Calorimetric study of alkali and alkaline-earth cation adsorption and exchange at the quartz-solution interface

Nicholas Allen, Michael L. Machesky, David J. Wesolowski, Nadine Kabengi

Research output: Contribution to journalArticlepeer-review

Abstract

Cations in natural solutions significantly impact interfacial processes, particularly dissolution and surface charge measurements for quartz and silica, which are amongst the most naturally abundant and technologically important solids. Thermodynamic parameters for cation-specific interfacial reactions have heretofore been mostly derived instead of directly measured experimentally. This work investigates the energetics of adsorption and exchange reactions of alkali metal (M+) and alkaline earth (M2+) cations with the quartz surface by flow adsorption microcalorimetry, in tandem with in-situ pH measurements. The magnitudes of the heats of adsorption and exchange were found to increase along the Hofmeister series i.e., Li+ < Na+ < K+ < Rb+ < Cs+ and Mg2+ < Ca2+ < Sr2+ < Ba2+, and exhibited strong correlations to bulk cation hydration enthalpies (ΔHhyd). These results suggest inner-sphere adsorption for all studied cations and highlight the role ΔHhyd plays in rationalizing these reactions and controlling their net overall enthalpy. pH measurements demonstrate that quartz surface charge will vary depending on the cation present, as is well known for amorphous forms of silica. Along with calorimetric signals, pH data revealed kinetic differences between the adsorption and desorption reactions of M+ and M2+, and individual cations within each group.

Original languageEnglish (US)
Pages (from-to)538-548
Number of pages11
JournalJournal of Colloid And Interface Science
Volume504
DOIs
StatePublished - Oct 15 2017

Keywords

  • Cation adsorption
  • Cation adsorption enthalpy
  • Cation exchange
  • Energetics
  • Flow microcalorimetry
  • Quartz
  • Thermodynamics

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

Fingerprint Dive into the research topics of 'Calorimetric study of alkali and alkaline-earth cation adsorption and exchange at the quartz-solution interface'. Together they form a unique fingerprint.

Cite this