• Title/Summary/Keyword: 콜로이드법

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Removal of Lead from Sea Water using Electrolysis and Coprecipitation Method (전기분해와 공침법을 이용한 해수중의 납 제거)

  • Jin, Hong-Sung;Lee, Jae-Ho
    • Journal of Korean Society of Environmental Engineers
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    • v.32 no.2
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    • pp.149-154
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    • 2010
  • The feasibility of lead removal by electrolytic coprecipitation was investigated. Electrolysis bath was divided into anode and cathode chamber with anion exchange resin filled membrane. Sea water was electrolyzed and pH of the electrolyte in cathode chamber was increased. Consequently it induced the formation of $Mg(OH)_2$ and $CaCO_3$. The colloidal type precipitates, hich have high surface area, adsorbed lead ions in sea water and coprecipitated. Sea water electrolyses were conducted at different current density. Concentrations of Mg, Ca and Pb in the solution were measured with titration and ASV method. Morphology and crystallography were analyzed with SEM, EDS and XRD. As pH and current density increased, most of lead ions in the sea water were successfully removed.

Preparation and Interface Properties of Colloidal Silica (콜로이드 실리카의 제조 및 계면특성)

  • Lee, Han Chul;Kim, Jong Hyub;Chang, Yoon Ho
    • Applied Chemistry for Engineering
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    • v.17 no.4
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    • pp.386-390
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    • 2006
  • Colloidal silica which has high surface area and excellent surface properties are chemically stable inorganic materials and used for various applications in industry. Silica sol was prepared from sodium silicate solution by acid neutralization method and ion exchange treatment to remove sodium ions. Through the experimental analysis for controlling factors of particle growth rate, such as temperature, pH, and aging time, the uniform size distribution of silica sol could be obtained. The size distribution and shape of silica sol was measured by TEM and dynamic light scattering method. Zeta potential change and gelling phenomena of silica sol and its rheological properties also investigated.

Isothermal Drying Rate and Copolymerization of Vinyl Acetate/Alkyl Methacrylates (비닐 아세테이트/알킬메타크릴레이트계 공중합과 등온건조속도)

  • Kim, Min-Sung;Seul, Soo-Duk
    • Polymer(Korea)
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    • v.33 no.3
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    • pp.230-236
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    • 2009
  • Water soluble vinyl acetate/alkyl methacrylate copolymers were prepared by the emulsion copolymerization of vinyl acetate and various methacrylates such as methyl methacrylate (MMA) and ethyl methacrylate (EMA). Potassium persulfate (KPS) and ammonium persulfate (APS) were used as an initiator. Poly (vinyl alcohol) (PVA) was used as a protective colloid. The drying characteristics of the prepared poly(vinyl acetate-co-methyl methacrylate) (PVAc/PMMA), poly(vinyl acetate-co-ethyl methacrylate) (PVAc/PEMA) were studied using moisture meter at the temperature between 100 and $200^{\circ}C$. The significant results are described as follows. The activation energy of the isothermal drying process of the copolymers has the order of PVAc/PMMA> PVAc/PEMA> PVAc.

Fabrication of Hollow Micro-particles with Nonspherical Shapes by Surface Sol-gel Reaction (표면 솔-젤 반응을 활용한 마이크로미터 크기의 비구형상 공동 입자의 제조)

  • Cho, Young-Sang;Jeon, Seog-Jin;Yi, Gi-Ra
    • Korean Chemical Engineering Research
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    • v.45 no.6
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    • pp.611-618
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    • 2007
  • We demonstrate the sol-gel coating technique of colloidal clusters for producing hollow micro-particles with complex morphologies. Cross-linked amidine polystyrene (PS) microspheres were synthesized by emulsifier-free emulsion copolymerization of styrene and divinylbenzene. The amidine PS particles were self-organized inside toluene-in-water emulsion droplets to produce large quantities of colloidally stable clusters. These clusters were coated with thin silica shell by sol-gel reaction of tetraethylorthosilicate (TEOS) and ammonia, and the organic polystyrene cores were removed by calcination at high temperature to generate nonspherical hollow micro-particles with complex morphologies. This process can be used to prepare hollow particles with shapes such as doublets, tetrahedra, icosahedra, and others.

Nano-Sized Mullite(3Al2O3.42SiO2) Colloids Fabricated by Spray Combustion Synthesis (SCS) Technique (분무연소합성(SCS)법에 의한 나노크기 물라이트(3Al2O3.42SiO2) 콜로이드 제조)

  • Lee, Sang-Jin;Jun, Byung-Sei
    • Journal of the Korean Ceramic Society
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    • v.41 no.4
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    • pp.297-301
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    • 2004
  • Nano-sized mullite (3Al$_2$O$_3$$.$2SiO$_2$) colloids were prepared by use of the spray combustion method. For combustion reaction, Al(NO$_3$)$_3$$.$9$H_2O$, and CH$_{6}$N$_4$O were used as an oxidizer and a fuel respectively, and then colloidal silica was also added as 2SiO$_2$source for mullite. The temperature of the reaction chamber was kept at 80$0^{\circ}C$ to initiate the ignition of droplets of the mixed precursors. For preventing droplet coagulation, the droplet number concentration was reduced using the metal screen filter, and the residence time of aerosol was kept at 2.5 seconds for laminar flow. The synthesized colloidal particles had an uniform spherical shape with 130 nanometer size and the crystalline phase showed the mullite with stoichiometry in the observations of XRD and TEM.

