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Sample records for selenate-se treated clay

  1. Reagent for treating clay drilling muds

    Energy Technology Data Exchange (ETDEWEB)

    Tkachenko, P V; Leshchinskiy, P A; Shnaper, B I; Zinchuk, I F; Zlobin, V P

    1982-01-01

    A reagent is proposed for treating clay drilling muds. It contains lignite, caustic soda and modifying agent. It is distinguished by the fact that in order to reduce the cost of the reagent with simultaneous decrease in the viscosity and static shear stress of the drilling mud, it additionally contains iron sulfate, and the modifying agent contained is wastes of carbonic acid production with the following ratio of components (parts by weight): lignite 10.0-15.0, caustic soda 2.0-3.0, wastes of carbonic acid production 0.5-0.75; iron sulfate 1.0-2.0.

  2. Analysis of cement-treated clay behavior by micromechanical approach

    OpenAIRE

    Zhang , Dong-Mei; Yin , Zhenyu; Hicher , Pierre Yves; Huang , Hong-Wei

    2013-01-01

    International audience; Experimental results show the significant influence of cement content on the mechanical properties of cement-treated clays. Cementation is produced by mixing a certain amount of cement with the saturated clay. The purpose of this paper is to model the cementation effect on the mechanical behavior of cement-treated clay. A micromechanical stress-strain model is developed considering explicitly the cementation at inter-cluster contacts. The inter-cluster bonding and debo...

  3. Comparing the influence of selenite (Se4+) and selenate (Se6+) on the inhibition of the mercury (Hg) phytotoxicity to pak choi.

    Science.gov (United States)

    Tran, Thi Anh Thu; Dinh, Quang Toan; Cui, Zeiwei; Huang, Jie; Wang, Dan; Wei, Tianjiao; Liang, Dongli; Sun, Xin; Ning, Ping

    2018-01-01

    Selenite (Se (IV)) and selenate (Se (IV)) have recently been demonstrated to be equally effective in inhibiting mercury (Hg) phytotoxicity to plants. This assertion is still unclear. In this study, we aimed to explore the potential effects of Se species (Se 4+ and Se 6+ ) on the inhibition of the mercury (Hg) bioavailability to pak choi in dry land. Pot experiments with exposure to different dosages of mercuric chloride (HgCl 2 ) and selenite (Na 2 SeO 3 ) or selenate (Na 2 SeO 4 ) were treated. To compare the influence of Se (IV) and Se (VI) on the bioaccumulation and bioavailability of Hg, the levels of total Hg in different pak choi (Brassica chinensis L.) tissues (roots and shoots) and the distribution changes of Hg fractions in soil before planting and after harvest were determined as well as the Hg I R values in soils (relative binding intensity) were analyzed. Results showed that application Se (IV) reduced the concentrations of Hg in pak choi roots more than Se (VI). Hg concentrations were also decreased in pak choi shoots in Se (IV) treatments, while which notably increased in Se (VI) treatments. Thus, Se (IV) plays a more important role than Se (VI) in limiting the absorption and bioaccumulation of Hg in pak choi. Moreover, this inhibition may only significantly occur when Se (IV) is at an appropriate level (2.5mg/kg). In addition, the good correlations between the proportions of mobile Hg fractions (soluble and exchangeable fractions), I R values with the Hg concentrations in plants were observed. This affirmed the importance of the Hg fractions transformation and the I R indicator of Hg in the assessment of their bioavailability. Our findings regarding the importance of Se (IV) influence in reducing Hg bioaccumulation not only provided the correct appraisal about the effect of Se species on the inhibition of the Hg phytotoxicity to pak choi in dry land, but also be a good reference for selecting Se fertilizer forms (Se 4+ or Se 6+ ). Copyright © 2017

  4. Preparation and Characterization of Acid and Alkaline Treated Kaolin Clay

    Directory of Open Access Journals (Sweden)

    Sachin Kumar

    2013-06-01

    Full Text Available Kaolin was refluxed with HNO3, HCl, H3PO4, CH3COOH, and NaOH of 3M concentration at 110 °C for 4 hours followed by calcination at 550 °C for 2 hours. The physico-chemical characteristics of resulted leached kaolinite clay were studied by XRF, XRD, FTIR, TGA, DTA, SEM and N2 adsorption techniques. XRF and FTIR study indicate that acid treatment under reflux conditions lead to the removal of the octahedral Al3+ cations along with other impurities. XRD of acid treated clay shows that, the peak intensity was found to decrease. Extent of leaching of Al3+ ions is different for different acid/base treatment. The acid treatment increased the Si/Al ratio, surface area and pore volume of the clay. Thus, the treated kaolin clay can be used as promising adsorbent and catalyst supports. © 2013 BCREC UNDIP. All rights reservedReceived: 1st March 2013; Revised: 9th April 2013; Accepted: 19th April 2013[How to Cite: Kumar, S., Panda, A. K., Singh, R.K. (2013. Preparation and Characterization of Acids and Alkali Treated Kaolin Clay. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 61-69. (doi:10.9767/bcrec.8.1.4530.61-69][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4530.61-69] |View in  |

  5. High-Strengthening of Cement-Treated Clay by Mechanical Dehydration

    OpenAIRE

    Kasama, Kiyonobu; Zen, Kouki; Iwataki, Kiyoharu; 笠間, 清伸; 善, 功企; 岩瀧, 清治

    2007-01-01

    A technique called the cement-mixing and mechanical dehydration method (CMD) as one of recycling techniques for soft clay slurry is developed. In order to evaluate the effectiveness of the CMD for increasing the strength of soft clay, a series of unconfined compression tests and several durability tests were performed together with the literature review of unconfined compressive strength in cement-treated soils. Moreover, a series of constant strain rate consolidation tests were also performe...

  6. Soil-Water Characteristic Curves of Red Clay treated by Ionic Soil Stabilizer

    Science.gov (United States)

    Cui, D.; Xiang, W.

    2009-12-01

    The relationship of red clay particle with water is an important factor to produce geological disaster and environmental damage. In order to reduce the role of adsorbed water of red clay in WuHan, Ionic Soil Stabilizer (ISS) was used to treat the red clay. Soil Moisture Equipment made in U.S.A was used to measure soil-water characteristic curve of red clay both in natural and stabilized conditions in the suction range of 0-500kPa. The SWCC results were used to interpret the red clay behavior due to stabilizer treatment. In addition, relationship were compared between the basic soil and stabilizer properties such as water content, dry density, liquid limit, plastic limit, moisture absorption rate and stabilizer dosages. The analysis showed that the particle density and specific surface area increase, the dehydration rate slows and the thickness of water film thins after treatment with Ionic Soil Stabilizer. After treatment with the ISS, the geological disasters caused by the adsorbed water of red clay can be effectively inhibited.

  7. Speciation of uranium in surface-modified, hydrothermally treated, (UO2)2+-exchanged smectite clays

    International Nuclear Information System (INIS)

    Giaquinta, D.M.; Soderholm, L.; Yuchs, S.E.; Wasserman, S.R.

    1997-01-01

    A successful solution to the problem of disposal and permanent storage of water soluble radioactive species must address two issues: exclusion of the radionuclides from the environment and the prevention of leaching from the storage media into the environment. Immobilization of radionuclides in clay minerals has been studied. In addition to the use of clays as potential waste forms, information about the interactions of radionuclides with clays and how such interactions affect their speciations is crucial for successful modeling of actinide-migration. X-ray absorption spectroscopy (XAS) is used to determine the uranium speciation in exchanged and surface-modified clays. The XAS data from uranyl-loaded bentonite clay are compared with those obtained after the particle surfaces have been coated with alkylsilanes. These silane films, which render the surface of the clay hydrophobic, are added in order to minimize the ability of external water to exchange with the water in the clay interlayer, thereby decreasing the release rate of the exchanged-uranium species. Mild hydrothermal conditions are used in an effort to mimic potential geologic conditions that may occur during long-term radioactive waste storage. The XAS spectra indicate that the uranyl monomer species remain unchanged in most samples, except in those samples that were both coated with an alkylsilane and hydrothermally treated. When the clay was coated with an organic film, formed by the acidic deposition of octadecyltrimethoxysilane, hydrothermal treatment results in the formation of aggregated uranium species in which the uranium is reduced from U VI to U IV

  8. Investigation of mineral composition of differently treated devonian, quaternary and triassic clays of Latvia

    International Nuclear Information System (INIS)

    Kosorukovs, A.; Viss, R.

    1999-01-01

    Clayey fractions (particle size less than 5 μm )of the Latvian Devonian (Kuprava and Liepa deposits), Quaternary (Laza and Ugale deposits) and Triassic (Akmene deposit, Republic of Lithuania) clays have been obtained. The clayey fractions were converted in the form in which all the cations were exchanged for magnesium ions. After the ion exchange the fractions were treated with dimethyl sulfoxide or glycerol in the course for two days, one sample being subjected to thermal treatment at 550±110 C for two hours. Diffractograms for the treated samples have been obtained using a DRON-2,0 diffractometer (Co-radiation). Analysis of the obtained diffractograms show that: 1) the main clayey minerals of the Devonian clays occur to be hydromicas (mainly hydromuscovite) containing admixtures of kaolinite and quartz; 2) the main clayey minerals of the Quarternary clays also occur to be hydromicas - mixtures of hydrobiotite and hydromuscovite containing admixtures of kaolinite and iron-containing chlorite; 3) smectite occurs to be the main mineral of the Triassic clay; it contains admixtures of hydromica and chlorite; 4) the Triassic and Quaternary clays contain fine- and coarse-grained carbonates, mainly calcite, in quantities of 10-16%; 5) iron and titanium are included in fine grained minerals. (author)

  9. Shear strength and compressibility behaviour of lime-treated organic clay

    OpenAIRE

    Yunus, NZM; Wanatowski, D; Hassan, NA; Marto, A

    2016-01-01

    Apart from strength characteristics, a review of studies on the compressibility of lime-treated soils is equally important that influenced the stability of soil structures. Due to the fact that no study has been carried out, an investigation on the effects of humic acid on strength and compressibility behaviour of lime-stabilised organic clay is presented in this paper. Unconfined Compressive Strength (UCS) and oedometer tests were carried out at different curing periods of 7, 28 and 90 days....

  10. Preparation and characterization of electron-beam treated HDPE composites reinforced with rice husk ash and Brazilian clay

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, A.V., E-mail: angelortiz@ipen.br [Nuclear and Energy Research Institute, IPEN-CNEN/SP Av. Prof. Lineu Prestes 2242, São Paulo, SP 05508-000 (Brazil); Teixeira, J.G.; Gomes, M.G.; Oliveira, R.R. [Nuclear and Energy Research Institute, IPEN-CNEN/SP Av. Prof. Lineu Prestes 2242, São Paulo, SP 05508-000 (Brazil); Díaz, F.R.V. [Metallurgical and Materials Engineering Department, Polytechnic School, University of São Paulo Av. Prof. Mello de Morais 2463, São Paulo, SP 05508-900 (Brazil); Moura, E.A.B. [Nuclear and Energy Research Institute, IPEN-CNEN/SP Av. Prof. Lineu Prestes 2242, São Paulo, SP 05508-000 (Brazil)

    2014-08-15

    Highlights: • We examine changes in HDPE properties when waste and clay are used as reinforcement. • The addition of only 3% of clay leads to important gains in HDPE properties. • The use of electron-beam contributes to greater improvements in material properties. • We observe 85% of cross-linking degree for the HDPE when treated with e-beam. - Abstract: This work evaluates the morphology, mechanical and thermo-mechanical properties of high density polyethylene (HDPE) composites. HDPE reinforced with rice husk ashes (80:20 wt%), HDPE reinforced with clay (97:3 wt%) and HDPE reinforced with both rice husk ashes and clay(77:20:3 wt%) were obtained. The Brazilian bentonite chocolate clay was used in this study. This Brazilian smectitic clay is commonly used to produce nanocomposites. The composites were produced by melting extrusion process and then irradiation was carried out in a 1.5 MeV electron-beam accelerator (room temperature, presence of air). Comparisons using the irradiated and non-irradiated neat polymer, and the irradiated and non-irradiated composites were made. The materials obtained were submitted to tensile, flexural and impact tests. Additionally HDT, SEM and XRD analyses were carried out along with the sol–gel analysis which aimed to assess the cross-linking degree of the irradiated materials. Results showed great improvement in most HDPE properties and a high cross-linking degree of 85% as a result of electron-beam irradiation of the material.

  11. Performance of soft clay stabilized with sand columns treated by silica fume

    Directory of Open Access Journals (Sweden)

    Samueel Zeena

    2018-01-01

    Full Text Available In many road construction projects, if weak soil exists, then uncontrollable settlement and critical load carrying capacity are major difficult problems to the safety and serviceability of roads in these areas. Thus ground improvement is essential to achieve the required level of performance. The paper presents results of the tests of four categories. First category was performed on saturated soft bed of clay without any treatment, the second category shed light on the improvement achieved in loading carrying capacity and settlement as a result of reinforcing with conventional sand columns at area replacement ratio = 0.196. The third set investigates the bed reinforced by sand columns stabilized with dry silica fume at different percentages (3, 5 and 7% and the fourth set investigates the behavior of sand columns treated with slurry silica fume at two percentages (10 and 12%. All sand columns models were constructed at (R.D= 60%. Model tests were performed on bed of saturated soil prepared at undrained shear strength between 16-20 kPa for all models. For all cases, the model test was loaded gradually by stress increments up to failure. Stress deformation measurements are recorded and analyzed in terms of bearing improvement ratio and settlement reduction ratio. Optimum results were indicated from soil treated with sand columns stabilized with 7% dry silica fume at medium state reflecting the highest bearing improvement ratio (3.04 and the settlement reduction ratio (0.09 after 7 days curing. While soil treated with sand columns stabilized with 10% slurry silica fume provided higher bearing improvement ratio 3.13 with lower settlement reduction ratio of 0.57 after 7-days curing.

