scholarly journals New Data on Activity Coefficients of Potassium, Nitrate, and Chloride Ions in Aqueous Solutions of KNO3 and KCl by Ion Selective Electrodes

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Debasmita Dash ◽  
Shekhar Kumar ◽  
C. Mallika ◽  
U. Kamachi Mudali
Keyword(s):  
Activity Coefficient ◽  
Aqueous Solutions ◽  
Activity Coefficients ◽  
Reference Electrode ◽  
Potassium Nitrate ◽  
Chloride Ions ◽  
Ion Selective Electrodes ◽  
Ion Activity ◽  
Double Junction ◽  
Single Ion Activity

Ion selective electrodes (ISEs) are used to measure the single-ion activity coefficients in aqueous solutions of KNO3 and KCl at 298.15 K against a double-junction reference electrode. The EMF responses of ISEs up to 0.01 m are plotted to obtain the slope and intercept values. The obtained slopes and intercepts are used in Nernst equation for higher concentrated solutions for calculation of individual ion activity coefficient. The mean ionic activity coefficients are estimated from single ion activity coefficient, and the obtained results are compared with the literature values.

Single ion activity coefficients based on the electrical double-layer model. Na2SO4 aqueous solutions

1983 ◽  
Vol 28 (11) ◽  
pp. 1539-1544 ◽  
Author(s):  
Angelo Uzzo ◽  
Anna Daghetti ◽  
Sergio Trasatti
Keyword(s):  
Aqueous Solutions ◽  
Double Layer ◽  
Activity Coefficients ◽  
Electrical Double Layer ◽  
Layer Model ◽  
Ion Activity ◽  
Double Layer Model ◽  
Single Ion Activity

scholarly journals Towards the Understanding of Water-in-Salt Electrolytes: Individual Ion Activities and Liquid Junction Potentials in Highly Concentrated Aqueous Solutions

2021 ◽  
Author(s):  
Damien Degoulange ◽  
Nicolas Dubouis ◽  
Alexis Grimaud
Keyword(s):  
Activity Coefficients ◽  
Operating Voltage ◽  
Redox Potentials ◽  
Liquid Junction ◽  
Nernst Potential ◽  
Concentrated Electrolytes ◽  
Ion Activity ◽  
Ion Activities ◽  
Single Ion Activity ◽  
Increased Activity

Highly concentrated electrolytes were recently proposed to improve the performances of aqueous electrochemical systems by delaying the water splitting and increasing the operating voltage for battery applications. While advances were made regarding their implementation in practical devices, debate exists regarding the physical origin for the delayed water reduction occurring at the electrode/electrolyte interface. Evidently, one difficulty resides in our lack of knowledge regarding ions activity arising from this novel class of electrolyte, it being necessary to estimate the Nernst potential of associated redox reactions such as Li<sup>+</sup> intercalation or the hydrogen evolution reaction. In this work, we first measured the potential shift of electrodes selective to either Li<sup>+</sup>, H<sup>+</sup> or Zn<sup>2+</sup> ions from diluted to highly concentrated regimes in LiCl or LiTFSI solutions. Observing similar shifts for these different cations and environments, we establish that shifts in redox potentials from diluted to highly concentrated regime originates in large from an increase junction potential, it being dependent on the ions activity coefficients that increase with concentration. While our study shows that single ion activity coefficients, unlike mean ion activity coefficients, cannot be captured by any electrochemical means, we demonstrate that protons concentration increases by approximatively two orders of magnitude from 1 mol.kg<sup>-1</sup> to 15-20 mol.kg<sup>-1</sup> solutions. Combined with the increased activity coefficients, this increases the activity of protons and thus the pH of highly concentrated solutions which appears acidic.

