• Clean Technology
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• v.19 no.3
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• pp.347-350
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• 2013

Desorption characteristics for ions adsorbed onto sericite was performed by means of $HNO_3$ solution which was selected as the best desorbing agent in the previous work. Elution of nickel ions adsorbed onto sericite using $HNO_3$ solution was confirmed by means of scanning electron microscopy (SEM) & energy dispersive X-ray spectroscopy (EDX) analysis. Desorption efficiency for nickel ions was 100% at the 20 mM of concentration. Also, nickel ions was completely desorbed within 1.0 of S/L (mg/mL) ratio which is defined as the ratio of adding amount of adsorbent and volume of desorbing agent and desorption process was quickly carried out within 60min. Finally, removal efficiency of reused sericite for nickel ions was constantly maintained until the 4th cycle.

• Journal of the Korean Ceramic Society
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• v.47 no.2
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• pp.169-176
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• 2010

The Fe-treated CNT/$TiO_2$ photocatalysts mixed with anatase and rutile phase have been developed for the decomposition of non-biodegradable different organic dyes like methylene blue (MB), rhodamine B (Rh.B), and methyl orange (MO) in two conditions as ultraviolet and visible light respectively. The results indicate that all the Fe-CNT/$TiO_2$ composites proved to be more efficient photocatalysts since degradation of MB at higher reaction rates, tthe decomposition rate of different dyes increases with an increase of $Fe^{3+}$ concentration in composites the highest rate of decomposition of different dyes was noted under UV irradiation. These results can indicate that the large CNT network is facilitate the electron transfer and strongly adsorb dye molecules on the texted photocatalysts, iron is reactive in the photo-Fenton process resulting in high production of OH radicals and also high activity of the photocatalyst. And Fe particles can generate more photoinduced electrons to conduction band of $TiO_2$ under visible light irradiation. The composites of Fe-CNT/$TiO_2$ photocatalysts synthesized by a sol-gel method were characterized by BET, TEM, SEM, XRD and EDX.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.209-213
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• 2014

A graft copolymer of poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) was synthesized via atom transfer radical polymerization (ATRP) and used as a structure-directing agent to prepare $Al@Fe_2O_3$ core-shell nanocomposites through a sol-gel process. The amphiphilic property of PVC-g-POEM allows for good dispersion of Al particles and leads to specific interaction with iron ethoxide, a precursor of $Fe_2O_3$. Secondary bonding interaction in the sol-gel composites was characterized by Fourier transform-infrared (FT-IR) spectroscopy. The well-organized morphology of $Al@Fe_2O_3$ core-shell nanocomposites was observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Energy dispersive X-ray (EDX) and X-ray diffraction (XRD) were used to analyze the elemental composition and crystallization structure of the composites.

• Journal of Hydrogen and New Energy
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• v.19 no.6
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• pp.482-489
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• 2008

Ti-Cr alloys consist of BCC solid solution, C36, C14 and C15 Laves phase at high temperature. Among others, the BCC solid solution phase was reported to have a high hydrogen storage capacity. However, activation, wide range of hysteresis at hydrogenation/dehydrogenation, and degradation of hydrogen capacity due to hydriding/dehydriding cycles must be improved for its application. In this study, to improve such problems, we added a Nb. For attaining target materials, Ti-10Cr-xNb(x=1, 3, 5wt.%) specimens were prepared by arc melting. The arc melting process was carried out under argon atmosphere. As-received specimens were characterized using XRD(X-ray diffraction), SEM(Scanning Electron Microscopy) with EDX(Energy Dispersive X-ray) and TG/DSC(Thermo Gravimetric Analysis/Differential Scanning Calorimetry). In order to examine hydrogenation behavior, the PCI(pressure-Composition-Isotherm) was performed at 293, 323, 373 and 423K.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.252-255
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• 2004

Various Semiconductor/Metal structured nanowires were synthesized from the simple thermal annealing of ball-milled compound powders and the thermal evaporation of metals. Their structural properties were investigated by Scanning Electron Microscopy(SEM) and Transmission Electron Microscopy(TEM), Energy Dispersive X-ray spectroscopy(EDX). Depending on the type of metals and the material of nanowires, uniform somiconductor/metal nanowires(GaN/Al, GaN/Ag) or isolated metal particles on semiconductor nanowires$(SnO_2/Ti,\;Si/Ti)$ were formed on the surface of nanowires.

