• Title, Summary, Keyword: Bentonite

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Fabrication of EPDM Rubber/Organo-bentonite Composites: Influence of Hydrochloric Acid on the Characteristics of Modified Bentonite and Final Products (EPDM 고무/유기 벤토나이트 복합체의 제조: 개질된 벤토나이트와 최종 생성물의 특성에 대한 염산의 영향)

  • Ge, Xin;Li, Mei-Chun;Cho, Ur Ryong
    • Polymer Korea
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    • v.38 no.1
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    • pp.62-68
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    • 2014
  • To improve the compatibility of bentonite with rubber matrix, organo-modified bentonite was synthesized with a silane coupling agent, [3-(2-aminoethylamino)propyl]trimethoxysilane (AEAPTMS) in the suspension of bentonite. The structure and characteristics of organo-modified bentonite were investigated using FTIR-spectroscopy, thermogravimetric analysis (TGA) and X-ray diffraction (XRD). Ethylene-propylene-diene monomer (EPDM) rubber/organo-bentonite composites were compounded by a two-roll mill. The vulcanization and mechanical properties were studied. Results showed that the concentration of hydrochloric acid and $H_2O$ in the synthesis had significant influence on the modification of bentonite, which further contributed to the properties of the composites. Filled with 20 phr modified bentonite, the tensile strength and elongation at break of the rubber increased from 1.95 to 4.8 MPa and 300% to 500%, respectively.

Penetration of Compacted Bentonite into the Discontinuity in the Excavation Damaged Zone of Deposition Hole in the Geological Repository (심층처분장 처분공 주변 굴착손상영역에 존재하는 불연속면으로의 압축 벤토나이트 침투)

  • Lee, Changsoo;Cho, Won-Jin;Kim, Jin-Seop;Kim, Geon-Young
    • Tunnel and Underground Space
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    • v.30 no.3
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    • pp.193-213
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    • 2020
  • A mathematical model to simulate more realistically the penetration of compacted bentonite buffer installed in the deposition hole into the discontinuity in the excavation damaged zone formed at the inner wall of the deposition hole in the geological repository for spent fuel is developed. In this model, the penetration of compacted bentonite is assumed to be the flow of Bingham fluid through the parallel planar rock fracture. The penetration of compacted bentonite is analyzed using the developed model. The results show that the maximum penetration depth of compacted bentonite into the rock fracture is proportioned to the swelling pressure of saturated compacted bentonite and the aperture of rock fracture. However, it is in inverse proportion to the yield strength of compacted bentonite. The viscosity of compacted bentonite dominates the penetration rate of compacted bentonite, but has no influence to the maximum penetration depth.

Physicochemical Adsorption Characteristics of MTBE and Cadmium on Clay Minerals (점토광물에 대한 MTBE와 카드뮴의 물리화학적 흡착 특성)

  • Lim, Nam-Ho;Seo, Hyung-Joon;Kim, Chang-Gyun
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.3
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    • pp.231-239
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    • 2005
  • This study was performed to investigate adsorption characteristics of MTBE and Cd depending upon types of clay minerals md their physicochemical properties. The adsorption characteristics were examined by batch adsorption test on various experimental parameters such as adsorption time, ratio of solution to soil, concentration of contaminants, content of organic matter, pH, and zeta potential. The adsorption efficiency of MTBE or Cd for three types of clays decreased in response to the increase of the ratio of solution to soil whereas their adsorbed amounts increased. MTBE was greatly adsorbed in the decreasing order of vermiculite, bentonite, and CTAB-bentonite while Cd was adsorbed in the decreasing order of bentonite, vermiculite, and CTA-bentonite. An equilibrium isotherm for MTBE was well fitted to Freundlich plotting whereas that for Cd was closely corresponded to Langmuir isotherm. The adsorbed amount of MTBE on bentonite and vermiculite showed the maximum at 1% and 5% of humic acid, thereafter diminished while the adsorbed amount of MTBE on CTAB-bentonite increased in proportion to humic acid. Conversely, the adsorbed amount of Cd on the addition of humic acid continued to increase regardless of types of adsorbents. For all types of adsorbents, adsorbed quantity and adsorption efficiency of Cd have been coincidently increased at pH 8 and they were further enhanced at pH 10 showing 90% adsorption efficiency. Upon pH rose, the zeta potential on each adsorbent began to decrease, while increasing Cd concentration led to decline of zeta potential, which in turn ascribed to lowering dispersion stability that could consequently enhance adsorption capability.

A Study on Fatty Acid Profiles of Eggs in Older Laying Hens fed Diets Supplemented with Bentonite (벤토나이트를 산란노계 사료에 첨가시 계란의 지방산조성에 관한 연구)

  • Choi, In Hag
    • Journal of Environmental Science International
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    • v.27 no.5
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    • pp.341-344
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    • 2018
  • This study was conducted to determine the effects of dietary bentonite supplementation on the fatty acid profiles of eggs in older laying hens. A total of 90 Hy-line Brown layers, 74 weeks of age, were confined in 6 wire cages and then assigned randomly to two groups to receive one of the two diets (3 replicates of 15 older layers each) containing 0 and 0.2% bentonite for 4 weeks. After the 4-week feeding trial, no remarkable differences in individual fatty acid, saturated fatty acid (SFA), unsaturated fatty acid (UFA), and mono unsaturated fatty acid (MUFA) levels were found. However, linoleic acid, docosahexaenoic acid, and poly unsaturated fatty acid (PUFA) and UFA/SFA ratio were influenced by 0.2% bentonite. In conclusion, supplementation with 0.2% bentonite improved the profiles of PUFA more than those of SFA, UFA, and MUFA inthe eggs of the older laying hens.

