scholarly journals Electrical Conductivity of Natural Volcanic Tuff Mix by Cyclic Voltammetry Method

2021 ◽  
Author(s):  
Ahmad Khalaf Alkhawaldeh
Keyword(s):  
Aqueous Solution ◽  
Electrical Conductivity ◽  
Cyclic Voltammetry ◽  
Electrical Conductance ◽  
Cyclic Voltammograms ◽  
Volcanic Tuff ◽  
High Acid Concentration ◽  
Electronic Conductivities ◽  
Constant State ◽  
Cyclic Voltammetry Method

This paper has experimentally measured volcanic tufa electrical conductance. The calculations are carried out in accordance with the potential of cyclic voltammetry in a constant state. The cyclic voltammograms nanoelectrode platinum prepared electrochemically were examined in the range -0.2 to 1.2 V vs. AgCl [Cl-]:1.0 M in the presence and absence of volcanic tuff in the aqueous solution of 1.0 M HCl. The cyclic voltammetry studies show that the Nano platinum film suffers degradation when the potential exceeds +0.85 V, and below this potential, it is quite stable. The redox reaction of the electrode is reversible. The nanoparticle platinum synthesized at low temperature and high acid concentration exhibits higher electronic conductivities. It has been observed that, relative to area under the peak aggregate tests, the use of volcanic concrete was showing a large increase in electrical conductivity. It was shown that with cyclic voltammetry, three well-defined anode peak could be achieved at a power of 0.0, 0.4 and 0.6 V versus Ag/AgCl.

scholarly journals Electrical Conductivity of Natural Volcanic Tuff Mix by Cyclic Voltammetry Method

2020 ◽  
Author(s):  
Ahmad Khalaf Alkhawaldeh
Keyword(s):  
Aqueous Solution ◽  
Electrical Conductivity ◽  
Cyclic Voltammetry ◽  
Electrical Conductance ◽  
Cyclic Voltammograms ◽  
Volcanic Tuff ◽  
High Acid Concentration ◽  
Electronic Conductivities ◽  
Constant State ◽  
Cyclic Voltammetry Method

This paper has experimentally measured volcanic tufa electrical conductance. The calculations are carried out in accordance with the potential of cyclic voltammetry in a constant state. The cyclic voltammograms nanoelectrode platinum prepared electrochemically were examined in the range -0.2 to 1.2 V vs. AgCl [Cl-]:1.0 M in the presence and absence of volcanic tuff in the aqueous solution of 1.0 M HCl. The cyclic voltammetry studies show that the Nano platinum film suffers degradation when the potential exceeds +0.85 V, and below this potential, it is quite stable. The redox reaction of the electrode is reversible. The nanoparticle platinum synthesized at low temperature and high acid concentration exhibits higher electronic conductivities. It has been observed that, relative to area under the peak aggregate tests, the use of volcanic concrete was showing a large increase in electrical conductivity. It was shown that with cyclic voltammetry, three well-defined anode peak could be achieved at a power of 0.0, 0.4 and 0.6 V versus Ag/AgCl.

CARBON NANOTUBES USED IN ELECTROANALYSIS

2005 ◽  
Vol 19 (01n03) ◽  
pp. 603-605 ◽  
Author(s):  
C. G. HU ◽  
B. FENG
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Cyclic Voltammetry ◽  
Experimental Period ◽  
Cyclic Voltammograms ◽  
Alkaline Aqueous Solution ◽  
Routine Monitoring ◽  
Good Signal ◽  
Better Than

The fabrication of the carboxyl-modified CNT electrode was described. The electroanalytical investigation of sulfadiazine has been conducted in alkaline aqueous solution at the CNT electrode by voltammetry. Highly reproducible and well-defined cyclic voltammograms were obtained for sulfadiazine with a very good signal to background (S/B) ratio. However, no fouling of the electrode was observed at the CNT electrode within the experimental period of several hours, which illustrated that the CNT electrode was much better than traditional electrodes. Meanwhile, the detection of trace sulfadiazine in milk was also conducted by cyclic voltammetry with satisfactory ratio of recovery, indicating that the nanotube electrode can be used in routine monitoring of sulfadiazine residues in food.

