• 제목/요약/키워드: molecular adsorption

검색결과 433건 처리시간 0.021초

Adsorption of Phenols onto Chemically-Activated Carbons Developed from Wild Cherry Stones

  • Alaya, M.N.;Youssef, A.M.;Karman, M.;Abd El-Aal, H.E.
    • Carbon letters
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    • 제7권3호
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    • pp.188-195
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    • 2006
  • Phosphoric acid-activated carbon WP's and zinc chloride-activated carbons WZ's were developed from wild cherry stones. The textural properties of the activated carbons were determined from nitrogen adsorption data at 77 K and the chemistry of the carbon surface, i.e. the surface carbon-oxygen groups (type and amount) was determined from the base and acid neutralization capacities (Boehm method). The adsorption of phenol, p-nitrophenol, p-chlorophenol, dinitrophenol and dichlorophenol was followed at 298 K. The activated carbons obtained were characterized by high surface area and large pore volumes as well as by high surface concentration of C-O groups. The investigated carbons exhibited high adsorption capacities towards phenols with these capacities increased with the increase of molecular weight and the decrease of the solubility of phenol in water. However, no general relationship could be observed between the adsorption capacities of carbons and any of their textural parameters or their surface chemistry. This may be attributed to the many factors controlling phenol adsorption and the different types and mechanisms of adsorption involved.

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흑연 표면위의 p-크실렌과 벤젠의 흡착 (Adsorption of p-Xylene and Benzene on Graphite)

  • 장세헌;이순보;김윤수;안운선
    • 대한화학회지
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    • 제20권5호
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    • pp.351-357
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    • 1976
  • 진공미량저울을 써서 Spheron 6 (흑연카아본블랙)와 Alucer M.A. (Alumina) 위에서의 벤젠과 p-크실렌의 흡착등온곡선을 여러 온도에서 얻었다. 이로부터 이 두 흡착질의 흡착분자단면적이 온도에 어떻게 의존하는가를 알아 보았다. 흑연표면에서 p-크실렌은 $19^{circ}C$이하에서 촘촘하게 쌓인 편재흡착을 하고 $19.2^{circ}C$이상의 높은 온도에서는 제한된 회전을 하는 편재흡착을 한다. 이것으로 미루어 보아 벤젠, 및 간단한 벤젠유도체들도 낮은 온도에서는 촘촘하게 쌓인 편재흡착을 하고 높은 온도에서는 제한된 회전을 하는 편재흡착을 일으킨다고 생각된다. 한편 Alucer M.A. 표면에서는 이들 흡착질 분자의 흡착단면적이 온도증가에 따라 점차적으로 증가하여, 이들 흡착질 분자가 편재화되어 있지 않음을 나타내었다.

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가스 흡착 및 분리공정용 활성탄소와 탄소분자체의 제조 및 응용 (Manufacturing and Application of Activated Carbon and Carbon Molecular Sieves in Gas Adsorption and Separation Processes)

  • 정서경;하성민;이영석
    • 공업화학
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    • 제33권5호
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    • pp.488-495
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    • 2022
  • 온실가스의 회수 및 분리를 위한 다공성 물질로 활성탄소와 탄소분자체가 주목을 받아왔다. 균일한 기공을 가지는 탄소분자체는 특정 가스를 선택적으로 흡착할 수 있기 때문에 가스의 포집 및 분리에 사용되고 있다. 탄소분자체의 성능은 세공의 크기 및 균일성에 따라 좌우되는데, 이러한 탄소분자체의 미세 기공 제어를 위하여 표면을 일정한 두께로 코팅할 수 있는 화학기상증착법이 널리 사용 되고 있다. 이 화학기상증착법은 탄소분자체 제조 시 기공의 크기를 제어하는데 사용될 수 있으나, 그 실험 변수가 다양하기 때문에 이에 대한 최적화가 필요하다. 따라서, 본 총설에서는 가스 흡착 및 분리공정용 활성탄소와 탄소분자체를 제조하기 위하여 여러 가지 활성화 공정, 화학기상증착법과 표면처리 등에 의한 기공 제어 기술들을 중심으로 다루고자 한다.

열수 및 알칼리 용액을 이용하여 국산 목재 칩으로부터 선추출한 헤미셀룰로오스의 특성과 이에 따른 수초지 물성 변화 (Characteristics of pre-extracted hemicelluloses from Korean mixed wood by hot water and alkali solution and its effect on handsheet properties)

  • 서동일;이상훈;심규정;이학래;윤혜정
    • 펄프종이기술
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    • 제43권5호
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    • pp.60-67
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    • 2011
  • Hemicelluloses pre-extracted from Korean mixed wood chip were investigated as a wet-end additive. Hemicelluloses dissolved in hot water and alkali solution were isolated by ethyl alcohol precipitation from pre-extractives. They showed molecular weight of 9,000 ~ 27,000 g/mol as revealed by size exclusion chromatography. The reduction of molecular weight through hot water extraction was caused by autohydrolysis. Chemical composition of the hemicelluloses were analyzed with high-performance liquid chromatography and UV-Vis spectroscopy. As the surface charge of isolated hemicelluloses were negative, the adsorption of hemicelluloses onto softwood unbleached kraft pulp fiber was promoted by poly-DADMAC. The physical properties of handsheets increased as the molecular weight of hemicellulose increased. On the other hands, the optical property decreased with hemicellulose adsorption.

Comparative evaluation of the biological properties of fibrin for bone regeneration

  • Oh, Joung-Hwan;Kim, Hye-Jin;Kim, Tae-Il;Woo, Kyung Mi
    • BMB Reports
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    • 제47권2호
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    • pp.110-114
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    • 2014
  • Fibrin is a natural provisional matrix found in wound healing, while type I collagen is a major organic component of bone matrix. Despite the frequent use of fibrin and type I collagen in bone regenerative approaches, their comparative efficacies have not yet been evaluated. In the present study, we compared the effects of fibrin and collagen on the proliferation and differentiation of osteoblasts and protein adsorption. Compared to collagen, fibrin adsorbed approximately 6.7 times more serum fibronectin. Moreover, fibrin allowed the proliferation of larger MC3T3-E1 pre-osteoblasts, especially at a low cell density. Fibrin promoted osteoblast differentiation at higher levels than collagen, as confirmed by Runx2 expression and transcriptional activity, alkaline phosphatase activity, and calcium deposition. The results of the present study suggest that fibrin is superior to collagen in the support of bone regeneration.