Kinetics of Adsorption for Cyclopentane in Silicalite -1

The adsorption and adsorption kinetics of cyclopentane in silicalite - 1 has been studied by using intelligent gravimetric analyze technology. From experiments, curves were obtained which give the amount of the adsorbed sorbate as a function of the square root of time. Such curves were measured for various pressure jumps and, correspondingly, different coverages as well as for different temperatures. The result shows that the diffusion of cyclopentane in silicalite- 1 can well be derived from the second Fick law, and the diffusivity D increases with temperature. A tendency, meanwhile, could be noticed that the diffusivity decreases with increasing coverage under the constant temperature. In addition to the particular pore system of silicalite- 1 zeolite with the straight channel, the sinusoidal channel and the intersection between them affecting the diffusion of sorbate, the feature of sorbate cyclopentane also influences the process, such as the molecular dimension. Moreover, the change of activation energy, activation entropies and the heat of sorption for cyclopentane with various sorption coverages determined the change of diffusion coefficients for cyclopentane. The isotherms shows that the bigger activation energy, the smaller activation entropies and the sorption heats determined the diffusion coefficients for cyclopentane are a little bit more than that for benzene. The interactions between the cyclopentane molecules increase with increasing sorption coverage. The data and relevant graph in this study show believable values and detailed explanations.