Efficient removal of hexavalent chromium by nano-cerium-based adsorbent: The critical role of valence state and oxygen vacancy

Bing Hou; Jingwen Pan; Tao Shi; Zhenhua Dang; Shu Yang; Lei Wang; Baoyu Gao

doi:10.1016/j.jhazmat.2023.133020

Efficient removal of hexavalent chromium by nano-cerium-based adsorbent: The critical role of valence state and oxygen vacancy

J Hazard Mater. 2024 Feb 15:464:133020. doi: 10.1016/j.jhazmat.2023.133020. Epub 2023 Nov 17.

Authors

Bing Hou¹, Jingwen Pan², Tao Shi³, Zhenhua Dang¹, Shu Yang¹, Lei Wang⁴, Baoyu Gao⁵

Affiliations

¹ Key Laboratory of Eco-chemical Engineering, International Science and Technology Cooperation Base of Eco-chemical Engineering and Green Manufacturing, College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
² Key Laboratory of Eco-chemical Engineering, International Science and Technology Cooperation Base of Eco-chemical Engineering and Green Manufacturing, College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China. Electronic address: jwpan@qust.edu.cn.
³ Shandong Luqiao Group Co. Ltd., Jinan 250021, China.
⁴ Key Laboratory of Eco-chemical Engineering, International Science and Technology Cooperation Base of Eco-chemical Engineering and Green Manufacturing, College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China. Electronic address: inorchemwl@126.com.
⁵ Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, PR China.

PMID: 37984134
DOI: 10.1016/j.jhazmat.2023.133020

Abstract

Cerium-based adsorbents have been gradually used for the adsorption removal of highly toxic Cr(VI) from wastewater due to their low toxicity and wide working pH. However, the intrinsic properties of adsorbents contribute significantly to their adsorption performance, and the relationship between them needs to be clarified. Herein, series of nano-cerium based adsorbents (Ce@Cs) with different surface defects and Ce(III) content were prepared to explore their effects on the Cr(VI) adsorption capacity. Results showed that the optimal Ce@C performed well over a wide pH range of 2.0-12.0, and the calculated Cr(VI) adsorption capacity reached 302.43 mg/g at 45 ℃. Ce(III) and surface defects in cerium-based adsorbents exhibited an important influence on the Cr(VI) adsorption performance of Ce@Cs, and their contents showed a good positive correlation with the Cr adsorption capacity (R² =0.988 and 0.827). A series of evidences confirmed that the generated Ce(III) and oxygen vacancies could provide more sufficient coordination number to promote Cr(VI) complexation with Ce@Cs and lower the impedance of Ce@Cs to improve the reduction of Cr(VI) to low-toxic Cr(III). This work provides new insights into the Cr(VI) adsorption using cerium-based adsorbents, which helps to improve their potential in the purification of Cr(VI)-containing wastewater.

Keywords: Cerium-based adsorbent; Cr(VI) adsorption; Density functional theory; Oxygen vacancy; Valence state.