  12. Compaction and Plasticity Comparative Behaviour of Soft Clay Treated with Coarse and Fine Sizes of Ceramic Tiles

    Science.gov (United States)

    Al-Bared, Mohammed Ali Mohammed; Marto, Aminaton; Sati Hamonangan Harahap, Indra; Kasim, Fauziah

    2018-03-01

    Recycled blended ceramic tiles (RBT) is a waste material produced from ceramic tile factories and construction activities. RBT is found to be cost effective, sustainable, environmental-friendly and has the potential to be used as an additive in soft soil stabilization. Recent reports show that massive amounts of RBT are dumped into legal or illegal landfills every year consuming very large spaces and creating major environmental problems. On the other hand, dredged marine clay obtained from Nusajaya, Johor, Malaysia has weak physical and engineering characteristics to be considered as unsuitable soft soil that is usually excavated, dumped into landfills and replaced by stiff soil. Hence, this study investigates the suitability of possible uses of RBT to treat marine clay. Laboratory tests included Standard proctor tests and Atterberg limits tests. The plasticity of marine clay was evaluated by adding 10%, 20%, 30% and 40% of 0.3 mm RBT. In addition, the compaction behaviour of treated marine clay was compared by adding two different sizes (0.3 mm and 1.18 mm diameter) of RBT. For both coarse and fine sizes of RBT, 10%, 20%, 30% and 40% of the dry weight of the soft clay were added. The mixture of each combination was examined in order to evaluate the Maximum Dry Density (MDD) and the optimum moisture content (OMC) for the treated soft clay. MDD and OMC for soft untreated samples were 1.59 Mg/m3 and 22%, respectively. Treated samples with 10%, 20%, 30% and 40% of 0.30 mm size RBT resulted in a significant reduction of OMC ranged from 19 to 15% while MDD resulted in increment ranged from 1.69 to 1.77 Mg/m3. In addition, samples treated with 10%, 20%, 30% and 40% of 1.18 mm size RBT resulted in major reduction of OMC ranged from 15 to 13.5% while MDD increased effectively from 1.75 to 1.82 Mg/m3. For all mix designs of soft clay-RBT, MDD was gradually increasing and OMC was sharply reducing with further increments of both sizes of RBT.

  13. Compaction and Plasticity Comparative Behaviour of Soft Clay Treated with Coarse and Fine Sizes of Ceramic Tiles

    Directory of Open Access Journals (Sweden)

    Al-Bared Mohammed Ali Mohammed

    2018-01-01

    Full Text Available Recycled blended ceramic tiles (RBT is a waste material produced from ceramic tile factories and construction activities. RBT is found to be cost effective, sustainable, environmental-friendly and has the potential to be used as an additive in soft soil stabilization. Recent reports show that massive amounts of RBT are dumped into legal or illegal landfills every year consuming very large spaces and creating major environmental problems. On the other hand, dredged marine clay obtained from Nusajaya, Johor, Malaysia has weak physical and engineering characteristics to be considered as unsuitable soft soil that is usually excavated, dumped into landfills and replaced by stiff soil. Hence, this study investigates the suitability of possible uses of RBT to treat marine clay. Laboratory tests included Standard proctor tests and Atterberg limits tests. The plasticity of marine clay was evaluated by adding 10%, 20%, 30% and 40% of 0.3 mm RBT. In addition, the compaction behaviour of treated marine clay was compared by adding two different sizes (0.3 mm and 1.18 mm diameter of RBT. For both coarse and fine sizes of RBT, 10%, 20%, 30% and 40% of the dry weight of the soft clay were added. The mixture of each combination was examined in order to evaluate the Maximum Dry Density (MDD and the optimum moisture content (OMC for the treated soft clay. MDD and OMC for soft untreated samples were 1.59 Mg/m3 and 22%, respectively. Treated samples with 10%, 20%, 30% and 40% of 0.30 mm size RBT resulted in a significant reduction of OMC ranged from 19 to 15% while MDD resulted in increment ranged from 1.69 to 1.77 Mg/m3. In addition, samples treated with 10%, 20%, 30% and 40% of 1.18 mm size RBT resulted in major reduction of OMC ranged from 15 to 13.5% while MDD increased effectively from 1.75 to 1.82 Mg/m3. For all mix designs of soft clay-RBT, MDD was gradually increasing and OMC was sharply reducing with further increments of both sizes of RBT.

  14. Characterization of Heat-treated Clay Minerals in the Context of Nuclear Waste Disposal

    Science.gov (United States)

    Matteo, E. N.; Wang, Y.; Kruichak, J. N.; Mills, M. M.

    2015-12-01

    Clay minerals are likely candidates to aid in nuclear waste isolation due to their low permeability, favorable swelling properties, and high cation sorption capacities. Establishing the thermal limit for clay minerals in a nuclear waste repository is a potentially important component of repository design, as flexibility of the heat load within the repository can have a major impact on the selection of repository design. For example, the thermal limit plays a critical role in the time that waste packages would need to cool before being transferred to the repository. Understanding the chemical and physical changes, if any, that occur in clay minerals at various temperatures above the current thermal limit (of 100 °C) can enable decision-makers with information critical to evaluating the potential trade-offs of increasing the thermal limit within the repository. Most critical is gaining understanding of how varying thermal conditions in the repository will impact radionuclide sorption and transport in clay materials either as engineered barriers or as disposal media. A variety of repository-relevant clay minerals (illite, mixed layer illite/smectite, and montmorillonite), were heated for a range of temperatures between 100-1000 °C. These samples were characterized to determine surface area, mineralogical alteration, and cation exchange capacity (CEC). Our results show that for conditions up to 500 °C, no significant change occurs, so long as the clay mineral remains mineralogically intact. At temperatures above 500 °C, transformation of the layered silicates into silica phases leads to alteration that impacts important clay characteristics. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's Nation Nuclear Security Administration under contract DE-AC04-94AL85000. SAND Number: SAND2015-6524 A

  15. Treatment of Liquid Oil Spill by Untreated and Treated Aswanly Clay ...

    African Journals Online (AJOL)

    The aim of this work is to use cheap, available and recyclable sorbents for oil spill clean – up. α -SiO2-Quartz, Na2Si2O5(OH)4, CaCO3, MgCO3, BaCO3, CaO, MgO, ... Characteristics of crude oil and Aswanly clay were investigated by FTIR, X – Ray Fluorescence, X – Ray Diffraction, pour point and centrifuge instruments.

  16. Study and development of nanocomposites PBT/bentonite clay treated by ionizing radiation: preparation and characterization

    International Nuclear Information System (INIS)

    Sartori, Mariana do Nascimento

    2014-01-01

    This work describes the preparation and characterization of composites based on poly (butylene terephthalate) - PBT and brazilian modified clay prepared by the melt intercalation. PBT nanocomposites with 3 and 5 % by weight of organically modified clay, by the addition of a quaternary ammonium salt, were prepared by extrusion using a twin-screw extruder machine. After the extrusion process, the materials were injected to obtain specimens tests samples for the characterization tests. Part of the specimens samples were irradiated using an electron beam accelerator with 1.5 MeV at room temperature in the presence of air. Samples of pure PBT and irradiated and non-irradiated nanocomposites were characterized by mechanical tests of tensile, flexural and impact, heat distortion temperature (HDT), X - ray diffraction (XRD), scanning electron microscopy (SEM), melt flow index (MFI) thermogravimetry (TG) and differential scanning calorimetry (DSC) and the correlation between the properties was discussed. The results showed that the addition of clay, in both percentages, promoted an increase greater than 50 % in tensile strength at break and a gain of around 35% in heat distortion temperature when compared to the pure polymer. The treatment with ionizing radiation of electron beam at the doses used in this study showed no significant changes in material properties. (author)

  17. Approaches for treating uncertainty in the long term performance assessment of a geological waste repository in clay

    International Nuclear Information System (INIS)

    Marivoet, J.; Volckaert, G.; Wemaere, I.; Mallants, D.

    1998-01-01

    In Belgium the current strategy for high-level waste disposal is the geological disposal in a plastic clay layer. The performance assessment approach consists of a systematic scenario selection based on the FEP (features, events and processes) methodology followed by consequence analyses for the selected scenarios. In these consequence analyses the different sources of uncertainty are systematically considered. For the normal evolution scenario, i.e. the scenario which includes all FEP's which are about certain to occur, a stochastic technique of the Monte Carlo type is applied for treating uncertainty. For the altered evolution scenarios a deterministic approach is generally used to evaluate the uncertainties on the long-term. In the case of altered evolution scenarios, comparisons of fluxes from the far field into the biosphere with those calculated for the normal evolution scenario are used, beside dose calculations, to evaluate the safety consequences. Some typical examples of the above approaches will be presented. (author)

  18. Mild acid and alkali treated clay minerals enhance bioremediation of polycyclic aromatic hydrocarbons in long-term contaminated soil: A 14C-tracer study.

    Science.gov (United States)

    Biswas, Bhabananda; Sarkar, Binoy; Rusmin, Ruhaida; Naidu, Ravi

    2017-04-01

    Bioremediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soils requires a higher microbial viability and an increased PAH bioavailability. The clay/modified clay-modulated bacterial degradation could deliver a more efficient removal of PAHs in soils depending on the bioavailability of the compounds. In this study, we modified clay minerals (smectite and palygorskite) with mild acid (HCl) and alkali (NaOH) treatments (0.5-3 M), which increased the surface area and pore volume of the products, and removed the impurities without collapsing the crystalline structure of clay minerals. In soil incubation studies, supplements with the clay products increased bacterial growth in the order: 0.5 M HCl ≥ unmodified ≥ 0.5 M NaOH ≥ 3 M NaOH ≥ 3 M HCl for smectite, and 0.5 M HCl ≥ 3 M NaOH ≥ 0.5 M NaOH ≥ 3 M HCl ≥ unmodified for palygorskite. A 14 C-tracing study showed that the mild acid/alkali-treated clay products increased the PAH biodegradation (5-8%) in the order of 0.5 M HCl ≥ unmodified > 3 M NaOH ≥ 0.5 M NaOH for smectite, and 0.5 M HCl > 0.5 M NaOH ≥ unmodified ≥ 3 M NaOH for palygorskite. The biodegradation was correlated (r = 0.81) with the bioavailable fraction of PAHs and microbial growth as affected particularly by the 0.5 M HCl and 0.5 M NaOH-treated clay minerals. These results could be pivotal in developing a clay-modulated bioremediation technology for cleaning up PAH-contaminated soils and sediments in the field. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Argon plasma treated electrospun P(Hola-E-Cl) Clay nanofiber composite: Effect on its antibacterial activity against S. Aureus and E.Coli

    International Nuclear Information System (INIS)

    Monserate, Juvy J.; Sumera, Florentino C.; Ramos, Henry J.; Daseco, Joanna Abigael

    2015-01-01

    In this work, the effects of argon plasma surface modification have been studied on electrospun P(HOLA-e-CL) Clay Nanofiber Composites in order to investigate the imposed limitation and possibilities to improve surface characteristics on fibrous assemblies. These assemblies were characterized using Scanning Electron Microscopy to determine the surface morphology and diameter size of the fiber. Fourier Transform Infrared Spectroscopy (FTIR) was employed to find out the positions of peaks similar to the constituent components incorporated during the process of polymerization which implied that the IR spectra illustrated the evidence of an interaction between clay and the polymer matrix. XRD peaks on increasing d-spacing going to the left 2?<20 0 verifies the results of interaction between the polymer and the ALA-MMT nanoclay. Thus this also suggested that the polymer was intercalated into the ALA-MMT. The Argon Plasma electrospun nanofiber was subjected to its antibacterial property against S. aureaus (gram positive) and E. coli (gram negative) bacteria. DMRT statistically revealed significantly at 5% level of significance shows that all treatments at increasing clay loading inhibit the growth of S. Aureus and E. Coli. Thus, Argon Plasma treated electrospun P(HOLA-e-CL) Clay Nanofiber Composites can be an excellent scaffold material for wound dressing applications. (author)

  20. Clay Play

    Science.gov (United States)

    Rogers, Liz; Steffan, Dana

    2009-01-01

    This article describes how to use clay as a potential material for young children to explore. As teachers, the authors find that their dialogue about the potential of clay as a learning medium raises many questions: (1) What makes clay so enticing? (2) Why are teachers noticing different play and conversation around the clay table as compared to…

  1. Ball clay

    Science.gov (United States)

    Virta, R.L.

    2001-01-01

    Part of the 2000 annual review of the industrial minerals sector. A general overview of the ball clay industry is provided. In 2000, sales of ball clay reached record levels, with sanitary ware and tile applications accounting for the largest sales. Ball clay production, consumption, prices, foreign trade, and industry news are summarized. The outlook for the ball clay industry is also outlined.

  2. SBR Brazilian organophilic/clay nanocomposites

    International Nuclear Information System (INIS)

    Guimaraes, Thiago R.; Valenzuela-Diaz, Francisco R.; Morales, Ana Rita; Paiva, Lucilene B.

    2009-01-01

    The aim of this work is the obtaining of SBR composites using a Brazilian raw bentonite and the same bentonite treated with an organic salt. The clays were characterized by XRD. The clay addition in the composites was 10 pcr. The composites were characterized by XRD and had measured theirs tension strength (TS). The composite with Brazilian treated clay showed TS 233% higher than a composite with no clay, 133% higher than a composite with Cloisite 30B organophilic clay and 17% lower than a composite with Cloisite 20 A organophilic clay. XRD and TS data evidence that the composite with Brazilian treated clay is an intercalated nanocomposite. (author)

  3. Clay Houses

    Science.gov (United States)

    Pedro, Cathy

    2011-01-01

    In this article, the author describes a project designed for fourth-graders that involves making clay relief sculptures of houses. Knowing the clay houses will become a family heirloom makes this lesson even more worth the time. It takes three classes to plan and form the clay, and another two to underglaze and glaze the final products.

