scholarly journals Electric conversion treatment of cobalt-containing wastewater

2021 ◽  
Author(s):  
Shengnan Lin ◽  
Xijuan Pan ◽  
Deliang Meng ◽  
Tingan Zhang
Keyword(s):  
Current Density ◽  
Cobalt Hydroxide ◽  
Single Factor ◽  
Cobalt Ions ◽  
Initial Concentration ◽  
Comprehensive Utilization ◽  
Valuable Metals ◽  
Pollute Groundwater ◽  
Electrolysis Product

Abstract Long-term accumulation of cobalt-containing wastewater may also pollute groundwater and cause a large amount of loss of valuable metals. Therefore, the comprehensive utilization of cobalt-containing wastewater must be realized, especially cobalt itself is a very important strategic resource. This paper proposes a membrane electroconversion method to separate cobalt ions from cobalt-containing wastewater and prepare cobalt hydroxide. In addition, the electrolysis process was optimized, and single-factor experiments such as the initial concentration, cobalt ions, current density, temperature et al., and economic calculations such as current efficiency were explored. And the electrolysis product was calcined as the precursor to obtain the oxide Co3O4, and the calcining experiment was also optimized. In this concentration range, more than 90% of cobalt can be recovered within 2 h.

Applicability of electrodialysis to the separation of sodium acetate from synthetic alkaline hardwood extract

TAPPI Journal ◽  
2015 ◽  
Vol 14 (11) ◽  
pp. 695-708 ◽  
Author(s):  
RAVIKANT PATIL ◽  
CHI TRUONG ◽  
JOSEPH GENCO ◽  
HEMANT PENDSE ◽  
ADRIAAN VAN HEININGEN
Keyword(s):  
Current Density ◽  
Sodium Sulfate ◽  
Sodium Acetate ◽  
Separation Efficiency ◽  
Feed Concentration ◽  
Initial Concentration ◽  
White Liquor ◽  
Complete Extraction ◽  
Electro Osmosis ◽  
Preliminary Separation

Our objective was to develop a process for recovering acetyl groups from industrial northeast hardwood chips. Extraction experiments showed that the white liquor charge of 6% effective alkali at 50°C and liquor-to-wood ratio of 4:1 leads to the complete extraction of acetyl groups from industrial hardwood chips. Electrodialysis was assessed as a technique for separating and concentrating sodium acetate from synthetic hardwood extract. Preliminary separation experiments using dilute sodium acetate showed that the sodium acetate can be concentrated up to approximately 24% by weight from an initial concentration of about 2% by weight. The effects of current density, feed concentration, electro-osmosis, and osmosis on the separation of sodium acetate were evaluated. Finally, selectivity experiments were performed to study the effect of various components of the white liquor on the separation of sodium acetate. Fully oxidized synthetic white liquor was used in selectivity experiments to avoid deleterious effects of Na2S. Selectivity experiments using synthetic oxidized white liquor showed a significant decrease in the separation efficiency due to the presence of sodium hydroxide, sodium carbonate, and sodium sulfate in the synthetic extract.

scholarly journals Nanoporous Activated Carbon Derived from Rice Husk for High Performance Supercapacitor

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Huaxing Xu ◽  
Biao Gao ◽  
Hao Cao ◽  
Xueyang Chen ◽  
Ling Yu ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Specific Capacitance ◽  
Current Density ◽  
Average Pore Size ◽  
Nanoporous Carbon ◽  
Cycle Life ◽  
Potential Candidate ◽  
Average Pore ◽  
Nanoporous Activated Carbon

Nanoporous activated carbon material was produced from the waste rice husks (RHs) by precarbonizing RHs and activating with KOH. The morphology, structure, and specific surface area were investigated. The nanoporous carbon has the average pore size of 2.2 nm and high specific area of 2523.4 m2 g−1. The specific capacitance of the nanoporous carbon is calculated to be 250 F g−1at the current density of 1 A g−1and remains 80% for 198 F g−1at the current density of 20 A g−1. The nanoporous carbon electrode exhibits long-term cycle life and could keep stable capacitance till 10,000 cycles. The consistently high specific capacitance, rate capacity, and long-term cycle life ability makes it a potential candidate as electrode material for supercapacitor.

scholarly journals Copper and Lead Ions Removal by Electrocoagulation: Process Performance and Implications for Energy Consumption

2021 ◽  
Vol 10 (3) ◽  
pp. 415-424
Author(s):  
Aji Prasetyaningrum ◽  
Dessy Ariyanti ◽  
Widayat Widayat ◽  
Bakti Jos
Keyword(s):  
Heavy Metals ◽  
Energy Consumption ◽  
Removal Efficiency ◽  
Current Density ◽  
High Current Density ◽  
Energy Requirement ◽  
Lead Ions ◽  
Initial Concentration ◽  
Electroplating Wastewater ◽  
Electrocoagulation Process

