Bimetallic nitrogen-doped porous carbon derived from ZIF-L&FeTPP@ZIF-8 as electrocatalysis and application for antibiotic wastewater treatment

Microbial fuel cells (MFCs) systems are up-and-coming technologies for renewable energy production and wastewater treatment simultaneously. However, the inactive oxygen reduction reaction (ORR) on the cathode markedly limits the functioning of MFCs. Therefore, the cathodic catalyst is one of the crucial components in MFCs, this paper presents the removal of the antibiotic sulfamethoxazole (SMX) from water using single-chamber MFCs with Fe-Co-C/N as electrocatalysis. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were conducted to illustrate the structure and elemental composition of Fe-Co-C/N. The results obtained by the rotating disk electrode (RDE) method showed an extraordinary electrocatalytic activity of Fe-Co-C/N towards ORR in O2-saturated 0.1 M KOH. Furthermore, the degradation of SMX by MFCs that applied modified electrodes was also studied. The results demonstrated that using Fe-Co-C/N as air-cathode catalysts exhibited the degradation efficiency of 61.64% towards 6 mg/L SMX with 48 h. In addition, cyclic voltammetry (CV) analysis showed that the peak current of the biofilm in the PBS solution (without adding SMX) was significantly higher than that of the solution with SMX addition at 6, 18, and 30 mg/L. Moreover, MFC performance was also evaluated by measuring electrochemical impedance spectroscopy (EIS), power generation, and polarization curves. Last but not least, the high-throughput sequencing-based metagenomic technique was used to explore the microbial community diversity, functional genes in MFCs, and fate of ARGs. SMX addition raised the abundances of sul1 and sul2 as resistance genes, which enhanced microbial resistance, the coping capability of SMX toxicity, and the adjustment of the damage from SMX. The obtained results suggest that Fe-Co-C/N is a feasible catalyst for MFC cathodes owing to its satisfactory performance in terms of SMX wastewater treatment and power production.

Automated summary

This study investigated the removal of the antibiotic sulfamethoxazole (SMX) from water using Fe-Co-C/N as electrocatalysis in MFCs. The Fe-Co-C/N catalyst exhibited excellent electrocatalytic activity towards oxygen reduction reaction (ORR), leading to efficient SMX degradation in MFCs. Additionally, the study explored the impact of SMX on MFC performance and microbial community diversity.