Phenolic acids interactions with clay minerals

A spotlight on the adsorption mechanisms of Gallic Acid onto montmorillonite

Adoum Mahamat Ahmat, Thomas Thiebault, Regis Guegan

Research output: Contribution to journalArticle

Abstract

For a better understanding of the preservation of organic matter in clay minerals, the adsorption of a model humic substance, the Gallic Acid (GA), onto a Na-montmorillonite (Na–Mt) was performed in batch situation for various experimental conditions (pH = 2, 5, 7) in order to mimic the natural context. The adsorption efficiency and change in the clay mineral were characterized via a set of complementary experimental techniques (Fourier transform infrared spectroscopy, X-ray diffraction, elemental analyses). Adsorption isotherms at the equilibrium were fitted with the models of Langmuir, Freundlich and Dubinin-Radushkevitch allowing one to precisely quantify the adsorption through the derived fitting parameters. From the adsorption data combined with complementary results of the modeled humic-clay complexes, different types of interactional mechanisms were inferred as a function of background acidity: (i) at pH = 2 while protonated GA was the preponderant form, anionic GA species can be adsorbed to the Na–Mt surface through electrostatic interaction, leading to the a slight covering of the clay surface favoring in a second step the GA adsorption by π-π and Van der Waals forces; XRD patterns corroborated via TGA and FT/IR results suggested the actual intercalation of the phenolic acid within the interlayer space; (ii) At pH = 5, above the pKa of phenolic acid, only 20% of the protonated form subsisted and these species were adsorbed via coordinative bonding, without however any perceptible intercalation; (iii) and in the regime with neutral environment (pH = 7), the preponderance of GA anionic species led to a poor adsorption which appeared to be only located at the external surface of the clay mineral.

Original languageEnglish
Article number105188
JournalApplied Clay Science
Volume180
DOIs
Publication statusPublished - 2019 Nov 1

Fingerprint

Bentonite
Gallic Acid
Clay minerals
montmorillonite
clay mineral
adsorption
Adsorption
acid
Intercalation
Humic Substances
X-ray diffraction
Van der Waals forces
clay
Coulomb interactions
Adsorption isotherms
Acidity
Biological materials
phenolic acid
humic substance
FTIR spectroscopy

Keywords

  • Adsorption
  • Montmorillonite
  • Organic matter preservation
  • Phenolic acids

ASJC Scopus subject areas

  • Geology
  • Geochemistry and Petrology

Cite this

Phenolic acids interactions with clay minerals : A spotlight on the adsorption mechanisms of Gallic Acid onto montmorillonite. / Ahmat, Adoum Mahamat; Thiebault, Thomas; Guegan, Regis.

In: Applied Clay Science, Vol. 180, 105188, 01.11.2019.

Research output: Contribution to journalArticle

@article{c59bd0612d514357bc436e88198f108c,
title = "Phenolic acids interactions with clay minerals: A spotlight on the adsorption mechanisms of Gallic Acid onto montmorillonite",
abstract = "For a better understanding of the preservation of organic matter in clay minerals, the adsorption of a model humic substance, the Gallic Acid (GA), onto a Na-montmorillonite (Na–Mt) was performed in batch situation for various experimental conditions (pH = 2, 5, 7) in order to mimic the natural context. The adsorption efficiency and change in the clay mineral were characterized via a set of complementary experimental techniques (Fourier transform infrared spectroscopy, X-ray diffraction, elemental analyses). Adsorption isotherms at the equilibrium were fitted with the models of Langmuir, Freundlich and Dubinin-Radushkevitch allowing one to precisely quantify the adsorption through the derived fitting parameters. From the adsorption data combined with complementary results of the modeled humic-clay complexes, different types of interactional mechanisms were inferred as a function of background acidity: (i) at pH = 2 while protonated GA was the preponderant form, anionic GA species can be adsorbed to the Na–Mt surface through electrostatic interaction, leading to the a slight covering of the clay surface favoring in a second step the GA adsorption by π-π and Van der Waals forces; XRD patterns corroborated via TGA and FT/IR results suggested the actual intercalation of the phenolic acid within the interlayer space; (ii) At pH = 5, above the pKa of phenolic acid, only 20{\%} of the protonated form subsisted and these species were adsorbed via coordinative bonding, without however any perceptible intercalation; (iii) and in the regime with neutral environment (pH = 7), the preponderance of GA anionic species led to a poor adsorption which appeared to be only located at the external surface of the clay mineral.",
keywords = "Adsorption, Montmorillonite, Organic matter preservation, Phenolic acids",
author = "Ahmat, {Adoum Mahamat} and Thomas Thiebault and Regis Guegan",
year = "2019",
month = "11",
day = "1",
doi = "10.1016/j.clay.2019.105188",
language = "English",
volume = "180",
journal = "Applied Clay Science",
issn = "0169-1317",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - Phenolic acids interactions with clay minerals

