van der Zee F P, Lettinga G, Field J A
Department of Agrotechnology and Food Sciences, Wageningen University, The Netherlands.
Chemosphere. 2001 Aug;44(5):1169-76. doi: 10.1016/s0045-6535(00)00270-8.
The decolourisation of 20 selected azo dyes by granular sludge from an upward-flow anaerobic sludge bed (UASB) reactor was assayed. Complete reduction was found for all azo dyes tested, generally yielding colourless products. The reactions followed first-order kinetics and reaction rates varied greatly between dyes: half-life times ranged from 1 to about 100 h. The slowest reaction rates were found for reactive dyes with a triazine reactive group. There was no correlation between a dye's half-life time and its molecular weight, indicating that cell penetration was probably not an important factor. Since granular sludge contains sulphide, eight dyes were also monitored for direct chemical decolourisation by sulphide. All these dyes were reduced chemically albeit at slower rates than in the presence of sludge at comparable sulphide levels. Increasing sulphide concentrations, even when present in huge excess, stimulated the azo reduction rate. The results indicate that granular sludge can decolourise a broad spectrum of azo dye structures due to non-specific extracellular reactions. Reducing agents (e.g., sulphide) in sludge play an important role. The presence of anaerobic biomass is probably beneficial for maintaining the pools of these reduced compounds.
对来自上流式厌氧污泥床（UASB）反应器的颗粒污泥对20种选定偶氮染料的脱色情况进行了测定。结果发现，所有测试的偶氮染料都能完全还原，通常生成无色产物。反应符合一级动力学，不同染料之间的反应速率差异很大：半衰期从1小时到约100小时不等。含三嗪活性基团的活性染料反应速率最慢。染料的半衰期与其分子量之间没有相关性，这表明细胞渗透可能不是一个重要因素。由于颗粒污泥含有硫化物，还监测了8种染料被硫化物直接化学脱色的情况。所有这些染料都能被化学还原，尽管速率比在可比硫化物水平下存在污泥时要慢。即使硫化物浓度大量过量，增加其浓度也会刺激偶氮还原速率。结果表明，由于非特异性细胞外反应，颗粒污泥能使广泛的偶氮染料结构脱色。污泥中的还原剂（如硫化物）起着重要作用。厌氧生物质的存在可能有利于维持这些还原化合物的总量。
