Environmental Biotechnology Department, Silesian University of Technology, Akademicka 2, 44-100, Gliwice, Poland.
Water Sci Technol. 2009;60(10):2555-62. doi: 10.2166/wst.2009.651.
Improvement of sulfamethoxazole (4-amino-N-(5-methylisoxazol-3-yl)-benzenesulfonamide-SMX) biodegradability using a modified Fenton's reaction has been studied. The modification consists of replacing hydrogen peroxide with atmospheric air and adding copper sulphate as a reaction promoter. Two series of experiments were carried out. The first (Series 1) was conducted using only the catalysts with aeration. In the second series (Series 2), cycles of UVA radiation and aeration were used. During UVA radiation, the removal of sulfamethoxazole proceeds less rapidly than in only aerated solution. After 1.5 h of these two processes, the SMX degradation was 23% in Series 2 and 59% in Series 1. The opposite trend was observed for mineralization and the removal of DOC was about 5% higher in Series 2 than in Series 1. The FTIR spectra of the extracts of reaction products yielded by four organic solvents of varying polarity revealed a wide diversity of functional groups in the post-reaction mixture in comparison to the extracts from sulfamethoxazole solution. Based on FTIR analysis, several oxidation products of sulfamethoxazole are proposed. Apparently, hydroxyl radicals initially attack sulphonamide bonds, resulting in the formation of sulfanilic acid and 3-amino-5-methylisoxazole. Irrespective of the reference organism used in toxicity tests, the post-reaction mixture in the Series 2 was more toxic than the post-reaction mixture in Series 1. In contrast, the biodegradability calculated as BOD(5)/DOC ratio, was higher for post-reaction mixture 2 and amounted to 0.43.
使用改良芬顿反应提高磺胺甲恶唑（4-氨基-N-（5-甲基异恶唑-3-基）苯磺酰胺-SMX）的可生物降解性的研究。该改良包括用大气中的氧气代替过氧化氢，并添加硫酸铜作为反应促进剂。进行了两组实验。第一组（系列 1）仅使用曝气催化剂进行实验。在第二组（系列 2）中，使用 UVA 辐射和曝气循环。在 UVA 辐射期间，磺胺甲恶唑的去除速度比仅在曝气溶液中要慢。在这两个过程进行 1.5 小时后，磺胺甲恶唑在系列 2 中的降解率为 23%，在系列 1 中的降解率为 59%。对于矿化，观察到相反的趋势，在系列 2 中的去除率比系列 1 中高约 5%。四种不同极性有机溶剂的反应产物提取物的 FTIR 光谱显示，与磺胺甲恶唑溶液的提取物相比，反应后混合物中存在广泛的官能团多样性。基于 FTIR 分析，提出了磺胺甲恶唑的几种氧化产物。显然，羟基自由基首先攻击磺酰胺键，导致磺胺和 3-氨基-5-甲基异恶唑的形成。无论在毒性测试中使用何种参考生物，系列 2 中的反应后混合物比系列 1 中的反应后混合物毒性更大。相比之下，反应后混合物 2 的生物降解性（以 BOD(5)/DOC 比计算）更高，达到 0.43。
