Showing papers on "Supporting electrolyte published in 2009"
TL;DR: In this paper, a single-metal redox flow battery employing chromium(III) acetylacetonate in tetraethylammonium tetrafluoroborate and acetonitrile has been investigated using electrochemical techniques.
287 citations
TL;DR: Compared to the various other adsorbents reported in the literature, the walnut hull in this study shows very good promise for practical applicability and may be a chemically controlled process.
193 citations
TL;DR: Nitrate could be completely removed by the simultaneous reduction and oxidation developed in this study, which is suitable for deep treatment of nitrate polluted water.
189 citations
TL;DR: A comparison between the model results and experimental data gave high correlation coefficient shows that the model is able to predict the concentration of residual Cr(VI) in the solution, which was more effective than Na(2)SO(4) and NaNO(3) in removal of hexavalent chromium.
175 citations
TL;DR: In this article, a cyclic voltammetry at a hemispherical electrode under conditions where the electric field is nonzero and migration is significant to mass transport is presented, where the nonlinear set of differential equations formed by combining the Nernst−Planck equation and the Poisson equation are solved numerically, subject to a zero-field approximation at the electrode surface.
Abstract: Theory is presented for cyclic voltammetry at a hemispherical electrode under conditions where the electric field is nonzero and migration is significant to mass transport. The nonlinear set of differential equations formed by combining the Nernst−Planck equation and the Poisson equation are solved numerically, subject to a zero-field approximation at the electrode surface. The effects on the observed voltammetry of the electrode size, scan rate, diffusion coefficient of electroactive and supporting species, and quantity of supporting electrolyte are noted. Comparison is drawn with experimental voltammetry for the aqueous system [Ru(NH3)6]3+/2+ at a Pt macroelectrode with varying levels of supporting electrolyte KCl. The approximations concerned are shown to be applicable where the ratio of supporting (background) electrolyte to bulk concentration of electroactive species (support ratio) exceeds 30, and general advice is given concerning the quantity of supporting electrolyte required for quantitatively d...
148 citations
TL;DR: Electrocoagulation showed that with increasing applied potential and electrolysis time, the Al(3+) dosage increases, and thereby favouring the fluoride ions removal, and it was observed that defluoridation is dependant on the concentration of supporting electrolyte.
147 citations
TL;DR: The chemical oxidation of H(2)TFcP was tested using a variety of oxidants which resulted in formation of mixed-valence compounds, which were characterized by UV-vis-NIR, MCD, IR, Mossbauer, and XPS spectroscopy.
Abstract: Redox properties of H2TFcP [TFcP2− = 5,10,15,20-tetraferrocenylporphyrin(2−)] were investigated using cyclic voltammetry, differential pulse voltammetry, and square-wave voltammetry methods in a large variety of solvents and electrolytes. When DMF, THF, and MeCN were used with TBAP as the supporting electrolyte, the first oxidation wave was assigned to a single four-electron oxidation process reflecting simultaneous oxidation of all iron(II) centers into iron(III) centers in H2TFcP. When an o-DCB (1,2-dichlorobenzene)/TBAP combination was used in electrochemical experiments, four ferrocene substituents underwent two very diffuse, “two-electron” stepwise oxidations. The use of a weakly coordinating TFAB ([NBu4][B(C6F5)4]) electrolyte in o-DCB or DCM results in four single-electron oxidation processes for ferrocene substituents in which the first and second single-electron waves have a relatively large separation, while the second, third, and fourth oxidation processes are more closely spaced; similar resul...
140 citations
TL;DR: It is demonstrated that a 50 nm high solution-filled cavity bounded by two parallel electrodes in which electrochemically active molecules undergo rapid redox cycling can be used to determine very fast electron-transfer kinetics.
Abstract: We demonstrate that a 50 nm high solution-filled cavity bounded by two parallel electrodes in which electrochemically active molecules undergo rapid redox cycling can be used to determine very fast electron-transfer kinetics. We illustrate this capability by showing that the heterogeneous rate constant of Fc(MeOH)2 sensitively depends on the type and concentration of the supporting electrolyte. These solid-state devices are mechanically robust and stable over time and therefore have the potential to become a widespread and versatile tool for electrochemical measurements.
