Heats of Adsorption of Argon

Abstract

The calorimetric heats of adsorption have been measured for argon at -195°on a series of carbon blacks graphitized at the successively higher temperatures, 1000, 1500, 2000 and 2700 °. X-Ray and electron microscope studies reported by Schaeffer, et al., indicate a higher degree of graphitization with increasing temperature of heat treatment; this w-ould result in progressively more homogeneous surfaces within the series. Our experimental results illustrate clearly the change in the shape of the heat-coverage curve with increasing degree of surface homogeneity produced by high temperature heat treatment. These results may be correlated with the stepwise isotherms found by Polley, et al., on the same series of blacks.

Effects of surface mediation on the adsorption isotherm and heat of adsorption of argon on graphitized thermal carbon black

“…Experimental isosteric heats of argon on GTCB at 77 K are available in the literature, for example, Beebe et al [20,21], Grillet et al [18]. Bobka et al [22], Pace and Siebert [23], and Avgul and Kiselev [19].…”

On the anatomy of the adsorption heat versus loading as a function of temperature and adsorbate for a graphitic surface

“…In adsorption from the gaseous phase, information about the heat can be a very valuable supplement to isotherm measurements. Experimentally isosteric heat can be measured either by calorimetric means [1][2][3][4][5][6][7][8][9], or calculated using the Clapeyron equation from isotherms at various temperatures. This only provides us with the overall heat released from the process.…”

The Structure of Artificial Graphites as Revealed by X-Ray, Electron Microscope, and Adsorption Studies

“…In every case, the isotherms were smooth Type I1 isotherms without any of the humps which have become associated with homogeneous surfaces (1). Hence, it was concluded that these graphites presented heterogeneous surfaces to gases a t liquid nitrogen temperatures.…”