State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu, PR China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu, PR China.
Sci Total Environ. 2021 Jul 15;778:146278. doi: 10.1016/j.scitotenv.2021.146278. Epub 2021 Mar 8.
The compositional characteristics of dissolved organic matter (DOM) in pharmaceutical wastewater effluent can affect the further improvement and application of the ozone treatment process. The present study investigated the changes of chemical structures, molecular weight (MW) distribution, hydrophobicity/hydrophilicity distribution, fluorescence properties and the molecular composition of DOM in pharmaceutical wastewater effluent during ozonation. Besides, the toxicity change of pharmaceutical wastewater effluent during ozonation was estimated. The results show that ozone is prone to attack high MW fractions, which contributes the most to the UV value and could improve the biodegradability of refractory DOM in pharmaceutical wastewater effluent. Hydrophobic acid contained the most aromatic and unsaturated bonded organic matter, and was more readily oxidized under ozonation. In fluorescent components, ozonation significantly decreased humic-like acid compounds, and hydrophobic humic-like compounds exhibited the highest removal through parallel factor analysis. At the molecular level, the main organics removed by ozone were compounds with high H/C and low O/C, especially compounds where H/C >1.5. The CHO, CHON and CHOS compounds exhibited high removal under ozonation in formula classes. Lignin compounds, condensed aromatics compounds, and unsaturated hydrocarbons were effectively removed by ozone in compound classes. After ozonation, the number of lipid and sugar compounds increased. In addition, O/Cwa (the intensity-weighted average parameters of O/C) and NOSCwa (nominal oxidation state of carbon) were significantly positively correlated with acute toxicity on the luminescence. With the increase of ozone dose, the acute toxicity of pharmaceutical wastewater effluent after ozonation first decreased and then increased.
制药废水中溶解性有机物（DOM）的组成特征会影响臭氧处理工艺的进一步改进和应用。本研究考察了臭氧氧化过程中制药废水中 DOM 的化学结构、分子量（MW）分布、疏水性/亲水性分布、荧光特性和分子组成的变化。此外，还评估了制药废水中 DOM 在臭氧氧化过程中的毒性变化。结果表明，臭氧易攻击高分子量分数，这对 UV 值的贡献最大，并能提高制药废水中难生物降解的 DOM 的可生化性。疏水性酸含有最多的芳香和不饱和键有机物质，在臭氧氧化下更容易被氧化。在荧光成分中，臭氧氧化显著降低了类腐殖质酸化合物，而疏水性类腐殖质化合物通过平行因子分析显示出最高的去除率。在分子水平上，臭氧去除的主要有机物是 H/C 高且 O/C 低的化合物，特别是 H/C >1.5 的化合物。在分子式类别中，CHO、CHON 和 CHOS 化合物在臭氧氧化下的去除率较高。在化合物类别中，臭氧有效地去除木质素化合物、缩合芳烃化合物和不饱和烃。臭氧氧化后，脂质和糖化合物的数量增加。此外，O/Cwa（O/C 的强度加权平均值参数）和 NOSCwa（碳的名义氧化态）与发光的急性毒性呈显著正相关。随着臭氧剂量的增加，臭氧氧化后制药废水的急性毒性先降低后升高。
