Efficient Biodegradation of Trimethoprim and Transformation Mechanism Using the Photoelectrocatalytic System

Abstract

In this study, the coupling of three-electrode photocatalytic and microbial fuel cell system (PMFC) was established for trimethoprim degradation, to achieve efficient degradation and electrical energy production simultaneously. Rapid degradation and enhanced mineralization of TMP was obtained in the PMFC, and the degradation (by 90%) rate and mineralization of TMP were 0.125 mg/(L·h) and 62%, which were 1.7 and 1.4 times higher than those of traditional MFC, respectively. LC-MS and 3D-EEM analysis identified the intermediates of TMP were different in the two system, and three degradation pathways was inferred in the PMFC. The electricity characteristic was investigated and superior electrical production and higher electron transfer efficiency were observed in the PMFC, resulting in a maximum power density of 75.1 mW/m2 and a maximum voltage of 0.225 V. The microbial community structure was analyzed to investigate the change of functional flora. The results showed that microbial richness was higher in the PMFC, and the dominant species were enriched and coexisted, involving Truepera, Bradyrhizobium, Rhodopseudomonas, Brucella, Sphingopyxis and Hyphomicrobium. Furthermore, CCA analysis revealed a mutual promotion of TMP degradation and electricity production with the involvement of these active genera. In conclusion, this novel technology is an excellent alternative for treating wastewater containing TMP with simultaneous power generation.

Keywords: Trimethoprim, Photoelectrocatalytic, Degradation Mechanism, Pathway, Microbial structure