Structures of ions accommodated in salty ice Ih crystals

Yashima, Yuga; Okada, Yusuke; Harada, Makoto; Okada, Tetsuo

doi:10.1039/d1cp01624e

Cited by 9 publications

(4 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our recent study indicated that K + or Cl – replaces one water molecule in the ice Ih crystal lattice. The surrounding water molecule rotates to coordinate K + via a lone pair of the oxygen atom or interact with Cl – via a hydrogen atom . As illustrated in Figure , ion uptake generates additional Bjerrum defects, which enhance the pH-buffering capacity in the ice/FCS system.…”

Section: Resultsmentioning

confidence: 99%

pH-Buffering Capacity of Ice

2022

Self Cite

View full text Add to dashboard Cite

The pH of frozen solutions is a key parameter for some environmentally important reactions that occur in the cryosphere including atmospheric ice clouds because the pH affects the reaction equilibria and kinetics. Several studies reported interesting behavior of acidic or basic compounds on the ice surface and discussed them in relation to the quasi-liquid layer (QLL). We have found that the peculiar acid−base behavior in frozen systems is not unique to the QLL but is also seen in the freezeconcentrated solution (FCS), which is separated from ice upon the freezing of an aqueous solution. For example, when a dilute HCl prepared in aqueous NaCl is frozen, the pH value measured is larger than that predicted from the freeze concentration ratio. Similarly, the pH of buffer solutions shifts toward the neutral pH upon freezing, and this effect is more pronounced at higher freeze concentration ratios and lower buffer concentrations. These findings suggest that the ice/FCS system has a pH-buffering capacity at around neutral pH. The formation and elimination of the Bjerrum defects in the ice crystal near the FCS interface are discussed as the origin of the pH buffering.

show abstract

Section: Resultsmentioning

confidence: 99%

pH-Buffering Capacity of Ice

2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…These hydrates take the role of a secondary phase, pinning the grain boundaries when they migrate and thereby further impeding the process of grain growth. Despite ice's pronounced repelling effect on salt ions, prior experiments have demonstrated that chlorides, such as KCl and NaCl, can be uniformly distributed as solutes within ice lattice, at exceedingly low concentrations (10 −5 to 10 −4 mol L −1 ) (Montagnat et al, 2001;Yashima et al, 2021). However, sulfates have been found to concentrate along grain boundaries rather than within the ice lattice (Montagnat et al, 2001).…”

Section: Below the Eutectic Temperaturementioning

confidence: 99%

“…Given that Cl − ions can integrate into the interior of the ice crystal lattice, chloride salts exhibit slightly greater solubility in ice than sulfate salts. Specifically, the sol-ubility of KCl is approximately 2 to 3 × 10 −5 mol L −1 (Yashima et al, 2021), while NaCl's solubility ranges from 3 × 10 −5 to 1 × 10 −4 mol L −1 (Montagnat et al, 2001;Gross et al, 1977). For Ca 2+ and Mg 2+ with smaller ionic radii, we assume that the solubility of their corresponding chlorine salts (CaCl 2 and MgCl 2 ) in the ice lattice is of the same order as KCl and NaCl, that is, at least greater than 1 × 10 −5 mol L −1 .…”

Section: Implications For Natural Icementioning

confidence: 99%

Grain growth of ice doped with soluble impurities

Wang,

Fan,

2024

The Cryosphere

View full text Add to dashboard Cite

Abstract. The grain size of polycrystalline ice affects key parameters related to the dynamics of ice masses, such as the rheological and dielectric properties of terrestrial ice as well as the ice shells of icy satellites. To investigate the effect of soluble impurities on the grain-growth kinetics of polycrystalline ice, we conducted annealing experiments on polycrystalline ice samples doped with different concentrations of KCl (10−2, 10−3, 10−4 and 10−5 mol L−1) or MgSO4 (10−2 and 10−5 mol L−1). Samples were annealed for a maximum of 100 h at a hydrostatic confining pressure of 20 MPa (corresponding to a depth of about 2 km) and different constant temperatures of 268, 263, 258 and 253 K (corresponding to −5, −10, −15 and −20 °C, respectively). After each experiment, images of a polished sample surface were obtained using an optical microscope equipped with a cold stage. With grain boundaries detected, grains were reconstructed from the images, and an average grain size was determined for each sample. Normal grain growth occurred in all samples. Grain-size data are interpreted using the following grain-growth model: dn-d0n=kt (d: grain size; d0: starting grain size; n: grain-growth exponent; k: growth constant; t: duration). Values of the best-fit grain-growth exponent, n, for all samples range from 2.6 to 6.2, with an average value of 4.7. Pure ice exhibits 3.1 ⩽n⩽ 4.6, with an average value of 3.8. Above the eutectic point, soluble impurities enhance grain growth, as a melt phase is formed, and it could provide a fast diffusion pathway. Below the eutectic point, soluble impurities impede grain growth probably via the formation of salt hydrates that could pin the grain boundaries. Close to the eutectic point, the grain growth of doped ice is similar to pure ice. Natural ice is impure, often containing air bubbles and soluble impurities, and is usually subjected to a hydrostatic pressure. Our data set will provide new insights into the evolution of grain size within and the dynamics of natural ice masses.

show abstract

“…Equilibrated configurations of ions postdynamic relaxation in both the (100) and (002) crystalline planes within a 0.9 nm channel are depicted in Figures a and b. Ion transport across various crystalline planes was influenced by the interaction between the ions and the ice lattice structure. , In the (100) plane, ions interspersed between ice layers led to extensive interactions with the ice lattice, thereby impeding their movement. In contrast, spatial analysis indicated that ions exhibited faster transport along the central pathway of the (002) plane, enhanced by reduced interactions with the ice lattice (Figure S15).…”

mentioning

confidence: 99%

Ultrahigh Lithium Selective Transport in Two-Dimensional Confined Ice

Han,

Jin,

et al. 2024

J. Phys. Chem. Lett.

View full text Add to dashboard Cite

Inspired by selective ion transport in biological membrane proteins, researchers developed artificial ion channels that sieve monovalent cations, catering to the increasing lithium demand. In this work, we engineered an ion transport channel based on the confined ice within two-dimensional (2D) capillaries and found that the permselectivity of monovalent cations depends on the anisotropy of the confined ice. Particularly, the 2D confined ice showed an anomalous lithium selective transport along the (002) direction in the vermiculite capillary, with the Li + /Na + and Li + /K + permselectivity reaching up to 556 ± 86 and 901 ± 172, respectively, superior to most ion-selective channels. However, the 2D confined ice along the (100) direction showed less Li + permselectivity. Additionally, the anisotropy of 2D confined ice can be tuned by adjusting the interlayer spacing. By providing insights into the ion transport in the 2D confined ice, our work may inspire more design of monovalent ion-selective channels for efficient lithium separation.

show abstract

Structures of ions accommodated in salty ice Ih crystals

Abstract: Frozen aqueous electrolytes are ubiquitous and involved in various phenomena occurring in the natural environment. Although salts are expelled from ice during freezing of aqueous solutions, minor amounts of the...

Cited by 9 publications

References 44 publications

pH-Buffering Capacity of Ice

pH-Buffering Capacity of Ice

Grain growth of ice doped with soluble impurities

Ultrahigh Lithium Selective Transport in Two-Dimensional Confined Ice

Contact Info

Product

Resources

About