Construção e avaliação de células a combustível microbianas

Abstract

Microbial fuel cells (MFCs) are devices that promote the degradation of organic matter by means of microorganisms, with concomitant production of electric energy, presenting itself as a self-sustaining technology. It has potential use, for example, in the treatment of wastewater for the recovery of electric energy, in biosensors or in the construction of self-sustaining electronic devices. With the understanding of the mechanisms that relate the microbial metabolism and the generation of electricity, recent research focuses on optimizing the performance and efficiency of MFCs. The objective of the present work was to construct MFCs from three different architectures and to evaluate their operation using the Bacillus subtilis and Pseudomonas aeruginosa separately, operated with M9 medium. Were made two-chamber MFCs with graphite electrodes and Nafion membrane, being two in a batch system with volumes of 90 mL and 350 mL, and an intermittent feed system with a volume of 350 mL. In the study, the effect of oxidation was evaluated on the terminations of the copper wires connected to the graphite electrode; the effect of the use of the methylene blue mediator; and the operation of MFCs with intermittent power. The potential difference generation peak was 325mV and 10mV for electrodes with and without oxidation, respectively. The use of mediator promoted an approximate increase of 250% in the generation of potential difference. And MFCs in intermittent feeding presented stability of potential difference generation and glucose consumption.