Ideal Selectivity Research Articles

Mixed matrix membranes containing Cu-based metal organic framework and functionalized ionic liquid for efficient NH3 separation

Membranes that both have high gas permeability and selectivity is still challenging. Aiming to efficiently separate and purify ammonia-containing gases, this work constructed a novel ternary mixed matrix membranes (MMMs) by introducing functionalized ionic liquid ([Bim][NTf2]) and Cu-based metal organic framework (CuBTC). It was proved that the interaction networks consisted of hydrogen bonding and electrostatic interactions are formed in the IL-based MMMs, leading to the improved compatibility, decreased crystallinity and amorphous morphology. The ammonia separation performance was evaluated through pure gases and mixed gases. The PCu3-IL100 MMM exhibits great ideal selectivities (αNH3/N2 = 530.1 and αNH3/H2 = 94.2) and optimal NH3 permeability up to 3680.0 barrer, which is 260% and 129% higher than the pristine Pebax membrane and the PCu3 MMM, respectively. The improving NH3 separation performance is attributed to the synergistic interaction of hydrogen bonding and Lewis acid-base between IL-based MMMs and NH3 molecules, significantly increasing NH3 solubility coefficient and solubility selectivity. The IL-based MMMs also show exceptional NH3 mixed separation performance and long-term operation stability.

Investigating the State of Skin Layer of Asymmetric Polyethersulfone (PES) ‐ Zeolitic Imidazole Framework‐8 (ZIF‐8) Mixed Matrix Gas Separation Membranes and Its Effect on Gas Separation Performance

AbstractAsymmetric and dense polyethersulfone (PES) and PES/ZIF‐8 (Zeolitic Imidazole Framework‐8) membranes were produced by nonsolvent induced phase inversion and solvent evaporation, respectively. The skin layer on the asymmetric membranes was prepared intentionally thick to observe the distribution of ZIF‐8 and interfacial voids between ZIF‐8 and PES, and to compare the state of ZIF‐8 in the asymmetric membranes with that of in dense membranes prepared by solvent evaporation. All asymmetric membranes were prepared only by wet phase inversion to eliminate the effect of solvent evaporation on the skin layer morphology. For this purpose, the effect of composition of solvent and nonsolvent bath, ZIF‐8 percentage and particle size was investigated. The skin layer on asymmetric and dense membranes prepared by SE (solvent evaporation) had very similar morphologies, CO2/CH4 and H2/CH4 ideal selectivities, however, the single gas permeabilities through asymmetric membranes were higher. This was attributed to the influence of ZIF‐8 on the structure of continuous polymeric phase.

Selection-diffusion-selection mechanisms in ordered hierarchically-porous MOF-on-MOF: ZIF-8 @NH2-MIL-125 for efficient CO2 separation

To promote CO2/N2 selectivity of MOF (metal organic framework)-on-MOF hybrids, ZIF-8 (Zeolitic imidazolate frameworks-8) @NH2-MIL-125 (Materials of Institute Lavoisier-125) with ordered hierarchically-porous structures were originally fabricated and in-situ loaded as nanofillers in mixed matrix membranes (MMMs) to efficiently separate CO2 from N2 based on selection-diffusion-selection mechanism. The guest ZIF-8 nanoparticles (theoretical pore size = 0.34 nm) were uniformly grown on surfaces of the host NH2-MIL-125 nanoparticles and acted as molecular sieves owing to its small pore size, which kept larger N2 molecules (theoretical kinetic diameter = 0.36 nm) out and allowed smaller CO2 molecules (theoretical kinetic diameter = 0.33 nm) to pass through, while the host NH2-MIL-125 with relatively large pores (theoretical pore size = 0.60 nm) provided low-resistance channels for rapid CO2 transfer. The CO2/N2 adsorption selectivity of ZIF-8 @NH2-MIL-125 heterostructures exhibited 12 % and 300 % higher than that of NH2-MIL-125 and ZIF-8, respectively. The Pebax-based MMMs loaded with ZIF-8 @NH2-MIL-125 nanofillers had an increased CO2/N2 ideal selectivity by 42 % and 61 % compared to that of Pebax@NH2-MIL-125 and Pebax@ZIF-8, respectively.

