Effect of porous additives on properties of the attapulgite-based cacl ₂ composites for cooling applications

The effects on the properties of composites when adding porous materials (13X zeolite, silica gel, or alumina) were investigated based on the preparation and performance testing of attapulgite-based CaCl₂ composites. The adsorption performance of the composites was carried out using the static weighing method, and the desorption behavior was done through thermal analysis. Also, the composite adsorbents were characterized by x-ray diffraction. The results show that low 13X zeolite and alumina additives could yield a positive water adsorption effect and improve the dispersion of CaCl₂ in composite adsorbents, thus increasing their water adsorption properties at low relative humidity. The desorption temperature of the composite adsorbents was not affected by the addition of lower than 25% of porous materials. The adsorption stability of the composites was improved for suppression of CaCl ₂ agglomeration due to the dispersion promoting effect of porous materials. At a relative humidity of 20%, water uptakes on the composite with 20% 13X zeolite content could reach 0.36kg/kg, which is 20% higher than the original attapulgite-based CaCl₂ composite.