125 citations
TL;DR: In this paper, the authors studied the kinetics and reaction mechanism of nitrate reduction on a copper electrode in 0.1 M NaOH, which acts as the supporting electrolyte.
125 citations
TL;DR: In this paper, the effects of influential variables governing the efficiency of the process such as initial dye concentration, pH, current density, and electrolyte concentration were studied, and the decrease of absorbance at UV region in UV-Vis spectra was indicative of the aromatic ring degradation.
122 citations
TL;DR: In this paper, the authors investigated the electrochemical oxidation of glyphosate herbicide (GH) on RuO 2 and IrO 2 dimensionally stable anode (DSA ® ) electrodes.
TL;DR: The dependence of the oxidation potential of ferrocene on the electrolyte concentration for differentsolvents revealed that the abovementioned approximation in the Born correction term indeed introduces a significant error in the estimation of the charge-transfer driving force from redox data collected using relatively nonpolar solvents.
Abstract: The estimation of the driving force for photoinduced charge-transfer processes, using the Rehm-Weller equation, requires the employment of redox and spectroscopic quantities describing the participating electron donor and acceptor. Although the spectroscopic data are usually obtained from diluted solutions, the redox potentials are most frequently obtained from electrochemical measurements conducted in concentrated electrolyte solutions. To correct for the differences in the media, in which the various types of measurements are conducted, a term, based on the Born equation for solvation energy of ions, is introduced in the Rehm-Weller equation. The Born correction term, however, requires a prior knowledge of the dielectric constants of the electrolyte solutions used for the redox measurements. Because of limited information for such dielectrics, the values for the dielectric constants of electrolyte solutions are approximated to the values of the dielectric constants of the corresponding neat solvents. We examined the validity of this approximation. Using cyclic voltammetry, we recorded the first one-electron oxidation potential of ferrocene for three different solvents in the presence of 1-500 mM supporting electrolyte. The dielectric constants for some of the electrolyte solutions were extracted from fluorescence measurements of a dimethylaminonaphthalimide chromophore that exhibits pronounced solvatochromism. The dielectric constants of the concentrated electrolyte solutions correlated well with the corresponding oxidation potentials. The dependence of the oxidation potential of ferrocene on the electrolyte concentration for different solvents revealed that the abovementioned approximation in the Born correction term indeed introduces a significant error in the estimation of the charge-transfer driving force from redox data collected using relatively nonpolar solvents.
TL;DR: In this article, the electrochemical oxidation of acid black 210 dye (AB-210) on the boron-doped diamond (BDD) was investigated under different pH conditions.
TL;DR: In this article, the influence of electrolysis time, applied charge density, electrolyte pH and supporting electrolyte on electro-coagulation efficiency for the treatment of pulp and paper industrial effluent has been attempted in the present investigation.
TL;DR: Electrochemical investigations on devices based on PEDOT-MWCNT and control P EDOT films established the practical utility of PEDot-MWcNT films as they show lower charge-transfer resistance, higher diffusional capacitance, and a much smaller amplitude of impedance as compared to control PED OT films.
Abstract: Composite thin films of poly(3,4-ethylenedioxythiophene) (PEDOT)-enwrapped functionalized multiwalled carbon nanotubes (MWCNTs) have been synthesized over multiple length scales by electropolymerization of the monomer without the use of any other supporting electrolyte. The functionalized MWCNTs are incorporated into the positively charged polymer deposit as counterions during oxidative electropolymerization. The morphology, electrochemistry, and electrochromism of the PEDOT−MWCNT films have been compared with those of control PEDOT films doped by triflate ions. Such a comparison enabled us to demonstrate the profound effect of MWCNTs as counterions, realized in terms of better electropolymerization rate, higher conductivity, faster color−bleach kinetics, higher charge storage capacity, and substantially amplified coloration efficiency (η = 414 cm2 C−1, λmax = 575 nm, E = −1.5 V) in comparison to the values of η reported to date for PEDOT. The strong interaction between the polymer and MWCNTs, the interco...
