• 제목/요약/키워드: adsorption properties

검색결과 1,269건 처리시간 0.027초

토양의 물리화학적 특성이 세슘 흡착에 미치는 영향 (Influence of Physicochemical Properties on Cesium Adsorption onto Soil)

  • 박상민;이제신;김영훈;이정선;백기태
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제22권1호
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    • pp.27-32
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    • 2017
  • Cesium (Cs) generated by nuclear accidents is one of the most hazardous radionuclides because of its gamma radiation and long half-life. Especially, when Cs is exposed on the soil environments, Cs is mainly adsorbed on the topsoil and is strongly combined with tiny soil particle including clay minerals. The adsorption of Cs onto soil can vary depending on various physicochemical properties of soil. In this study, the adsorption characteristics between soil and Cs were investigated according to various physicochemical properties of soil including organic matter contents, cation exchange capacity (CEC), soil particle size, and the types of clay minerals. Soil organic matter inhibited the adsorption of Cs onto the soil because organic matter was blocking the soil surface. In addition, it was estimated that the CEC of the soil influenced the adsorption of Cs onto the soil. Moreover, more Cs was adsorbed as the soil particles size decreased. It was estimated that Cs was mostly adsorbed onto the topsoil, this is related to the clay mineral. Therefore, soil organic matter, CEC, soil particle size, and clay minerals are considered the key factors that can influence the adsorption characteristics between soil and Cs.

Water Vapor Adsorption and Hydrogen Peroxide Decomposition on Date Pit Carbonization Products

  • Youssef, A.M.;El-Nabarawy, Th.;Ahmed, S.A. Sayed;Rashwan, W.E.
    • Carbon letters
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    • 제6권4호
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    • pp.227-233
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    • 2005
  • Carbonization products C1, C2, C3, C4 and C5 were prepared by the carbonization of date pit in limited air, at 500, 600, 700, 800 and $1000^{\circ}C$, respectively. C1-V-600, C3-V-600, C1-V-1000 and C3-V-1000 were prepared by thermal treatment of C1 and C3 under vacuum at 600 and $1000^{\circ}C$. The textural properties were determined from nitrogen adsorption at 77 K and from carbon dioxide adsorption at 298 K. The surface pH, the FTIR spectra and the acid and base neutralization capacities of some carbons were investigated. The amounts of surface oxygen were determined by out-gassing the carbon-oxygen groups on the surface as $CO_2$ and CO. The adsorption of water vapor at 308 K on C1, C2, C3 and C4 was measured and the decomposition of $H_2O_2$ at 308 K was also investigated on C1, C2, C3, C4 and C5. The surface area and the total pore volume decreased with the rise of the carbonization temperature from 500 to $1000^{\circ}C$. The adsorption of water vapor is independent on the textural properties, while it is related to the amount of acidic carbon-oxygen groups on the surface. The catalytic activity of $H_2O_2$ decomposition does not depend on the textural properties, but directly related to the amount of basic carbon-oxygen complexes out-gassed as CO, at high temperatures.

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소나무 및 참나무 백탄의 물성과 구리(II) 이온 흡착 효과 (Physicochemical Properties and Copper(II) Ion Adsorption Ability of Wood Charcoals)

  • 이오규;조태수
    • 임산에너지
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    • 제25권2호
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    • pp.55-63
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    • 2006
  • 전통 방식으로 제조되어 시중에 유통 중인 2종의 참나무 백탄과 2종의 소나무 백탄에 대한 물성과 수용액 상 구리(II) 이온 흡착 성질을 시험하였다. 물성시험 결과, 탄의 pH는 약 9.5-9.8로 시료 탄간의 차가 크지 않았다. 원소 조성에 있어서는, 4종 시료 탄의 탄소(C) 함량이 약 85-90%로 나타났으며 S사 소나무탄의 수소(H) 함량이 1.62%로 타 시료에 비해 3배가량 높았다. 4종 시료 탄의 요오드 흡착량과 비표면적 측정의 결과에서는, 소나무탄이 참나무탄 보다 높게 나타났다. 이들 시료 목탄의 수용액 내 구리(II) 이온 흡착율 측정 시험에서는, 목탄 시료의 처리양이 늘어날수록, 처리 시간이 길수록, 그리고 pH가 높을수록 높은 구리(II) 이온 흡착율을 나타냈다.

