1. Electrochemical surface plasmon resonance approach to probe redox interactions between microbial extracellular polymeric substances and p-nitrophenol.
- Author
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Shao, Wei, Zhang, Xin, Li, Zheng-Hao, Xu, Juan, and Sheng, Guo-Ping
- Subjects
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SURFACE plasmon resonance , *OXIDATION-reduction reaction , *ELECTROLYTIC reduction - Abstract
Microbial extracellular polymeric substances with redox functional groups play a crucial role in the bio-conversion of pollutants, which can affect their reactivity toward diverse pollutants. However, the redox interactions between microbial EPS and pollutants have not addressed in depth due to the absence of essential analytical methodologies. In this study, we have developed an electrochemical-surface plasmon resonance (EC-SPR) system to investigate the interactions between EPS and p-nitrophenol (PNP) by simultaneously monitoring the electrochemical reaction and the binding kinetics. Moreover, in vitro PNP degradation experiments were performed in the presence of EPS across varying redox states to provide further verification of PNP reduction by EPS. The results indicated that direct electrochemical treatment successfully converted raw EPS (EPS raw) into reductive EPS (EPS red) and oxidized EPS (EPS ox), respectively. The EC-SPR system served as a powerful tool for probing redox interactions between EPS at distinct redox states and PNP. The binding affinity of EPS to PNP was related to the redox states of EPS, following the order of EPS red > EPS raw > EPS ox. EPS exhibited the capability to reduce PNP to p- aminophenol by donating electrons, and the reductive process highly depended on the redox states of EPS, primarily determined by their electron donating capacity. Importantly, direct electrochemical reduction treatment of EPS leads to a substantial improvement in the PNP removal efficiency from 33.8% (EPS raw) to 56.9% (EPS red). This work contributes to a comprehensive understanding of the critical role of EPS redox property in the conversion of refractory pollutants in aquatic environments. [Display omitted] • The interactions between EPS and PNP are investigated by EC-SPR. • EC-SPR simultaneously monitors electrochemical reaction and binding kinetics. • The reactivity of EPS towards PNP depends on their EDCs. • DER treament of EPS improves the reductive conversion of PNP. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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