• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.2
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• pp.141-146
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• 2002

We synthesized polypyrrole (PPy) by electrolysis of the pyrrole monomer solution containing support electrolyte, KCl and/or p-toluene sulfonic acid sodium salt (p-TS). The electrochemical behavior, was investigated using cyclic voltammetry and AC impedance. In the case of using electrolyte p-TS, the oxidation potential of the PPy was about -02 V vs Ag/AgCl reference electrode, while the potential was about 0 V for using electrolyte KCl. The falloff of the oxidation potential gave a sign of an improvement in the electron hopoing mechanism on the backbone. The AC impedance plot gave a hint of betterment of mass transport. PPy doped with p-TS improved in mass transport or diffusion. That was because the PPy doped with p-TS was more porous than PPy with KCl. We attained an effect of good kinetic parameters, in the case of PP-GOx enzyme electrodes doped with p-TS, which were determined by 58 mmol dm$\^$-3/ for apparent Michaelis constant and by 581 ㎂ for maximum current respectively.

• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.86-92
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• 2012

A characteristic study of chlorine dioxide generation by the electrolysis system was performed after chlorite ($ClO_2^-$) is adsorbed from sodium chlorite by a polymer ion exchange resin. A strongly basic anion exchange resin was used and a Ti plate coated with Ru and Ir was used as an electrode. Various parameters such as reaction stirring velocity, reaction temperature, chlorine dioxide product concentration, ion exchange resin content and product maker type for the adsorption quantity in the chlorite adsorption of ion exchange resin were investigated and found the ion exchange resin with the maximum adsorption quantity. A generation trend of chlorine dioxide was observed by the electrolysis system and optimum conditions on the desired value were found using response surface design of DOE (Design of Experiments). The strongly basic anion exchange resin with the maximum adsorption quantity was SAR-20 (TRILITE Gel type II) and the adsorption quantity was around 110 mg/IER (g). Observed generation optimum conditions of chlorine dioxide were constant-current (electrode area base; $A/dm^2$) and flow rate of $N_2$ gas (4.7 L/min) at the desired value of sterilization (900~1000 ppm, 1 h).

• Korean Journal of Materials Research
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• v.7 no.2
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• pp.114-120
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• 1997

Perovskite $BaTiO_3$ thin films on stainless steel substrate were prepared by using electrochemical reduction method in solution of $TiCl_4\;and\;Ba(N0_3)_2$. According to current density and electrolysis time. the morphology and thickness of film were varied. Ra/'Ti atomic ratio in $BaTiO_3$ film was controlled by Ha/Ti atomic ratio in solution. Although the excess $TiO_2{\cdot}nH_2O$ film was coated in initial stage of electrolysis. UiilTi atomic ratio in film was nearly constant in later stage. $BaTiO_3$ film precursor was obtained under the condition of $1OmA/cm^2$ current density and Smin electrolysis time. $BaTiO_2$ thin films with perovskite phase were formed 11,. the heat treatment above $500^{\circ}$.

• Journal of the Korean Chemical Society
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• v.35 no.2
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• pp.158-164
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• 1991

The reduction mechanism at a mercury electrode of o-cresolphthalexon(OCP) in strongly alkaline supporting electrolytes has been investigated by several electrochemical techniques. The radical formed after first one electron reduction uptake, dimerizes. The result of cyclic voltammetric investigation demonstrated the reversible nature of the electron transfer and standard rate constant was $3.27{\times}10^{-2}$ cm/sec. The apparent irreversible behavior of the second wave is a result of the existence of a fast protonation following the second electron transfer. At low concentration of OCP(< $1{\times}10^{-4}$M), cathodic current were remarkably adsorptive properties. Prolonged electrolysis was carried out at controlled potential of -1.85V, original violet color of the solution becames progressively weaker, and then colorless solution. The final product of an exhaustive electrolysis is electro-inactive. The appearence of four steps may be explained by the fact that the reduction of OCP elucidated ECEC mechanism.

• The Korean Journal of Food And Nutrition
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• v.13 no.4
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• pp.360-364
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• 2000

We studied the degree of rancidity of linoleic acid for the electrochemical redox reaction in time course and the kinetic parameters. The current of the linoleic acid was increased and the potential was shifted to the positive potential when scan rates were faster. The redox reaction of the linoleic acid was proceeding to totally irreversible and diffusion controlled reaction. From these results, diffusion coefficient(D$\_$o/) of linoleic acid was observed to 2.61$\times$10$\^$-6/ ㎠/s in the 0.1 M TEAP/DMF electrolyte solution. Also, exchange rate constant(K$\^$o/) was observed to 9.79$\times$10$\^$-11/ cm/s. The leaving time in air condition was found to affect the rancidity. We predicted that the product was carbonyl compounds.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.287-292
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• 2017

The electrodeposition of Zn on the automotive parts has been adapted However, because Zn electrodeposit needs to increase thickness for corrosion protection, it has problem of destruction of electrodeposit Zn-based electrodeposit have teen studied for corrosion protection and decreasing electrodeposit thickness. Especially; Zn-Co electrodeposit have much attention In this study, the Composition of Zn-Co electrodeposit in various manufacturing condition such as temperature, current density and electrolyte content was investigated to understand effect of electrolysis condition on Co content of specimen. The results were explained by cathode overvoltage and diffusion coefficient. As the current density increases, the electrolyte temperature decreases, and as the electrolyte concentration decreases, the overvoltage of the cathode increases. As the overvoltage of the cathode increases, the concentration polarization becomes more important than the activation polarization. Concentration polarization is determined by the diffusion of the mass transfer in the diffusion layer. In a constant concentration polarization, a large amount of elements with a large diffusion coefficient is diffused. That is, as the overvoltage of the cathode increases, the Zn content having a large diffusion coefficient increases.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.5
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• pp.486-491
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• 2004

