• Journal of Korean Society of Water and Wastewater
• /
• v.21 no.4
• /
• pp.375-383
• /
• 2007

Treatment efficiency research was performed using Fenton process and the electrochemical process in the presence of ferrous ion and hydrogen peroxide for the industrial wastewater including 1,4-Dioxane produced during polymerization of polyester. The Fenton process and the electrochemical Iron Redox Reaction (IRR) process were applied for this research to use hydroxyl radical as the powerful oxidant which is continuously produced during the redox reaction with iron ion and hydrogen peroxide. The results of $COD_{Cr}$ and the concentration of 1,4-Dioxane were compared with time interval during the both processes. The rapid removal efficiency was obtained for Fenton process whereas the slow removal efficiency was occurred for the electrochemical IRR process. The removal efficiency of $COD_{Cr}$ for 310 minutes was 84% in the electrochemical IRR process with 1,000 mg/L of iron ion concentration, whereas it was 91% with 2,000 mg/L of iron ion concentration. The lap time to remove all of 1,4-Dioxane, 330 mg/L in the wastewater took 150 minutes with 1,000 mg/L of iron ion concentration, however it took 120 minutes with 2,000 mg/L of iron ion concentration in the electrochemical IRR process.

• Applied Chemistry for Engineering
• /
• v.29 no.4
• /
• pp.363-368
• /
• 2018

Polyoxometalates (POMs) have outstanding properties and a great deal of potential for electrochemical applications. As POMs are highly soluble, the implementation of POMs in various functional materials is required to fully use their potential in electrochemical devices. Here, we will review the recently developed immobilization methods to incorporate POMs into conductive nanomaterials, such as nanocarbons and conducting polymers. Various immobilization strategies involve POMs entrapped in conducting polymer matrix and integration of POMs into nanocarbons using a Langmuir-Blodgett technique, a layer-by-layer self-assembly, and an electrochemical in-situ polymerization. In addition, we will review a variety of electrochemical applications including electrocatalysts for water oxidation, lithium-ion batteries, supercapacitors, and electrochemical biosensors.

• Korean Journal of Materials Research
• /
• v.28 no.1
• /
• pp.50-61
• /
• 2018

Various carbon aerogels (CAs) were prepared from polymerization of resorcinol and formaldehyde and applied as the electrode materials of an electric double layer capacitor (EDLC) with the aim of controlling the textural and electrochemical properties of CAs by the type of base catalyst and the ratio of resorcinol to catalyst (R/C). The CAs from $NaHCO_3$ and $KHCO_3$ with $H^+$ ions had higher specific surface areas but exhibited lower electrochemical properties than those from $K_2CO_3$ and $Na_2CO_3$, which had more uniform pore size distributions. The electrochemical properties of $Na_2CO_3$ were superior to those of $K_2CO_3$ probably because the polarizing power of $Na^+$ ions was higher than $K^+$ ions. With an increasing R/C ratio, the pore sizes of CA showed a tendency to increase but the uniformity of the pore size distribution got worse. For the four base catalysts, the highest electrochemical property was obtained at the R/C ratio of 500.

• Journal of the Korean Chemical Society
• /
• v.38 no.12
• /
• pp.885-890
• /
• 1994

Kinetics of electrochemical polymerization of aniline on a tungsten electrode in acidic aqueous solution was studied by means of cyclic voltammetry and kinetic measurements of anodic oxidation. Aniline molecule appeared to be intially oxidized via two-electron transfer to produce oxidized deprotonated aniline ion, which subsequently undergoes nucleophilic attack to the parent aniline and results in head to tail coupling to yield a dimerized species. But, being contrary to the case of Pt electrode, the propagation of polymerization occured through attack of the monomer by the oxidized aniline monomer to polymer. The growth rate of polyaniline was slow in comparison with the growth on Pt electrode. The degradation products were confirmed to be not p-benzoquinone(BQ) but p-phenylenediamine(p-PDA) by spectrophotometry, which agrees with the fact that oxidation of p-PDA was not observed below 1.0 V.

• Macromolecular Research
• /
• v.11 no.6
• /
• pp.481-487
• /
• 2003

Polypyrrole (PPy) was coated sequentially by chemical and electrochemical methods on a woven fabric, giving rise to a fabric having high electrical conductivity. We investigated the effects of the preparation conditions on the various properties of the resulting fabric. The PPy-coated fabric with optimum properties was obtained when it was prepared sequentially by chemical polymerization at the elevated temperature of 100$^{\circ}C$ under a pressure of 0.9 kgf/$\textrm{cm}^2$ and then electrochemical polymerization with a 3.06 mA/$\textrm{cm}^2$ current density at 25 $^{\circ}C$ for 2 hrs with the separator plate. The surface resistivity of the resulting fabric was as low as 5 Ω/$\square$ .The PPy-coated fabric prepared under the optimum conditions showed practically applicable heat generating property. When electrical power was supplied to the fabric using a commercial battery for a mobile phone (3.6 V, LGLl-AHM), the temperature of the fabric increased very quickly from room temperature to ca. 55 $^{\circ}C$ within 2 min and was maintained for ca. 80 min at that temperature. The heat generating property of the fabric was extremely stable, exhibiting similar behavior over 10 repeated cycles. Therefore, we suggest that the PPy-coated fabric in this study may be practically useful for many applications, including flexible, portable surface-heating elements for medical or other applications.

