Interactions of aromatic acids with montmorillonite: Ca2+- and Fe3+-saturated clays versus Fe3+-Ca2+-clay system

Benny Chefetz, Shay Eldad, Tamara Polubesova*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Aromatic acids are involved in important soil processes, such as mobilization of microelements by plants and formation of humic components. Interactions of aromatic acids (benzoic, vanillic, p-coumaric, syringic and ferulic) with Ca2+- and Fe3+-saturated montmorillonite were studied, and the role of aqueous Ca2+ in aromatic acid adsorption to Fe3+-montmorillonite was investigated. Removal of aromatic acids at pH 3 and changes in partial molar free energy of adsorption of benzoic acid were higher for Fe3+-montmorillonite than for Ca2+-montmorillonite. Adsorption of aromatic acids on Ca2+-montmorillonite decreased similarly with increasing pH. The aromatic acids could be divided into two groups according to their behavior on the surface of Fe3+-montmotillonite with increasing pH: i) ferulic and syringic and ii) benzoic, vanillic, and p-coumaric. Adsorption of the studied acids by Fe3+-montmorillonite was affected by their molecular structures. Adsorption of benzoic acid by Fe3+-montmorillonite increased in the presence of 5mM CaCl2. Adsorption of aqueous Ca2+ on Fe3+-montmorillonite was high (0.59mmoc/g), and was not influenced by the concentration of benzoic acid. Desorption of benzoic acid from Fe3+-Ca2+-montmorillonite was greater than that from Fe3+-montmorillonite. For the former system, adsorption hysteresis of benzoic acid increased with increasing acid concentration. The current study demonstrates a role of aqueous Ca2+: when adsorbed from the soil solution to iron-containing surfaces, it can change their adsorptive properties towards low-molecular-weight acids.

Original languageAmerican English
Pages (from-to)608-613
Number of pages6
JournalGeoderma
Volume160
Issue number3-4
DOIs
StatePublished - 15 Jan 2011

Keywords

  • Adsorption
  • Benzoic acid
  • Clay
  • Exchangeable cation
  • Hysteresis

Fingerprint

Dive into the research topics of 'Interactions of aromatic acids with montmorillonite: Ca2+- and Fe3+-saturated clays versus Fe3+-Ca2+-clay system'. Together they form a unique fingerprint.

Cite this