Chinese Journal of Catalysis ›› 2019, Vol. 40 ›› Issue (5): 673-680.DOI: 10.1016/S1872-2067(19)63285-7

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Exploring a broadened operating pH range for norfloxacin removal via simulated solar-light-mediated Bi2WO6 process

Meijuan Chena,b, Yu Huangb, Wei Chuc   

  1. a School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China;
    b State Key Laboratory of Loess and Quaternary Geology(SKLLQG), Key Laboratory of Aerosol Chemistry & Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, Shaanxi, China;
    c Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
  • Received:2018-11-13 Revised:2018-12-13 Online:2019-05-18 Published:2019-03-30
  • Contact: S1872-2067(19)63285-7
  • Supported by:

    This work was supported by the National Science Foundation of China (41877481, 41503102), the open project of the State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Science (SKLLQG1729), the China Postdoctoral Science Foundation (2018M643669), the Fundamental Research Funds for the Central Universities (2018249), and the "Hundred Talent Program" of the Chinese Academy of Sciences.

Abstract:

Semiconductor photocatalysis can be operated over a narrow pH range for wastewater treatment. In this study, a simulated solar-light-mediated bismuth tungstate (SSL/Bi2WO6) process is found to be effective for norfloxacin degradation over a narrow pH range. To broaden the operating pH range of the SSL/Bi2WO6 process, an NH4+ buffer system and an Fe3+ salt were introduced under extremely basic and acidic pH conditions, respectively. The NH4+ buffer system continuously supplied hydroxyl ions to generate·OH radicals and prevented acidification of the solution, resulting in improved norfloxacin removal and mineralization removal under alkaline conditions. In contrast, the Fe3+ salt offered an additional homogeneous photo-sensitization pathway. The former treatment assisted in norfloxacin decay and the latter increased the collision frequency between the photo-generated hole and hydroxyl ions. Moreover, the effect of parameters such as pH and Fe3+ dosage was optimized.

Key words: Bismuth tungstate, Broadened operating pH, Norfloxacin, Photocatalysis, Water