Methane sorption

Figure 1. Methane sorption isotherms measured at T = 77.35 K on four different AlP04-5 zeolite samples S(l), S(2), S(3) and S(4).

Fig. 1. CO2 and methane sorption isotherms for the Lower Cretaceous Mannville Group high volatile bituminous B coal, Alberta. 

In an MD study of methane sorption and diffusion in silicalite, Nicholas et al. (67) identified favorable sites for sorption. From the MD calculations, the time-averaged position of the center of mass of the methane molecule was plotted. Energy minimization calculations were then performed, locating the methane molecule at positions where the MD calculations predicted they spent the most time. Each channel intersection region was found to contain two sites that are minima for methane-zeolite interactions. These two sites are separated by a translation parallel to the straight channel... 

The permselectivity of hydrocarbon vapors, p, is dominated by the sorption component, and sorption of hydrocarbon vapors by rubbery polymers is determined by the condensability of their vapors. It can be seen from Table 9.3, that in organosilicon polymers the propane/methane sorption selectivity, is 10.5-16.2, whereas diffusion selectivity, is only 0.16-0.41. Refs. [39 3] report values of permselectivity of hydrocarbon mixtures with nitrogen for organosilicon membranes produced by GKSS (see Figure 9.10). It can be seen that separation selectivity increases with rising boiling temperature of the hydrocarbon, which points to domination of the sorption component of selectivity. 

The initial isosteric heats of sorption of these hydrocarbons in silicalite-1 are listed in Table 1 which includes the corresponding heats of sorption in NaY for comparison and, also, the heats of sorption of CH4 for completeness but these methane sorption studies will be described, more fiilly, later. 

Isosteric heats of adsorption for methane sorption in carbon-based compounds fall within the exact storage range close to ambient temperatures, which makes organic porous compounds important candidates for methane storage. 

Figure 9. Sorption isobars calculated from coal-methane sorption isotherms measured between temperatures 120-294 K [15]. o P/Patm=0.7 V 0.3 0.05.

Fig. 39.5 (a) Small voids enclosed within columns of 3. (b) Methane sorption isotherm of a 2 and b 3 at high pressure (Reproduced with permission from Ref. [22]. Copyright 2005, Royal Society of Chemistry)... 

Figures (a) Squashed cuboctahedral cages and (b) absolute high-pressure methane sorption isotherms at various temperatures (Reprinted with permission from Ref. 32. Copyright (2008) American Chemical Society.)...

Figure 6 (a) The pore structure of UTSA-20 along the c axis and (b) excess high-pressure methane sorption isotherms of UTSA-20 at various temperatures (Reproduced with permission from Ref 34. Wiley-VCH Verlag GmbH Co. KGaA, 2011.)... 

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