Experimental investigation of sodium polyacrylate-based innovative adsorbent material for higher desalination and cooling effects

This study explores enhancing adsorption system's performance utilizing sodium polyacrylate (SP) as an adsorbent for the first time. Four innovated SP samples are explored: raw SP, SP/HCl, SP/(NH₄)₂CO₃), and SP/CaCl₂ composite for adsorption desalination and cooling applications. Different characterization methods, including X-ray diffraction, nitrogen adsorption isotherm, and water adsorption (isotherms and kinetics) of SP samples, are investigated. Water adsorption experimental results onto SP samples and their numerical fitting with the Dubinin-Astakhov equilibrium model for isotherms and linear driving force model for kinetics have been expressed. The composite SP/CaCl₂ had the highest experimental adsorption uptake of 1.26 kgH₂O/kg among the studied samples. At 85 °C regeneration temperature, water desalination production per day (SDWP) achieves 15 m³/ton, with a cooling power of 425 W/kg. SDWP could reach 41 m³/ton of SP/CaCl₂ per day with heat recovery. The system can obtain an SDWP of 45 m³/ton per day at a regeneration temperature of 95 °C. The findings show that the system can run efficiently using renewable energy, waste heat, or geothermal energy as heat sources.