Solvent-Independent Electrode Potentials of Solids Undergoing Insertion Electrochemical Reactions: Part II. Experimental Data for Alkynyl–diphosphine Dinuclear Au(I) Complexes Undergoing Electron Exchange Coupled to Anion Exchange

2012 ◽  
Vol 116 (49) ◽  
pp. 25984-25992 ◽  
Author(s):  
Antonio Doménech-Carbó ◽  
Igor O. Koshevoy ◽  
Noemí Montoya ◽  
Tapani A. Pakkanen ◽  
María Teresa Doménech-Carbó
Keyword(s):  
Experimental Data ◽  
Anion Exchange ◽  
Electron Exchange ◽  
Electrochemical Reactions ◽  
Electrode Potentials

Manipulation of Clinical Materials Using AC Electrokinetics

2010 ◽  
Author(s):  
Mandy L. Y. Sin ◽  
Pak Kin Wong
Keyword(s):  
Experimental Data ◽  
Sample Preparation ◽  
Theoretical Prediction ◽  
Fluid Motion ◽  
Lab On A Chip ◽  
Clinical Samples ◽  
Electrochemical Reactions ◽  
Ac Electrokinetics ◽  
Wide Range ◽  
Electrothermal Flow

AC electrokinetics is a promising approach for sample preparation and reaction enhancement in lab-on-a-chip devices. However, relative little has been done on the electrokinetic manipulation of physiological fluids and buffers with similar properties, such as conductivity. Herein, electrokinetic manipulation of fluids with a wide range of conductivities has been studied as a function of voltage and frequency. AC electrothermal flow is determined to dominate the fluid motion when the applied frequency of the AC potential is above 100 kHz. Interestingly, experimental data deviate from theoretical prediction for fluids with high conductivities (> 1 Sm−1). The deviation can be understood by voltage modulated electrochemical reactions and should be accounted for when manipulating clinical materials with high conductivities. The study will provide useful in sights in designing lab-on-a-chip devices for manipulating clinical samples in the future.

scholarly journals Assessment of Constant-Potential Implicit Solvation Calculations of Electrochemical Energy Barriers

2018 ◽  
Author(s):  
Maxime Van den Bossche ◽  
Egill Skúlason ◽  
Christoph Rose-Petruck ◽  
Hannes Jonsson
Keyword(s):  
Experimental Data ◽  
Electrostatic Interactions ◽  
Computational Cost ◽  
Electrochemical Reactions ◽  
Critical Importance ◽  
Theoretical Estimation ◽  
Implicit Solvation ◽  
Solvation Model ◽  
Implicit Solvation Model ◽  
Constant Potential

Theoretical estimation of the activation energy of electrochemical reactions is of critical importance but remains challenging. In this work, we address the usage of an implicit solvation model for describing hydrogen evolution reaction steps on Pt(111) and Pt(110), and compare with the `extrapolation' approach and co-workers as well as single-crystal measurements. We find that both methods yield qualitatively similar results, which are in fair agreement with the experimental data. Care should be taken, however, in addressing spurious electrostatic interactions between periodically repeated slabs in the VASPsol implementation. Considering the lower computational cost and higher flexibility of the implicit solvation approach, we expect this method to become a valuable tool in electrocatalysis.<br>

scholarly journals Synthesis of DMEA-Grafted Anion Exchange Membrane for Adsorptive Discharge of Methyl Orange from Wastewaters

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 166
Author(s):  
Muhammad Imran Khan ◽  
Abdallah Shanableh ◽  
Javier Fernandez ◽  
Mushtaq Hussain Lashari ◽  
Shabnam Shahida ◽  
...  
Keyword(s):  
Experimental Data ◽  
Methyl Orange ◽  
Ion Exchange ◽  
Anion Exchange ◽  
Freundlich Isotherm ◽  
Exchange Capacity ◽  
Anion Exchange Membrane ◽  
Isotherm Models ◽  
Endothermic Process ◽  
Exchange Membrane

This manuscript describes the synthesis of dimethylethanolamine (DMEA)-grafted anion exchange membrane (AEM) by incorporating dimethylethanolamine as ion-exchange content into the polymer matrix via the solution casting method. The synthesis of the DMEA-grafted AEM was demonstrated by Fourier transform infrared (FTIR) spectroscopy. The prepared DMEA-grafted AEM exhibited higher thermal stability, homogeneous morphology, water uptake (WR) of 115%, and an ion exchange capacity (IEC) of 2.70 meq/g. It was used for the adsorptive removal of methyl orange (MO) from an aqueous solution via batch processing. The effect of several operating factors, including contact time, membrane dosage, initial concentration of aqueous dye solution, and temperature on the percentage discharge of MO and adsorption capacity, was evaluated. Experimental data for adsorption of MO onto the DMEA-grafted AEM was analyzed with two parameter and three parameter nonlinear adsorption isotherm models but fitted best using a nonlinear Freundlich isotherm. Adsorption kinetics were studied by using several models, and attained results showed that experimental data fitted well to pseudo-second-order kinetics. A thermodynamic study showed that adsorption of MO onto the prepared DMEA-grafted AEM was an endothermic process. Moreover, it was a feasible and spontaneous process.

