Research and Study of Low-cost and Reliable Materials for Anode and Cathode Electrodes in Bioelectrochemical Systems (BESs): Scale Up of Materials for Real Application
Several sets of anodes carbonaceous and metallic materials have been investigated. Carbonaceous materials have been investigated and functionalized with chemical and electrochemical technique in order to increase oxygen and nitrogen functional groups that allow faster and higher bacteria attachment enhancing the biofilm electro-activity and electrons generation. Unfortunately, carbonaceous materials are very expensive and not enough robust to be deployed in long terms operation. As alternative, stainless steel (SS304) commercially available plain sheet has been investigated achieving similar performances compared to carbonaceous-based electrodes. The establishment of strictly anaerobic conditions in a short amount of time guaranteed also the conditions necessary to avoid metal corrosion. SS304 looks to be promising for large-scale applications due to the materials robustness and very reduced cost (order of magnitudes lower than carbonaceous-based groups). Further studies are currently in progress towards the direction of optimizing the SS304 material adding functional groups, hierarchically organized carbon structures and protecting the SS from long term possible deterioration and corrosion.
Several sets of cathodes have been deployed also in order to replace the more expensive and utilized platinum and guarantee long terms conditions. Cathodes based on cheap and high surface area activated carbon has been deployed for treating wastewaters. Other efficient, highly active and low cost catalysts based on non-PGM catalysts have been also studied with high performances and actually better behavior of platinum in SCMFC due to the establishment of highly alkaline conditions in proximity of the cathode. Moreover, those catalysts showed a better resistance to get pollutants from toxic compounds naturally present into wastewater. The low cost, high performance and reduced possibility to get poisoned make non-PGM a suitable choice of catalysts to be deployed in BESs.