Browsing by Author "Kuncharam, Bhanu Vardhan Reddy"

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3D self assembled graphene based cellulose acetate mixed matrix membranes for CO2/CH4 separation: An investigation
(Elsevier, 2025-03) Kuncharam, Bhanu Vardhan Reddy
This study investigates the development of three-dimensional (3D) Self-Assembled Graphene (SAG) and its potential as a filler material in mixed matrix membranes (MMMs) for efficient CO₂ separation. SAG was synthesized via a one-step hydrothermal treatment of graphene oxide (GO). Additionally, reduced graphene oxide (rGO) was synthesized via chemical reduction of GO and tested alongside SAG and GO as filler materials in cellulose acetate (CA) based MMMs. Structural and gas separation properties of SAG, rGO, and GO-based MMMs were compared to identify the superior material for CO₂ separation applications. Model biogas 40 % CO2 and 60 % CH4 is used for gas permeation testing. Characterization techniques such as X-ray Photoelectron Spectroscopy (XPS), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, and X-ray Diffraction (XRD) were employed to evaluate the structural and thermal properties of the fillers and membranes. Gas permeation studies revealed that MMMs containing SAG exhibited superior CO₂ separation performance compared to rGO and GO-based membranes. The 1 % SAG/CA MMMs showed highest CO2 permeability of 50.96 Barrers which is approximately 364 % higher than pure CA membrane, 178 % higher than GO based MMMs, and 133 % higher than rGO based MMMs.
Angular difference in human coronary artery governs endothelial cell structure and function
(Springer, 2022-10) Majumder, Syamantak; Kuncharam, Bhanu Vardhan Reddy
Blood vessel branch points exhibiting oscillatory/turbulent flow and lower wall shear stress (WSS) are the primary sites of atherosclerosis development. Vascular endothelial functions are essentially dependent on these tangible biomechanical forces including WSS. Herein, we explored the influence of blood vessel bifurcation angles on hemodynamic alterations and associated changes in endothelial function. We generated computer-aided design of a branched human coronary artery followed by 3D printing such designs with different bifurcation angles. Through computational fluid dynamics analysis, we observed that a larger branching angle generated more complex turbulent/oscillatory hemodynamics to impart minimum WSS at branching points. Through the detection of biochemical markers, we recorded significant alteration in eNOS, ICAM1, and monocyte attachment in EC grown in microchannel having 60o vessel branching angle which correlated with the lower WSS. The present study highlights the importance of blood vessel branching angle as one of the crucial determining factors in governing atherogenic-endothelial dysfunction.
Asymmetric mixed matrix membranes with zeolite imidazolate frameworks (ZIF-8, ZIF-67, bimetallic ZIF-8/67) and polyethersulfone for high flux and high selective hydrogen separation
(Wiley, 2025-03) Pani, Ajaya Kumar; Kuncharam, Bhanu Vardhan Reddy
For producing high-purity hydrogen (H2) from hydrocarbon reforming, membrane-based separation can be used. In this study, mixed matrix polymer membranes using metal–organic framework (MOF) nanoparticles are explored to overcome the permeability-selectivity trade-off of traditional polymeric membranes. Highly permeable and highly H2 selective MMM using ZIF-8, ZIF-67, and bimetallic ZIF-8/67 MOFs were fabricated via a non-solvent induced phase inversion method by incorporating an intermediate solvent evaporation step. MMMs with 5, 10, and 15 wt.% of nanofillers loadings were prepared and tested for single gas (H2, CO2, CH4, and N2) permeability at 1–2 bar pressures. MMMs permeability and selectivities exceeded the Robeson upper bound (2008) for H2/CO2 separation, demonstrating the potential for obtaining high-purity hydrogen at low pressures. H2/N2 selectivity of 43.4, H2/CO2 selectivity of 27.86 for and H2/CH4 selectivity of 31.36 were obtained. Analytical techniques such as XRD, FTIR, and DSC were used to explain the transport mechanism in the MMMs. The cross-sectional structure and morphology of MMMs were analyzed with field-emission scanning electron microscope (FESEM) to provide insights into the membrane's porous structure.
