Degradation pathways, microbial community and electricity properties analysis of antibiotic sulfamethoxazole by bio-electro-Fenton system

[Display omitted] •The possible degradation pathways of SMX by the bio-electro-Fenton process were proposed.•It was worth noting that the absolute abundance of sul1 was the highest in effluent.•Different SMX concentrations altered the bacterial community composition of anode biofilm.•At the phylum level, Proteobacteria had the highest relative abundance.•When the SMX concentration of 25 mg/L, the power density reached 283.32 ± 16.35 mW/m2. Sulfamethoxazole (SMX) is a general antibiotic that is frequently identified in wastewater and surface water. In this study, the degradation and metabolic pathway of SMX by bio-electro-Fenton systems equipped with a CNT/r-FeOOH cathode were investigated. When initial SMX = 25 mg/L, the removal efficiency of SMX reached 94.66% by the bio-electro-Fenton system. The concentrations of sul1, sul2, sul3, sulA, intI1 and 16S rRNA genes were examined in effluents. Four out of the six ARGs analysed were detected. Among all quantified sul genes, sul1 and sulA were the most abundant. High-throughput sequencing revealed that the microbial communities and relative abundance at the phylum and genus levels were affected by different SMX concentrations. In addition, the intermediates were detected and the possible SMX degradation pathway by the bio-electro-Fenton process in the present system was proposed. Furthermore, the highest power density obtained was 283.32 ± 16.35 mW/m2 (SMX = 25 mg/L). This study provides an efficient and cost effective method for degrading antibiotics.