TiO2-based catalysts for photocatalytic reduction of aqueous oxyanions: State-of-the-art and future prospects

Xuesong Zhao; Guan Zhang; Zhenghua Zhang

doi:10.1016/j.envint.2019.105453

TiO₂-based catalysts for photocatalytic reduction of aqueous oxyanions: State-of-the-art and future prospects

Environ Int. 2020 Mar:136:105453. doi: 10.1016/j.envint.2019.105453. Epub 2020 Jan 7.

Authors

Xuesong Zhao¹, Guan Zhang², Zhenghua Zhang³

Affiliations

¹ Institute of Environmental Engineering and Nano-Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong, China; Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong, China; School of Environment, Tsinghua University, Beijing 100084, China.
² School of Civil and Environmental Engineering, Harbin Institute of Technology, Shenzhen (HITSZ), Shenzhen 518055, PR China.
³ Institute of Environmental Engineering and Nano-Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong, China; Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong, China; School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: zhenghua.zhang@sz.tsinghua.edu.cn.

PMID: 31924583
DOI: 10.1016/j.envint.2019.105453

Abstract

Nowadays, an increasing discharge of oxyanions to the natural environment has been attracting worldwide attention. TiO₂-based photocatalysis is regarded as one of the most promising technologies for the conversion of toxic oxyanions (such as chromate, nitrate, nitrite, bromate, perchlorate and selenate) to harmless and/or less toxic substances in contaminated waters. Various types of TiO₂-based catalysts have been developed, and each of them exhibits its own advantages in catalytic reduction of oxyanions. However, the application of these nanostructured TiO₂ in real water bodies remains a challenge, with limitations associated with sunlight harvesting abilities, production costs, reuse stability and exposure risks. Herein, we aim to present a critical review on reported TiO₂-based photocatalytic reduction of aqueous oxyanions, provide a comprehensive understanding of the possible reaction pathways of formed active species, and evaluate the reduction performance of different types of TiO₂-based catalysts. In addition, the impact of operating parameters (such as solution pH, temperature, dissolved oxygen and coexisting substances) on catalytic reduction performance is discussed. Furthermore, the perspectives of TiO₂-based photocatalytic reduction of oxyanions are also proposed.

Keywords: Free radical; Oxyanions; Photocatalytic reduction; Titanium dioxide (TiO(2)); Water treatment.

Publication types

Research Support, Non-U.S. Gov't
Review

MeSH terms

Catalysis
Titanium*
Water
Water Pollutants, Chemical*

Substances

Water Pollutants, Chemical
Water
titanium dioxide
Titanium