CFD Modeling of an Industrial Furnace Reformer and 3D Multi Scale Model for Packed Bed Reactor for Synthesis Gas Production
(AICHE, 2016) Kuncharam, Bhanu Vardhan Reddy
Synthesis gas (Syn gas) is used in many industrial applications such as Direct Reduction of Iron (DRI), Fischer-Tropsch synthesis, and also a source for environmental-friendly clean fuels and chemicals. In Midrex DRI process, syn gas is used to remove the chemically bound oxygen from raw iron-ore without melting. Syn gas is primarily produced from natural gas reforming in a large number of tubular packed bed reactors suspended in a furnace. Combustion of fuel takes places in the furnace supplying the requisite heat for the endothermic reforming reactions. The reactor tubes are made of special alloys and their failure due to uneven temperature or hotspots leads to the production loss or plant shutdown. Therefore, an accurate prediction of tube wall temperature is vital for preventing such tube failures. Computational Fluid Dynamics (CFD) is a powerful tool that can be used to simulate the turbulence, radiation and combustion in furnace reformer and the tube wall temperature is predicted without employing empirical heat transfer coefficients.
Content Contributions to the Indian Adaption of Transport Phenomena
(Wiley, 2021) Kuncharam, Bhanu Vardhan Reddy; Sheth, P.N.
Cost-Effective Catalytic Membranes for H2 Purification
(AICHE, 2012-04) Kuncharam, Bhanu Vardhan Reddy
Conventional membrane systems for high purity hydrogen production from hydrocarbons typically employ permselective Pd or Pd-alloy materials in conjunction with hydrocarbon reforming. Palladium is expensive, prone to poisoning by carbonaceous materials and suffers embrittlement over multiple thermal cycles. In the light of these challenges our research group is exploring the use of catalytic membranes to achieve hydrogen separation without relying upon costly and delicate permselective materials. In this presentation, we will review our work in the development of catalytic membranes for hydrogen extraction from fermentation liquors[1] and demonstrate the extension of this technique to hydrogen purification from reformate mixtures (H2, CO, CO2, H2O) using a catalytic membrane active for water-gas-shift reaction. Design simulations of this membrane system predict H2:CO permselectivities that are competitive to palladium membranes at a fraction of the materials cost. [1] B. Kuncharam and B.A. Wilhite. Design of a Composite Catalytic Membrane for Permselective Extraction of Hydrogen from Ethanol via Reaction and Diffusion.
Design of Cartridge-Based Ceramic Heat-Exchanger Microchannel Reformers for Process Intensification: Experiments and Simulations
(ACS, 2013) Kuncharam, Bhanu Vardhan Reddy
This paper details a combination of experimental and theoretical design analyses of a cartridge-based microchannel reformer system capable of integrating two or three separate reforming processes (reactant preheating, methanol steam reforming, and methanol combustion for autothermal operation) within a single monolithic device in a two-dimensional or radially layered distribution pattern. This system employs a ceramic microchannel cartridge with catalyst configurations tailored to enable stable autothermal operation over a broad range of reforming and combustion flow rates. Operation of the 25-channel prototype system coupling methanol combustion in air (13 mol % CH3OH and 17.3 mol % O2) with steam reforming of a dilute (2.6 mol %) methanol–water mixture at combustion and reforming overall flow rates of 300 standard cubic centimeters per minute (sccm) [gas hourly space velocity (GHSV) of 19 200 h–1] and 1800 sccm (GHSV of 14 400 h–1) achieved steam reforming hydrogen yields of ∼85%, corresponding to an overall hydrogen yield of 53%. When the outer layer of microchannels is employed for preheating of the reforming stream, the overall hydrogen yield was improved to 57%. A three-dimensional simulation of the microchannel reformer was constructed and validated through comparison to experimental data and then employed to predict the reformer performance using a concentrated (25 mol % CH3OH and 75 mol % H2O) steam reforming feed. Design simulations predict that hydrogen yields of ∼80% are achievable using the cartridge-based ceramic microchannel reformer.
