• Title/Summary/Keyword: KOH activation

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De-Ash Characteristics using a Cleaning Agent KOH of CDPF for PM Reduction of Diesel Engines

  • Seo, Choong-Kil
    • Journal of Power System Engineering
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    • v.20 no.1
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    • pp.30-35
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    • 2016
  • The objective of this study is to investigate the physicochemical properties of the catalysts and the feasibility of remanufacturing them after removing ash in CDPF using a cleaning agent KOH. Compared with the carbon oxidation ability of fresh CDPF, that of de-ashed CDPF had an insignificant difference due to the low activation energy of CO and $CO_2$. As ash deposited in CDPF was de-ashed with KOH, it had a practical feasibility on remanufacturing point of view, but washcoat was melted about 26%. Further studies were required for the prevention of washcoat loss.

Removal of Cu and Pb Ions from Aqueous Solution by Waste Citrus Peel-based Activated Carbon (폐감귤박으로 합성한 활성탄에 의한 수용액 중의 Cu 및 Pb 이온의 제거)

  • Moon, Myung-Jun;Kam, Sang-Kyu;Lee, Min-Gyu
    • Journal of Environmental Science International
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    • v.27 no.6
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    • pp.401-410
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    • 2018
  • Waste citrus peel-based activated carbon (WCAC) was prepared from waste citrus peels by activation with KOH. The removal of Cu and Pb ions from aqueous solution by the prepared WCAC was investigated in batch experiments. The solution pH significantly influenced Cu and Pb adsorption capacity and the optimum pH was 4 to 6. The adsorption of Cu and Pb ions by WCAC followed pseudo-second-order kinetics and the Langmuir isotherm model. The maximum adsorption capacity calculated by Langmuir isotherm model was 31.91 mg/g for Cu and 92.22 mg/g for Pb. As the temperature was increased from 303 K to 323 K, the ${\Delta}G^{\circ}$ value decreased from -7.01 to -8.57 kJ/mol for Cu ions and from -0.87 to -2.06 kJ/mol for Pb ions. These results indicated that the adsorption of Cu and Pb by WCAC is a spontaneous process.

Influence of Chemical Activation of Carbon Supports on Electrochemical Behaviors of Pt-Ru Nanoparticle for Fuel cells (연료전지 백금-루테늄 나노입자의 전기화학적 거동에 대한 탄소지지체의 활성화 효과)

  • Kim, Byung-Ju;Park, Soo-Jin
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.93.2-93.2
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    • 2011
  • In this work, graphite nanofibers (GNFs) were prepared for using catalyst supports in fuel cells. The GNFs were chemically activated to obtain high surface area and small pore diameter with different potassium hydroxide (KOH) amounts, i.e., 0, 1, 3, 4, and 5 g as an activating agent. And then Pt-Ru was deposited onto activated GNFs (A-GNFs) by chemical reduction method. The characteristics of Pt-Ru catalysts deposited onto A-GNFs were determined by specific surface area and pore size analyzer, X-ray diffraction (XRD), transmission electron microscopy (TEM), and inductive coupled plasma-mass spectrometer (ICP-MS). The electrochemical properties of Pt-Ru/A-GNFs catalysts were also analyzed by cyclic voltammetry (CV) experiments. From the results, the A-GNFs carbon supports activated with 4 g of KOH (A4g-GNFs) showed that the highest specific surface areas. In addition, the A4g-GNFs led to uniform dispersion of Pt-Ru onto A4g-GNFs, resulting in the enhancement of electrochemical activity of Pt-Ru catalysts.

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Effect of Chemical Activation on Electrochemical behaviors of Ni-loaded Graphite Nanofibers (화학적 활성화에 따른 Ni 담지된 흑연나노섬유의 전기화학적 거동)

  • Yoo, Hye-Min;Park, Soo-Jin
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.159.2-159.2
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    • 2011
  • In this study, we prepared the activated graphite nanofibers (A-GNFs) via chemical activation with KOH reagent. The effect of A-GNFs on the surface and textural properties of Ni-loaded graphite nanofibers (Ni/GNFs) was investigated by X-ray diffraction (XRD), transmission electron microscope (TEM), and Brunauer-Emmett-Teller (BET). The textural properties of samples were investigated by $N_2$/77K adsorption isotherms. The electrochemical performances were investigated by cyclic voltammetry. As a results, the electrochemical performances of Ni/GNFs were improved with usage of A-GNFs. This could be interpreted by the high specific surface area and large total pore volume of the A-GNFs.

