Carbon dioxide facilitated transport membranes

Amide-containing dibenzo-16-crown-5 compounds, transport of metal perchlorates, 161-165 Amine(s) as carriers, carbon dioxide facilitated transport through functional membranes prepared by plasma graft polymerization, 252-268 Amine solutions, carbon dioxide facilitated transport through supported liquid membranes, 239-250 Amino acid derivatives, use as heavy metal ion carriers, 175-179... 

From the late 1960s to the early 1980s, Ward and others at General Electric studied facilitated transport membranes, particularly for separation of the acid gases carbon dioxide and hydrogen sulfide from methane and hydrogen [23-26],... 

Concurrently with the work on carbon dioxide and hydrogen sulfide at General Electric, Steigelmann and Hughes [27] and others at Standard Oil were developing facilitated transport membranes for olefin separations. The principal target was the separation of ethylene/ethane and propylene/propane mixtures. Both separations are performed on a massive scale by distillation, but the relative volatilities of the olefins and paraffins are so small that large columns with up to 200 trays are required. In the facilitated transport process, concentrated aqueous silver salt solutions, held in microporous cellulose acetate flat sheets or hollow fibers, were used as the carrier. 

Quinn R, Appleby JB, and Pez GP. New facilitated transport membranes for the separation of carbon dioxide from hydrogen and methane. 7 Mem 5d, 1995 104(1-2) 139-146. 

Klmura et al. (J 2) reported progress toward applying facilitated transport membranes to industrial scale separations. They measured carbon dioxide and hydrogen sulfide permeabilities at industrially significant operating conditions (6.90 x io kPa COj, 363 03 K). Under these conditions, the authors determined that carbon dioxide transport is influenced by both diffusion and reaction rates. 

Trachtenberg MC, Tu CK, Landers RA, Willson RC, McGregor ML, Laipis PJ, Kennedy JF et al. Carbon dioxide transport by proteic and facilitated transport membranes. Life Support Biosph Sci 1999 6(4) 293-302. 

Facilitated Transport of Carbon Dioxide Through Functional Membranes Prepared by Plasma Graft Pofymerization Using Amines as Carrier... 

J. Huang, Carbon dioxide capture using a C02-selective facilitated transport membrane, Ind. Eng. Chem. Res., 2008, 47, 1261-1267. 

This chapter reviews the recent developments of two types of facilitated transport membranes (1) supported liquid membranes (SLMs) with strip dispersion and (2) carbon-dioxide-selective polymeric membranes, for environmental, energy, and biochemical applications. 

Some of the available membrane separation processes can already be applied on an industrial scale. Hence, inorganic ceramic membranes (zeolites and their derivatives, e.g. silico aluminophosphates), organic polymer membranes and facilitated transport membranes, which rely on a carrier molecule with high CO2 affinity to achieve selective CO2 transport (such as metallic ions or liquid amines), have been used in separating CO2 from flue gas in post-combustion. As single-stage separation with these membranes is still difficult, new membrane materials are being developed [1]. Typically, the initial separation of carbon dioxide accounfs for 60-80% of the total cost of CO2 sequestration [24,25]. 

Transport. A wellknown transport protein is hemoglobin in the erythrocytes (bottom left). It is responsible for the transport of oxygen and carbon dioxide between the lungs and tissues (see p.282). The blood plasma also contains many other proteins with transport functions. Prealbumin (transthyretin middle), for example, transports the thyroid hormones thyroxin and triiodothyronine. Ion channels and other integral membrane proteins (see p.220) facilitate the transport of ions and metabolites across biological membranes. 

FIGURE 13.14 Schematic diagrams of facilitated transport of gas using capillary membrane module for removal and enrichment of carbon dioxide, (a) Experimental capillary membrane apparatus and (b) capillary membrane modules with permeation of carrier solution. (From Teramoto, M., Ohnishi, N., Takeuchi, N., et al., Sep. Purif TechnoL, 30, 215, 2003. With permission.)... 

One of the first applications of TSOSs was reported in 2002. Davis and his team have shown that an amine-derived imidazolium salt can capture carbon dioxide by forming a ammonium carbamate [28], Primary amine functionalized imidazolium salts have also been used for facilitating C02 transport through a supported liquid membrane showing high selectivity and high stability for CH4/C02 separation [50] (Fig. 18). 

Carbon dioxide, a neutral species, passes through the red-blood-cell membrane into the cell. This transport is also facilitated by membrane transporters including proteins associated with Rh blood types. Carbon dioxide stimulates oxygen release by two mechanisms. First, the presence of high concentrations of carbon dioxide leads to a drop in pH within the red blood cell (Figure 7.20). 

The aromatic polyimides, cited earlier, separate carbon dioxide over methane with a-valves of 150-160. Aromatic polyoxadiazoles have a-valves of 100-2 00.157 The permeability of one aromatic polyimide was improved by two to four orders of magnitude by carbonizing it on porous alumina,158 the final a-valve being 100. In this case, the final actual membrane was probably a porous carbon molecular sieve. Facilitated transport has also been used to increase the separation factor. A porous poly(vinylidene difluoride) membrane with ethanolamine or diethanolamine in the pores gave a separation factor of carbon dioxide over methane of 2000.159 Such a method is less energy-intensive than when an amine is used in the usual solvent method. 

---