A novel membrane-less microbial fuel cell reactor using wood as container and separator to prevent air–cathode deterioration and biofouling

Abstract

In this study, we introduce a novel application of wood as the construction material for Microbial Fuel Cell (MFC) containers, developing what we term the Wooden Membrane-less Microbial Fuel Cell (WML-MFC). This innovative approach leverages the natural properties of wood to enhance the sustainability and cost-effectiveness of MFCs. Employing three different types of wood—pine, oak, and black locust—the WML-MFC design incorporates a carbon felt anode inside the wooden container and a carbon cloth cathode wrapped externally. This configuration not only protects the cathode from biofouling but also utilizes the inherent moisture management capabilities of wood to maintain operational stability. The performance of these wooden MFCs was assessed in terms of electricity generation and water treatment efficacy. Pine and oak containers achieved maximum power densities (MPD) of 35 mW/m^2 and 4 mW/m^2, respectively, with corresponding maximum open-circuit voltages of 551 mV and 269 mV. Black locust showed the least effective bioelectricity generation. COD removal efficiency was observed between 18 and 48% for pine and 3% to 39% for oak over hydraulic retention times of 24–48 h. Notable water loss due to moisture diffusion was recorded at 20%/day in pine and 6%/day in oak. Durability assessments through DMA and SEM analyses confirmed the suitability of wood as a container material, emphasizing the dual environmental and economic benefits of this WML-MFC design.