School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi Province, 710055, China.
School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi Province, 710055, China; School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710049, China.
Chemosphere. 2021 Oct;280:130647. doi: 10.1016/j.chemosphere.2021.130647. Epub 2021 Apr 25.
In this study, we compared dissolved organic carbon (DOC) and UV removal efficiencies of the hybrid ozonation-coagulation (HOC) and pre-ozonation-coagulation (POC) processes for humic acid (HA) at pH 5 with AlCl•6HO as the coagulant. The DOC and UV removal efficiencies of the HOC process were higher than those of the POC process at ozone dosages less than 2.0 mg O (mg DOC). The ozone dosage was optimized at 0.3 and 0.1 mg O (mg DOC) for the HOC and POC processes, respectively, implying a more rigorous ozone dosage for the POC process. During the POC process, pre-ozonation was observed to increase the binding sites of HA (e.g., hydroxyl and carboxyl groups), improving the complexation of dissolved organic matter. For the HOC process, in addition to its role in the oxidation of organic matter, ozone also reacted with coagulants. The reaction between ozone and coagulants can facilitate the formation of Al. Moreover, the oxidation of •OH and ozone can increase the charge density of the HA binding sites, homogenizing the binding sites of HA and enhancing the complexation with Al.
在这项研究中，我们比较了混合臭氧氧化-混凝（HOC）和预臭氧化-混凝（POC）工艺在 pH5 下用 AlCl·6HO 作为混凝剂处理腐殖酸（HA）时的溶解有机碳（DOC）和 UV 去除效率。在臭氧剂量小于 2.0mgO(mgDOC)时，HOC 工艺的 DOC 和 UV 去除效率高于 POC 工艺。对于 HOC 和 POC 工艺，分别将臭氧剂量优化至 0.3 和 0.1mgO(mgDOC)，这意味着 POC 工艺需要更严格的臭氧剂量。在 POC 工艺中，预臭氧化被观察到增加了 HA 的结合位点（例如，羟基和羧基），从而改善了溶解有机物的络合作用。对于 HOC 工艺，除了在氧化有机物方面的作用外，臭氧还与混凝剂发生反应。臭氧与混凝剂之间的反应可以促进 Al 的形成。此外，•OH 和臭氧的氧化可以增加 HA 结合位点的电荷密度，使 HA 的结合位点均匀化，并增强与 Al 的络合作用。
