Synergistic enhancement of CO2/N2 separation performance via Ce-MOF-infused chitosan mixed matrix membrane.

Reticular chemistry, exemplified by metal-organic frameworks (MOFs), has proven invaluable in creating porous materials with finely tuned structures to address critical global energy and environmental challenges. In this context, the need for efficient carbon dioxide (CO2) capture and utilization has taken center stage. One promising approach involves the integration of MOFs into polymer matrix to develop mixed matrix membranes (MMMs). In this work, cerium-based MOFs (Ce-MOF) were selected due to their robust CO2 capture capabilities, while chitosan (CS) was chosen as the polymer matrix due to its reasonably good selectivity and balanced CO2 permeance for the development of MMMs for CO2/N2 (20/80 vol%) separation. A comprehensive suite of analytical techniques, including FTIR, XRD, FESEM, XPS, TGA, EDX, FETEM, and BET, was applied for precise characterization of both the MOF and MMMs. Various operational parameters, such as Ce-MOF content and temperature, were systematically explored to investigate the CO2 capture efficiency of the synthesized MMMs. The results revealed that the optimized Ce-MOF-embedded CS MMMs consistently outperformed the bare CS membranes.

New generation mixed matrix membrane for CO2 separation: Transition from binary to quaternary mixed matrix membrane.

Contemporary advances in material development associated with membrane gas separation refer to the cost-effective fabrication of high-performance, defect-free mixed matrix membranes (MMMs). For clean energy production, natural gas purification, and CO2 capture from flue gas systems, constituting a functional integration of polymer matrix and inorganic filler materials find huge applications. The broad domain of research and development of MMMs focused on the selection of appropriate materials, inexpensive membrane fabrication, and comparative study with other gas separation membranes for real-world applications. This study addressed a comprehensive review of the advanced MMMs wrapping various facets of membrane material selection; polymer and filler particle morphology and compatibility between the phases and the relevance of several fillers in the assembly of MMMs are analyzed. Further, the research on binary MMMs, their problems, and solutions to overcome these challenges have also been discussed. Finally, the future directions and scope of work on quaternary MMM are scrutinized in the article.

A Strategical Improvement in the Performance of CO2/N2 Gas Permeation via Conjugation of L-Tyrosine onto Chitosan Membrane.

Rubbery polymeric membranes, containing amine carriers, have received much attention in CO2 separation because of their easy fabrication, low cost, and excellent separation performance. The present study focuses on the versatile aspects of covalent conjugation of L-tyrosine (Tyr) onto the high molecular weight chitosan (CS) accomplished by using carbodiimide as a coupling agent for CO2/N2 separation. The fabricated membrane was subjected to FTIR, XRD, TGA, AFM, FESEM, and moisture retention tests to examine the thermal and physicochemical properties. The defect-free dense layer of tyrosine-conjugated-chitosan, with active layer thickness within the range of ~600 nm, was cast and employed for mixed gas (CO2/N2) separation study in the temperature range of 25-115 °C in both dry and swollen conditions and compared to that of a neat CS membrane. An enhancement in the thermal stability and amorphousness was displayed by TGA and XRD spectra, respectively, for the prepared membranes. The fabricated membrane showed reasonably good CO2 permeance of around 103 GPU and CO2/N2 selectivity of 32 by maintaining a sweep/feed moisture flow rate of 0.05/0.03 mL/min, respectively, an operating temperature of 85 °C, and a feed pressure of 32 psi. The composite membrane demonstrated high permeance because of the chemical grafting compared to the bare chitosan. Additionally, the excellent moisture retention capacity of the fabricated membrane accelerates high CO2 uptake by amine carriers, owing to the reversible zwitterion reaction. All the features make this membrane a potential membrane material for CO2 capture.

Mixed Matrix Membranes for Carbon Capture and Sequestration: Challenges and Scope.

Carbon dioxide (CO2) is a major greenhouse gas responsible for the increase in global temperature, making carbon capture and sequestration (CCS) crucial for controlling global warming. Traditional CCS methods such as absorption, adsorption, and cryogenic distillation are energy-intensive and expensive. In recent years, researchers have focused on CCS using membranes, specifically solution-diffusion, glassy, and polymeric membranes, due to their favorable properties for CCS applications. However, existing polymeric membranes have limitations in terms of permeability and selectivity trade-off, despite efforts to modify their structure. Mixed matrix membranes (MMMs) offer advantages in terms of energy usage, cost, and operation for CCS, as they can overcome the limitations of polymeric membranes by incorporating inorganic fillers, such as graphene oxide, zeolite, silica, carbon nanotubes, and metal-organic frameworks. MMMs have shown superior gas separation performance compared to polymeric membranes. However, challenges with MMMs include interfacial defects between the polymeric and inorganic phases, as well as agglomeration with increasing filler content, which can decrease selectivity. Additionally, there is a need for renewable and naturally occurring polymeric materials for the industrial-scale production of MMMs for CCS applications, which poses fabrication and reproducibility challenges. Therefore, this research focuses on different methodologies for carbon capture and sequestration techniques, discusses their merits and demerits, and elaborates on the most efficient method. Factors to consider in developing MMMs for gas separation, such as matrix and filler properties, and their synergistic effect are also explained in this Review.

Fabrication and Performance Evaluation of Industrial Alumina Based Graded Ceramic Substrate for CO2 Selective Amino Silicate Membrane.

The present study mainly focuses on the careful design of an amino-silicate membrane integrated on an asymmetric graded membrane substrate, comprised of a cost-effective macroporous industrial alumina based ceramic support with a systematic graded assemblage of sol-gel derived γ-alumina intermediate and silica-CTAB sublayer-based multilayered interface, specifically dedicated for the separation of CO2 gas from the binary gas mixture (CO2/N2) under nearly identical flue gas atmospheric conditions. The tailor-made industrial α-alumina-based porous ceramic support has been characterized in terms of apparent porosity, bulk density, flexural strength, microstructural feature, pore size, and its distribution to demonstrate its application feasibility toward the evolution of the subsequent membrane structure. The near surface morphology of the subsequent intermediate and submembrane layer has been carefully controlled via precisely scheming the colloidal chemistry and consequently implementing it during the deposition process of the respective γ-alumina and silica-CTAB precursor sols, whereas the potentiality of the quarantined amine groups in the final amino-silicate membrane has been methodically optimized by the appropriate heat treatment process. Finally, the real-time applicability of the hybrid amino-silicate membrane has been evaluated in terms of systematic analysis of the binary gas (CO2/N2) separation performance under variable operating conditions. The investigated ceramic membrane exhibited optimum CO2 permeance of 46.44 GPU with a CO2/N2 selectivity of 12.5 at 80 °C under a trans-membrane pressure drop of 0.8 bar having a feed and sweep side water flow rate of 0.03 mL/min, which shows its performance reliability at nearly identical flue gas operating conditions.