State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology , Harbin 150090, People's Republic of China.
Water Desalination and Reuse Center, King Abdullah University of Science and Technology , Thuwal 4700, Kingdom of Saudi Arabia.
Environ Sci Technol. 2016 May 3;50(9):4668-74. doi: 10.1021/acs.est.5b04151. Epub 2016 Apr 13.
In this work, ceramic ultrafiltration membranes deposited with different metal oxides (i.e., TiO2, Fe2O3, MnO2, CuO, and CeO2) of around 10 nm in thickness and similar roughness were tested for O/W emulsion treatment. A distinct membrane fouling tendency was observed, which closely correlated to the properties of the filtration-layer metal oxides (i.e., surface hydroxyl groups, hydrophilicity, surface charge, and adhesion energy for oil droplets). Consistent with the distinct bond strength of the surface hydroxyl groups, hydrophilicity of these common metal oxides is quite different. The differences in hydrophilicity consequently lead to different adhesion of these metal oxides toward oil droplets, consistent with the irreversible membrane fouling tendency. In addition, the surface charge of the metal oxide opposite to that of emulsion can help to alleviate irreversible membrane fouling in ultrafiltration. Highly hydrophilic Fe2O3 with the lowest fouling tendency could be a potential filtration-layer material for the fabrication/modification of ceramic membranes for O/W emulsion treatment. To the best of our knowledge, this is the first study clearly showing the correlations between surface properties of filtration-layer metal oxides and ceramic membrane fouling tendency by O/W emulsion.
在这项工作中，测试了沉积有不同金属氧化物（即 TiO2、Fe2O3、MnO2、CuO 和 CeO2）的陶瓷超滤膜，这些金属氧化物的厚度约为 10nm，且具有相似的粗糙度，用于处理 O/W 乳液。观察到明显的膜污染趋势，这与过滤层金属氧化物的性质密切相关（即表面羟基、亲水性、表面电荷和油滴附着能）。与表面羟基的明显键强度一致，这些常见金属氧化物的亲水性有很大的不同。亲水性的差异导致这些金属氧化物对油滴的附着能力不同，这与不可逆的膜污染趋势一致。此外，与乳液相反的金属氧化物的表面电荷有助于减轻超滤过程中的不可逆膜污染。具有最低污染趋势的高亲水性 Fe2O3 可能是用于制备/修饰用于 O/W 乳液处理的陶瓷膜的潜在过滤层材料。据我们所知，这是首次清楚地表明过滤层金属氧化物的表面性质与 O/W 乳液陶瓷膜污染趋势之间的相关性的研究。
