Producing Electricity Using a Microbial Fuel Cell Fed with Feedstock Chemicals Produced from the Photocatalysis of a Lignin Model Chemical

Lignin, an abundant renewable chemical, is a complex recalcitrant structure which is difficult to degrade using biological methods. In this study, electricity production from a lignin model compound was examined using a two step process which included producing a chemical feedstock produced by photocatalysis followed by the bio-electrochemical conversion in a microbial fuel cell (MFC). The study was conducted using sodium lignosulfonate (LS)), a model lignin compound, at a concentration of 500 mg L–1 (683 mg COD L–1). In the photocatalytic degradation process, titanium dioxide (TiO2) plus ultraviolet light was used to convert the model lignin chemical into short chain carbon chemicals. The effluent from the photocataly tic degradation process was fed into a single chamber air-cathode microbial fuel cell (SCMFC) to generate electricity. The SCMFCs operating at 21 °C generated maximum current and power densities of 3925±280 mA m–3 and 1164±208 mW m–3, respectively. The corresponding maximum current and power densi ties normalized to the cathode area were 560±40 mA m–2 and 166±30 mW m–2, respectively. The two step process was able to remove 86% of the initial COD in the LS. This study demonstrated that combining photocatalysis together with a bio-electrochemical process was useful for degrading a model lignin chemical.