• Environmental Engineering Research
• /
• v.22 no.3
• /
• pp.312-319
• /
• 2017

The treatment of dyeing wastewater is not easy because dyes are mainly aromatic, heterocyclic compounds. The most effective technologies and methods to treat dyeing wastewater are costly and involve materials that are difficult to regenerate after use. Therefore, it is necessary to develop cost-effective, eco-friendly technologies to treat dyeing wastewater. The aim of this study was to investigate the removal of sulfur blue 11 (CI 53235) anionic dye using methyl esterified sericite (ME-sericite) adsorbents in an aqueous solution. The results are discussed in terms of the ME-sericite particle size, temperature, pH value and initial sorption rate according to the initial sulfur blue concentration. In addition, we analyzed the adsorption kinetics using a Pseudo-second-order model with the desorption and reusability. The methyl esterification caused a considerable increase in the specific surface area from 4.45 to $17.62m^2/g$. The ME-sericite adsorbents successfully removed > 98% of the sulfur dye in the aqueous solution. For the adsorption of 1 mg of sulfur dye, approximately 4.6 to 6.6 g/L ME-sericite were required. The desorption process was carried out by mixing a NaOH eluent to desorb 90.56% of the sulfur dye with 2 h of contact time. Thus, the ME-sericite is a promising adsorbent to treat dyeing wastewater due to its low dose requirement, high removal efficiency and inexpensive material.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.3
• /
• pp.907-911
• /
• 2013

Numbers of matrix- and analyte-derived ions and their sum in matrix-assisted laser desorption ionization (MALDI) of a peptide were measured using 2,5-dihydroxybenzoic acid (DHB) as matrix. As for MALDI with ${\alpha}$-cyano-4-hydroxy cinnamic acid as matrix, the sum was independent of the peptide concentration in the solid sample, or was the same as that of pure DHB. This suggested that the matrix ion was the primary ion and that the peptide ion was generated by matrix-to-peptide proton transfer. Experimental ionization efficiencies of $10^{-5}-10^{-4}$ for peptides and $10^{-8}-10^{-7}$ for matrices are far smaller than $10^{-3}-10^{-1}$ for peptides and $10^{-5}-10^{-3}$ for matrices speculated by Hillenkamp and Karas. Number of gas-phase ions generated by MALDI was unaffected by laser wavelength or pulse energy. This suggests that the main role of photo-absorption in MALDI is not in generating ions via a multi-photon process but in ablating materials in a solid sample to the gas phase.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.11a
• /
• pp.642-645
• /
• 2007

석탄, 폐기물 등 다양한 시료의 가스화 반응을 통해서 발생되는 합성가스는 CO, $H_2$, $CO_2$가 주성분으로 가스엔진, 가스터빈 등의 연료로 사용하여 발전하거나 합성반응을 통해 다양한 화학원료로의 전환이 가능하다. 합성가스를 가스엔진, 가스터빈, 연료전지등의 연료로 사용하는 경우는 고효율 발전이 가능하여 기존 연소방식의 발전과 비교하여 단위 전력 생산량 당 $CO_2$의 배출량이 감소 되며, 여기에 $CO_2$ 분리공정을 적용하면 $CO_2$ 배출량 감소효과를 극대화 할 수 있다. 화석연료의 연소 및 가스화 반응을 통해서 발생하는 이산화탄소의 분리에 대한 많은 연구가 진행되고 있으나, 본 연구에서는 흡착방식을 이용한 합성가스 내의 이산화탄소 분리를 위하여 흡착제를 이용한 이산화탄소의 흡착, 탈착 성능 분석 연구를 수행하였다. 합성가스내의 이산화탄소를 분리하기 위한 흡착제로는 NaX 계열의 zeolite를 이용하였으며, 가스화 반응을 통해 발생한 합성가스를 흡착제에 통과시켜 이산화탄소의 선택적 흡착 여부를 확인하였다. 또한 TPD(Temperature Programmed Desorption)방법을 이용하여 흡착제의 이산화탄소 흡착 성능을 분석하였다.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.4
• /
• pp.635-646
• /
• 2007

