Inclusion chromatography using cyclodextrin-containing resins and studies of nonlinear chromatographic theories
Abstract
Cylcodextrins are a family of cyclic-oligosaccharides, containing usually six to eight glucopyranose units. Because of their unique donut-shaped steric structure they are able to form inclusion complexes selectively with some guest molecules. In this work, a novel method of synthesizing cyclodextrin-containing resins for inclusion chromatography has been developed. Resins synthesized with this method possess a very high content of cyclodextrins and good physical properties. Experiments on the adsorption isotherms and stepwise adsorption/desorption column operations have been carried out to separate some biomolecules. Efforts have been made to recover phenylalanine from industrial waste samples using a $\beta$-Cyclodextrin column. Some water soluble aliphatic alcohols have been found to be good displacers. A robust and efficient numerical procedure has been developed to solve a general multicomponent rate model which considers axial dispersion, external film mass transfer, intraparticle diffusion and nonlinear isotherms. The method uses finite element and orthogonal collocation methods to discretize the bulk phase and particle phase partial differential governing equations, respectively. The resulting ordinary differential equation system is then solved by Gear's stiff method. The model has also been extended to include second order kinetics, size exclusion, and the reaction between soluble ligands and macromolecules in the fluid phase for the study of affinity chromatography. Computer simulations of stepwise displacement qualitatively proved some of the experimental observations. A methodology has been developed to derive kinetic and isotherm models, which have successfully demonstrated isotherm cross-over and peak reversal phenomena for multicomponent systems with uneven saturation capacities. A unified approach based on a displacement effect has been proposed to explain the dominating interference effect in multicomponent chromatography. System peak patterns in binary elution have been summarized. Various aspects, including operational stages, the rate-limiting step and two types of inhibition in affinity chromatography have been analyzed. Multicomponent rate models for radial flow chromatography (RFC) have also been solved using an accurate numerical treatment in which the radial dispersion and the external film mass transfer coefficients are treated as variables. A comparison of, and mathematical analogy between, RFC and conventional axial flow chromatography have been made.
Degree
Ph.D.
Advisors
Tsao, Purdue University.
Subject Area
Chemical engineering
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