生物电催化方法处理三氯乙酸的研究

Reductive Dechlorination of Trichloroacetic Acid by Bioelectrochemically Catalytic Method

利用吸附法将血红蛋白(Hb)固定在碳纳米管修饰电极表面,研究了Hb在碳纳米管修饰电极的直接电化学行为.固载Hb碳纳米管修饰电极在pH=7·0的PBS缓冲溶液中于-0·300V(vsSCE)处有一对相当可逆的循环伏安还原氧化峰,为Hb血红素辅基Fe(Ⅲ)/Fe(Ⅱ)电对的特征峰.利用循环伏安法和恒电位电解法研究了固载Hb的碳纳米管修饰电极对有机氯模型污染物三氯乙酸的电催化还原脱氯,并通过鉴定中间产物探讨了其催化还原机理.结果表明,固载Hb的碳纳米管修饰电极对三氯乙酸的还原具有很高的催化活性,三氯乙酸是按照三氯乙酸→二氯乙酸→一氯乙酸→乙酸的途径分布还原脱氯.将固载Hb的碳纳米管修饰电极组装成三维填充床电解反应器,进行了三氯乙酸连续流动电解还原的初步研究.-0·6V(vs.SCE)电解180min,三氯乙酸去除率为40·13%.

Direct electrochemical behaviors of hemoglobin (Hb) immobilized on carbon nanotube (CNT) modified carbon paste electrode with adsorption were investigated. Cyclic voltammetry of Hb-CNT-modified electrode showed a pair of well-defined and nearly reversible peaks for HbhemeFe(Ⅲ)/Fe(Ⅱ) redox couple in pH=7 PBS buffers. The electrocatalytic behaviors of Hb-CNT-modified electrode for the reductive dechlorination of trichloroacetic acid (TCA) were studied by cyclic voltammmetry and fixed-potential electrolysis technique, and the reductive mechanism of TCA was discussed by analysis of reduction products. The results showed that Hb-CNT-modified electrode possessed good electro-catalytic activity for reduction of TCA and the dechlorination of TCA was stepwise, following the pathway of trichloroacetic→dichloroacetic→monochloroacetic→acetic. The dechlorination of TCA in waster water was investigated using a two-compartment flow reactor with working electrode compartment packed with Hb-CNT-modified graphite electrode. The conversion of TCA was 40.13% with electrolysis for 180 min at -0.60V (vs. SCE).