CO2-Selective mixed matrix membranes of bimetallic Zn/Co-ZIF vs. ZIF-8 and ZIF-67

Bimetallic metal–organic frameworks (MOF) have received growing attention in several fields for gas separation/adsorption, energy storage and catalysis because of their synergic effect and enhanced properties compared to their parent structures. Here, we first report on a facile and low cost direct synthesis of solid solution of bimetallic Zn/Co-ZIF and its monometallic counterparts, ZIF-8 and ZIF-67 at room temperature. Zn/Co-ZIF showed higher pore volume and BET surface area than their parents, homogeneous distribution of metals within the framework and a slightly higher Zn-rich external surface. Next, mixed matrix membranes (MMM) of Zn/Co-ZIF, ZIF-8 and ZIF-67 based 6FDA-ODA polyimide were fabricated with different content (3–10 %wt) via a wet approach using undried MOF for CO2/CH4 single and mixed gas (10:90 vol%) separation application to determine the effect of the metal center on the gas transport properties. While Zn/Co-ZIF (10 wt%)/6FDA-ODA had the highest CO2/CH4 selectivity (39.8) and CO2 permeability (45.8 Barrer) compared to the MMM of ZIF-8 (PCO2 = 41.6 Barrer, SCO2/CH4 = 36.1) and ZIF-67 (PCO2 = 26.2 Barrer, SCO2/CH4 = 26.3) at the same concentration, the best performance was observed for Zn/Co (7.5 wt%)/6FDA-ODA MMM with 104% and 41% increase in CO2 permeability up to 44.2 Barrer and CO2/CH4 ideal selectivity to 45.1, compared to the neat polymer, respectively.

Experimental Investigation of Adsorption and CO2/CH4Separation Properties of 13X and JLOX-500 Zeolites during the Purification of Liquefied Natural Gas

Efficient adsorbents are critical to the purification of liquefied natural gas (LNG) by the adsorption method. In this study, the physiochemical properties of JLOX-500 and 13X were examined. JLOX-500 with more Al content had a more compact unit cell, a larger surface area and pore volume, a smaller average pore size, and more microchannels on the surface than 13X. The separation performance of the two adsorbents was evaluated by the adsorption experiment. The CO2 adsorption capacity of JLOX-500 was higher than that of 13X, while the equilibrium and ideal selectivity and separation factor of CO2/CH4 were also larger for JLOX-500. Especially in dynamic adsorption, the CO2 adsorption capacities at 50 ppm of the gas mixture at the outlet were 3.46 and 1.64 mmol/g for JLOX-500 and 13X, respectively. The adsorption heats of CO2 and CH4 on JLOX-500 were 40.50 and 18.77 kJ/mol, whereas these values were 31.49 and 18.50 kJ/mol for 13X, respectively. A better separation performance for JLOX-500 was observed because of fewer binders and a lower Si/Al ratio (1.34). The Toth adsorption isotherm model described best the experimental data. According to the results of this study, JLOX-500 was a more efficient adsorbent used in purification for LNG production at high pressure with low CO2 concentration.

A Low-Cost Porous Polymer Membrane for Gas Permeation.

In this work, an efficient technique was used to produce porous membranes for different applications. Polyethylene (PE) was selected for the matrix, while corn starch (CS) was used to create the porous structure via leaching. The membranes were produced by continuous extrusion (blending)–calendering (forming) followed by CS leaching in a 20% aqueous acetic acid solution at 80 °C. A complete characterization of the resulting membranes was performed including morphological and mechanical properties. After process optimization, the gas transport properties through the membranes were determined on the basis of pure gas permeation including CH4, CO2, O2, and N2 for two specific applications: biogas sweetening (CH4/CO2) and oxygen-enriched air (O2/N2). The gas separation results for ideal permeability and selectivity at 25 °C and 1.17 bar (17 psi) show that these membranes are a good starting point for industrial applications since they are low-cost, easy to produce, and can be further optimized.

Thermal rearrangement in thermal cascade reaction polymers via ortho-carbonate ester functionalization of polyimides and their gas separation performance

Thermal Rearrangement Polymers have a strong potential regarding to gas separation membrane materials, especially for the purification of methane containing gas streams, due to their inter-connected bottleneck-type pores. However, most TR polymers reveal high permeabilities and high conversions only at high temperatures of 450 °C. Our study demonstrates a method to enhance the permeability at lower annealing temperatures by tailoring the thermally triggered decomposition and reaction cascade via modification and temperature protocol. In this study a set of seven carbonate ester modifications was prepared and thermo-analytically studied by means of DSC and TGA-FTIR on-line analysis combined with structure determination methods and quantum mechanical simulations. Two decarboxylative alkyl-transfer reaction mechanisms were formulated for the decomposition reaction of the carbonate ester group. A correlation of the size and branching of the carbonate ester connected alkyl group and its effect on the film properties and gas separation performance was studied. High polyimide to polybenzoxazole conversions were determined for the modified polymers and a 2008 upper bound performance was obtained for all materials, after annealing at 400 °C. Furthermore, the ethyl carbonate ester (ECO3PI-1) polymer entered the target zone above an ideal selectivity of CO2/CH4 of 30 after aging, making it an attractive membrane material.

