Development and Characterization of Mesoporous Silicate–LiCl Composite Desiccants for Solid Desiccant Cooling Systems

Abstract

Solid composite desiccants are fabricated by impregnating LiCl into pores of SBA-15 and MCM-41 mesoporous silicates. In the study, characteristics including textural properties and equilibrium and dynamic water sorption were tested and analyzed. Research on nitrogen adsorption suggested that because of the impregnated salt, composite desiccants were different from pure silicates. Sorption isotherms were measured and simulated based on Polanyi potential theory. Composite samples had water uptake much higher than that of pure hosts under low and middle relative pressure owing to mutual contribution of both physical and chemical sorption. Sorption kinetics were also tested and fitted with a linear driving force model. The composite desiccant prepared from SBA-15 exhibited higher dynamic sorption quantity and a reasonable diffusion rate constant. Finally, dehumidification performance of the composite desiccant in a novel solid desiccant cooling component was evaluated with a mathematical model. Simulation results indicated that enhanced dehumidification capacity can be achieved using the composite desiccant.