DIMER PHYSISORPTION ON HETEROGENEOUS SUBSTRATES

Physisorption of dimers on heterogeneous surfaces is studied by combin ing theoretical modelling, Monte Carlo simulation and experimental res ults. Monte Carlo simulation of dimer physisorption is carried out for substrates modelled in such a way that random, patchwise and intermed iate adsorption site topographies can be generated. Simulated adsorpti on isotherms are used to test a model for adsorption of polyatomic mol ecules on heterogeneous surfaces, recently developed by Nitta et al.. Experimental adsorption isotherms for O-2 and N-2 adsorbed on zeolites 5A and 10X, as well as adsorption heats, are used to test the reliabi lity of the simulation model. A simple theoretical form for the adsorp tion isotherm, based on the Fermi-Dirac approach, is finally proposed, Close agreement between simulated, theoretical and experimental resul ts supports the validity of the proposed equation to describe interact ions of diatomic gases with zeolites.