Encinas-Yocupicio A A, Razo-Flores E, Sánchez-Diaz F, dos Santos A B, Field J A, Cervantes F J
Departamento de Ciencias del Agua y del Medio Ambiente, Instituto Tecnológico de Sonora, Mexico.
Water Sci Technol. 2006;54(2):165-70. doi: 10.2166/wst.2006.500.
The catalytic effects of redox mediators, with distinct standard redox potentials (E'0), were evaluated on the first-order rate constant of decolorization (Kd) of recalcitrant azo dyes by an anaerobic granular sludge. The dyes studied included mono-azo (Reactive Orange 14, RO14), di-azo (Direct Blue 53, DB53), and tri-azo (Direct Blue 71, DB71) compounds. Toxicity and auto-catalytic aspects seemed to play a role in determining the rate of decolorization. Addition of riboflavin, anthraquinone-2,6-disulphonate (AQDS) or lawsone as a redox mediator, increased the Kd value for all dyes studied, although their impact varied in every case. Kd values were increased from 1.1-fold up to 3.8-fold depending on the redox mediator applied. Moreover, catalysts with moderately similar E'0 value caused distinct stimulation on the rate of decolorization. These results should be considered for selecting the proper redox mediator to be applied during the anaerobic treatment of textile wastewaters and effluents containing electron-withdrawing pollutants, such as nitro-aromatic and polychlorinated compounds.
研究了具有不同标准氧化还原电位（E'0）的氧化还原介质对厌氧颗粒污泥对难降解偶氮染料脱色一级速率常数（Kd）的催化作用。所研究的染料包括单偶氮（活性橙14，RO14）、双偶氮（直接蓝53，DB53）和三偶氮（直接蓝71，DB71）化合物。毒性和自催化方面似乎在决定脱色速率中起作用。添加核黄素、蒽醌-2,6-二磺酸盐（AQDS）或胡桃醌作为氧化还原介质，增加了所有研究染料的Kd值，尽管它们在每种情况下的影响各不相同。根据所应用的氧化还原介质，Kd值增加了1.1倍至3.8倍。此外，具有适度相似E'0值的催化剂对脱色速率产生了明显的刺激作用。在选择合适的氧化还原介质用于纺织废水和含有吸电子污染物（如硝基芳烃和多氯化合物）的废水的厌氧处理时，应考虑这些结果。