T2 - A spotlight on the adsorption mechanisms of Gallic Acid onto montmorillonite

AU - Ahmat, Adoum Mahamat

AU - Thiebault, Thomas

AU - Guegan, Regis

PY - 2019/11/1

Y1 - 2019/11/1

N2 - For a better understanding of the preservation of organic matter in clay minerals, the adsorption of a model humic substance, the Gallic Acid (GA), onto a Na-montmorillonite (Na–Mt) was performed in batch situation for various experimental conditions (pH = 2, 5, 7) in order to mimic the natural context. The adsorption efficiency and change in the clay mineral were characterized via a set of complementary experimental techniques (Fourier transform infrared spectroscopy, X-ray diffraction, elemental analyses). Adsorption isotherms at the equilibrium were fitted with the models of Langmuir, Freundlich and Dubinin-Radushkevitch allowing one to precisely quantify the adsorption through the derived fitting parameters. From the adsorption data combined with complementary results of the modeled humic-clay complexes, different types of interactional mechanisms were inferred as a function of background acidity: (i) at pH = 2 while protonated GA was the preponderant form, anionic GA species can be adsorbed to the Na–Mt surface through electrostatic interaction, leading to the a slight covering of the clay surface favoring in a second step the GA adsorption by π-π and Van der Waals forces; XRD patterns corroborated via TGA and FT/IR results suggested the actual intercalation of the phenolic acid within the interlayer space; (ii) At pH = 5, above the pKa of phenolic acid, only 20% of the protonated form subsisted and these species were adsorbed via coordinative bonding, without however any perceptible intercalation; (iii) and in the regime with neutral environment (pH = 7), the preponderance of GA anionic species led to a poor adsorption which appeared to be only located at the external surface of the clay mineral.

AB - For a better understanding of the preservation of organic matter in clay minerals, the adsorption of a model humic substance, the Gallic Acid (GA), onto a Na-montmorillonite (Na–Mt) was performed in batch situation for various experimental conditions (pH = 2, 5, 7) in order to mimic the natural context. The adsorption efficiency and change in the clay mineral were characterized via a set of complementary experimental techniques (Fourier transform infrared spectroscopy, X-ray diffraction, elemental analyses). Adsorption isotherms at the equilibrium were fitted with the models of Langmuir, Freundlich and Dubinin-Radushkevitch allowing one to precisely quantify the adsorption through the derived fitting parameters. From the adsorption data combined with complementary results of the modeled humic-clay complexes, different types of interactional mechanisms were inferred as a function of background acidity: (i) at pH = 2 while protonated GA was the preponderant form, anionic GA species can be adsorbed to the Na–Mt surface through electrostatic interaction, leading to the a slight covering of the clay surface favoring in a second step the GA adsorption by π-π and Van der Waals forces; XRD patterns corroborated via TGA and FT/IR results suggested the actual intercalation of the phenolic acid within the interlayer space; (ii) At pH = 5, above the pKa of phenolic acid, only 20% of the protonated form subsisted and these species were adsorbed via coordinative bonding, without however any perceptible intercalation; (iii) and in the regime with neutral environment (pH = 7), the preponderance of GA anionic species led to a poor adsorption which appeared to be only located at the external surface of the clay mineral.

KW - Adsorption

KW - Montmorillonite

KW - Organic matter preservation

KW - Phenolic acids

UR - http://www.scopus.com/inward/record.url?scp=85067674057&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85067674057&partnerID=8YFLogxK

U2 - 10.1016/j.clay.2019.105188

DO - 10.1016/j.clay.2019.105188

M3 - Article

VL - 180

JO - Applied Clay Science

JF - Applied Clay Science

SN - 0169-1317

M1 - 105188

ER -