• Carbon letters
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• v.7 no.3
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• pp.180-187
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• 2006

The treatment of piggery wastes was carried out at pilot scale using a multilayered metal-activated carbon system followed by carbon bed filtration. The physicochemical properties were obtained from treated samples with aqueous solutions containing metallic ions such as $Ag^+$, $Cu^{2+}$, $Na^+$, $K^+$ and $Mn^{2+}$, which main obsevations are subjected to inspect surface properties, color removal properties by Uv/Vis and EDX. Multilayered metal-activated carbons were contacted with waste water to investigation of the simultaneous catalytic effect for the COD, BOD, T-N and T-P removal. The removal results for the piggery waste using multilayered metal-activated carbon bed was achieved the satisfactory removal performance under permitted values of Ministry of Environment of Korea. The high efficiency of the multilayered metal-activated carbon bed was determined by the performance of this material for trapping, catalytic effect and adsorption of organic solid particles.

• Journal of the Korean Ceramic Society
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• v.53 no.2
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• pp.227-233
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• 2016

In order to make a highly ordered three-dimensional porous structure of titania ceramics, porogen beads of PS [Polystyrene] and PMMA [poly(methylmetacrylate)] were prepared by emulsion polymerization using styrene monomer and methyl methacrylate monomer, respectively. The uniform beads of PS or PMMA latex were closely packed by centrifugation as a porogen template for the infiltration of titanium butoxide solution. The mixed compound of PS or PMMA with titanium butoxide was dried and the dry compacts were calcined at $450^{\circ}C-750^{\circ}C$ according to the firing schedule to prepare micro- and meso- structures of polycrystalline titania with monodispersed porosity. Inorganic frameworks composed of $TiO_2$ were formed and showed a three Dimensionally Ordered Microstructure [3DOM] of $TiO_2$ ceramics. The pulverized particles of the $TiO_2$ ceramic skeleton were characterized using XRD analysis. A monodispersed crystalline micro-structure with micro/meso porosity was observed by FE-SEM with EDX analysis. The 3DOM $TiO_2$ skeleton showed opalescent color tuning according to the direction of light.

• Journal of the Korean Ceramic Society
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• v.48 no.1
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• pp.6-13
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• 2011

In this study, we used activated carbon (AC) and charcoal (CH) as carbon sources with $TiO_2$ powder to prepare spherical carbons containing titania (SCCT) by using phenolic resin (PR) as a bonding agent. The physicochemical characteristics of the SCCT samples were examined by BET, XRD, SEM, EDX, iodine adsorption and compressive strength. The photocatalytic activity was evaluated by measuring the removal efficiency of three kinds of organic dyes: methylene blue (MB), methyl orange (MO) and rhodamine B (Rh.B) under a UV/SCCT system. In addition, evaluation of chemical oxygen demand (COD) of piggery waste was done at regular intervals and gave a good idea about the mineralization of wastewater.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.102-102
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• 2008

Sapphire (${\alpha}-Al_2O_3$) has been used as the substrate of opto-electronic device because of characteristics of thermal stability, comparatively low cost, large diameter, optical transparency and chemical compatibility. However, there is difficulty in the etching and patterning due to the physical stability of sapphire and the selectivity with sapphire and mask materials [1,2]. Therefore, sapphire has been studied on the various fields and need to be studied, continuously. In this study, the etching properties of sapphire substrate were investigated with various $CH_4$/Ar gas combination, radio frequency (RF) power, DC-bias voltage and process pressure. The characteristics of the plasma were estimated for mechanism using optical emission spectroscopy (OES). The chemical compounds on the surface of sapphire substrate were investigated using energy dispersive X-ray (EDX). The chemical reaction on the surface of the etched sapphire substrate was observed by X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) was used to investigate the vertical and slope profiles.

• Journal of Korea Foundry Society
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• v.34 no.2
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• pp.60-66
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• 2014

A Zr-based amorphous alloy specimen was produced by vacuum die casting process. The salt spray test was carried out using the specimens in the as-cast, $Al_2O_3$ and $ZrO_2$ particle blasted state. Using these specimens, the SEM-EDX and XRD analyses, DSC measurement and bending strength test were conducted. After the salt spray test, the specimens were not experienced phase change and thermal characteristics of the alloys were remained unchanged. In the as-cast specimen, corrosion products were not observed. However, in the $Al_2O_3$ particle blasted specimen, pitting corrosion occurred and the detected corrosion products were $ZrCl_2$ and $NaZrO_3$. Due to the salt spray test, bending strength of the $Al_2O_3$ blasted specimens showed about 100 MPa lower strength than the other specimens. The bending fracture surface was vein pattern which was shown typically in the amorphous alloys.