Research on Thermodynamic Properties of Bioleaching Solution in Lean Nickel-Cobalt Ore by Pitzer - Meissner Model

2015 ◽  
Vol 1092-1093 ◽  
pp. 1455-1459
Author(s):  
Chu Yue Hou ◽  
Gui Ying Zhou ◽  
Jian Kang Wen ◽  
Biao Wu
Keyword(s):  
Thermodynamic Properties ◽  
Activity Coefficient ◽  
Aqueous Solutions ◽  
Activity Coefficients ◽  
Pitzer Model ◽  
Foreign Ions ◽  
Nickel Cobalt

In this paper, we jointly use the Pitzer model and the Meissner model to study thermodynamic laws of bioleaching solution in a lean nickel-cobalt ore in the Jilin Baishan, by using the Pitzer model to calculate activity coefficients of single electrolyte aqueous solutions and the Meissner model to calculate activity coefficients of components in the bioleaching solution. Also we studied the rules of activity coefficient of NiSO4 and CoSO4 in the solution. Results show that when separating and purifying foreign ions from bioleaching solution of the lean nickel-cobalt ore, the descending sequence of their ion concentration’s effect over the solution is Mg2+, Fe3+, Fe2+, Ni2+, Co2+ and Ca2+.

COMPARISON OF ION-SELECTIVE ELECTRODE METHODS FOR DETERMINING POTASSIUM Q/I RELATIONSHIPS

1990 ◽  
Vol 70 (4) ◽  
pp. 693-704 ◽  
Author(s):  
JIAN WANG ◽  
RICHARD E. FARRELL ◽  
A. DUNCAN SCOTT
Keyword(s):  
Concentration Ratio ◽  
Electrochemical Cell ◽  
Reference Electrode ◽  
Salt Bridge ◽  
Ion Selective Electrodes ◽  
Combined Approach ◽  
Selective Electrode ◽  
Liquid Junction ◽  
Double Junction ◽  
Cr Concentration

Methods of characterizing the K + status of soils in terms of quantity-intensity (Q/I) relationships usually entail lengthy equilibration periods, filtrations, and multiple analyses of the filtrates. It has been established, however, that simpler and less time-consuming methods of determining Q/I parameters can be devised with ion-selective electrodes (ISEs). To this end, different ISE methods were developed and evaluated with suspensions of three Iowa soils and a successive-additions method of varying the added K+. The ISE methods, which were categorized on the basis of the electrochemical cell involved, were tested for their applicability to soil suspensions. Specifically, single-ISE (K- and Ca-ISEs vs. a double-junction reference electrode assembly with a 10 M LiOAc salt bridge), dual-ISE (K-ISE vs. Ca-ISE), and triple-ISE (K- and Ca-ISEs vs. Cl-ISE) methods were compared to ascertain the best means of determining the ΔK (gain or loss of dissolved K) and CR [concentration ratio: CK/(CCa+Mg)1/2] terms of the Q/I relationships. The Q/I curves for the three soils and the specific parameters of Q/I relationships were also determined with the different ISE methods. It was concluded that the combined approach of using the triple-ISE method with soil suspensions offers the best means of carrying out simple, rapid, and liquid junction free determinations of potassium Q/I relationships. Key words: Electrochemical cell, liquid junction, concentration ratio, potential buffering capacity

Activity coefficients of DL-valine in aqueous solutions of KCl at 25�C. Measurement with ion selective electrodes and modelling

1996 ◽  
Vol 25 (9) ◽  
pp. 865-875 ◽  
Author(s):  
Mohammad K. Khoshkbarchi ◽  
Juan H. Vera
Keyword(s):  
Aqueous Solutions ◽  
Activity Coefficients ◽  
Ion Selective Electrodes

Measurement and correlation of ion activity coefficients in aqueous solutions of mixed electrolyte with a common ion

1996 ◽  
Vol 121 (1-2) ◽  
pp. 253-265 ◽  
Author(s):  
M.K. Khoshkbarchi ◽  
J.H. Vera
Keyword(s):  
Aqueous Solutions ◽  
Activity Coefficients ◽  
Mixed Electrolyte ◽  
Ion Activity ◽  
Common Ion
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