Effect of hydrofluoric acid-modified Co3O4/Y-type molecular sieves on MFC performance

Abstract

Microbial fuel cell (MFC) is a green technology that facilitates resource utilization of wastewater by generating electricity while degrading organic and ammonia nitrogen pollutants. The anode plays a crucial role in the MFC performance, demanding excellent electrochemical performance and high stability. In this paper, a new high-performance anode of Co3O4 composite Y molecular sieve (Co3O4/Y) was prepared, and the effect of the Co3O4 ratio and hydrofluoric acid (HF) modification on the Co3O4/Y performance was also investigated. The results showed that the Co3O4/Y, synthesized through the hydrothermal method with 30 wt% loading of Co3O4 followed by 10 % HF treatment, demonstrated superior electrochemical performance, which had the highest redox peak current density, the largest current response area, and the maximum exchange current density of 0.038 mA/cm2. Four anode catalysts of MFC, namely, blank carbon cloth (CC), Co3O4-CC, Co3O4/Y-CC, and H-Co3O4/Y-CC were prepared, and four groups of MFCs were constructed for the treatment of mixed wastewater consisting of the aged landfill leachate and shale gas fracturing wastewater. Notably, the H-Co3O4/Y-CC group showed the best performance in power generation, achieving a maximum stabilized output voltage (448 mV), a maximum power density (1179 mW/m2), and a minimum apparent internal resistance (466 Ω). Additionally, the removal rate of ammonia nitrogen exceeded 40 % in the mixed wastewater of the 4 groups of MFCs. This study provided a viable strategy for fabricating high-performance MFC anode materials and offered insights into the simultaneous disposal of domestic and industrial wastewater in MFCs.