• Journal of the Korean Chemical Society
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• v.25 no.2
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• pp.92-96
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• 1981

The reactions of adsorbed oxygen species, $O_2^-$ and $O^-$, with propylene on ZnO were studied by EPR spectroscopy and temperature programmed desorption technique. Propylene interacts with adsorbed $O_2^-$ at $25^{\circ}C$ and the surface intermediate was decomposed to CO, $H_2$, $CO_2$ and $CH_4$ by raising the temperature above $200^{\circ}C$, while $O^-$ gave the products of complete oxidation, $CO_2$ and $H_2O$ above $300^{\circ}C$.

• Korean Chemical Engineering Research
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• v.47 no.5
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• pp.646-650
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• 2009

Hydrocarbon gases generated from the gasification of waste could be converted into $CO_2$ and $H_2$ using reforming catalysts and then $CO_2$ was selectively adsorbed and removed to obtain pure hydrogen. To optimize adsorption efficiency for $CO_2$ removal, $Na_2CO_3$ was supported on nanoporous alumina and the efficiency was compared with commercial alumina(Degussa). Nanoporous adsorbents formed more uniform pores and larger surface area compared to adsorbents using commercial alumina. The increase of $Na_2CO_3$ loading improved adsorption of $CO_2$. Finally, the highest adsorption capacity per unit mass of $Na_2CO_3$ could be achieved when the loading of $Na_2CO_3$ reached up to 20wt%. When the content of $Na_2CO_3$ increased above 20 wt%, it aggregated on the surface, and the pore volume was decreased. Used adsorbents could be recycled by the thermal treatment.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.457-462
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• 2022

Manganese (Mn) exists in various oxidation states and Mn(II) is the most mobile species of Mn, which is toxic to plants and limits their growth. Therefore, the purpose of this study was to reduce Mn toxicity by immobilizing Mn using various adsorbents including iron oxides and calcium compounds. Ferrihydrite, schwertmannite, goethite were synthesized, which was confirmed by X-ray diffraction. Hematite was purchased and used as Mn adsorbent. Calcium compounds such as CaNO₃, CaSO₄, and CaCO₃ were used to increase pH and oxidize Mn. For Mn adsorption, Mn(II) solution was reacted with four iron oxides, CaNO₃, CaSO₄, and CaCO₃ for 24 hours, filtered, and the remaining Mn concentrations in the solution were analyzed by inductively coupled plasma optical emission spectroscopy. The adsorption rate and adsorption isotherm were calculated. Among iron oxides, the adsorption rate was highest for hematite followed by ferrihyrite, but goethite and schwertmannite did not adsorb Mn. In the case of calcium compounds, the adsorption rate was high in the order of CaCO₃>CaNO₃>CaSO₄. In conclusion, treatment of CaCO₃ was the most effective in reducing Mn toxicity by increasing pH.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.658-662
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• 2009

In this work, the amine-treated activated carbon nanotubes (A-MWNTs) were used to investigate the $CO_2$ adsorption behaviors. A-MWNTs were prepared by impregnation with amine in methanol after chemical activation methods using a KOH. The characteristics of amine-treated A-MWNTs were studied by X-ray photoelectron spectroscopy (XPS), $N_2$ adsorption, desorption isotherms at 77 K. The specific surface area and pore volume of the A-MWNTs were analyzed by BET equation, BJH method, and t-plot method. $CO_2$ capture capacity as a function of temperature was measured by temperature programmed desorption (TPD). From the results, the amine treatment increased the basicity and nitrogen content of the A-MWNTs. The $CO_2$ adsorption capacity of the amine-nontreated A-MWNTs showed the highest value at room temperature and then greatly decreased with increasing the temperature. However, the amine-treated A-MWNTs presented a softer slope with temperature compared to the amine-nontreated ones. It was due to the strong interactions between $CO_2$ and amino groups presented on the carbon surfaces studied.

• Analytical Science and Technology
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• v.12 no.1
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• pp.7-12
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• 1999

The cation-exchange adsorbent (CEA) was prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto polypropylene (PP) fabric and its subsequently phosphonation. The adsorption characteristics of $Pb^{2+}$, $Cu^{2+}$ and $Co^{2+}$ for the CEA were discussed. In the grafting of GMA onto PP fabric, the degree of grafting (%) increased with increasing reaction time, reaction temperature, and pre-irradiation dose. The maximum grafting yield was observed around 60% GMA concentration. The content of phosphoric acid ranges from 2.5 to 3.5 mmol/g with the 85% phosphoric acid. The adsorption of $Pb^{2+}$, $Cu^{2+}$ and $Co^{2+}$ by the CEA was enhanced with increasing phosphoric acid content. The order of adsorption capacity of CEA was $Pb^{2+}$>$Co^{2+}$>$Cu^{2+}$.

