Reaction Kinetics of LiOH·H_2O and CO_2 Improved with Composite Silica Gel of Lanthanum Chloride

摘要

Reaction kinetics of LiOH·H2O and CO2 within a closed system were studied under the adsorption of water vapor by composite silica gel of lanthanum chloride. At the reaction temperature of 273～323 K and initial CO2 pressures of 40～100 kPa, reaction kinetics obeyed the Erofeev model. The reaction rate decreased slightly while the initial CO2 pressure reduced. When the reaction occurred at 273～299 K, the reaction rate was so low that it was almost independent of the reaction temperature. However, as the temperature rose up to 300～323 K, LiOH·H2O dehydrated its crystal water, and both the dehydrated and reaction-generated water were evaporated from solid reactant. For the dehydration rate increased, the reaction rate also increased as the reaction temperature rose. While the temperature was higher than 323 K, the reaction apparent activation energy of LiOH·H2O and CO2, was higher than 52.5 kJ·mol-1 and close to 61.4 kJ·mol-1 of the LiOH·H2O dehydrated enthalpy variable at 298 K, in which anhydrous LiOH was the major reactant and showed the reaction characteristics of LiOH crystals.