[Effects of Microbial Fuel Cell Coupled Constructed Wetland with Different Support Matrix and Cathode Areas on the Degradation of Azo Dye and Electricity Production].

In this study, microbial fuel cell coupled constructed wetland (CW-MFC) was constructed for azo dye reactive brilliant red X-3B degradation and electricity production. The effects of support matrix and cathode areas on the degradation of X-3B and the electricity production of CW-MFC were investigated in this work to improve the performance of CW-MFC. The highest decolorization efficiency was 92.70% and was obtained when the CW-MFC was constructed with support matrix S3 with particle size of 10 mm and porosity of 30%. Small particle size increased the microbial biomass of the bottom layer of CW-MFC, which would promote the decolorization of X-3B in the bottom layer. However, it may cause the lack of nutrition in electrode layer and the increase in resistance of mass transfer, which would lead to the decline of electricity production. The decolorization efficiency and the power density of CW-MFC increased concomitantly with the increase of cathode areas, and the CW-MFC got the highest decolorization efficiency of 99.41% when the cathode area was 594 cm. The electricity production performance became stable when the cathode area continued to increase, while the decolorization efficiency declined. This may be attributed to that more electrons were transferred to the cathode to produce current instead of used in degradation of X-3B.