微生物电化学体系中金红石可见光还原降解偶氮染料的实验研究  

Experimental researches on photoreduction of azo dyes in the rutile-cathode bioelectrochemical system

作　　者：丁竑瑞[1] 李艳[1] 鲁安怀[1] 权超[1] 王鑫[1] 颜云花[1] 曾翠平[1] 王长秋[1] 

机构地区：[1]造山带与地壳演化教育部重点实验室,北京大学地球与空间科学学院,北京100871

出　　处：《岩石矿物学杂志》2009年第6期541-546,共6页Acta Petrologica et Mineralogica

基　　金：国家重点基础研究发展计划资助项目(2007CB815602)

摘　　要：利用双室微生物电化学装置对微生物和半导体矿物协同作用下偶氮类染料废水的还原脱色降解进行了系统的实验研究。不同光照条件及不同阴极电极材料的对比实验结果显示,偶氮染料甲基橙(MO)可作为终端电子受体直接从固体电极上获得电子被还原脱色;各对比实验中,在微生物催化与半导体矿物光催化协同作用条件下,MO还原脱色效率最高。电化学交流阻抗谱(EIS)的拟合结果显示金红石涂布阴极电极光照下极化内阻(Rp)为443.4Ω,较无光条件下的1378Ω显著降低,证明光照下金红石阴极的电子转移过程受其光催化作用的驱动。不同初始浓度下MO的生物-半导体催化还原反应符合准一级动力学模型,其反应速率随MO初始浓度降低而增加。通过对脱色产物的进一步分析,推测该实验中MO的还原脱色反应机制为:阳极初始电子供体在微生物的催化作用下将电子通过阳极电极和外电路传递给阴极半导体矿物电极,进而在半导体矿物的光催化作用下通过光生电子还原终端电子受体MO,使MO中的偶氮键断裂,生成无色的联氨类衍生物。The reductive decolorization of azo dye wastewater was investigated by using a dual-chambered bioelectrochemical cell equipped with different cathode materials （graphite and rutile-coated graphite）. The experimental data show the feasibility of electricity generation by utilizing the model azo dye of methyl orange （MO） as the cathodic electron acceptor along with the color removal. Compared with MO reduction in traditional microbial fuel cell （MFC）,an increase of the efficiency for MO reduction as well as the electricity production was successfully achieved in the irradiated rutile-cathode system. Quantification of the internal resistance by fitting the electrochemical impedance spectra （EIS） data to an equivalent circuit showed that the polarization resistance （Rp） of rutile-cathode significantly decreased from 1 378 Ω （dark control） to 443.4 （light control） Ω. The results demonstrate that the cathodic electron transfer process in the irradiated rutile-cathode system is driven by the photocatalysis of rutile. The photoreduction of MO at different initial concentrations obeys the pseudo-first-order kinetics,and the reaction constant increases with the decrease of the initial concentration of the dye. Based on an analysis of decolorization products,the authors put forward a possible cathodic reaction mechanism for the photoreductive decolorization of MO,i.e.,the azo bond of MO is cleaved by photoelectrons at the irradiated rutile-cathode,resulting in the formation of colorless hydrazine derivative.

关 键 词：生物电化学 偶氮染料 金红石 光催化还原 

分 类 号：P578.47[天文地球—矿物学] P579[天文地球—地质学]