  4. Root-Zone Redox Dynamics - In Search for the Cause of Damage to Treated-Wastewater Irrigated Orchards in Clay Soils

    Science.gov (United States)

    Yalin, David; Shenker, Moshe; Schwartz, Amnon; Assouline, Shmuel; Tarchitzky, Jorge

    2016-04-01

    Treated wastewater (TW) has become a common source of water for agriculture. However recent findings raise concern regarding its use: a marked decrease (up to 40%) in yield appeared in orchards irrigated with TW compared with fresh water (FW) irrigated orchards. These detrimental effects appeared predominantly in orchards cultivated in clay soils. The association of the damage with clay soils rather than sandy soils led us to hypothesize that the damage is linked to soil aeration problems. We suspected that in clay soils, high sodium adsorption ratio (SAR) and high levels of organic material, both typical of TW, may jointly lead to an extreme decrease in soil oxygen levels, so as to shift soil reduction-oxidation (redox) state down to levels that are known to damage plants. Two-year continuous measurement of redox potential, pH, water tension, and oxygen were conducted in the root-zone (20-35 cm depth) of avocado trees planted in clay soil and irrigated with either TW or FW. Soil solution composition was sampled periodically in-situ and mineral composition was sampled in tree leaves and woody organs biannually. In dry periods the pe+pH values indicated oxic conditions (pe+pH>14), and the fluctuations in redox values were small in both TW and FW plots. Decreases in soil water tension following irrigation or rain were followed by drops in soil oxygen and pe+pH values. TW irrigated plots had significantly lower minimum pe+pH values compared with FW-irrigated plots, the most significant differences occurred during the irrigation season rather than the rain season. A linear correlation appeared between irrigation volume and reduction severity in TW-irrigated plots, but not in the FW plots, indicating a direct link to the irrigation regime in TW-irrigated plots. The minimum pe+pH values measured in the TW plots are indicative of suboxic conditions (9water tension and oxygen concentration levels. The consequences of our findings to plant health will be discussed, and

  5. The Role of Clay Swelling and Mineral Neoformation in the Stabilization of High Plasticity Soils Treated with the Fly Ash- and Metakaolin-Based Geopolymers

    Directory of Open Access Journals (Sweden)

    Mahmoud A. Mahrous

    2018-04-01

    Full Text Available In the southern U.S. states, expansive soils are frequently encountered, presenting an important hazard in geotechnical engineering. This research relies on mineralogical and geochemical clues to explain the swelling behavior of smectite-rich, high-plasticity soils, documented in a series of geomechanical swelling tests that were performed on the soils stabilized with the metakaolin (MKG and fly ash (FAG based geopolymers. These geopolymers were mixed with the soil at several concentration levels. The lowest swelling percentage was shown to correspond to the sample stabilized with 12% FAG and was attributed to the neoformation of calcium silicate hydrates that acted as a cementitious material, preventing the soil from expanding by occupying the pore space, thus binding the clay particles together. Conversely, the 12% MKG-stabilized soil exhibited enormous expansion, which was explained by montmorillonite swelling to the point that it gradually began to lose its structural periodicity. The relatively high abundance of the newly formed feldspathoids in MKG-treated samples is believed to have greatly contributed to the overall soil expansion. Finally, the cation exchange capacity tests showed that the percentage of Na+ and Ca2+, as well as the pH value, exercised strong control on the swelling behavior of smectitic soils.

  6. clay nanocomposites

    Indian Academy of Sciences (India)

    The present work deals with the synthesis of specialty elastomer [fluoroelastomer and poly (styrene--ethylene-co-butylene--styrene (SEBS)]–clay nanocomposites and their structure–property relationship as elucidated from morphology studies by atomic force microscopy, transmission electron microscopy and X-ray ...

  7. Availability of electro-osmotic process for treating contaminated clays with gasoline; Viabiliadade do processo eletro-osmotico para remediacao de solo argiloso contaminado com gasolina

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Veronica E.; Neri, Katya D. [Universidade Estadual da Paraiba (UEPB), Joao Pessoa, PB (Brazil); Vilar, Eudesio O. [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2008-07-01

    The electrochemical mobilization of organic compounds occurs through simultaneously drag with the interstitial fluid (electrosmosis). For this study of electroremediation it was used a rectangular reactor filled with 1700 g of clay mixture (47% fine sand, 48% bentonite and 5% vermiculite) previously contaminated with gasoline. DSA - electrodes were inserted directly into the soil. The results of efficiency of mobilization to several initial soil moisture content (20-50%), time of experiment (48 - 72 h) and intensity of electric field (1-3 V/Cm) were confronted with the changes of pH, resulting from electrosmosis process. It was observed that the mobilization of the contaminant increased by increasing the time and intensity of electric field, in lower initial moisture. The tests results show that the best conditions for processing are 72 hours, 20% humidity and 3V/cm. In those circumstances it was possible to mobilize 46% of the initial concentration of gasoline, percentage found near the anode. The electrolysis provided soil acidification. It was found soil pH values above 11 near the cathode and below 2 neighbour to the anode, a factor that contributed to produce an electrosmosis reverse flow (cathode-anode flow direction). It is concluded that the mobilization by electrochemistry phenomena of gasoline in clay soil is possible, its efficiency, however depends on the proper control of the conditions of the process including pH (author)

  8. Organic Synthesis using Clay Catalysts

    Indian Academy of Sciences (India)

    cept, though not new, has received enormous attention in recent times. The desire to make ... which they are divided into four main groups such as, illite, smectite .... acid or driving out NH3 by heating the NH4 + ion treated clay. It is clear from ...

  9. Water-dispersible clay in soils treated with sewage sludge Argila dispersa em água em solos tratados com lodo de esgoto

    Directory of Open Access Journals (Sweden)

    João Tavares Filho

    2010-10-01

    Full Text Available A by-product of Wastewater Treatment Stations is sewage sludge. By treatment and processing, the sludge is made suitable for rational and environmentally safe use in agriculture. The aim of this study was to assess the influence of different doses of limed sewage sludge (50 % on clay dispersion in soil samples with different textures (clayey and medium. The study was conducted with soil samples collected from native forest, on a Red Latosol (Brazilian classification: Latossolo Vermelho distroférrico loamy soil in Londrina (PR and a Red-Yellow Latosol (BC: Latossolo Vermelho-Amarelo distrófico medium texture soil in Jaguapitã (PR. Pots were filled with 3 kg of air-dried fine earth and kept in greenhouse. The experiment was arranged in a randomized block design with six treatments: T1 control, and treatments with limed sewage sludge (50 % as follows: T2 (3 t ha-1, T3 (6 t ha-1, T4 (12 t ha-1, T5 (24 t ha-1 and T6 (48 t ha-1 and five replications. The incubation time was 180 days. At the end of this period, the pots were opened and two sub-samples per treatment collected to determine pH-H2O, pH KCl (1 mol L-1, organic matter content, water-dispersible clay, ΔpH (pH KCl - pH-H2O and estimated PZC (point of zero charge: PZC = 2 pH KCl - pH-H2O, as well as the mineralogy of the clay fraction, determined by X ray diffraction. The results showed no significant difference in the average values for water-dispersible clay between the control and the other treatments for the two soil samples studied and ΔpH was the variable that correlated best with water-dispersible clay in both soils.As Estações de Tratamento de Esgoto Sanitário (ETES geram um subproduto (lodo de esgoto que, quando tratado e processado, adquire características que permitem sua utilização agrícola de maneira racional e ambientalmente segura. Este trabalho objetivou avaliar a influência de diferentes doses de lodo de esgoto caleado (50 % na dispersão de argilas em amostras de

  10. Treatment for cracked and permeable Houston clay

    International Nuclear Information System (INIS)

    Vipulanandan, C.; Leung, M.

    1991-01-01

    In this study, the treatability of a field clay (obtained from Houston, Texas) and a clay-sand mixture to reduce their hydraulic conductivity was evaluated. Remolded field clay and clay-sand mixture with and without methanol contamination were treated to reduce their hydraulic conductivity by permeating very dilute grout solutions. The concentration of sodium silicate in the grout solution was 8%, while the solid content in the cement grout was 0.3%. The hydraulic conductivity of permeable Houston clay (hydraulic conductivity >10 -5 cm/sec) could be reduced to less than 10 -7 cm/sec (U.S. EPA limit for soil barriers) by permeating with a selected combination of grout solutions

  11. Synthetic mullite fabrication from smectite clays

    International Nuclear Information System (INIS)

    Lima, L.N. de; Kiminami, R.H.G.A.

    1988-01-01

    The technological importance of mullite is mostly due to its refractory properties. Mullite in native form is very rare, and therefore it may be necessary to produced it by synthetic means. Brazil has a large reserve of smectite clays. In this work the process to produce synthetic mullite from these clays by treatment with aluminum sulphate was studied. X-ray analyses has shown the presence of mullite crystals in treated smectite clays of several colours, sinterized at 1100 0 C. By sintering at 1300 0 C, pure mullite was obtained in some colours. (author) [pt

  12. Influence of chemical treatment of clay to obtain polypropylene nanocomposites

    International Nuclear Information System (INIS)

    Rosa, Jeferson L.S.; Marques, Maria F.V.

    2009-01-01

    Commercial clay was chemically treated to prepare a Ziegler-Natta catalyst containing MgCl 2 and clay for the synthesis of polypropylene nanocomposites by in situ polymerization. The performance of this catalyst and materials obtained in propylene polymerization was compared with a reference catalyst (without clay) and with another, whose composition presents the same clay but without prior chemical treatment. Techniques like differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and melt flow index (MFI) measurements were performed. There was a marked reduction in catalytic activity of clay catalysts in comparison with the reference one, and a slight reduction in melting temperature of the polymers produced from first ones. The melt flow index of polymers obtained with treated clay were notably higher than those synthesized with the untreated clay, so the treated clay caused treated the production of PP's with lower molar mass. The clays showed an increase of spacing and irregular stacking of the lamellas, especially if chemically treated. (author)

  13. Common clay and shale

    Science.gov (United States)

    Virta, R.L.

    2000-01-01

    Part of the 1999 Industrial Minerals Review. The clay and shale market in 1999 is reviewed. In the U.S., sales or use of clay and shale increased from 26.4 million st in 1998 to 27.3 million st in 1999, with an estimated 1999 value of production of $143 million. These materials were used to produce structural clay products, lightweight aggregates, cement, and ceramics and refractories. Production statistics for clays and shales and for their uses in 1999 are presented.

  14. Rheological characterization of nanocomposites Nylon 6/bentonite clay

    International Nuclear Information System (INIS)

    Silva, T.R.G.; Fernandes, P.C.; Oliveira, S.V.; Araujo, E.M.; Melo, T.J.A.

    2010-01-01

    Polymer nanocomposites are a class of materials that have been widely used in various applications. Among them, has been emphasizing the preparation of polymer films with barrier properties for applications in polymer membranes. In this work, nanocomposites of nylon 6/bentonite clay were obtained from a Homogenizer, in the ratios of 1, 3 and 5 wt% clay. The Brasgel PA bentonite clay was treated organically with Praepagen HY salt, to make it organophilic. By X-ray diffraction (XRD), it was showed that the efficiency of the incorporation of salt in the clay. The rheological curves showed that for the AST clay the torque did not change when compared with the pure nylon 6, while for the clay ACT, the torque increased gradually with the percentage of clay. (author)

  15. Thermally modified bentonite clay for copper removal

    International Nuclear Information System (INIS)

    Bertagnolli, C.; Kleinübing, S.J.; Silva, M.G.C.

    2011-01-01

    Bentonite clay coming from Pernambuco was thermally modified in order to increase its affinity and capacity in the copper removal in porous bed. The application of this procedure is justified by the low cost of clay, their abundance and affinity for various metal ions. Thermally treatment modifies the clay adsorption properties enables its use in porous bed system, with the increase in surface area and mechanical strength. The material was characterized by x-ray diffraction, thermogravimetric analysis and N_2 physisorption. Then tests were carried out for adsorption of copper in various experimental conditions and evaluated the mass transfer zone, useful and total adsorbed removal amounts and total copper removal percentage. The results showed that the clay treated at higher temperature showed higher copper removal. (author)

  16. Clay Portrait Boxes

    Science.gov (United States)

    Wilbert, Nancy Corrigan

    2009-01-01

    In an attempt to incorporate sculptural elements into her ceramics program, the author decided to try direct plaster casting of the face to make a plaster mold for clay. In this article, the author shares an innovative ceramics lesson that teaches students in making plaster casts and casting the face in clay. This project gives students the…

  17. Columns in Clay

    Science.gov (United States)

    Leenhouts, Robin

    2010-01-01

    This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

  18. Characterization of clay minerals

    International Nuclear Information System (INIS)

    Diaz N, C.; Olguin, M.T.; Solache R, M.; Alarcon H, T.; Aguilar E, A.

    2002-01-01

    The natural clays are the more abundant minerals on the crust. They are used for making diverse industrial products. Due to the adsorption and ion exchange properties of these, a great interest for developing research directed toward the use of natural clays for the waste water treatment has been aroused. As part of such researches it is very important to carry out previously the characterization of the interest materials. In this work the results of the mineral and elemental chemical composition are presented as well as the morphological characteristics of clay minerals from different regions of the Mexican Republic. (Author)

  19. Absorption characteristics of Kupravas deposit clays modified by phosphoric acid

    International Nuclear Information System (INIS)

    Ruplis, A.; Mezinskis, G.; Chaghuri, M.

    1998-01-01

    Literature data suggested that clays may be used as sorbents for waste water treatment. The surface and sorption properties of minerals changes due to the influence of acid rains. The process of recession of clay properties has been modeled in laboratory by treatment of clays with mineral acids at higher temperature that in natural conditions. The present paper is devoted to the study of influence of phosphoric acid on the sorption properties of Kupravas deposit clays. Natural clay samples and samples treated with phosphoric acid were characterized by means of x-ray diffraction an differential thermal analysis (DTA) methods These methods were used also to identify the sample of Lebanese clays. X-ray diffraction analysis data show that the samples of clays from the deposit of Kuprava contain illite and kaolinite while sample of Lebanese clay contains quartz, calcite, and montmorillonite. DTA results show characteristic features of Kuprava clays described in reference with DTA of Lebanese clay clearly demonstrate the presence of large quantity of calcite

  20. Thixotropic Properties of Latvian Clays

    OpenAIRE

    Lakevičs, Vitālijs; Stepanova, Valentīna; Ruplis, Augusts

    2015-01-01

    This research studies Latvia originated Devon (Tūja, Skaņkalne), quaternary (Ceplīši), Jurassic, (Strēļi) and Triassic (Vadakste) deposit clays as well as Lithuania originated Triassic (Akmene) deposit clays. Thixotropic properties of clay were researched by measuring relative viscosity of clay in water suspensions. Relative viscosity is measured with a hopper method. It was detected that, when concentration of suspension is increased, clay suspension’s viscosity also increases. It happens un...

