Preparation and characteristics analysis of the new-type silica gel/CaCl2 adsorbents with nanoparticles for adsorption desalination and cooling system

The adsorption desalination and cooling system (ADCS), a promising technology for alleviating water scarcity, requires adsorbents with high performance, low cost, and low energy consumption. Enhancing the operating efficiency and minimizing the energy consumption of the system entails improving the adsorption performance and thermal conductivity of adsorbents. In this study, nanoparticles (NP) embedded silica gel (SG) composite adsorbents with CaCl2 were synthesized for use in ADCS. The effects of nano-Fe, nano-Cu and carbon nanotubes (CNT) as SG thermal conductivity enhancers were thoroughly compared through microscopic properties, thermal properties and adsorption properties. The experimental results show that SG/CNT/CaCl2 composite performs the largest specific surface area and pore volume of 180.72 m(2) g(-1) and 0.13 cm(3) g(-1). Scanning electron microscopy (SEM), accelerated surface area and porosimetry (ASAP) and constant thermal analyzer (TCA) were used to characterize the various performance of the enhanced adsorbents comprehensively. SG/CNT/CaCl2 sample exhibits high thermal conductivity and thermal diffusion coefficient, measuring as high as 0.664 W m(-1) K-1 and 0.701 x 10(-6) m(2) s(-1), respectively. Based on dynamic water adsorption performance tests, the SG/CNT/CaCl2 composite had an adsorption capacity of 0.665 g g(-1), five times higher than SG. The composite's adsorption capacity and thermal conductivity did not decline significantly during cycling, indicating a high degree of sustainability. Therefore, these results imply that the nanoparticles-embedded SG/CaCl2 adsorbent with excellent integrated properties has promising prospects in adsorption desalination systems.[Graphical]

Automated summary

This study compared the effects of different thermal conductivity enhancers on the performance of silica gel/calcium chloride composite adsorbents and found that carbon nanotubes (CNTs) are the most effective enhancers. Experimental results show that the CNT-embedded gel composite has a larger specific surface area and pore volume, high thermal conductivity and thermal diffusion coefficient, as well as higher adsorption capacity and thermal stability. Therefore, this composite adsorbent has promising prospects in adsorption desalination systems for addressing water scarcity.