scholarly journals Fe-Mo alloy coatings as cathodes in chlorate production process

2016 ◽  
Vol 70 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Ljiljana Gajic-Krstajic ◽  
Nevenka Elezovic ◽  
Borka Jovic ◽  
Gian Martelli ◽  
Vladimir Jovic ◽  
...  
Keyword(s):  
Mild Steel ◽  
Current Efficiency ◽  
Hydrogen Evolution ◽  
Partial Replacement ◽  
Complete Suppression ◽  
Cathode Reaction ◽  
Mo Catalyst ◽  
Potentiometric Titration Method ◽  
Steel Cathode ◽  
Chlorate Production

The aim of this study was to gain a better understanding of the feasibility of partial replacement of dichromate, Cr(VI), with phosphate buffer, focusing on the cathode reaction selectivity for hydrogen evolution on mild steel and Fe-Mo cathodes in undivided cell for chlorate production. To evaluate the ability of phosphate and Cr(VI) additions to hinder hypochlorite and chlorate reduction, overall current efficiency (CE) measurements in laboratory cell for chlorate production on stationary electrodes were performed. The concentration of hypochlorite was determined by a conventional potentiometric titration method using 0.01 mol dm-3 As2O3 solution as a titrant. The chlorate concentration was determined by excess of 1.0 mol dm-3 As2O3 solution and excess of arsenic oxide was titrated with 0.1 mol dm-3 KBrO3 solution in a strong acidic solution. Cathodic hypochlorite and chlorate reduction were suppressed efficiently by addition of 3 g dm-3 dichromate at both cathodes, except that Fe-Mo cathode exhibited higher catalytic activity for hydrogen evolution reaction (HER). The overvoltage for the HER was around 0.17 V lower on Fe-Mo cathode than on mild steel at the current density of 3 kA m-2. It was found that a dichromate content as low as 0.1 g dm-3 is sufficient for complete suppression of cathodic hypochlorite and chlorate reduction onto Fe-Mo catalyst in phosphate buffering system (3 g dm-3 Na2HPO4 + NaH2PO4). The overall current efficiency was practically the same as in the case of the presence of 3 g dm-3 dichromate buffer (98 %). However, for the mild steel cathode, the overall current efficiency for the chlorate production was somewhat lower in the above mentioned mixed phosphate + dichromate buffering system (95%) than in the pure dichromate buffering solution (97.5%).

scholarly journals Electrodeposition and characterization of Fe–Mo alloys as cathodes for hydrogen evolution in the process of chlorate production

2005 ◽  
Vol 70 (6) ◽  
pp. 879-889 ◽  
Author(s):  
Branimir Grgur ◽  
Nedeljko Krstajic ◽  
Nevenka Elezovic ◽  
Vladimir Jovic
Keyword(s):  
Mild Steel ◽  
Hydrogen Evolution ◽  
Current Density ◽  
Alloy Composition ◽  
Bath Composition ◽  
Alloy Electrodeposition ◽  
Ac Current ◽  
Deposition Conditions ◽  
Chlorate Production

Fe?Mo alloys were electrodeposited from a pyrophosphate bath using a single diode rectified AC current. Their composition and morphology were investigated by SEM, optical microscopy and EDS, in order to determine the influence of the deposition conditions on the morphology and composition of these alloys. It was shown that the electrodeposition parameters, such as chemical bath composition and current density, influenced both the composition of the Fe?Mo alloys and the current efficiency for their deposition, while the micro and macro-morphology did not change significantly with changing conditions of alloy electrodeposition. It was found that the electrodeposited Fe?Mo alloys possessed a 0.15 V to 0.30 V lower overvoltage than mild steel for hydrogen evolution in an electrolyte commonly used in commercial chlorate production, depending on the alloy composition, i.e., the conditions of alloy electrodeposition.

scholarly journals Combining phosphate species and stainless steel cathode to enhance hydrogen evolution in microbial electrolysis cell (MEC)

