Search results for "Supercritical adsorption"
showing 3 items of 3 documents
Fixed Bed Adsorption of Drugs on Silica Aerogel from Supercritical Carbon Dioxide Solutions
2013
Supercritical adsorption coupled with the high adsorption capacity of silica aerogel allows the preparation of a new kind of delivery systems of poor water soluble drugs. In order to overcome drawbacks of conventional techniques where the use of liquid solvents can cause the fracture of aerogel porous structure, in this work a new adsorption process of drugs from a supercritical mixture is proposed. Adsorption takes place from a fluid solution of the drug in supercritical CO2and ethanol as cosolvent. A fixed bed adsorption plant has been developed to allow fast mixing of fluid phase and effective contact in the adsorption column. The use of ethanol as cosolvent allows to overcome the limita…
Silica aerogel–metal composites produced by supercritical adsorption
2010
Abstract Silica aerogel has been loaded with ruthenium acetyl acetonate (Ru(acac) 3 ) by adsorption from supercritical carbon dioxide. Adsorption isotherms and kinetics were measured at different pressures and temperatures. The properties of impregnated aerogel were obtained by optical and electron microscopy (SEM), X-ray microanalysis (EDX) and thermogravimetric analysis (TGA). Results showed that Ru(acac) 3 can be uniformly dispersed into the aerogel up to 5 wt%. Moreover, precursor loading is controllable by properly changing operating conditions. The adsorbed metallorganic compound has been reduced to elemental ruthenium by heat treatment without inducing degradation and morphological c…
Eumelanin Coating of Silica Aerogel by Supercritical Carbon Dioxide Deposition of a 5,6-Dihydroxyindole Thin Film
2018
Eumelanin integration in silica aerogel (SA) was achieved via supercritical adsorption of 5,6-dyhydroxyindole (DHI) from CO2. Notably, after the supercritical treatment, DHI evolved towards spontaneous polymerization, which resulted in uniform pigment development over the SA. The new material was characterized for its morphological and physicochemical properties, disclosing the formation of a eumelanin-like coating, as confirmed by UV&ndash