Perey Jennie R, Chiu Pei C, Huang Chin-Pao, Cha Daniel K
Department of Civil and Environmental Engineering, University of Delaware, Newark 19716, USA.
Water Environ Res. 2002 May-Jun;74(3):221-5. doi: 10.2175/106143002x139938.
Azo dyes are a group of chemicals that are largely resistant to aerobic biodegradation and persist in wastewater treatment processes. This study proposed that zero-valent iron can be used to reduce the azo bond, cleaving the dye molecule into products that are more amenable to mineralization by bacteria in biological treatment processes such as activated sludge. Batch anaerobic reduction experiments were performed using two azo dyes, orange G and orange II, to determine reaction kinetics and to identify reduction products. Iron-treated dye solutions were subjected to batch biodegradation tests and respirometric analyses to screen for enhanced biodegradability over parent dyes. Results indicate that treatment of orange G and orange II with scrap iron produces aniline and sulfanilic acid as significant products that are degraded by an acclimated culture within 24 hours. Respirometric data illustrated that iron-treated dye solutions exert a significantly higher biochemical oxygen demand than the solutions containing orange G and orange II, demonstrating that recalcitrant azo dyes can be aerobically biodegraded after iron pretreatment.
偶氮染料是一类化学物质，它们在很大程度上抗需氧生物降解，并在废水处理过程中持续存在。本研究提出，零价铁可用于还原偶氮键，将染料分子裂解成更易于在生物处理过程（如活性污泥）中被细菌矿化的产物。使用两种偶氮染料橙黄G和橙黄II进行了间歇厌氧还原实验，以确定反应动力学并识别还原产物。对经铁处理的染料溶液进行间歇生物降解试验和呼吸测量分析，以筛选出比母体染料具有更高生物降解性的情况。结果表明，用废铁处理橙黄G和橙黄II会产生苯胺和磺胺酸作为主要产物，这些产物在24小时内可被驯化培养物降解。呼吸测量数据表明，经铁处理的染料溶液的生化需氧量明显高于含有橙黄G和橙黄II的溶液，这表明难降解的偶氮染料在铁预处理后可进行需氧生物降解。
