scholarly journals Zinc Recovery through Electrolytic Refinement Using Insoluble Ir + Sn + Ta + PdOx/Ti Cathode to Reduce Electrical Energy Use

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2779
Author(s):  
Ji-Hyun Kim ◽  
Jung Eun Park ◽  
Eun Sil Lee
Keyword(s):  
Current Density ◽  
Recovery Time ◽  
Hydrogen Generation ◽  
Electrical Energy ◽  
Iron Electrode ◽  
Zinc Recovery ◽  
Recovery Yield ◽  
Electrode Resistance ◽  
Lead Electrode ◽  
A Current

In this study, an alumina (Al) anode, a lead cathode, and insoluble catalytic cathodes (IrOx, PdOx, TaOx, and SnOx) were used as electrodes to enhance zinc recovery. The traditionally used iron electrode and insoluble catalytic electrodes were also used to compare the recovery yield when different types of electrodes were subjected to the same amount of energy. The lead electrode showed over 5000 Ω higher electrode resistance than did the insoluble catalytic electrode, leading to overpotential requiring higher electrical energy. As electrical energy used by the lead and the insoluble catalytic electrodes were 2498.97 and 2262.37 kwh/ton-Zn, respectively, electrical energy can be reduced by 10% when using an insoluble catalytic electrode compared to that when using a lead electrode. Using recovery time (1–4 h) and current density (100–500 A/m2) as variables, the activation, concentration polarization, and electrode resistance were measured for each condition to find the optimum condition for zinc recovery. A recovery yield of about 77% was obtained for up to 3 h of zinc recovery time at a current density of 200 A/m2, which is lower than that (about 80%) obtained at 300 A/m2. After 3 h of recovery time, electrode resistance (Zn concentration reduction, hydrogen generation on electrode surface) and overpotential increase with time decreased at a current density of 200 A/m2, leading to a significant increase in zinc recovery yield (95%).

scholarly journals COD removal from leachate by electrocoagulation process: treatment with monopolar electrodes in parallel connection

2017 ◽  
Vol 77 (1) ◽  
pp. 177-186 ◽  
Author(s):  
Mehtap Tanyol ◽  
Aysenur Ogedey ◽  
Ensar Oguz
Keyword(s):  
Current Density ◽  
Operating Cost ◽  
Oxygen Demand ◽  
Electrical Energy ◽  
Cod Removal ◽  
Iron Electrode ◽  
Time Intervals ◽  
Electrode Distance ◽  
Electrocoagulation Process ◽  
Monopolar Electrodes

Abstract This study examines the removal of chemical oxygen demand (COD) from landfill leachate generated from the municipal landfill site of Bingol, Turkey. The effect of parameters such as current density, pH, and inter-electrode distance during the electrocoagulation (EC) process on COD removal of the process was investigated. Moreover, for COD removal, the energy consumption and operating costs were calculated for iron electrode under the EC conditions. COD removal efficiency was 72.13% at the current density of 16 mA m−2, pH of 8.05, and the inter-electrode distance of 9 mm at the detention time of 60 min with iron electrode and the COD concentration was reduced from 6,100 mg L−1 to 1,700 mg L−1 by EC. The highest value of the electrical energy and electrode consumptions per kg of COD in the optimum conditions were determined as 0.055 kWh kg−1 COD and 3.43 kg kg−1 COD and the highest operating cost value was found to be 1.41 US$ kg−1 COD for 0–60 min time intervals.

scholarly journals Electrosynthesis of Ni-Co/Hydroxyapatite as a Catalyst for Hydrogen Generation via the Hydrolysis of Aqueous Sodium Borohydride (NaBH4) Solutions

2021 ◽  
Vol 15 (3) ◽  
pp. 389-394
Author(s):  
Adrian Nur ◽  
◽  
Anatta W. Budiman ◽  
Arif Jumari ◽  
Nazriati Nazriati ◽  
...  
Keyword(s):  
Current Density ◽  
Hydrogen Generation ◽  
Carbon Anode ◽  
Bipolar Membrane ◽  
Dc Power ◽  
Production Of Hydrogen ◽  
Catalyst Formation ◽  
Hydrolysis Of ◽  
Hydrolysis Of Nabh4 ◽  
A Current