Dynamic alterations of H3K4me3 and H3K27me3 at ADAM17 and Jagged-1 gene promoters cause an inflammatory switch of endothelial cells
(Wiley, 2021-09-14) Chowdhury, Shibasish; Majumder, Syamantak; Kuncharam, Bhanu Vardhan Reddy
Histone protein modifications control the inflammatory state of many immune cells. However, how dynamic alteration in histone methylation causes endothelial inflammation and apoptosis is not clearly understood. To examine this, we explored two contrasting histone methylations; an activating histone H3 lysine 4 trimethy- lation (H3K4me3) and a repressive histone H3 lysine 27 trimethylation (H3K27me3) in endothelial cells (EC) undergoing inflammation. Through computeraided reconstruction and 3D printing of the human coronary artery, we developed a unique model where EC were exposed to a pattern of oscillatory/disturbed flow as similar to in vivo conditions. Upon induction of endothelial inflammation, we detected a significant rise in H3K4me3 caused by an increase in the expression of SET1/ COMPASS family of H3K4 methyltransferases, including MLL1, MLL2, and SET1B. In contrast, EC undergoing inflammation exhibited truncated H3K27me3 level engendered by EZH2 cytosolic translocation through threonine 367 phosphorylation and an increase in the expression of histone demethylating enzyme JMJD3 and UTX. Additionally, many SET1/COMPASS family of proteins, including MLL1 (C), MLL2, and WDR5, were associated with either UTX or JMJD3 or both and such association was elevated in EC upon exposure to inflammatory stimuli. Dynamic enrichment of H3K4me3 and loss of H3K27me3 at Notchassociated gene promoters caused ADAM17 and Jagged1 derepression and abrupt Notch activation. Conversely, either reducing H3K4me3 or increasing H3K27me3 in EC undergoing inflammation atte- nuated Notch activation, endothelial inflammation, and apoptosis. Together, these findings indicate that dynamic chromatin modifications may cause an inflammatory and apoptotic switch of EC and that epigenetic reprogramming can potentially im- prove outcomes in endothelial inflammationassociated cardiovascular diseases.
Fabrication and testing of mixed matrix membranes of UiO-66-NH2 in cellulose acetate for CO2 separation from model biogas
(Wiley, 2022-10) Kuncharam, Bhanu Vardhan Reddy
Mixed Matrix Membranes (MMMs) of UiO-66-NH2 nanoparticles dispersed in Cellulose Acetate (CA) were prepared with filler loading of 2–20 wt%. MMMs were tested for the upgradation of model biogas (60%–40%) mixture of CH4/CO2 at a feed pressure of 2 bar and 1.5 bar. Detailed characterization of MMMs was performed with Fourier transform infrared spectroscopy (FTIR), Thermo-gravimetric analysis (TGA), Differential scanning calorimetry (DSC), and Field emission scanning electron microscopy (FESEM) to investigate the physical and thermal properties. MMMs formed are defects-free, voids-free, and without polymer rigidification, indicating a better filler polymer interface. MMMs showed improved CO2 permeability while retaining the CO2/CH4 selectivity. The 10 wt.% UiO-66-NH2/CA MMM showed optimum gas separation performance with CO2 permeability of 11 Barrer and CO2/CH4 selectivity of 10. The UiO-66-NH2/CA MMMs performed better when compared to the pure CA membrane. The experimental permeability and selectivity data were compared with the predicted data using Maxwell, Lewis–Nielsen, Higuchi, and Bruggeman's model.
