• Title, Summary, Keyword: Bentonite

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Adsorption of Heavy Metals on Organobentonite (유기 벤토나이트에 의한 중금속 흡착특성)

  • 유지영;최재영;박재우
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • pp.168-171
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    • 2001
  • Organobentonite modified with hexadecyltrimethylammonium (HDTMA) was used to quantify an adsorption of heavy metals. Based on preliminary experiments, optimal soil/solution ratio, a range of pH, and electrolyte were selected. Adsorption experiments of cadmium and lead were conducted to quantify an adsorption selectivity to bentonite and organobentonite. Adsorption of cadmium and lead to bentonite was increased with increasing a soil/solution ratio. Adsorption of cadmium and lead to bentonite was increased with increasing a soil/solution ratio. Adsorptions of heavy metal to organobentonite were slightly reduced relative to bentonite. This study used the principle of hard-soft-acid-base (HBAB) to interpretate an adsorption mechanism. Because of competition between cadmium and lead. adsorption of cadmium and lead was reduced in mixture of heavy metals. Adsorption selectivity.

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A Study on the Variation of Physical Properties by the Water to Cement Ratio and the Mixing Speed for Grout Materials (그라우트재의 물시멘트비 및 혼합속도에 의한 물성변화에 관한 연구)

  • 천병식;김진춘;장의웅;송성호;이준우
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.445-452
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    • 2001
  • Generally, OPC(ordinary portland cement) is used for grouting in Korea, and bentonite has usually been added to prevent the deposition of cement particles. The dispersion of CB(cement bentonite) grout is influenced by variable factors i.e. water to cement ratio, particle size of cement, kind of bentonite, adding volume, methods of adding, viscosity of CB grout materials and curdling time. Among variable factors, the viscosity of CB grout materials is influenced by the dispersion, and dispersion is improved as increasing the mixing speed. In this paper, described a suitable mixing speed of the High Speed Mixer in field, engineering characteristics of CB grout materials vary with the water to cement ratio and the mixing speed as well as confirming the state of dispersion.

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Evaluation of the Effects of a Combination of Silicate Minerals in Duck Diets on Growth Performance and Litter Quality

  • Chung, Tae-Ho
    • Journal of Environmental Science International
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    • v.27 no.10
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    • pp.933-936
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    • 2018
  • An experiment was conducted to evaluate the efficacy of a mixture of bentonite and illite as feed additives on the growth performance and litter quality of 90 Pekin ducks. The ducks were individually weighed and randomly divided into two treatments (control and 1% combination of silicate minerals), with three replicate pens per treatment, and 15 ducks per pen. Growth performance was not significantly affected (p>0.05) by the combination of bentonite and illite, but a trend of increased growth performance was observed in the control groups. Total nitrogen content and pH in the litter decreased following supplementation with the combination of bentonite and illite (p<0.05) when compared with the control group. This data indicates that the dietary supplementation with the combination of bentonite and illite (1% level) has no positive effect on the growth performance and litter quality of Pekin ducks.

Thermal Conductivity Enhancement of Bentonite Grout Using Silica Sands (실리카샌드 첨가에 의한 벤토나이트 그라우트의 열전도도 증가)

  • Sohn, Byong-Hu
    • Proceedings of the SAREK Conference
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    • pp.713-718
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    • 2006
  • This paper concerns the measurement of thermal conductivity of grouting materials for ground loop heat exchanger. A thermal conductivity meter, QTM-500 based on modified transient hot wire method was used to measure the thermal conductivity of neat bentonite and mixtures of bentonite and various additives. Relative to the total mixture mass, as the percent additive was increased the mixture thermal conductivity increased. For the bentonite-silica sand mixtures, the higher density of the sand particles resulted in much higher mixture thermal conductivity.

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Hydraulic Properties of Geosynthetic Clay Liners with Bentonite Composition (벤토나이트 혼합조성에 의한 Geosynthetic Clay Liners의 수리학적 특성)

  • Kim, Yoon-Jin;Kim, Min-Sun;Choi, Chang-Nam;Lyoo, Won-Seok;Jeon, Han-Yong
    • Textile Science and Engineering
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    • v.46 no.4
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    • pp.205-211
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    • 2009
  • This study analyzes a hydraulic performance of GCL (geosynthetic clay liners) with and without swelling accelerating material, SAP(Super Absorbent Polymer). In the evaluation of hydraulic performance of GCL, free swell index and triaxial compression permeability tester were used by falling head permeability tester in the evaluation of hydraulic performance with the mixed soil of decomposed granite and bentonite. Permittivity of weathered granite soil and bentonite mixture was increased with SAP content and permeability of this mixture soil was also increased till bentonite content 10%.

