Advanced oxidation processes (AOPs) for wastewater treatment have attracted much attention for their efficient capability in destroying persistent and toxic organic compounds. In this study, we reported a simple impregnation-calcination method to fabricate ZnO modified TiO₂ (Zn-TiO₂) nanocomposites and employed them as catalysts for degradation of organic pollutants in water. The results show that 7at%Zn-TiO₂ exhibits much better performances of photocatalysis, catalytic ozonation, and photocatalytic ozonation than pure TiO₂, which could be due to its richer surface hydroxyl groups and higher separation efficiency of photogenerated electron-hole pairs. The total organic carbon (TOC) removal efficiency of salicylic acid (SA) in UV/O₃/7at%Zn-TiO₂ is higher than the sum of those in UV/7at%Zn-TiO₂ and O₃ processes, indicative of a synergistic effect between photocatalysis and ozonation. Mechanism studies demonstrated that the active species such as H₂O₂, h⁺, OH, O₂⁻ and ¹O₂ are responsible for SA degradation. Meanwhile, the intermediates of SA mineralization were identified by HPLC–MS and its mineralization pathway was proposed. Reusability test verifies a high stability of 7at%Zn-TiO₂ in the photocatalytic ozonation process, and the catalyst can be applied in a wide pH range of aqueous solution from 3.5 to 10.0. This work puts forward a new application of the easily available Zn-TiO₂ nanocomposites and might drive the advance of photocatalytic ozonation approach for water purification.

中文翻译：

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ZnO修饰的TiO ₂纳米复合材料促进光催化臭氧氧化降解有机污染物

用于废水处理的高级氧化工艺（AOP）能够有效清除持久性和有毒有机化合物，因此备受关注。在这项研究中，我们报道了一种简单的浸渍-煅烧方法来制备ZnO改性的TiO ₂（Zn-TiO ₂）纳米复合材料，并将其用作降解水中有机污染物的催化剂。结果表明，7at％Zn-TiO ₂具有比纯TiO ₂更好的光催化，催化臭氧化和光催化臭氧性能，这可能是由于其表面羟基更丰富，光生电子-空穴对的分离效率更高。水杨酸（SA）在UV / O中的总有机碳（TOC）去除效率₃ / 7at％Zn-TiO ₂高于UV / 7at％Zn-TiO ₂和O ₃工艺中的总和，表明光催化和臭氧化之间具有协同作用。机理研究表明，活性物质如H ₂ O ₂，h ⁺，哦， Ø ₂ ^-和¹ Ø ₂负责SA降解。同时，通过HPLC-MS鉴定了SA成矿的中间体，并提出了其成矿途径。可重复使用性测试验证了7at％Zn-TiO ₂在光催化臭氧化过程中的高稳定性，并且该催化剂可在3.5至10.0的宽pH范围内使用。这项工作提出了易于获得的Zn-TiO ₂纳米复合材料的新应用，并可能推动光催化臭氧化水净化方法的发展。