To generate hydrogen from its storage as NaBH4, a catalyst was synthesized via an electrochemical method. The catalyst, Ni-Co, had hydroxyapatite as a support catalyst. The electrochemical cell consisted of a DC power supply, a carbon anode and cathode, and a bipolar membrane to separate the cell into two chambers. The current density was adjusted to 61, 91, and 132 mA/cm2. The electrolysis time was 30, 60, and 90 min. The particles produced were analyzed by XRD and SEM/EDX and tested in the hydrolysis of NaBH4 for hydrogen generation. The Ni-Co/HA catalyst test concluded that the period of time used for electrolysis during catalyst formation was positively correlated with the rate of NaBH4 hydrolysis in the production of hydrogen. The highest rate of hydrogen production was obtained using the synthesized catalyst with a current density of 92 mA/cm2. The NaBH4 hydrolysis reaction followed a first-order reaction with the rate constant of (2.220–14.117)•10-3 l/(g•min). The Arrhenius equation for hydrolysis reactions within the temperature range of 300–323 K is k = 6.5•10-6exp(-6000/T).

scholarly journals Improvement of the membrane-free electrolysis process of hydrogen and oxygen production

2021 ◽  
pp. 117-122
Author(s):  
A. V. Rusanov ◽  
V. V. Solovey ◽  
M. M. Zipunnikov
Keyword(s):  
High Pressure ◽  
Current Density ◽  
Electrical Energy ◽  
Iron Electrode ◽  
Electrochemical Reactions ◽  
Electrolysis Cell ◽  
Half Cycle ◽  
Optimal Range ◽  
Active Mass ◽  
Rational Range

Renewable energy sources provide an unstable energy flow to the units of an autonomous energy complex. Therefore, in order to use the electrolyzer as an element of the considered complex, it is necessary to determine the optimal range of changes in the current density and evaluate the effect of operating characteristics of the electrolysis process on the evolution of H2 (O2) when the electrolyzer power supply is disconnected for 13 seconds against the background of a continuous base current level. Purpose. The main purpose of the research is to determine the rational range of changes in the current density supplied to a monopolar membrane-free high-pressure electrolyzer, as well as to determine the effect of a discrete current supply on electrochemical reactions during electrolysis. Methodology. Comprehensive studies on the electrochemical processes of water decomposition in alkaline electrolyte with the formation of hydrogen and oxygen in an experimental construction make it possible to cyclically supply power to the electrolyzer with visual control of the considered processes. Findings. The technology of cyclic generation of hydrogen and oxygen, which eliminates the need to use separating ion-exchange membranes, is considered. A rational range of changes in the current density on a membrane-free monopolar high-pressure electrolyzer with the usage of electrodes made of metals with variable valence is established. The influence of the discrete supply of electrical energy to the electrolysis cell is determined depending on the electrochemical reactions occurring on the active iron electrode. Theoretical values of the voltage of the oxidation and reduction of the iron electrode active mass, as well as the voltage on the half-cycle of hydrogen evolution during the electrolysis of water, are calculated. Originality. An increase in the blackout time from 1 to 3 s leads to a corresponding increase in time of the oxidation process on the hydrogen half-cycle by a factor of 2.4. In addition, the total amount of hydrogen (oxygen) released during the corresponding half-cycles remains unchanged and amounts to Practical value. The optimal range of current density for the operation of a membrane-free high-pressure electrolyzer is in the range of 200400 A/m2. Under such conditions, an intense redox process of the iron electrode active mass occurs. Electrical energy consumption in this case is in the range of 3.94.1 kW h/m3. An experimental study on the electrolyzer discrete power supply effect on its ability to generate gas is carried out. This makes it possible to supply electrical energy to the electrolysis cell directly from the primary energy source (sun, wind) as part of the energy technology complex.