Mechanism of selectivity control for zeolites modified with organic monolayers

The adsorptive separation of C3H6 and C3H8 gases using molecular sieves is a challenging process due to the similarity in molecular sizes for the two molecules. In this work, we report that organic phosphonic acid (PA) monolayers on zeolites significantly enhanced the ideal selectivity of C3H6/C3H8 adsorption by changing the diffusion mechanism based on the properties of the alkyl tail. With an n-octadecylphosphonic acid (ODPA) coating on zeolite 5A, the kinetic selectivity of C3H6/C3H8 was initially >8 at 25 °C, whereas for uncoated 5A, it was limited to ∼1.2. Kinetic modeling showed that in ODPA-coated 5A, the diffusion of C3H6 and C3H8 was limited by the PA monolayer at the external surface of the zeolite. In contrast, for uncoated 5A, it was controlled by the pore channels, so that the enhanced kinetic selectivity from 5A-ODPA was related to a different limiting transport mechanism. The kinetic selectivity was not temperature sensitive in the range of 25–150 °C in 5A-ODPA as the diffusion activation energies of C3H6 and C3H8 were both small. Modification of 5A with other PAs also increased the kinetic selectivity. Coating with n-butylphosphonic acid yielded lower kinetic selectivity than ODPA, ostensibly due to its shorter alkyl tail. Coating with tert-butylphosphonic acid, a sterically bulky ligand, decreased kinetic selectivity still further. However, methylphosphonic acid, which partially penetrated the near-surface region of the zeolite, severely lowered the diffusion rates. The use of organic films may enable rational design of selective adsorbents based on providing gas-specific resistance at the pore entrance.

Pore Structure and Gas Diffusion Features of Ionic Liquid-Derived Carbon Membranes

In the present study, the concept of Ionic Liquid (IL)-mediated formation of carbon was applied to derive composite membranes bearing a nanoporous carbon phase within their separation layer. Thermolytic carbonization of the supported ionic liquid membranes, prepared by infiltration of the IL 1-methyl-3-butylimidazolium tricyanomethanide into the porous network of Vycor® porous glass tubes, was applied to derive the precursor Carbon/Vycor® composites. All precursors underwent a second cycle of IL infiltration/pyrolysis with the target to finetune the pore structural characteristics of the carbonaceous matter nesting inside the separation layer. The pore structural assets and evolution of the gas permeation properties and separation efficiency of the as-derived composite membranes were investigated with reference to the duration of the second infiltration step. The transport mechanisms of the permeating gases were elucidated and correlated to the structural characteristics of the supported carbon phase and the analysis of LN2 adsorption isotherms. Regarding the gas separation efficiency of the fabricated Carbon/Vycor® composite membranes, He/CO2 ideal selectivity values as high as 4.31 at 1 bar and 25 °C and 4.64 at 0.3 bar and 90 °C were achieved. In addition, the CO2/N2 ideal selectivity becomes slightly improved for longer second-impregnation times.

A novel Schiff base sensor through “off-on-off” fluorescence behavior for sequentially monitoring Al3+ and Cu2+

A novel Schiff base probe N'-(2-hydroxybenzylidene)-5-(naphthalen-1-yl)oxazole-4-carbohydrazide (G1) was designed and prepared based on a condensation of 5-(naphthalen-1-yl)oxazole-4-carbohydrazide with salicylaldehyde. G1 gave out a bright blue luminescence in the introduction of Al3+ with an ideal selectivity and sensitivity, which could be acted as a fluorescence “turn-on” probe toward Al3+. The resulted complex G1-Al3+ could be applied to be a quenching probe for Cu2+. The complex stoichiometry of G1 with Al3+ and Cu2+ was confirmed to be 1: 2, via Job's Plot, mass spectrometry titration and theoretical calculation. Moreover, G1 had been successfully applied for monitoring target metal ions in real water sample.

