Silver polymer electrolyte membranes for facilitated olefint transport: carrier properties, transport mechanism and separation performance

Abstract

Facilitated transport membranes for the separation of olefin/paraffin mixtures have long been of interest in separation membrane science because olefins, such as propylene and ethylene, which are important chemicals in petrochemical industries, are currently separated by energy-intensive cryogenic distillation processes. Recently, solid polymer electrolyte membranes containing silver ions have demonstrated remarkable performance in the separation of olefin/paraffin mixtures in the solid state and, thus, they can be considered as alternatives to cryogenic distillation. Here, we review recent progress, and critical issues affecting in the use of facilitated olefin transport membranes; in particular, we provide a general overview with reference to carrier properties, transport mechanisms, and separation performance.

The structural transitions of π-complexes of poly(styrene-b-butadiene-b-styrene) block copolymers with silver salts and their relation to facilitated olefin transport

“…Such silver polymer electrolyte membranes show high separation performance for olefin/paraffin mixtures [13][14][15][16][17][18][19][20][21][22][23][24][25]. In particular, when silver salts with low lattice energy such as AgBF 4 such as poly(ethylene oxide) (PEO), poly(2-ethyl-2-oxazoline) (POZ), and poly(N-vinyl pyrrolidone) (PVP) to form silver polymer electrolytes, silver ions can be utilized as olefin carriers in facilitated transport.…”

Gas separation membranes containing Re6Se8(MeCN)6 2+ cluster-supported cobalt-porphyrin complexes

“…In contrast, P carrier-mediated is dependent on the concentration of oxygen reversibly-bound to a fixed carrier, upstream pressure, and the reversible oxygen-binding equilibrium constant of the carriers within the membrane. 12,13 The N 2 permeability of membrane-containing oxygen carriers, on the other hand, depends only on the properties of the membrane matrix. Since the chain flexibility and the free volume of the membrane matrix are expected to change upon addition of an oxygen carrier, it can be assumed that the N 2 permeability corresponds to the permeability of the matrix.…”

Propylene-induced plasticization in silver polymer electrolyte membranes

“…The ideal separation factor of propylene/propane based on pure gas permeation is as high as 15,000 and the propylene permeance reaches 45 GPU (1 GPU = 1 Â 10 À6 cm 3 (STP)/ cm 2 s cmHg) [11,14]. However, the mixed gas selectivity is approximately 40-60 [16,17]. The difference in the selectivity between the pure gas and the mixed gas seems to be primarily due to the swelling-induced plasticization of the membranes and also the interaction between the gases in the mixed gas [20][21][22].…”

“…Over the last several years, solid-state facilitated transport membranes using silver polymer electrolytes have been extensively investigated to separate olefin/paraffin mixtures such as propylene/propane or ethylene/ethane [10][11][12][13][14][15][16][17][18][19]. The basis for the separation is reversible, specific interaction between propylene molecules and silver ions dissolved in polymeric matrix, resulting in facilitated propylene transport through the membranes.…”