湿地基质及阴极面积对人工湿地型微生物燃料电池去除偶氮染料同步产电的影响

本研究采用人工湿地型微生物燃料电池处理偶氮染料X-3B,实现降解偶氮染料同步产电的效果.为了构建性能最优的人工湿地型微生物燃料电池(CW-MFC)系统,本研究主要从湿地基质和阴极面积两个方面研究系统构型对去除X-3B同步产电的影响,提高系统性能.研究表明以粒径10 mm、孔隙率30%的小石子作为湿地基质构造的CW-MFC系统微生物生物量最大,去除X-3B效果最好,脱色率高达92.70%,但其产电性能最差.较小的粒径和孔隙率使底层微生物生物量增加,促进X-3B的去除,但随着湿地基质粒径和孔隙率的减小,导致阴阳极营养物质不足,系统传质阻力增加,抑制了系统产电性能.X-3B的去除效果随着阴极面积的增加而提高直到阴极面积为594 cm~2时取得最大脱色率99.41%.当阴极面积继续增加时,CW-MFC系统产电性能上升趋势趋于平缓,X-3B去除效果呈现下降趋势,这是因为阴极反应过快导致更多的阳极电子输送到阴极用于产生电流,与X-3B发生反应的电子减少,阳极成为提高CW-MFC系统性能的限制因素.

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 cm². 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.