Oxidative Desulfurization of Benzothiophene by Persulfate and Cu-Loaded g‑C3 N4 via the Polymerization Pathway

Turning aromatic sulfur impurities to value-added polymers is a promising technology for fuel desulfurization. In this study, Cu­(I,II)@g-C3N4 plates prepared via facile calcination show high reactivity in catalytic oxidation of benzothiophene (BT) by persulfate in a mixture of MeCN/H2O (v/v = 50/50...

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Published in:Industrial & engineering chemistry research 2023-03, Vol.62 (9), p.3909-3920
Main Authors: Zhi, Shao-Qi, Zhang, Jun-Yuan, Wu, Song-Hai, Zhu, Wen-Shuang, Shan, Yu-Dong, Liu, Yong, Han, Xu
Format: Article
Language:English
Subjects:
Kinetics, Catalysis, and Reaction Engineering
Online Access:Get full text
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Summary:Turning aromatic sulfur impurities to value-added polymers is a promising technology for fuel desulfurization. In this study, Cu­(I,II)@g-C3N4 plates prepared via facile calcination show high reactivity in catalytic oxidation of benzothiophene (BT) by persulfate in a mixture of MeCN/H2O (v/v = 50/50). Quenching experiments rule out the primary contributions of SO4 •–, •OH, and O2 •– to BT oxidation and confirm the presence of carbon-centered radicals during the desulfurization process. XPS and Raman analyses reveal that Cu­(I) and graphitic-N are reactive sites for persulfate activation, accompanied with moderate activation of the peroxo group in persulfate via the nonradical pathway. Solid characterizations indicate the formation of polybenzothiophene S,S-dioxide during the oxidation process, which further reveals that the moderately activated persulfate abstracts H from BT to form a BT radical cation, followed by subsequent polymerization of BT radical cations to a BT tetramer, and then the BT tetramer is further oxidized to a BT S,S-dioxide tetramer. The high electrochemical stability and pseudo-capacitive properties of the obtained polymers also imply their high potential to be used for capacitors. This work provides new insight on turning aromatic sulfur impurities in fuels to “treasures”.
ISSN:0888-5885
1520-5045
DOI:10.1021/acs.iecr.2c04484