Kinetics of the sorption of water vapors on type a zeolites Communication 2. Dependence of the diffusion coefficient on the degree of filling

Conclusions

• 1. The kinetics of the sorption of water vapors were investigated on two samples of type A zeolite at temperatures of 20, 50, 100 and 150°.

• 2. he diffusion coefficients decrease with decreasing value of the adsorption, while at a temperature of 150° in the region of low degrees of filling, they again increase, exhibiting a maximum in the region of degrees of fillingθ > 0.2.

• 3. The activation energy of the diffusion process in the region of degrees of filling 0 < 0.4 decreases with increasing adsorption; in the region 0=0.4–0.8 it remains approximately constant and equal to 3600–4000 cal/mole, while in the region 0 > 0.8 it again increases. An analogous pattern is observed in the dependence of the entropy of activation on the degree of filling.

• 4. The results of the experiments with entirely dehydrated zeolites show that the rate of adsorption is determined by the concentration gradient in the adsorption phase. These results confirm the scheme of the diffusion of water vapors in granulated zeolites adopted earlier, according to which the deciding factor is diffusion in the crystals.