State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, P. R. China.
Environ Sci Technol. 2021 Jan 19;55(2):1270-1278. doi: 10.1021/acs.est.0c06835. Epub 2020 Dec 29.
The demand for thin-film composite (TFC) nanofiltration membranes with superior permeance and high rejection is gradually increasing for seawater desalination and brackish water softening. However, improving the membrane permeance remains a great challenge due to the formation of excrescent polyamide in the substrate pores and thick polyamide film. Herein, we fabricated a high-performance TFC nanofiltration membrane via a classical interfacial polymerization reaction on a two-dimensional lamellar layer of transition-metal carbides (MXene). The MXene layer promoted the absorption of the reactive monomer, and higher amine monomer concentration facilitated the self-sealing and self-termination of interfacial polymerization to generate a thinner outer polyamide film from 68 to 20 nm. The almost nonporous lamellar interface inhibited the formation of inner polyamide in the substrate pores. In addition, the MXene lamellar layer could be eliminated by mild oxidation after interfacial polymerization to avoid imparted additional hydraulic resistance. The resulting TFC membrane conferred a high rejection above 96% for NaSO and excellent permeance of 45.7 L·m·h·bar, which was almost 4.5 times higher than that of the control membrane (10.2 L·m·h·bar). This research provides a feasible strategy for fabricating a high-performance nanofiltration membrane using two-dimensional nanosheets as a templated interface.
对具有优异渗透性和高截留率的薄膜复合(TFC)纳滤膜的需求逐渐增加,以用于海水淡化和苦咸水软化。然而,由于基质孔中异常聚酰胺的形成和厚的聚酰胺膜,提高膜渗透性仍然是一个巨大的挑战。在此,我们通过在二维过渡金属碳化物(MXene)层上的经典界面聚合反应制造了一种高性能 TFC 纳滤膜。MXene 层促进了反应性单体的吸收,较高的胺单体浓度促进了界面聚合的自封闭和自终止,从而生成了更薄的外层聚酰胺膜(从 68nm 减至 20nm)。几乎无孔的层状界面抑制了基质孔内聚酰胺的形成。此外,在界面聚合后,通过温和氧化可以去除 MXene 层状层,以避免赋予额外的水力阻力。所得的 TFC 膜对 NaSO 的截留率超过 96%,渗透通量为 45.7 L·m·h·bar,几乎是对照膜(10.2 L·m·h·bar)的 4.5 倍。这项研究为使用二维纳米片作为模板界面制造高性能纳滤膜提供了一种可行的策略。