Chemistry of ice: Migration of ions and gases by directional freezing of water

Shafique, Umer; Anwar, Jamil; Munawar, Munawar Ali; Zaman, Waheed; Rehman, Rabia; Dar, Amara; Salman, Muhammad; Saleem, Mahmood; Shahid, Naeema; Akram, Mehwish; Naseer, Arooj; Jamil, Nadia

doi:10.1016/j.arabjc.2011.02.019

Cited by 26 publications

(11 citation statements)

References 19 publications

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“…It is evident that the amount of migrated salt to the upper part of the soil column was substantial for the migration along with moving freezing front (Umer et al 2011).The water was the carrier of the salt, so the great number of salt migrated for the convection, and the amount of salt diffused due to the concentration gradient was little. Therefore, the migration of the water and the salt was the result of the temperature gradient which existed since the experiments began.…”

Section: Resultsmentioning

confidence: 90%

Cyclic freeze–thaw as a mechanism for water and salt migration in soil

Bing

Zhang

2015

Environ Earth Sci

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Freeze-thaw action acts as a controlling mechanism for redistributing soil water and salt. The paper focuses on the factors that influence soil water and salt migration and uses experimental results to analyze the mechanism of cyclic freeze-thaw in which the temperature gradient is the principal factor for water and salt transfer. Salt redistribution in soil occurs as a result of the integrated effects of convection, diffusion, and numerous chemical and physicochemical processes.

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Section: Resultsmentioning

confidence: 90%

Cyclic freeze–thaw as a mechanism for water and salt migration in soil

Bing

Zhang

2015

Environ Earth Sci

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“…For the lowest H2SO4 concentration measured, 0.1 M, the pH should be <1, and the VO 2+ structure should be stable as an aquo-cation ligated by five water molecules [27]. The increased presence of additional ions in the solution must also play a role in deterring aggregation upon freezing, possibly by adding competition to ion redistribution observed in freezing liquids [28]. The initial parameters for fitting the higher temperature spectra were determined by fits to the frozen spectra at −180 °C.…”

Section: Resultsmentioning

confidence: 98%

The Effect of Sulfuric Acid Concentration on the Physical and Electrochemical Properties of Vanadyl Solutions

et al. 2018

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The effects of sulfuric acid concentration in VO2+ solutions were investigated via electrochemical methods and electron paramagnetic resonance. The viscosity of solutions containing 0.01 M VOSO4 in 0.1–7.0 M H2SO4 was measured. Diffusion coefficients were independently measured via electrochemical methods and electron paramagnetic resonance (EPR), with excellent agreement between the techniques employed and literature values. Analysis of cyclic voltammograms suggest the oxidation of VO2+ to VO2+ is quasi-reversible at high H2SO4 concentrations (>5 mol/L), and approaching irreversible at lower H2SO4 concentrations. Further analysis reveals a likely electrochemical/chemical (EC) mechanism where the H2SO4 facilitates the electrochemical step but hinders the chemical step. Fundamental insights of VO2+/H2SO4 solutions can lead to a more comprehensive understanding of the concentration effects in electrolyte solutions.

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“…In addition, the direction of water and salt migration is an important issue for saline soil. Shafique et al (2016) have found that ice crystals push salt ions towards the opposite direction of crystal growth in cooling solution. The solution concentration increases gradually because the molecules of solute are rejected into the unfrozen water (Banin and Anderson 1974;Panday 1991;Shafique et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Water and Salt Migration with Phase Change in Saline Soil during Freezing and Thawing Processes

Wu¹,

Zhou

Xingyuan

2017

Groundwater

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Water and salt transfer coupled with phase change may cause serious damage to engineering structures in saline soil regions. In this study, the migration of water and salt in silty clay collected from the Qinghai-Tibet Plateau is explored experimentally and numerically during freezing and thawing processes. The results revealed that there are significant differences in the variations of liquid water content and solution concentration for different initial salt contents, due to salt crystallization and dissolution. The temperature-induced water migration is determined by the soil properties, which can be well explained by the thermodynamics of mass transfer. The amount of salt migrated upward during cooling is slightly larger than that transported downward in the warming period, implying that salt may be accumulated in the surface soil after a large number of circulations and finally result in soil salinization.

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Chemistry of ice: Migration of ions and gases by directional freezing of water

Cited by 26 publications

References 19 publications

Cyclic freeze–thaw as a mechanism for water and salt migration in soil

Cyclic freeze–thaw as a mechanism for water and salt migration in soil

The Effect of Sulfuric Acid Concentration on the Physical and Electrochemical Properties of Vanadyl Solutions

Water and Salt Migration with Phase Change in Saline Soil during Freezing and Thawing Processes

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