Gas chromatographic measurement of gas-solid interaction potentials and solid surface areas

Abstract

Gas adsorption retention chromatographic volumes at high temperature are closely related to adsorption and are therefore sources of information concerning gas-solid interaction potentials and surface areas. Dependence of ietention volumes on temperature over the temperature range 300-700°K has been established for argon, nitrogen, carbon monoxide, methane, ethylene, ethane, propylene and propane on Columbia activated carbon. A simple method based on an asymptotic form is presented for evaluation of gas-solid interaction potential parameters. Over the temperature ranges investigated, data are adequately represented in each case by a 3 : 9 gas-solid interaction potential, but this representation is not unique. Interaction parameters TO = -E ( x o ) / ~ and Ax0 ( A is the surface area, xo the distance from surface to potential energy minimum, and E(XO) is the gas-solid interaction energy at the potential energy minimum) are evaluated by both asymptotic and exact methods, results by the two methods being in excellent agreement. The estimation of the parameter xo is discussed. Surface areas based on measured values of Ax0 and estimated values of xo are less than the B.E.T. nitrogen surface area of the adsorbent by factors varying from 2.5 for argon to 6.7 for propylene.

Predicting second gas–solid virial coefficients using calculated molecular properties on various carbon surfaces

“…(4) integral can be evaluated by numerical integration provided A, T , E * , and z * are known. An approximate equation derived by Hansen [36][37][38] shows that Eqs. (2) and (4) can be approximated by a simple equation [31],…”

Adsorption energies for a nanoporous carbon from gas–solid chromatography and molecular mechanics

“…The exponential attractive term is expected to be m = 3 for the dispersion forces of a gas attracted to a solid whereas different values ranging from 9 to 18 have been used for the exponential repulsive term, n [28]. An equation derived by Hansen [33][34][35] shows that Eqs. (5) and (6) together can be approximated by [36] (7)…”

Molar Refractivity and Connectivity Index Correlations for Henry's Law Virial Coefficients of Odorous Sulfur Compounds on Carbon and for Gas-Chromatographic Retention Indices

“…[4] integral can be evaluated by numerical integration. However, a simpler, although approximate, alternative is provided by an equation derived by Hansen and co-workers (31)(32)(33). Hansen has shown that Eq.…”