Browsing by Autor "Natalia Castrillo"

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Reversibility Studies of Clay Hydration Degree in its Natural and Composite Condition
(Elsevier BV, 2015) Natalia Castrillo; Adela Mercado; Cristina Bolzone
In this work, the regeneration of desiccant compounds materials was studied after of its adsorption capacity. Also, reuse of the materials was evaluated after progressive regenerations. For this, the effect of regeneration temperature on adsorption capacity of the desiccant compounds materials was analyzed. For the tests adsorption of water a certain amount of dry sample was placed in a desiccator at 98% RH and 298 K, until reach the time of equilibrium, in which the final weight was recorded. In order to check the reversibility of the process re-adsorption studies were performed with water. To do this, before starting the second adsorption cycle, the same portion of sample was dried again to release the adsorbed water (drying temperatures: 343 K and 373 K). Later was proceeded similarly to first adsorption cycle. After to this procedure was reiterated 5 times the test results showed no significant decrease in the efficiency of the material when the samples were regenerated at 373 K. In this way, was possible to maintain approximately constant the hygroscopic characteristics of the material. From the results it was determined that the optimum temperature of drying for the regeneration process is to the corresponding to 373 K since at this temperature the rate of desorption of water is facilitated, which allows to adapt the material in order to initiate an new cycle, being in evidence a good behavior of the material in reversibility
Sorption Water by Modified Bentonite
(Elsevier BV, 2015) Natalia Castrillo; Adela Mercado; C. Volzone
In order to improve adsorptive properties and provide a viable alternative to humidity control techniques, the desiccants can be modified with chemical aggregates such as calcium chloride (CaCl2), the latter often used as dehydrating due to its hygroscopicity and low cost. Its use as a drying agent has disadvantages because of its particles form a liquid film. However, the CaCl2 may be mixed with other materials for preparing desiccant products. In this work we studied, at 298 K and different relative humidities (RH), the adsorption processes of desiccants mixtures composed of a bentonite clay Argentinian and CaCl2. The results showed a better performance of the desiccant mixture with respect to natural clay in the whole HR working range. It was also observed that addition of CaCl2 favors adsorptive properties with respect to a purification treatment.