Photocatalytic Degradation of 4-Nitrophenol by C, N-TiO2: Degradation Efficiency vs. Embryonic Toxicity of the Resulting Compounds

Oluwatomiwa A Osin; Tianyu Yu; Xiaoming Cai; Yue Jiang; Guotao Peng; Xiaomei Cheng; Ruibin Li; Yao Qin; Sijie Lin

doi:10.3389/fchem.2018.00192

Photocatalytic Degradation of 4-Nitrophenol by C, N-TiO₂: Degradation Efficiency vs. Embryonic Toxicity of the Resulting Compounds

Front Chem. 2018 Jun 4:6:192. doi: 10.3389/fchem.2018.00192. eCollection 2018.

Authors

Oluwatomiwa A Osin^{1

2}, Tianyu Yu^{1

2}, Xiaoming Cai³, Yue Jiang¹, Guotao Peng¹, Xiaomei Cheng⁴, Ruibin Li⁵, Yao Qin⁴, Sijie Lin^{1

2}

Affiliations

¹ College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Shanghai Institute of Pollution Control and Ecological Security, Biomedical Multidisciplinary Innovation Research Institute, Shanghai East Hospital, Tongji University, Shanghai, China.
² UN Environment-Tongji Institute of Environment for Sustainable Development, Tongji University, Shanghai, China.
³ Center for Genetic Epidemiology and Genomics, School of Public Health, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Medical College of Soochow University, Suzhou, China.
⁴ Institute for Translational Nanomedicine, Shanghai East Hospital, Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai, China.
⁵ School for Radiological and Interdisciplinary Sciences (RAD-X), Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection Medical College of Soochow University, Suzhou, China.

Abstract

The photocatalytic activity of TiO₂ based photocatalysts can be improved by structural modification and elemental doping. In this study, through rational design, one type of carbon and nitrogen co-doped TiO₂ (C, N-TiO₂) photocatalyst with mesoporous structure was synthesized with improved photocatalytic activity in degrading 4-nitrophenol under simulated sunlight irradiation. The photocatalytic degradation efficiency of the C, N-TiO₂ was much higher than the anatase TiO₂ (A-TiO₂) based on absorbance and HPLC analyses. Moreover, using zebrafish embryos, we showed that the intermediate degradation compounds generated by photocatalytic degradation of 4-nitrophenol had higher toxicity than the parent compound. A repeated degradation process was necessary to render complete degradation and non-toxicity to the zebrafish embryos. Our results demonstrated the importance of evaluating the photocatalytic degradation efficiency in conjunction with the toxicity assessment of the degradation compounds.

Keywords: 4-nitrophenol; N-TiO2; embryonic toxicity; intermediate compounds; mesoporous C; photocatalytic degradation.