Pressure dependences of the electrode potentials of some iron(III/II) and cobalt(III/II) couples in aqueous solution

1992 ◽  
Vol 70 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Hideo Doine ◽  
Todd W. Whitcombe ◽  
Thomas W. Swaddle
Keyword(s):  
Aqueous Solution ◽  
Cyclic Voltammetry ◽  
Ionic Strength ◽  
High Pressures ◽  
Cobalt Complexes ◽  
Cyclic Voltammograms ◽  
Exchange Reactions ◽  
Pressure Limit ◽  
Peak Separation ◽  
Electrode Potentials

The dependences of the electrode potentials E of aqueous Fe(H2O)63+/2+, Fe(phen)33+/2+, Fe(CN)63−/4−, and Co(sep)3+/2+ upon pressure P (up to ca. 200 MPa) have been measured at 25.0 °C relative to an AgCl/Ag(satd. KCl) electrode by cyclic voltammetry. For Co(sep)3+/2+ at ionic strength I = 0.28 and 1.00 mol kg−1, [Formula: see text] is independent of P as well as, giving a volume of reaction ΔV = +13.7 ± 0.4 cm3 mol relative to AgCl/Ag; similarly, for Fe(H2O)63+/2+ at I = 0.28 mol kg−1 (CF3SO3H), ΔV = +5.0 ± 0.3 cm3 mol−1. For Fe(CN)63−/2− in KCl media, [Formula: see text] is independent of P and I at I = 0.28 and 0.51 mol kg−1, giving ΔV = −36.1 ± 1.0 cm3 mol−1, but shows some slight dependence on P at I = 1.00 mol kg−1(low-pressure limit ΔV0 = −38 ± 1 cm3 mol−1; [Formula: see text]. For Fe(phen)33+/2+, [Formula: see text] is markedly pressure and medium dependent, with ΔV0 = +14.2 ± 0.5 and +6.2 ± 0.5 cm3 mol−1 in KNO3 media at I = 0.25 and 1.00 mol kg−1, respectively. The peak-to-peak separation of the cyclic voltammograms increases with increasing P for Fe(CN)63−/4−, but decreases slightly for the cationic couples; these trends can be accounted for in terms of the volumes of activation for the corresponding self-exchange reactions. Keywords: high pressures, electrode potentials, volume of reaction, iron complexes, cobalt complexes.

scholarly journals Behavior and properties of water in silicate melts under deep mantle conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bijaya B. Karki ◽  
Dipta B. Ghosh ◽  
Shun-ichiro Karato
Keyword(s):  
Electrical Conductivity ◽  
Molar Volume ◽  
Water Solution ◽  
Pure Water ◽  
Electrical Conductance ◽  
Water Structure ◽  
Bulk Water ◽  
Silicate Melts ◽  
Pressure Regime ◽  
Low Pressures

AbstractWater (H2O) as one of the most abundant fluids present in Earth plays crucial role in the generation and transport of magmas in the interior. Though hydrous silicate melts have been studied extensively, the experimental data are confined to relatively low pressures and the computational results are still rare. Moreover, these studies imply large differences in the way water influences the physical properties of silicate magmas, such as density and electrical conductivity. Here, we investigate the equation of state, speciation, and transport properties of water dissolved in Mg1−xFexSiO3 and Mg2(1−x)Fe2xSiO4 melts (for x = 0 and 0.25) as well as in its bulk (pure) fluid state over the entire mantle pressure regime at 2000–4000 K using first-principles molecular dynamics. The simulation results allow us to constrain the partial molar volume of the water component in melts along with the molar volume of pure water. The predicted volume of silicate melt + water solution is negative at low pressures and becomes almost zero above 15 GPa. Consequently, the hydrous component tends to lower the melt density to similar extent over much of the mantle pressure regime irrespective of composition. Our results also show that hydrogen diffuses fast in silicate melts and enhances the melt electrical conductivity in a way that differs from electrical conduction in the bulk water. The speciation of the water component varies considerably from the bulk water structure as well. Water is dissolved in melts mostly as hydroxyls at low pressure and as –O–H–O–, –O–H–O–H– and other extended species with increasing pressure. On the other hand, the pure water behaves as a molecular fluid below 15 GPa, gradually becoming a dissociated fluid with further compression. On the basis of modeled density and conductivity results, we suggest that partial melts containing a few percent of water may be gravitationally trapped both above and below the upper mantle-transition region. Moreover, such hydrous melts can give rise to detectable electrical conductance by means of electromagnetic sounding observations.

