Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Chemosphere. 2018 Jan;191:494-502. doi: 10.1016/j.chemosphere.2017.10.086. Epub 2017 Oct 15.
In this study, the double-edge role of permanganate in sulfamethoxazole (SMX) photodegradation with a recyclable catalyst was revealed for the first time. The role of the catalyst under different UV wavelength, the role of permanganate in the treatment process, the effects of permanganate dosage and solution pH on the removal efficiency were investigated. Moreover, the transformation products, TOC reduction and the toxicity of the treated final product to Chlorella vulgaris and Artemia salina were determined. Sole permanganate showed no effect in SMX degradation, while its introduction to the photocatalytic process doubled the reaction rate at the optimal dosage. It is interesting to find that the reaction rate showed a fluctuation trend in terms of permanganate dosage due to the summation of positive effect of permanganate oxidation and the negative effect of the formed MnO at the surface of the catalyst, as well as the light attenuation due to overdosed permanganate. The determined intermediates, the higher inorganic ions release and TOC reduction provided a clue on a higher mineralization compared to SMX degradation in the same process without permanganate. Permanganate above 1 μM may pose a threat to the algae growth, therefore a good monitoring and control of residual permanganate dosage should be incorporated into the process design. A good toxicity reduction to A. salina was observed in the treated effluent; a longer detention is suggested for the complete removal of toxicity.
在这项研究中，首次揭示了高锰酸盐在可回收催化剂存在下磺胺甲恶唑（SMX）光降解中的双重作用。研究了在不同 UV 波长下催化剂的作用、高锰酸盐在处理过程中的作用、高锰酸盐用量和溶液 pH 值对去除效率的影响。此外，还测定了转化产物、TOC 去除率以及处理终产物对小球藻和卤虫的毒性。单独的高锰酸盐对 SMX 降解没有影响，而将其引入光催化过程在最佳剂量下使反应速率提高了一倍。有趣的是，由于高锰酸盐氧化的正效应和催化剂表面形成的 MnO 的负效应以及由于高锰酸盐过量导致的光衰减的综合作用，高锰酸盐用量对反应速率表现出波动趋势。确定的中间产物、更高的无机离子释放和 TOC 去除提供了一个线索，表明与同一过程中没有高锰酸盐的 SMX 降解相比，具有更高的矿化程度。超过 1μM 的高锰酸盐可能对藻类生长构成威胁，因此应在工艺设计中纳入对残留高锰酸盐剂量的良好监测和控制。处理后的流出物对卤虫的毒性降低效果良好；建议延长停留时间以完全去除毒性。
