CoOOH with a highly negative CB band for visible-light-driven photocatalytic degradation of refractory organic pollutants in peroxymonosulfate system: Enhanced performance and multi-path synergetic mechanisms

Lu Zhang; Lunan Ju; Xiaodan Li; Ayi Guli; Cong Lyu

doi:10.1016/j.jhazmat.2023.132403

CoOOH with a highly negative CB band for visible-light-driven photocatalytic degradation of refractory organic pollutants in peroxymonosulfate system: Enhanced performance and multi-path synergetic mechanisms

J Hazard Mater. 2023 Oct 15:460:132403. doi: 10.1016/j.jhazmat.2023.132403. Epub 2023 Aug 25.

Authors

Lu Zhang¹, Lunan Ju¹, Xiaodan Li², Ayi Guli³, Cong Lyu⁴

Affiliations

¹ Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130026, PR China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun 130026, PR China.
² China Northeast Municipal Engineering Design and Research Institute Co. Ltd., Changchun 130021, PR China.
³ Institute Co., Ltd. of Hydropower Survey and Design, Urumqi Branch of Xinjiang Yili, 831200, PR China.
⁴ Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130026, PR China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun 130026, PR China. Electronic address: lvcong@jlu.edu.cn.

PMID: 37672996
DOI: 10.1016/j.jhazmat.2023.132403

Abstract

To date, cobalt ions/oxides were proven to be the best peroxymonosulfate (PMS) activator in the homogeneous/heterogeneous system. Interestingly, we found out that CoOOH with a narrow band gap (2.18 eV) and highly negative CB band (-1.73 eV) showed a good potential to be a visible-light-driven photocatalyst for PMS activation. The results turned out that the reaction rate constant of typical refractory contaminants in the Vis-CoOOH/PMS system was about 2-5 times higher than that in the Dark-CoOOH/PMS system. The photogenerated electron (e^-) and hole (h⁺) can react with PMS, which significantly facilitates charge separation. Meanwhile, the e^- on the highly negative CB band can react with oxygen to generate O₂•^-, which simultaneously accelerates the cycle Co(III)/Co(II) to generate radicals (O₂•^-, •OH and SO₄•^-) and non-radical (¹O₂). As a result, multiple ROS was involved in the degradation of contaminants. Especially, O₂•^- with a longer half-life over ¹O₂ is identified as the dominant ROS, enhancing the utilization of radicals and the effective attack with contaminants. Therefore, this study first reports the great potential of CoOOH as a visible-light photocatalyst and reveals the multi-path mechanism of the synergistic visible-light-driven photocatalysis and PMS activation for removing refractory contaminants in wastewater.

Keywords: CoOOH; Peroxymonosulfate; Super oxygen radical; Triclosan; Visible light.