Enhanced azo dye reduction at semiconductor-microbe interface: The key role of semiconductor band structure

• Published in: Water research (Oxford) Vol. 248; p. 120846
• Main Authors: Shi, Hefei, Jiang, Xinbai, Wen, Xiaojiao, Hou, Cheng, Chen, Dan, Mu, Yang, Shen, Jinyou
• Format: Journal Article
• Language: English
• Published: 01.01.2024
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2023.120846

Low-energy environmental remediation could be achieved by biocatalysis with assistance of light-excited semiconductor, in which the energy band structure of semiconductor has a significant influence on the metabolic process and electron transfer of microbes. In this study, direct Z-scheme and type II heterojunction semiconductor with different energy band structure were successfully synthesized for constructing semiconductor-microbe interface with Shewanella oneidensis MR-1 to achieve acid orange7 (AO7) biodegradation. UV-vis diffuse reflection spectroscopy, photoluminescence spectra and photoelectrochemical analysis revealed that the direct Z-scheme heterojunction semiconductor had stronger reduction power and faster separation of photoelectron-hole, which was beneficial for the AO7 biodegradation at semiconductor-microbe interface. Riboflavin was also involved in electron transfer between the semiconductor and microbes during AO7 reduction. Transcriptome results illustrated that functional gene expression of Shewanella oneidensis MR-1 was upregulated significantly with photo-stimulation of direct Z-scheme semiconductor, and Mtr pathway and conductive pili played the important roles in the photoelectron utilization by Shewanella oneidensis MR-1. This work is expected to provide alternative ideas for designing semiconductor-microbial interface with efficient electron transfer and broadening their applications in bioremediation.