TL;DR: It was found that the potential separation between the first and second processes was especially sensitive to water in the low molar levels (0.001-0.1 M); therefore, by measuring the peak separation as a function of controlled water concentrations it was possible to prepare calibration curves of peak separation versus water concentration.
Abstract: Vitamin K1 (VK1) was shown by voltammetry and coulometry to undergo two chemically reversible one-electron reduction processes in acetonitrile (CH3CN) containing 0.2 M Bu4NPF6 as the supporting electrolyte. The potential separation between the first and second electron-transfer steps diminished sequentially with the addition of water, so that at a H2O concentration of approximately 7 M (∼13% v/v) only one process was detected, corresponding to the reversible transfer of two electrons per molecule. The voltammetric behavior was interpreted on the basis of the degree of hydrogen bonding between the reduced forms of VK1 with water in the solvent. It was found that the potential separation between the first and second processes was especially sensitive to water in the low molar levels (0.001−0.1 M); therefore, by measuring the peak separation as a function of controlled water concentrations (accurately determined by Karl Fischer coulometric titrations) it was possible to prepare calibration curves of peak sep...
TL;DR: The electrochemical behaviors of tryptophan at the modified GCE was found to be greatly improved compared with that at the bare GCE, and the proposed method was sensitive and simple and was successfully employed to determine tryptophile in pharmaceutical samples.
TL;DR: Results for the indium ion removal kinetics at various current densities show that the kinetic rates conformed to the pseudo-second-order kinetic model with good correlation.
TL;DR: A wide dynamic working range of 0-850mg/L can be achieved by this method, much wider than any other photoeletrocatalytic methods using TiO(2) nanoparticles or nanofilms in the reported literature.
TL;DR: Electrochemical oxidation using Ti/RuO(2) could be efficiently used to reduce more than 90% of the COS toxicity and under optimal conditions, 84% of petroleum hydrocarbon was removed and high performance of PAH degradation could be recorded without initial pH adjustment.
TL;DR: Results from the indium (III) ion removal kinetics show that the kinetics data fit the pseudo second-order kinetic model well and indicate that a Fe/Al electrode pair is the most efficient choice of the four electrode pairs in terms of energy consumption.
TL;DR: In this paper, the performance of the SDS-POAP carbon paste electrode has been investigated by cyclic voltammetry in 0.5m HClO4 and 5mM K4[Fe(CN)6]/0.1m NaOH solution.
TL;DR: In this article, the effect of current density, supporting electrolyte concentration, electrolysis duration, specific electrode surface and fluid flow rate on pollutant removal and energy consumption was critically evaluated.
Abstract: This study focused on the electrochemical degradation of hydrolyzed Remazol Black
B (CI Reactive Black 5), a common diazo reactive dye, in aqueous solution. In the presence
of various auxiliary dye chemicals, a typical Remazol Black simulated exhausted
dyebath liquor was treated electrochemically in various basic electrochemical reactor
configurations such as batch, batch recirculation and single pass systems. The effect of current density, supporting electrolyte concentration, electrolysis duration, specific
electrode surface and fluid flow rate on pollutant removal and energy consumption
performance of the systems was critically evaluated. Batch studies show the following
operating parameters, current density: 2.5 A/dm2, electrolysis duration: 6 h,
and supporting electrolyte concentration: 3 g/L, were optimal for good overall performance
of the system. Color removal was complete by 3 h of treatment for all combinations
of parameters studied. The pollutant removal performance of the batch
recirculation system was found to have improved considerably by increasing the flow
rate. Performance of the batch recirculation system was comparatively better than
the other rector configurations studied, with respect to capacity utilization and
energy consumption.
TL;DR: It is found that chaotropic anions lead to larger thickness increments per bilayer during the film buildup than cosmotropic ones, confirming results found on PSS/PDADMA multilayers, and that a film constructed in the presence of chaotropicAnions swells and becomes more permeable to Fe(CN)(6)4- ions when the film is brought into contact with a solution containing more cosMotropic anions.
