标题: Activation of Peroxydisulfate on Carbon Nanotubes: Electron-Transfer Mechanism
作者: Ren, W (Ren, Wei); Xiong, LL (Xiong, Liangliang); Yuan, XH (Yuan, Xuehong); Yu, ZW (Yu, Ziwei); Zhang, H (Zhang, Hui); Duan, XG (Duan, Xiaoguang); Wang, SB (Wang, Shaobin)
来源出版物: ENVIRONMENTAL SCIENCE & TECHNOLOGY 卷: 53 期: 24 页: 14595-14603 DOI: 10.1021/acs.est.9b05475 出版年: DEC 17 2019
摘要: This study proposed an electrochemical technique for investigating the mechanism of nonradical oxidation of organics with peroxydisulfate (PDS) activated by carbon nanotubes (CNT). The electrochemical property of twelve phenolic compounds (PCs) was evaluated by their half-wave potentials, which were then correlated to their kinetic rate constants in the PDS/CNT system. Integrated with quantitative structure-activity relationships (QSARs), electron paramagnetic resonance (EPR), and radical scavenging tests, the nature of nonradical pathways of phenolic compound oxidation was unveiled to be an electron-transfer regime other than a singlet oxygenation process. The QSARs were established according to their standard electrode potentials, activation energy, and pre-exponential factor. A facile electrochemical analysis method (chronopotentiometry combined with chronoamperometry) was also employed to probe the mechanism, suggesting that PDS was catalyzed initially by CNT to form a CNT surface-confined and -activated PDS (CNT-PDS*) complex with a high redox potential. Then, the CNT-PDS* complex selectively abstracted electrons from the co-adsorbed PCs to initiate the oxidation. Finally, a comparison of PDS/CNT and graphite anodic oxidation under constant potentials was comprehensively analyzed to unveil the relative activity of the nonradical CNT-PDS* complex toward the oxidation of different PCs, which was found to be dependent on the oxidative potentials of the CNT-PDS* complex and the adsorbed organics.
地址: [Ren, Wei; Xiong, Liangliang; Yuan, Xuehong; Yu, Ziwei; Zhang, Hui] Wuhan Univ, Hubei Environm Remediat Mat Engn Technol Res Ctr, Dept Environm Sci & Engn, Wuhan 430079, Hubei, Peoples R China.
[Ren, Wei; Duan, Xiaoguang; Wang, Shaobin] Univ Adelaide, Sch Chem Engn, Adelaide, SA 5005, Australia.
通讯作者地址: Zhang, H (通讯作者)，Wuhan Univ, Hubei Environm Remediat Mat Engn Technol Res Ctr, Dept Environm Sci & Engn, Wuhan 430079, Hubei, Peoples R China.
Duan, XG (通讯作者)，Univ Adelaide, Sch Chem Engn, Adelaide, SA 5005, Australia.
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