Iodide, caesium and strontium adsorption by organophilic vermiculite

Clay Minerals ◽  
1997 ◽  
Vol 32 (1) ◽  
pp. 21-28 ◽  
Author(s):  
J. Bors ◽  
A. Gorny ◽  
S. Dultz
Keyword(s):  
Experimental Data ◽  
Anion Exchange ◽  
Clay Mineral ◽  
Exchange Process ◽  
Ion Pairs ◽  
Distribution Coefficients ◽  
Chloride Salt ◽  
Original Material ◽  
Considerable Part ◽  
Strontium Ions

AbstractDistribution coefficients and isotherms for the adsorption of radioiodide, caesium and strontium ions (125I−, 134Cs+ and 85Sr2+) were determined in untreated vermiculite and in vermiculite treated with the chloride salt of hexadecylpyridinium (HDPy+). Experimental data reveal that some of the alkylammonium ions were incorporated as HDPyCl ion pairs into the vermiculite. The fraction of ion pairs adsorbed is reflected by an increase in distribution coefficients with increasing saturation levels. Consequently, a considerable part of the iodide adsorption could be attributed to an anion exchange process. At smaller amounts of Cs+ and Sr2+ adsorbed, distribution coefficients of the modified clay mineral are significantly reduced in comparison with the original material. These differences are less pronounced when greater amounts of cations are adsorbed. Generally, larger distribution coefficients were found for the Cs+ compared with the Sr2+ ion in the untreated and modified samples.

scholarly journals Positronium Confined in Nanocavities: The Role of Electron Exchange Correlations

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2350
Author(s):  
Fabrizio Castelli ◽  
Giovanni Consolati ◽  
Giacomo Tanzi Marlotti
Keyword(s):  
Experimental Data ◽  
Electron Density ◽  
General Relation ◽  
Electron Exchange ◽  
Cavity Surface ◽  
Cavity Size ◽  
Cavity Radius ◽  
Geometrical Characteristics ◽  
Reliable Interpretation

Positronium atoms (Ps) are commonly employed as a probe to characterize nanometric or subnanometric voids or vacancies in nonmetallic materials, where Ps can end up confined. The annihilation lifetime of a trapped Ps is strongly modified by pickoff and depends on the cavity size and on the electron density in the confining cavity surface. Here, we develop a theory of the Ps annihilation in nanocavities based on the fundamental role of the exchange correlations between the Ps-electron and the outer electrons, which are not usually considered but must be considered to correctly theorize the pickoff annihilation processes. We obtain an important relation connecting the two relevant annihilation rates (for the p-Psand the o-Ps) with the electron density, which has the property of being totally independent of the geometrical characteristics of the nanoporous medium. This general relation can be used to gather information on the electron density and on the average cavity radius of the confining medium, starting from the experimental data on PALS annihilation spectra. Moreover, by analyzing our results, we also highlight that a reliable interpretation of the PALS spectra can only be obtained if the rule of 1/3 between the intensities of p-Psand o-Pslifetimes can be fulfilled.

Impedance Study of Adsorption of Chloride Ions in Ethanol on Bi(001) Single Crystal Plane

2003 ◽  
Vol 68 (9) ◽  
pp. 1555-1571 ◽  
Author(s):  
Mart Väärtnõu ◽  
Enn Lust
Keyword(s):  
Experimental Data ◽  
Single Crystal ◽  
Electrode Potential ◽  
Chloride Ions ◽  
Crystal Plane ◽  
Potential Range ◽  
Diffusion Resistance ◽  
Ionic Charge ◽  
Electrode Potentials ◽  
Adsorption Capacitance

The impedance spectra for Bi(001) single crystal plane in 0.1, 0.02 and 0.003 M LiCl solutions in ethanol have been measured. It was found that reproducible experimental data for Bi electrode in ethanol solutions could be obtained at ac frequencies between 0.1 and 10 000 Hz and electrode potentials from -1.6 to -0.2 V (vs saturated calomel electrode). Outside this potential region, faradaic processes were detected. By fitting the experimental data to various equivalent circuits it was found that the Frumkin-Melik-Gaikazyan model yields good fit in almost the whole potential range studied. Using this model the dependences of "true" and adsorption capacitance as well as diffusion resistance on electrode potential have been obtained. The ionic charge due to the specific adsorption has been obtained using the mixed-electrolyte method for both electrode charge and electrode potential as the independent electric variables. The Gibbs energy of adsorption of Cl- ions has been calculated using a simple virial adsorption isotherm. It was found that the adsorption of Cl- anion increases in the order methanol < ethanol < propan-2-ol. It was found that on the Bi(001) plane the electrosorption valency has a constant value in the potential range studied. It was concluded that the formed effective surface dipole is significantly screened by the solvent molecules and the metal electron gas.

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