High-throughput computational screening of metal organic frameworks (MOFs) for CO2 selective separations: trends, challenges, and future perspectives
(Elsevier, 2026-01) Kuncharam, Bhanu Vardhan Reddy; Gupta, Suresh
Efficient separation of CO2 from industrial gas mixtures such as CO2/N2, CO2/CH4, CO2/H2, and CH4/H2 is central to carbon capture, clean fuel production, and hydrogen purification. While metal organic frameworks (MOFs) offer an unparalleled design space for addressing these separations, the vast chemical and structural diversity of MOFs renders experimental evaluation impractical. High-throughput computational screening (HTCS), enabled by molecular simulations, has therefore emerged as a powerful approach to systematically evaluate and rank MOFs across multiple separation targets. This review critically examines HTCS methodologies for both adsorption and membrane-based separations, with a unified analysis of four industrially important gas systems. Further, emerging structure-property relationships to extract general design principles for CO2-selective separations are also highlighted. The review emphasizes that the choice of appropriate simulation inputs such as modelling the framework, force field and charge assignment significantly influence the screening and ranking of MOFs. CO2 typically exhibits strong electrostatic interactions with MOF surfaces, resulting in higher adsorption affinity compared to other gases, whereas the smaller and lighter H2 molecule displays rapid diffusivity. In kinetic separation, mixture diffusivity data is crucial in determining membrane performance. There exists a correlation between MOF structural features and their separation performance. In general, MOFs with narrow pores (3-5 Å) and moderate porosities (0.5-.75) perform better for CO2 separation. This review details the approaches adopted in HTCS of MOFs and the screening outcomes to guide future HTCS-driven MOF discovery.
Investigation of cellulose acetate and ZIF-8 mixed matrix membrane for CO2 separation from model biogas
(Taylor & Francis, 2022-11) Kuncharam, Bhanu Vardhan Reddy
The separation of CO2 from the biogas mixtures (CH4/CO2) is essential for biogas upgradation. However, polymer membranes used for CO2 separation exhibit low permeability. Mixed Matrix Membranes (MMMs) incorporating inorganic filler in the polymer enhance CO2 separation. In this work, bio-degradable cellulose acetate (CA) based MMMs with varying filler weight percentages (2–20 wt.%) of ZIF-8 were studied for the separation of CO2 from a model biogas (CH4/CO2) mixture. The MMMs were characterized by analysis of TGA and DSC for thermal stability and FTIR for alteration or formation of any new functional group. FESEM was done to evaluate the dispersion and interaction of ZIF-8 in the CA polymer matrix. Considering the economic aspect, the fabricated MMMs were tested for gas separation performance at reasonably lower feed pressure (1.5, 2 bar). MMM with 5 and 10 wt.% of ZIF-8/ CA MMMs showed the best performance with CO2 permeability of 9.65 Barrer and 9.5 Barrer, approximately two folds as compared to pure CA, and CO2/CH4 selectivity was 10.37 and 15.3. The experimental results were compared with the predicted gas permeation results determined using MMM transport predictive models, and found that the permeabilities were higher than the model predictions.
Investigation of mixed matrix membranes of graphene and acid-treated graphene fillers in cellulose acetate and polyetherimide polymers for CO2 separation from biogas
(Wiley, 2024-10) Kuncharam, Bhanu Vardhan Reddy
Gas separation membranes are crucial for upgrading biogas by separating carbon dioxide (CO2) from biogas, thereby enhancing its calorific value and reducing greenhouse gas emissions. This study aims to improve CO2/CH4 separation using mixed-matrix membranes (MMMs) by incorporating graphene (Gr) and acid-treated graphene (AGr) fillers in a cellulose acetate (CA) polymer matrix. Similarly, polyetherimide (PEI) MMMs were also prepared with Gr and AGr fillers to draw a comparison. Various characterization techniques, including Fourier transform infrared spectroscopy, differential scanning calorimetry, field emission scanning electron microscopy, Raman spectroscopy, and X-ray diffraction, were employed to investigate the structural and morphological properties of the membranes and fillers. Gas permeation tests using a model biogas mixture (40% CO2 and 60% CH4) revealed that the 0.1%AGr/CA membrane achieved the highest CO2 permeability of 43 Barrers, which is approximately 307% more than that of the pure CA membrane, and showed a CO2/CH4 selectivity of 14.80. The 0.5%Gr/PEI membrane demonstrated the best performance among PEI-based MMMs, with a CO2 permeability of 17.48 Barrers and a CO2/CH4 selectivity of 8.96. These results indicate that the incorporation of Gr and AGr significantly enhances the gas separation performance over pure CA and PEI membranes.
