Photocatalysis assisted by peroxymonosulfate and persulfate for benzotriazole degradation: effect of pH on sulfate and hydroxyl radicals
Photocatalysis assisted by peroxymonosulfate and persulfate for benzotriazole degradation: effect of pH on sulfate and hydroxyl radicals
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DOI：
10.2166/wst.2015.437
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发表时间：
2015-12-01
影响因子：
2.7
通讯作者：
Moradi, Mahsa
中科院分区：
文献类型：
--
作者：
Ahmadi, Mehdi;Ghanbari, Farshid;Moradi, Mahsa
最近，人们进行了一些值得注意的尝试，以消除水资源中新出现的污染物。苯并三氮唑（BTA）作为一种新的污染物，在水环境和水资源中被广泛检测到。在TiO 2/UV体系中添加过硫酸盐（PMS）和过硫酸盐（PS）作为电子受体，克服了光催化降解BTA过程中电子和空穴的复合，提高了降解效率。UV/TiO 2/PMS、UV/TiO 2/PS和UV/TiO 2的反应速率常数分别为0.0217min（-1）、0.0152min（-1）和0.0052min（-1）。结果表明，pH值对UV/TiO 2/PMS体系有显著影响，而对UV/TiO 2/PS体系影响不大。使用醇的清除实验表明，在酸性pH值，在这两个系统中，占主导地位的氧化剂是硫酸根。在碱性和中性条件下，羟基自由基对BTA降解的贡献增强，尤其是在UV/TiO 2/PMS体系中。此外，其他清除实验表明，自由基的反应发生在催化剂表面和溶液中。矿化结果表明，PMS和PS显著提高了化学需氧量和总有机碳的去除效率。一般来说，PMS的存在下，在反硝化过程中有一个更好的性能相比，PS在BTA的去除和矿化。
Recently, notable attempts have been devoted to removing emerging pollutants from water resources. Benzotriazole (BTA) as an emerging pollutant has widely been detected in the aquatic environment and water resources. In the current work, peroxymonosulfate (PMS) and persulfate (PS) were added to a TiO2/UV system for BTA degradation, as electron acceptors to overcome recombination of hole and electron. Additions of PMS and PS to the photocatalysis process considerably increased removal efficiency. The rate constants of UV/TiO2/PMS, UV/TiO2/PS and UV/TiO2 were 0.0217 min(-1), 0.0152 min(-1) and 0.0052 min(-1) respectively. The results showed that pH significantly affected the UV/TiO2/PMS system while it marginally affected UV/TiO2/PS. Scavenging experiments using alcohols indicated that in acidic pH, the dominant oxidant was sulfate radical in both systems. The contribution of hydroxyl radical in BTA degradation was boosted at alkaline and neutral conditions especially in the UV/TiO2/PMS system. Moreover, other scavenging experiments implied that reaction of radicals occurred at both the catalyst surface and in solution. The mineralization results showed that PMS and PS significantly increased chemical oxygen demand and total organic carbon removal efficiencies. In general, presence of PMS in the photocatalysis process had a better performance compared to PS in terms of BTA removal and mineralization.