2010 ◽  
Vol 12 (2) ◽  
pp. 183-186 ◽  
Author(s):  
Leonardo DeSilva Munoz ◽  
Benjamin Erable ◽  
Luc Etcheverry ◽  
Julien Riess ◽  
Régine Basséguy ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Hydrogen Evolution ◽  
Electrolysis Cell ◽  
Microbial Electrolysis Cell ◽  
Stainless Steel Cathode ◽  
Phosphate Species ◽  
Steel Cathode ◽  
Microbial Electrolysis

Cyclizations. Part 3. Use of a mild-steel cathode in the electrochemical intramolecular cyclization of aryl halides

1996 ◽  
Vol 41 (4) ◽  
pp. 489-492 ◽  
Author(s):  
Shileen Donnelly ◽  
James Grimshaw ◽  
Jadwiga Trocha-Grimshaw
Keyword(s):  
Mild Steel ◽  
Intramolecular Cyclization ◽  
Aryl Halides ◽  
Steel Cathode

Application of polarization measurements for current efficiency calculation

2019 ◽  
pp. 32-39
Author(s):  
V. M. Rudoy ◽  
N. I. Ostanin ◽  
T. N. Ostanina ◽  
A. B. Darintseva ◽  
V. S. Nikitin ◽  
...  
Keyword(s):  
Current Efficiency ◽  
Kinetic Parameters ◽  
Hydrogen Evolution ◽  
Current Density ◽  
Hydrogen Reduction ◽  
Background Electrolyte ◽  
Gravimetric Method ◽  
Nickel Sulfate ◽  
Polarization Measurements ◽  
Partial Current

The paper considers a method used to determine Faraday current efficiency (CeF) based on the ratio of partial currents of metal and hydrogen reduction. To calculate the Faraday current efficiency based on polarization measurements, it is necessary to know the working current density and potential (Ei) at which the metal is deposited in the corresponding solution, as well as kinetic parameters of hydrogen evolution for determining the partial current density of hydrogen (iН2 ) at this potential. The proposed method was used to calculate current efficiency for the processes of nickel extraction and nickel coating application from solutions containing nickel sulfate at current density of 300 A/m2. The study allowed to determine kinetic parameters of hydrogen evolution by the polarization curve obtained in the background electrolyte solution containing 120 g/l of magnesium sulfate and 18 g/l of boric acid at pH = 3.9. An equation was obtained to calculate the partial current density of hydrogen evolution at any potential by kinetic parameters. The use of kinetic regularities made it possible to calculate nickel CeF in sulphate solutions of different composition and with different pH values (3.0 and 4.1). The calculated CeF values within the margin of error coincide with the current efficiency value determined by the gravimetric method using a copper coulometer. It is shown that the division of the «total current efficiency» (CeΣ), which is a commercial indicator, into Faraday (CeF) and apparatus (Ceap) indicators in combination with the method using partial polarization provide additional information about the degree of process perfection.

Towards sustainable chlorate production: The effect of permanganate addition on current efficiency

2018 ◽  
Vol 182 ◽  
pp. 529-537 ◽  
Author(s):  
Balázs Endrődi ◽  
Staffan Sandin ◽  
Vera Smulders ◽  
Nina Simic ◽  
Mats Wildlock ◽  
...  
Keyword(s):  
Current Efficiency ◽  
Chlorate Production

scholarly journals Selective Hydrogen Evolution on Manganese Oxide Coated Electrodes: New Cathodes for Sodium Chlorate Production

2019 ◽  
Vol 7 (14) ◽  
pp. 12170-12178 ◽  
Author(s):  
Balázs Endrődi ◽  
Aleksandra Stojanovic ◽  
Maria Cuartero ◽  
Nina Simic ◽  
Mats Wildlock ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
Hydrogen Evolution ◽  
Sodium Chlorate ◽  
Coated Electrodes ◽  
Chlorate Production
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