Investigation of ZIF-8, amine-modified ZIF-8 and polysulfone based mixed matrix membranes for CO2/CH4 separation
(Wiley, 2023-09) Kuncharam, Bhanu Vardhan Reddy
Membrane separation is one of the techniques used for biogas upgradation. Mixed matrix membranes (MMMs) are currently being explored to overcome the trade-off of selectivity-permeability inherent in polymer membranes used for gas separation. A significant challenge associated with MMMs is the poor polymer-metal–organic framework (MOF) filler interfacial compatibility, reducing the selectivity or permeability of gas. To address this issue, the present study focuses on the effect of the amine functionalization of ZIF-8 to enhance the CO2 gas permeation without reducing the CO2/CH4 selectivity. MMMs were fabricated using unmodified ZIF-8 and amine-modified ZIF-8 nanofillers dispersed in polysulfone at 5, 10, and 15 wt% loadings. MMMs were characterized by FTIR, DSC, TGA, and FESEM. X-ray diffraction and FTIR analysis was conducted to verify the amine modification of ZIF-8. Further, the performance of MMMs was tested with pure gasses (CO2 and CH4) and a model mixture of CO2 and CH4. In the mixed gas permeation test, the 10 wt% ZIF-8 MMM exhibited the highest CO2 permeability of 25.4 Barrers, while 15 wt% NH2-ZIF-8 MMM exhibited the highest selectivity of 13.5. Notably, the ZIF-8 MMMs demonstrated a 148% increase in CO2/CH4 selectivity, whereas the NH2-ZIF-8 MMMs exhibited a 155% increase compared to the pure polysulfone membrane.
Metal–organic framework (MOF) as adsorbents for hydrogen separation from steam methane reforming: an in-depth review
(Springer, 2025-10) Kuncharam, Bhanu Vardhan Reddy; Gupta, Suresh
Hydrogen (H2), acknowledged as a clean and advanced fuel, has attracted research focus for its production, purification, and energy generation in accordance with the Sustainable Development Goal (UN-SDG 7). H2 is produced by both fossil fuel (such as reforming, pyrolysis, gasification) and non-fossil fuel–based technologies (such as water electrolysis). Currently, fossil fuel–based hydrogen production predominates in meeting the current demands. However, hydrogen obtained through these methods is impure and requires purification before application. Metal–organic frameworks (MOFs) are emerging novel adsorbent materials that surpass conventional adsorbents owing to their favorable physicochemical characteristics and adaptability. This review elucidates the influences and correlations between MOF adsorbents and the performance of the pressure swing adsorption (PSA) process in the separation of H2 from steam methane reforming (SMR) off-gas. The PSA performance is dictated by the adsorbent’s properties and the operational parameters. The gas separation on MOF adsorbents occurs through equilibrium, kinetic, or size exclusion mechanisms. The H2 separation is largely governed by the van-der Waals interaction of various components of SMR off-gas with the MOF, and the gases interact in the order CO2 ≫ CH4 > CO > N2 > H2. It is noted that the MOF–gas interaction can be tuned by functioning MOFs with polar (e.g., -OH, NO2, SO3H) and non-polar functional groups (e.g., ester and alkanes). The operational parameters influence PSA performance indicators, and a general trend is seen among them. This review presents the critical analysis, summary, challenges, and outlook of the MOF-based PSA hydrogen separation, providing notable examples of MOFs reported.
