Membrane Adsorption Research Articles

Ganglioside GM1 Drives Hemin and Protoporphyrin Adsorption in Phospholipid Membranes: A Structural Study.

Monosialoganglioside (GM1), a ubiquitous component of lipid rafts, and hemin, an integral part of heme proteins such as hemoglobin, are essential to the cell membranes of brain neurons and erythrocyte red blood cells for regulating cellular communication and oxygen transport. Protoporphyrin IX (PPIX) and its derivative hemin, on the contrary, show significant cytotoxic effects when in excess causing hematological diseases, such as thalassemia, anemia, malaria, and neurodegeneration. However, the in-depth molecular etiology of their interactions with the cell membrane has so far been poorly understood. Herein, the structure of the polymer cushion-supported lipid bilayer (SLB) of the binary mixture of phospholipid and GM1 in the presence of PPIX and its derivative hemin has been investigated to predict the molecular interactions in model phospholipid membranes. A high-resolution synchrotron-based X-ray scattering technique has been employed to explore the out-of-plane structure of the assembly at different compositions and concentrations. The structural changes have been complemented with the isobaric changes in the mean molecular area obtained from the Langmuir monolayer isotherm to predict the additive-induced membrane condensation and fluidization. PPIX-induced fluidization of phospholipid SLB without GM1 was witnessed, which was reversed to condensation with 2-fold higher structural changes in the presence of GM1. A hemin concentration-dependent linear condensing effect was observed in the pristine SLB. The effect was significantly reduced, and the linearity was observed to be lost in the mixed SLB containing GM1. Our study shows that GM1 alters the interaction of hemin and PPIX with the membrane, which could be explained with the aid of hydrophobic and electrostatic interactions. Our study indicates favorable and unfavorable interactions of GM1 with PPIX and hemin, respectively, in the membrane. The observed structural changes in both SLB and the underlying polymer cushion layer lead to the proposal of a molecule-specific interaction model that can benefit the pharmaceutical industries specialized for drug designing. Our study potentially enriches our fundamental biophysical understanding of neurodegenerative diseases and drug-membrane interactions.

A Label‐Free Multitechnique Approach to Characterize the Interaction of Bioactive Compounds with Biomimetic Interfaces

Extensive research has been conducted on biomimetic interfaces mimicking the complex and diverse microenvironment of cell membranes to gain insights into bioactive compound interactions and membrane biophysics modulation. The present study proposes an innovative approach that combines five prospective label‐free methodologies (derivative spectroscopy, synchrotron small‐ and wide‐angle X‐Ray scattering, attenuated total reflection–Fourier‐transform infrared spectroscopy, quartz‐crystal microbalance with dissipation, and surface plasmon resonance) to showcase their synergistic capabilities and complementarity in investigating drug–membrane interactions. This multitechnique approach combines the real‐time monitoring of the adsorption process under continuous flow conditions with the steady‐state perspective of this process. As a proof of concept, the interaction of three bioactive compounds (caffeine, testosterone, and diclofenac) with two biomimetic membrane interfaces (multistacked lipid bilayers and supported lipid bilayers) mimicking the more ordered lipid transient phases, with and without cholesterol (lo and so), that are responsible for a variety of membrane‐associated biological activities, is investigated. The biophysical effects of the bioactives are discussed using complementary data from real‐time and steady‐state experiments, including membrane adsorption and distribution, predicted location, and induced changes in order and fluidity, encompassing bilayer thickness, hydration, and area per lipid molecule.

Selective adsorption in ion exchange membranes: The effect of solution ion composition on ion partitioning

Electrodialysis is a water desalination technology that enables selective separation of ions, making it a promising solution for sustainable water reuse. The selectivity of the process is mainly determined by the properties of ion exchange membranes that can vary depending on the composition of ions in water, such as water uptake and charge density. In this work, we studied selective adsorption of Na+ and K+ ions in various ion exchange membranes considering the effect of solution ion composition on membrane water volume fraction. For that purpose, we conducted membrane adsorption experiments using solutions with Na+ and K+ ions with different ion compositions including Li+, Ca2+ or Mg2+ ions at different concentrations (0.001 – 0.25 M). The experiments showed that with the total ion concentration and the amount of divalent ions in solution, the membrane water volume fraction decreases while the selective adsorption of the smaller (hydrated) K+ ions over the Na+ ions in the membrane increases. We developed a theoretical framework based on Boublik-Mansoori-Carnahan-Starling-Leland (BMCSL) theory to describe the effect of membrane water volume fraction on selective adsorption of the ions by including volumetric effects, such as size exclusion. The developed framework was used to describe ion partitioning results of the membrane adsorption experiments. In addition, the effect of solution ion composition on selective ion removal during electrodialysis operation was evaluated using experimental data and theoretical calculations. The results of this study show that considering volumetric effects can improve the ion partitioning description in ion exchange membranes for solutions with various ion compositions.