A polyimide/poly(N-vinylimidazole) membrane for CO2/CH4 separation with high selectivity and permeability

Membranes with both good permeation and selectivity are highly desired for gas separations. In this study, we synthesized a new 6FDA-type polyimide copolymer 6FDA-BDTA-ODA, and then an organic polymer of poly ( N-vinylimidazole) was doped into the polyimide to prepare mixed matrix membranes (MMMs). We also studied the effect of poly ( N-vinylimidazole) contents on the separation performance of MMMs. The results showed that the ideal selectivity for CO2/CH4 was improved by adding the poly ( N-vinylimidazole) filler. The ideal selectivity reached 63.5 with 6 wt% poly ( N-vinylimidazole) loading with the permeability of 29.2 Barrer. The highly permeable MMMs showed a considerably enhanced performance for CO2/CH4 that close to the 2008 Robeson upper-bound. The gas separation performance of the prepared MMMs for CO2/CH4 was improved compared to that of the pure polymer membrane, indicating that the copolyimide/poly ( N-vinylimidazole) MMMs have promising applications in CO2/CH4 gas separation.

In-situ synthesis of CNT/UiO-66-NH2-based molecularly imprinted nanocomposite membranes for selective recognition and separation of sulfamethoxazole: A synergistic promotion system

Sulfamethoxazole (SMX) is a widespread organic contaminant that threatens the ecological environment and human health. Therefore, it is of great significance to develop an effective method for selective separation of SMX from the aquatic environments. Herein, a novel in-situ synthesis of CNT/UiO-66-NH2 based molecularly imprinted nanocomposite membranes (CUMIMs) is designed for selective removal of SMX. The CNT/UiO-66-NH2 nanocomposite is prepared through in-situ growth of MOFs in the presence of CNT. The CNT around the MOFs can effectively avoid the aggregation of CNT/UiO-66-NH2 nanocomposite and introduce unique properties into the PVDF/PVA membrane, which simultaneously benefit in both hydrophilicity and water flux. More importantly, the well dispersed CNT/UiO-66-NH2 nanocomposite with huge specific in the membrane can facilitate the selectivity toward SMX. The selective separation performance of CUMIMs is evaluated by static adsorption and permeselectivity experiments. The results showed that the synthesized CUMIMs afford an ideal rebinding selectivity (αSMX/SMM = 2.01, αSMX/TC = 4.34, and αSMX/CIP = 4.65) and permselectivity factor (β = 2.15) toward SMX. The presented strategy on CUMIMs fabrication would potentially enrich the application of CNT/MOFs-based molecularly imprinted nanocomposite membrane in the field of contaminant separation.

Rich Ether-Based Protic Ionic Liquids with Low Viscosity for Selective Absorption of SO2 through Multisite Interaction

Four low-viscosity protic ionic liquids (PILs) with the tertiary amine and rich ether skeletons are designed for selective absorption of SO2. To evaluate the selective absorption of SO2 by these PILs, the solubilities of SO2, CO2, and H2S are measured in the temperature range of 303.2–333.2 K and pressures up to 120 kPa by a volumetric method, respectively. The absorption of SO2 by [TMEA][MOAc] at 303.2 K and 101.3 kPa was found to be 10.424 mol·kg–1 (4.310 mol·mol–1), and the ideal selectivity of SO2/CO2 was 86.83. In addition, the solubility data are fitted using a reaction equilibrium thermodynamic model to obtain thermodynamics parameters including Gibbs free energy change (ΔrGm), enthalpy change (ΔrHm, ΔphyHm, ΔchemHm), and entropy change (ΔrSm). The mechanism of SO2 absorption by [TMEA][MOAc] is also investigated by FTIR and NMR analyses. Mechanistic and thermodynamic studies suggest that the high SO2 absorption is attributed to the O–SO2 multisite physical interaction. These ether-rich PILs are considered as a promising absorber because of their high SO2 solubility, good cycling performance, and low viscosity before and after absorption.

In Situ Tracking of Nonthermal Plasma Etching of ZIF-8 Films.

Surface characterization is critical for understanding the processes used for preparing catalysts, sorbents, and membranes. Nonthermal plasma (NTP) is a process that achieves high reactivity at low temperatures and is used to tailor the surface properties of materials. In this work, we combine the capabilities of infrared reflection absorption spectroscopy (IRRAS) with NTP for the in situ interrogation of zeolitic imidazolate framework-8 (ZIF-8) thin films to probe modifications in the material induced by oxygen and nitrogen plasmas. The IRRAS measurements in oxygen plasma reveal etching of organic ligands with sequential removal of the methyl group and imidazole ring and with the formation of carbonyl moieties (C═O). In contrast, nitrogen plasma induces mild etching and grafting of nitrile groups (-C≡N). Scanning electron microscopy imaging shows that oxygen plasma, at prolonged times, significantly degrades the ZIF-8 film at the grain boundaries. Treatment of ZIF-8 membranes using mild plasma conditions yields a fivefold enhancement for H2/N2 and CO2/CH4 ideal selectivities and an eightfold enhancement for CO2/N2 ideal selectivity. Additionally, the new tools described here can be used for spectroscopic in situ tracking of plasma-induced chemistry on thin films in general.