A Multi-Scale Two-Dimensional Packed Bed Reactor Model for Catalytic Steam Methane Reforming
(AICHE, 2015-11) Kuncharam, Bhanu Vardhan Reddy
Steam methane reforming (SMR) is the primary source of synthesis gas (CO/H2) production for use in direct reduction of iron-ore. The endothermic and equilibrium-limited SMR reaction is carried out in multiple tubes packed with reforming catalyst. The models available in the literature for SMR packed bed reactor are one dimensional homogeneous and pseudo-homogeneous. The homogeneous model calculates the reaction at bulk fluid concentration and pseudo-homogeneous employs catalyst effectiveness factor. These models do not take into account the reaction and diffusion in the catalyst particle, and therefore predict inaccurate conversion and selectivity of products. This talk presents a steady state 2D multi-scale packed bed reformer model that takes into account the solid-gas phase mass and energy diffusional limitations along the reactor length. In lieu of using the catalyst effectiveness factor, mass and energy balance in the 3D catalyst particle is calculated and coupled with gas phase model. The gas phase model takes into account the axial and radial dispersion as well as finite solid-fluid mass and heat transfer coefficients; calculated using empirical correlations available in the literature. The pressure drop in the packed bed is calculated employing the Ergun equation and compared with the Eisfeld-Schnitzlein equation that takes into account the wall effects. The molar expansion during reaction is also taken into account using a differential equation for average molecular weight along reactor length. This talk presents the simulation results for different case studies employing the model. First, we will present the 2D non-isothermal model results and compare with 1D model results. Second, we will compare the simulation results using two different pressure drop equations. Finally, we will compare the results without taking into account the mole effects on velocity during reaction.
Multi-scale two-dimensional packed bed reactor model for industrial steam methane reforming
(Elsevier, 2020-04) Kuncharam, Bhanu Vardhan Reddy
A non-isothermal heterogeneous steady-state model was developed for a packed bed reactor for steam methane reforming employing a multi-scale approach. The model consists of two-dimensional fluid-phase mass and heat transport equations accounting for axial and radial dispersion in the reactor tube, as well as accounting for mass and heat transfer resistances at the fluid-solid phase boundary, calculated using empirical equations. Reaction, mass and heat transfer in the catalyst particle are directly coupled with the fluid-phase equations using a 1D pellet model, thus avoiding the use of a catalyst effectiveness factor for reaction. The performance of the packed-bed reactor is compared using three pressure drop equations: the Ergun equation which neglects wall effects and the Eisfeld-Schnitzlein and Di Felice-Gibilaro correlations which include them. This multi-scale model also accounts for the effects of temperature, pressure and molar change of gas species due to reaction on superficial velocity using a separate equation. The impact of neglecting these effects through simplified models is evaluated
Multi-scale two-dimensional packed bed reactor model for industrial steam methane reforming
(Elsiever, 2020-04) Kuncharam, Bhanu Vardhan Reddy
A non-isothermal heterogeneous steady-state model was developed for a packed bed reactor for steam methane reforming employing a multi-scale approach. The model consists of two-dimensional fluid-phase mass and heat transport equations accounting for axial and radial dispersion in the reactor tube, as well as accounting for mass and heat transfer resistances at the fluid-solid phase boundary, calculated using empirical equations. Reaction, mass and heat transfer in the catalyst particle are directly coupled with the fluid-phase equations using a 1D pellet model, thus avoiding the use of a catalyst effectiveness factor for reaction. The performance of the packed-bed reactor is compared using three pressure drop equations: the Ergun equation which neglects wall effects and the Eisfeld-Schnitzlein and Di Felice-Gibilaro correlations which include them. This multi-scale model also accounts for the effects of temperature, pressure and molar change of gas species due to reaction on superficial velocity using a separate equation. The impact of neglecting these effects through simplified models is evaluated.