Enhanced removal of tetracycline by sandwich layer composite membrane based on the synergistic effect of photocatalysis and adsorption

Environmental pollution has become increasingly serious, especially the abuse of tetracycline (TC) antibiotics, which has brought serious problems to human life. Therefore, the residual TC in the environment has become an urgent problem to be solved. To improve the efficiency of TC wastewater purification and solve the problem of powder material recovery during photocatalysis, a sandwich layer photocatalytic composite membrane with catalytic/adsorption synergistic effect was prepared in this study. The first layer of the composite membrane is composed of a polyether sulfone (PES) membrane loaded with UiO-66-NH2/Bi2.15WO6 (UN/BWO) photocatalyst (named as UN/BWO@PES), the middle layer is a support layer composed of polyester/cotton fabric, and the lower layer is composed of a calcium alginate/diatomite (CA@DE) membrane with adsorption for TC. Under dark conditions, the rejection percentage of TC by sandwich composite membrane (M4.5 D0.02-3) can reach 50.81%, while under light conditions, the removal efficiency of TC by M4.5 D0.02-3 can reach 93.94%. Even after four cycles, the removal percentage of TC by M4.5 D0.02-3 can still reach 87.10%. Therefore, the visible light responsive photocatalytic composite membrane developed in this study has dual advantages of photocatalysis and membrane adsorption filtration, and has enormous application potential in wastewater treatment, which can minimize membrane pollution and improve the reusability of photocatalysts.

Biowaste-alkaline lignin and GO integrated polysulfone ultrafiltration membrane fabrication for Pb2+ and Eosin Y dye removal

The textile industry uses a variety of lead compounds, including lead acetate for textile dyeing, lead chloride for lead salt manufacture, and lead molybdate for pigments. Furthermore, Eosin Y, a water-soluble red dye, is commonly used in textile dyeing and ink production. The presence of Eosin Y dye and lead metal ions in textile industry effluents is prevalent. Integrating adsorbent nanofillers into the membrane matrix serves a dual purpose of membrane filtration and adsorption functionalities. In this study, Lignin/GO incorporated polysulfone composite membranes were fabricated with the phase inversion method and with PEG 6000 as a pore-forming agent. Zeta potential, pure water flux, mechanical strength, and hydrophilicity of the membranes were all improved by the integration of lignin and GO into the membrane matrix. Filtration operations were carried out using an aqueous solution containing both lead (Pb) and Eosin Y dye. Additionally, the influence of their electrostatic interactions on membrane fouling and the regeneration process was examined. The electrostatic interaction, specifically the linking effect between Pb2+ ions and negatively charged Eosin Y molecules, formed larger Eosin-Pb complexes. This led to an enhanced Pb2+ removal through membrane filtration. During the second filtration cycle, the membrane, comprising 0.75 wt% lignin and 0.75 wt% GO, achieved 100 % removal of Pb2+ ions and an 81 % rejection of Eosin Y. A Pb2+ adsorption study was conducted using the optimized lignin/GO membrane. The adsorption process was investigated through Langmuir and Freundlich isotherms exhibiting a superior fit and assured R2 values of 0.977 and 0.994, respectively. According to the isotherm data the adsorption process involves multilayer physisorption. The developed Lignin/GO-incorporated polysulfone composite membranes hold the promise for tackling issues in a variety of domains, including water treatment and biomedical applications, demonstrating versatility and ability to make positive impacts across industries.