Electroplating wastewater contains high amount of heavy metals that can cause serious problems to humans and the environment. Therefore, it is necessary to remove heavy metals from electroplating wastewater. The aim of this research was to examine the electrocoagulation (EC) process for removing the copper (Cu) and lead (Pb) ions from wastewater using aluminum electrodes. It also analyzes the removal efficiency and energy requirement rate of the EC method for heavy metals removal from wastewater. Regarding this matter, the operational parameters of the EC process were varied, including time (20−40 min), current density (40−80 A/m2), pH (3−11), and initial concentration of heavy metals. The concentration of heavy metals ions was analyzed using the atomic absorption spectroscopy (AAS) method. The results showed that the concentration of lead and copper ions decreased with the increase in EC time. The current density was observed as a notable parameter. High current density has an effect on increasing energy consumption. On the other hand, the performance of the electrocoagulation process decreased at low pH. The higher initial concentration of heavy metals resulted in higher removal efficiency than the lower concentration. The removal efficiency of copper and lead ions was 89.88% and 98.76%, respectively, at 40 min with electrocoagulation treatment of 80 A/m2 current density and pH 9. At this condition, the specific amounts of dissolved electrodes were 0.2201 kg/m3, and the energy consumption was 21.6 kWh/m3. The kinetic study showed that the removal of the ions follows the first-order model.

scholarly journals Sediment Mining

2017 ◽  
Author(s):  
Homayoun Fathollahzadeh ◽  
Fabio Kaczala ◽  
Amit Bhatnagar ◽  
William Hogland
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Contaminated Sediments ◽  
Management Options ◽  
Metals Recovery ◽  
Environmental Footprints ◽  
Valuable Metals ◽  
Short And Long Term ◽  
Near Future

The main dilemma of contaminated sediments has been the proper management with reduced environmental footprints. Furthermore, by considering the fact that global warming and climate change may complicate the choice of management options, finding appropriate solutions become extremely critical. In the present work, mining of contaminated sediments to recover valuable constituents such as metals and nutrients is proposed as sustainable strategy, both through enhancing resilience of ecosystem and remediation. Contaminated sediments in the Oskarshamn harbor, southeast of Sweden were collected and analyzed through a modified sequential extraction in order to evaluate the feasibility of metals recovery. The results have shown that among different metals present in the sediments, Cu and Pb can be initially considered as economically feasible to recover. The shifting in the concept of dredging and further remediation of contaminated sediments towards sediment mining and recover of valuable metals can be considered in the near future as a sustainable strategy to tackle contaminated harbor/ports areas. However, it must be highlighted that short and long-term environmental impacts related to such activities should be addressed.

Synthesis of Samarium Cobalt Oxide Nanosheets and Nanoflowers on Nickel Foam via Electrochemical Route

2021 ◽  
Vol 1047 ◽  
pp. 85-89
Author(s):  
Lance Patrick M. Buizon ◽  
Menandro C. Marquez
Keyword(s):  
Electron Microscopy ◽  
Cobalt Oxide ◽  
Electrochemical Sensors ◽  
Nickel Foam ◽  
Electrochemical Energy Storage ◽  
Cobalt Hydroxide ◽  
Energy Storage Devices ◽  
Cobalt Ions ◽  
Storage Devices ◽  
Scanning Electron

Cobalt oxide (Co3O4) nanosheets were successfully synthesized and deposited onto the nickel foam substrate via electrochemical route. The chronoamperograms during the deposition revealed electrochemical activity resulting to the nucleation of the cobalt ions forming cobalt hydroxide and transformation to cobalt oxide. Energy dispersive xray (EDX) results elucidates the presence of samarium, cobalt and oxygen in the sample. The formation of nanosheets was confirmed by scanning electron microscopy. It was found that adding more samarium in the electrochemical bath changes the morphology of the final product from nanosheets to nanoflowers. The evolution of nanosheets to nanoflowers of the synthesized material could pave way for its potential application in the field of electrochemical energy storage devices and electrochemical sensors.

Electrochemical Oxidation of Azo Dye Wastewater Using Graphene-Based Electrode Materials

2019 ◽  
Vol 19 (11) ◽  
pp. 7308-7314
Author(s):  
Jinyan Li ◽  
Qingsong Guan ◽  
Junming Hong ◽  
Chang-Tang Chang
Keyword(s):  
Electrochemical Oxidation ◽  
Current Density ◽  
Electrode Materials ◽  
Supporting Electrolyte ◽  
Performance Comparison ◽  
Carbon Cloth ◽  
Reactive Black 5 ◽  
Dye Wastewater ◽  
Composite Electrodes ◽  
Initial Concentration