Novel mixed matrix membranes with indium-based 2D and 3D MOFs as fillers and polysulfone for CO2/CH4 mixed gas separation
(RSC, 2025-01) Kuncharam, Bhanu Vardhan Reddy
To address the limitations of polymeric membranes, mixed matrix membranes for CO2 separation from biogas mixtures (CO2 and CH4) have been investigated utilizing various fillers. In this study, we investigated novel MMMs using 3D and 2D indium-based MOFs, MIL-68(In)–NH2 and In(aip)2, in a polysulfone polymer matrix. To confirm synthesis, both fillers were subjected to XRD and FTIR analysis, as well as FESEM characterization to assess their 2D and 3D structures. BET analysis revealed the pore size of MOFs. MMMs were characterized using XRD, FTIR, FESEM, and DSC to determine various membrane characteristics. MMMs were tested with CO2 : CH4 of 60 : 40 vol% to mimic the biogas mixture, and the CO2 permeability of 144 Barrer and 79.2 Barrer was obtained for 20 wt% In(aip)2/PSF membrane and 15 wt% MIL-68(In)–NH2/PSF membrane. The highest CO2/CH4 selectivities of 19.8 and 24.4 were obtained for 15 wt% MIL-68(In)–NH2/PSF MMM and 10 wt% In(aip)2/PSF MMM, respectively. The gas permeation findings of this study were compared with existing literature and long-term stability analysis was done to assess the performance of membranes for commercial standards.
Preparation, characterization, and CO2 permeation testing of cellulose acetate and polyimide blend membranes
(Wiley, 2023-11) Kuncharam, Bhanu Vardhan Reddy
Membrane-based CO2 separation is vital for various applications such as biogas upgradation. Polymer membranes are employed for CO2 separation in the industry. Polymer membranes have a trade-off between selectivity and permeability. Blending polymers is an emerging approach for altering the gas transport in the membranes. This work investigates the fabrication and characterization of blended biodegradable cellulose acetate (CA) with polyimide (PI). Thermal stability was characterized using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and functional groups were analyzed using Fourier transform infrared spectroscopy (FTIR). The morphology of membranes is analyzed using field-emission scanning electron microscope (FESEM). The blend membranes were tested for separation of CO2 from model biogas (CO2/CH4) at room temperature and a low feed pressure (∼1.5 bar). The CA:PI blend membrane composed of 93% CA and 7% PI showed CO2 permeability of 19.71 Barrer, approximately 206% greater than pure CA, and CO2/CH4 selectivity was 9.42. Experimental results are compared with literature on CA-based membranes.
A review of techniques to improve performance of metal organic framework (MOF) based mixed matrix membranes for CO2/CH4 separation
(Springer, 2022-02) Kuncharam, Bhanu Vardhan Reddy
The separation of carbon dioxide and methane is vital for biogas upgradation and natural gas sweetening applications. Membrane separation is one of the techniques used for CO2 and CH4 separation for biogas upgradation and natural gas sweetening owing to its energy efficiency, low capital cost, portable, and ease of operation. Polymer membranes and inorganic membranes have a trade-off relationship between permeability and selectivity. A new class of membranes known as Mixed Matrix Membranes (MMMs) is being explored to overcome this trade-off by dispersing inorganic fillers in the polymer matrix. However, the addition of filler poses new interfacial morphological difficulties, such as poor dispersion, very strong interaction between filler and polymer, and formation of voids. These challenges can be tackled by suitable choice of filler and polymer, functionalization of filler and polymer, polymer blending. The hybrid membranes separation process or use of two or more strategies can lead to the formation of defect-free membranes with improved separation performance. In this review article, we provide a concise literature review and analysis of the strategies for improving the transport properties of MMMs based on MOF as filter materials for CO2/CH4 separation.