• Journal of the Korean Electrochemical Society
• /
• v.10 no.4
• /
• pp.252-256
• /
• 2007

A series of spherical porous carbons were prepared via resorcinol-formaldehyde (RF) sol-gel polymerization in the presence of cationic surfactant (CTAB, cetyltrimethylammonium bromide), wherein the carbon sphere size was controlled by varying the CTAB introduction time after a pre-determined period of addition reaction (termed as "pre-curing"). The sphere size gradually decreases with an increase in the pre-curing time within the range of 30-150 nm. The carbons possess two types of pores; one inside carbon spheres (intra-particle pores) and the other at the interstitial sites made by carbon spheres (inter-particle pores). Of the two, the surface exposed on the former was dominant to determine the electric double-layer capacitor (EDLC) performance of porous carbons. As the intra-particle pores were generated inside RF gel spheres by gasification, the pore diameter was similar for all these carbons, thereby the pore length turned out to be a decisive factor controlling the EDLC performance. The charge-discharge voltage profiles and complex capacitance analysis consistently illustrate that the smaller-sized RF carbons deliver a better rate capability, which must be the direct result of facilitated ion penetration into shorter pores.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.5
• /
• pp.1228-1232
• /
• 2010

The nanocomposites of polypyrrole (PPy) and multi-walled carbon nanotube (MWCNT) with different composition are synthesized by the chemical oxidative polymerization method. In these composites, the MWCNTs are uniformly coated by PPy with different thickness. The electrochemical properties of the composite electrodes are investigated by cyclic voltammetry, galvanostatic charge-discharge cycling and electrochemical impedance spectroscopy. The full cells assembled with the PPy/MWCNT composite electrodes deliver initial specific capacitances ranging from 146.3 to 167.2 F/g at 0.5 mA/$cm^2$ and exhibit stable cycling characteristics. The effect of content of MWCNT in the composite on cycling performance of the cells is also investigated.

• Journal of the Korean Electrochemical Society
• /
• v.9 no.4
• /
• pp.137-140
• /
• 2006

In order to overcome the weak actuation and relaxation problems during the deformation of IPMC actuator, polymeric anion (polystyrenesulfonate)-doped polypyrrole(Ppy(PSS)) was electrodeposited onto IPMC actuator. Electrochemical quartz crystal microbalance study showed that hydrated cations were instilled into Ppy(PSS) film and polymeric-anion dopants introduced during polymerization were not expelled. Ppy(PSS)-coated IPMC actuator formed two electrode/electrolyte interfaces, Pt/nafion and Ppy(PSS)/bulk solution, and additive volume expansion phenomena at interfaces induced the large deformation compensating the relaxation of actuation by back diffusion of water.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.5
• /
• pp.1097-1100
• /
• 2009

New types of conducting polyaniline-polymannuronate (PANI-PM) composites were synthesized by in situ deposition techniques in an aqueous media. By dissolving different weight percentage of polymannuronate (PM) (5, 10, 15, and 25%), the oxidative polymerization of aniline was carried out using ammonium per sulfate as an oxidant. The obtained composites were studied for their thermal stability and electrochemical behavior. The thermal stability of PANI-PM composites is lower than PANI, which supports a strong interaction between PANI and PM. However, the composites show an appreciable electrochemical behavior. Based on these observation the PANI-PM composites can be explored in different fields such as electric devices, sensors, functional coatings, etc.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.07a
• /
• pp.909-912
• /
• 2000

We synthesized polypyrrole (PPy) nanotubules by oxidative polymerization of the pyrrole monomer within the pores of a polycarbonate template. The electrochemical behavior was investigated using cyclic voltammetry. The redox potential was about -0.5 V vs. Ag/AgCl reference electrode, while the potential was about 0 V for PPy film. It is considered as the backbone grows according to the pore wall. Therefore, it is possible to be arranged regularly. That leads to improvement in the electron hopping. By electrochemical doping of glucose oxidase (GOx) on PPy nanotubules, an enzyme electrode has been fabricated. The kinetic parameter of biochemical reaction with glucose was evaluated. The formal Michaelis constant and maximum current calculated by computer were about 11.4 mmol $dm^3$ and 170.85 A respectively. Obviously, an affinity for the substrate and current response of the PPy nanotubules enzyme electrode are rather good, comparing with that of PPy film.