Pre-ozonation is often used before ultrafiltration (UF) to control membrane fouling, usually by supplying ozone into water or wastewater via aeration. However, the role of aeration in pre-ozonation for mitigation of membrane fouling has not been well elucidated. Hence, in this study, bovine serum albumin (BSA) was used as a protein-type foulant in experiments on the outcomes and underlying mechanisms of pre-ozonation. The change in the membrane fouling behavior, the transformation of BSA, and the fouling-layer properties were investigated after pre-ozonation with and without aeration. The results showed that the membrane fouling notably declined after pre-ozonation, which mainly attributed to the synergistic effect between ozone oxidation and aeration. Ozone oxidation unfolded the BSA molecules and exposed their hydrophobic groups, and these unfolded BSA aggregated and adhered to the surface of the microbubbles produced by aeration. This induced BSA foaming and aggregation in the ozonated suspension. With pre-ozonation for a short contact time of 5 min, small BSA aggregates in water were retained on the UF membrane surface to form a highly porous deposition layer with a low filtration resistance. With pre-ozonation for a contact time of 10 min or longer, BSA foaming led to the formation of large aggregates that were efficiently removed from water in the ozone reactor, which greatly reduced the foulant loading of the water and its subsequent membrane fouling rate. In contrast, when quantitative and quiescent ozonation was performed without aeration, ozone oxidation alone worsened the membrane fouling propensity of the BSA solution.

预臭氧化通常在超滤（UF）之前用于控制膜的结垢，通常是通过曝气将臭氧供应到水或废水中来进行的。然而，尚未充分阐明通气在预臭氧化中用于减轻膜污染的作用。因此，在这项研究中，牛血清白蛋白（BSA）在预臭氧化的结果和潜在机理的实验中被用作蛋白质型污垢。在有和没有充气的情况下进行预臭氧化后，研究了膜结垢行为的变化，BSA的转化以及结垢层的性质。结果表明，预臭氧化处理后膜结垢明显减少，这主要归因于臭氧氧化与通气之间的协同作用。臭氧氧化使BSA分子展开并暴露其疏水基团，这些未折叠的BSA聚集并粘附在通气过程中产生的微气泡表面上。这在臭氧化的悬浮液中引起BSA发泡和聚集。通过预臭氧化5分钟的短接触时间，水中的少量BSA聚集体会保留在UF膜表面上，以形成具有低过滤阻力的高度多孔的沉积层。在预臭氧化过程中，接触时间为10分钟或更长时间，BSA发泡导致形成大的聚集体，这些聚集体可在臭氧反应器中从水中有效去除，这大大降低了水的结垢负荷及其随后的膜结垢率。相反，当在不充气的情况下进行定量和静态的臭氧化时，仅臭氧氧化会恶化BSA溶液的膜结垢倾向。