ABSTRACT
Admieellar-enhanced chromatography (AEC) is a new fixed-bed separation process based on the use of surfactants to induce the adsorption of a solute from an aqueous stream. In AEC, an adsorbed layer of surfactant is formed reversibly on the surface of a packing material. Solute molecules from a process stream partition into the surfactant layer in a phenomenon called adsolubilization, which is a surface analog of solubilization. When the surfactant layer—or, equivalently, the bed—becomes saturated with the solute, the surfactant layer with the solute is stripped from the packing by a change of pH in the inlet stream to the bed. This can be readily accomplished because of the nature of the surface-charging phenomenon that is used to induce the formation of the surfactant layer in the first place. The concentration of the solute in the stream of material stripped from the bed can be adjusted by controlling the pH of the stripping stream, and may be much higher than the original concentration of the solute in the process stream. AEC has now been used in bench scale applications to concentrate a phenolic compound from an aqueous stream, to separate isomers of an alcohol, and shows promise as an industrial scale method for separating optical isomers.
