Membranes with Nanochannels Based on Pillar[6]arenes to Separate Xylenes

Abstract

Membrane separation technology has been widely applied in material separation fields. However, it still has the disadvantage of poor selectivity at nanometer and sub-nanometer scales. Here, two kinds of pillar[6]arene with opposite charges were prepared by modification, and the aligned nanochannel composite membrane was successfully constructed by directional assembly on a negatively charged silicon interface. The precise sieving properties of aligned channels were studied using the xylene isomer as a model molecule. It has been proved that the aligned channel can better maintain the pore size close to the macrocyclic molecules, which is beneficial to realize the customized construction of the through-ordered nanochannel. The experimental results show that the aligned nanochannel can selectively transport xylene isomers, and the flux (J) values of o, m, and p-xylene were 9.2, 11.6, and 171.3 nM m–2 h–1, respectively. Finally, the separation and purification of mixed samples have been achieved. This method provides a strategy for constructing ordered nanochannels.