Adsorption of aromatic amino acids in a fixed bed column

Abstract

Phenylalanine (Phe) and tyrosine (Tyr) are two of the twenty amino acids in proteins; they are classified as aromatic amino acids, because both have a benzene ring in their structures. These amino acids are important in the synthesis of several biologically active amines, such as beta-endorphin, a neurotransmitter. Amino acids can be separated by ion-exchange chromatography. In this case, it is important that fixed-bed adsorber design adequately predict the breakthrough curve. This work presents a mathematical model for both fluid and porous phases. In the solution proposed for this model the liquid-phase concentration inside the particles is solved analytically and is related to the liquid-phase concentration in the bed using Duhamel's theorem. The solution for liquid-phase concentration in the bed is then solved numerically instead of analytically. The basic mass transfer parameters are from the literature. The results from the model are compared with those obtained experimentally using Phe and Tyr diluted in aqueous solutions in a fixed bed of PVP (poly-4-vinylpyridine) resin

Hybrid method of solution applied to simulation of pulse chromatography

“…In order to obtain this mathematical model, some assumptions are fixed: the flow rate is constant; the transversal cross section is constant for and through the column; radial dispersion is negligible; the axial dispersion coefficient is a function of solute and flow rate; the external mass transfer resistance is considered; the solids are made of spherical particles with uniform radius; the solution is dilute and thus adsorption isotherm is linear; and the pore diffusion model describes the intra-particle transport mechanism. These assumptions were applied to the description of the breakthrough curve (Cremasco et al, 2003), the model of which is summarized in Table 1. In the condition (8), C in is the solute concentration in the flow entering the column.…”

“…The intra-particle liquid solute concentration is found analytically and correlated to the liquid bed concentration through Duhamel's theorem. The use of this theorem results in an equation connecting the intraparticle liquid concentration, C p , to the liquid bed concentration, C. This method is described in Cremasco et al (2003).…”

“…In this paper, the method proposed by Cremasco et al (2003) is applied to predict single and low concentration pulse chromatography. A general rate (GR) model is presented, and a hybrid method is used.…”

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Abstract -In this communication, the method proposed by Cremasco et al (2003) is applied to predict single and low concentration pulse chromatography. In previous work, a general rate model was presented to describe the breakthrough curve, where a hybrid solution was proposed for the linear adsorption.

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Modeling for Taxol® Separation in a simulated moving bed

“…An adsorption process evolution was computationally determined for a system containing compound mixture, using a hybrid method. Based on Cremasco et al (2003), the liquid concentration inside the particles was found analytically and it was related with the liquid bed concentration using Duhamel's theorem. The solution for the liquid bed concentration was found numerically, instead of analytically.…”