Humidity effect on ion behaviors of moisture-driven CO2 sorbents

Xiaoyang Shi, Hang Xiao, Xiangbiao Liao, Mitchell Armstrong, Xi Chen, Klaus Lackner

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Ion hydration is a fundamental process in many natural phenomena. This paper presents a quantitative analysis, based on atomistic modeling, of the behavior of ions and the impact of hydration in a novel CO2 sorbent. We explore moisture-driven CO2 sorbents focusing on diffusion of ions and the structure of ion hydration complexes forming inside water-laden resin structures. We show that the stability of the carbonate ion is reduced as the water content of the resin is lowered. As the hydration cloud of the carbonate ion shrinks, it becomes energetically favorable to split a remaining water molecule and form a bicarbonate ion plus a hydroxide ion. These two ions bind less water than a single, doubly charged carbonate ion. As a result, under relatively dry conditions, more OH- ions are available to capture CO2 than in the presence of high humidity. Local concentrations of dissolved inorganic carbon and water determine chemical equilibria. Reaction kinetics is then driven to a large extent by diffusion rates that allow water and anions to move through the resin structure. Understanding the basic mechanics of chemical equilibria and transport may help us to rationally design next-generation efficient moisture-driven CO2 sorbents.

Original languageEnglish (US)
Article number164708
JournalJournal of Chemical Physics
Issue number16
StatePublished - Oct 28 2018

ASJC Scopus subject areas

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry


Dive into the research topics of 'Humidity effect on ion behaviors of moisture-driven CO2 sorbents'. Together they form a unique fingerprint.

Cite this