scholarly journals Effect of Anions (Cl−, SO2−4) on the Interfacial Properties of Akaganeite (β-FeOOH) in Aqueous Electrolyte Solutions

1988 ◽  
Vol 5 (4) ◽  
pp. 257-279 ◽  
Author(s):  
K.M. Parida
Keyword(s):  
Aqueous Electrolyte ◽  
Surface Acidity ◽  
Aqueous Media ◽  
Electrolyte Solutions ◽  
Chloride Ions ◽  
Point Of Zero Charge ◽  
Surface Complexes ◽  
Solution Interface ◽  
Adsorption Data ◽  
Titration Data

The point of zero charge (pHpzc) of the sample (β-FeOOH) is shifted from 7.50 to 8.20 and 8.55, respectively, in KCl and K2SO4 electrolyte media. Intrinsic surface acidity and complexation constants have been calculated by single and double extrapolation methods using Potentiometrie titration data obtained for different concentrations of KCl and K2SO4 in aqueous media. Complexation con stants for K+, Cl− and SO2−4 have also been calculated from adsorption data by the same two methods. Close agreement exists between the two sets of values. Chloride ions form SOH2−4 – Cl− surface complexes on a β-FeOOH surface, whereas sulphate ions form two types of surface complex i.e. SOH+2 – SO2−4 and SOH+2 – SO4H−. Various parameters such as σ0, ψ0, ψd, dσ0/dψ0, etc. associated with the electrical double layer at the oxide/aqueous KCl and K2SO4 electrolyte solution interface have been calculated from Potentiometrie and adsorption data, and are discussed.

Specific counter-cation effect on the molecular orientation of thiocyanate anions at the aqueous solution interface

2020 ◽  
Vol 22 (18) ◽  
pp. 10106-10115
Author(s):  
Hongxing Hao ◽  
Qing Xie ◽  
Jingwen Ai ◽  
Yuan Wang ◽  
Hongtao Bian
Keyword(s):  
Aqueous Solution ◽  
Atmospheric Aerosols ◽  
Molecular Orientation ◽  
Aqueous Electrolyte ◽  
Electrolyte Solutions ◽  
Interfacial Structure ◽  
Cation Effect ◽  
Solution Interface ◽  
Wide Range ◽  
Counter Cation

Understanding the interfacial structure of aqueous electrolyte solutions is important and relevant to a wide range of systems, ranging from atmospheric aerosols to electrochemistry, and biological environments.

scholarly journals Cation-Exchange Properties of Aluminium(III) Phosphate

1996 ◽  
Vol 13 (4) ◽  
pp. 261-279 ◽  
Author(s):  
S. Mustafa ◽  
A. Naeem ◽  
N. Rehana ◽  
H.Y. Samad
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Thermodynamic Parameters ◽  
Metal Ion ◽  
Aqueous Electrolyte ◽  
Electrolyte Solutions ◽  
Ion Sorption ◽  
Metal Ion Uptake ◽  
Titration Data ◽  
Exchange Properties

Potentiometric titrations of aluminium(III) phosphate have been performed in the presence of aqueous electrolyte solutions containing Cu2+, Zn2+, Ni2+ and K+ ions as a function of the concentration of the latter, the pH and the temperature. The sorption of Zn2+ ions has also been studied and the data for metal ion sorption shown to correlate with the Potentiometric titration data, indicating that the process responsible for metal ion uptake is ion exchange. The pKa value of the exchanger and its thermodynamic parameters have been evaluated.

A Poisson–Boltzmann treatment of the capacitance of a layer of symmetrical spherical dipoles

1978 ◽  
Vol 56 (6) ◽  
pp. 861-868 ◽  
Author(s):  
Penny Dalrymple-Alford ◽  
Keith B. Oldham
Keyword(s):  
Charge Distribution ◽  
Electrolyte Solution ◽  
Applied Field ◽  
Potential Distribution ◽  
Aqueous Electrolyte ◽  
Aqueous Electrolyte Solution ◽  
Point Of Zero Charge ◽  
One Dimensional ◽  
Solution Interface ◽  
Poisson Boltzmann

The capacitance of a layer of spherical orientable dipoles has been determined. The properties attributed to each dipole are those of two point charges on a diameter of the sphere and equidistant from its centre. A one-dimensional potential distribution is assumed to exist normal to the layer and to be coupled to the charge distribution via Poisson's law. The orientation of the dipoles is random in the absence of polarization, but is taken as governed by Boltzmannian statistics when an applied field is present. The treatment predicts that the capacitance will display a pronounced hump at the point of zero charge. Though this study was motivated by a wish to interpret the inner-layer capacitance at a mercury/aqueous electrolyte solution interface, the treatment is shown to be inapplicable quantitatively to such a system.