  1. Effects of clay mineral type and organic matter on the uptake of radiocesium by pasture plants

    International Nuclear Information System (INIS)

    D'Souza, T.J.

    1980-10-01

    Studies were undertaken to examine the influence of interaction of clay minerals and organic matter on the uptake of radiocesium by two pasture plants, namely, ryegrass (Lolium italicum L) and red clover (Trifolium pratense L). The clay minerals used were bentonite (2.1 layer type) and kaolinite (1/1 layer type). Mixtures of clay and sand were prepared with 0.5, 10, 20 and 40 per cent clay and treated with organic matter (forest turf) at 0,5 and 10 per cent of the clay-sand mixtures. Results indicated that 134 Cs uptake by plants grown on the kaolinite-clay medium was greater than that on the bentonite-clay medium at a given organic matter level. Increasing the clay content of mixtures resulted in reduction in 134 Cs uptake by both plant species. The plant uptake of 134 Cs increased with additions of organic matter at a given clay content. (author)

  2. Se of polymers to control clay swelling

    Energy Technology Data Exchange (ETDEWEB)

    Slobod, R L; Beiswanger, J P.G.

    1968-01-01

    The injection of water to displace oil is one of the main methods used to increase oil recovery. High injection rates are generally desired, and in some cases the flood will not be economic unless high rates are maintained. The presence of clays which swell in the presence of water offers a complication to the problem of maintaining adequate injectivity. In the course of this study it was observed that certain polymers, when present in dilute concentrations in the water, had the ability to reduce the response of these clays to fresh water. Two polymers, one an anionic and the other nonionic, were found to be very effective in controlling the clays present in Berea cores. Successful control of clay swelling was obtained by use of solutions containing as little as 1.0 ppM of polymer, but at this low concentration appreciable volumes of treating solution were required. These results suggest that some minimum amount of polymer must be adsorbed to prevent clay swelling. In Berea sandstone this minimum amount appeared to be of the order of 0.03 mg per cc of pore space. A series of tests made using 10.0 ppM polymer showed that the polymer could be made through the porous system in which 0.066 per mg of polymer was adsorbed per cc of pore space.

  3. Clay and concrete brick

    CSIR Research Space (South Africa)

    Dlamini, MN

    2014-03-01

    Full Text Available Brick is one of the most used and versatile building materials in use today. Bricks can be defined as modular units connected by mortar in the formation of a building system or product. Commonly the word brick is used to refer to clay bricks, which...

  4. Clay matrix voltammetry

    International Nuclear Information System (INIS)

    Perdicakis, Michel

    2012-01-01

    Document available in extended abstract form only. In many countries, it is planned that the long life highly radioactive nuclear spent fuel will be stored in deep argillaceous rocks. The sites selected for this purpose are anoxic and satisfy several recommendations as mechanical stability, low permeability and low redox potential. Pyrite (FeS 2 ), iron(II) carbonate, iron(II) bearing clays and organic matter that are present in very small amounts (about 1% w:w) in soils play a major role in their reactivity and are considered today as responsible for the low redox potential values of these sites. In this communication, we describe an electrochemical technique derived from 'Salt matrix voltammetry' and allowing the almost in-situ voltammetric characterization of air-sensitive samples of soils after the only addition of the minimum humidity required for electrolytic conduction. Figure 1 shows the principle of the developed technique. It consists in the entrapment of the clay sample between a graphite working electrode and a silver counter/quasi-reference electrode. The sample was previously humidified by passing a water saturated inert gas through the electrochemical cell. The technique leads to well-defined voltammetric responses of the electro-active components of the clays. Figure 2 shows a typical voltammogram relative to a Callovo-Oxfordian argillite sample from Bure, the French place planned for the underground nuclear waste disposal. During the direct scan, one can clearly distinguish the anodic voltammetric signals for the oxidation of the iron (II) species associated with the clay and the oxidation of pyrite. The reverse scan displays a small cathodic signal for the reduction of iron (III) associated with the clay that demonstrates that the majority of the previously oxidized iron (II) species were transformed into iron (III) oxides reducible at lower potentials. When a second voltammetric cycle is performed, one can notice that the signal for iron (II

  5. Physical Properties of Latvian Clays

    OpenAIRE

    Jurgelāne, I; Stepanova, V; Ločs, J; Mālers, J; Bērziņa-Cimdiņa, L

    2012-01-01

    Physical and chemical properties of clays mostly depends on its mineral and chemical composition, particle size and pH value. The mutual influence of these parameters is complex. Illite is the most abundant clay mineral in Latvia and usually used in building materials and pottery. The viscosity and plasticity of Latvian clays from several deposits were investigated and correlated with mineral composition, particle size and pH value. Fractionated and crude clay samples were used. The p...

  6. Mud peeling and horizontal crack formation in drying clays

    KAUST Repository

    Style, Robert W.

    2011-03-01

    Mud peeling is a common phenomenon whereby horizontal cracks propagate parallel to the surface of a drying clay. Differential stresses then cause the layer of clay above the crack to curl up to form a mud peel. By treating the clay as a poroelastic solid, we analyze the peeling phenomenon and show that it is caused by the gradient in tensile stress at the surface of the clay, analogously to the spalling of thermoelastic materials. For a constant water evaporation rate at the clay surface we derive equations for the depth of peeling and the time of peeling as functions of the evaporation rate. Our model predicts a simple relationship between the radius of curvature of a mud peel and the depth of peeling. The model predictions are in agreement with the available experimental data. Copyright 2011 by the American Geophysical Union.

  7. Study and development of nanocomposites PBT/bentonite clay treated by ionizing radiation: preparation and characterization; Estudo e desenvolvimento de nanocompositos PBT/argila bentonita tratados por radiacao ionizante: preparacao e caracterizacao

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, Mariana do Nascimento

    2014-07-01

    This work describes the preparation and characterization of composites based on poly (butylene terephthalate) - PBT and brazilian modified clay prepared by the melt intercalation. PBT nanocomposites with 3 and 5 % by weight of organically modified clay, by the addition of a quaternary ammonium salt, were prepared by extrusion using a twin-screw extruder machine. After the extrusion process, the materials were injected to obtain specimens tests samples for the characterization tests. Part of the specimens samples were irradiated using an electron beam accelerator with 1.5 MeV at room temperature in the presence of air. Samples of pure PBT and irradiated and non-irradiated nanocomposites were characterized by mechanical tests of tensile, flexural and impact, heat distortion temperature (HDT), X - ray diffraction (XRD), scanning electron microscopy (SEM), melt flow index (MFI) thermogravimetry (TG) and differential scanning calorimetry (DSC) and the correlation between the properties was discussed. The results showed that the addition of clay, in both percentages, promoted an increase greater than 50 % in tensile strength at break and a gain of around 35% in heat distortion temperature when compared to the pure polymer. The treatment with ionizing radiation of electron beam at the doses used in this study showed no significant changes in material properties. (author)

  8. Clay Animals and Their Habitats

    Science.gov (United States)

    Adamson, Kay

    2010-01-01

    Creating clay animals and their habitats with second-grade students has long been one of the author's favorite classroom activities. Students love working with clay and they also enjoy drawing animal homes. In this article, the author describes how the students created a diorama instead of drawing their clay animal's habitat. This gave students…

  9. Clay membrane made of natural high plasticity clay

    DEFF Research Database (Denmark)

    Foged, Niels; Baumann, Jens

    1998-01-01

    Leachate containment in Denmark has through years been regulated by the DIF Recommendation for Sanitary Landfill Liners (DS/R 466). It states natural clay deposits may be used for membrane material provided the membrane and drainage system may contain at least 95% of all leachate created throughout...... ion transport as well as diffusion.Clay prospection for clays rich in smectite has revealed large deposits of Tertiary clay of very high plasticity in the area around Rødbyhavn on the Danish island Lolland. The natural clay contains 60 to 75% smectite, dominantly as a sodium-type. The clay material...... has been evaluated using standardised methods related to mineralogy, classification, compaction and permeability, and initial studies of diffusion properties have been carried out. Furthermore, at a test site the construction methods for establishing a 0.15 to 0.3m thick clay membrane have been tested...

  10. Clay membrane made of natural high plasticity clay:

    DEFF Research Database (Denmark)

    Foged, Niels; Baumann, Jens

    1999-01-01

    Leachate containment in Denmark has throughout the years been regulated by the DIF Recommendation for Sanitary Landfill Liners (DS/R4669. It states that natural clay deposits may be used as membrane material provided the membrane and drainage system contains at least 95% of all leachate created...... into account advective ion transport as well as diffusion. Clay prospecting for clays rich in smectite has revealed large deposits of Tertiary clay of very high plasticity in the area around Rødbyhavn on the Danish island of Lolland. The natural clay contains 60-75% smectite, dominantly as a sodium......-type. The clay material has been evaluated using the standardized methods related to mineralogy, classification, compaction and permeability, and initial studies of diffusion properties have been carried out. Furthermore, at a test site the construction methods for establishing a 0.15-0.3 m thick clay membrane...

  11. Modification of a Brazilian smectite clay with different quaternary ammonium salts

    Directory of Open Access Journals (Sweden)

    Maria Flávia Delbem

    2010-01-01

    Full Text Available In this work, a smectite clay from the State of Paraiba, Brazil, was treated with six different types of ammonium salts, which is an usual method to enhance the affinity between the clay and polymer for the preparation of nanocomposites. The clays, before and after modification, were characterized by X ray diffraction. The conformation of the salts within the platelets of the clay depended on the number of long alkyl chains of the salt. The thermal stability of the clays was also studied. The ammonium salts thermal decomposition was explained in light of their position within the organoclays.

  12. Morphologic characterization for XRD and TEM of polyamide 6 and 66 nanocomposites with bentonite regional clay

    International Nuclear Information System (INIS)

    Leite, Amanda M.D.; Medeiros, Vanessa da N.; Maia, Larissa F.; Araujo, Edcleide M.; Lira, Helio L.

    2009-01-01

    Polyamide 6 and 66 nanocomposites with clay consisting of silicates layer from Paraiba were produced. The clay was modified being used the quaternary salt of ammonium Cetremide, this so there is a better interaction of the clay with polymeric matrix. The clay without treatment (MMT) and treated clay was evaluated by XRD that showed the insertion of the salt molecules into silicates layer. The nanocomposites were obtained from polyamide 6 and 66 were verified that these presented morphological structure composed of exfoliated/partially exfoliated, analyzed by XRD and TEM. (author)

  13. Crude oil polycyclic aromatic hydrocarbons removal via clay-microbe-oil interactions: Effect of acid activated clay minerals.

    Science.gov (United States)

    Ugochukwu, Uzochukwu C; Fialips, Claire I

    2017-07-01

    Acid treatment of clay minerals is known to modify their properties such as increase their surface area and surface acidity, making them suitable as catalysts in many chemical processes. However, the role of these surface properties during biodegradation processes of polycyclic aromatic hydrocarbons (PAHs) is only known for mild acid (0.5 M Hydrochloric acid) treated clays. Four different clay minerals were used for this study: a montmorillonite, a saponite, a palygorskite and a kaolinite. They were treated with 3 M hydrochloric acid to produce acid activated clay minerals. The role of the acid activated montmorillonite, saponite, palygorskite and kaolinite in comparison with the unmodified clay minerals in the removal of PAHs during biodegradation was investigated in microcosm experiments. The microcosm experiments contained micro-organisms, oil, and clays in aqueous medium with a hydrocarbon degrading microorganism community predominantly composed of Alcanivorax spp. Obtained results indicated that acid activated clays and unmodified kaolinite did not enhance the biodegradation of the PAHs whereas unmodified montmorillonite, palygorskite and saponite enhanced their biodegradation. In addition, unmodified palygorskite adsorbed the PAHs significantly due to its unique channel structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. A Study of Clay-Epoxy Nanocomposites Consisting of Unmodified Clay and Organo Clay

    Directory of Open Access Journals (Sweden)

    Graham Edward

    2006-04-01

    Full Text Available Clay-epoxy nanocomposites were synthesized from DGEBA resin and montmorillonite clay with an in-situ polymerization. One type of untreated clay and two types of organo clay were used to produce the nanocompsoites. The aims of this study were to examine the nanocomposite structure using different tools and to compare the results between the unmodified clay and modified clays as nanofillers. Although diffractogram in reflection mode did not show any apparent peak of both types of materials, the transmitted XRD (X-Ray Difraction graphs, DSC (Differential Scanning Calorimeter analysis and TEM (Transmission Electron Microscope images revealed that the modified clay-epoxy and unmodified clay-epoxy provides different results. Interestingly, the micrographs showed that some of the modified clay layers possessed non-exfoliated layers in the modified clay-epoxy nanocomposites. Clay aggregates and a hackle pattern were found from E-SEM images for both types of nanocomposite materials. It is shown that different tools should be used to determine the nanocomposite structure.

