A comparison of long-term fouling performance by zirconia ceramic filter and cation exchange in microbial fuel cells

The long-term performance of non-ion selective separators, zirconia ceramic filter (ZCF) with a various pore size such as 0.14 μm ZCF1, 150 kDa ZCF2 and 5 kDa ZCF3 were compared to commercial cation exchange membrane (CEM), Nafion 117 in microbial fuel cells. The ZCF3 generated the highest performance of 2800 ± 14.5 mWm−2 (5.9 Am−2) compared to CEM: 1800 ± 17.8 mWm−2, 4.0 Am−2. Meanwhile, the CEM exhibited maximum power decline during the reverse sweep (61.7%) when analyzed using the bi-directional polarization method. The non-ion selective membranes displayed reduced in maximum power decline during the reverse sweep (ZCF1 50%, ZCF2 40% and ZCF3 42.8%). In addition, the ZCF3 showed the highest proton conductivity and water uptake, 0.863 × 10−1 Scm−1 and 93.7% respectively, followed by ZCF2 (0.729 × 10−1 Scm−1, 80.98%), ZCF1 (0.624 × 10−1 Scm−1, 73.99%) and Nafion 117 (0.367 × 10−2 Scm−1, 57.07%). The ZCF3 appeared as an efficient material for electrochemical active bacteria, maintaining the high power of 1600 mWm−2, compared to CEM: 600 mWm−2 after eight months’ operation under batch mode. The long-term operation of MFCs was affected by the reduction of power output, caused by the increase in the thickness of the biofilm.