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Electrochemical Potentiostatic Activation & Its Application for Enhancing blue LED Efficiency

  • Kim, Bong-Jun;Kim, Hak-Jun;Lee, Yeong-Gon;Baek, Gwang-Seon;Lee, Jun-Gi;Kim, Jin-Hyeok;Sadasivam, Karthikeyan Giri
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2010.05a
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    • pp.56.1-56.1
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    • 2010
  • A novel electrochemical potentiostatic method has been examined in order to enhance the hole concentration of p-type GaN thin films using KOH and HCl electrolyte. The hole concentration was increased more than 2 times by the electric voltge apply with the mobility of $10{\sim}12cm^2/V.s$. At optimum condition of 3V apply, hole concentration was enhanced more than reference sample from $1.7{\times}10^{-17}cm^{-3}$ to $4.1{\times}10^{-17}cm^{-3}$. Application of this activation method to blue-LED fabrication improved optical output from 18.4mW to 20.6mW, that is ~12% increase. SIMS analysis indicates that nearly 70% of hydrogen atoms could be removed by this method.

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Development of Bio-AC Filter for Heavy Metal Adsorption (중금속 제거에 우수한 바이오 활성탄 필터의 개발)

  • Kim, Hak-Hee;Yoon, Kyung-Sik
    • 유체기계공업학회:학술대회논문집
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    • 2003.12a
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    • pp.541-546
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    • 2003
  • Activated carbon was prepared from coffee wastes by chemical activation with $ZnCl_{2}$, NaOH and KOH. The coffee wastes was used as raw material. Preparation process involves the roasting of raw material and carbonization of roasted material followed by chemical activation. N2-BET surface areas of activated coffee char prepared by chemical activation was measured as $1,110{\sim}2,442m^{2}/g$. Removal of copper and chromium in solution by activated carbon was carried out and structural change of pore surface was observed by SEM.

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Electrochemical Characteristics of Highly Porous Carbon Prepared by Chemical Activation Method for EDLC (화학적 활성법으로 제조된 EDLC용 고다공성 탄소전극의 전기화학 특성)

  • Eo, Soo-Mi;Kim, Han-Joo;Oh, Seung-Mo;Park, Soo-Gil
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.2010-2012
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    • 2005
  • Activated carbon was activated with chemical treatment to attain high surface area with porous structure. We have been considered activated carbon is the ideal material for high voltage electric double layer capacitor due to their high specific surface area, good conductivity and chemical stability. In this study we found that increase in electrochemical capacitance due to activated carbon. Also chemically activated carbon and water treatment have resulted larger capacitance and also exhibits better electrochemical behavior, and is about 15% more than in untreated state. The structural change in activated carbon through chemical treatment activation was investigated by using SEM and XRD. In this study, the dependence of the activation behavior with KOH in the micro structure of host materials will be discussed. Furthermore, the relation to the electric double layer capacitance, especially the specific capacitance per unit area, is also discussed.

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Effects of Activation of Gluteus Maximus and Abdominal Muscle using EMG Biofeedback on Lumbosacral and Tibiocalcaneal Angles in Standing Position

  • Koh, Eun-Kyung;Weon, Jong-Hyuck;Jung, Do-Young
    • The Journal of Korean Physical Therapy
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    • v.25 no.6
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    • pp.411-416
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    • 2013
  • Purpose: The purpose of the present study was to determine the effects of activation of gluteus maximus (Gmax) and abdominal muscle using EMG biofeedback on lumbosacral and tibiocalcaneal angles in standing position. Methods: Fourteen healthy subjects with normal feet participated in the present study. Electromyographic (EMG) biofeedback using visual cue was used to activate the external oblique (EO) and Gmax. The lumbosacral and tibiocalcalcaneal angles were measured by electronic goniometers. All the subjects were instructed to activate the Gmax and EO monitoring increasing amounts of the muscle activities in each muscle. The lumbosacral and tibiocalcaneal angles were collected in three trials during resting and activation of each muscle using EMG biofeedback in standing position. The mean value of three trials was used in the data analysis. A paired-t test was used to compare the lumbosacral and tibiocalcaneal angles between resting and activation of the Gmax and EO using EMG biofeedback. Results: The lumbosacral and tibiocalcaneal angles were significantly less in the resting compared to activation using EMG biofeedback (p<0.05). Conclusion: The activaition of Gmax and abdominal muscles using EMG biofeedback play role to control the pronation of subtalar joint during the weight-bearing.