Facilitated propylene transport in mixed matrix membranes containing ZIF‐8@Agmim core‐shell hybrid material

AbstractThe ZIF‐8@Agmim core‐shell hybrid material was synthesized via a favorable post‐modification method of ion exchange (PMIE). This infrequent ZIF‐8@Agmim core‐shell structure maintains a well‐integrated pore size that is almost the same as ZIF‐8. The similar equilibrium isotherms with ZIF‐8 and better kinetic separation toward propylene/propane than ZIF‐8 render ZIF‐8@Agmim to be an interesting candidate for propylene/propane separation. The core‐shell hybrid nanomaterial was further used as nanofillers in the polymer of intrinsic microporosity matrix (PIM‐1) for propylene/propane separation. The resultant mixed‐matrix membranes (MMMs) exhibited a simultaneous increase in C3H6 permeability and C3H6/C3H8 ideal selectivity compared to pure polymer membrane owing to a synergistic effect of molecular sieving from ZIF‐8 and π‐complexation of Ag+ with propylene. The separation performance of the prepared MMM surpasses the upper bound line of polymer membranes. Furthermore, the hybrid materials possess superb photochemical stability and the corresponding MMMs exhibit excellent anti‐aging property and long‐term stability.

ZIF-67 membranes supported on porous ZnO hollow fibers for hydrogen separation from gas mixtures

Co-based zeolitic imidazolate framework-67 (ZIF) membranes present impressive potential to be applied for efficient gas separation. However, the synthesis of ZIF-67 membrane is challenging because ZIF-67 crystals tend to nucleate and grow in the reaction solution rather than on the substrate surface. In this work, ZIF-67 membranes were developed on porous ZnO hollow fibers via in situ solvothermal growth method. The effects of different ZnO supports, surface activation, growth duration, and growing temperatures on the resultant membrane performance were carefully investigated. The optimized ZIF-67 composite hollow fiber membrane displayed desirable permeation performance, ideal selectivities for single gas, and separation factors for gas mixtures. The achieved H2 permeance was 8.98 × 10−8 mol m−2 s−1·Pa−1and ideal selectivities for H2 gas pairs with CO2, N2, and CH4 were 5.14, 11.75, and 15.89, respectively, which compared favorably with other reports in the literature. The developed ZIF-67 membrane exhibited good stability in terms of gas permeances between 30 and 200 °C. Furthermore, the membrane showed almost constant H2 permeance and H2/CH4 separation factor during the 50-h run at 150 °C, demonstrating the excellent thermal stability of membrane. The fabrication of the excellent ZIF-67 membrane can be achieved just in one cycle of growth with high reproducibility.

A novel organic solvent nanofiltration (OSN) membrane fabricated by Poly(m-phenylene isophthalamide) (PMIA) under large-scale and continuous process

The organic solvent nanofiltration (OSN) membranes are an attractive candidate that enable carbon-neutral nature in both isolation and purification process. However, the application of current commercial available OSN membranes is severely hindered by their inferior permeability and selectivity. Here, using poly(m-phenylene isophthalamide) (PMIA) as support, a thin film composite (TFC) membrane with remarkably high permeability and ideal selectivity is fabricated in an industrial-scale manufacturing line and the relevant spiral-would module is successfully prepared. Optimization by the solvent activated, the TFC membrane with an extraordinary solvent permeation for acetone, methanol and acetonitrile are 63, 41 and 38 L m −2 h −1 ∙bar −1 , respectively. The nanofiltration performance of A-TFC membrane supports out-performs: at similar rejection (100%) the methanol and acetonitrile permeance increased dramatically at 10 and 5 times than current commercial OSN membranes, respectively. The spiral-would module is carried out in methanol and acetonitrile RB (1017 g mol −1 ) solution, which displays a high permeate fluxes and stable separation performances, methanol: 112 GPD, 98%; acetonitrile: 99 GPD, 99.3%. This work provided a large-scale facile process for high-performance PMIA based OSN membrane, and the fabrication of spiral-would module, which should be promising for manufacture of solvent-resistant TFC membrane in industrial scale-up. • A TFC OSN membrane was firstly fabricated by PMIA at a large-scalable and continuous process. • Prepared A-TFC membranes were found to have an extraordinary solvent permeation for acetone, methanol and acetonitrile. • Prepared A-TFC membranes presented the excellent permeability and high dye rejection. • The spiral-would module with stable permeate fluxes and good separation performances.

