title: Enhanced Power Generation of Oxygen-Reducing Biocathode with an Alternating Hydrophobic and Hydrophilic Surface.
abstract: Most oxygen-reducing biocathodes for microbial electrochemical systems (MESs) require energy-intensive aeration of the catholyte, which negates the energy-saving benefits of MESs. To avoid aeration and enhance oxygen-utilization efficiency, columnar activated carbon with half of its surface coated by polytetrafluoroethylene (PTFE-coated CAC) was fabricated as biocathode material, and its performance was investigated using a tide-type biocathode MES (TBMES). The TBMES with PTFE-coated biocathode achieved a maximum power density of 8.2 ± 0.8 W m-3, which was 39% higher than that of the untreated control (CAC biocathode). The PTFE-coated biocathode was able to store a cumulative total charge (Qm) of (10.8 ± 0.2) × 104C m-3during one charge-discharge cycle, whereas the Qmof CAC biocathode was only (6.9 ± 0.1) × 104C m-3, demonstrating that the oxygen entrapment capability of PTFE-coated biocathode was 54 ± 3.8% higher than that of the control. Internal resistance analysis under both oxygen sufficient and reoxygenation conditions suggested the oxygen entrapped by this surface-hydrophobic biocathode was basically sufficient for cathodic oxygen reduction reaction. The slight difference in cathodic microbial communities of the two biocathodes further indicated that the higher accessibility of oxygen due to the hydrophobic surface was the primary cause for the better performance of the PTFE-coated biocathode, while the higher biocatalytic activity of the cathodic biofilm was a minor factor.
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology , No 73 Huanghe Road, Nangang District, Harbin 150090, China.
authors: Haiman
authors: H
authors: Wang
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology , No 73 Huanghe Road, Nangang District, Harbin 150090, China.
authors: Jia
authors: J
authors: Liu
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology , No 73 Huanghe Road, Nangang District, Harbin 150090, China.
authors: Weihua
authors: W
authors: He
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology , No 73 Huanghe Road, Nangang District, Harbin 150090, China.|School of Life Science and Technology, Harbin Institute of Technology , No. 2 Yikuang Street, Nangang District, Harbin 150080, China.
authors: Youpeng
authors: Y
authors: Qu
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology , No 73 Huanghe Road, Nangang District, Harbin 150090, China.
authors: Da
authors: D
authors: Li
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology , No 73 Huanghe Road, Nangang District, Harbin 150090, China.
authors: Qing
authors: Q
authors: Jiang
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology , No 73 Huanghe Road, Nangang District, Harbin 150090, China.
authors: Yujie
authors: Y
authors: Feng
keywords: air affinity; air-entrapped biocathode; columnar activated carbon; hydrophobic surface; microbial electrochemical system