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Reduction of Phosphate Adsorption by Ion Competition with Silicate in Soil

  • Lee, Yong-Bok;Kim, Pil-Joo
    • 한국환경농학회지
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    • 제26권4호
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    • pp.286-296
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    • 2007
  • To increase phosphate (P) availability in soils, the efficiency of silicate (Si) in reducing P adsorption was investigated by competitive adsorption tests under changing conditions of pH, ion concentrations, and order of anion addition along with single adsorption properties of each ion at $20^{\circ}C$. In the single ion adsorption study, P and Si ions showed the opposite reaction patterns: phosphate adsorption decreased with increasing pH and attained adsorption maximum however, silicate adsorption increased with increasing pH without attaining adsorption maximum. Phosphorus and Si adsorption were influenced by pH in the range of 5.0 - 9.0 and the type and amount of P and Si concentration. Silicate added to soil before P or in a mixture with P significantly reduced P adsorption above pH 7.0; however, there was no significant Si-induced decreased in P adsorption at pH 5.0 when anions were added as mixture. The efficiency of Si in reducing P adsorption increased with increasing Si concentration and pH. The effect of P on Si adsorption was relatively small at pH 5.0 and no effect of P on silicate adsorption was observed at pH 9.0. The presence of Si strongly depressed P adsorption when Si was added before P compared to P and Si added as a mixture. These results suggest that application of Si may decrease P adsorption and increase the availability of P in soils. Furthermore, a Si source would be better to add before P application to enhance the availability of P in soils.

복합음이온 교환섬유의 플라스마 산화 처리한 NO의 흡착특성 (Adsorption Properties of Oxidized NO by Plasma Using Hybrid Anion-Exchange Fibers)

  • 조인희;강경석;황택성
    • 폴리머
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    • 제30권4호
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    • pp.291-297
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    • 2006
  • 본 연구에서는 아민화 polyolefin-g-GMA 복합음이온 교환섬유를 이용하여 플라스마 산화된 NO의 흡착특성을 고찰하였다. 플라스마 산화에 의한 $NO_2$ 전환율은 NO 200 ppm, 산소 10%, 유속 30 L/min 일 때 최대 49% 이었다. 또한 복합음이온 교환섬유의 $NO_2$ 흡착량은 함수율이 높을수록 증가하였고 함수율이 최대 1.5 g $H_2O/g$ IEF 이었으며, 복합음이온 교환섬유의 $NO_2$ 흡착은 10 분까지 빠르게 진행되었고 120 분에서 최대 80% 흡착되었다. 이온교환 용량은 함수율이 증가함에 따라 증가하였으며, 흡착컬럼 충전 비가 L/D=5에서 0.6 mmol/g IEF로 가장 높았다. 또한 이온교환 섬유의 흡착은 Langmuir 등온흡착 모델보다 Freundlich 등온흡착 모델에 가까웠으며, 다분자층에서의 흡착이 우세하게 발생한 것을 확인할 수 있었다.

흡착제의 흡착특성 규명을 위한 흡착모델의 적용성 평가(1)-흡착등온식을 이용한 평가 (Applicability of Theoretical Adsorption Models for Studies on Adsorption Properties of Adsorbents(1))

  • 나춘기;한무영;박현주
    • 대한환경공학회지
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    • 제33권8호
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    • pp.606-616
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    • 2011
  • 본 연구는 흡착제의 흡착특성을 이해하는데 이용되는 각종 흡착모델의 적용성을 평가하는데 목적이 있다. 이를 위해 상용의 음이온교환수지(PA-308)를 이용하여 $NO_3^-$에 대한 흡착특성을 회분식 실험을 통해 조사하였다. 흡착등온과 흡착속도 실험결과는 일반적으로 널리 이용되고 있는 다양한 흡착등온식과 반응속도식을 통해 모델화하였다. 흡착평형실험은 흡착등온식을 적용하는데 있어 실험조건이 미치는 영향을 확인하기 위해 흡착제의 투여량을 일정한 값으로 고정하고 흡착질의 농도변화에 따른 조건과 흡착질의 농도를 일정한 값으로 고정하고 흡착제의 투여량 변화에 따른 조건으로 나누어 수행하였다. 흡착질의 농도를 변화시키는 조건에서의 흡착평형은 Langmuir와 Freundlich 흡착등온식을 결합한 형태의 Sips 흡착등온식과 Redlich-Perterson 흡착등온식에 의해 수식화가 가능하였다. 한편, 흡착제의 무게를 변화시키는 조건에서의 흡착평형은 단층 흡착, 균일표면을 가정하는 Langmuir 흡착등온식과 잘 일치하는 경향을 보였다. 이상의 결과는 $NO_3^-$에 대한 음이온교환수지의 흡착 메커니즘이 흡착실험 조건에 의해 달라질 수 있음을 시사한다.

