Mixed matrix membranes consisting of PDMS and IL@MoS2 for enhancing 2-phenylethanol pervaporation separation

Abstract

The MoS2-based mixed matrix membranes (MMMs) exhibited excellent pervaporation separation for aromatic compounds, but the narrow interlayer spacing and few affinity sites in MoS2 limited the simultaneous improvement in the total flux and separation factor. Therefore, constructing 2-PE transport channels and affinity sites in MMMs is of significant importance to improve the pervaporation separation performance. Herein, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (IL) was intercalated into the interlayer of the molybdenum disulfide (MoS2) under electrostatic and concentration diffusion interactions to obtain IL@MoS2. Then, IL@MoS2 was incorporated into polydimethylsiloxane (PDMS) to prepare MMMs for efficient 2-PE separation, which had good miscibility with polymer matrix. The total flux, separation factor and pervaporation separation index of as-prepared MMMs reached 1466 g m−2 h−1, 33 and 47,571 g m−2 h−1, separately, which increased by 26 %, 31 % and 44 % compared with that of PDMS embedding with MoS2. This is because IL@MoS2 in MMMs not only can afford 2-PE transport channels, but also provide 2-PE affinity sites due to the hydrogen bonds and π-π interactions, which promotes the solubility of 2-PE in MMMs. When the concentration of maltol increased to 1500 ppm in 2-PE aqueous solution, the 2-PE flux and separation factor of 2-PE/water only decreased by 23 % and 26 %, revealing that MMMs had good 2-PE selectivity in 2-PE/maltol/water mixture. In addition, it displayed exceptional durability during 168 h testing, demonstrating that this membrane had a good application prospect for 2-PE separation.