Bioelectricity production and bioremediation from sugarcane industry wastewater using microbial fuel cells with activated carbon cathodes

Abstract

Clean energy and water are major challenges to meet for sustainable development. Microbial Fuel Cells or MFCs can treat wastewater with the treatment process becoming a method for capturing energy in the form of bioelectricity. In this work, biomass derived Activated Carbon was used as the MFC cathode with carbon yarn as the brush anode. Sugarcane processing plant wastewater was used to evaluate bioelectricity generation and contamination removal over multiple cycles. System performance was stable, this is attributed to absence of carboxylic acid functional group on cathode surface and the sufficiently developed bacteria biofilm on the anode. The reactors used were able to facilitate organic matter degradation continually. MFC reactors developed open circuit voltage of 870 ± 20 mV, and power density of 563 ± 30 mW/m2 with external resistors, having current density of 0.79 mA/m2. The chemical contamination of the wastewater was reduced from 1201 ± 60 mg/l to 240 ± 31 mg/l with average removal of 81%, with BOD removal efficiency of 86%. The utility of biomass derived Activated Carbon as a cathode material was evaluated with BET analysis, having a surface area of 230.131 m2/g for oxygen reduction. Surface feature includes distinct mesoporous structures for the growth of heterotrophs. Additionally, FTIR analysis of cathodes revealed the presence of heteroatoms on the carbon matrix which adds stability to its surface chemistry. This makes the cathode surface suitable for operation in real time conditions without corroding metal mesh collectors on which they are coated.

Keywords

• Activated carbon
• Biomass
• BOD
• COD
• Sugarcane
• Wastewater