Cyclohexane oxidation: relationships of the process efficiency with electrical conductance, electronic and cyclic voltammetry spectra of the reaction mixture

2021 ◽  
Vol 132 (1) ◽  
pp. 123-137
Author(s):  
Alexander Pokutsa ◽  
Andriy Zaborovsky ◽  
Pawel Bloniarz ◽  
Tomasz Paczeŝniak ◽  
Dariya Maksym ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Electrical Conductance ◽  
Cyclohexane Oxidation ◽  
Process Efficiency

Polyaniline: Influence of Polymerization Current Density

1994 ◽  
Vol 369 ◽  
Author(s):  
Steen Skaarup ◽  
L.M.W.K. Gunaratne ◽  
Keld West ◽  
Birgit Zachau-Christiansen
Keyword(s):  
Cyclic Voltammetry ◽  
Current Density ◽  
High Current Density ◽  
Electrochemical Polymerization ◽  
Regular Structure ◽  
Spectral Lines ◽  
Complex Nature ◽  
Cyclic Voltammograms ◽  
Layer By Layer ◽  
Current Densities

AbstractPolyaniline has been synthesized in propylene carbonate by galvanostatic electrochemical polymerization at current densities between 16 and 1000 μA/cm2. Earlier results for polypyrrole have shown that low and high current density films have different properties: The films synthesized at low current density have a higher conjugation length and a more regular structure. The corresponding effect in PANI has been investigated by cyclic voltammetry and UV/visible spectroscopy. Simultaneous measurement of cyclic voltammograms and the absorbtion of selected spectral lines is used because of the complex nature of the PANI system which involves several redox systems as well as forms differing in the degree of protonation and morphology.The main result is that the method of galvanostatic synthesis at low current densities (-16 μA/cm2) produces polyaniline polymers of different, more conjugated and more regular structure than those prepared at higher current densities. The standard method of in situ layer-by-layer polymerization of conducting polymers during cyclic voltammetry often results in uncontrolled and unmeasured current densities of 0.5-2 mA/cm2 which produces a film that probably has a less regular structure containing more deviations from ideality.

scholarly journals Impact of external physical effects on water and aqueous solutions: the problem of “memory”

2019 ◽  
Vol 59 (7) ◽  
pp. 1-16
Author(s):  
Ksenia A. Nurislamova ◽  
◽  
Alena S. Franz ◽  
Vyacheslav F. Markov ◽  
Larisa N. Maskaeva ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Electrical Conductivity ◽  
Aqueous Solutions ◽  
Solid Phase ◽  
Cluster Structure ◽  
Lead Salt ◽  
Physical Factors ◽  
Scientific Publications ◽  
Physical Effects ◽  
The Impact

