Membranes for gas separation

In the system N2/O2, the ABS membrane shows a high selectivity. This property makes this polymeric material attractive as a gas separation membrane for N2 and O2 at moderate temperatures. 

For gas separation membranes, for example, He, O2, and N2 gas transport properties of CA/poly(methyl methacrylate) (PMMA) blends have been measured [108]. This article reported that CA/PMMA blends exhibited phase separation with limited intermiscibility between the components, but they were possibly useful as membrane materials to produce high-purity helium gas streams combined with high helium recovery. 

Powell, C.E. and Qiao, G.G. (2006) Polymeric C02/N2 gas separation membranes for the capture of C02 from power plant flue gases. Journal of Membrane Science, 279, 1-49. 

Ultrafiltration (UF) and microfiltration (MF) membranes can be made on less sophisticated supports. The simplest MF tubular membrane consists of an extruded porous tube (layer 1) as a support coated on the inside or outside with a macroporous layer (layer 2) which serves as the functional filtration layer. The support system shown in Fig. 6.3 is in fact a sophisticated UF or Knudsen gas separation membrane. For less demanding applications a 2-layer support could also be used. 

It was the combination of these stringent requirements which impeded the development of useful gas separating membranes for so many years. Obviously,... 

Czyperek M, Zapp P, Bouwmeester HIM, Modigell M, Ebert K, Voigt I, Meulenberg WA, Singheiser L, and Stover D. Gas separation membranes for zero-emission fossil power plants MEM-BRAIN. J. Membr. Sci. 2010 359 149-159. 

M. Czyperek, P. Zapp, H. J. M. Bouwmeester, M. Modigell, K.-V. Peinemann, 1. Voigt, W. A. Meulenberg, L. Singheiser, D. Stover, MEM-BRAIN gas separation membranes for zero-emission fossil power plants. Energy Procedia, 1, 303-310 (2009). 

In EP07708077A3 (Dabou et al. 1996), gas separation polymer membranes were prepared from mixtures of a polysulfone, Udel P-1700 and an aromatic polyimide, Matrimid 5218. The two polymers were proven to be completely miscible as confirmed by optical microscopy, glass transition temperature values and spectroscopy analysis of the prepared mixtures. This complete miscibility allowed for the preparation of both symmetric and asymmetric blend membranes in any proportion from 1 to 99 wt% of polysulfone and polyimide. The blend membranes showed significant permeability improvements, compared to the pure polyimides, with a minor change in the selectivity. Blend membranes were also considerably more resistant to plasticization compared with pure polyimides. This work showed the use of polysulfone-polyimide polymer blends for the preparation of gas separation membranes for applications in the separation of industrial gases. 

Sanders DF, Smith ZP, Guo R, Robeson LM, McGrath JE, Paid DR, et al. Energy efficient polymeric gas separation membranes for a sustainable future a review. Polymer 2013 54 4729-61. 

Lately, a large proportion of research efforts have been focused on the development of gas separation membranes for CO2 captnre, nnder pre- or postcombustion conditions, becanse membrane technology offers a more environmentally friendly and sustainable approach compared with traditional systems (ie, absorption columns) and can compete in a wide variety of operating conditions with liqnid absorption [25]. 

ILs have negligible vapor pressures, so there is no drying out of the electrolytes, thus reducing hazards associated with flash points and flammability (Baker et al. 2005 Anastas 2007). The low volatility of ILs has been d onstrated in gas-separation membranes for separation of SO and CO (Jiang et al. 2007). The SO selectivity of separations using IL membranes has been shown to be 9-19 times that of CO. ... 

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