Ammonia sorption on the composites "(BaCl sub(2) + BaBr sub(2)) inside vermiculite pores"

This paper presents the data on the phase composition and ammonia sorption equilibrium of the new composite sorbents "(BaCl sub(2) + BaBr sub(2)) inside vermiculite pores" intently prepared for adsorptive cooling. Phase transformation of the composites during ammonia sorption was characterized by in situ X-ray diffraction. The isotherms of ammonia sorption on the composites were measured in the ammonia pressure range P = 0-10 bar at temperatures T = 303-343 K. The formation of the salts solid solution BaCl sub(x)Br sub(2-x) inside the vermiculite pores was observed. Due to the ammonia sorption this solution transformed to the complex BaCl sub(x)Br sub(2-x).8NH sub(3), which formation was observed at intermediate ammonia pressure between those for the single salts BaCl sub(2) and BaBr sub(2). The isosteric enthalpy Delta H of ammonia sorption on the composites with molar ratio BaCl sub(2)/BaBr sub(2) 3:2 and 1:1.2 equals (-35 plus or minus 3) kJ/mol and does not depend on the ammonia uptake. The isosteric entropy Delta S changes from (-115 plus or minus 2) to (-133 plus or minus 2) J/(mol K) with the increase in the ammonia sorption from 1 to 7 mol NH sub(3)/mol salt.