Novel low cost proton exchange membrane made from sulphonated biochar for application in microbial fuel cells

A novel low cost proton exchange membrane (PEM) was synthesized, using biochar derived from food waste by pyrolysis at 600 degrees C followed by sulphonation and using a poly vinyl alcohol based matrix, named as SBC-600, for application in microbial fuel cell (MFC). Membrane properties such as proton conductivity, ion transport number and oxygen diffusion coefficient were estimated and found to be 0.07 S cm(-1), 0.891 and 6.46 x 10(-9 )m(2)s(-1), respectively. Proton conductivity per unit cost of SBC-600 membrane (0.42 S cm(-1) $(-1)) was found to be 32 times higher than the Nation membrane. The MFCs with SBC-600 membrane (MFC-SBC) and Nation 117 as PEM (MFCN) exhibited chemical oxygen demand removal efficiencies of 81 +/- 6.6% and 88 +/- 4.9%, respectively. Power harvested per unit cost of membrane was 26 times higher for MFC-SBC (0.278 W $(-1)) than MPC-N (0.011 W $(-1)) offering a low cost alternative to the costly PEM presently used in MFCs for its field scale applications.