Equilibrium and Kinetic Characteristics of Tryptophan Sorption onto FIBAN A-1 Fiber.

In the present study, the possibility of using a strong-base fibrous material FIBAN A-1 (Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus, Belarus) as a sorbent to remove tryptophan from aqueous solutions is investigated. The capacity characteristics of the anion exchangers in the form of granules and fibers containing quaternary ammonium bases as functional groups with respect to the chosen amino acid are analyzed. The influence of the pH of the medium on the sorption of amino indolylpropanoic acid onto the A-1 fiber is determined. IR spectroscopy confirms the fact of the fixation of amino acids from solutions with pH ~5.0–5.5 due to the charge exchange of the zwitterion by the OH groups of the sorbent. The specific features of both the equilibrium and kinetics of tryptophan sorption from solutions with a pH close to the isoelectric point are studied. Based on the analysis of the isotherms of sorption of the amino acid at different temperatures, a monomolecular mechanism of the sorptive sorption process and its endothermic character are established. The kinetic characteristics of tryptophan sorption indicate a significant contribution of external diffusion to the velocity of the investigated process. [ABSTRACT FROM AUTHOR]