Imidazolium-based ionic liquid confined into ordered mesoporous MCM-41 for efficient dehumidification

Composite sorbents with hygroscopic salts (like LiCl and CaCl 2 ) impregnated porous matrixes obtained special attention in the past years, especially for solid desiccant dehumidification. However, the drawback of strong corrosivity limited their practical implementation. Alternatively, ionic liquid (1-ethyl-3-methylimidazole acetate) with less corrosivity is confined into ordered mesoporous MCM-41 to fabricate composite sorbent in this study, overcoming the poor mass transfer or limited adsorption capacity of single sorbent. Comprehensive characterizations including SEM, TEM, XRD, FTIR and N 2 adsorption prove that the ionic liquid is encapsulated in ordered channels of MCM-41. Sorption isotherms and kinetics indicate that the composite sorbent has superior water sorption performance (0.5 g/g at 20 °C/70 % RH), fast sorption rate under wide humidity range and potential of low temperature-driven regeneration. Moreover, the leakage test and corrosion experiment reveal that the composite sorbent has long-term stability and is corrosion-free to metal components. Further, the dehumidification performance using desiccant coated heat exchanger with reported composite sorbent is evaluated, showing 5 times higher dehumidification capacity than that of MCM-41 and 2 times higher than traditional silica gel (typical ARI summer, 35 °C, 40 % RH). This study identifies a feasible way of using ionic liquids to develop energy-efficient, safety-ensured and low-cost composite sorbents for water sorption-related applications.