Pure‐silica <scp>MFI zeolite</scp> membrane by cooperative templating approach for ethanol‐water separation
Jiancheng Lan, Linzhe Li, Wensen Song, Hammad Saulat, Haowen Wu, Jianhua Yang, Chengmin Yang, Yang Li, Jinming Lu, Yan Zhang
Abstract
Abstract Pure‐silica MFI zeolite membrane composed of intergrown four prism crystals was fabricated by using tetrabutylammonium (TBA + ) and tetraethylammonium (TEA + ) as cooperating templates and the induced function of MFI seeds under synthesis solution with molar composition of 1TEOS:0.2TBAOH:0.2TEABr:180H 2 O. The ethanol/water separation factor was 64 with a flux of 1.40 kg m −2 hr −1 for 5 wt% ethanol/water mixture at 60°C. In contrast, single TBAOH and TEAOH template led to formation of uncontinuous MEL and MFI membrane respectively, without ethanol‐selectivity. The behavior of quaternary ammonium (TBA + and TEA + ) varied in different system: (a) In “TBA + + TEA + ” system, TBA + and TEA + were incorporated into MFI zeolite channel simultaneously; (b) In “TPA + + M + ” system (M = TEA or TBA), either TEA + or TBA + could not be occluded into channel, however, appropriate amount of TBA + could accelerate membrane crystallization, meanwhile increase in TEA + slowed down crystallization rate of MFI membrane. This work extends the alternative preparation approaches of ethanol perm‐selective MFI membrane.