Polyelectrolyte electrostatically self-assembled modified porous polyacrylonitrile nanofibers as adsorbents for anionic dye removal

Herein, we chose PAN with good sunlight and weather resistance and easy surface modification as the electrospinning material to prepare the PAN nanofiber membrane. Then the surface modification of the obtained PAN fiber membrane was carried out sequentially by alkali hydrolysis and acid neutralization to make the surface of the fiber membrane negatively charged. Finally, the positively charged polyelectrolyte PAH on the surface was selected as the functional material, and a simple and environmentally friendly electrostatic self-assembly method was adopted to modify the prepared PAN nanofiber membranes labeled as PAN@PAH. This treatment effectively increased the storage space and adsorption groups of the fiber membranes, which led to a significant increase in the removal ability of anionic dyes in wastewater. In particular, the PAN@PAH nanofiber membrane adsorbed 439.66 mg/g of methyl orange and 946.83 mg/g of Congo red, which showed better adsorption capacity than many other membranes reported in the literature. Moreover, the adsorption capacity of PAN@PAH remained at 90.19 % after eight adsorption-desorption cycles. The preparation method and modification strategy of this membrane adsorbent provides new ideas and methods for the removal of other anionic dyes.

Performance investigation on a self-powered microbial pollutant adsorption cell with N-LAC/PVDF cation exchange membrane

A high-efficiency, self-powered microbial pollutant adsorption cell with an N-LAC/PVDF cation exchange membrane was proposed to remove metal ions and organic dyes in high-salt wastewater. Nitrogen-doped alkali lignin (N-LAC) was synthesized using chitosan nanoparticles (CS) and alkali lignin (AL) using a blending method. The N-LAC/PVDF cation exchange membrane was prepared by chemically grafting polyvinylidene fluoride (PVDF). With modification, hydroxyl, carboxyl, carbonyl, and other hydrophilicity groups were introduced into the cation exchange membrane. The addition of N-LAC improved the membrane's hydrophilicity and adsorption capacity. FITR and SEM, respectively, characterized the surface morphology of the exchange membrane. The result showed that the contact angle reached 74.89° when the amount of N-LAC was 1 wt.%, and the desalination efficiency was 93.5 %, which increased by 70 %. The adsorption capacity of organic dye Pb and metal ion MB was 91 % and 94 %, respectively, showing an increase of 31.9 % and 43.5 %.

Fabrication optimization of polyethersulfone adsorptive mixed matrix membrane for enhanced dynamic methylene blue removal: Response surface methodology approach

AbstractIn the present study, the polyethersulfone (PES)/graphene oxide (GO)/polyethylene glycol 200 (PEG‐200) adsorptive mixed matrix membranes (AMMMs) were fabricated using a non‐solvent induced phase inversion method. According to the design of experiments using response surface methodology (RSM), PES concentration (15, 17.5, and 20%), PEG‐200 concentration as a pore former additive (0.5, 2.5, and 4.5%), and GO nanosheet loading percent (0, 0.5, and 1%) were varied during fabrication. A green solvent, dimethyl sulfoxide, was used as an alternative to conventional solvents, while it exhibited better membrane performance. Methylene blue (MB) removal was optimized in PES AMMM synthesis using RSM. Attenuated total reflectance Fourier transform infrared spectroscope confirmed the presence of GO functional groups in the optimum membrane. Scanning electron microscopy analysis revealed the optimum membrane was thicker than the neat membrane and atomic force microscopy analysis demonstrated higher surface roughness. The membranes hydrophilicity increased, with a decrease in water contact angle from 61.1 ± 0.2° (neat PES) to 54.4 ± 0.9° (optimal membrane). Pure water flux of 524.8 L m−2 h−1 and MB rejection of 97.46% were obtained for the optimum membrane. Furthermore, the optimum PES AMMM demonstrated a greater dynamic adsorption capacity in comparison to the unmodified PES membrane.Highlights The optimization of the polyethersulfone (PES) adsorptive mixed matrix membranes (AMMM) for methylene blue removal was performed utilizing the response surface methodology. The calculation of the dynamic adsorption capacity (DAC) was performed through the breakthrough curves. The integration of graphene oxide into the AMMM resulted in an enhanced DAC of the AMMM. The PES AMMM performance is based on Donnan electrostatic exclusion.

