Numerous studies report on the synergy between ozonation and photocatalytic oxidation (TiO₂/UVA), which could open the way to the application of photocatalytic ozonation (PCOz) in water treatment. With the aim of establishing the existence of this synergy and its origin, in this work, using TiO₂ P25, 365 nm UVA LEDs and ozone transferred doses up to 5 mg (mg DOC₀)⁻¹ (DOC₀ 7 – 10 mg L⁻¹), a systematic study has been carried out featuring the effect of pH, alkalinity and water matrix in each of the systems involved in PCOz, with special attention to the role of organics adsorption onto TiO₂. In ultrapure water, an increase in pH and carbonates content exerted a slight negative effect on the photocatalytic degradation of primidone (low adsorption onto TiO₂ and mainly abated by free HO^•), this effect being higher on its mineralization. The negative effect of pH and alkalinity was much stronger for oxalic acid (high tendency to adsorb and mainly oxidized by positive holes). Accordingly, the results obtained at pH < pH_pzc (point of zero charge of the catalyst) in ultrapure water cannot at all be extrapolated to secondary effluents, since their composition negatively affects the photocatalytic performance. At the experimental conditions applied, only for the secondary effluent a synergy between O₃/UVA and TiO₂/UVA systems was observed. This synergy would be related, on the one hand, to the generation, from the matrix itself, of reactive entities or intermediates that promote the decomposition of ozone into HO^•; and, on the other hand, to an increase in catalyst activity as the matrix UVA absorption decreases, rather than from direct interactions between both systems. Despite de above, ozone requirement to achieve a significant reduction of DOC is high and would only be an interesting strategy for the elimination of ozone-refractory micropollutants.

大量研究报告了臭氧化和光催化氧化（TiO ₂ /UVA）之间的协同作用，这为光催化臭氧化（PCOz）在水处理中的应用开辟了道路。为了确定这种协同作用的存在及其起源，在这项工作中，使用 TiO ₂ P25、365 nm UVA LED 和臭氧转移剂量高达 5 mg (mg DOC ₀ ) ^-1 (DOC ₀ 7 – 10 mg L ^-1 )，系统研究了 PCOz 涉及的每个系统中 pH、碱度和水基质的影响，特别关注有机物吸附到 TiO ₂上的作用. 在超纯水中，pH 值和碳酸盐含量的增加对扑米酮的光催化降解产生轻微的负面影响（对 TiO _{2 的}吸附低，主要通过游离 H2O ^•减弱），这种影响对其矿化作用更大。pH 值和碱度对草酸的负面影响要强得多（高吸附倾向，主要被正空穴氧化）。因此，在超纯水中在 pH < pH _pzc（催化剂的零电荷点）下获得的结果根本不能外推到二次流出物，因为它们的组成会对光催化性能产生负面影响。在所应用的实验条件下，仅对于二次出水，O ₃ /UVA 和 TiO ₂之间存在协同作用观察到 /UVA 系统。这种协同作用将是相关的，在一方面，要产生，从基质促进臭氧成HO的分解反应性实体或中间体的本身，^• ; 另一方面，随着基质 UVA 吸收的减少，而不是两个系统之间的直接相互作用，催化剂活性增加。尽管如此，实现 DOC 显着减少的臭氧需求很高，并且只是消除耐臭氧微污染物的有趣策略。