• Bulletin of the Korean Chemical Society
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• 제18권11호
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• pp.1175-1179
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• 1997

The adsorption of oxygen on ZnO was monitored by measuring the capacitance of two contacting crystals which have depletion layers originated from the interaction between oxygen and ZnO at 298 K-473 K. An admission of oxygen to the sample induced an irreversible increase in the depth and the amount of adsorbed oxygen was less than 0.001 monolayer in the experimental condition. The relation between pressure of oxygen and variation of the depth was tested from the view point of Langmuir or Freundlich isotherm. Using Hall effect measurement and kinetic experiment, a model equation on the adsorption process was proposed. From the results, it was suggested that oxygen adsorption depended on the rate of electron transfer from ZnO to oxygen while the amount of adsorbed oxygen was kinetically restricted by the height of surface potential barrier.

• 한국토양비료학회지
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• 제10권1호
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• pp.1-6
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• 1977

화산회토(火山灰土), 특이산성토(特異酸性土), 퇴화염토등(退化鹽土等) 15개토양(個土壤)에 대(對)하여 $NH_4H_2PO_4$를 사용(使用), 암모늄의 Langmuir 등온흡착(等溫吸着)을 본 결과(結果)는 다음과 같다. 1. 암모니움 Langmuir 흡착최대량(吸着最大量)(LAMA)은 2.4me/100g에서 12.3이었고 평균(平均)은 5.3이었으며 30, 60ppm 또는 40과 80ppm의 두 농도(濃度)에서 측정(測定)할 수 있다. 2. LAMA는 토양(土壤)에 따라 두개가 존재하였으며 LAMA의 차이보다 흡착상수(결합에너지)의 차이가 더욱 컸다. 3. LAMA는 CEC의 9.4%에서 72%까지 해당되며 그 평균(平均)은 47%였고 토양(土壤)의 점토함량(粘土含量), CEC, pH, 유기물(有機物), 염기포화도(鹽基飽和度), 인산(燐酸), Ca, Mg, K, Na 어느 것과도 분명(分明)한 경향(傾向)을 보이지 아니하였다. 4. LAMA는 화산회토(火山灰土)를 제외(除外)하면 200ppm에서의 흡착량(吸着量)과 고도(高度)의 유의상관(有意相關)(r=0.951, 1% 유의)을 보이므로 200ppm 단일농도(單一濃度)에서 측정가능(測定可能)하다. 화산회토(火山灰土)는 암모늄 흡착양상(吸着樣相)에 의(依)하여 2군(群)으로 분류(分類)될 수 있다. 5. 암모늄의 흡착양식(吸着樣式)은 토양철(土壤鐵)이나 Al과 동반음(同伴陰) ion이 결합(結合)하고 이 음(陰) ion에 암모늄이 흡착(吸着)하는 것으로 추론(推論)되며 Langmuir 등온흡착모형(等溫吸着模型)의 포장토양(圃場土壤)에의 적용(適用)에 관(關)하여 검토(檢討)하였다.

• Korean Chemical Engineering Research
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• 제47권3호
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• pp.321-326
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• 2009

간단한 기체농도 측정장치를 제안하여, 혼합기체를 분리하는 흡착공정에서 성능을 실험적으로 조사하였다. 측정센서는 수정진동자의 전극에 고체의 흡착제를 도포하여 유효성분을 선택적으로 분리하게 하여 농도를 측정하였다. 센서용 흡착제는 마이크로 입자의 카본 크라이오젤(Micro-Particle Carbon(MCC))을 사용하였고, 공기와 i-부탄의 혼합기체를 대상으로 대나무 활성탄을 채운 칼럼에서 분리하는 공정을 사용하였다. 칼럼의 입구와 출구에 측정시스템을 각각 장치하고 i-부탄의 농도를 측정하였다. 입구와 출구의 실제농도를 GC로 측정한 결과와 측정한 수정진동자의 공진주파수를 비교하여 제안한 측정시스템이 유용하게 농도를 측정할 수 있음을 보였다. 실험을 통하여 제안하는 시스템이 비교적 간단한 장치로, 실시간 인라인 측정이 가능함을 입증하여 실제공정에 유용하게 활용할 수 있음을 보였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 제35회 춘계학술대회
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• pp.120-129
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• 2002

New method and device for the on-line measurement of soot concentration in a diesel engine oil are proposed, where the measurement principle is based mainly on attenuated internal total reflection. Various laboratory tests of the detector were performed mainly with carbon black particles of different contamination levels. It was found that the proposed detector could be well used to monitor oil deterioration due to soot contamination. Operational range of the detector was found from 0 to 5 mass percentage of soot content. Test results with water and fuel dilution showed that these effects were not remarkable. However, adsorption of carbon black particles to a measurement surface was considered to be a critical problem in the new detector. Effects of particle deposition onto the interface was experimentally evaluated with the oil temperature and turbulence and discussed throughout this work.