  15. Modification of UHMWPE membrane with a PE/clay/PE-G-MA nano composite film to treat oily effluents; Modificacao de membrana de PEUAPM com filme nanocomposito de PEAD/argila/PE-G-MA para o tratamento de efluentes oleosos

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Suelem S.L.; Silva, Caio M.B.; Leal, Tania L; Carvalho, Laura H; Costa, Anna R.M. [Universidade Federal de Campina Grande (UFCG), PB (Brazil)], e-mail: tanlucleal@yahoo.com.br

    2011-07-01

    Interest in techniques of surface modification is evinced by the large number of studies in recent decades. In this work the internal surfaces of polymeric membranes of ultra high molecular weight polyethylene (UHMWPE) were modified by impregnation of HDPE/organoclay/PE-g-MA nanocomposite film. The addition of PE-g-MA aims to increase polymer/clay interaction and to control and/or modify surface characteristics of UHMWPE membranes, such as permeability and pore size, so as to make the membranes more efficient and/or appropriate for effluent treatment, more specifically in the treatment of oil contaminated water. The films were analyzed by infrared spectroscopy (FTIR), the modified membranes were characterized by scanning electron microscopy (SEM) and their performance (permeate flux and selectivity) were measured using distilled water and an oil in water dispersion. (author)

  16. Research of Deformation of Clay Soil Mixtures Mixtures

    OpenAIRE

    Romas Girkontas; Tadas Tamošiūnas; Andrius Savickas

    2014-01-01

    The aim of this article is to determine clay soils and clay soils mixtures deformations during drying. Experiments consisted from: a) clay and clay mixtures bridges (height ~ 0,30 m, span ~ 1,00 m); b) tiles of clay and clay, sand and straw (height, length, wide); c) cylinders of clay; clay and straw; clay, straw and sand (diameter; height). According to the findings recommendations for clay and clay mixtures drying technology application were presented. During the experiment clay bridge bear...

  17. Structure and mechanical properties of polyamide 6/Brazilian clay nanocomposites

    Directory of Open Access Journals (Sweden)

    Amanda Melissa Damião Leite

    2009-06-01

    Full Text Available Recent interest in polymer/organoclays nanocomposites systems is motivated by the possibility of achieving enhanced properties and added functionality at lower clay loading as compared to conventional micron size fillers. By adding montmorillonite clay to polyamide 6 increases the Young modulus, yield strength and also improves barrier properties. In this work, nanocomposites of polyamide 6 with montmorillonite clay were obtained. The clay was chemically modified with three different quaternary ammonium salts such as: Dodigen, Genamin and Cetremide. In this case, a dispersion of Na-MMT was stirred and a salt equivalent to 1:1 of cation exchange capacity (CEC of Na-MMT was added to the dispersion. The montmorillonite clay (untreated and treated by ammonium salts and nanocomposites were characterized by X ray diffractions. Also the nanocomposites were characterized by transmission electron microscopy and mechanical properties. The results indicated that all the quaternary ammonium salts were intercalated between the layers of clay, leading to an expansion of the interlayer spacing. The obtained nanocomposites showed better mechanical properties when compared to polyamide 6. The clay acted as reinforcing filler, increasing the rigidity of nanocomposites and decreasing its ductility.

  18. Influence of clay, surfactant and presence of dispersant in the non-aqueous fluids rheology

    International Nuclear Information System (INIS)

    Gomes, N.L.; Guedes, I.C.; Menezes, R.R.; Campos, L.F.A.; Ferreira, H.S.

    2012-01-01

    The bentonite clay used as a thickening agent in production of non-aqueous fluids and can not be used without a prior treatment to their organic surfaces become hydrophobic. These treated clays are called organoclays, and are usually obtained by adding, in aqueous solution, a quaternary ammonium salt. This work makes a detailed study of the variables involved in the dispersion of the bentonite clays in organophilization process, as well, the type of clay, type of surfactant and the presence of dispersant. It was observed this study that the process variables involved in the dispersion of the clays and organophilization, observed through characterization, have low influence on the peaks related to interplanar basal distance caused by the incorporation of the surfactant and bentonite clays been influential the type of clay and surfactant and the presence of sodium as dispersant agent, on the rheological properties. (author)

  19. Influence of clay and surfactant content in non-aqueous fluid rheology

    International Nuclear Information System (INIS)

    Guedes, I.C.; Gomes, N.L.; Menezes, R.R.; Campos, L.F.A.; Ferreira, H.S.

    2012-01-01

    The bentonite clay used as viscosity agent in the production of non-aqueous fluids cannot be used without organic treatment for their surfaces to become hydrophobic. These clays are called organophilic clays, and are generally obtained by adding, in an aqueous way, ionic or a nonionic surfactant. Recent studies of the variables involved in the dispersion of bentonite clays and in the process of organophilization, showed their lack of influence. This work aims to study the influence of clay content and surfactants on the rheology of nonaqueous fluids. To this end, the clays were treats and characterized, evidencing the incorporation of the surfactant, and then formulated non-aqueous fluids, following PETROBRAS standards, being possible to verify the influence of clay content and surfactant both from the point of view as the characterizing and rheological behavior. (author)

  20. Creep in buffer clay

    International Nuclear Information System (INIS)

    Pusch, R.; Adey, R.

    1999-12-01

    The study involved characterization of the microstructural arrangement and molecular forcefields in the buffer clay for getting a basis for selecting suitable creep models. It is concluded that the number of particles and wide range of the particle bond spectrum require that stochastical mechanics and thermodynamics will be considered and they are basic to the creep model proposed for predicting creep settlement of the canisters. The influence of the stress level on creep strain of MX-80 clay is not well known but for the buffer creep is approximately proportional to stress. Theoretical considerations suggest a moderate impact for temperatures up to 90 deg C and this is supported by model experiments. It is believed that the assumption of strain being proportional to temperature is conservative. The general performance of the stochastic model can be illustrated in principle by use of visco-elastic rheological models implying a time-related increase in viscosity. The shear-induced creep settlement under constant volume conditions calculated by using the proposed creep model is on the order of 1 mm in ten thousand years and up to a couple of millimeters in one million years. It is much smaller than the consolidation settlement, which is believed to be on the order of 10 mm. The general conclusion is that creep settlement of the canisters is very small and of no significance to the integrity of the buffer itself or of the canisters

  1. Euroclay 95. Clays and clay materials sciences. Book of abstracts

    International Nuclear Information System (INIS)

    Elsen, A.; Grobet, P.; Keung, M.; Leeman, H.; Schoonheydt, R.; Toufar, H.

    1995-01-01

    The document contains the abstracts of the invited lecturers (18) and posters (247) presented at EUROCLAY '95. Clays and clay materials sciences. 13 items (4 from the invited lecturers and 12 from posters) have been considered within the INIS Subject Scope and indexed separately

  2. Euroclay 95. Clays and clay materials sciences. Book of abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Elsen, A; Grobet, P; Keung, M; Leeman, H; Schoonheydt, R; Toufar, H [eds.

    1995-08-20

    The document contains the abstracts of the invited lecturers (18) and posters (247) presented at EUROCLAY `95. Clays and clay materials sciences. 13 items (4 from the invited lecturers and 12 from posters) have been considered within the INIS Subject Scope and indexed separately.

  3. Influence of clay mineralogy on clay based ceramic products

    International Nuclear Information System (INIS)

    Radzali Othman; Tuan Besar Tuan Sarif; Zainal Arifin Ahmad; Ahmad Fauzi Mohd Noor; Abu Bakar Aramjat

    1996-01-01

    Clay-based ceramic products can either be produced directly from a suitable clay source without the need further addition or such products can be produced from a ceramic body formulated by additions of other raw materials such as feldspar and silica sand. In either case, the mineralogical make-up of the clay component plays a dominating role in the fabrication and properties of the ceramic product. This study was sparked off by a peculiar result observed in one of five local ball clay samples that were used to reformulate a ceramic body. Initial characterisation tests conducted on the clays indicated that these clays can be classified as kaolinitic. However, one of these clays produced a ceramic body that is distinctively different in terms of whiteness, smoothness and density as compared to the other four clays. Careful re-examination of other characterisation data, such as particle size distribution and chemical analysis, failed to offer any plausible explanation. Consequently, the mineralogical analysis by x-ray diffraction was repeated by paying meticulous attention to specimen preparation. Diffraction data for the clay with anomalous behaviour indicated the presence of a ∼ 10A peak that diminished when the same specimen was re-tested after heating in an oven at 12O degree C whilst the other four clays only exhibit the characteristic kaolinite (Al sub 2 O sub 3. 2SiO sub 2. 2H sub 2 0) and muscovite peaks at ∼ 7A and ∼ 10A before and after heat treatment. This suggests the presence of the mineral halloysite (A1 sub 2 0 sub 3. 2SiO sub 2.4H sub 2 0) in that particular clay. This difference in mineralogy can be attributed to account for the variations in physical properties of the final product. Consequently, this paper reviews in general the precautionary measures that must be adhered to during any mineralogical investigation of clay minerals or clay-based materials. The common pitfalls during specimen preparation, machine settings and interpretation of

  4. Study of methods for electrical modification of a clay suspension

    Energy Technology Data Exchange (ETDEWEB)

    Karimov, R A; Kudaktina, T T; Parpiyev, T R

    1982-01-01

    As a result of the conducted experiments it was established that the viscosity and maximum static shear stress of the drilling muds prepared on electrically treated water increases 2-3-fold as compared to the muds prepared on standard water. This is explained by the fact that the unipolar treatment results in deep change in the water structure. Under the influence of the electrical current, there is activation, rise in the electrical conductivity, decrease in surface tension, considerable rise in the pH value, etc. The output of clay mud increases 1.5-fold in the clay suspension that is prepared on electrically treated water.

  5. Encapsulation of Clay Platelets inside Latex Particles

    NARCIS (Netherlands)

    Voorn, D.J.; Ming, W.; Herk, van A.M.; Fernando, R.H.; Sung, Li-Piin

    2009-01-01

    We present our recent attempts in encapsulating clay platelets inside latex particles by emulsion polymerization. Face modification of clay platelets by cationic exchange has been shown to be insufficient for clay encapsulation, leading to armored latex particles. Successful encapsulation of

  6. Thixotropic Properties of Latvian Illite Containing Clays

    OpenAIRE

    Lakevičs, Vitālijs; Stepanova, Valentīna; Niedra, Santa; Dušenkova, Inga; Ruplis, Augusts

    2015-01-01

    Thixotropic properties of Latvian Devonian and Quaternary clays were studied. Dynamic viscosity of the water clay suspensions were measured with a rotating viscometer. Influence of concentration, pH and modifiers on the thixotropic clay properties was analyzed. It was found that Latvian clays have thixotropic properties. Stability of clay suspensions is described with the thixotropy hysteresis loop. Increasing the speed of the viscometer rotation, dynamic viscosity of the clay suspension decr...

  7. Viscosity and Plasticity of Latvian Illite Clays

    OpenAIRE

    Jurgelāne, I; Vecstaudža, J; Stepanova, V; Mālers, J; Bērziņa-Cimdiņa, L

    2012-01-01

    Due to viscosity and plasticity, clays and clay minerals are used in civil engineering, pottery and also in cosmetics and medicine as thickening agents and emulsion and suspension stabilizers. The rheological properties of clay suspensions are complex. Mostly it is an interaction between mineral composition, clay particle size and pH value and also depends on clay minerals. Clay-water suspension is non-Newtonian fluid showing thixotropic and pseudoplastic properties. Results showed that plast...

  8. Thermal volume changes in clays and clay-stones

    International Nuclear Information System (INIS)

    Delage, P.; Sulem, J.; Mohajerani, M.; Tang, A.M.; Monfared, M.

    2012-01-01

    Document available in extended abstract form only. The disposal of high activity exothermic radioactive waste at great depth in clay host rocks will induce a temperature elevation that has been investigated in various underground research laboratories in Belgium, France and Switzerland through in-situ tests. Thermal effects are better known in clays (in particular Boom clay) than in clay-stone (e.g. Opalinus clay and Callovo-Oxfordian clay-stone). In terms of volume changes, Figure 1 confirms the findings of Hueckel and Baldi (1990) that volume changes depend on the over-consolidation ratio (OCR) of the clay. In drained conditions, normally consolidated clays exhibit plastic contraction when heated, whereas over-consolidated clay exhibit elastic dilation. The nature of thermal volume changes in heated clays obviously has a significant effect on thermally induced pore pressures, when drainage is not instantaneous like what occurs in-situ. Compared to clays, the thermal volume change behaviour of clay-stones is less well known than that of clays. clay-stone are a priori suspected to behave like over-consolidated clays. In this paper, a comparison of recent results obtained in the laboratory on the drained thermal volume changes of clay-stones is presented and discussed. It is difficult to run drained mechanical tests in clay-stones like the Opalinus clay and the Callovo-Oxfordian clay-stone because of their quite low permeability (10 -12 - 10 -13 m/s). This also holds true for thermal tests. Due to the significant difference in thermal expansion coefficient between minerals and water, it is necessary to adopt very slow heating rate (0.5 - 1 C/h) to avoid any thermal pressurization. To do so, a new hollow cylinder apparatus (100 mm external diameter, 60 mm internal diameter) with lateral drainages reducing the drainage length to half the sample thickness (10 mm) has been developed (Monfared et al. 2011). The results of a drained cyclic thermal test carried out on

  9. Catalytic Wastewater Treatment Using Pillared Clays

    Science.gov (United States)

    Perathoner, Siglinda; Centi, Gabriele

    After introduction on the use of solid catalysts in wastewater treatment technologies, particularly advanced oxidation processes (AOPs), this review discussed the use of pillared clay (PILC) materials in three applications: (i) wet air catalytic oxidation (WACO), (ii) wet hydrogen peroxide catalytic oxidation (WHPCO) on Cu-PILC and Fe-PILC, and (iii) behavior of Ti-PILC and Fe-PILC in the photocatalytic or photo-Fenton conversion of pollutants. Literature data are critically analyzed to evidence the main direction to further investigate, in particularly with reference to the possible practical application of these technologies to treat industrial, municipal, or agro-food production wastewater.

  10. Organosilane grafted acid-activated beidellite clay for the removal of non-ionic alachlor and anionic imazaquin

    International Nuclear Information System (INIS)

    Paul, Blain; Martens, Wayde N.; Frost, Ray L.

    2011-01-01

    Clay adsorbents were prepared via two-step method to remove nonionic alachlor and anionic imazaquin herbicides from water. Firstly, layered beidellite clay, a member of smectite family, was treated with acid in hydrothermal process; secondly, common silane coupling agents, 3-chloro-propyl trimethoxysilane or triethoxy silane, were grafted on the acid treated samples to prepare adsorbent materials. The organically modified clay samples were characterized by powder X-ray diffraction, N 2 gas adsorption, and FTIR spectroscopy. It was found that the selective modification of clay samples displayed higher adsorption capacity for herbicides compared with acid activated clay. And the amount of adsorption is increased with increasing the grafting amount of silane groups. Clay grafted with 3-chloro-propyl trimethoxysilane is an excellent adsorbent for both alachlor and imazaquin but triethoxy (octyl) silane grafted clay is more efficient only for alachlor removal.

