N,S co-doped TiO2nanoparticles and nanosheets in simulated solar light for photocatalytic degradation of non-steroidal anti-inflammatory drugs in water: a comparative study

Abstract

Abstract Background In this study, highly visible-light photoactive nitrogen and sulfur co-doped TiO2 (N,S-TiO2) nanoparticles and nanosheets were synthesized via facile sol–gel and hydrothermal methods, respectively. The photocatalytic activities of N,S-TiO2 catalysts were evaluated by degradation of non-steroidal anti-inflammatory drugs, ibuprofen (IBP) and naproxen (NPX), under simulated solar irradiation. Results The N,S-TiO2 nanoparticle is a well-developed mesoporous structure that contains both anatase and rutile phases and a large BET surface area (132 m2 g−1). N,S-TiO2 nanosheets contain a complete anatase phase with a larger mesoporous structure and a smaller BET surface area (64 m2 g−1). The results showed that at catalyst loading of 2.0 g L−1 and pH 6, N,S-TiO2 nanoparticles can degrade 85% and 99.3% of IBP and NPX. At the same conditions, 71.6% of IBP and 99.1% of NPX were degraded by N,S-TiO2 nanosheets in this study. Conclusion The high photocatalytic activity of N,S-TiO2 may be due to synergistic effects of nitrogen and sulfur co-doping into TiO2, resulting in better separation of photogenerated electrons and holes and higher-visible light adsorption. Reusability tests of N,S-TiO2 showed that it could retain its catalytic activity even after six cycles. © 2015 Society of Chemical Industry