微生物燃料电池化学阴极与生物阴极处理含铬废水

采用双室微生物燃料电池(MFC)反应器,考察了不同初始Cr(VI)浓度下化学阴极与生物阴极MFC的产电及Cr(VI)去除情况。结果表明,在各Cr(VI)浓度梯度 (20、28、32、36、40和44 mg/L)下生物阴极MFC的产电及Cr(VI)去除性能均较化学阴极MFC更优,生物阴极最大输出电压为180.1 mV,是化学阴极的1.3倍。随着初始Cr(VI)浓度的递增,两者对Cr(VI)去除的差异越明显,最终在Cr(VI)浓度为44 mg/L时,生物阴极MFC的Cr(VI)去除率为66.4%,较化学阴极提高了55.1%。进一步由循环伏安扫描、电镜扫描及X-射线能谱分析证实生物阴极MFC较化学阴极MFC产电及去铬性能优越的主要原因除了生物阴极电极上电化学活性微生物的催化作用外,Cr(VI)还原产生的不导电Cr(III)沉积物在其电极上附着较少也是一个关键因素,该Cr(III)沉积物中含有Cr2O3。

Treatment of chromium (VI) wastewater with abiotic cathode and biocathode microbial fuel cells

The output voltage and reduction of hexavalent chromium (Cr(VI)) of abiotic cathode and biocathode microbial fuel cells (MFCs) with different initial Cr(VI) concentrations were investigated in dual-chambered microbial fuel cells.The results demonstrated that the output voltage and Cr(VI) removal ratio of biocathode MFC were higher than abiotic cathode MFC with different initial Cr(VI) concentrations (20,28,32,36,40,44 mg/L).The maximum output voltage of biocathode MFC was 180.1 mV,which was 1.3 times of abiotic cathode MFC.With the gradual increase of initial Cr(VI) concentration,the difference of Cr(VI) removal between abiotic cathode and biocathode MFC was enhanced.Eventually,the Cr(VI) removal of biocathode MFC was 66.4% which was 55.1% higher compared with abiotic cathode MFC at initial Cr(VI) concentration of 44 mg/L.Except for the catalysis of electrochemically active bacteria on the biocathode,a smaller amount of non-conductive Cr(III) precipitation containing Cr2O3 reduced from Cr(VI) and attached on the surface of electrode was also a key factor for the superiority of biocathode MFC in output voltage and Cr(VI) removal aspects which was further confirmed by CV,SEM and EDX analysis.