Abstract: Quartz crystal microbalance and cyclic voltammetry are used to investigate the influence of the supporting salt of polyelectrolyte solutions on the buildup and the structure of PSS/PAH polyelectrolyte multilayers (PSS: poly(4-styrene sulfonate); PAH: poly(allylamine hydrochloride)). This film constitutes a model polyelectrolyte multilayer system. The supporting electrolytes were sodium salts where the nature of the anion was changed by following the Hofmeister series from cosmotropic to chaotropic anions (F−, Cl−, NO3−, ClO4−). For all the investigated anions, the film thickness increases linearly with the number of deposition steps. We find that chaotropic anions lead to larger thickness increments per bilayer during the film buildup than cosmotropic ones, confirming results found on PSS/PDADMA multilayers (PDADMA: poly(diallyldimethylammonium)). Films constituted by more than nine PSS/PAH bilayers are still permeable to hexacyanoferrate(II) ions, Fe(CN)64−, whatever the nature of the supporting salt ani...
TL;DR: In this article, a carbon ionic liquid electrode (HAP-CILE) was developed for the simultaneous determination of lead and cadmium using square wave anodic stripping voltammetry (SWASV).
Abstract: In this paper, a hydroxyapatite-modified carbon ionic liquid electrode (HAP-CILE) for the simultaneous determination of lead and cadmium was developed. The hydroxyapatite which combines with ionic liquid plays an important role in remarkable responses of metals. Trace analysis of the selected heavy metals was performed by square-wave anodic stripping voltammetry (SWASV). The oxidation of two metals yielded well-defined, separated square-wave peak currents. The peak currents at about −0.34 V for Pb 2+ and −0.88 V for Cd 2+ were measured. The affecting factors containing supporting electrolyte, pH of solution, accumulation time, deposition potential, amount of hydroxyapatite and possible interferences were investigated. The sensor exhibited linear behavior in the range of 1 × 10 −9 mol L −1 to 1 × 10 −7 mol L −1 for lead and cadmium (correlation coefficients: 0.995 and 0.997, respectively) with detection limits of 2 × 10 −10 mol L −1 for lead and 5 × 10 −10 mol L −1 for cadmium. The results indicate that the sensor is sensitive and effective for the simultaneous determination of lead and cadmium.
TL;DR: Under the optimum conditions, COD and turbidity decreased by more than 90% and 98% in real oxide-CMP wastewater, respectively.
TL;DR: In this article, the anodic electrochemistry of nickelocene has been examined in 12 different nonaqueous solvents or solvent mixtures using [NBu4][TFAB] (TFAB=[B(C6F5)4]−) as the supporting electrolyte.
TL;DR: A simple, environmentally friendly and continuous flow method was developed for the determination of COD based on a flow injection analysis (FIA) system, in which a BDD electrode was employed as the detecting element and the COD values determined compared well with those analyzed by the conventional method.
Abstract: A simple, environmentally friendly and continuous flow method was developed for the determination of COD based on a flow injection analysis (FIA) system, in which a BDD electrode was employed as the detecting element. The structure and the electrochemical behavior of BDD were investigated by a scanning electron microscope, Raman spectroscopy, and cyclic voltammetry, respectively. The results demonstrated that the high-quality BDD film prepared here was suitable to be used as an electrode, with which the COD measurement could be conducted. The effect of several important experimental parameters, such as applied potentials, pH, flow rates, and supporting electrolyte concentrations, on the analytical performance was investigated. Under optimized testing conditions, the proposed method was successfully applied in the COD analysis of synthetic samples. The linear range and the detection limit were 2−175 and 1 mg L−1, respectively. In addition, the COD values determined by the proposed method compared well with...
TL;DR: The good fit of the data to pseudo-first-order kinetics for COD removal at all applied voltages was taken as proof of the involvement of indirect oxidation pathways in the process.
TL;DR: In this paper, a detailed study on the electrochemical oxidation of aqueous solutions of Remazol Brilliant Blue Reactive on a boron-doped diamond electrode is presented.