Harnessing deep eutectic solvents for upcycling waste membranes into high-performance adsorbents and energy storage materials

Polymer membranes waste management across the globe is a great concern due to the lack of advancement in upcycling methods. Herein, waste polysulfone (W-PSF) membranes, an emerging environment threat, have been converted to multi-functional carbon materials via green method using choline chloride:FeCl3 (CC:FeCl3) based deep eutectic solvent (DES) systems through solvothermal reaction followed by pyrolysis at 900 °C. The optimized material (Fe-WPSF-01) showed excellent adsorption capacity towards Malachite green (MG), Congo red (CR), Amoxicillin (Amo), and Bisphenol-A (BPA) with 515, 407, 216, and 322 mg/g of adsorption capacity, as calculated from the well-fitted Langmuir isotherm. Further, an easy-to-use adsorptive membrane filtration method was established to investigate the robustness of Fe-WPSF-01 in removing the above pollutants in continuous flow method. The resultant flux rate was 700–815 L.m−2.h−1 with rejection rates of 99, 98, 92, & 98 % for MG, CR, Amo, & BPA, respectively. Besides, the material showed recyclability for up to 10 cycles with 92.1 & 81.2 % of rejection rates for MG and Amo. After the potential usage of carbon material in adsorption studies, secondary materials were again pyrolyzed to use as an electrode in supercapacitors with a specific capacitance of 215 F/g at a current density of 0.1 A/g. Electrode showed capacity retention of 97.51 % even after about 20,000 cycles at an increased current density of about 5 A/g. Thus, a potential sustainable approach of upcycling the W-PSF membranes for energy and environmental applications are well-presented in this work.

Properties and Evaluation of Functionalized Mixed Membrane Adsorbents for the Adsorption of Vanillic Acid from Palm Oil Waste

Identifying factors that can improve the ability of mixed matrix membrane (MMM) adsorbents to isolate phenolic chemicals from palm oil waste is a major challenge. This study prepared a mixed matrix membrane with improved efficiency using a quaternary doping solution and a hydroxyapatite (HAp) filler and denoted as modified mixed matrix membrane (MMMHAp). Prior to use, HAp powder obtained from eggshells calcined at different temperatures was evaluated as an absorbent for the desired phenolic compounds. All the prepared HAp and MMMHAp powders were evaluated for their properties by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-ray diffraction (XRD). For this study, vanillic acid was selected as a phenolic chemical because it is widely used in the pharmaceutical, biomedical and food industries. The optimal adsorption and vanillic acid isolation from crude palm oil samples by MMMHAp occurred using an acetate buffer solution with a pH of 8. The data from the equilibrium adsorption study were also in agreement with the Freundlich isotherm, as the R2 value was 0.9900 suggesting heterogeneous adsorption of vanillic acid on the surface of MMMHAp. The kinetic adsorption study clearly shows a pseudo-second-order fit (R2=0.9992), suggesting that chemisorption occurs between the adsorbed substance and the adsorbent. The modified membrane (MMMHAp) has characteristics of its finger-like structures is more elongated and connected to the porous layer, indicating that the incorporation of hydroxyapatite nanoparticles into the membrane enhances the adsorption of vanillic acid from real sample and has the highest adsorption capacity of 170.8 mg/g. These results show that this improved MMMHAp can be developed and used for waste utilization to obtain useful materials.

Polymer of Intrinsic Microporosity Enabled pH-Responsive Adsorptive Membrane: Selectivity and Mechanism

Polymer of Intrinsic Microporosity Enabled pH-Responsive Adsorptive Membrane: Selectivity and Mechanism

Highly selective recovery of palladium using innovative double-layer adsorptive membranes

Palladium (Pd) recovery from secondary resources is urgently needed to meet the rising demands for precious metals for sustainable development and environmental protection. To achieve the goal of simple, efficient, and selective recovery of precious metal Pd, we reported an innovative strategy that utilized a double-layer adsorptive membrane based on polydopamine (PDA) modification and polymethacryloxyethyltrimethyl ammonium chloride (PDMC) grafting. The adsorption results suggested that the adsorptive membrane exhibited an excellent adsorption capacity of 61.5 mg g−1 towards Pd(II) at pH 2.0 and the adsorption capacity remained stable after six cycles. Moreover, the adsorption processes of Pd(II) were fitted to pseudo second-order kinetic models and the Langmuir isotherm models. Density functional theory (DFT) simulation, and FTIR, XPS analysis indicated the adsorption mechanisms were ion exchange from the PDMC layer and chelation and ion exchange from the PDA layer. In the presence of other metal ions (Ni(II), Cu(II), Zn(II), Ca(II), Mg(II), K(I) and Na(I)), the separation factor of adsorptive membrane for Pd(II) was in the range of 50–529. The remarkable selectivity was due to the mechanism of the combination of electrostatic attraction and coordination interaction to Pd(II) while the electrostatic repulsion to other metal cations. Furthermore, membrane filtration results suggested that Pd(II) was effectively adsorbed and rejected and the leakage risk could be reduced by dual adsorption from the double-layer membrane. This study not only offers an innovative strategy to precisely and effectively recover Pd(II) and other platinum group metals, but also provides valuable insights for the future implementation of adsorptive membranes in recycling low-concentration wastewater in an efficient and friendly way.

