Experiments on Sorption Properties of gamma-Manganese Dioxide under Isothermal Conditions

摘要

To characterize promising solid desiccant materials for solar desiccant cooling applications, we measured the sorption properties of gamma-manganese dioxide under isothermal conditions using gravimetric methods. Tests were performed at 20 sup 0 C and 40 sup 0 C, a flow rate of about 110 cm sup 3 /min, a pressure of 1 atm, and relative humidities between 3% and 90%. We found the equilibrium water capacity of gamma-manganese dioxide to be much lower than that of silica gel (5% compared with 37% to 40%). The uncertainty in the manganese dioxide capacity calculation is relatively high (+-14%) because of the low sorption capacity of the small sample available (less than 0.3 g). Because of its low adsorption capacity, it cannot be used as a stand-alone desiccant in desiccant dehumidifiers. It may be used in composites with silica gel if its moisture diffusivity is considerably higher than that of silica gel. The moisture diffusivity in manganese dioxide and silica gel/manganese dioxide composites needs to be assessed and compared with that of silica gel for evaluating the composites as advanced desiccants. (ERA citation 11:004075)