Breite Daniel, Went Marco, Prager Andrea, Kuehnert Mathias, Schulze Agnes
Leibniz Institute of Surface Engineering (IOM), Permoserstr. 15, 04318 Leipzig, Germany.
Polymers (Basel). 2018 Dec 20;11(1):3. doi: 10.3390/polym11010003.
Membrane filters are designed for selective separation of components from a mixture. While separation by size might be the most common approach, other characteristics like charge can also be used for separation as presented in this study. Here, a polyether sulfone membrane was modified to create a zwitterionic surface. Depending on the pH value of the surrounding solution the membrane surface will be either negatively or positively charged. Thus, the charged state can be easily adjusted even by small changes of the pH value of the solution. Charged polystyrene beads were used as model reagent to investigate the pH dependent selectivity of the membrane. It was found that electrostatic forces are dominating the interactions between polystyrene beads and membrane surface during the filtration. This enables a complete control of the membrane's selectivity according to the electrostatic interactions. Furthermore, differently charged beads marked with fluorescent dyes were used to investigate the selectivity of mixtures of charged components. These different components were successfully separated according to their charged state proving the selectivity of the invented membrane.
膜过滤器旨在从混合物中选择性分离成分。虽然按尺寸分离可能是最常见的方法，但本研究表明，电荷等其他特性也可用于分离。在此，对聚醚砜膜进行了改性，以形成两性离子表面。根据周围溶液的pH值，膜表面将带负电或正电。因此，即使溶液的pH值有微小变化，电荷状态也能轻松调节。使用带电聚苯乙烯珠作为模型试剂，研究膜的pH依赖性选择性。结果发现，在过滤过程中，静电力主导着聚苯乙烯珠与膜表面之间的相互作用。这使得能够根据静电相互作用完全控制膜的选择性。此外，使用标记有荧光染料的不同电荷的珠子来研究带电成分混合物的选择性。这些不同的成分根据其电荷状态成功分离，证明了所发明膜的选择性。
