Environmentally friendly low-cost membranes for micro and meso-scale bioelectrochemical systems

GONZÁLEZ PABON MARÍA JESUS; CORTON EDUARDO; FIGUEREDO FEDERICO; MARTÍNEZ DIANA

Ciudad de México

Congreso; XVIII International Congress of the Mexican Hydrogen Society; 2019

Sociedad Mexicana del Hidrogeno

Microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) are well known bioelectrochemical systems (BESs) that can be used to produce electricity, and hydrogenrespectively, by means of microbial metabolic activity. Nonetheless, new strategies forconstructions, start up, operation and maintenance are required to improve BESs efficiency andcommercial feasibility. At that point, BESs manufacturing materials (electrodes and membranes)represent the main bottleneck for industrial use and scalable real-world applications. Then, oneof the challenges to make MFCs and MECs a viable technology is to obtain low cost andenvironmentally sound materials to fabricate them. In this work we synthesized membranes by asimple procedure: using solution casting and solvent evaporation technique, involving low priceand biodegradable materials such as poly (vinyl alcohol) (PVA), chitosan (CS) and PVA:CS, allcross-linked with sulfuric acid. The synthesized membranes were characterized by SEM and EIS,as well as their water uptake, oxygen diffusion and MFC performance, and compared to Nafion®117, as our reference/control membrane. Conductivity values of the three synthesizedmembranes were lower than Nafion® 117. However, PVA and PVA:CS show lower oxygenpermeability in comparison to Nafion® 117 membranes, a strong advantage in order to maintainanaerobic conditions in the anodic compartment of MFCs. Membranes were first studied in atypical meso-scale H-Type MFCs with LB medium containing E. coli (OD = 1). Our results showthat CS membrane has the best current output performance (76.1 ± 11.9 mA/m2). On the otherhand, PVA:CS membranes outperform Nafion® 4 times (power production, 20.8 ± 2.9 mW/m2)while being 75 times more economic. Furthermore, the best membrane in terms of powergeneration (PVA:CS) were used to made disposables paper-based micro-scale devices (16 µL),were power production was 10.5 ± 0.7 µW/cm3. PVA:CS membranes presented here can beuseful to fabricate miniaturized and biodegradable MFC, for analytical uses as biosensors, andmeso-systems capable to produce energy in a sustainable mode.