Mechanisms of surface charge modication of carbonates in aqueous electrolyte solutions

Maryam H. Derkani, Ashleigh J. Fletcher, Maxim Fedorov, Wael Abdallah, Bastian Sauerer, James Anderson, Zhenyu J. Zhang

Research output: Contribution to journalArticle

Abstract

The influence of different types of salts (NaCl, CaCl2, MgCl2, NaHCO3, and Na2SO4) on the surface characteristics of unconditioned calcite and dolomite particles, and conditioned with stearic acid, were investigated. This study used zeta potential measurements to gain fundamental understanding of physico-chemical mechanisms involved in surface charge modication of carbonate minerals in the presence of diluted brines. By increasing the salt concentration of divalent cationic salt solution (CaCl2 and MgCl2), zeta potential of calcite particles is altered, resulting in charge reversal from negative to positive, while dolomite particles maintained positive zeta potential. This is due to the adsorption of potential determining cations (Ca2+ and Mg2+), and consequent changes in the structure of the diuse layer, predominantly driven by coulombic interactions. While chemical adsorption of potential determining anions (HCO3- and SO42-), maintained negative zeta potential of carbonate surfaces and increased its magnitude up to 10 mM, before decreasing at higher salt concentrations. Physisorption of stearic acid molecules on the calcite and dolomite surfaces changes the zeta potential to more negative values in all solutions. It is argued that divalent cations (Ca2+ and Mg2+) would result in positive and neutral complexes with stearic acid molecules, which may result in strongly bound stearic acid film, whereas ions resulting in negative mineral surface charges (SO42- and HCO3-) will result in loosely bound stearic acid film to the carbonate mineral surfaces. The suggested mechanism for surface charge modication of carbonates, in the presence of different ions, is changes in diffuse layer structure as a result of ion adsorption to the crystal lattice by having a positive contribution to the disjoining pressures when changing electrolyte concentration. This work extends the current knowledge base for dynamic water injection design by determining the effect of salt concentration on surface electrostatics.
LanguageEnglish
JournalColloids and Interfaces
Publication statusAccepted/In press - 22 Oct 2019

Fingerprint

Stearic acid
Carbonates
Zeta potential
Surface charge
Electrolytes
Salts
Calcium Carbonate
Calcite
Carbonate minerals
Magnesium Chloride
Ions
Adsorption
Positive ions
Brines
Molecules
Physisorption
Water injection
Divalent Cations
Crystal lattices
Anions

Keywords

  • calcite
  • dolomite
  • stearic acid
  • zeta potential
  • electric double layer
  • disjoining pressure
  • wettability mechanism
  • low salinity waterflooding

Cite this

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title = "Mechanisms of surface charge modication of carbonates in aqueous electrolyte solutions",
abstract = "The influence of different types of salts (NaCl, CaCl2, MgCl2, NaHCO3, and Na2SO4) on the surface characteristics of unconditioned calcite and dolomite particles, and conditioned with stearic acid, were investigated. This study used zeta potential measurements to gain fundamental understanding of physico-chemical mechanisms involved in surface charge modication of carbonate minerals in the presence of diluted brines. By increasing the salt concentration of divalent cationic salt solution (CaCl2 and MgCl2), zeta potential of calcite particles is altered, resulting in charge reversal from negative to positive, while dolomite particles maintained positive zeta potential. This is due to the adsorption of potential determining cations (Ca2+ and Mg2+), and consequent changes in the structure of the diuse layer, predominantly driven by coulombic interactions. While chemical adsorption of potential determining anions (HCO3- and SO42-), maintained negative zeta potential of carbonate surfaces and increased its magnitude up to 10 mM, before decreasing at higher salt concentrations. Physisorption of stearic acid molecules on the calcite and dolomite surfaces changes the zeta potential to more negative values in all solutions. It is argued that divalent cations (Ca2+ and Mg2+) would result in positive and neutral complexes with stearic acid molecules, which may result in strongly bound stearic acid film, whereas ions resulting in negative mineral surface charges (SO42- and HCO3-) will result in loosely bound stearic acid film to the carbonate mineral surfaces. The suggested mechanism for surface charge modication of carbonates, in the presence of different ions, is changes in diffuse layer structure as a result of ion adsorption to the crystal lattice by having a positive contribution to the disjoining pressures when changing electrolyte concentration. This work extends the current knowledge base for dynamic water injection design by determining the effect of salt concentration on surface electrostatics.",
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author = "Derkani, {Maryam H.} and Fletcher, {Ashleigh J.} and Maxim Fedorov and Wael Abdallah and Bastian Sauerer and James Anderson and Zhang, {Zhenyu J.}",
year = "2019",
month = "10",
day = "22",
language = "English",
journal = "Colloids and Interfaces",
issn = "2504-5377",

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Mechanisms of surface charge modication of carbonates in aqueous electrolyte solutions. / Derkani, Maryam H.; Fletcher, Ashleigh J.; Fedorov, Maxim; Abdallah, Wael; Sauerer, Bastian; Anderson, James; Zhang, Zhenyu J.

