N-doped graphitic C3N4 nanosheets decorated with CoP nanoparticles: A highly efficient activator in singlet oxygen dominated visible-light-driven peroxymonosulfate activation for degradation of pharmaceuticals and personal care products

Chencheng Dong; Zexiao Zheng; Zhiqiang Wang; Juhua He; Zhichao Ye; Xueqing Gong; Irene M C Lo

doi:10.1016/j.jhazmat.2021.125891

N-doped graphitic C₃N₄ nanosheets decorated with CoP nanoparticles: A highly efficient activator in singlet oxygen dominated visible-light-driven peroxymonosulfate activation for degradation of pharmaceuticals and personal care products

J Hazard Mater. 2021 Aug 15:416:125891. doi: 10.1016/j.jhazmat.2021.125891. Epub 2021 Apr 16.

Authors

Chencheng Dong¹, Zexiao Zheng¹, Zhiqiang Wang², Juhua He¹, Zhichao Ye¹, Xueqing Gong², Irene M C Lo³

Affiliations

¹ Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
² Key Laboratory for Advanced Materials, Centre for Computational Chemistry and Research Institute of Industrial Catalysis, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
³ Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China; Institute for Advanced Study, The Hong Kong University of Science and Technology, Hong Kong, China. Electronic address: cemclo@ust.hk.

PMID: 34492829
DOI: 10.1016/j.jhazmat.2021.125891

Abstract

CoP nanoparticle-loaded N-doped graphitic C₃N₄ nanosheets (CoP/N-g-C₃N₄) were fabricated via a facile three-step method to degrade pharmaceuticals and personal care products (PPCPs) via a visible-light-driven (VLD) peroxymonosulfate (PMS) activation system. 2 ppm carbamazepine (CBZ) can be removed completely within 10 min by the VLD-PMS system with a kinetic constant of k = 0.29128 min^-1, as 25.8 times compared to that under dark conditions (k = 0.01128 min^-1). The experimental and theoretical results showed that the doped graphitic N atoms could modulate the electronic properties of the g-C₃N₄ nanosheets. Subsequently, the Density Functional Theory (DFT) explained that CoP showed preference to bonding with the nitrogen atoms involved in the newly formed N˭N bond, and the Co‒N bond dramatically enhanced the transfer of photo-generated electrons from the N-g-C₃N₄ nanosheets. Electron paramagnetic resonance (EPR) tests show that singlet oxygen (¹O₂) plays a leading role in this case. Moreover, PMS molecules are also tended to be absorbed onto the electron-deficient carbon atoms near the newly formed N˭N bonds for PMS reduction, synergistically enhancing the degradation efficiency for CBZ and benzophenone-3 (BZP). The newly established VLD-PMS activation system was shown to treat the actual sewage in Hong Kong sewage treatment plants (STPs) very well. This work supplements the fundamental theory of radical and non-radical pathways in the sulfate radical (SO₄^•-)-based advanced oxidation process (SR-AOP) for environmental cleanup purposes.

Keywords: CoP/N-g-C(3)N(4); Non-radical way; PMS activation; PPCPs; Visible light.

Publication types

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

MeSH terms

Cosmetics*
Graphite*
Nanoparticles*
Peroxides
Pharmaceutical Preparations*
Singlet Oxygen

Substances

Cosmetics
Peroxides
Pharmaceutical Preparations
Singlet Oxygen
peroxymonosulfate
Graphite