Ion association and hydration in 3:2 electrolyte solutions by dielectric spectroscopy: Aluminum sulfate

Schrödle, Simon; Rudolph, Wolfram W.; Hefter, Glenn; Buchner, Richard

doi:10.1016/j.gca.2007.08.026

Cited by 33 publications

(70 citation statements)

References 60 publications

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“…These trends in e 0 and e 00 with frequency are consistent with those observed for all of the M(III) salt solutions in Groups A, B, C and D in this work and those described in the literature for aqueous electrolytic solutions and water. 21,32,34,39,40,42 Such trends are governed by the polarisability of ions and water molecules in solution in response to the electric field. 21,42c As mentioned in the introduction, ionic polarizations are dominant in the frequency range 0.5-2.0 GHz and dipolar mechanisms dominate in the range 2.0-10.0 GHz.…”

Section: Resultsmentioning

confidence: 99%

Understanding the electromagnetic interaction of metal organic framework reactants in aqueous solution at microwave frequencies

Laybourn

Katrib

Palade

et al. 2016

Phys. Chem. Chem. Phys.

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Preparation of metal organic frameworks (MOFs) via microwave heating is becoming increasingly popular due to reduced reaction times and enhanced control of MOF particle size. However, there is little understanding about the detailed interaction of the electric field portion of the wave with reactants during the synthesis of MOFs. In order to overcome this lack of fundamental understanding, information about the dielectric properties of the reactants is required. In this work the dielectric constants (ε') and loss factors (ε'') of benzene-1,4-dicarboxylic acid (H2BDC; also known as terephthalic acid) and a number of M(III) (M = metal) salts dissolved in deionized water were measured as a function of frequency, temperature and concentration and with varying anions and cations. Dielectric data confirm the aqueous M(III) salts to be strong microwave absorbers, particularly at 915 MHz. M(III) salts with mono-anionic ligands (for example chlorides and nitrates) exhibit higher losses than di-anionic salts (sulfates) demonstrating that the former are heated more effectively in an applied microwave field. Of the M(III) salts containing either singly- or doubly-charged anions, those containing Fe(III) have the highest loss indicating that they will heat more efficiently than other M(III) salts such as Cr(III) and Al(III). Interestingly, H2BDC exhibits little interaction with the electric field at microwave frequencies.

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Section: Resultsmentioning

confidence: 99%

Understanding the electromagnetic interaction of metal organic framework reactants in aqueous solution at microwave frequencies

Laybourn

Katrib

Palade

et al. 2016

Phys. Chem. Chem. Phys.

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“…Analysis of dielectric spectra proves to be more complicated, but manageable, if ion-pairs and complex aggregates also contribute to the complex permittivity. 58 For example, a composite of ion-cloud and ion-pair relaxations is manifested through a small relaxation peak at lower frequencies in NaCl aqueous solutions for concentrations above 1 mol/l. 59 In the concentration ranges for the electrolyte systems studied in this work, however, no evidence of creation of strong ion-pairs has been observed.…”

Section: E Complete Model Of Static Permittivitymentioning

confidence: 99%

Static permittivity of environmentally relevant low-concentration aqueous solutions of NaCl, NaNO3, and Na2SO4