Swelling Behavior Evaluation of Bentonite with Additives Mixture (첨가제 혼합에 의한 벤토나이트의 팽윤거동 평가)

  • Kim, Cho-Rong;Kim, Joo-Hee;Lyoo, Won-Seok;Joo, Chang-Whan;Jeon, Han-Yong
    • Textile Science and Engineering
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    • v.46 no.6
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    • pp.326-333
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    • 2009
  • Variation of free swell index of powder and granular bentonite in distilled water were reviewed. For this, four types of additives is used such as starch (SC), sodium carboxy-methyl cellulose (SCMC), polyvinyl alcohol (PVA-Iand PVA-II), super absorbent polymer (SAP). For PVA-I and PVA-II, free swell index increased with 0.2 g addition. However, SC showed a little increase and SCMC showed higher increase. Especially for SAP addition, powder bentonite has larger free swell index to compare with granular bentonite. The sequence of contribution to free swell index of bentonite in descending order is SAP, SCMC, PVA-II, PVA-I, and SC.

Experimental Study on Thermal Conductivity and Viscosity of Grouts for Backfilling Ground Heat Exchanger (수직 밀폐형 자중 열교환기용 뒤채움재의 열전도 및 점도특성 연구)

  • Choi, Hang-Seok;Lee, Chul-Ho;Gil, Hu-Jeong;Choi, Hyo-Pum;Woo, Sang-Baik
    • New & Renewable Energy
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    • v.3 no.4
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    • pp.38-46
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    • 2007
  • In order to characterize the thermal conductivity and viscosity of grout materials used for backfilling ground heat exchangers, nine bentonite grouts and cement grouts being adapted in the United State have been considered in this study. The bentonite grouts indicate that the thermal conductivity and viscosity increase with the content of bentonite or filler (silica sand). In addition, material segregation can be observed when the viscosity of grout is relatively low. The saturated cement grouts appear to possess much higher thermal conductivity than the saturated bentonite grouts, and the reduction of thermal conductivity in the cement grouts after drying specimens is less than the case of the bentonite grouts. Maintaining the moisture content of grouts is a crucial factor in enhancing the efficiency of ground heat exchangers.

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Experimental Study on Thermal Conductivity and Viscosity of Grouts for Backfilling Ground Heat Exchanger (수직 밀페형 지증 열교환기용 뒤채움재의 열전도 및 점도특성 연구)

  • Choi, Hang-Seok;Lee, Chul-Ho;Gil, Hu-Jeong;Choi, Hyo-Pum;Woo, Sang-Baik
    • 한국신재생에너지학회:학술대회논문집
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    • pp.529-532
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    • 2007
  • In order to characterize the thermal conductivity and viscosity of grout materials used for backfilling ground heat exchangers, nine bentonite grouts and cement grouts being adapted in the United State have been considered in this study. The bentonite grouts indicate that the thermal conductivity and viscosity increase with the content of bentonite or filler (silica sand). In addition, material segregation can be observed when the viscosity of grout is relatively low. The saturated cement grouts appear to possess much higher thermal conductivity than the saturated bentonite grouts, and the reduction of thermal conductivity in the cement grouts after drying specimens is less than in case of the bentonite grouts. Maintaining the moisture content of grouts is a crucial factor in enhancing the efficiency of ground heat exchangers.

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A study on cement-based grout for ground heat exchangers (지중 열교환기용 시멘트 그라우트에 관한 연구)

  • Lee, Dong-Ju;Baek, Hwan-Jo;Kim, Gyoung-Man
    • Journal of Industrial Technology
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    • v.31 no.B
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    • pp.27-36
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    • 2011
  • In this paper, the applicability of cement grout has been studied as an alternative to bentonite grout for backfill ground heat exchangers. To provide an optimal mixture design, the thermal conductivity of cement grout and bentonite grout with various mixture ratios were experimentally evaluated and compared. Numerical analyses using Fluent(FVM program) were applied to compare the thermal transfer efficiency of the cement grout with that of the bentonite grout used in the construction. Also the effective ground thermal conductivity was measured by In-situ thermal response test. The results showed that the thermal efficiency of the cement grout was better than the bentonite grout. Consequently, the cement grout could be an alternative with more thermal efficiency to bentonite grout for ground heat exchangers.

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Thermal Conductive Characteristics and Basic Properties of Bentonite Grouts for the Ground Heat Exchanger of Geo-source Heat Pump (지열히트펌프 지중열교환기용 벤토나이트계 그라우트재의 열전도특성 및 기본성능)

  • Bai, Kang
    • Journal of the Korean Solar Energy Society
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    • v.33 no.1
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    • pp.66-72
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    • 2013
  • In this study, the thermal conductive characteristics and basic properties of the nine commercial products of bentonite grouts were studied. Six of the nine products for ground heat exchanger systems are imported and others for civil engineering are domestic. The thermal conductivities of all bentonite products are nearly similar among products. The free swell indexes, viscosities and filter losses of the ground heat exchanger grouts are lower than those of the civil engineering ones. These characteristics seem to increase of the fluidity to fill the bentonite slurry to bore-hall perfectly, rather than to prevent underground water penetration. Thus, the mixtures of bentonites and sands are recommended for high thermal conduction grouts.