• Journal of the Korean Institute of Gas
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• v.4 no.2 s.10
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• pp.27-32
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• 2000

In this study, $Mn_3O_4$ was synthesized by the different equivalent ratios using solution of $MnCL_2 {\cdot} 4H_2O$ and NaOH. We have investigated the crystal structure and surface area by XRD, BET Method, studied on the decompositon and adsorption of carbon dioxide with synthesized $Mn_3O_4$. As the results, we surveyed that main peak was $Mn_3O_4$, some Peaks were $MnO_2$ and $Mn_5O_8$ The specific surface area was ranged from $13.92m^2/g$ to $32.33m^2/g$. The decomposition of $CO_2$ was observed by the differential equivalent ratios at $450^{\circ}C$. $CO_2$ was well decomposed at equivalent ratio of 0.75. The amount of chemisorption of $CO_2$ was ranged from 2.885 to 19.628cc/g. Optimal equivalent ratio was 1.00 for the chemisorption of $CO_2$.

• Clean Technology
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• v.17 no.4
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• pp.389-394
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• 2011

A compact adsorption-based process for removal of carbon dioxide and nitrogen from natural gas has been discussed. Among the adsorption-based processes, especially, the pressure swing adsorption (PSA) process has been a suitable unit operation for the purification and separation of gas because of low operation energy and cost. A step cycle is made up of pressurization, feed, equalization, blowdown and rinse. In this work, the PSA process is composed of zeolite 13X and carbon molecular sieve (CMS) for removal of carbon dioxide and nitrogen from mixed gas containing $CH_4/CO_2/N_2$ (75:21:4 vol%). A CMS selectively removes carbon dioxide and a zeolite 13X separates nitrogen from methane. CMS is investigated experimentally due to the high throughput of the faster diffusing component ($CO_2$). The gas composition of top, bottom and feed tank was measured with the gas chromatography (GC) using TCD detector, helium as carrier gas and packed column for analysis of methane, carbon dioxide, and nitrogen.

• Journal of the Korean Chemical Society
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• v.28 no.2
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• pp.114-120
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• 1984

The reversible oxygenation of a solid stae polymeric cobalt(II) porphyrin complex, PVP-CoTPP was studied at 0, -24 and $-78^{\circ}C$. When PVP-CoTPP was contacted with $O_2 $at$-78^{\circ}C$ the oxygen uptake increased with oxygen partial pressure. At about 700mmHg $O_2$, the amount of oxygen taken up corresponded approximately one oxygen molecule to one Co(II) complex. The amount of $O_2$ taken up by PVP-CoTPP decreased with increasing temperature. When $16O_2$ was admitted to the Co(II) complex a EPR signal corresponding to $O_2^-$ increased with a decrease in Co(II) signal. The results suggest that an electron is transfered from Co(II) in PVP-CoTPP to oxygen forming a $Co(III)-O_2^-$ complex where $O_2^- $is superoxide type.

• Clean Technology
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• v.25 no.4
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• pp.296-301
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• 2019

This study was conducted to investigate the characteristics of CO oxidation by NO poisoning in Pt/TiO₂ catalyst prepared by wet impregnation method and calcined at 400 ℃. In order to confirm the NO poisoning effect of the Pt/TiO₂ catalyst, the change of reaction activity was observed when NO was injected during the CO+O₂ reaction where it was ascertained that the CO conversion rate rapidly decreased below 200 ℃. Also, CO conversion was not observed below 125 ℃. Recovery of initial CO conversion was not verified even if NO injection was blocked at 125 ℃. Accordingly, various analyses were performed according to NO injection. First, as a result of the TPD analysis, it was confirmed that NO pre-adsorption in catalyst inhibited CO adsorption and conversion desorption from adsorbed CO to CO₂. When NO was pre-adsorbed, it was confirmed through H₂-TPR analysis that the oxygen mobility of the catalyst was reduced. In addition, it was validated through FT-IR analysis that the redox cycle (Pt²⁺→Pt⁰→Pt²⁺) of the catalyst was inhibited. Therefore, the presence of NO in the Pt/TiO₂ catalyst was considered to be a poisoning factor in the CO oxidation reaction, and it was determined that the oxygen mobility of the catalyst is required to prevent NO poisoning.

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.33-35
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• 2012

본 연구에서는 전이금속 Cu, Mn이 함침된 제올라이트를 사용하여 일산화탄소의 흡착능을 연구하였다. 금속 복합 산화물촉매 제조는 Cu, Mn을 서로 다른 비율로 물리 혼합하여 지지체에 담지하였다. 제올라이트 분자체는 상용 13X를 사용하였다. 함침방법은 과잉용액 함침법을 사용하였고, 건조 후 소성 하여 산화물 형태로 담지하였다. 합성된 개질 흡착제의 표면특성 분석은 $N_2$흡착 및 탈착곡선을 통한 질소흡착 특성 분석으로 기공크기, 기공분포, 비표면적을 구하였으며, FT-IR, X-선 회절분석, 전자주사현미경, $NH_3$-TPD/TPR 으로 특성을 분석하였다. 흡착 실험은 고정층 반응기에서 수행하였으며, 내경 4 mm 석영관에 흡착제를 충진하고 흡착파과곡선을 Gas Chromatograph로 측정하여 Cu-Mn 제올라이트 촉매의 일산화탄소 흡착 성능을 연구하였다. Cu-Mn 함량 비율과 흡착조업조건에 따른 흡착능을 측정하여 최적 흡착조건을 구하였다.