Computer Programs for Calculating Pore Volume and Area Distributions from Gas Adsorption-Desorption and Mercury Intrusion Data Computer programs were written in Fortran IV for calculating the distribution of pore volume and area. as a function of pore radiufi using gas adsorptian-desorption and mercury instrusian data. The program which computes the distributions from the desorption branch of the nitrogen isotherms is designed to be used with a commercially available adsorption apparatus (Orr Surface Area Pore Volume Analyzer, Model 2100, Micrameritics Instrument Corp., Norcross, Ga.). The pore size is obtained by the conventional Kelvin Procedure making allowance for the thickness of the physically adsorbed layer by the use of a continuous function. The vahms for the volume and area of pores a t corresponding intervsls of pore sizes are computed for each deerement of relative pressure and are cumulatively summed. The pare volume a t each interval is also expressed as a. function of total pore volume. In order to provide ~dditianalflexibility with this program, separate programs were prepared to trsnsform the experimental data, into an actual adsorption-desorption isotherm; and to derive the distributions utilizing the adsorption branch with the assumption that desarption occurs along the adsorption isotherm. The program which computes the pore volume and area, distributions from mercury intrusion data is also designed to be used with a commercial instrument (Aminco Porosimeter, Cat. No. 5-7121, American Instrument Co., Silver Spring, Md.). The observed volume of mercury intrusion into the pore system of the solid sample is corrected for t,he apparent compressibility of mercury and the compression of air entrapped in the penetrometer (sample holder) during the introduction of the liquid into the penetrometer. Pore volumes are expressed as functions of pore size and the total pore volume present in the sample. The pore areas are evaluated by numerically integrating the intrusion volume-pressure curves. Completely documented listings of these programs with sample outputs are available on request (write to GEP). HASANGUCLUYILDIZ E. PECK GARNET GILBERTS. BANKER SCHOOL OF PHARMACY AND PHARM~CAL SCIENCES INDIANA 47907 PURDUE UNIVERSITY, WESTLAFAYETTE,
440 / Journol o f Chemicol Education
