Treatment of As(V) and As(III) by electrocoagulation using Al and Fe electrode

2009 ◽  
Vol 60 (5) ◽  
pp. 1341-1346 ◽  
Author(s):  
W. H. Kuan ◽  
C. Y. Hu ◽  
M. C. Chiang
Keyword(s):  
Passive Film ◽  
Potentiodynamic Polarization ◽  
Electrode Materials ◽  
Initial Period ◽  
Electrode System ◽  
Initial Solution ◽  
Alkaline Condition ◽  
Bipolar Electrode ◽  
Pitting Potential ◽  
Fe Hydroxide

A batch electrocoagulation (EC) process with bipolar electrode and potentiodynamic polarization tests with monopolar systems were investigated as methods to explore the effects of electrode materials and initial solution pH on the As(V) and As(III) removal. The results displayed that the system with Al electrode has higher reaction rate during the initial period from 0 to 25 minutes than that of Fe electrode for alkaline condition. The pH increased with the EC time because the As(V) and As(III) removal by either co-precipitation or adsorption resulted in that the OH positions in Al-hydroxide or Fe-hydroxide were substituted by As(V) and As(III). The pH in Fe electrode system elevate higher than that in Al electrode because the As(V) removal substitutes more OH position in Fe-hydroxide than that in Al-hydroxide. EC system with Fe electrode can successfully remove the As(III) but system with Al electrode cannot because As(III) can strongly bind to the surface of Fe-hydroxide with forming inner-sphere species but weakly adsorb to the Al-hydroxide surface with forming outer-sphere species. The acidic solution can destroy the deposited hydroxide passive film then allow the metallic ions liberate into the solution, therefore, the acidic initial solution can enhance the As(V) and As(III) removal. The over potential calculation and potentiodynamic polarization tests reveal that the Fe electrode systems possess higher over potential and pitting potential than that of Al electrode system due to the fast hydrolysis of and the occurrence of Fe-hydroxide passive film.

Pitting Corrosion of Zn Peculiarly Caused by Acetate Anions

2016 ◽  
Vol 230 (10) ◽  
Author(s):  
Hesham S. Abdel-Samad ◽  
Hamdy H. Hassan
Keyword(s):  
Passive Film ◽  
Pitting Corrosion ◽  
Potentiodynamic Polarization ◽  
Corrosion Behaviour ◽  
Passive Layer ◽  
Acetate Solution ◽  
Layer Formation ◽  
Potentiodynamic Polarization Curve ◽  
Pitting Potential ◽  
Formation Region

AbstractThe corrosion behaviour of zinc metal was studied in acetate solutions. The potentiodynamic polarization curve in 0.1 M acetate solution displays an anodic peak (A1) owing to the anodic dissolution of zinc followed by a passive layer formation region. Breakdown of the passive film and the initiation of pitting corrosion were observed beyond the pitting potential (

The preparations of nanoporous carbon with multi-heteroatoms co-doping from black liquor powders for supercapacitors

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Pengfei Hao ◽  
Yanjie Yi ◽  
Youming Li ◽  
Yi Hou
Keyword(s):  
High Performance ◽  
Electrode Materials ◽  
Black Liquor ◽  
Nanoporous Carbon ◽  
Electrode System ◽  
Industrial Wastes ◽  
Co Doping ◽  
Paper Making ◽  
Symmetric Supercapacitor

Abstract A green and economically viable route without any additional activation agents and templates has been developed to synthesize biomass-derived nanoporous carbon for superior electric double-layer capacitors via direct pyrolysis of dried black liquor powders, which is the main waste in pulping and paper-making industry. The resulting carbon materials present hierarchical porosity and moderate specific surface area of 1134  m 2 g − 1 {\text{m}^{2}}\hspace{0.1667em}{\text{g}^{-1}} , as well as multi-heteroatoms co-doping such as N, S, Na and K, which exist originally in black liquor. When evaluated as electrode materials for supercapacitors in 6 M KOH aqueous electrolyte, the-prepared carbon samples deliver a significantly high gravimetric capacitance of 331  F g − 1 \text{F}\hspace{0.1667em}{\text{g}^{-1}} at 0.5  A g − 1 \text{A}\hspace{0.1667em}{\text{g}^{-1}} in a three-electrode system. Moreover, the fabricated symmetric supercapacitor also possesses a gravimetric capacitance of 211  F g − 1 \text{F}\hspace{0.1667em}{\text{g}^{-1}} at 0.5  A g − 1 \text{A}\hspace{0.1667em}{\text{g}^{-1}} , with an impressive long-term cycling stability of 92 % capacitance retention after 3000 cycles. This work explores a suitable and scalable approach for mass production of high-performance electrode materials with industrial wastes on the base of cost-efficiency and environment-friendship.

