Studies in Solvent Sublation: Extraction of Methyl Orange and Rhodamine B

Abstract

The technique of solvent sublation has been investigated for the solutes methyl orange and rhodamine B together with the cationic surfactant, hexadecyltrimethylammonium bromide. In solvent sublation, gas bubbles generated in an aqueous phase are used to selectively extract material into a nonaqueous phase, which is immiscible with the water. Presumably attachment to the bubbles occurs through adsorption at the gas-liquid interfaces by surface-active species. The effects of parameters such as gas flow rate and concentration of surfactant on the rates of extraction of the two dyes have been investigated. Marked differences in the behavior of the dyes have been found, suggesting different mechanisms of extraction. A direct comparison has also been made between solvent sublation and solvent extraction, the latter using vigorous shaking to provide intimate contact between the liquid-liquid interfaces. Finally, the potential of solvent sublation in the separation field has been discussed.