Water vapor adsorption/desorption on granulated binder-free low-module zeolites

Ivanovo State University of Chemistry and Technology, Department of Technology of Inorganic Substances, Ivanovo, Russia

Abstract

A characteristic of granulated LTA and SOD zeolites is given. It was determined that LTA zeolite particles have a cube shape with a size of ~2 μm; SOD particles have an irregular shape with a size of 0.5–1 μm. The dimension of the coherent scattering region was calculated to be 760 nm for LTA and 453 nm for SOD. The specific surface area of LTA is 115 m2·g–1 and SOD is 141 m2·g–1. Static tests of granulated zeolite showed that the maximum quantity of absorbed water vapor for LTA was ~30 wt.%, and for SOD ~20 wt.%. It was found LTA zeolite to provide adsorption of water from the gas to a dew point of –50 °C, and SOD zeolite of –9 °C. The apparent activation energies for the desorption of water on zeolites were calculated using isoconversional analysis of Friedman, Ozawa–Flynn–Wall, and Kissinger–Akahira–Sunose.