  11. Strength Properties of Aalborg Clay

    DEFF Research Database (Denmark)

    Iversen, Kirsten Malte; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust

    glacial time are characterised by the absence of this mussel. These deposits are named Aalborg Clay and Aalborg Sand. In the city of Aalborg, a fill layer superposes Aalborg Clay. This layer is at some places found to be 6m thick. This fill layer does not provide sufficient bearing capacity, which has...... resulted in many damaged buildings in Aalborg. To provide sufficient bearing capacity it is therefore necessary either to remove the fill or to construct the building on piles. Both methods imply that the strength of Aalborg Clay is important for the construction. This paper evaluates the strength...

  12. Geochemical of clay formations : study of Spanish clay REFERENCE

    International Nuclear Information System (INIS)

    Turrero, M. J.; Pena, J.

    2003-01-01

    Clay rocks are investigated in different international research programs in order to assess its feasibility for the disposal of high level radioactive wastes. This is because different sepcific aspects: they have low hydraulic conductivity (10''-11-10''-15 m/s), a high sorption capacity, self-sealing capacity of facults and discontinuities and mechanical resistance. Several research programs on clay formations are aimed to study the chemistry of the groundwater and the water-rock reactions that control it: e. g. Boom Clay (Mol, Belgium), Oxford Clay /Harwell, United Kingdom), Toarcian Clay (Tournemire, France), Palfris formation (Wellenberg, Switzerland), Opalinus Clay (Bure, France). Based on these studies, considerable progress in the development of techniques for hydrologic, geochemical and hydrogeochemical characterization of mudstones has been accomplished (e. g. Beaufais et al. 1994, De Windt el al. 1998. Thury and Bossart 1999, Sacchi and Michelot 2000) with important advances in the knowledge of geochemical process in these materials (e. g. Reeder et al. 1993, Baeyens and Brandbury 1994, Beaucaire et al. 2000, Pearson et al., 2003).Furtermore, geochemical modeling is commonly used to simulate the evolution of water chemistry and to understand quantitatively the processes controlling the groundwater chemistry (e. g. Pearson et al. 1998, Tempel and Harrison 2000, Arcos et al., 2001). The work presented here is part of a research program funded by Enresa in the context of its R and D program. It is focused on the characterization of a clay formation (reference Argillaceous Formation, RAF) located within the Duero Basin (north-centralSpain). The characterisation of th ephysical properties,, fluid composition, mineralogy, water-rock reaction processes, geochemical modelling and sorption properties of the clays from the mentioned wells is the main purpose of this work. (Author)

  13. Comprehensive review of geosynthetic clay liner and compacted clay liner

    Science.gov (United States)

    Shankar, M. Uma; Muthukumar, M.

    2017-11-01

    Human activity inevitably produces waste materials that must be managed. Some waste can be reused. However many wastes that cannot be used beneficially must be disposed of ensuring environmental safety. One of the common methods of disposal is landfilling. The most common problems of the landfill site are environmental degradation and groundwater contamination caused by leachate produced during the decomposition process of organic material and rainfall. Liner in a landfill is an important component which prevent leachate migration and prevent groundwater contamination. Earthen liners have been widely used to contain waste materials in landfill. Liners and covers for municipal and hazardous waste containment facilities are often constructed with the use of fine-grained, low plasticity soils. Because of low permeability geosynthetic clay liners and compacted clay liners are the main materials used in waste disposal landfills. This paper summaries the important geotechnical characteristics such as hydraulic conductivity, liquid limit and free swell index of geosynthetic clay liner and compacted clay liner based on research findings. This paper also compares geosynthetic clay liner and compacted clay liner based on certain criteria such as thickness, availability of materials, vulnerability to damage etc.

  14. {alpha}-Pinene conversion by modified-kaolinitic clay

    Energy Technology Data Exchange (ETDEWEB)

    Volzone, C. [CETMIC-Centro de Tecnologia de Recursos Minerales y Ceramica-(CONICET-CIC), C.C. 49, Cno. Centenario y 506 (1897) M.B. Gonnet, Prov., Buenos Aires (Argentina)]. E-mail: volzcris@netverk.com.ar; Masini, O. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina); Comelli, N.A. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina); Grzona, L.M. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina); Ponzi, E.N. [CINDECA (CONICET-UNLP) calle 47 No. 257 (1900) La Plata, Prov., Buenos Aires (Argentina); Ponzi, M.I. [INTEQUI (CONICET-UNSL), Facultad de Ingenieria y Ciencias Economico Sociales, 25 de Mayo 384, V. Mercedes, Prov., San Luis (Argentina)

    2005-10-15

    The isomerization of {alpha}-pinene using natural kaolinitic clay before and after different treatments was studied in this work. The kaolinite is a clay material constituted by phyllosilicate 1:1 layer (one sheet of tetrahedral silicon and one sheet of octahedral alumina). The clay was treated at different times using 6.0 N solution of sulfuric acid previous heating to 500 or 700 K. The materials were characterized by X-ray diffraction, by chemical analyses and acidity measurements. The catalytic reactions were carried out at 373 K in a reactor batch with condenser and stirrer. Samples were taken at regular intervals, and reactants and products were quantitatively analyzed with a gas chromatograph after separation of the individual compounds. Conversions of alpha pinene between 67 and 94%, and selectivities in camphene and in limonene of 65 and 23%, respectively, were obtained with the clay treated at different conditions. The structural and textural changes of the clay by the treatments influenced on catalytic reactions.

  15. α-Pinene conversion by modified-kaolinitic clay

    International Nuclear Information System (INIS)

    Volzone, C.; Masini, O.; Comelli, N.A.; Grzona, L.M.; Ponzi, E.N.; Ponzi, M.I.

    2005-01-01

    The isomerization of α-pinene using natural kaolinitic clay before and after different treatments was studied in this work. The kaolinite is a clay material constituted by phyllosilicate 1:1 layer (one sheet of tetrahedral silicon and one sheet of octahedral alumina). The clay was treated at different times using 6.0 N solution of sulfuric acid previous heating to 500 or 700 K. The materials were characterized by X-ray diffraction, by chemical analyses and acidity measurements. The catalytic reactions were carried out at 373 K in a reactor batch with condenser and stirrer. Samples were taken at regular intervals, and reactants and products were quantitatively analyzed with a gas chromatograph after separation of the individual compounds. Conversions of alpha pinene between 67 and 94%, and selectivities in camphene and in limonene of 65 and 23%, respectively, were obtained with the clay treated at different conditions. The structural and textural changes of the clay by the treatments influenced on catalytic reactions

  16. Clay fraction mineralogy of a Cambisol in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Anastacio, A. S.; Fabris, J. D., E-mail: jdfabris@ufmg.br [Federal University of Minas Gerais, Campus - Pampulha, Department of Chemistry (Brazil); Stucki, J. W. [Department of Natural Resources and Environmental Sciences (United States); Coelho, F. S.; Pinto, I. V. [Federal University of Minas Gerais, Campus - Pampulha, Department of Chemistry (Brazil); Viana, J. H. M. [Embrapa Milho e Sorgo (Brazil)

    2005-11-15

    Clay minerals having a 2:1 (tetrahedral:octahedral sheet) structure may be found in strongly weathering soils only if the local pedo-climatic environment prevents them from further weathering to other minerals such as iron oxides. The clay minerals impart important chemical properties to soils, in part by virtue of changes in the redox state of iron in their crystal structures. Knowing the chemical nature of soil clays is a first step in evaluating their potential reactivity with other soil constituents and processes, such as the chemical decomposition of organic substrates to be potentially used in environmental remediation. The purpose of this work was to characterize the iron oxides and iron-bearing clay minerals from a B horizon of a Cambisol developed on tuffite in the State of Minas Gerais, Brazil, using chemical analysis, powder X-ray diffraction, Moessbauer spectroscopy, and thermal analysis. The iron oxides of this NaOH-treated clay-fraction were found to contain mainly maghemite ({gamma}Fe{sub 2}O{sub 3}) and superparamagnetic goethite ({alpha}FeOOH). Kaolinite (Al{sub 2}Si{sub 2}O{sub 5}(OH){sub 4}), smectite, and minor portions of anatase (TiO{sub 2}) were identified in the CBD-treated sample.

  17. Clay fraction mineralogy of a Cambisol in Brazil

    International Nuclear Information System (INIS)

    Anastacio, A. S.; Fabris, J. D.; Stucki, J. W.; Coelho, F. S.; Pinto, I. V.; Viana, J. H. M.

    2005-01-01

    Clay minerals having a 2:1 (tetrahedral:octahedral sheet) structure may be found in strongly weathering soils only if the local pedo-climatic environment prevents them from further weathering to other minerals such as iron oxides. The clay minerals impart important chemical properties to soils, in part by virtue of changes in the redox state of iron in their crystal structures. Knowing the chemical nature of soil clays is a first step in evaluating their potential reactivity with other soil constituents and processes, such as the chemical decomposition of organic substrates to be potentially used in environmental remediation. The purpose of this work was to characterize the iron oxides and iron-bearing clay minerals from a B horizon of a Cambisol developed on tuffite in the State of Minas Gerais, Brazil, using chemical analysis, powder X-ray diffraction, Moessbauer spectroscopy, and thermal analysis. The iron oxides of this NaOH-treated clay-fraction were found to contain mainly maghemite (γFe 2 O 3 ) and superparamagnetic goethite (αFeOOH). Kaolinite (Al 2 Si 2 O 5 (OH) 4 ), smectite, and minor portions of anatase (TiO 2 ) were identified in the CBD-treated sample.

  18. Bentonite clay purification for development of polymeric nan composites using a single screw extruder

    International Nuclear Information System (INIS)

    Carvalho, Ana C.M. de; Ito, Edson N.; Costa, Maria C.B.; Barbosa, Maria I.R.

    2011-01-01

    In this work, a bentonite clay rich in montmorillonite was purified and chemical treat to be used in the development of poly (methyl methacrylate) /clay nanocomposites via melting processes. After the clay treatment and purification, a masterbatch with 25% clay and 75% PMMA was produced by solution technique, using acetone as solvent. For produce samples with 2.5% clay, the masterbatch along with pure polymer were added and mixed in single screw extruder with a diameter of 16 mm and W/D 26. X-rays diffractometry (XRD) and X-rays fluorescence (XRF). Tests were performed to evaluate and characterizing the bentonite clay used in the development of this work and differential scanning calorimetry (DSC) tests were performed to evaluate changes in the thermal properties of the nanocomposites produced. (author)

  19. Novel applications of locally sourced montmorillonite (MMT) clay as ...

    African Journals Online (AJOL)

    This work explores the application of a locally sourced raw material, montmorillonite (MMT) clay, as a disintegrant in the formulation of an analgesic pharmaceutical product - paracetamol. The raw MMT was refined and treated with 0.IM NaCl to yield sodium montmorillonite (NaMMT) and the powder properties established in ...

  20. Wave liquefaction in soils with clay content

    DEFF Research Database (Denmark)

    Kirca, Özgür; Sumer, B. Mutlu; Fredsøe, Jørgen

    2012-01-01

    The paper presents the results of an experimental study of the influence of clay content (in silt-clay and sand-clay mixtures) on liquefaction beneath progressive waves. The experiments showed that the influence of clay content is very significant. Susceptibility of silt to liquefaction is increa...

  1. What makes a natural clay antibacterial?

    Science.gov (United States)

    Williams, Lynda B.; Metge, David W.; Eberl, Dennis D.; Harvey, Ronald W.; Turner, Amanda G.; Prapaipong, Panjai; Port-Peterson, Amisha T.

    2011-01-01

    Natural clays have been used in ancient and modern medicine, but the mechanism(s) that make certain clays lethal against bacterial pathogens has not been identified. We have compared the depositional environments, mineralogies, and chemistries of clays that exhibit antibacterial effects on a broad spectrum of human pathogens including antibiotic resistant strains. Natural antibacterial clays contain nanoscale (2+ solubility.

  2. Thermal Behaviour of clay formations

    International Nuclear Information System (INIS)

    Tassoni, E.

    1985-01-01

    The programme carried out by ENEA to model the thermal-hydraulic-mechanical behaviour of the clay formations and to measure, in situ and in laboratory, the thermal properties of these rocks, is presented. An in situ heating experiment has been carried out in an open clay quarry in the area of Monterotondo, near Rome. The main goal of the experiment was to know the temperature field and the thermal effects caused by the high level radioactive waste disposed of in a clayey geological formation. The conclusions are as follows: - the thermal conduction codes are sufficiently accurate to forecast the temperature increases caused in the clay by the dissipation of the heat generated by high level radioactive waste; - the thermal conductivity deduced by means of the ''curve fitting'' method ranges from 0.015 to 0.017 W.cm -1 . 0 C -1 - the temperature variation associated with the transport of clay interstitial water caused by temperature gradient is negligible. A laboratory automated method has been designed to measure the thermal conductivity and diffusivity in clay samples. A review of experimental data concerning thermomechanical effects in rocks as well as results of thermal experiments performed at ISMES on clays are presented. Negative thermal dilation has been found both in the elastic and plastic range under constant stress. Thermoplastic deformation appears ten times greater than the thermoelastic one. A mathematical model is proposed in order to simulate the above and other effects that encompass thermal-elastic-plastic-pore water pressure response of clays at high temperature and effective pressure with undrained and transient drainage conditions. Implementation of the two versions into a finite element computer code is described

  3. Aflatoxin Toxicity Reduction in Feed by Enhanced Binding to Surface-Modified Clay Additives

    Science.gov (United States)

    Jaynes, William F.; Zartman, Richard E.