In: Colloids and Interfaces, 22.10.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Mechanisms of surface charge modication of carbonates in aqueous electrolyte solutions

AU - Derkani, Maryam H.

AU - Fletcher, Ashleigh J.

AU - Fedorov, Maxim

AU - Abdallah, Wael

AU - Sauerer, Bastian

AU - Anderson, James

AU - Zhang, Zhenyu J.

PY - 2019/10/22

Y1 - 2019/10/22

N2 - The influence of different types of salts (NaCl, CaCl2, MgCl2, NaHCO3, and Na2SO4) on the surface characteristics of unconditioned calcite and dolomite particles, and conditioned with stearic acid, were investigated. This study used zeta potential measurements to gain fundamental understanding of physico-chemical mechanisms involved in surface charge modication of carbonate minerals in the presence of diluted brines. By increasing the salt concentration of divalent cationic salt solution (CaCl2 and MgCl2), zeta potential of calcite particles is altered, resulting in charge reversal from negative to positive, while dolomite particles maintained positive zeta potential. This is due to the adsorption of potential determining cations (Ca2+ and Mg2+), and consequent changes in the structure of the diuse layer, predominantly driven by coulombic interactions. While chemical adsorption of potential determining anions (HCO3- and SO42-), maintained negative zeta potential of carbonate surfaces and increased its magnitude up to 10 mM, before decreasing at higher salt concentrations. Physisorption of stearic acid molecules on the calcite and dolomite surfaces changes the zeta potential to more negative values in all solutions. It is argued that divalent cations (Ca2+ and Mg2+) would result in positive and neutral complexes with stearic acid molecules, which may result in strongly bound stearic acid film, whereas ions resulting in negative mineral surface charges (SO42- and HCO3-) will result in loosely bound stearic acid film to the carbonate mineral surfaces. The suggested mechanism for surface charge modication of carbonates, in the presence of different ions, is changes in diffuse layer structure as a result of ion adsorption to the crystal lattice by having a positive contribution to the disjoining pressures when changing electrolyte concentration. This work extends the current knowledge base for dynamic water injection design by determining the effect of salt concentration on surface electrostatics.

AB - The influence of different types of salts (NaCl, CaCl2, MgCl2, NaHCO3, and Na2SO4) on the surface characteristics of unconditioned calcite and dolomite particles, and conditioned with stearic acid, were investigated. This study used zeta potential measurements to gain fundamental understanding of physico-chemical mechanisms involved in surface charge modication of carbonate minerals in the presence of diluted brines. By increasing the salt concentration of divalent cationic salt solution (CaCl2 and MgCl2), zeta potential of calcite particles is altered, resulting in charge reversal from negative to positive, while dolomite particles maintained positive zeta potential. This is due to the adsorption of potential determining cations (Ca2+ and Mg2+), and consequent changes in the structure of the diuse layer, predominantly driven by coulombic interactions. While chemical adsorption of potential determining anions (HCO3- and SO42-), maintained negative zeta potential of carbonate surfaces and increased its magnitude up to 10 mM, before decreasing at higher salt concentrations. Physisorption of stearic acid molecules on the calcite and dolomite surfaces changes the zeta potential to more negative values in all solutions. It is argued that divalent cations (Ca2+ and Mg2+) would result in positive and neutral complexes with stearic acid molecules, which may result in strongly bound stearic acid film, whereas ions resulting in negative mineral surface charges (SO42- and HCO3-) will result in loosely bound stearic acid film to the carbonate mineral surfaces. The suggested mechanism for surface charge modication of carbonates, in the presence of different ions, is changes in diffuse layer structure as a result of ion adsorption to the crystal lattice by having a positive contribution to the disjoining pressures when changing electrolyte concentration. This work extends the current knowledge base for dynamic water injection design by determining the effect of salt concentration on surface electrostatics.

KW - calcite

KW - dolomite

KW - stearic acid

KW - zeta potential

KW - electric double layer

KW - disjoining pressure

KW - wettability mechanism

KW - low salinity waterflooding

UR - https://www.mdpi.com/journal/colloids

M3 - Article

JO - Colloids and Interfaces

T2 - Colloids and Interfaces

JF - Colloids and Interfaces

SN - 2504-5377

ER -