ZIF-8/GO sandwich composite membranes through a precursor conversion strategy for H2/CO2 separation

It is difficult to control the heterogeneous nucleation and growth of crystals on porous supports, the preparation of thin ZIF-8 membranes is still extremely challenging. Herein, a two-dimensional transformation strategy is demonstrated for constructing a ZIF-8/GO ‘sandwich’ composite membrane with a thickness of ∼0.9 μm, which was prepared from Zn-EG-AC (EG: ethylene glycol, AC: CH3COO-groups, abbreviated as ZnEG) on alumina hollow fiber support for the first time by precursor conversion method in 2-methylimidazole methanol solution. The effects of the amount of precursor, reaction time and membrane thickness on the membrane structure and H2/CO2 separation performance are explored. The sieving effect of ZIF-8 and the adsorption effect of 2-methylimidazole rings on CO2, as well as the strong interaction between GO and CO2 hinder the permeation of CO2 into the membrane, thus exhibiting a good H2/CO2 ideal separation selectivity of 30.8 with the H2 permeance of 1.36 × 10−7 mol·Pa−1·m−2·s−1 under the optimized preparation conditions. The separation factor of the equimolar H2/CO2 binary-mixture gases stabilizes to ∼25 after 30 h. This precursor conversion strategy is expected to be extended to other MOF/graphene oxide (GO) composite membrane systems.

Novel bio-polymer based membranes for CO2/CH4 separation

This work deals with the utilization of the poly(lactic acid) (PLA) to fabricate biopolymer membranes by phase inversion technique for the treatment of gaseous streams rich in CO2 and CH4. PLA is an excellent biopolymer constituting a viable option to most of the traditional fossil-based polymers, possessing zero environmental impact once exhausted and interesting gas separation properties as membranes. Several parameters of the phase inversion process were studied in order to identify the optimal PLA membrane preparation, as a function of the best performance in terms of ideal CO2/CH4 selectivity, CO2 permeability and membrane degradability. The PLA membranes were fully characterized in terms of morphology, thickness, differential scanning calorimetry, Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy analyses. Afterwards, single gas permeation tests were performed in order to prove the relevance of PLA membranes in CO2/CH4 separation, and membrane degradation tests under water as well. The results of the wide experimental campaign on PLA membranes preparation evidenced how specific membrane samples (thickness > 25 μm) possess quite high CO2/CH4 ideal selectivity (between 220 and 230) and CO2 permeability ∼ 11 Barrer at ambient temperature, which allowed to collocate this biopolymer based membrane material above the correspondent Robeson's upper bound.

Selective separation of HFC-32 from R-410A using poly(dimethylsiloxane) and a copolymer of perfluoro(butenyl vinyl ether) and perfluoro(2,2-dimethyl-1,3-dioxole)

Currently, millions of kilograms of HFCs and HFC mixtures are in use with no method for efficiently separating the components. Membranes are an attractive method for separating HFC refrigerant mixtures due to both lower energy consumption and capital requirements compared with alternative separation methods such as distillation. This study investigates the use of poly(dimethylsiloxane) and CyclAFlor™, an amorphous copolymer of 5 mol% perfluoro(butenyl vinyl ether) and 95 mol% perfluoro(2,2-dimethyl-1,3-dioxole), for the separation of R-410A, an azeotropic mixture composed of 50 wt% difluoromethane (HFC-32, CH2F2) and 50 wt% pentafluoroethane (HFC-125, CHF2CF3). Pure gas permeability of HFC-32 and HFC-125 were measured using a static membrane apparatus and the pressure-rise method. Solubility and diffusivity were measured using a gravimetric microbalance. Permeability measurements indicate high selectivity of HFC-32 over HFC-125 with CyclAFlor™, and mixed gas selectivity measurements utilizing a mixed gas apparatus are in excellent agreement with ideal selectivity calculations based on solubility and diffusivity measurements. Stability studies indicate that plasticization of the fluorinated amorphous polymer membrane is minimal in the presence of HFC-32 and HFC-125.