    2011-01-01

    Animal feeding studies have demonstrated that clay additives, such as bentonites, can bind aflatoxins in ingested feed and reduce or eliminate the toxicity. Bentonite deposits are found throughout the world and mostly consist of expandable smectite minerals, such as montmorillonite. The surfaces of smectite minerals can be treated with organic compounds to create surface-modified clays that more readily bind some contaminants than the untreated clay. Montmorillonites treated with organic cations, such as hexadecyltrimethylammonium (HDTMA) and phenyltrimethylammonium (PTMA), more effectively remove organic contaminants, such as benzene and toluene, from water than untreated clay. Similarly, montmorillonite treated with PTMA (Kd = 24,100) retained more aflatoxin B1 (AfB1) from aqueous corn flour than untreated montmorillonite (Kd = 944). Feed additives that reduced aflatoxin toxicity in animal feeding studies adsorbed more AfB1 from aqueous corn flour than feed additives that were less effective. The organic cations HDTMA and PTMA are considered toxic and would not be suitable for clay additives used in feed or food, but other non-toxic or nutrient compounds can be used to prepare surface-modified clays. Montmorillonite (SWy) treated with choline (Kd = 13,800) and carnitine (Kd = 3960) adsorbed much more AfB1 from aqueous corn flour than the untreated clay (Kd = 944). A choline-treated clay prepared from a reduced-charge, high-charge montmorillonite (Kd = 20,100) adsorbed more AfB1 than the choline-treated high-charge montmorillonite (Kd = 1340) or the untreated montmorillonite (Kd = 293). Surface-modified clay additives prepared using low-charge smectites and nutrient or non-toxic organic compounds might be used to more effectively bind aflatoxins in contaminated feed or food and prevent toxicity. PMID:22069725

  4. Clay dispersibility and soil friability – testing the soil clay-to-carbon saturation concept

    OpenAIRE

    Schjønning, P.; de Jonge, L.W.; Munkholm, L.J.; Moldrup, P.; Christensen, B.T.; Olesen, J.E.

    2011-01-01

    Soil organic carbon (OC) influences clay dispersibility, which affects soil tilth conditions and the risk of vertical migration of clay colloids. No universal lower threshold of OC has been identified for satisfactory stabilization of soil structure. We tested the concept of clay saturation with OC as a predictor of clay dispersibility and soil friability. Soil was sampled three years in a field varying in clay content (~100 to ~220 g kg-1 soil) and grown with different crop rotations. Clay ...

  5. Sorption of radioiodine in organo-clays and -soils

    International Nuclear Information System (INIS)

    Bors, J.

    1990-01-01

    In the framework of investigations on the sorption of radioiodine to natural and artificially altered soil components, a number of clay minerals and natural soils were treated with quaternary alkylammonium ions to replace the exchangeable metal cations. With help of batch experiments the resulting organo-clays were tested with respect to their sorption capability of radioiodine quantified by the distribution ratio (R D -value). Treatment of bentonite, vermiculite and cretaceous clay as well as of samples from natural horizons of chernozem soil with hexadecylpyridinium (HDPY + ) and benzethonium (BE + ) exhibited sorptions rates and amounts, which are several orders of magnitude higher than those of the respective untreated samples. Moderate increases of the R D -values were found after cation exchange with hexadecyltrimethylammonium (HDTMA + ), while the applications of trimethylphenylammonium (TMPA + ) and tetramethylammonium (TMA + ) were ineffective. Considerable sorption of radioiodine was observed with the commercially available Bentone. (orig.)

  6. Sorption of radioiodine in organo-clays and -soils

    Energy Technology Data Exchange (ETDEWEB)

    Bors, J. (Niedersaechsisches Inst. fuer Radiooekologie, Hannover (Germany, F.R.))

    1990-01-01

    In the framework of investigations on the sorption of radioiodine to natural and artificially altered soil components, a number of clay minerals and natural soils were treated with quaternary alkylammonium ions to replace the exchangeable metal cations. With help of batch experiments the resulting organo-clays were tested with respect to their sorption capability of radioiodine quantified by the distribution ratio (R{sub D}-value). Treatment of bentonite, vermiculite and cretaceous clay as well as of samples from natural horizons of chernozem soil with hexadecylpyridinium (HDPY{sup +}) and benzethonium (BE{sup +}) exhibited sorptions rates and amounts, which are several orders of magnitude higher than those of the respective untreated samples. Moderate increases of the R{sub D}-values were found after cation exchange with hexadecyltrimethylammonium (HDTMA{sup +}), while the applications of trimethylphenylammonium (TMPA{sup +}) and tetramethylammonium (TMA{sup +}) were ineffective. Considerable sorption of radioiodine was observed with the commercially available Bentone. (orig.).

  7. Fluoride retention by kaolin clay

    DEFF Research Database (Denmark)

    Kau, P. M. H.; Smith, D. W.; Binning, Philip John

    1997-01-01

    To evaluate the potential effectiveness of kaolin clay liners in storage of fluoride contaminated waste, an experimental study of the sorption and desorption behaviour of fluoride in kaolin clay was conducted. The degree of fluoride sorption by kaolin was found to depend on solution p......H and available fluoride concentration with equilibrium being achieved within 24 h. A site activation process involving the uptake of fluoride was also observed at the initial stages of sorption. This behaviour was attributed to a layer expansion process of the clay during sorption. The maximum fluoride sorption...... capacity was found to be 18.3 meq/100 g at pH 6 and 8.6 meq/100 g at pH 7. A competitive Langmuir sorption isotherm where sorption is dependant on both pH and fluoride concentration is employed to characterise the experimental sorption and desorption data. The sorption and desorption isotherms revealed...

  8. Comparative study by TG and DSC Of membranes polyamide66/bentonite clay nanocomposite; Estudo comparativo por TG e DSC de membranas de nanocompositos poliamida66/argila bentonitica

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, K.M. de; Kojuch, L R; Araujo, E M; Lira, H.L., E-mail: keilamm@ig.com.b [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais; Lima, F [Universidade Estadual da Paraiba (UEPB), Campina Grande, PB (Brazil). Dept. de Quimica

    2010-07-01

    In this study, it was obtained membranes of nanocomposites polyamide66 with 3 and 5% bentonite clay consists of silicates in layers from the interior of Paraiba. The clay was treated with a quaternary ammonium salt in order to make it organophilic. The membranes were prepared by phase inversion technique from the nanocomposites in solution. The clays were characterized by X-ray diffraction (XRD) and thermogravimetry (TG). Also the membranes were characterized by differential scanning calorimetry (DSC) and TG. The XRD and TG confirmed the presence of salt in the clay and thermal stability of the treated clay. For DSC, it was observed that there was no change in melting temperature of the membranes of nanocomposites compared to membrane pure polyamide66. By TG, it was found that the decomposition of the membranes of polyamide66 with treated clay were higher compared with the untreated clay. (author)

  9. Clay slurry and engineered soils as containment technologies for remediation of contaminated sites

    International Nuclear Information System (INIS)

    Williams, J.R.; Dudka, S.; Miller, W.P.; Johnson, D.O.

    1997-01-01

    Clay Slurry and Engineered Soils are containment technologies for remediation of waste disposal sites where leaching, groundwater plumes and surface runoff of contaminants are serious ecological hazards to adjacent environments. This technology is a patent-pending process which involves the use of conditioned clay materials mixed with sand and water to form a readily pourable suspension, a clay slurry, which is either placed into a trench barrier system or allowed to de-water to create Engineered Soils. The Engineered Soil forms a layer impervious to water and air, therefore by inhibiting both water and oxygen from penetrating through the soil the material. This material can be installed in layers and as a vertical barrier to create a surface barrier containment system. The clay percentage in the clay slurry and Engineered Soils varies depending on site characteristics and desired performance standards. For example Engineered Soils with 1-2% of clay (dry wt.) had a hydraulic conductivity (K) of 10 -8 to 10 -1 cm/sec. Tests of tailing materials from a kyanite and pyrite mine showed that the clay slurry was effective not only in reducing the permeability of the treated tailings, but also in decreasing their acidity due to the inherent alkalinity of the clay. The untreated tailings had pH values in the range of 2.4 - 3.1; whereas, the effluent from clay and tailings mixtures had pH values in a slightly alkaline range (7.7-7.9). Pug-mills and high volume slurry pumps can be readily adapted for use in constructing and placing caps and creating Engineered Soils. Moreover, material on site or from a local sand supply can be used to create clay slurries and engineered soils. Clay materials used in cap construction are likewise readily available commercially. As a result, the clay slurry system is very cost effective compared to other capping systems, including the commonly used High Density Polyethylene (HDPE) liner systems

  10. Boron enrichment in martian clay.

    Directory of Open Access Journals (Sweden)

    James D Stephenson

    Full Text Available We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration.

  11. CLAY SOIL STABILISATION USING POWDERED GLASS

    Directory of Open Access Journals (Sweden)

    J. OLUFOWOBI

    2014-10-01

    Full Text Available This paper assesses the stabilizing effect of powdered glass on clay soil. Broken waste glass was collected and ground into powder form suitable for addition to the clay soil in varying proportions namely 1%, 2%, 5%, 10% and 15% along with 15% cement (base by weight of the soil sample throughout. Consequently, the moisture content, specific gravity, particle size distribution and Atterberg limits tests were carried out to classify the soil using the ASSHTO classification system. Based on the results, the soil sample obtained corresponded to Group A-6 soils identified as ‘fair to poor’ soil type in terms of use as drainage and subgrade material. This justified stabilisation of the soil. Thereafter, compaction, California bearing ratio (CBR and direct shear tests were carried out on the soil with and without the addition of the powdered glass. The results showed improvement in the maximum dry density values on addition of the powdered glass and with corresponding gradual increase up to 5% glass powder content after which it started to decrease at 10% and 15% powdered glass content. The highest CBR values of 14.90% and 112.91% were obtained at 5% glass powder content and 5mm penetration for both the unsoaked and soaked treated samples respectively. The maximum cohesion and angle of internal friction values of 17.0 and 15.0 respectively were obtained at 10% glass powder content.

  12. Obtention of chemically modified clays: organovermiculites

    International Nuclear Information System (INIS)

    Santana, Lisiane N.L.; Silva, Andrea L.; Barbosa, Estefane; Neves, Gelmires A.; Menezes, Romualdo Rodrigues

    2012-01-01

    The organovermiculite is obtained by incorporating the quaternary ammonium salt in the clay mineral vermiculite interlayer space. The objective of this work was to prepare organovermiculites for applications in organic contaminants adsorption. The variation of interlayer space was determined when the vermiculite was treated with an ionic salt (Praepagem WB) and a non-ionic salt (Amina Etoxilada TA50) in different concentrations. Before interacting with quaternary ammonium salt, the clay mineral was subjected to cationic change process with Na 2 CO 3 to substitute Mg 2+ by Na + . The results showed enlargement of interlayer space, reaching values up to 60.0 Å. The vermiculite pre-activated with Na 2 CO 3 during 5 days and modified with the Praepagem WB showed the best performance. Amina Etoxilada TA50 salt was not observed significant changes with increasing concentration. The affinity of organovermiculite for organic solvents was confirmed by Foster swelling test and the best results were observed with diesel and petrol as solvents. (author)

  13. Methylene blue adsorption in clay mineral dealt with organic cation

    International Nuclear Information System (INIS)

    Silva, T.L.; Lemos, V.P.

    2011-01-01

    The interaction among organic cations, as the methylene blue (AM) and benzyltrimethylammonium (BTMA), and clay minerals of the group of the smectite they result in the formation of applied materials in the adsorption of organic pollutant presents in waters, soils and you cultivate. In this work they were prepared the adsorbents (organic-clays) smectite - AM and smectite-BTMA. The precursory sample of smectite was collected in Rio Branco-Acre. We were also used an smectite sample collected in Sena Madureira (SM)-Acre already characterized in previous work and a sample of standard smectite Swy-2-Na-Montmorillonite (SWy-2) of Wymong - USA. The organic agents selected for this study they were: Blue of Methylene, denominated AM and Benzyltrimethylammonium, denominated BTMA. They were appraised the capacities adsorptive of the treated samples with BTMA being used AM as adsorbate. The results of these evaluations detected that ran total adsorption of AM (concentrations varying from 1 to 10 ppm) for the treated samples with BTMA. The organic cation, BTMA, interacting with the surfaces of the natural clay was more efficient in the adsorption of AM than the clay without the previous treatment with this salt. (author)

  14. Stools - pale or clay-colored

    Science.gov (United States)

    ... gov/ency/article/003129.htm Stools - pale or clay-colored To use the sharing features on this page, please enable JavaScript. Stools that are pale, clay, or putty-colored may be due to problems ...

  15. Phosphonium modified clay/polyimide nanocomposites

    International Nuclear Information System (INIS)

    Ceylan, Hatice; Çakmakçi, Emrah; Beyler-Çiǧil, Asli; Kahraman, Memet Vezir

    2014-01-01

    In this study, octyltriphenylphosphonium bromide [OTPP-Br] was prepared from the reaction of triphenylphosphine and 1 -bromooctane. The modification of clay was done by ion exchange reaction using OTPP-Br in water medium. Poly(amic acid) was prepared from the reaction of 3,3',4,4'-Benzophenonetetracarboxylic dianhydride (BTDA) and 4,4'-Oxydianiline (ODA). Polyimide(PI)/clay hybrids were prepared by blending of poly(amic acid) and organically modified clay as a type of layered clays. The morphology of the Polyimide/ phosphonium modified clay hybrids was characterized by scanning electron microscopy (SEM). Chemical structures of polyimide and Polyimide/ phosphonium modified clay hybrids were characterized by FTIR. SEM and FTIR results showed that the Polyimide/ phosphonium modified clay hybrids were successfully prepared. Thermal properties of the Polyimide/ phosphonium modified clay hybrids were characterized by thermogravimetric analysis (TGA)

  16. Geotechnical properties of Karwar marine clay

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat, S.T.; Nayak, B.U.; Naik, R.L.

    Karwar marine clay possesses high plasticity characteristics with natural water content higher than the liquid limit. Liquidity index was as high as 1.7. Predominant clay mineral was kaolinite. Undrained shear strength showed an increasing trend...

