The application of ferrous and graphitic N modified graphene-based composite cathode material in the bio-electro-Fenton system driven by sediment microbial fuel cells to degrade methyl orange

Abstract

In this work, the ferrous (Fe 2+ ) and graphitic N modified graphene-based composite cathode materials (N-rGO/Fe 3 O 4 ) were developed through an in-situ reduction method, aiming to facilitate the two-electron pathway in the oxidation-reduction process. This approach generated a specific concentration of H 2 O 2 , enabling the construction of a sediment bio-electro-Fenton system using Fe 2+ released from the cathode materials. Notably, this system operates without the need for proton exchange membranes. During the cathode material preparation, the utilization of Fe 2+ as a reduction agent for graphene oxide (GO), triggered ammonia water to form graphitic N in graphene sheets. This addition enhanced the two-electron pathway, resulting in increased H 2 O 2 production. Specifically, when the Fe 2+ concentration was maintained at 0.1 mol/L, precise preparation of N-rGO/Fe 3 O 4 occurred, leading to a maximum output voltage of 0.528 V and a maximum power density of 178.17 mW/m 2 . The degradation of methyl orange (MO) reached 68.91% within a 25-h period, a phenomenon contributed to the presence of graphitic N in the graphene sheets. H 2 O 2 , a byproduct of the two-electron pathway in cathode oxidation reduction reaction, played a crucial role in constructing the bio-electro-Fenton system. This system, in conjunction with Fe 2+ released from N-rGO/Fe 3 O 4 , facilitated the complete degradation process of MO.

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Identifiers

DOI

10.1016/j.heliyon.2024.e24772

PubMed

38333867

Journal

Heliyon

Year

2024