Development of a Split Bipolar Electrode System for Electrochemical Fluorination of Triphenylmethane

2018 ◽  
Vol 6 (1) ◽  
pp. 97-100 ◽  
Author(s):  
Kazuhiro Miyamoto ◽  
Hiroki Nishiyama ◽  
Ikuyoshi Tomita ◽  
Shinsuke Inagi
Keyword(s):  
Electrode System ◽  
Bipolar Electrode ◽  
Electrochemical Fluorination

Studies on Corrosion Behavior of S-165 and HP Supermartensitic Stainless Steels in Cl- Environment

2011 ◽  
Vol 695 ◽  
pp. 425-428
Author(s):  
Duo Wang ◽  
De Ning Zou ◽  
Chang Bin Tang ◽  
Kun Wu ◽  
Huan Liu
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Behavior ◽  
Stainless Steels ◽  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
Polarization Curves ◽  
Chemical Compositions ◽  
Pitting Potential ◽  
Potentiodynamic Polarization Curves

Supermartensitic stainless steel grades are widely used in oil and gas industries to substitute duplex and super duplex stainless steels these years. In this paper the corrosion behavior of supermartensitic stainless steels with different chemical compositions, S-165 and HP, was investigated in Cl-environment. All the samples were treated by quenching at 1000 °C followed by tempering at 630 °C for 2h. After heat treatment, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) were determined on both kinds of samples. Polarization curves shows that the metastable pitting nucleuses were formed in passive area and the Cr content is the most important factor leading to the differences of pitting potential. The potentiodynamic polarization curves were conducted at various NaCl contents (5000, 15000 and 35000 ppm) and emphasized the need to account for the Cl-sensitivity of samples under corrosion environment. The results show that, the pitting potential decrease with the increase of chloride contents. The behavior of passive film was analyzed by electrochemical impedance spectroscopy.

scholarly journals Front Cover: Simultaneous Multiplex Potentiostatic Electroanalysis with Liquid-Junction-Removed Reference Electrode System using a Closed Bipolar Electrode (ChemElectroChem 16/2018)

2018 ◽  
Vol 5 (16) ◽  
pp. 2157-2157
Author(s):  
Kumi Y. Inoue ◽  
Miho Ikegawa ◽  
Takahiro Ito-Sasaki ◽  
Shinichiro Takano ◽  
Hitoshi Shiku ◽  
...  
Keyword(s):  
Reference Electrode ◽  
Electrode System ◽  
Bipolar Electrode ◽  
Liquid Junction ◽  
Front Cover

Corrosion Behaviour of Ti6Al4V and TiMo10Zr4 Alloys in the Ringer’s Solution: Effect of pH and Plastic Strain

2015 ◽  
Vol 227 ◽  
pp. 435-438 ◽  
Author(s):  
Joanna Loch ◽  
Alicja Łukaszczyk ◽  
Vincent Vignal ◽  
Halina Krawiec
Keyword(s):  
Corrosion Resistance ◽  
Plastic Strain ◽  
Titanium Alloys ◽  
Passive Film ◽  
Current Density ◽  
Potentiodynamic Polarization ◽  
Corrosion Behaviour ◽  
Ringer’S Solution ◽  
Ph Values

The corrosion behaviour of titanium alloys is not well understood – especially the role of the microstructure and plastic strain. In this paper, the influence of the microstructure and plastic strain on the corrosion resistance of TiMo10Zr4 and Ti6Al4V alloys was studied in the Ringer’s solution at 37 °C. Measurements were performed for different pH values and in aerated and de-aerated solutions using potentiodynamic polarization techniques. Results obtained on the two alloys were compared. It was shown that in the absence of plastic strain TiMo10Zr4 shows better corrosion resistance than Ti6Al4V (especially for pH = 8). By contrast, the current density in the passive range measured after 8% plastic strain was greater on TiMo10Zr4 than on Ti6Al4V, indicating that the passive film on TiMo10Zr4 is less protective than that formed on Ti6Al4V.

Uniformity Analysis of the Passive Film for SS316 Stainless Steel

2007 ◽  
Vol 364-366 ◽  
pp. 215-220
Author(s):  
Shuo Jen Lee ◽  
J.J. Lai ◽  
Yu Ming Lee ◽  
Ming Der Ger ◽  
S.W. Cheng
Keyword(s):  
Stainless Steel ◽  
Passive Film ◽  
Stainless Steels ◽  
Traditional Method ◽  
Local Corrosion ◽  
Pitting Potential ◽  
Corrosion Resistant ◽  
Potential Test

Passive film of stainless steels possesses good corrosion resistant property. However, the passive film formed in nature is not uniform and the quality is not consistent. It is the major causes for local corrosion. The pitting potential test is a traditional method to test local corrosion of stainless steels. The local corrosion is usually induced by the break-down of the passive film. Therefore, it can be utilized to evaluate the quality of the passive film. Also, because the pitting test is quick and inexpensive, many tests can be performed to evaluate the uniformity of the passive film. This study focuses on SS316 stainless steel. The specimens were treated with electropolishing processes. The original and the processed specimens were tested by pitting potential tests. From these results, the distribution and the uniformity of passive film could be evaluated. An efficient and inexpensive index of the uniformity of the passive film is proposed.

scholarly journals Simultaneous Multiplex Potentiostatic Electroanalysis with Liquid-Junction-Removed Reference Electrode System using a Closed Bipolar Electrode

2018 ◽  
Vol 5 (16) ◽  
pp. 2161-2161
Author(s):  
Kumi Y. Inoue ◽  
Miho Ikegawa ◽  
Takahiro Ito-Sasaki ◽  
Shinichiro Takano ◽  
Hitoshi Shiku ◽  
...  
Keyword(s):  
Reference Electrode ◽  
Electrode System ◽  
Bipolar Electrode ◽  
Liquid Junction
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