HDTMA-Bentonite로부터 페놀류 화합물의 경쟁탈착

  • 신원식;김영규;송동익
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • pp.15-18
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    • 2001
  • Sorption/desorption studies were conducted to determine sorption/desorption characteristics of phenolic compounds (phenol and 4-chlorophenol) in organically modified natural bentonite. The cationic exchange capacity (CEC) of bentonite was exchanged with a cationic surfactant, hexadecyltrimethylammonium (HDTMA), to enhance the removal capacity of organic phenol contaminants dissolved in aqueous solution. This modification produces a change of the surface property of bentonite from hydrophilic to organophilic. The single-solute and bi-solute competitive adsorptions were performed In batch mode to investigate the removal of two toxic organic Phenols, chlorophenol and 4-chlorophenol on the HDTMA-bentonite. The adsorption affinity of the 4-chlorophenol was higher than phenol due to higher octanol:water partition coefficient (Kow). The single-solute and bi-solute competitive desorptions were also performed investigate the competitive desorption of the phenolic compounds from HDTMA-bentonite. Freundlich model was used to analyze the single-solute adsorption/desorption results, while the IAST model predicted the hi-solute adsorption/desorption equilibria. The IAST model well predicted hi-solute competitive adsorption/desorption behaviors.

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The Purification Characteristics of Reactive Soil-Bentonite Landfill Liner (혼합반응 차수재의 오염정화특성)

  • 김학문
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.4 no.4
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    • pp.398-403
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    • 2003
  • The purpose of this paper is to investigate purification characteristic of soil-bentonite landfill liner and to develop a desirable liner system. In order to clarify the purification characteristics, high pressure column tests using soil-bentonite, reactive soil-bentonite and reactive bentomat were carried out in the presence of water and leachate. The test results indicated that the significant amount of NH$_3$-N, Pb and Cu was removed through the reactive soil-bentonite liner system.

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Improvement of Adsorbability of Methylene Blue on Bentonite Treated with Electrolyte Solution (Bentonite의 전각질수용액 처리에 의한 Methylene Blue 흡착성 개선)

  • 신병식;김면섭
    • Journal of the Korean Ceramic Society
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    • v.11 no.2
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    • pp.11-16
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    • 1974
  • Korean Yung-il bentonite was treated with potassium chloride, zinc chloride, calcium chloride, ferric chloride, or chromic chloride solutions respectively varying their concentration, treating temperature and treating time. The adsorbabilities of methylene blue on these pretreated bentonite were investigated. In the case of treatment with potassium chloride solution, the improvement of the adsorbahility of methylene blue on the products was observed, and in the best result the adsorbability was 1.6 times better than that on the original bentonite. With zinc chloride solution, the optimum adsorbability was a value of 1.7 times better than that on the original bentonite. With ferric chloride, chromic chloride or calcium chloride solution, slight improvement of the adsorbability was observed.

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A Study on the Swelling Property of Bentonite Mat under Salt Water Condition (담수환경하에 노출된 일반 벤토나이트 매트재의 팽윤성능 평가)

  • 양승도;김영삼;유재강;오상근
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.81-84
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    • 2002
  • Recently Bentonite mat is applied various structure : External waterproofing for underground structure, A reclaimed land, Artificial lake, Large-scaled civil structure, etc. With these various structure environment, water quality for application of Bentonite Mat affects watertightness. Specially spot with a large quantity of Chloride ion like salt water, degree of watertightness revelation is evaluated and applied. In this study, it is a main goal to investigate watertightness of Bentonite Mat with distilled water and salt water dissolved chloride ion Contents 0.88%. The result of this paper is as follows. 1) Water permeability coefficient of Bentonite Mat : distilled water(1.21$\times$10$^{-9}$cm/sec), salt water(3.12$\times$10$^{-7}$cm/sec). 2) Variation of thickness : distilled water(187%), salt water(108%). 3) Swelling ratio : distilled water(1500%), salt water(350%).

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A Case Study on the Quality Control of Soil-Bentonite Admixed Liner (흙-벤토나이트 혼합 차수재의 품질관리 사례연구)

  • 정하익;이용수;홍승서;정길수;이회준
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.497-504
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    • 1999
  • This study presents the physical and engineering characteristics of soil-bentonite admixed liner in I landfill. Main focus was the hydraulic conductivity of compacted soil-bentonite admixed and mechanisms governing low permeable properties of the admixed liner. Laboratory and field tests such as compaction, hydraulic conductivity, density, water content for the soil-bentonite admixed liner were carried out. Quality control criteria for the best construction of the soil-bentonite admixed liner was suggested through laboratory and field test results.

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Hydraulic Conductivity of Bentonite-Sand Mixture for a Potential Backfill Material for a High-level Radioactive Waste Repository

  • Cho, Won-Jin;Lee, Jae-Owan;Kang, Chul-Hyung
    • Nuclear Engineering and Technology
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    • v.32 no.5
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    • pp.495-503
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    • 2000
  • The hydraulic conductivities in the bentonite-sand mixtures with high density were measured, and the effects of sand content and dry density on the hydraulic conductivity were investigated. The hydraulic conductivities of the bentonite-sand mixtures with a dry density of 1.6 Mg/㎥ and 1.8 Mg/㎥ are less than 10$^{-11}$ m/s when the sand content is not higher than 70 wt%. However at the sand content of 90 wt%, the hydraulic conductivity increases rapidly At the same dry density, the logarithm of hydraulic conductivity increases linearly with increasing sand content. The hydraulic conductivity of the bentonite-sand mixture can be explained by the concept of effective clay dry density, and using this concept, the hydraulic conductivities for the mixtures with various sand contents and dry densities can be estimated.

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