Study of interactions between relevant organic acids and aluminium in model solutions using HPLC and IC

Abstract

The interactions of different organic acids such as citric, malic, oxalic, and fulvic with aluminium were studied using ion-exchange chromatography (IC) and high performance liquid chromatography (HPLC). The experiments were carried out at low pH (1.5-3.1). The results of IC experiments on the interaction between Al and oxalate, citrate, and malate were compared with model chemical equilibrium calculations. The strongest effect on Al speciation was observed with oxalic acid and fulvic acid. These two ligands formed more than one type of complex with Al. In contrast, there was no significant effect of malic acid on Al speciation and a rather weak effect caused by citric acid. The studies show that the formed complexes are stable even at low pH.