Performance studies of mixed matrix membranes for gas separation: A review

Utilizing low ZIF-8 loading for an asymmetric PSf/ZIF-8 mixed matrix membrane for CO2/CH4 separation

Illustration of gas permeation across different zif-8 loading in asymmetric membrane.

A high performance O2selective membrane based on CAU-1-NH2@polydopamine and the PMMA polymer for Li–air batteries

A novel oxygen selective membrane was prepared and assembled in Li-air batteries operating under real air conditions with 30% RH. Due to its high O₂permeability, remarkable CO₂capture ability and excellent hydrophobic behavior, extremely stable cycling performance was achieved.

Thin film nanocomposite embedded with polymethyl methacrylate modified multi-walled carbon nanotubes for CO2 removal

Thin film nanocomposite loaded with milled polymethyl methacrylate grafted multi-walled carbon nanotubes achieved 29%, 47% and 9% increment in CO₂ permeance, CO₂/N₂ and CO₂/CH₄ selectivity respectively compared to its thin film composite counterpart.

Facile modification of ZIF-8 mixed matrix membrane for CO2/CH4 separation: synthesis and preparation

The MMM consisting of ZIF-8 after facile ammonia modification provides excellent separation properties with increases CO₂ permeability up to 43% and ideal CO₂/CH₄ selectivity up to 72% even only 0.5 wt% fillers were embodied.

Preparation and Characterization of Newly Developed Polysulfone/Polyethersulfone Blend Membrane for CO2 Separation

Polymeric membranes suffer from so called upper bound tradeoff between permeability and selectivity as described by Robeson. Polymer blending is a valuable technique to tune the properties of polymeric membranes by physical mixing of different polymers in a single mixture. In this study, preparation and characterization of newly developed polysulfone/polyethersulfone (PSF/PES) blend flat sheet dense membranes is described for CO2/CH4 separation. Blend membranes with different blending ratios were prepared and the developed membranes were characterized by FESEM, FTIR and TGA to see the effect of blend ratio on morphology, bonding and thermal stability respectively. Permeability of CO2 and CH4 gases in pressure range of 2-10 bar is recorded to find out the ideal selectivity of prepared membranes. The results are discussed and compared with individual polymer membranes.

Effects of Montmorillonite (MMT) Inorganic Fillers on Polyvinylidene (PVDF) Mixed Matrix Membrane

Asymmetric nanoclay-polyvinylidene (PVDF) mixed matrix membranes (MMMs) were prepared by the reaction of various amount of montmorillonite (MMT) nanoclay mineral with PVDF. The MMMs were fabricated via dry-wet phase inversion method withN,N-dimethyl-acetamide (DMAc) as the solvent and ethanol as the coagulant. The fabricated MMMs were characterized by means of fourier-transform infrared (FTIR) and scanning electron microscopy (SEM). The separation performances of the prepared membranes were evaluated by pure gases (CO2and CH4). From the FTIR spectrum, MMMs exhibited new peaks compared to pristine PVDF membrane, indicating assimilation of MMT into the PVDF membrane. The morphology of the membranes depends on the clay mineral loading as confirmed by SEM. PVDF/3wt% MMT MMM showed the highest CO2permeance and CO2/CH4selectivity relative to neat PVDF membrane.

Mixed matrix membranes with strengthened MOFs/polymer interfacial interaction and improved membrane performance

MOFs-based mixed matrix membranes (MMMs) have attracted extensive attention in recent years due to their potential high separation performance, the low cost, and good mechanical properties. However, it is still very challenging to achieve defect-free interface between micrometer-sized MOFs and a polymer matrix. In this study, [Cd2L(H2O)]2·5H2O (Cd-6F) synthesized using 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) as an organic ligand was introduced into the 6FDA-ODA polyimide matrix to achieve novel MOF MMMs. A specific interfacial interaction between MOF crystals and polymer chains was innovatively targeted and achieved through in situ polymerization procedure. The enhanced adhesion between MOF particles and polymer phase was observed, and the improved interfacial interaction between Cd-6F and the 6FDA-ODA polyimide matrix was confirmed by detailed characterizations including FTIR and NMR. In the meantime, the gas permeance and selectivity of the MMMs are strongly dependent on their morphology. The MMM derived from in situ polymerization presents excellent interfaces between micrometer-sized MOF crystals and the polymer matrix, resulting in increased permeability and selectivity. The strategy shown here can be further utilized to select the MOF/polymer pair, eliminate interfacial voids, and improve membrane separation performance of MOFs-based MMMs.

Rapid room temperature syntheses of zeolitic-imidazolate framework (ZIF) nanocrystals

Here we report a simple solvent mixture controlled rapid room temperature syntheses for facile access to uniform zeolitic-imidazolate framework (ZIF) nanocrystals.

Zeolitic imidazolate framework composite membranes and thin films: synthesis and applications

The recent developments of zeolitic imidazolate framework (ZIF) membranes/films, ZIF–polymer mixed matrix membranes and their applications are reviewed in this article.

Dual-functionalized mesoporous TiO2 hollow nanospheres for improved CO2 separation membranes

Simultaneous improvement in CO₂ permeability and CO₂/N₂ selectivity was obtained from mixed matrix membranes consisting of graft copolymer and dual-functionalized mesoporous TiO₂ hollow nanospheres (f-MTHSs).