Treated clinoptilolite-modified graphite felt bioanode microbial fuel cells for power generation and dye decolourisation

Abstract

One important factor in microbial fuel cells (MFCs) study is the anode. In MFCs, the anode acts as the key component in the generation of bioelectricity and power. Despite the fact that there have been some improvements in the electrochemical performance of MFCs in recent years, their low power generation is still deemed a major drawback. The effects of surface modifications of the anode as biofilm carrier on the performance of MFCs were investigated. This research focused on the role of the novel fabricated anode as support material for the adhesion of bacterial consortium (NAR-2) consisted of Citrobacter sp. A1, Enterobacter sp. L17 and Enterococcus sp. C1 were used in MFCs reactor for the decolourisation of Acid Red 27 (AR27) and the simultaneous generation of electricity. The performance of a modified anode fabricated using surfactant-treated clinoptilolite (S-TC) with common type of carbonbased material, namely treated clinoptilolite-modified graphite felt (TC-MGF) anode was evaluated with different MFCs constructions. Prior to the MFCs experiments, the modification of anode was successfully verified using different spectroscopic and microscopic techniques such as EDX, FESEM, ATR-FTIR and BET analysis. In addition, screening of parameters for the adhesion of bacterial consortium NAR-2 onto TC-MGF anode (NAR-2-bioanode) was accomplished. The newly-developed TCMGF bioanode was implemented in the dual-chamber (H-type) of the MFC. The performance of TC-MGF bioanode was compared to the results obtained using nonmodified graphite felt (BGF) bioanode. Maximum power densities for BGF and TCMGF bioanodes were 458.8 ± 5.0 and 940.3 ± 4.2 mWm-2, respectively. In the following experimental, a small MFC reactor was fabricated with TC-MGF bioanode to compare the performance of the MFC with commonly used fuel cell membranes, Nafion (N-117 and N-115), which were examined along with the N-212 membrane in a single-chamber cubic di-air cathode (S-CCD-AC) design. The power density and columbic efficiency of N-115 membrane (1022.5 mWm-2 - 35.4%) were significantly higher than the values obtained for the N-117 (592 mWm-2 - 15.6%) and N-212 (493 mWm-2 - 12.3%) membranes. A novel MFC reactor with TC-MGF bioanode novel design (Conch shell) using the N-115 membrane having an air-cathode upflow (A-CU) MFC, as a combination of upflow and MFC technologies was used to compare the presence and absence of a membrane design. The A-CUMFC with membrane-less at flow rate 0.6 mL min-1, anode distance of 0.5 cm and a concentration of AR27 at 900 mg L-1, high decolourisation rate (98%) achieved in a 60-day operation, was 40% higher than that of the membrane-MFC. The average maximum power density obtained (1250 mWm-2) using the membrane-less MFC was higher than that of the membrane-MFC (1108 mWm-2) during the 80-day operation with TC-MGF bioanode

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