Anti-fouling membranes for organic solvent nanofiltration (OSN) and organic solvent ultrafiltration (OSU): Graft modified polybenzimidazole (PBI)
Anti-fouling membranes for organic solvent nanofiltration (OSN) and organic solvent ultrafiltration (OSU): Graft modified polybenzimidazole (PBI)
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DOI：
10.1016/j.memsci.2022.120977
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发表时间：
2022-09
影响因子：
9.5
通讯作者：
Adam Oxley;A. Livingston
中科院分区：
文献类型：
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作者：
Adam Oxley;A. Livingston
污垢是成功进行膜分离的主要障碍之一。在含水系统中，污垢被很好地表征，并且建立了污垢减少技术。然而，在有机溶剂中，膜污染还没有得到很好的理解。在这项工作中，我们制造防污有机溶剂稳定的聚苯并咪唑（PBI）膜的表面接枝改性与线性聚（乙二醇）（PEG）和聚（丙二醇）（PPG）。接枝改性是减少结垢的有效方法。然而，防污性能取决于改性聚合物和溶剂之间的相互作用。在水中，亲水性PEG接枝改性剂具有有利的改性剂-水相互作用，并在膜表面上提供抗污染的空间层。然而，疏水性PPG接枝改性剂具有不利的改性剂-水相互作用，并且不提供防污性能。相反地，在极性有机溶剂中，相对于用相同分子量的PEG进行的接枝改性，用PPG进行的接枝改性显示出上级改性剂-溶剂相互作用和上级防污性能。在非极性溶剂中，PEG和PPG改性剂都具有不利的改性剂-溶剂相互作用，并提供最小的防污性能。接枝改性后的防污性能与接枝聚合物在溶液中的流体动力学直径密切相关，并且用于制造防污OSN和OSU膜的最佳接枝聚合物的选择显著地依赖于溶剂。
Fouling is one of the major obstacles to successful membrane-based separations. In aqueous systems, fouling is well characterised and fouling reduction techniques are established. However, in organic solvents, membrane fouling is not well understood. In this work we manufactured anti-fouling organic solvent stable polybenzimidazole (PBI) membranes by graft modifying the surface with linear poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG). Graft modification provided an effective method of reducing fouling. However, the anti-fouling properties were dependent on the interactions between the modifying polymer and the solvent. In water, the hydrophilic PEG graft modifiers had favourable modifier-water interactions and provided an anti-fouling steric layer on the surface of the membrane. However, hydrophobic PPG graft modifiers had unfavourable modifier-water interactions and provided no anti-fouling properties. Conversely, in polar organic solvents, graft modification with PPG showed superior modifier-solvent interactions, and superior anti-fouling properties, relative to graft modification with the same molecular weight PEG. In non-polar solvents, both the PEG and PPG modifiers had unfavourable modifier-solvent interactions and provided minimal anti-fouling properties. The anti-fouling properties after graft modification were closely correlated to the hydrodynamic diameter of the grafting polymer in solution, and the selection of an optimal grafting polymer for manufacturing anti-fouling OSN and OSU membranes is significantly solvent dependant.