• Journal of Korean Society of Environmental Engineers
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• v.30 no.4
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• pp.409-414
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• 2008

Porous carbon electrode for electrosorption was prepared by a wet phase inversion method. Carbon slurry that was a mixture of activated carbon powder(ACP) and PVdF solution was cast directly upon a graphite sheet by means of a casting knife. Porous carbon electrodes were fabricated by immersing the cast film in pure water as a non solvent. Physical and electrochemical properties of carbon electrodes prepared with various ACP contents(50.0, 75.0, 83.3, 87.5, 90.0 wt %). From the SEM images we can verify that the electrode was porous. The average pore sizes determined for the electrodes fabricated with various ACP contents ranged from 72.7 to 86.4 nm and the size decreased as the ACP content increased. The electrochemical properties were characterized by cyclic voltammetry(CV) method. All of the voltammograms showed typical behavior of an electric double layer charging/discharging on the carbon surface. The capacitance increased with the ACP content and the values ranged from 2.18 F/cm$^2$ for 50 wt% ACP to 4.77 F/cm$^2$ for 90 wt% ACP.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.5
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• pp.731-738
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• 2011

Cholesterol is the precursor of various steroid hormones, bile acid, and vitamin D with functions related to regulation of membrane permeability and fluidity. However, the presence of excess blood cholesterol may lead to arteriosclerosis and hypertension. Moreover, dietary cholesterol may affect blood cholesterol levels. Generally, cholesterol determination is performed by spectrophotometric or chromatographic methods, but these methods are very time consuming and costly, and require complicated pretreatment. Thus, the development of a rapid and simple analysis method for measuring cholesterol concentration in food is needed. Multi-walled carbon nanotube (MWCNT) was functionalized to MWCNT-$NH_2$ via MWCNT-COOH to have high sensitivity to $H_2O_2$. The fabricated MWCNT-$NH_2$ was attached to a glassy carbon electrode (GCE), after which Prussian blue (PB) was coated onto MWCNT-$NH_2$/GCE. MWCNT-$NH_2$/PB/GCE was used as a working electrode. An Ag/AgCl electrode and Pt wire were used as a reference electrode and counter electrode, respectively. The sensitivity of the modified working electrode was determined based on the amount of current according to the concentration of $H_2O_2$. The response increased with an increase of $H_2O_2$ concentration in the range of 0.5~500 ${\mu}M$ ($r^2$=0.96) with a detection limit of 0.1 ${\mu}M$. Cholesterol oxidase was immobilized to aminopropyl glass beads, CNBr-activated sepharose, Na-alginate, and toyopearl beads. The immobilized enzyme reactors with aminopropyl glass beads and CNBr-activated sepharose showed linearity in the range of 1~100 ${\mu}M$ cholesterol. Na-alginate and toyopearl beads showed linearity in the range of 5~50 and 1~50 ${\mu}M$ cholesterol, respectively. The detection limit of all immobilized enzyme reactors was 1 ${\mu}M$. These enzyme reactors showed high sensitivity; especially, the enzyme reactors with CNBr-activated sepharose and Na-alginate indicated high coupling efficiency and sensitivity. Therefore, both of the enzyme reactors are more suitable for a cholesterol biosensor system.

• Journal of Electrochemical Science and Technology
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• v.3 no.3
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• pp.143-148
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• 2012

The unique effects of highly conductive conducting polymer/SWNT (single walled carbon nanotube) composite nanoparticles in electric double layer capacitors are studied for the enhancement of the adhesive properties, specific capacitance and power characteristics of the electrode. Because the conducting polymer/SWNT composite material, which is believed to act as a polymer binder, an active material for charge storage and a conducting agent, is well distributed on the activated carbon, greatly enhanced adhesion properties, cell capacitance and power characteristics were obtained.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.241-249
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• 2013

Ethanolamine (ETA) is widely used for alkalinization of water in steam cycles of nuclear power plants with pressurized water reactor. When ETA contained wastewater was released, it could increase COD and T-N. The treatment of the COD and T-N from ETA wastewater was investigated using the GAC as particle electrodes in three-dimensional electrode reactor (TDE). This study evaluated the effectiveness of GAC as particle electrode using different packing ratio at 300 V. The results showed that GAC-TDE could reduce ETA much more efficiently than ZVI-TDE at the mass ratio of GAC to insulator, 1:2. Additionally, The effect of applied electric potential to COD and T-N reduction was investigated. The results showed the high COD, T-N reduction and current efficiency at the low electric potential. Using the GAC-TDE will provide a better ETA reduction with reducing electrical potential dissipation.

• Korean Journal of Materials Research
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• v.19 no.10
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• pp.544-549
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• 2009

Activated carbon (AC) with very large surface area has high capacitance per weight. However, such activation methods tend to suffer from low yields, below 50%, and are low in electrode density and capacitance per volume. Carbon NanoFibers (CNFs) had high surface area polarizability, high electrical conductivity and chemical stability, as well as extremely high mechanical strength and modulus, which make them an important material for electrochemical capacitors. The electrochemical properties of immobilized CNF electrodes were studied for use as in electrical double layer capacitor (EDLC) applications. Immobilized CNFs on Ni foam grown by thermal chemical vapor deposition (CVD) were successfully fabricated. CNFs had a uniform diameter range from 50 to 60 nm. Surface area was 56 m$^2$/g. CNF electrodes were compared with AC and multi wall carbon nanotube (MWNT) electrodes. The electrochemical performance of the various electrodes was examined with aqueous electrolyte of 2M KOH. Equivalent series resistance (ESR) of the CNF electrodes was lower than that of AC and MWNT electrodes. The specific capacitance of 47.5 F/g of the CNF electrodes was achieved with discharge current density of 1 mA/cm$^2$.

