Dou Y, Yan T, Zhang Z, Sun Q, Wang L, Li Y. Heterogeneous activation of peroxydisulfate by sulfur-doped g-C
3N
4 under visible-light irradiation: Implications for the degradation of spiramycin and an assessment of N-nitrosodimethylamine formation potential.
JOURNAL OF HAZARDOUS MATERIALS 2021;
406:124328. [PMID:
33144012 DOI:
10.1016/j.jhazmat.2020.124328]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/29/2020] [Accepted: 10/16/2020] [Indexed: 06/11/2023]
Abstract
In this study, peroxydisulfate (PDS) was activated by synthesized sulfur-doped g-C3N4 (SCN) under visible-light irradiation and was adopted to enhance the removal of spiramycin, which is an important precursor of N-nitrosodimethylamine (NDMA). Specifically, 95.4% of spiramycin (≤10 mg/L) was removed in 60 min under the conditions of an initial value of pH of 7.0, an SCN dose of 1.0 g/L, and a PDS dose of 200 mg/L, and its degradation fitted well with the pseudo first-order kinetics. Electron paramagnetic resonance analysis and trapping experiments confirmed that ·O2- and h+ were the main oxidizers for the degradation of spiramycin, and ·SO4- and ·OH also participated in the removal of spiramycin. The removal of spiramycin in the PDS/SCN visible-light catalytic system occurred through three different pathways: aldehyde oxidation, cleavage of C-O bond and demethylation. Notably, 61.4% of NDMA formation potential (FP) was reduced after the reaction. The SCN catalyst was stable and its catalytic performance was excellent in the PDS/SCN system, as the spiramycin removal efficiency decreased only slightly from 95.4% to 87.3% after being reused three times. Therefore, our study not only provides an alternative method for removing spiramycin but can also can significantly reduce NDMA FP.
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