Visible-light-driven N-TiO2@SiO2@Fe3O4 magnetic nanophotocatalysts: Synthesis, characterization, and photocatalytic degradation of PPCPs

TiO2-based photocatalysis offers certain advantages like rapid degradation and mineralization of organic compounds. However, the practical applicability of photocatalysts in degradation of pharmaceuticals and personal care products (PPCPs) is still restricted by challenges including their limited photocatalytic activity under visible light and difficulty in their separation from suspension. To overcome these challenges, a visible-light-driven magnetic N-TiO2@SiO2@Fe3O4 nanophotocatalyst was developed through fine-tuning the pertinent factors (calcination temperature, Fe3O4 loading, and nitrogen doping) involved during synthesis process, on the basis of degradation of ibuprofen (a typical PPCP). The TEM-EDX, XRD and XPS analyses confirmed the successful synthesis of nanophotocatalyst. By comparing nanophotocatalyst's performance on ibuprofen under two visible light sources, i.e., compact fluorescent lamps (CFLs) and light emitting diodes (LEDs) of similar irradiance, CFLs of irradiance 320 mu W cm(-2) and peak emissive wavelength 543 nm served as a better source, resulting in 94% degradation. Furthermore, 93% of benzophenone-3 within 5 h and 71% of carbamazepine within 9 h was degraded under visible light emitted by CFLs. The superparamagnetic behavior of the nanophotocatalyst enabled its successful magnetic separation (95% efficiency) from the suspension within 20-25 min under an electromagnetic field of similar to 200 mT. (C) 2017 Elsevier B.V. All rights reserved.