Adsorption of carbon monoxide‐nitrogen, carbon monoxide‐oxygen, and oxygen‐nitrogen mixtures on synthetic zeolites

Abstract

Experimental results for the adsorption of the binary gas mixtures oxygen-nitrogen, oxygencarbon monoxide and nitrogen-carbon monoxide on two synthetic zeolites are reported. In a l l of these experiments the temperature was -200°F. and the total pressure was 1 atm. Also reported are the isotherms for the three pure gases on the two zeolites a t -200°F. The results indicate that these zeolites have a surface selectivity which is independent of any sieving effect based on the size of the adsorbed molecules. It does not appear that the strong separations obtained can be explained in terms of the van der Waals forces which are generally believed to be dominant in physical adsorption. The available methods of predicting binary adsorption data from the pure gas isotherms have been examined, Data on the adsorption equilibria of gas mixtures are important both from a practical viewpoint for the design of gas adsorbers and on a theoretical basis for the understanding of the interactions between gases and solid surfaces. Compared to the voluminous data in the literature on pure gas adsorption, very little data are available on the adsorption of gas mixtures. For a complete understanding of the behavior of gas molecules in the sphere of influence of a solid, the forces of molecular interactions must be quantitatively treated. Such a statistical mechani- R. P. Danner is at the

A Thermodynamic Model for Gas Adsorption Isotherms

“…Constants a, b, and c in Eq. [16] can be easily determined from the experimental data. Equation [16] can be converted into a linear form in terms of z as where Y ϭ (1 Ϫ z) Ϫ2 ln(P/z).…”

“…[16] can be easily determined from the experimental data. Equation [16] can be converted into a linear form in terms of z as where Y ϭ (1 Ϫ z) Ϫ2 ln(P/z). By simple linear regression of Y versus z, parameters a, b, and c for each isotherm can be determined.…”

“…Although Eq. [16] is implicit in z, it can be solved by Newton's method to find z when P is known. For systems in which Eq.…”

The vacancy solution model of adsorption—improvements and recommendations

“…The above correlation scheme was tested with data for 02, Nz, and CO adsorbed on zeolite 1OX at 144.3, 172.0,227.6, and 273.2 K (Danner and Wenzel, 1969;Dorfman and Danner, 1975;Nolan et al, 1981) and with the data for CzH4, CzH6, i-C4H10. and COz adsorbed on zeolite 13X at 273.2, 298.2, 323.2, and 373.2 K (Danner and Choi, 1978;Hyun and Danner, 1982).…”

“…Binary parameters were regressed from the experimental data for the binary mixtures of 0 2 , NZ, and GO adsorbed on zeolite 1OX at 144.3, 172.0, 227.3, and 273.2 K (Danner and Wenzel, 1969;Dorfman and Danner, 1975;Nolan et a]., 1981), for C2H6-i-C4H10, CzH4-CO2, a n d CzH6-CzH4 mixtures adsorbed on zeolite 13X at 298.2 and 323.2 K (Danner and Choi, 1978;Hyun and Danner, 1982), and for i-C4H10-C2H4 mixtures adsorbed on zeolite 13X at 298.2, 323.2, and 373.2 K (Hyun and Danner, 1982). Attempts were made to regress isothermal values for both A12 and A21 directly.…”