• 한국세라믹학회지
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• 제37권6호
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• pp.517-523
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• 2000

Effect of catalysts, which was catalyzed by acid(HCl and HNO3) and base(NH4OH), on characteristics of the mullite powders prepared by sol-gel methdo wa sinvestigated by XRD, TGA, SEm AND BET. As a result, weight loss as a function of catalysts was in order of HCl=32.6%>HNO3=25.44%>Non=24.0%>NH4OH=22.5%. The mullite powder dried at 100$^{\circ}C$ appeared spherical shape in acid catalyst and different shape in base catalyst, but sintering powder at 1400$^{\circ}C$ appeared very fine particle of 0.05∼0.1$\mu\textrm{m}$ regardless of catalysts. In all cae, the pore quantity, which was capable to adsoprtion, was decreased with increasing temperature. In base catalyst, no change of special surface area in mullite appeared.

• 상하수도학회지
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• 제25권6호
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• pp.917-922
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• 2011

Adsorption characteristics of boron on activated carbon was investigated in order to evaluate the use of activated carbon for the removal of boron in desalination processes using SWRO. Boron was removed ranging from 54~60% when the concentration of activated carbon was 1,000 mg/L in 6 hours under the initial boron concentration of 5 mg/L. The removal of boron increased by 20~22% with the increase of pH from 5 to 9. Organic matter had adverse effect on the adsorption of boron on activated carbon. Boron removal decreased by 10-12% when EDTA was added at 1 mg/L under 5 mg/L of boron and 200mg/L of activated carbon. In this results, activated carbon would be a good candidate for a pretreatment of desalination processes by SWRO from the view of mitigating the feed boron concentration to RO and meeting the effluent boron concentration without post-treatment after RO.

• 한국환경과학회지
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• 제21권6호
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• pp.705-711
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• 2012

Adsorption experiment of carbon dioxide was performed on MCM41 silica with a 30 wt.% EDA(ethylenediamine) loading at different $CO_2$ inlet concentration and various adsorption temperature. The surface characteristics of $CO_2$ capturing agent were carried out using BET analysis, X-ray diffraction and FT-IR. The results of BET showed 781 $m^2/g$ for MCM41 and 464 $m^2/g$ for EDA/MCM41. X-ray diffraction results reveled typical hexagonal pore system. The higher sorption capacity of EDA/MCM41 was about 80 $mg_{CO2}/g_{sorbent}$ with 50% $CO_2$ inlet concentration and 303 K adsorption temperature. The isosteric heat of adsorption in 303-353 K ranged from -25.47 to -28.24 KJ/mole for EDA/MCM41, which indicates $CO_2$-EDA/MCM41 interaction with exothermic adsorption process. Finally, the performance of EDA/MCM41 in 10 consecutive sorption-desorption runs was a stable with only a minor drop in its sorption capacity.

• 분석과학
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• 제13권1호
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• pp.89-95
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• 2000

식물섬유, 합성섬유 및 혼합섬유를 원료로 하여 3등급의 활성탄소섬유를 제조하고 미세기공 및 세공특성을 검토하였다. 제조한 활성탄소섬유의 흡착등온선은 모두 $20{\AA}$ 이하의 기공크기를 나타내는 Type I을 보였으며 미세기공 직경은 $5.6{\pm}0.3{\AA}$ 이내에서 최대 분포를 나타냈다. 활성탄소섬유의 질소 또는 아르곤 흡착에 의한 비표면적($S_{BET}$), 산화율, 액상 요오드흡착에 대한 상관 관계를 조사한 결과 비표면적이 $1600m^2g^{-1}$까지는 비표면적의 증가와 액상 요오드흡착량이 직선 관계를 나타냈으나 그 이상의 비표면적에서는 요오드 흡착량이 낮은 결과를 보이고, 비표면적이 증가할수록 제품의 burn-off가 크게 나타났다.

• 청정기술
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• 제19권1호
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• pp.65-72
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• 2013

본 연구에서는 중형 기공성 실리카 담체인 MCM-41과 SBA-15를 활용하여 팔라듐과 구리를 담지한 후, 제조 촉매의 수중 질산성 질소 저감 반응 활성을 평가하였다. 순수 수소 공급 반응 조건에서, 질산성 질소의 농도는 반응 시간에 따라 점차 저감되었지만, 반응기 내부에 높게 형성된 pH로 인해 질소의 선택도가 매우 낮은 문제점이 발견되었다. 이를 해결하기 위해 이산화탄소를 수소와 함께 공급하여 pH의 안정화를 도모하였고, 질소 선택도를 40% 가량 증가시켰다. 상기 두 반응 조건에서 모두 Pd-Cu/MCM-41가 Pd-Cu/SBA-15보다 높은 활성을 나타냈다. 이와 같이 수중 질산성 질소 저감 반응의 활성에 차이를 보이는 두 촉매에 대하여, 질소 흡-탈착, XRD, $H_2$-TPR, XPS 등과 같은 특성 분석을 수행하여 제조 촉매의 구조와 물성이 반응활성에 미치는 영향을 검토해보았다.