The reaction of gas-phase hydrogen atoms H with H atoms chemisorbed on a graphite surface has been studied by the classical dynamics. The graphite surface is composed of the surface and 10 inner layers at various gas and surface temperatures (Tg, Ts). Three chains in the surface layer and 13 chains through the inner layers are considered to surround the adatom site. Four reaction pathways are found: H2 formation, H-H exchange, H desorption, and H adsorption. At (1500 K, 300 K), the probabilities of H2 formation and H desorption are 0.28 and 0.24, respectively, whereas those of the other two pathways are in the order of 10-2. Half the reaction energy deposits in the vibrational motion of H2, thus leading to a highly excited state. The majority of the H2 formation results from the chemisorption-type H(g)-surface interaction. Vibrational excitation is found to be strong for H2 formed on a cold surface (~10 K), exhibiting a pronounced vibrational population inversion. Over the temperature range (10-100 K, 10 K), the probabilities of H2 formation and H-H exchange vary from 0 to ~0.1, but the other two probabilities are in the order of 10-3.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.10
• /
• pp.3059-3064
• /
• 2013

In this study transesterification of Triglycerides (TG) from Jatropha curcas oil (JCO) with methanol for production of biodiesel was investigated over cerium impregnated ZSM-5 catalysts. NaZSM-5 was synthesized in an alkaline medium and impregnated with cerium oxide by wet method using cerium nitrate as a source for cerium. They were characterized by X-ray diffraction (XRD), Thermogravimeteric analysis (TGA), $CO_2$-temperature programmed desorption, and $N_2$ adsorption/desorption analysis. XRD analysis showed decrease in intensity of the patterns with the increase in the ceria loading but crystallization of ceria to larger size is an evident for 10 and 15% loading. The optimal yield of transesterification process was found to be 90% under the following conditions: oil to methanol molar ratio: 1:12; temperature: $60^{\circ}C$; time: 1 h; catalyst: 5 wt %. Here the yield of fatty acid methyl ester (FAME) was calculated through $^1H$ NMR analysis. The investigation on catalyst loading, temperature, time and reusability illustrated that these ceria impregnated NaZSM-5's were found to be selective, recyclable and could yield biodiesel at low temperature with low methanol to oil ratio due to the presence of both Lewis and Bronsted basicity. Hence, from the above study it is concluded that ceria impregnated ZSM-5 could be recognized as a potential catalysts for biodiesel production in industrial processes.

• Transactions of the Korean hydrogen and new energy society
• /
• v.17 no.1
• /
• pp.39-46
• /
• 2006

Highly ordered Li dispersed nickel oxide nanotubes were prepared with anodic aluminum oxide (AAO) template for hydrogen storage. Electron microscope results showed that uniform length and diameter of nickel oxide nanotubes were obtained. The wall thickness and outer diameter of nickel oxide nanotubes are about 40 - 50 nm and 200 - 400 nm, respectively. It was observed that the diameter of nickel oxide nanotubes is bigger than the pore diameter of AAO template. Li dispersed nickel oxide were consisted of nanoflakes and had structures of nanotubes and nanorods. For increasing the hydrogen adsorption and desorption capacity, the Li dispersed nickel oxide nanotubes were fluorinated. The fluorinated Li dispersed nickel oxide nanotubes showed 1.65 wt% of the hydrogen adsorption capacities at 77 K under 47 atm.

• Journal of Korean Society for Atmospheric Environment
• /
• v.29 no.6
• /
• pp.757-772
• /
• 2013