Kinetic medium effects. II. Hydrolysis of esters in electrolyte solutions

1965 ◽  
Vol 18 (12) ◽  
pp. 1943 ◽  
Author(s):  
PT McTigue ◽  
AR Watkins
Keyword(s):  
Rate Constants ◽  
Butyl Acetate ◽  
Aqueous Electrolyte ◽  
Aqueous Media ◽  
Electrolyte Solutions ◽  
Hydration Numbers ◽  
Medium Effects ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of ◽  
Methyl Chloroacetate

Rate constants have been measured for the acid-catalysed hydrolyses of t-butyl acetate and methyl chloroacetate in various aqueous electrolyte solutions; the activity coefficients of the esters in these electrolyte solutions have also been measured. The results are used to test a recently proposed method of determining transition state hydration numbers for reactions in aqueous media.

Promoting Nitrogen Electroreduction to Ammonia with Bismuth Nanocrystals and Potassium Cations in Water

2020 ◽  
Author(s):  
Jaecheol Choi ◽  
Hoang-Long Du ◽  
Manjunath Chatti ◽  
Bryan H. R. Suryanto ◽  
Alexandr Simonov ◽  
...  
Keyword(s):  
Electrocatalytic Activity ◽  
Aqueous Electrolyte ◽  
Electrolyte Solutions ◽  
Reduction Reaction ◽  
Nitrogen Reduction ◽  
Aqueous Electrolyte Solutions

We demonstrate that bismuth exhibits no measurable electrocatalytic activity for the nitrogen reduction reaction to ammonia in aqueous electrolyte solutions, contrary to several recent reports on the highly impressive rates of Bi-catalysed electrosynthesis of NH<sub>3</sub> from N<sub>2</sub>.

scholarly journals A four-electron Zn-I2 aqueous battery enabled by reversible I−/I2/I+ conversion

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yiping Zou ◽  
Tingting Liu ◽  
Qijun Du ◽  
Yingying Li ◽  
Haibo Yi ◽  
...  
Keyword(s):  
Aqueous Electrolyte ◽  
Chloride Ions ◽  
Experimental Characterization ◽  
Redox Couples ◽  
Free Chloride ◽  
Reversible Redox ◽  
Aqueous Battery ◽  
Storage Batteries ◽  
Aqueous Batteries ◽  
Superior Level

AbstractElectrochemically reversible redox couples that embrace more electron transfer at a higher potential are the eternal target for energy storage batteries. Here, we report a four-electron aqueous zinc-iodine battery by activating the highly reversible I2/I+ couple (1.83 V vs. Zn/Zn2+) in addition to the typical I−/I2 couple (1.29 V). This is achieved by intensive solvation of the aqueous electrolyte to yield ICl inter-halogens and to suspend its hydrolysis. Experimental characterization and modelling reveal that limited water activity and sufficient free chloride ions in the electrolyte are crucial for the four-electron process. The merits of the electrolyte also afford to stabilize Zn anode, leading to a reliable Zn-I2 aqueous battery of 6000 cycles. Owing to high operational voltage and capacity, energy density up to 750 Wh kg−1 based on iodine mass was achieved (15–20 wt% iodine in electrode). It pushes the Zn-I2 battery to a superior level among these available aqueous batteries.

scholarly journals Thermodynamic Study on the Dissociation and Complexation of Coumarinic Acid with Neodymium(III) and Dioxouranium(VI) in Aqueous Media

2021 ◽  
Vol 11 (10) ◽  
pp. 4475
Author(s):  
Luana Malacaria ◽  
Giuseppina Anna Corrente ◽  
Emilia Furia
Keyword(s):  
Protonation Constant ◽  
Aqueous Media ◽  
Metal Cations ◽  
Natural Antioxidants ◽  
Ion Concentration ◽  
Basic Salt ◽  
Hydrogen Ion Concentration ◽  
Overall Stability ◽  
Titration Data ◽  
Metal Ratio

In the frame of a systematic study on the sequestering ability of natural antioxidants towards metal cations, the complexation of coumarin-3-carboxilic acid (HCCA) with neodymium(III) and dioxouranium(VI) (uranyl, UO22+), and overall stability constants of the resulting complexes, were evaluated from the pH-potentiometric titration data at 37 °C and in an aqueous solution (i.e., 0.16 mol/L NaClO4). The graphic representation of the complex’s concentration curves is given by the distribution diagrams, which provide a depiction of all the species present in the solution in the selected pH ranges. The protonation constant of HCCA was also determined to evaluate the competition of the ligand for the metal cations and H+. The ligand-to-metal concentration ratio was varied between 1 and 10, and the hydrogen ion concentration was decreased stepwise until the incipient precipitation of a basic salt of the metal, which occurred at different values depending on the specific metal cation and the ligand to metal ratio. Speciation profiles obtained by potentiometric titrations and supported by UV-Vis data show that a complexation occurs at a ligand-to-Nd(III) and to –UO22+ ratio of 1:1 and 2:1, with different degrees of deprotonation: Nd(OH)(CCA)+, UO2(OH)(CCA), UO2(OH)2(CCA)−, and Nd(OH)(CCA)2, UO2(CCA)2 and (UO2)2(OH)2(CCA)2.

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