Water Vapor Adsorption Characteristics of Aerogels for Desalination

Adsorption-Desalination (AD) system has been suggested and has proven to be a low-energy desalination method employing a low-temperature heat-driven adsorption/desorption cycle for desalination. Only commercialized silica gel is used to produce fresh water by desalinating seawater vapor in this process, but the pores’ limitations restrict the amount of water uptake and harsh operating conditions. The development of novel porous adsorbents able to achieve high water vapor uptake at low temperature and relative pressure is a high priority to be incorporated into the AD system. Aerogels are has emerged as a promising candidate as an adsorbent because of their high pore and thermal characteristics. In this study, hydrophilic or hydrophobic aerogels were prepared by sol-gel method using different silica sources. Raman spectroscopy was applied to investigate structural changes of aerogels during water vapor adsorption. Enhancement of adsorption/desorption rate of aerogels were examined by dynamic vapor adsorption analyzer. Our results offer the potential in application of AD system utilizing aerogels with high water vapor uptake.