In this study, a combination of sorbent tube (ST)-thermal desorption (TD)-gas chromatography (GC)-mass spectrometry (MS) was used for quantitative analysis of liquid phase standards of 10 BVOC ((1) (+)-${\alpha}$-pinene, (2) (+)-${\beta}$-pinene, (3) ${\alpha}$-phellandrene, (4) (+)-3-carene, (5) ${\alpha}$-terpinene, (6) p-cymene, (7) (R)-(+)-limonene, (8) ${\gamma}$- terpinene, (9) myrcene, and (10) camphene). The results of BVOC calibration yielded comparatively stable pattern with response factor (RF) of 23,560~50,363 and coefficient of determination ($R^2$) of 0.9911~0.9973. The method detection limit (MDL) of BVOC was estimated at 0.03~0.06 ng with the reproducibility of 1.30~5.13% (in terms of relative standard error (RSE)). Emissions of BVOC were measured from four types of fruit samples ((1) tangerine (TO), (2) tangerine peel (TX), (3) strawberry (SO), and (4) sepals of strawberry (SX)). The sum of BVOC flux (${\sum}flux$ (BVOC) in ng/hr/g) for each sample was seen on the descending order of (1) TX=291,614, (2) TO=2,190, (3) SO=1,414, and (4) SX=2,093. If the results are compared between the individual components, the highest flux was seen from (R)-(+)-limonene (265,395 ng/hr/g) from TX sample.

• Korean Chemical Engineering Research
• /
• v.48 no.4
• /
• pp.534-539
• /
• 2010

The adsorptive removal of organic sulfur compounds including tert-butylmercaptane(TBM), tetrahydrothiophene(THT) and dimethylsulfide(DMS) in methane was investigated over NaY and copper-exchanged NaY(CuNaY) zeolites at 303 K and atmospheric pressure. In the ternary adsorption system, the preferential adsorption of THT over other sulfur compounds on NaY and the concurrent adsorption of all sulfur compounds on CuNaY were achieved, which could be explained by the breakthrough curve, the temperature-programmed desorption, and the apparent activation energy for desorption. The sulfur uptake capacity of CuNaY(2.90~3.20 mmol/g) was much higher than that of NaY(0.70~0.90 mmol/g). A comparative study indicated that the $Cu^{1+}$ sites and acidity of CuNaY were probably responsible for the strong interaction with sulfur atom and high sulfur uptake abilities.

• Journal of the Korean Vacuum Society
• /
• v.6 no.2
• /
• pp.172-176
• /
• 1997

The change of surface structures for the deposition of indium on clean Si(111) surface is investigated as a function of substrate temperature and surface coverage by RHEED. We find that at substrate temperature of $400^{\circ}C$, $\sqrt{3}\times\sqrt{3},\sqrt{31}\times\sqrt{31},4\times 1$ structures are formed at indium coverages of 0.2, 0.3 and 0.5 ML, respectively. We also find that for the substrate temperature of $300^{\circ}C$, 4$\times$1 structure starts to be forme by 0.2 ML of indium, and the mixed structure of 4$\times$1 and $\sqrt{3}\times\sqrt{3}$is observed for more than 1.0 ML. On the other hand, if the indium is deposited on the Si(111)-$\sqrt{3}\times\sqrt{3}$ structure at room temperature, $2\times2\; and\;\sqrt{7}\times\sqrt{3}$ structures are found to form at 0.2 and 0.4 ML, respectovely. From the desorption process, the desorption energy of indium in Si $\sqrt{7}\times\sqrt{3}$ structure is observed to be 2.84 eV.

• Transactions of the Korean hydrogen and new energy society
• /
• v.28 no.3
• /
• pp.238-245
• /
• 2017

Mg-Ni nanoparticles were synthesized by a physical vapor condensation method (DC arc-discharge) in a mixture of argon and hydrogen atmosphere, using compressed mixture of micro powders as the raw materials. The crystal phases, morphology, and microstructures of nanoparticles were analyzed by means of X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). It was found that the intermetallic compounds of $Mg_2Ni$ and $Mg_2Ni$ formed with existence of phases of Mg, Ni, and MgO in Mg-Ni nanoparticles. After one cycle of hydrogen absorption/desorption process (activation treatment), Mg-Ni nanoparticles exhibited excellent hydrogen absorption properties. $Mg_2Ni$ phase became the main phase by aphase transformation during the hydrogen treatments. The phenomenon of refinement of grain size in the nanoparticle was also observed after the hydrogen absorption/desorption processes, which was attributed to the effect of volume expansion/shrinkage and subsequent break of nanoparticles. Maximum hydrogen absorption contents are 1.75, 2.21 and 2.77 wt.% at 523, 573 and 623 K, respectively.