Morphologically Tunable MOF Nanosheets in Mixed Matrix Membranes for CO₂ Separation

Abstract

This study first develops a facile method to synthesize zeolitic imidazolate framework cuboid (ZIF-C) nanosheets with tunable thickness from 70 to 170 nm from aqueous polymer solutions. The obtained ZIF-C nanosheets were characterized by various techniques, including X-ray diffractometry (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), N2 adsorption and thermogravimetric analysis (TGA), to understand their compositional and structural properties. The synthesized ZIF-Cs nanosheets with different thicknesses were further applied as nanofillers to prepare Pebax-based mixed matrix membranes (MMMs) to study the effect of the morphology on membrane properties and CO2/N2 separation performances under different relative humidity (RH) conditions. Results reveal that the incorporation of these ZIF-Cs simultaneously enhances CO2 permeability and CO2/N2 selectivity in the mixed matrix membranes. In addition, MMMs with the thickest ZIF-C nanosheet present better performance. A CO2 permeability of 387.2 Barrer accompanied with a CO2/N2 selectivity of 47.1 has been documented, nearly doubled in CO2 permeability with slightly increased selectivity compared with membranes containing thinner nanosheets.

Highly efficient fluorescent chemosensor for nitro antibiotic detection based on luminescent coordination polymers with 2,6-di(4-carboxyphenyl)pyrazine

“…The emergence of porous coordination polymers (PCPs) with unprecedented diversity in structures and functions has become a significant materials chemistry achievement over the past two decades. Crystalline materials' porosity and tailored functionality have attracted extensive attention in application areas of gas storage, [1][2][3] separation, [4][5][6] luminescence, [7][8][9] piezoelectricity, [10][11][12] catalysis, [13][14][15] magnetism, [16][17][18] biomedicine, [19][20][21] sensors, [22][23][24] and so on. Considering their large specific surface area, adjustable pore size, and surface chemical sites, compared to all the applications, exploring the potential use of PCPs as chemical sensors has broad application prospects and extraordinary significance.…”

A Review of the Recent Progress in the Development of Nanocomposites Based on Poly(ether-block-amide) Copolymers as Membranes for CO2 Separation

“…Other MMMs were prepared by dispersing ZIF-8 in Pebax 2533 with the addition of Pluronic P123 surfactant [ 67 ]. A research study focused on Zeolitic Imidazolate Framework cuboid (ZIF-C) nanosheets with tunable thickness from 70 to 170 nm, obtained via a facile method from aqueous polymer solutions, reported better CO 2 separation performance for the MMMs containing the thickest ZIF-C nanosheets [ 68 ].…”

“…Zeolitic Imidazolate Framework cuboid (ZIF-C) nanosheets with tunable thickness (from 70 to 170 nm) showed the highest CO 2 permeability in the case of large thickness, while the selectivity was enhanced using the fillers with medium size [ 68 ]. The reason for this behavior is ascribed to greater effects of the selective CO 2 adsorption of thicker ZIF-C nanosheets due to the increased available pathway for gases between layers.…”

Integration of Stable Ionic Liquid-Based Nanofluids into Polymer Membranes. Part II: Gas Separation Properties toward Fluorinated Greenhouse Gases

“…Given the promising results obtained with MMMs, mainly focused on CO 2 selective separation [42][43][44][45][46], in this work we explore for the first time the use of MMMs functionalized with exfoliated graphene nanoplatelets (xGnP) for the separation of HFCs. In this sense, the role of pristine graphene in this type of applications, given its bidimensional structure and the fact that it is impermeable to gases, is to generate some degree of tortuosity within the polymer matrix and thus, modify the path of the gas molecules during permeation [47,48].…”