scholarly journals Etude des paramètres opératoires d’électrocoagulation pour le traitement d’un effluent de textile : Exemple du bleu de méthylène

2021 ◽  
Vol 15 (2) ◽  
pp. 790-802
Author(s):  
Yibor Fabrice Roland Bako ◽  
Inoussa Zongo ◽  
Yssouf Karanga ◽  
Issa Tapsoba ◽  
Issoufou Sawadogo ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Current Density ◽  
Advanced Oxidation Processes ◽  
Industrial Effluents ◽  
Iron Electrode ◽  
Textile Dye ◽  
Physical Processes ◽  
Bleu De Méthylène ◽  
Iron Aluminum ◽  
A Current

Les effluents industriels issus des activités textiles présentent une grande charge polluante difficilement biodégradable et qui a des impacts non négligeables sur l’environnement et l’Homme. Leur décontamination par les procédés conventionnels biologiques ou physiques est souvent inefficace et nécessite par conséquent le recours à des procédés d’oxydation avancée dont l’électrocoagulation. Dans le présent travail, nous avons étudié l’élimination par électrocoagulation du bleu de méthylène, modèle de colorant synthétique textile, en utilisant des électrodes de fer et d’aluminium. L’étude des paramètres pouvant influencer l’élimination par électrocoagulation du bleu de méthylène tels que le pH, la durée de l’électrolyse, la densité de courant et la nature de l’anode a montré que les meilleurs traitements sont obtenus avec un effluent de pH égal à 7 pendant 4 heures d’électrolyse à une densité de courant de 3,75 A/cm2 en utilisant l’électrode de fer. Dans ces conditions, le pourcentage d’élimination du bleu de méthylène dans les eaux atteint 80,1%. Des électrodes en fer seraient donc plus intéressantes pour l’élimination du bleu de méthylène, comparativement à des électrodes en aluminium.Mots clés : Electrocoagulation, fer, aluminium, effluents industriels, bleu de méthylène.   English Title: Study of operator parameters in electrocoagulation for the treatment of a synthetic textile effluent: example of methylene blueIndustrial effluents from textile activities have a large polluting load that is difficult to biodegrade and which has significant impacts on the environment and on humans. Their decontamination by conventional biological or physical processes is often ineffective and therefore requires the use of advanced oxidation processes including electrocoagulation. In the present work, we investigated the  electrocoagulation removal of methylene blue, a synthetic textile dye model, using iron and aluminum electrodes. The study of the parameters of EC which can influence the elimination of methylene blue in wastewater, such as the pH, the duration of the electrolysis, the  current density and the nature of the anode showed that the best treatment are obtained with a pH effluent equal to 7, for 4 hours of electrolysis with an iron electrode at a current density of 3.75 A / cm2. Under these conditions, the percentage of elimination of methylene blue in water reaches 80.1%. Iron electrodes would therefore be more advantageous for the removal of methylene blue, compared to aluminum electrodes.Keywords: Electrocoagulation, iron, aluminum, industrial effluents, methylene blue.

scholarly journals Different Electrodes Connections in Electrocoagulation of Synthetic Blow down Water of Cooling Tower

2020 ◽  
Vol 21 (1) ◽  
pp. 1-7
Author(s):  
Enas Ali Anwer ◽  
Basma A. Abdul Majeed
Keyword(s):  
Current Density ◽  
Cooling Tower ◽  
Electrical Energy ◽  
Operating Conditions ◽  
Blow Down ◽  
Dissolved Silica ◽  
Parallel Arrangement ◽  
Initial Ph ◽  
Calcium Magnesium ◽  
A Current

