Nanoporous materials with enhanced hydrophilicity and high water sorption capacity

The main types of nanoporous adsorbents for water arc identified and described with emphasis on the mechanism of adsorption, modification, improvement of the water sorption capacity, possible regeneration, and stabilization. Among the three main groups of water sorbents, i.e. inorganic materials (zeolitecs, clays, silica), carbon based materials and organic polymers, the first one is described in details. The significance of their porosity, chemical and structural features relative to the water adsorptive properties of each inorganic type materials is reviewed. Important features for silicates, zeolites, aluminophosphates, mesoporous materials and clays are described, which define the interactions between the water and the porous structures. The significant improvements of the water sorption capacity of nanoporous materials under modification of their surface, particle size, morphology, and chemical specificity arc explored for each type of inorganic porous compounds. The hydrophilic nanoporous materials are of significant importance for construction of regularly operating sorption equipments, reversible physi- or chemisorption reactors for generation of heat and cold, purification of lubricants, and sensing of water with different concentrations. (c) 2007 Elsevier Inc. All rights reserved.