• Proceedings of the Safety Management and Science Conference
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• 2003.11a
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• pp.343-350
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• 2003

The best Ppy weight ratio was 7 wt% and the optimal electrode composition ratio was 78 : 17 : 5 wt.% of (MSP-20 : BP-20 =1 : 1), (Super P : Ppy =10 : 7) and P(VdF-co-HFP). Implantation of Ppy as the conducting agents have led to superior electrochemical characteristics because of the low of internal resistance and faradaic capacitance. The result of unit cell with Ppy 7 wt% were as follows: 28.02 Fig of specific capacitance, 1.34 Ω of DC-ESR and 0.36 Ω of AC-ESR. Unit cell showed a good stability up to 200 charge-discharge cycles, retaining 82% of their original capacity at 200 cycles. From the analysis of impedance, the electrodes with Ppy 7 wt% showed low ESR, low charge transfer resistance and quick reaction rate. It was inferred that quick charge-discharge was possible. As compared with the specific capacitance (rectangular shape) of CV, it was also concluded that the specific capacitance originated from thecompound phenomena of the faradaic capacitance by oxidation and reduction of Ppy and the non-faradaic capacitance by adsorption-desorption of activated carbon.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.366-369
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• 1999

The purpose of this study is to research and develop V2Os-AC(activated carbon) composite electrode for supercapacitor. Supaercapacitor cell of V2Os-AC composite electrode with 25P70FLiCIO$_{4}$/PC$_{10}$/EC$_{10}$ polymer electrolyte bring out good capacitor Performance below 3V. The discharge capacitance of V2Os-AC(30:70) composite with 70wt.% AC in 1st and 200th cycles was 9.6 and 8.2 F/g at current density of 1m7/cm2. The capacitance of V$_2$O$_{5}$-AC composite with 70wt.% AC capacitor was larger than that of others. The coulombic efficiency of supercapacitor at discharge process of 1 and 200 cycles were 96 and 100%, respectively. V$_2$O$_{5}$-AC composite supercapacitor with 70wt.% AC content showed good capacitance and stability with cycling.ing.ing.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.13-16
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• 2006

Electro-electrodialysis (EED) experiments were carried out for the HI concentration from HIx $(HI-H_2O-I_2)$ solution to improve the Hl decomposition reaction in the thermochemical water-splitting is (iodine-Sulfur) process. EED cell is composed of the collector electrode and electrolyte. Nafion 117 which was cation exchange membrane used as an electrolyte, and the activated carbon cloth used as an electrode. The HI concentration experiment was carried out using the HIx solution and molar ratio of the $I_2$ were varied from 1 to 3 mole. The cell voltages were decreased as temperature increase. And, membrane properties such as transport number of proton and electro-osmosis coefficient were decreased as temperature increase

• Applied Chemistry for Engineering
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• v.19 no.2
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• pp.185-190
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• 2008

In order to increase the surface area of electrodes for electrosorption, porous carbon electrodes were fabricated by a wet phase inversion method. A carbon slurry consisting of a mixture of activated carbon powder (ACP), polyvinylidene fluoride (PVdF), and N-methyl-2-pyrrolidone (NMP) as a solvent was cast directly on a graphite sheet. The cast film was then immersed in pure water for phase inversion. The physical and electrochemical properties of the electrodes were investigated using scanning electron microscopy (SEM), porosimetry, and cyclic voltammetry. The SEM images verified that the pores of various sizes were formed uniformly on the electrode surface. The average pore sizes determined for the electrodes fabricated with various NMP contents ranged from 64.2 to 82.4 nm and the size increased as the NMP content increased. All of the voltammograms showed a typical behavior of charging and discharging characteristic at the electric double layer. The electrical capacitance ranged from 3.88 to $5.87F/cm^2$ depending on the NMP contents, and the electrical capacitance increased as the solvent content decreased. The experimental results showed that the solvent content is an important variable controlling pore size and ultimately the capacitance of the electrode.

• Analytical Science and Technology
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• v.8 no.4
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• pp.553-559
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• 1995

An extraction chromatographic method of separating rare earth impurities from high purity $Nd_2O_3$, $Sm_2O_3$, $Gd_2O_3$, $Er_2O_3$, $Dy_2O_3$ and $Yb_2O_3$ was studied by using $HCl-NH_4Cl$ as moving phase and P507 as stationary phase. After the impurities were enriched from the eluate by chelant-activated carbon, the active carbon was ashed and the ignited residue was used to prepare the sample electrode for spark source mass spectrometric determination. The impurities in 99.9999% rare earth oxide can be determined by the proposed method with recovery over 80%.