Self-Competitive Adsorption Behavior of Arsenic on the TiO2 Surface

Zhigang Wei; Zhixin Zhou; Yue Liu; Shiyun Chen; Yang Wu; Huixia Jian; Zhanchang Pan; Guanghui Hu

doi:10.1021/acsomega.3c03214

Self-Competitive Adsorption Behavior of Arsenic on the TiO₂ Surface

ACS Omega. 2023 Aug 18;8(34):31201-31214. doi: 10.1021/acsomega.3c03214. eCollection 2023 Aug 29.

Authors

Zhigang Wei¹, Zhixin Zhou¹, Yue Liu¹, Shiyun Chen¹, Yang Wu², Huixia Jian¹, Zhanchang Pan¹, Guanghui Hu¹

Affiliations

¹ School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, P.R China.
² College of Chemistry, Liaoning University, Shenyang 110036, P. R. China.

Abstract

TiO₂ is a commonly used material to remove arsenic from drinking water by adsorption as well as photocatalytic oxidation (PCO). In the present paper, arsenic adsorption and PCO at different pH environments are studied on the (1 1 0) facet of rutile TiO₂ (r-TiO₂). A self-competitive adsorption (SCA) behavior of arsenic is observed; i.e., arsenic species compete to adsorb on the surface. Related DFT calculations are carried out to simulate adsorption. SCA behavior is the key to connecting calculation results with experimental results. Furthermore, PCO of arsenite is performed at different pH values. Of note, PCO is related to adsorption; namely, the adsorption process determines the whole PCO reaction speed. Therefore, SCA is also helpful for the PCO reaction. The SCA behavior is useful not only for arsenic on r-TiO₂ but also for arsenic on anatase TiO₂ (a-TiO₂). It may be helpful to further study arsenic adsorption and PCO on other materials such as Fe₂O₃ and MnO₂. The SCA behavior extends our understanding of arsenic and provides new insights into arsenic removal and its cycle in nature.