The application of anion-exchange resins containing functional primary amino-groups for the extraction of vanillin from aqueous solutions under dynamic conditions

Abstract

The possibilities of functional polymeric sorbents containing primary amino groups application for
vanillin (4-hydroxy-3-methoxybenzaldehyde) extraction from aqueous solutions in dynamic conditions are
studied. As objects of study weak-basic anion-exchange resins Purolite A 830 and Granion D 309 have been
selected. Based on the analysis of vanillin breakthrough curves on anion-exchange resins it is found that the
sorption ability of the functional polymers is affected by the amount of reactive amino groups, as well as by
their spatial accessibility.
The important criterion when choosing an effective sorbent for the target task is the presence of a
macroporous matrix, which significantly reduces the steric hindrance in the sorption of aromatic aldehydes.
Evaluation of anion-exchange resins surface morphology confirms the fact that the anion-exchange
resin D 309 has smaller pores in comparison with A 830, which do not allow it to implement sorption
capacity to such substance as vanillin. To establish the possibility of the sorbent regeneration the desorption
of aldehyde has been performed using 0.5 M HCl and NaOH. It is revealed that the use of these regeneration
solutions allows one to extract vanillin by 60 and 50%, respectively. The mechanism of desorpion in strongly
acidic or strongly basic media is hydrolysis of the imines formed during the interaction of vanillin with
primary amino groups on the sorbents.
Thus, the dynamics of vanillin sorption and desorption by weak-basic anion-exchange resins is
studied. It is shown that these sorbents can be used to extract vanillin from technological solutions.