Study of the influence of pH and of the interactions involved in etheramine removal in kaolinite: insights about adsorption mechanism

Abstract

As the adsorption process involves interactions between molecules of the adsorbate and the surface of the adsorbent material, theoretical studies are developed with the aim of elucidating the mechanism. In this work, the influence of pH on adsorption of etheramine in kaolinite was investigated. The results showed that adsorption was most efficient at pH 10, which was attributed to the equilibrium of the etheramine molecules between ionic and molecular forms creating an ionic–molecular complex that promotes adsorption. Theoretical calculations confirmed these results and showed that the ionic–molecular dimer is the most stable structure among the possible dimers (ionic-ionic, molecular-molecular, and ionic-molecular).