Abstract:

Synthetic dyes are used by printing and dyeing industry in most cases， with azo dyes accounting for about 80% of them. As one of the representative azo dyes， reactive black 5（RB5） is commonly used for dyeing cotton， other cellulosic fibers， wool and nylon. Azo dye wastewater contains a large amount of difficultly biodegradable organic matter. In addition to decolorization， degradation and mineralization of dyes and intermediates in azo dye wastewater， and reduction of toxicity are also objectives. The toxicity of biofilm reactor effluent was monitored for the characteristics that the products of RB5 after microbial decolorization were difficult to be degraded. And the results showed that effluent had residual toxicity. An electrochemical device with titanium-based oxide coating as the anode material was used to treat wastewater containing RB5 decolorization products. Under the conditions of sodium chloride concentration of 0.05 mol/L， initial pH of 7， current density of 60 mA/cm² and electrolysis time of 4 h， the COD removal rate of effluent could reach 90.23%， and the effluent quality met the requirements of discharge standard.

Key words: reactive black 5, azo dye, decoloration, electrochemical oxidation

摘要：

印染行业使用的染料多为化学合成染料，其中以偶氮发色团为基础的合成染料约占80%。作为具有代表性的偶氮活性染料之一，活性黑5（RB5）常用于棉花、其他纤维素纤维、羊毛和尼龙的染色。偶氮染料废水中含有大量难降解的有机物。除脱色外，对废水中的染料与中间产物进行降解矿化、降低毒性，也是偶氮染料废水的处理目标。针对RB5经微生物脱色后的产物难以生化降解的特点，对生物膜反应器出水毒性进行监测，结果表明RB5废水经微生物脱色后仍有残留毒性。采用钛基金属氧化物涂层为阳极材料的电化学装置对含RB5脱色产物的废水进行处理，在电解质氯化钠浓度为0.05 mol/L、初始pH为7、电流密度为60 mA/cm²、电解时间为4 h的条件下，出水的COD去除率可达到90.23%，出水水质达到排放标准要求。

关键词: 活性黑5, 偶氮染料, 脱色, 电化学氧化

CLC Number: 

• X703