Gas permeation parameters of mixed matrix membranes based on the polymer of intrinsic microporosity PIM-1 and the zeolitic imidazolate framework ZIF-8

• Published in: Journal of membrane science Vol. 427; no. 15; pp. 48 - 62
• Main Authors: Bushell, Alexandra F., Attfield, Martin P., Mason, Christopher R., Budd, Peter M., Yampolskii, Yuri, Starannikova, Ludmila, Rebrov, Alexander, Bazzarelli, Fabio, Bernardo, Paola, Carolus Jansen, Johannes, Lanč, Marek, Friess, Karel, Shantarovich, Victor, Gustov, Vadim, Isaeva, Vera
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2013; Elsevier
• Subjects: artificial membranes; carbon dioxide; Diffusion coefficients; diffusivity; ethanol; Free volume; Gas permeability; gases; hydrogen; methane; Mixed matrix membranes; nanoparticles; nitrogen; oxygen; permeability; Permeability–permselectivity diagrams; polymers; radio; sorption; Sorption isotherms; spectroscopy; thermoluminescence; Free volume; Gas permeability; Permeability–permselectivity diagrams; Diffusion coefficients; Mixed matrix membranes; Sorption isotherms
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2012.09.035

Mixed matrix membranes (MMMs) based on the polymer of intrinsic microporosity PIM-1 and the zeolitic imidazolate framework ZIF-8 were prepared and their permeation and sorption properties investigated. Self-supported films with ZIF-8 contents up to 43vol% were studied using GC gas permeation apparatus and a McBain sorption microbalance. Permeability coefficients were determined for the following set of gases: He, H2, O2, N2, CO2, CH4. For “as-cast” films, an increase in ZIF-8 loading results in increases in the permeability and diffusion coefficients as well as in the separation factors α(H2/N2), α(H2/CH4), α(He/N2), α(O2/N2) and α(CO2/CH4). For all ZIF-8 contents studied, permeability is enhanced by treatment with ethanol. Data points on several Robeson diagrams are located above the 2008 upper bound. Free volume in MMMs containing ZIF-8 was studied using positron annihilation lifetime spectroscopy (PALS) and radio thermoluminescence (RTL) methods. It was shown that the introduction of ZIF-8 nanoparticles into the PIM-1 matrix results in an increase in free volume which may be assumed to arise from a combination of the contributions cavities and of more loosely packed polymer chains at the boundary between ZIF-8 particles and the PIM-1 matrix. The results obtained for the PIM-1/ZIF-8 MMMs are compared with literature data for other MMMs. ► Preparation of a new type of mixed matrix membranes (MMM) based on PIM-1 and ZIF-8. ► Increase in permeability and separation factors of MMM with increase in the content of ZIF-8. ► Sorption isotherms of CO2 in MMM with varying content of ZIF-8. ► Increase in free volume due to the introduction of ZIF-8 into PIM-1 matrix. ► Robeson diagrams: the data points of various PIM-1/ZIF-8 compositions are above the upper bounds for different gas pairs.