Characterization and cost analysis of a modified silica gel-based adsorption desalination application

Abstract

This study aims to reduce adsorption desalinated water cost by innovative employing silica gel/CaCl2 composite and novel silica gel/(NH4)2CO3 activated materials. Raw silica gel (SG), which served as the host matrix, was acid-treated and impregnated with CaCl2 and (NH4)2CO3. The prepared samples characteristics (XRD, N2 adsorption, water vapor adsorption) have been investigated and compared to the raw SG. A simulation model has been used to investigate the impact of the study samples on adsorption desalination (AD) system performance with and without heat recovery (HR). The study also includes a cost analysis of the AD water production system (using the tested materials) that uses solar energy or a waste heat source. The SG/CaCl2 achieved the highest water adsorption (0.95 kgH2O/kg) with a SDWP of 23.3 m3/ton per day, SCP 660 W/kg, and COP 0.71. With HR, the system could produce 35 m3/ton of SG/CaCl2 per day SDWP. The study concluded that the tested samples outperform the raw material as the total production cost of AD water using SG/CaCl2 has been reduced to approximately 37% using solar energy and 60% using waste heat as a regenerative heat source.