Interfacial modification of hydrogel composite membranes for protein adsorption with cavitands as nano molecular containers

Protein adsorption is of great significance for bioengineering, biomedicine, drug release, etc. Herein, poly-N-isopropylacrylamide (PNIPAm) and polyethylene glycol diacrylate (PEGDA) based hydrogel materials were used to introduce self-synthesized cavitands with pore cage structures and hydrophobic characteristics to construct high-efficiency hydrogel composite membrane (HCM) for the adsorption of bovine serum albumin (BSA). The hydrophobic cavitand cage can improve the interfacial polymerization process by impacting the monomer diffusion and then modifying the interface properties of the hydrogel molecular network, which is validated by the molecular dynamic simulation. The adsorption mechanism can be interpreted as the reorganization of the polymer pores using the cavitands, and hence the surface charge and hydrophobic property consequently changed, which is consistent with the measurement results as well as validated by the molecular dynamic simulation. Thus, the fabricated HCM exhibits good structural stability, thermal stability, and robust BSA adsorption performance. The results indicated that the developed HCM materials can be promising candidates for effective protein separation.

The analytic hierarchy process method to design applicable decision making for the effective removal of 2-MIB and geosmin in water sources

Numerous utilities encounter issues with taste and odor that alter the public’s impression of the safety of drinking water. The creation of certain components in water naturally due to global climate change is another source of taste and odor components, in addition to industrial emissions. Geosmin and 2-methylisoborneol (2-MIB), both of which are generated by blue-green algae and actinomycetes, are two substances that contribute to the musty and earthy smells in drinking water sources. Unfortunately, current conventional treatment plants only partially remove 2-MIB and geosmin. Therefore, to protect the environment and public health, more up-to-date or optimized treatment methods should be applied to outdated treatment facilities. Best treatment practices, evaluation standards, and decision-making approaches, however, are still shrouded in mystery. The goal of this study was to identify the most effective treatment options for 2-MIB and geosmin. By using the analytical hierarchy process (AHP), a total of 22 assessment criteria were found and prioritized. A thorough literature search led to the identification of potential treatment options, and their effectiveness was evaluated. These options and priority rankings were decided upon using AHP in the decision-making process. Advanced oxidation techniques came out on top in the final priority ranking, followed by membrane filtering, adsorption, oxidation, hybrid processes, and traditional treatment methods. The applied analytical decision techniques may also be used to choose the optimal treatment options, even though the results are particular to 2-MIB and geosmin.

Preparation of Protein A Membranes Using Propargyl Methacrylate-Based Copolymers and Copper-Catalyzed Alkyne-Azide Click Chemistry.

The development of convective technologies for antibody purification is of interest to the bioprocessing industries. This study developed a Protein A membrane using a combination of graft polymerization and copper(I)-catalyzed alkyne-azide click chemistry. Regenerated cellulose supports were functionalized via surface-initiated copolymerization of propargyl methacrylate (PgMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA300), followed by a reaction with azide-functionalized Protein A ligand. The polymer-modified membranes were characterized using attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), gravimetric analysis, and permeability measurements. Copolymer composition was determined using the Mayo-Lewis equation. Membranes clicked with azide-conjugated Protein A were evaluated by measuring static and dynamic binding (DBC10) capacities for human immunoglobulin G (hIgG). Copolymer composition and degree of grafting were found to affect maximum static binding capacities, with values ranging from 5 to 16 mg/mL. DBC10 values did not vary with flow rate, as expected of membrane adsorbers.

The Design of PAN-Based Janus Membrane with Adjustable Asymmetric Wettability in Wastewater Purification.

