Sequential decolorization of azo dye and mineralization of decolorization liquid coupled with bioelectricity generation using a pH self-neutralized photobioelectrochemical system operated with polarity reversion.
A novel photobioelectrochemical system (PBES) was developed by acclimating algal-bacterial biofilm in both anode and cathode using Chlorella vulgaris and indigenous wastewater bacteria as inoculums. The PBES was operated in polarity reversion mode depend on dark/light alternate reaction to achieve simultaneous pH self-neutralization, azo dye degradation (Congo red) and bioelectricity generation. The anodic accumulated acidity and cathodic accumulated alkalinity were self-neutralized after polarity reversion and hence eliminate the membrane pH gradient. The Congo red was first decolored in the dark anode and the resultant decolorization liquid was subsequently mineralized after the dark anode changing to the photo-biocathode. The presence of C. vulgaris significantly enhanced the two-stage degradation of Congo red, with 93% increases in decolorization rates and 8% increases in mineralization compared to the algae-free BES. The PBES continuously generated stable voltage output over four months under repeatedly reversion of polarity. The maximum power density produced before and after polarity reversion was 78 and 61 mW/m(2), respectively. The synergy between C. vulgaris and mixed bacteria was responsible for the successful operation of the PBES which can be potentially applied to treat wastewater containing azo dye with benefits of enhanced azo dye degradation, high net power output and buffer minimization.
Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration area, College of Environment and Energy, South China University of Technology, Guangzhou 510006, China; School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
Jian
J
Sun
Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration area, College of Environment and Energy, South China University of Technology, Guangzhou 510006, China; State Key Lab of Pulp and Paper Engineering, College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640, China. Electronic address: ppyyhu@scut.edu.cn.
Yongyou
Y
Hu
Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration area, College of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
Wanjun
W
Li
School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
Yaping
Y
Zhang
Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration area, College of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
Jie
J
Chen
Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration area, College of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
Feng
F
Deng
D001391:Azo Compounds / Q000737:chemistry*; D001419:Bacteria / Q000378:metabolism; D001674:Bioelectric Energy Sources; D048408:Chlorella vulgaris / Q000737:chemistry / Q000378:metabolism; D004396:Coloring Agents / Q000737:chemistry*; D003224:Congo Red; D004563:Electrochemistry; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D010777:Photochemistry
D001391:Azo Compounds; D004396:Coloring Agents; D003224:Congo Red
Algae–bacteria synergism; Azo dye treatment; Electricity generation; Photobioelectrochemical system; Polarity reversion; pH self-neutralization