The equilibrium and kinetic characteristics of vanillin (4-hydroxy-3-methoxybenzaldehyde) uptake by a highly basic type II macroporous anion exchanger have been studied. It is shown that the isotherm of vanillin sorption by the Trilite AMP-26 anion exchanger is well described by the Langmuir equation over the entire range of concentrations under study, which made it possible to evaluate the thermodynamic characteristics of the process taking into account the calculated sorption constants. The obtained kinetic curves of uptake of 4-hydroxy-3-methoxybenzaldehyde by the sorbent under static conditions at different stirring rates allowed us to determine the time required to reach equilibrium in the system and showed that this time does not depend on the stirring rate of solutions. The limiting stage of sorption was assessed using a formal kinetic approach based on the Boyd–Adamson equations and taking into account the influence of experimental factors on the rate of vanillin uptake by the anion exchanger. The structural changes in the sorbent phase after contact with a 4-hydroxy-3-methoxybenzaldehyde solution were determined by IR spectroscopy.
Rybkina et al. (Wed,) studied this question.