Fabrication of Nano-sized ZnO Colloids from Spray Combustion Synthesis (SCS) (분무연소합성(SCS)법에 의한 나노크기 산화아연(ZnO) 콜로이드의 제조)

  • Lee, Sang-Jin;Lee, Sang-Won;Jun, Byung-Sei
    • Journal of the Korean Ceramic Society
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    • v.41 no.1
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    • pp.76-80
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    • 2004
  • Nano-sized ZnO colloids were prepared by use of spray combustion method. for combustion reaction, $Zn(NO_3)_2{\cdot}6H_2O$ and $CH_6N_4O$ were employed as an oxidizer and a fuel. Exothermic peak was shown at $230^{\circ}C$ by DTA/TGA, and it was considered as a combustion reaction followed by ignition of the precursor mixture. In case of spray combustion method, because insufficient contents of molecules and radicals generated from precursor droplets may lead an incomplete igmition, the ignition temperature of combustion chamber was chosen at $500^{\circ}C$. For diminishing aerosol coagulation, the droplet number concentration was reduced by filter media. The fluid was laminar with 2.5 seconds of aerosol residence time. The synthesized colloids had spherical shape with 180 nanometer size, and the crystalline phase was ZnO with hexagonal structure.

A Study on the RuO2 Electrode Catalyst Prepared by Colloidal Method (콜로이드법으로 합성한 RuO2 전극촉매의 연구)

  • PARK, JIN-NAM
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.3
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    • pp.193-200
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    • 2019
  • $RuO_2$, $PtO_2$, and various $(Ru,Pt)O_2$ colloidal solution were prepared using modified Watanabe method. Electrodes were manufactured by dipping of Ni mesh into the colloidal solution. Manufactured electrodes were characterized by XRD, SEM, and EDS. $(Ru,Pt)O_2$ electrodes showed $RuO_2$ crystal structure and high roughness. The hydrogen evolution reaction (HER) activities were evaluated by Linear Sweep Voltammetry. 1Ru2Pt electrode showed similar activity with commercial electrode, HER potentials are -0.9 V for both.

Catalytic Performance of Iron-Based Fischer-Tropsch Catalysts Promoted by $SiO_2$ Using Different Sources ($SiO_2$ 원료물질에 따른 Fischer-Tropsch 합성반응용 Fe계 촉매의 성능변화)

  • Chun, Dong Hyun;Kim, Hak-Joo;Hyun, Sun-Taek;Lee, Ho-Tae;Yang, Jung-Il;Yang, Jung Hoon;Jung, Heon
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.114.1-114.1
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    • 2010
  • Fe계 촉매는 FT(Fischer-Tropsch) 합성반응에 매우 유망한 촉매로 주목받고 있으며, $280^{\circ}C$ 미만의 저온 FT 합성반응의 경우, 침전법이 Fe계 촉매의 가장 전형적인 제조방법으로 알려져 있다. Fe계 촉매에 첨가되는 조촉매로는 Cu, K, $SiO_2$ 등이 가장 대표적이며, 이 중에서 특히 구조 조촉매로 첨가되는 $SiO_2$는 Fe계 촉매의 기계적 강도를 향상시킬 뿐만 아니라, 촉매의 성능에도 크게 영향을 미치는 것으로 보고되고 있다. 본 연구에서는 침전법을 이용하여 저온 FT 합성반응용 Fe계 촉매를 제조하였고, 구조 조촉매로 첨가한 $SiO_2$의 원료물질에 따른 Fe계 촉매의 성능변화를 조사하였다. $SiO_2$의 원료물질로는 콜로이드 $SiO_2$와 분말 $SiO_2$를 이용하였으며, 분말 $SiO_2$를 이용한 촉매가 콜로이드 $SiO_2$를 이용한 촉매보다 다소 높은 CO 전환율 및 중질탄화수소 선택도를 나타내는 것을 확인하였다.

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Electrochemical Characteristics of the Oxygen Electrode for Alkaline Fuel Cells -Impregnation of Silver Catalyst on Carbon Black with Colloidal Method- (알칼리형 연료전지용 산소극의 전기화학적 특성고찰 -콜로이드 방법에 의한 카본블랙상 은촉매담지-)

  • Lee, Hong-Ki;Lee, Ju-Seong
    • Applied Chemistry for Engineering
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    • v.3 no.4
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    • pp.701-709
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    • 1992
  • Silver particles were impregnated on carbon black with colloidal method and used as catalyst for oxygen electrode in alkaline fuel cell. With the addition of sodium dodecylbenzenesulfonate in $AgNO_3$ and $NaBH_4$solution, colloidal solution was made and confirmed with electrophoresis test. Effects of particle size on electrode performance were studied and $200{\AA}$ of silver particle size shown the highest value of mass activity. The aggromeration of silver particle was Influenced with surfactant amount, stirring time and heat treatment. Considering the increase of particle size caused of operating temperature, recommendable particle size of silver catalyst for manufacturing the electrode was $100{\AA}$. Dispersity of carbon black was investigated and reagglomeration was appeared after homogenizing 30 sec.

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