Development of miniature self-powered single-chamber microbial fuel cell and its response mechanism to copper ions in high and trace concentration

Copper ions are widely present in water environment and are involved in various biochemical reaction processes, causing irreversible damage to the human body. In this study, we design and establish a self-powered miniature single-chamber microbial fuel cell (SCMFC) reactor using xurography technology. Optimal volume of 188 mu L is obtained by controlling the distance between the anode and cathode. Copper ions in two concentration gradients are tested and good linear response curves are obtained. The opposite responses to copper ions in the trace concentration range (0-0.4 mg/L) and high concentration range (1.0-8.0 mg/L) are observed. The results show that at trace concentration range, the inhibitory effect of copper ions on the biofilm activity of micro-SCMFC is dominant; while high concentration copper ions are involved in chemical reactions that produce Cu2O, which may act as a catalyst and promote electron transfer. A good linear response to trace concentration (0-0.4 mg/L) of copper ions with detection limits of 0.05 mg/L is obtained in this study. It could be used in drinking water for trace copper ion detection. The investigation of the mechanisms provides the scientific basis for the design of the efficient detection of copper ions by SCMFC.

Automated summary

This study designs and establishes a self-powered miniature single-chamber microbial fuel cell (SCMFC) reactor for detecting copper ions in water. The study finds that copper ions have inhibitory effects on the biofilm activity of the microbial fuel cell at trace concentration range, while they are involved in chemical reactions that promote electron transfer at high concentration range.