Nanoporous carbon membrane, separation

Rao, M.B. and S. Sircar, Nanoporous carbon membranes for separation of gas mixtures by selective surface flow, /. Membr. Sci., 85(3), 253-264, 1993a. 

The nanoporous carbon membrane consists of a thin layer (<10pm) of a nanoporous (3-7 A) carbon film supported on a meso-macroporous solid such as alumina or a carbonized polymeric structure. They are produced by judicious pyrolysis of polymeric films. Two types of membranes can be produced. A molecular sieve carbon (MSC) membrane contains pores (3-5 A diameters), which permits the smaller molecules of a gas mixture to enter the pores at the high-pressure side. These molecules adsorb on the pore walls and then they diffuse to the low-pressure side of the membrane where they desorb to the gas phase. Thus, separation is primarily based on differences in the size of the feed gas molecules. Table 7 gives a few examples of separation performance of MSC membranes. ° Component 1 is the smaller component of the feed gas mixture. 

Sircar, S. Rao, M.B. Nanoporous carbon membranes for gas separation. In Recent Advances on Gas Separation by Microporous Membranes Kanellopoulos, N., Ed. Elsevier Amsterdam, The Netherlands, 2000 473 96. 

Figure 22.7 Descriptions of nanoporous carbon membranes (a) mechanism of transport through the molecular sieve carbon (MSC) membrane, (b) mechanism of transport through the selective surface flow (SSF) membrane, (c) separation performance of H2S—H2 mixtures by the SSF membrane, (d) schematic drawing of a two-stage SSF membrane operation for Fl2S—FI2/CH4 separation.

Table 7.6 Gas separation properties of nanoporous carbon membrane.

S. Sircar and M. B. Rao, "Nanoporous carbon membranes for gas sepmation," in Recent advances on gas separation microporous ceramic membranes," N. Kanellopoulos (ed.), Elsevier, New York, p. 473 (2000). 

In a simulation system, we investigate the equilibrium selective adsorption and nonequilibrium transport and separation of gas mixture in the nanoporous carbon membrane are modeled as slits from the layer structure of graphite. A schematic representation of the system used in our simulations is shown in Fig. 11.21(a) and (b), in which the origin of the coordinates is at the center of simulation box and transport takes place along the x-direction in the nonequilibrium simulations. In the equilibrium simulations, the box as shown in Fig. 11.21(a) is employed, whose size is set as 85.20 nm x 4.92 nm x (1.675 + JV) nm in x-, y-, and z-directions, respectively, where JV is the pore width, i.e. the separation distance between the centers of carbon atoms on the two layers forming a slit pore (Fig. 11.21). is the separation distance between two centers of adjacent carbon atom L is the pore length JV is the pore width, A... 

Rao, M. B. Sircar, S. (1996). Performance and Pore Charaeterization of Nanoporous Carbon Membranes for Gas Separation. Journal of Membrane Science, 110(1), 109-118. Merkel, T. C., etal. (2QQy). Effect of Nanoparticle son Gas Sorption and Transport in Poly (l-trimethylsllyl-l-propyne). Macromolecules, 36(18), 6844-6855. 

Rao MB, Sircar S (1996) Performance and pore characterization of nanoporous carbon membrane for gas separation. J Membr Sci 110(1) 109-118... 

Acharya M, Foley HC (1999) Spray-coating of nanoporous carbon membranes for air separation. J Membr Sci 161 (1-2) 1-5... 

Acharya M (1999) Engineering design and theoretical analysis of nanoporous carbon membranes for gas separation. PhD Thesis, University of Delaware, Newark, DE, USA... 

Shah TN, Foley HC, Zydney AL (2007) Development and eharaeterization of nanoporous carbon membranes for protein ultrafiltration. J Membr Sci 295 (1-2) 40-49 Kim YY, Park HB, Lee YM (2004) Carbon molecular sieve membranes derived from thermally labile polymer containing blend polymers and their gas separation properties. J Membr Sci 243 (1-2) 9-14... 

Recently, Wu et al. used a similar NEMD method to simulate the permeation and separation of H /CO in nanoporous carbon membrane [12]. The schematic diagram of the simulation cell adopted by Wu et al. is given in Fig. 8.19. The difference between Wu et al. [12] and Furukawa and Nitta [11] is that there are buffer zones between the H and M and M and L zones. The schematic representation of the slit pore is as shown in Fig. 8.20. It corresponds to Furukawa and Nitta s SP membrane. 

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