• 분석과학
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• 제11권4호
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• pp.254-259
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• 1998

참나무톱밥에 의한 6가크롬의 흡착과 환원특성이 연구되었다. 용액의 pH를 변화하면서 톱밥의 Cr(VI)에 대한 분포계수($K_d$)와 흡착용량을 측정하여 최적조건을 발견하였다. 결과, pH 2.0이 최적조건이었다. 왜냐하면 이 pH에서 Cr(VI)의 $K_d$는 최대이고 Cr(III)로의 환원량은 최소이었기 때문이다. 이러한 참나무 톱밥의 특성을 이용하여 공장폐수중 Cr(VI)의 제거방법도 연구하였다.

• Advances in environmental research
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• 제7권1호
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• pp.53-71
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• 2018

Waste glass disposal causes environmental problems in the cities. To find a suitable green environmental solution for this problem low cost adsorbent in this study was prepared from waste glass. An effective new green adsorbent was synthesized by hydrothermal treatment of waste glass (WG), followed by acidic activation of its surface by HCl (WGP). The prepared adsorbent was characterized by scanning electron microscopy (SEM), X-ray fluorescence (XRF), X-ray diffraction (XRD), and BET surface measurement. The developed adsorbent was used for the removal of heavy metals (Cd, Cu, Fe, Pb and Zn) from well water. Batch experiments were conducted to test the ability of the prepared adsorbent for the removal of Cd, Cu, Fe, Pb and Zn from well water. The experiments of the heavy metals adsorption by adsorbent (WGP) were performed at different metal ion concentrations, solution pH, adsorbent dosage and contact time. The Langmuir and Freundlich adsorption isotherms and kinetic models were used to verify the adsorption performance. The results indicated high removal efficiencies (99-100%) for all the studied heavy metals at pH 7 at constant contact time of 2 h. The data obtained from adsorption isotherms of metal ions at different time fitted well to linear form of the Langmuir sorption equation, and pseudo-second-order kinetic model. Application of the resulted conditions on well water demonstrated that the modified waste glass adsorbent successfully adsorbed heavy metals (Cd, Cu, Fe, Pb and Zn) from well water.

• Tribology and Lubricants
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• 제20권6호
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• pp.343-349
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• 2004

The adsorption of soot particles onto a sensor surface of the engine soot detector posses a critical problem in the measurement. In order to prevent the optical rod surface from soot contamination, various functional coatings and flow-induced cleaning were applied to the surface in this work. For surface coatings, various materials of self-assembled monolayers (SAM) such as OTS (octadecyltrichlorosilane), PFDTES (perfluorodecyl-triethoxysilane) and PFDTMS (perfluorodecyltrimethoxysilane) were coated on the optical rod surface ,which have different characteristics in both hydrophobicity and oleophobicity. These coatings were tested with soot content varying from $0\%\;to\;3wt\%$ and oil temperature from 20 to $70^{\circ}C$. Test results showed that surface coatings were not effective for preventing the adsorption of soot panicles on the surface of optical rod. It was thought that these coatings provided the surface with additional attractive surface forces. However, it was found that adsorption of soot particles onto a sensor surface was minimized by flow-induced cleaning. This effect was tested with varying the flow velocity.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2394-2401
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• 2020

Octadecylamine is an effective film-forming amine that protects carbon steel from corrosion. In the present study, the effect of octadecylamine concentration on adsorption on a carbon steel surface was investigated in anaerobic alkaline solution by using SEM/EDS, TEM and the Materials Studio simulation techniques. TEM morphology observation and EDS elemental detection determine the thicknesses of octadecylamine film on a carbon steel surface, which are confirmed by the in-situ electrochemical impedance spectroscopy measurement and resistance calculation. The Materials Studio simulation reveals the number of octadecylamine film layers at different concentrations. Results obtained in this study indicate that adsorption of octadecylamine film on carbon steel proceeds with the multi-layer adsorption mechanism.

• Bulletin of the Korean Chemical Society
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• 제13권3호
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• pp.332-334
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• 1992

An accurate method of density measurement is proposed. The method makes use of a gravimetric adsorption apparatus and is quite suitable for powdery and porous solid samples. The sample volume is determined by measuring its buoyancy with microbalance and the mass is measured in vacuum in the absence of buoyancy effect. Densities of inorganic compounds, such as alumina and perovskite, and some organic compounds are determined with the proposed method, and the results are compared with the values either determined with conventional methods or obtained from literatures.

• Bulletin of the Korean Chemical Society
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• 제8권3호
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• pp.150-155
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• 1987

A new method of measurement of pore volume distribution in a porous material by adsorption of gases is proposed. In the newly proposed method the use of spherical molecules with relatively large molecular weight as adsorbates is strongly recommended to eliminate the troubles caused by stereospecificity and low boiling point of widely used $N_2$. It is also claimed that the universal t-curves that have been widely used since proposed by de Boer et al. must be replaced by the flat-surface isotherms that can be derived from the theory proposed by Chang et al. The results of analysis of pore volume distribution based on the method described in this paper are found to be reasonable and satisfactory.