So C M, Cheng M Y, Yu J C, Wong P K
Department of Biology, The Chinese University of Hong Kong, Shatin, NT.
Chemosphere. 2002 Feb;46(6):905-12. doi: 10.1016/s0045-6535(01)00153-9.
The photocatalytic oxidation (PCO) of a monoazo dye Procion Red MX-5B under various physico-chemical conditions was investigated. Degradation of the dye by PCO was enhanced by augmentation in UV intensity, titanium dioxide and hydrogen peroxide concentrations but was inhibited by increase in initial dye concentration. The PCO process was affected by pH in a peculiar way. In the presence of 100 mg/l of TiO2 and the absence of H2O2, the highest reaction rate was observed when the initial pH was 10. With 500 mg/l of TiO2 and 10 mM of H2O2, the reaction was the fastest at initial pH of 3-5. The optimal conditions for the degradation of the dye, at an UV intensity of 17 mW/cm2, were determined to be: TiO2 concentration, 500 mg/l; initial H2O2 concentration, 10 mM; initial pH, 5.0. Monitoring of TOC loss showed that the dye was mineralized by 90% within 80 min under these conditions. Nevertheless, the persistence of a low level of TOC indicated that mineralization was not complete and dead-end product(s) which was (were) resistant to PCO might have accumulated.
研究了在各种物理化学条件下单偶氮染料普施安红MX - 5B的光催化氧化（PCO）过程。紫外线强度、二氧化钛和过氧化氢浓度的增加会促进PCO对该染料的降解，但初始染料浓度的增加会抑制降解。PCO过程受pH的影响较为特殊。在存在100 mg/l二氧化钛且不存在过氧化氢的情况下，当初始pH为10时观察到最高反应速率。在存在500 mg/l二氧化钛和10 mM过氧化氢的情况下，初始pH为3 - 5时反应最快。在紫外线强度为17 mW/cm²时，确定该染料降解的最佳条件为：二氧化钛浓度500 mg/l；初始过氧化氢浓度10 mM；初始pH 5.0。对总有机碳（TOC）损失的监测表明，在这些条件下，该染料在80分钟内有90%被矿化。然而，低水平TOC的持续存在表明矿化并不完全，可能积累了对PCO有抗性的终产物。
