title: Accelerated OH(-) transport in activated carbon air cathode by modification of quaternary ammonium for microbial fuel cells.
abstract: Activated carbon (AC) is a promising catalyst for the air cathode of microbial fuel cells (MFCs) because of its high performance and low cost. To increase the performance of AC air cathodes, the acceleration of OH(-) transport is one of the most important methods, but it has not been widely investigated. Here we added quaternary ammonium to ACs by in situ anchoring of a quaternary ammonium/epoxide-reacting compound (QAE) or ex situ mixing with anion exchange resins in order to modify ACs from not only the external surface but also inside the pores. In 50 mM phosphate buffer solution (PBS), the in situ anchoring of QAE was a more effective way to increase the power. The highest power density of 2781 ± 36 mW/m(2), which is 10% higher than that of the control, was obtained using QAE-anchored AC cathodes. When the medium was switched to an unbuffered NaCl solution, the increase in maximum power density (885 ± 25 mW/m(2)) was in accordance with the anion exchange capacity (0.219 mmol/g). The highest power density of the anion exchange resin-mixed air cathode was 51% higher than that of the control, indicating that anion exchange is urgently needed in real wastewaters. Excess anchoring of QAE blocked both the mesopores and micropores, causing the power output to be inhibited.
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria and Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University , No. 94 Weijin Road, Nankai District, Tianjin 300071, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Cuijuan
authors.initials: C
authors.lastname: Feng
authors.forename: Ning
authors.initials: N
authors.lastname: Ding
authors.forename: Qingrui
authors.initials: Q
authors.lastname: Zhang
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Li
authors.forename: Yueyong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Qixing
authors.initials: Q
authors.lastname: Zhou
mesh_terms: D000388:Air; D001674:Bioelectric Energy Sources; D002021:Buffers; D002384:Catalysis; D002606:Charcoal / Q000737:chemistry*; D004560:Electricity; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000737:chemistry*; D007477:Ions; D008855:Microscopy, Electron, Scanning; D016062:Porosity; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012996:Solutions
chemical_list: D002021:Buffers; D007477:Ions; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D002606:Charcoal; D017665:Hydroxyl Radical