Gorji

Bowler

2020

The Journal of Chemical Physics

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In this paper, the result of a systematic study and molecular mechanisms governing the dielectric spectra of aqueous solutions of NaCl, NaNO 3 , and Na 2 SO 4 with environmentally relevant concentrations (∼mmol/l) are presented, for frequencies from 200 MHz up to 20 GHz and at temperature 25.00 ± 0.01 ○ C. The measured spectra were fitted with a Debye relaxation model using a non-linear, weighted, least-squares analysis. Conductivity was measured independently to reduce uncertainty in obtaining other parameters by spectral fitting. Careful experimentation provided dielectric data of sufficiently low uncertainty to enable observation of polarization mechanisms that emerge only in the low-concentration regime. The data were fitted by a concentration-dependent parametric model that includes terms accounting for internal depolarizing fields and the solvent dilution effect (mixture relation), the kinetic depolarization effect, the dielectric saturation effect, and the Debye-Falkenhagen effect that accounts for the contribution of ionic atmosphere polarization. It has been shown that, in NaCl and NaNO 3 solutions at sufficiently low concentrations, the static permittivity increases due to the Debye-Falkenhagen effect. It has also been shown that, to calculate the number of irrotationally bound water molecules ZIB, the measured static permittivity values should be corrected to account for the contributions of kinetic depolarization and Debye-Falkenhagen effects. Otherwise, unrealistic values of ZIB are obtained. An explanation for the different strengths of the Debye-Falkenhagen effect observed for the different electrolyte solutions, essentially due to the electrophoretic effect and coordination number, is also presented.

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“…Our results have focused on elucidating the high degree of complexity in the monomeric Al 3+ hydrolysis products arising from a mechanism dubbed cooperativity among the Al 3+ hydrolytic species. 33 To this end, polymerization of Al 3+ species and interaction with geochemically relevant species 18,20,34,35 have been neglected. In our previous work, our efforts had been restricted to investigations under ambient pressure conditions.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, in our aim to describe pressure induced speciation of aqueous Al 3+ we make no attempt to describe the influence of temperature on these equilibria. While temperature is certainly a relevant variable, its associated phenomena such as ion pairing, which indeed plays a role in such a system, 35 and phase transitions are neglected. Rather, our aim is to firmly establish and describe the qualitative link between monomeric Al 3+ speciation and external pressure via the cooperativity mechanism among monomeric Al 3+ hydrolysis species.…”

Section: Introductionmentioning

confidence: 99%

Pressure induced speciation changes in the aqueous Al³⁺ system

Bogatko

Geerlings

2014

Phys. Chem. Chem. Phys.

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We have developed a simple model for incorporating the influence of external pressure and solution pH into a cluster based (i.e. comprising the central Al(3+) cation and nearest neighbor coordinating H2O and OH(-) ligands) 1st principles approach to investigate the hydrolysis equilibria of aqueous Al(3+) monomeric species in high pressure environments such as are found in the Earth's mantle. Our model is demonstrated to reproduce the well documented bulk chemistry of the aqueous Al(3+) system under ambient conditions, namely the system is dominated at low and high pH by the 6-coordinated aqua species and 4 coordinated hydroxide species, respectively, while all remaining species occupy a narrow intermediate pH range. Coupling this model to changes in solution pH is achieved by using [H3O(+)] as a parameter in the definition of the formation equilibrium constants used; the influence of external pressure is evaluated using Planck's equation. This approach predicts that changes in external pressure will induce drastic changes in the aqueous solubility of these species under high pressure conditions and moderate changes at as low as 5 GPa. Finally, some industrial and geochemical implications of this result are discussed.

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Ion association and hydration in 3:2 electrolyte solutions by dielectric spectroscopy: Aluminum sulfate

Cited by 33 publications

References 60 publications

Understanding the electromagnetic interaction of metal organic framework reactants in aqueous solution at microwave frequencies

Understanding the electromagnetic interaction of metal organic framework reactants in aqueous solution at microwave frequencies

Static permittivity of environmentally relevant low-concentration aqueous solutions of NaCl, NaNO3, and Na2SO4

Pressure induced speciation changes in the aqueous Al³⁺ system

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Ion association and hydration in 3:2 electrolyte solutions by dielectric spectroscopy: Aluminum sulfate

Cited by 33 publications

References 60 publications

Understanding the electromagnetic interaction of metal organic framework reactants in aqueous solution at microwave frequencies

Understanding the electromagnetic interaction of metal organic framework reactants in aqueous solution at microwave frequencies

Static permittivity of environmentally relevant low-concentration aqueous solutions of NaCl, NaNO3, and Na2SO4

Pressure induced speciation changes in the aqueous Al3+ system

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Pressure induced speciation changes in the aqueous Al³⁺ system