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

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 kg_H2O/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.