A brief analysis of scientific publications on the changes in the physicochemical properties of water and aqueous solutions under the influence of temperature, magnetic and electric fields, laser and microwave radiation, ultrasound, and mechanical mixing was performed. A number of researchers have shown the influence of such effects on changes in pH and redox potential, electrical conductivity, surface tension and viscosity of an aqueous solution. The question of influence of external physical effects on water and aqueous solutions remains controversial. Some scientists suggest that water has a cluster structure, which is influenced by physical effects. An important aspect of the problem is the impact on the subsequent behavior and the final result of a chemical process involving previously treated aqueous solutions. Using water solutions of lead and thiourea as an example, the effect of their temperature prehistory in the range of 275-369 K on the kinetics of precipitation of the solid phase of lead sulfide and their microstructure is demonstrated. A threefold change in the composition of supersaturated CdxPb1–xS solid solutions precipitated from solutions containing a lead salt with different temperature prehistory was established. It is shown that the “memory” on the preliminary temperature effect is maintained for at least a day. The influence of electromagnetic treatment of water and aqueous solutions on the content of dissolved oxygen, pH and electrical conductivity is analyzed. Some scientists explain these results by the influence of the field on the structure of hydrogen bonds, others by a change in the cluster structure of water, as well as by the presence of ferromagnetic particles in water. The review presents the current state of the problem of the “memory” effect and the related influence of the prehistory of the impact of physical factors. The review suggested that the “memory” of an aqueous solution is the preservation for a certain time of the changes in its structure and properties that have arisen as a result of the effect. The basic ideas about the mechanisms of influence of the prehistory of physical effects on aqueous solutions are given.

scholarly journals NaFePO4 Cathode Prepared from The Caustic Fusion of A Mix Ilmenite-Hematite Followed by Cyclic Voltammetry for Na Insertion

2020 ◽  
Vol 9 (2) ◽  
pp. 142-152
Author(s):  
Fitria Rahmawati ◽  
◽  
Dwi Aman Nur Romadhona ◽  
Syulfi Faiz ◽  
◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Cyclic Voltammetry ◽  
Secondary Phase ◽  
Impedance Analysis ◽  
Fusion Method ◽  
Peak Point ◽  
Fe Content ◽  
Scan Rate ◽  
Hematite Fe2o3 ◽  
Resistance Value

Research to prepare NaFePO4 cathode material from iron sand was conducted. The iron sand consists of ilmenite FeTiO3 and hematite Fe2O3. A caustic fusion method used to precipitate iron as Fe(OH)3 and it increased Fe content up to 94.71 %. Phosphate precipitation successfully produced trigonal FePO4 and monoclinic FePO4 comply with ICSD#412736 and ICSD#281079. The prepared-FePO4 was then used as a precursor for Na insertion by applying cyclic voltammetry mode within 2.0 – 4.0 V with 0.05 mVs-1 of the scan rate. It produced orthorhombic olivine NaFePO4 and a secondary phase of orthorhombic Na0.7FePO4. Impedance analysis at 20 Hz – 5 MHz found that the material provided a semicircle at 100 Hz peak point, indicating electrode-bulk interface with a resistance value of 1735W, comparable to the electrical conductivity of 5.36 x 10-6 Scm-1. Even though the conductivity value is quite lower than NaFePO4 prepared from a commercial FePO4 that has been conducted in our previous research, however the electrical conductivity still reliable for cathode.

scholarly journals Electrochemical synthesis of poly(2-methyl aniline): electrochemical and spectroscopic characterization

2001 ◽  
Vol 66 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Aleksandra Buzarovska ◽  
Irena Arsova ◽  
Ljubomir Arsov
Keyword(s):  
Raman Spectroscopy ◽  
Cyclic Voltammetry ◽  
Redox Reactions ◽  
Electrochemical Polymerization ◽  
Spectroscopic Characterization ◽  
Potential Range ◽  
Cyclic Voltammograms ◽  
Impedance Measurements ◽  
Order Of Magnitude ◽  
Poly Aniline

Poly(2-methyl aniline) or poly(ortho-toluidine), as ring substituted derivative of aniline, has been synthesized electrochemically in various concentrations of H2SO4 and HCl, and then characterized by cyclic voltammetry, as well as by impedance and Raman spectroscopy. The cyclic voltammograms of poly(o-toluidine) and poly(aniline) show that the electrochemical polymerization of these two polymers proceeds by almost identical mechanisms. The Raman spectroscopical measurements suggest that the redox reactions of poly(aniline) and poly(o-toluidine) are similar in the potential range between -0.2 and 0.7V vs. SCE. The impedance measurements showed that the conductivity of poly(o-toluidine) is an order of magnitude lower than that of the corresponding poly(aniline) form.

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