Modeling of Water Adsorption Isotherms on Clinoptilolite

An isotherm of water vapor adsorption on clinoptilolite was constructed within the framework of the thermodynamic approach in the range of relative air humidities from 0 to 1 at physically acceptable parameters of the system. The isotherm has a characteristic inflection point in the region of average humidity; due to this, it can be classified as an isotherm of the fourth type, which has a hysteresis loop at certain values of the system parameters. It is concluded that the resulting model isotherm describes adsorption in mesoporous materials, such as ion exchangers used in agrochemical practice, and is fully consistent with the experimental adsorption isotherm of this type.