剩余污泥燃料电池处理含铬废水的效能及机理

采用剩余污泥为阳极底物,六价铬为阴极电子受体,构建双室微生物燃料电池(MFC).MFC启动成功后,考察阳极室污泥初始浓度和阴极室六价铬初始浓度对MFC产电性能及六价铬还原速率的影响.较高的污泥浓度(8~12g/L)对六价铬的还原速率影响均较小,且去除率均可达99%以上.污泥浓度为10g/L的MFC具有较高的产电性能,内阻为108Ω,最大功率密度输出为3621mW/m3.阴极室较高的Cr(VI)初始浓度可维持较长时间的高输出电压,但对阳极污泥降解并无明显影响.XPS测试结果表明,阴极Cr(VI)的还原产物为Cr(III),因电场作用被吸附在电极片上,使得阴极溶液中的总铬浓度降低.研究表明,剩余污泥为底物的微生物燃料电池可以在产电的同时实现剩余污泥的资源化及电镀废水的无害化.

Efficacy and mechanism of microbial fuel cell treating Cr(VI)-containing wastewater with excess sludge as substrate

The double-chamber microbial fuel cell systems (MFCs) were constructed with excess sludge as anodic substrate and potassium dichromate as catholyte. The effects of the initial concentrations of both excess sludge and Cr (VI) on MFC systems were investigated. According to the results, the MFC systems with sludge concentrations of 8~12 g/L presented almost the same degradation rates of Cr (VI), and a high removal efficiency of 99% was achieved. When the initial concentration of excess sludge was 10 g/L, the MFC system arrived at the best performance with an inner resistance of 108 Ω and maximum power density of 3621 mW/m3. A higher initial concentration of Cr (VI) could keep a longer period of stable high output voltage, but had no obvious effect on the sludge degradation in the anode chamber. Furthermore, the reduction products adhered on the surface of carbon cloth in the cathode chamber were demonstrated to be Cr (III), which led to decrease of total chromium in cathode solution. The MFC system with fuel recovery from excess sludge could be a promising technology, which is able to simultaneously address energy issues and environmental concerns associated with excess sludge and electroplating wastewater.