Department of Environmental and Safety Engineering, Ming Chi University of Technology, Taishan, New Taipei City 24301, Taiwan.
Chronic Disease and Health Promotion Research Center, Chang Gung University of Science and Technology, Chiayi 61363, Taiwan.
Int J Environ Res Public Health. 2020 Jun 23;17(12):4513. doi: 10.3390/ijerph17124513.
Amine-containing pharmaceuticals are the most often detected pharmaceuticals in wastewater and ambient aquatic environments. They can usually be degraded by manganese oxide (MnO), which is a common natural oxidant in soils. Surfactants often coexist with pharmaceuticals in wastewater. Some amine-containing pharmaceuticals, such as diclofenac (DIC), are acidic and are thus ionic compounds in neutral conditions. These compounds, therefore, have similar properties to surfactants. Surfactants, thus, may influence the adsorption and degradation processes of DIC by MnO. The effect of the type of surfactant on the degradation of DIC by MnO was investigated in this study with the addition of two common biodegradable surfactants (cetyltrimethyl-ammonium bromide (CTAB) and sodium dodecylsulfate (SDS)). The results indicated that the cationic surfactant (CTAB) significantly increased the degradation rate in neutral and alkaline conditions. On the other hand, the anionic surfactant (SDS) slightly increased the DIC removal rate in an acidic condition but significantly decreased the removal in neutral and alkaline conditions. Coexisting cationic surfactants not only influenced the kinetics but also altered the transformation mechanism of DIC by MnO. Decarboxylation is the main transformation mechanism of DIC in the presence of CTAB, while both decarboxylation and hydroxylation are the main transformation mechanisms in the absence of CTAB.
含胺药物是废水中和环境水中最常检测到的药物。它们通常可以被氧化锰（MnO）降解，氧化锰是土壤中常见的天然氧化剂。表面活性剂通常与废水中的药物共存。一些含胺药物，如双氯芬酸（DIC），是酸性的，因此在中性条件下是离子化合物。这些化合物因此具有与表面活性剂相似的性质。因此，表面活性剂可能会影响 MnO 对 DIC 的吸附和降解过程。本研究考察了不同类型表面活性剂对 MnO 降解 DIC 的影响，添加了两种常见的可生物降解表面活性剂（十六烷基三甲基溴化铵（CTAB）和十二烷基硫酸钠（SDS））。结果表明，在中性和碱性条件下，阳离子表面活性剂（CTAB）显著提高了降解速率。另一方面，阴离子表面活性剂（SDS）在酸性条件下略微提高了 DIC 的去除率，但在中性和碱性条件下显著降低了去除率。共存的阳离子表面活性剂不仅影响动力学，还改变了 MnO 对 DIC 的转化机制。在 CTAB 的存在下，脱羧是 DIC 的主要转化机制，而在没有 CTAB 的情况下，脱羧和羟化都是主要的转化机制。
