Elucidating GO/iron series mediated stable flora and electron transfer under different COD/SO42− ratios

• Published in: Journal of water process engineering 2024-07, Vol.64, p.105736, Article 105736
• Main Authors: Li, Ke, Cao, Qiliang, Zhang, Hui, Jin, Yuqi, Liang, Qiaochu, Lan, Huixia, Zhang, Wudi, Zhang, Yang
• Format: Article
• Language: English
• Subjects: Anaerobic treatment; Iron series; Microbial electrochemistry; Sulfate
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.105736

The utilization of graphene oxide (GO)/iron series can immensely ameliorate the adverse implications during the anaerobic treatment of sulfate-containing organic wastewater (SCOW), and improve the system performance. However, systematic studies on strengthening mechanism of different iron series are scarce. Under the conditions of COD/SO42− ratios of 2.5, 1.25, and 0.8, the effects of GO/Fe0, GO/Fe3O4 and GO/Fe2O3 on anaerobic treatment of SCOW were studied. And it elaborated the strengthening mechanisms of GO/iron series from two aspects: symbiosis microbial communities and extracellular electron transfer. The results demonstrated that the existence of each GO/iron series enhances the sulfate impact resistance of the anaerobic system. Among them, GO/Fe0 shows the optimum strengthening effect. The buffering effect of GO/iron series was the most obvious when the COD/SO42− ratio is 1.25. The soluble iron produced by the iron series reduces the poison of sulfides on the system. Furthermore, it reduces the impedance of the system, thereby enhancing the efficiency of intra/extra cellular electron transfer. Moreover, GO/iron series improve the stability of the flora, promoting the syntrophy symbiosis of acidogenic, methanogenic and sulfate-reducing bacteria. This study provides parameters and scientific basis for the application of innovative techniques in the treatment of SCOW. [Display omitted] •GO/irons can alleviate the impact of sulfate on the anaerobic system.•GO/Fe0 have the best enhancement effect in different GO/irons.•GO/irons improved the microbial community structure.•GO/irons increased the extracellular electron transfer rate of the system.