In this paper, an environmentally friendly polyacrylonitrile-based (PAN-based) composite membrane with a Janus structure for wastewater treatment was successfully fabricated. To achieve the optimum adsorption of PAN-based Janus composite membrane, the asymmetric wettability was regulated through electrospinning, resulting in TiO2 modifying PAN as the hydrophilic substrate layer, and PCL gaining a different thickness as the hydrophobic layer. The prepared Janus composite membrane (PAN/TiO2-PCL20) showed excellent oil/water separation performance for diverse surfactant-stabilized oil-in-water emulsions. For n-hexane-in-water emulsion, the permeate flux and separation efficiency reached 1344 L m-2 h-1 and 99.52%, respectively. Even after 20 cycles of separation, it still had outstanding reusability and the separation efficiency remained above 99.15%. Meanwhile, the PAN/TiO2-PCL20 also exhibited an excellent photocatalytic activity, and the removal rate for RhB reached 93.2%. In addition, the research revealed that PAN/TiO2-PCL20 possessed good mechanical property and unidirectional water transfer capability. All results indicated that PAN/TiO2-PCL20 with photocatalysis and oil/water separation performance could be used for practical complex wastewater purification.

PREPARATION AND CHARACTERIZATION OF ZINC CROSSLINKED CHITOSAN MEMBRANE AS AN EFFECTIVE ADSORPTION MATERIAL FOR AMOXICILLIN IN PHARMACEUTICAL WASTEWATER

This study aims to synthesize a zinc crosslinked chitosan (Chi/Zn) membrane as an adsorbent for amoxicillin in pharmaceutical wastewater. The Chi/Zn membranes were prepared over 14 hours at 50 °C with varying chitosan and zinc concentrations. FTIR analysis confirmed successful crosslinking by identifying hydroxyl (O-H), carbonyl (C-O), and amine groups (NH2), along with N-Zn and O-Zn interactions. XRD analysis indicated an amorphous structure, while SEM revealed rough, uneven surfaces. The highest adsorption capacity of a chitosan membrane occurs at a concentration of 60 mg/L. At this concentration, the pure chitosan membrane's adsorption effectiveness and capacity are 42.2% and 42.2 mg/L, respectively. The Chi/Zn membrane adsorbed amoxicillin with an adsorption efficiency of 58.86% with an adsorption capacity of 58.86 mg/g. Thus, it can be said that the chitosan/Zn membrane is quite effective in being applied as an amoxicillin adsorbent in pharmaceutical waste.

Gas transport mechanisms through MOF glass membranes

The study provides an in-depth study on the gas adsorption and transport behaviors of MOF glass membranes for the first time. Temperature dependance of gas permeability, adsorption coefficients and diffusion coefficients between 298 ​K and 313 ​K for TIF-4 and ZIF-62 glass membrane were evaluated. The CO2 permeability was dominated by the adsorption process, while CH4 transport was mainly driven by the activated diffusion. Further, the MOF glass membranes exhibited significant entropic selectivity in adsorption, along with notable enthalpic selectivity in diffusion.

Enhanced Dye Adsorption and Bacterial Removal of Magnetic Nanoparticle-Functionalized Bacterial Cellulose Acetate Membranes

Enhanced Dye Adsorption and Bacterial Removal of Magnetic Nanoparticle-Functionalized Bacterial Cellulose Acetate Membranes

On assessing the carbon capture performance of graphynes with particle swarm optimization.

Tackling climate change is one of the greatest challenges of current times and therefore the development of efficient technologies to limit anthropogenic emissions is of utmost urgency. Recent research towards this goal has alluded to the use of carbon-based solid sorbents for carbon capture. Graphynes (GYs), an interesting class of porous carbon membranes, have recently proven their potential as excellent membranes for gas adsorption and separation. Herein, we explored the CO2 and N2 adsorption characteristics and CO2/N2 selectivities of a class of GYs, namely γ-GY-1, γ-GY-2 and γ-GY-4. We investigated the putative global minimum geometries of adsorbed unary (n = 2-10) and binary (n : m; n, m ∈ [1, 8]) clusters of CO2 and N2 by employing a stochastic global optimization method called particle swarm optimization in conjunction with empirical intermolecular force field formulations. The intervening interactions are modeled using various pairwise potentials, including Lennard-Jones potential, improved Lennard-Jones potential, Buckingham potential and Coulombic potential. The binding energies for both unary and binary clusters are highest for adsorption on γ-GY-1, followed by γ-GY-2. The putative global minimum geometries suggested that N2 molecules preferred binding over the pore centres while CO2 molecules showed higher clustering propensity than any binding site preference. The predicted interaction energies suggested higher selectivity for CO2 over N2 for all the three γ-GYs.