Composite electrodes with different graphene (GN)/TiO2 ratios and nano-activated carbon electrodes were prepared for electrocatalytic performance comparison. The electrodes were loaded with platinum (Pt) by use of chloroplatinic acid to promote their performance. Reactive Black 5 (RBk5) dye wastewater was treated as a challenging pollutant by use of advanced electrochemical oxidation technology. The composite materials were characterized by Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscopy (FE-SEM), and Energy Disperse Spectroscopy (EDS). Results showed that the graphene electrode was prepared successfully and verified because all elements were uniformly loaded on the conductive carbon cloth. The effects of several operating parameters including material types, pH, initial concentration of RBk5, and current density on the removal performance of RBk5 were also assessed. The supporting electrolyte was NaCl solution of 1 g L−1. The concentration of RBk5 was detected using an ultraviolet spectrophotometer with a detection wavelength of 600 nm. The optimum parameters of the experiment were GN/TiO2 ratio of 1:4 and pH of 6.6. The removal efficiency of RBk5 could be higher than 95% under an initial concentration of RBk5 of 5 ppm and a current density of 2.5 mA·cm-2 when reaction time was 30 min.

Application of Mg-Al-LDH@MgFe2O4 Nanocomposite Supported on Gold Micron-Dendrites as an Efficient Electrocatalyst for Ethanol Oxidation

NANO ◽  
2020 ◽  
Vol 15 (03) ◽  
pp. 2050037
Author(s):  
Masoumeh Taei ◽  
Masoud Fouladgar ◽  
Foroozan Hasanpour ◽  
Fatemeh Hasheminasab
Keyword(s):  
Glassy Carbon ◽  
Current Density ◽  
Ethanol Oxidation ◽  
Carbon Electrode ◽  
Co Poisoning ◽  
Long Term Stability ◽  
Enhance Efficiency ◽  
A Current ◽  
Oxidation Of Ethanol

Mg-Al-LDH@MgFe2O4 nanocomposite was synthesized and was applied to enhance efficiency of gold micron-dendrites/glassy carbon electrode (Mg-Al-LDH@MgFe2O4/AuNDs/GCE) for oxidation of ethanol. Based on the results, Mg-Al-LDH@MgFe2O4/AuNDs showed a current density of 29.4[Formula: see text]mA cm[Formula: see text], which was 1.6 times higher than that on the surface of AuNDs/GCE. Also, long-term stability of the studied electrode showed that the nanocomposite improves CO-poisoning tolerance of the AuNDs. Accordingly, the Mg-Al-LDH@MgFe2O4/AuNDs catalyst exhibits an excellent potential for application in alkaline ethanol fuel cells.

In situ topotactic synthesis of a porous network Zn2Ti3O8 platelike nanoarchitecture and its long-term cycle performance for a LIB anode

CrystEngComm ◽  
2018 ◽  
Vol 20 (45) ◽  
pp. 7329-7336 ◽  
Author(s):  
Xingang Kong ◽  
Xing Wang ◽  
Dingying Ma ◽  
Jianfeng Huang ◽  
Jiayin Li ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Exchange Reaction ◽  
Current Density ◽  
Cycle Performance ◽  
Porous Network ◽  
Ion Exchange Reaction ◽  
Topotactic Transformation ◽  
A Current

Porous network Zn2Ti3O8 platelike nanoarchitecture was prepared by an ion exchange reaction and further in situ topotactic transformation, and it exhibited an enhanced reversibility capacity of 408 mA h g−1 after 1000 cycles at a current density of 1 Ag−1.

scholarly journals Study on Electromigration Effects and IMC Formation on Cu–Sn Films Due to Current Stress and Temperature

2020 ◽  
Vol 10 (24) ◽  
pp. 8893
Author(s):  
Zhao-Ying Wang ◽  
Nhat Minh Dang ◽  
Po-Hsun Wang ◽  
Terry Yuan-Fang Chen ◽  
Ming-Tzer Lin
Keyword(s):  
Intermetallic Compound ◽  
Growth Mechanism ◽  
Current Density ◽  
Structural Changes ◽  
Defect Formation ◽  
Copper Substrate ◽  
Signal Delay ◽  
Cross Sectional ◽  
Current Densities

In this study, the effects of electromigration on a solder/copper substrate due to temperature and current density stress were investigated. The copper–tin (Cu–Sn) film samples were subjected under a fixed current and various heating conditions (130 °C and 180 °C) and current densities (different cross-sectional areas). The micro-structural changes and intermetallic compound (IMC) formation were observed, and failure phenomena (brittle cracks, voids, bumps, etc.) on the structures of samples were discussed. The results showed that the IMC thickness increased as the temperature and current density increased. Moreover, it was found that the higher the temperature and current density was, the greater the defects that were observed. By adjusting the designs of sample structures, the stress from the current density can be decreased, resulting in reduced failure phenomena, such as signal delay, distortion, and short circuiting after long-term use of the material components. A detailed IMC growth mechanism and defect formation were also closely studied and discussed.

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