共基质促进生物电催化还原硝基苯研究

Enhanced efficiency and selectivity of bio-electrocatalyzed nitrobenzene reduction by employing co-substrate

摘要:

为提高生物催化电解系统(BCES)定向还原硝基苯的能力,促进难降解有机物的快速脱毒和进一步生物转化,采用葡萄糖作为共基质,探讨其质量浓度对于生物阴极催化性能和硝基苯还原效率的影响．结果表明,共基质能够作为额外电子供体加速硝基苯向苯胺的定向转化,同时提高了生物阴极催化硝基苯还原的活性,表现为硝基苯还原峰电位正移70 mV．为避免过度增加废水中的COD,共基质的引入量控制在200 mg·L-1较为适宜,此时苯胺的生成率在各外加电压条件下(0.15～0.5 V)均超过97 ％,硝基苯还原一级动力学常数较无共基质存在时平均提高(52 ±6) ％．

Abstract:

To improve the selective reduction of nitrobenzene to aniline in biocatalyzed electrolysis system (BCES), glucose, as the co-substrate, was employed into the biocathode. The enhancement of nitrobenzene reduction efficiency and selectivity by adding co-substrate was observed. Cyclic voltammetry revealed nitrobenzene reduction peak was positively shifted by 70 mV with the present of co-substrate, indicating the enhanced performance was caused by not only the extra electrons donated by glucose but also the improvement of bioelectrocatalytic activity. To avoid the excess increase of COD in wastewater, the suggested concentration of co-substrate was 200 mg·L-1, which resulted in aniline formation efficiency over 97 ％ at all tested applied voltages (0.15-0.25 V), and increased the apparent first-order kinetic constant by (52 ± 6)％ compared to that without co-substrate.