Dimensionally stable anode(DSA) can be used for the hydro-metallurgy of non-ferrous metals like as Zn, and the electrolysis of sea water. MnO$_2$ electrode satisfies the requirements of DSA, and has a good cycle life and a low overpotential for oxygen evolution. MnO$_2$ electrodes based on Ti matrix were prepared by using thermal decomposition method and also MnO$_2$ was coated on Ti and Pb matrix with DMF and PVDF compositions. The MnO$_2$ electrodes prepared by thermal decomposition method had very weak adhesive strength onto Ti matrix and MnO$_2$ layer was removed out so that electrochemical properties for MnO$_2$ were not investigated. The viscosity of solvent used as a binder of MnO$_2$ Powder increased with the increasing PVDF contents. The thickness of the MnO$_2$ layer on Pb matrix in DSA, which was prepared with 5 times dipping at the solution mixed with PVDF : DMF = 1 : 9, was 150${\mu}{\textrm}{m}$. When the ratio of PVDF to MnO$_2$ was lower than 1 : 6, the Pb electrode didn't show any reaction irrespective of the concentrations of DMF. However, When the ratio of PVDF to MnO$_2$ was higher than 1: 6, the Pb electrode showed constant current reactions and homogeneous cyclic voltammetry even though at a high cycle. The reason for the high current and homogeneous cyclic voltammetry is the good catalytic reactions of MnO$_2$ powder in electrode.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.82-84
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• 2002

Dimensionally stable anode(DSA) can be used for the electrowinning of non-ferrous metal like as a Zn, and electrolysis of sea water. $MnO_2$ electrode satisfies the requirements of DSA, and has a good cycle life and a low overpotential for oxygen evolution. $MnO_2$ electrodes coated with DMF and PVDF based on Pb alloy produced at several compositions and dry temperatures. The viscosity of solvent used as a binder of $MnO_2$ powder increased with the increasing PVDF contents. When the ratio of PVDF to BMF with the 5 times dipping at the solution mixed with PVDF and DMF was 1/9, the coating thickness was $150{\mu}m$. When the ratio of PVDF to $MnO_2$ was lower than 1/6, the electrode didn't show any reaction irrespective of the concentrations of DMF. However, When the ratio of PVDF to $MnO_2$ was higher than 1/6, the electrode showed a constant current reactions and homogeneous cyclic voltammetry even though at a high cycle. The reason for the high current and homogeneous cyclic voltammetry is the good catalytic reactions of $MnO_2$ powder in electrode. The reactions of Pb electrode coated with $MnO_2$ and PVDF based on the pure Pb electrode.

• Resources Recycling
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• v.13 no.1
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• pp.28-38
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• 2004

The characteristics of cyanide decomposition in aqueous phase by electric oxidization have been explored in an effort to develop a process to recycle waste water. Considering current efficiency and voltage, the free cyanide decomposition experiment by electric oxidization indicated that 5 V of voltage and copper catalytic Cu/CN mole ratio 0.05 was the most appropriate condition, where current efficiency was 26%, and decomposition speed was 5.6 mM/min. High voltage and excess copper addition increased decomposition speed a little bit but not current efficiency. The experiment of free cyanide density change proves that high density cyanide is preferred because speed and current efficiency increase with density. Also, the overall decomposition reaction could be represented by the first order with respcect to cyanide with the rate constant of $1.6∼7.3${\times}$10^{-3}$ $min^{-1}$ The mass transfer coefficient of electric oxidization of cyanide came out as $2.42${\times}$10^{-5}$ $min^{-1}$ Furthermore, the Damkohler number was calculated as 5.7 in case of 7 V and it was found that the mass transfer stage was the rate determining step.

• Resources Recycling
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• v.31 no.3
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• pp.61-72
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• 2022

We investigated the electrochemical behavior of Sn (93.0 %)-Ag (4.06 %)-Cu (0.89 %) during electrolysis of Pb-free solder waste to recover tin and silver. A thin strip of the solder waste produced by high-temperature melting and casting was used as a working electrode to perform electrochemical analysis. During anodic polarization, the current peak of an active region decreased with an increase in the concentration of sulfuric acid used as an electrolyte. This resulted in the electro-dissolution of the working electrode in the electrolyte (1.0 molL^-1 sulfuric acid) for a constant current study. The study revealed that the thickening of an anode slime layer at the working surface continuously increased the electrode potential of the working electrode. At 10 mAcm^-2, the dissolution reaction continued for 25 h. By contrast, at 50 mAcm^-2, a sharp increase in the electrode potential stopped the dissolution in 2.5 h. During dissolution, silver enrichment in the anode slime reached 94.3% in the 1 molL^-1 sulfuric acid electrolyte containing a 0.3 molL^-1 chlorine ion, which was 12.7% higher than that without chlorine addition. Moreover, the chlorine enhanced the stability of the dissolved tin ions in the electrolyte as well as the current efficiency of tin electro-deposition at the counter electrode.