Depletion of double-layer coated nano-TiO2 and generation of reactive oxygen species in the presence of ethanol under simulated solar irradiation

作者：Wu, Wei; Xiang, Qian; Wu, Zihao; Shan, Guoqiang^*; Zhu, Lingyan^*

来源：NanoImpact, 2018, 11: 164-169.

DOI：10.1016/j.impact.2018.08.004

• Coated nano-TiO2
• Ethanol
• Reactive oxygen species
• Photocatalytic

Nano-TiO2 is demanded in a large quantity in pharmaceutical and personal care products. To protect human from adverse effects induced by reactive oxygen species (ROS) generated by nano-TiO2 under solar light irradiation, it is usually coated by an inorganic layer and sometimes one additional polymeric layer. In this study, a commercial double-layer coated nano-TiO2, named STR-100C-LP (abbreviated as STR), was used to access its transformation and restoration of photoactivity in aqueous medium, comparing with pristine P25 nano-TiO2. The organic coating made STR surface hydrophobic, while 1% (v/v) organic solvents, such as ethanol, methanol, promoted its dispersion. A series of characterization techniques indicated that dissolution effect of solvents and solar light irradiation could damage the organic and inorganic coating layers of STR. Thus, STR regained its photoactivity and produced ROS species, such as hydroxyl radicals and superoxide radical species. The results strongly suggest that the double coating layers of nano-TiO2 were unstable in the presence of organic solvent and solar irradiation. This would result in recovery of its photoactivity and generation of ROS, finally changing its transport and fate in aquatic environment.

• 出版日期2018-7
• 单位南开大学