An Organoselective Zirconium‐Based Metal–Organic‐Framework UiO‐66 Membrane for Pervaporation

Abstract

A UiO‐66 membrane was synthesized on an Al2O3 support by an in situ solvothermal method with a coordination modulation technique. We first confirmed the organic selectivity of the UiO‐66 membrane for methanol, ethanol, and acetone in mixtures with water. The membrane displayed highly stable pervaporation performance during the test and exhibited a separation factor of approximately 4.3 and a flux of 1.28 kg m–2 h–1 in ethanol/water. From the water and ethanol vapor adsorption measurement, the water uptake was lower in a binary system than that in a single system, although the ethanol uptake was similar for the binary and single systems. Therefore, the ethanol selectivity of the UiO‐66 membrane can be attributed to the preferential adsorption of the organic compound rather than water, as confirmed by a binary‐vapor adsorption measurement.

Metal-organic framework UiO-66 membranes

“…UiO-66 membranes were further developed by using modulated synthesis [59,[90][91][92][93][94][95][96]. The so-called coordination modulation method was initially proposed by Tsuruoka et al [97] and employed in UiO-66 crystal preparation by Schaate et al [98].…”

Mass transport through metal organic framework membranes

“…1 and diffuse through the channels of MOF membranes, hence the ethanol-selective permeation was demonstrated. In the meantime, smaller molecules, like methanol, obtained higher flux; and larger ones, like p-/mxylene (0.67/0.71 nm) [143] obtained lower flux. This can be explained by the molecular sieving effect of UiO-66 membranes.…”

“…While, more difficulties lie in the fabrication of MOF membranes than powders, and they still need to be synthesized on the porous substrates. Generally, the synthesis methods include the direct growth and secondary growth [91,100,143]. In order to obtain well-intergrown continuous MOF membranes, the modification of substrates is necessary as well as some novel method like microfluidic process.…”

Membranes for bioethanol production by pervaporation

“…The effective membrane thickness was merely 0.5–1 μm. The thinner membranes displayed highly stable PV performance and had elevated permeation fluxes of 1490 g·m −2 ·h −1 at 50 °C and 3150 g·m −2 ·h −1 at 60 °C, respectively, with separation factors slightly less than 5 in a 10/90 ethanol/water mixture [ 227 ]. Despite unique advantages of MOFs, such as high porosity, ordered structures, and tunable chemical functionality, a few MOFs membranes have been investigated into PV to date as a result of their poor chemical stability.…”