide nanoparticles (SiO2/ZnO/ZnS NPs) wrapped with thermoresponsive molecularly imprinted polymers (TMIPs) for photocatalysis (PC) applications. TMIPs were prepared via surface-initiated reversible addition fragmentation chain transfer (SI-RAFT) polymerization of N-isopropylacrylamide (NIPAm) and ethylene glycol dimethacrylate (EGDMA), rendering the material solution accessible and temperature sensitive. Photodegradation of sulfadiazine (SD) was used as a probe to evaluate the effect of coated TMIPs on the PC performance of SiO2/ZnO/ZnS NPs. The results showed that TMIPs made SiO2/ZnO/ZnS NPs have an outstanding specific affinity PC activity toward template SD. Modification of SiO2/ZnO/ZnS NPs with Ag2S resulted in a tunable PC ability of the prepared material. For SI-RAFT conducted in a controlled manner, a thin layer of polymers (similar to 100 nm) formed around NPs was measured by a transmission electron microscopy (TEM). Also the polymers were characterized by Fourier transform infrared spectrometer and thermogravimetric analysis. Due to the specific binding of imprinted polymers, thermoresponsiveness of poly-NIPAm shells, and tunable PC ability of NPs cores, the obtained material catalyzed the original template SD with an appreciable selectivity over other structurally related antibiotics and the PC ability could be tunable by changing thte environmental temperature or NPs cores.