A sandwiched denitrifying biocathode in a microbial fuel cell for electricity generation and waste minimization

Abstract

A denitrifying biocathode in a microbial fuel cell was developed to investigate the replacement of the costly Pt-coated abiotic cathodes for electricity generation. The denitrifying biocathode was sandwiched between the dual-anode systems. The study investigated the performance for simultaneous treatment of wastewater on the anode, biological denitrification on the cathode and the potential recovery of electrical energy. Autotrophic biofilms performed denitrification on the cathode using supplied electrons by the biodegradation of organics on the anode. Graphite granules were used as electrodes for biofilm attachment, and nafion membranes were used as separators between electrodes. The system achieved a volumetric power of 7 ± 0.4 W m -3 net cathodic compartment (NCC) with the simultaneous removal of 229.5 ± 18 mg L -1 COD on anode and 88.9 g m -3NCC day -1 nitrogen on cathode, respectively. The columbic efficiency for cathodic and anodic reactions was 98.9 ± 0.57 and 23.54 ± 0.87 %, respectively. This is a combined study for domestic wastewater treatment and biological denitrification in a compact MFC reactor.Further optimization of the system is desired to improve its performance and applicability.

A novel process of anodic water denitrification in an upflow tubular microbial fuel cell: effect of C/N ratio

“…claimed that the maximum power density was 35 W m –3 NCC in cathodic denitrification in an upflow MFC with an internal cathode. In another study by Al‐Mamun et al 65 . in a sandwiched denitrifying MFC, the maximum power density of 7 W m –3 NCC was reported.…”

“…For example, Clauwaert et al 18 claimed that the maximum power density was 35 W m -3 NCC in cathodic denitrification in an upflow MFC with an internal cathode. In another study by Al-Mamun et al 65 in a sandwiched denitrifying MFC, the maximum power density of 7 W m -3 NCC was reported. Virdis and co-workers 66 investigated the possibility of simultaneous carbon and nitrogen removal in an H-shaped MFC during cathodic denitrification, and they found that the nitrate concentration in cathode chamber dropped 97.1% at the highest current produced (at external resistance of 5 Ω and C/N ratio of 1.68), and a current density and power density of 133.3 A m -3 NCC and 34.6 W m -3 NCC, respectively, were achieved.…”

Experimental dataset on the effect of electron acceptors in energy generation from brewery wastewater via a microbial fuel cell

“…The corresponding power density curve was found from the plot of current density versus power density. The internal resistance of the MFC was determined according to the method reported somewhere else [10] . The COD removal efficiency of the MFC was calculated by employing 2000 mg/L COD wastewater sample in the anodic chamber followed by replacing it with 1500, 1000, and 500 mg/L COD concentrations.…”

“…Afterwards, the polarization curve was plotted in terms of current and power denisty vs voltage followed by power density curve which was intialy obtained from the tabulated value of current against power density. The internal resistance of the microbial fuel cell (MFC) was determined according to the method employed for polarization slope method which was reported somwhere else [2 , 3] . The removal efficiency of MFC for each COD concentration of the wastewater sample was calculated using equation (5).…”

Effect of the ammonia concentration on the performance of wetland microbial fuel cells

“…To reduce the operating costs there is an urgent requirement for developing improved cathodic aeration devices. At the same time, the use of plant composite bio-cathodes instead of precious metal cathodes as in the conventional CW-MFC, would allow to greatly reduce the electrode material costs, possibly improve the catalytic activity of the electrode and allow for the largescale production of CW-MFCs [6][7][8].…”