Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, PR China.
Department of Civil Engineering, The University of Hong Kong, Pokfulam HW619B, Hong Kong, PR China.
J Colloid Interface Sci. 2019 Mar 22;540:382-388. doi: 10.1016/j.jcis.2019.01.033. Epub 2019 Jan 11.
Thin film composite (TFC) polyamide membranes set the golden standard for reverse osmosis technology, but tuning their permeability and selectivity remains a major challenge because of the inherent permeability-selectivity trade-off. Creating nano-sized voids within the polyamide rejection layer can tune the membrane roughness and increase its effective filtration area to improve the water permeability. Here we prepare nano-foamed polyamide rejection layers by adding sodium bicarbonate into the aqueous solution of amine monomers. We show a systematic evolution of the roughness structure of polyamide membranes, with increasingly leaf-like and belt-like features appearing under enhanced nano-foaming conditions. These nano-foamed features can result in remarkable improvements in both water permeability and salt rejection and reduce membrane fouling propensity at the same time. Our study paves a new research direction for designing future generation of desalination membranes, which holds vast potential to reduce the cost and energy consumption of desalination while achieving improved product water quality.
薄膜复合（TFC）聚酰胺膜为反渗透技术设定了黄金标准，但由于固有的渗透性-选择性权衡，调整其渗透性和选择性仍然是一个主要挑战。在聚酰胺排斥层内创建纳米级空隙可以调整膜粗糙度并增加其有效过滤面积，从而提高水渗透性。在这里，我们通过将碳酸氢钠加入到胺单体的水溶液中来制备纳米发泡聚酰胺排斥层。我们展示了聚酰胺膜粗糙度结构的系统演化，在增强的纳米发泡条件下，越来越多的叶片状和带状特征出现。这些纳米发泡特征可以显著提高水渗透性和盐排斥率，同时降低膜污染倾向。我们的研究为设计新一代脱盐膜开辟了新的研究方向，这有望降低脱盐的成本和能源消耗，同时提高产品水的质量。