In this research, the performance of electrocoagulation (EC) using aluminum (Al) electrodes with   Monopolar- parallel (MP-P), and bipolar - series (BP-S) arrangement for simultaneous removal of dissolved silica, and hardness ions (calcium, and magnesium) from synthetic blowdown water of cooling tower were investigated. The effects of current density, initial pH and time of electrolysis on the removal efficiency were studied in a batch stirred unit to find out the best-operating conditions. The obtained results for each target species are evidence that BP-S approach is the best for both electrodes configuration operated at a Current density of 1mA/cm2 through 30 min of treatment and pH=10 with the removal of 60 %, 97% and 98% for calcium, magnesium and silica, respectively. This arrangement required an electrical energy consumption of1.8 kWh/m3 which is higher than observed in a parallel arrangement.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

A highly stable CoMo2S4/Ni3S2 heterojunction electrocatalyst for efficient hydrogen evolution

2021 ◽  
Author(s):  
Minmin Wang ◽  
Mengke Zhang ◽  
Wenwu Song ◽  
Weiting Zhong ◽  
Xunyue Wang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Current Density ◽  
A Current

A CoMo2S4/Ni3S2 heterojunction is prepared with an overpotential of only 51 mV to drive a current density of 10 mA cm−2 in 1 M KOH solution and ∼100% of the potential remains in the ∼50 h chronopotentiometric curve at 10 mA cm−2.

Real-Time Tem Studies of Electromigration in Submicron Aluminum Runners

1995 ◽  
Vol 391 ◽  
Author(s):  
S. P. Riege ◽  
A. W. Hunt ◽  
J. A. Prybyla
Keyword(s):  
Real Time ◽  
Joule Heating ◽  
Current Density ◽  
Constant Voltage ◽  
Sample Design ◽  
A Current

AbstractDirect real-time observations of electromigration (EM) in submicron Al interconnects were made using a special sample-stage which allowed TEM observations to be recorded while simultaneously heating and passing current through the sample. The samples consisted of 4000 Å thick Al(0.5wt%Cu) patterned over a TEM-transparent window into five runners in parallel, with linewidths 0.2, 0.3, 0.5, 0.8, and 1.0 μm. Both passivated and unpassivated samples were examined. A current density of 2 x 106A/cm2 was used with temperatures ranging from 200 - 350°C. The experiments were done using constant voltage testing, and we used a special sample design which dramatically minimized Joule-heating. Our approach has allowed us to directly observe voids form, grow, migrate, pin, fail a runner, and heal, all with respect to the detailed local microstructure of the runners.

scholarly journals Impact of Process Parameters on the Diameter of Nanobubbles Generated by Electrolysis on Platinum-Coated Titanium Electrodes Using Box–Behnken Experimental Design

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2542
Author(s):  
Karol Ulatowski ◽  
Radosław Jeżak ◽  
Paweł Sobieszuk
Keyword(s):  
Experimental Design ◽  
Process Parameters ◽  
Current Density ◽  
Salt Concentration ◽  
Multivariate Regression ◽  
Electrical Energy ◽  
Multiphase System ◽  
Anova Analysis ◽  
Dependent Variables ◽  
Parameter Function

(1) The generation of nanobubbles by electrolysis is an interesting method of using electrical energy to form bubble nuclei, effectively creating a multiphase system. For every process, the effectiveness of nanobubble generation by electrolysis depends on various process parameters that impact should be determined. (2) In this work, the electrolytic generation of hydrogen and oxygen bubbles was performed in a self-built setup, in which a Nafion membrane separated two chambers. The generation of bubbles of both gases was investigated using Box–Behnken experimental design. Three independent variables were salt concentration, current density, and electrolysis time, while the dependent variables were Sauter diameters of generated bubbles. An ANOVA analysis and multivariate regression were carried out to propose a statistical and power model of nanobubble size as a process parameter function. (3) The generation of bubbles of hydrogen and oxygen by electrolysis showed that different factors or their combinations determine their size. The results presented in this work proved to be complementary to previous works reported in the literature. (4) The Sauter diameter of bubbles increases with salt concentration and stays constant with increasing current density in investigated range. The proposed correlations allow the Sauter diameters of nanobubbles generated during electrolysis to be predicted.

Sign in / Sign up

Export Citation Format

Share Document