EDCs/PhACs의 단일,복합 조건에서의 GAC에 대한 흡착 연구 (Adsorption of selected endocrine disrupting compounds (EDCs)/pharmaceutical active compounds (PhACs) onto granular activated carbon (GAC) : effect of single and multiple solutes)

  • 정찬일;손주영;윤여민;오재일
    • 상하수도학회지
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    • 제28권2호
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    • pp.235-248
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    • 2014
  • The widespread occurrence of dissolved endocrine disrupting compounds(EDCs) and pharmaceutical active compounds(PhACs) in water sources is of concern due to their adverse effects. To remove these chemicals, adsorption of EDCs/PhACs on granular activated carbon(GAC) was investigated, and bisphenol A, carbamazepine, diclofenac, ibuprofen, and sulfamethoxazole were selected as commonly occurring EDCs/PhACs in the aquatic environment. Various adsorption isotherms were applied to evaluate compatability with each adsorption in the condition of single-solute. Removal difference between individual and competitive adsorption were investigated from the physicochemical properties of each adsorbate. Hydrophobicity interaction was the main adsorption mechanism in the single-solute adsorption with order of maximum adsorption capacity as bisphenol A > carbamazepine > sulfamethoxazole > diclofenac > ibuprofen, while both hydrophobicity and molecular size play significant roles in competitive adsorption. Adsorption kinetic was also controled by hydrophobicity of each adsorbate resulting in higher hydrophobicity allowed faster adsorption on available adsorption site on GAC. EDCs/PhACs adsorption on GAC was determined as an endothermic reaction resulting in better adsorption at higher temperature ($40^{\circ}C$) than lower temperature ($10^{\circ}C$).

흡착질의 증기압이 흡착에 미치는 영향 (Effect of Vapor Pressure of Adsorbate on Adsorption Phenomena)

  • 김상원;권준호;강정화;송승구
    • 한국환경과학회지
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    • 제17권1호
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    • pp.67-75
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    • 2008
  • Adsorption process is largely influenced by pore structures of adsorbents and physical properties of adsorbates and adsorbents. The previous studies of this laboratory was focused on the role of pore structures of adsorbents. And we found some pores of adsorbates which have larger pore diameters than the diameter of adsorbate are filled with easily. In this study the effects of physical and chemical properties of adsorbates and adsorbents, such as pore size distribution, vapor pressure on adsorption were investigated more thoroughly at the concentration of adsorbate of 1000 ppm. The adsorption in the pore ranges of $2{\sim}4$ times of adsorbates's diameter could be explained by space filling concept. But there was some condensation phenomena at larger pore ranges. The errors between the adsorbed amount of non-polar adsorbates and the calculated amounts by considering factors were found to be 44.46%, positively, and -142%, negatively. When vapor pressure is considered, the errors between the adsorbed amount of non-polar adsorbates and the calculated amounts were in the range of $1.69%{\sim}32.25%$ positively, and negatively $-1.08%{\sim}-63.10%$.

Elemental Mercury Adsorption Behaviors of Chemically Modified Activated Carbons

  • Kim, Byung-Joo;Bae, Kyong-Min;An, Kay-Hyeok;Park, Soo-Jin
    • Bulletin of the Korean Chemical Society
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    • 제32권4호
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    • pp.1321-1326
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    • 2011
  • In this work, the effects of different surface functional groups on the elemental mercury adsorption of porous carbons modified by chemical treatments were investigated. The surface properties of the treated carbons were observed by Boehm's titration and X-ray photoelectron spectroscopy (XPS). It was found that the textural properties, including specific surface area and pore structures, slightly decreased after the treatments, while the oxygen content of the ACs was predominantly enhanced. Elemental mercury adsorption behaviors of the acidtreated ACs were found to be four or three times better than those of non-treated ACs or base-treated ACs, respectively. This result indicates that the different compositions of surface functional groups can lead to the high elemental mercury adsorption capacity of the ACs. In case of the acid-treated ACs, the $R_{C=O}/R_{C-O}$ and $R_{COOH}/R_{C-O}$ showed higher values than those of other samples, indicating that there is a considerable relationship between mercury adsorption and surface functional groups on the ACs.

Kinetics and Thermodynamic Properties Related to the Adsorption of Copper and Zinc onto Zeolite Synthesized from Coal Fly Ash

  • Lee, Chang-Han;Ambrosia, Matthew Stanley
    • 한국환경과학회지
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    • 제22권10호
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    • pp.1327-1335
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    • 2013
  • Na-A zeolite (Z-Cl) was synthesized from coal fly ash, which is a byproduct of coal combustion for the generation of electricity. The adsorption of $Cu^{2+}$ and $Zn^{2+}ions$ onto Z-C1 was investigated via batch tests over a range of temperatures (303.15 to 323.15 K). The resultant experimental equilibrium data were compared to theoretical values calculated using model equations. With these results, the kinetics and equilibrium parameters of adsorption were calculated using Lagergren and Langmuir-Freundlich models. The adsorption kinetics revealed that the pseudo second-order kinetic mechanism is predominant. The maximum adsorption capacity ($q_{max}$) values were 139.0-197.9 mg $Zn^{2+}$/g and 75.0-105.1 mg $Cu^{2+}/g$. Calculation of the thermodynamic properties revealed that the absorption reactions for both $Cu^{2+}$ and $Zn^{2+}$ were spontaneous and endothermic. Collectively, these results suggest that the synthesized zeolite, Z-C1, can potentially be used as an adsorbent for metal ion recovery during the treatment of industrial wastewater at high temperatures.