  17. Additive to clay drilling muds

    Energy Technology Data Exchange (ETDEWEB)

    Voytenko, V.S.; Nekrasova, V.B.; Nikitinskiy, E.L.; Ponomarev, V.N.

    1984-01-01

    The purpose of the invention is to improve the lubricating and strengthening properties of clay drilling muds. This goal is achieved because the lubricating and strengthening additive used is waste from the pulp and paper industry at the stage of reprocessing crude sulfate soap into phytosterol.

  18. Picasso Masks: Cubism in Clay

    Science.gov (United States)

    Daddino, Michelle

    2010-01-01

    This article describes an art project developed by the author which provides a way to further the children's understanding of Picasso's Cubism style in 3-D. Through this project, upper-elementary students learn a bit about the life and art of Picasso as they gain a firm understanding of the style of art known as Cubism, and apply clay techniques…

  19. ADSORPTION OF SURFACTANT ON CLAYS

    Science.gov (United States)

    Surfactants used to enhance remediation of soils by soil washing are often lost in the process. Neither the amount nor the cause of this loss is known. It is assumed that clays present in the soil are responsible for the loss of the surfactant. In this papere, adsorption prope...

  20. 21 CFR 186.1256 - Clay (kaolin).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Clay (kaolin). 186.1256 Section 186.1256 Food and... Substances Affirmed as GRAS § 186.1256 Clay (kaolin). (a) Clay (kaolin) Al2O3.2SiO2.nH2O, Cas Reg. No. 1332-58-7) consists of hydrated aluminum silicate. The commercial products of clay (kaolin) contain...

  1. generalized constitutive model for stabilized quick clay

    African Journals Online (AJOL)

    QUICK CLAY. PANCRAS MUGISHAGWE BUJULU AND GUSTAV GRIMSTAD. ABSTRACT. An experimentally-based two yield surface constitutive model for cemented quick clay has been ... Clay Model, the Koiter Rule and two Mapping Rules. .... models, where a mobilization formulation is used, this is independent of q.

  2. Clay Cuffman: A Cool, Calm, Relaxed Guy

    Science.gov (United States)

    Booth, Gina

    2010-01-01

    This article describes Clay Cuffman, a simple clay-sculpture project that requires two or three sessions, and works for students from the upper-elementary level through high school. It takes about 1.5 pounds of clay per student--about the size of a small grapefruit. The Cuffman project is a great way for upper-elementary through high-school…

  3. The systems containing clays and clay minerals from modified drug release: a review.

    Science.gov (United States)

    Rodrigues, Luís Alberto de Sousa; Figueiras, Ana; Veiga, Francisco; de Freitas, Rivelilson Mendes; Nunes, Lívio César Cunha; da Silva Filho, Edson Cavalcanti; da Silva Leite, Cleide Maria

    2013-03-01

    Clays are materials commonly used in the pharmaceutical industry, either as ingredients or as active ingredients. It was observed that when they are administered concurrently, they may interact with drugs reducing their absorption. Therefore, such interactions can be used to achieve technological and biopharmaceutical advantages, regarding the control of release. This review summarizes bibliographic (articles) and technological (patents) information on the use of systems containing clays and clay minerals in modified drug delivery. In this area, formulations such natural clay, commercial clay, synthetic clay, composites clay-polymers, nanocomposites clay-polymers, films and hidrogels composites clay-polymers are used to slow/extend or vectorize the release of drugs and consequently they increase their bioavailability. Finally, this review summarizes the fields of technology and biopharmaceutical applications, where clays are applied. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Technetium migration in natural clays

    International Nuclear Information System (INIS)

    Luebke, Maria

    2015-01-01

    The present work was performed within the joint research project ''Retention of repository relevant radionuclides in argillaceous rocks and saline systems'' (contract no.: 02E10981), funded by the Federal Ministry for Economic Affairs and Energy (BMWi). The aim was to obtain first insights into the interaction of the long-lived fission product technetium and natural clay with regard to a repository for high-level nuclear waste. For this purpose Opalinus Clay from Mont Terri (northern Switzerland) was used as a reference material. The nuclide technetium-99 will contribute to the radiotoxicity of spent nuclear fuel for more than thousand years due to its long half-live. In case of a leakage of the storage vessels, the geochemistry of technetium is determined by its oxidation state, at which only the oxidation states +IV and +VII are relevant. Because of the high solubility and low affinity to sorption on surfaces of minerals, Tc(VII) is considered to be very mobile and thus the most hazardous species. The focuses of this study therefore are diffusion experiments with this mobile species and investigations of the effect of ferrous iron on the mobility and speciation of technetium.rnThe interaction of technetium and Opalinus Clay was studied in sorption and diffusion experiments varying several parameters (pH value, addition of reducing agents, effect of oxygen, diffusion pathways). In the course of this study spatially resolved investigations of the speciation have been performed on Opalinus Clay thin sections and bore cores for the first time. In addition to the speciation, further information regarding elemental distributions and crystalline phases near technetium enrichments were obtained. Supplementary investigations of powder samples allowed determining the molecular structure of technetium on the clay surface.rnBoth the combination of sorption experiments with spectroscopic investigations and the diffusion experiment exhibit a reduction of Tc

  5. Mineral acquisition from clay by budongo forest chimpanzees

    NARCIS (Netherlands)

    Reynolds, Vernon; Lloyd, Andrew W.; English, Christopher J.; Lyons, Peter; Dodd, Howard; Hobaiter, Catherine; Newton-Fisher, Nicholas; Mullins, Caroline; Lamon, Noemie; Schel, Anne Marijke; Fallon, Brittany

    2015-01-01

    Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay

  6. Preparation and characterization of bentonite organo clay

    International Nuclear Information System (INIS)

    Bertagnolli, C.; Almeida Neto, A.F.; Silva, M.G.C.

    2009-01-01

    Bentonite clays organically modified have great potential use for environmental remediation, especially in the separation of organic compounds from the water. The aim of this work was the preparation of organophilic clays from 'Verde-Lodo' bentonite clay with the quaternary ammonium salts cetyl-pyridinium chloride and benzalkonium chloride. The materials obtained were characterized by XRD, thermogravimetric analyses, Helium picnometry, SEM and energy dispersive X-ray techniques. The results show consistently successful synthesis of the organoclay through the increase in the basal spacing, as well as salt elimination picks and presence of carbon and chlorine in the modified clays; they are inexistent elements in the natural clay. (author)

  7. Light clay straw bale solutions in the contemporary housing as an element of sustainable development. Selected issues

    Directory of Open Access Journals (Sweden)

    Drozd Wojciech

    2016-01-01

    Full Text Available The article presents issues related to the solutions with light clay and straw bale in the contemporary housing. Building using straw bale and light clay is simple, eco-friendly and accessible to all. It fits in with the idea of sustainable development, supporting local businesses and giving people the opportunity to integrate in the design and construction of the house. The article presents the thermal analysis for both walls made of straw bale and of light clay. The analysis showed a very good performance. All positive aspects allow treating straw and light clay as a viable alternative to the commonly used technologies for erecting buildings.

  8. Thermomechanical behaviour of boom clay

    International Nuclear Information System (INIS)

    Sultan, N.; Delage, P.; Cui, Y.J.

    2000-01-01

    Special attention has been recently paid on temperature effects on the behaviour of deep saturated clays, in relation with nuclear deep waste storage. However, few experimental data are presently available, and existing constitutive models need to be completed. This note is aimed at completing, both experimentally and theoretically, the understanding of the effects of the over-consolidation ration on the thermal volume changes of Boom clay (Belgium). The experimental data obtained here are in a good agreement with existing data. As a complement to existing data, they are used to develop a new elastoplastic model. The adoption of a second coupled plastic mechanism provides good simulations on a complex thermo-mechanical path. (authors)

  9. Stabilization Of Marine Clay Using Biomass Silica-Rubber Chips Mixture

    Science.gov (United States)

    Marto, Aminaton; Ridzuan Jahidin, Mohammed; Aziz, Norazirah Abdul; Kasim, Fauziah; Zurairahetty Mohd. Yunus, Nor

    2016-11-01

    Marine clay is found widely along the coastal area and had caused expensive solutions in the construction of coastal highways. Hence, soil stabilization was suggested by some consultant to increase the strength of this soil in order to meet the highway construction requirement and also to achieve the specification for the development. Biomass Silica (BS), particularly the SH85 as a non-traditional stabilisation method, has been gaining more interest from the engineers recently. Rubber chips (RC), derived from waste rubber tyres, are considered ‘green’ element and had been used previously in some geotechnical engineering works. This paper presents the effect of using BS and RC as a mixture (BS-RC mixture), to increase the strength of marine clay for highway construction. Samples of marine clay, obtained from the West Coast Expressway project at Teluk Intan, Perak, were oven dried and grind to fine-grained sized. The marine clay was mixed with 9 % by weight proportion of BS- RC; that were 8%-l% and 7%-2%, respectively. For comparison purposes the result of BS-RC was compared to the result of stabilization by using 9% BS only. Laboratory tests were then carried out to determine the Atterberg limits and compaction characteristics of the untreated and treated marine clay. The Unconfined Compressive Strength (UCS) of the untreated and treated marine clays, compacted at the optimum moisture content was later obtained. The treated marine clay was tested at 0, 3 and 7 days curing periods. The results show that the Plasticity Index of BS-RC treated marine clay was lower than the untreated marine clay. From the UCS test results, it is shown that BS-RC mixtures had significantly improved the strength of marine clay. With the same percentage of 9% BS-RC, the increased of BS from 7% to 8% increased the UCS further to about six times more than untreated marine clay soils in 7 days curing period. The strength gained by using BS-RC at 8%-1% is slightly below the strength by

  10. The absorption of Mn-54 onto some kinds of clay in aqueous solution

    International Nuclear Information System (INIS)

    Chu Minh Khoa; Le Van So

    2000-01-01

    The absorption of radioactive Mn-54 from aqueous solutions by natural treated clay of Dilinh region has been investigated. The effect of many factors such as time, pH, carrier concentration... were studied. It was found that the uptake is maximum in neutral or slightly alkaline solutions. The experimental results show that natural clay is suited for the moval of radioactive Mn-54. These types of clay may be considered superior to synthetic exchangers for the removal of Mn-54 if the availability and price of the former are taken into account. (author)

  11. Hyperspectral analysis of clay minerals

    Science.gov (United States)

    Janaki Rama Suresh, G.; Sreenivas, K.; Sivasamy, R.

    2014-11-01

    A study was carried out by collecting soil samples from parts of Gwalior and Shivpuri district, Madhya Pradesh in order to assess the dominant clay mineral of these soils using hyperspectral data, as 0.4 to 2.5 μm spectral range provides abundant and unique information about many important earth-surface minerals. Understanding the spectral response along with the soil chemical properties can provide important clues for retrieval of mineralogical soil properties. The soil samples were collected based on stratified random sampling approach and dominant clay minerals were identified through XRD analysis. The absorption feature parameters like depth, width, area and asymmetry of the absorption peaks were derived from spectral profile of soil samples through DISPEC tool. The derived absorption feature parameters were used as inputs for modelling the dominant soil clay mineral present in the unknown samples using Random forest approach which resulted in kappa accuracy of 0.795. Besides, an attempt was made to classify the Hyperion data using Spectral Angle Mapper (SAM) algorithm with an overall accuracy of 68.43 %. Results showed that kaolinite was the dominant mineral present in the soils followed by montmorillonite in the study area.

  12. Geochemical effects of electro-osmosis in clays

    KAUST Repository

    Loch, J. P. Gustav

    2010-02-13

    Geochemical effects of electro-osmosis in bentonite clay are studied in the laboratory, where a 6 mm thick bentonite layer is subjected to direct current. Acidification and alkalization near anode and cathode are expected, possibly causing mineral deterioration, ion mobilization and precipitation of new solids. Afterwards the clay is analysed by XRF and anolyte and catholyte are analysed by ICP-MS. In addition, as a preliminary experiment treated bentonite is analysed by high resolution μ-XRF. Electro-osmotic flow is observed. Due to its carbonate content the bentonite is pH-buffering. Alkalization in the catholyte is substantial. Ca, Na and Sr are significantly removed from the clay and accumulate in the catholyte. Recovery in the catholyte accounts for a small fraction of the element-loss from the clay. The rest will have precipitated in undetected solid phases. μ-XRF indicates the loss of Ca-content throughout the bentonite layer. © The Author(s) 2010.

  13. Influence of processing conditions in PEA/organophilic clay nanocomposites

    International Nuclear Information System (INIS)

    Araujo, E.M.; Kojuch, L.R.; Barbosa, R.; Nobrega, K.C.; Melo, T.J.A. de

    2008-01-01

    Polymer/clay nanocomposites have attracted great interest from the industry as well as from the researches due to the need to obtain materials with desired properties. Nanocomposites with silicates layer represent an alternative for the conventional composites because they use a small amount of nanofiller. In this work, polyethylene/polyethylene grafted anhydride maleic (PE-g-MA)/montmorillonite clay (MMT) nanocomposites were prepared by melt intercalation in a Torque Rheometer. It was used an untreated clay (MMT) and a treated clay with the quaternary ammonium salt (OMMT). The influence of the processing conditions was evaluated, that is: 60 and 120rpm, 7 and 14 min, 190 and 220°C. The obtained systems were characterized by X-ray diffraction (XRD) and rheological behavior. The results from XRD and rheological behavior indicated that the system composed of polyethylene/PE-g-MA/OMMT presented intercalated nanocomposite structure, with larger basal distance and high viscosity, in the conditions of 120rpm and 7min, independent of temperature. (author)

  14. The Ypresian clays as alternative host rock for radioactive waste disposal in Belgium. A transferability study

    International Nuclear Information System (INIS)

    Van Baelen, Herve; Wouters, Laurent; Brassinnes, Stephane; Van Geet, Maarten; Vandenberghe, Noel

    2012-01-01

    adaptations to the current design might be necessary due to the dissimilarities with Boom Clay. From our analysis of the available data, it is remarkable that for a number of parameters, the Ypresian clays appear to be less homogeneous than Boom Clay. Therefore special research efforts will be needed to get a hold on this spatial variability. Additionally, there are indications that the precision and accuracy of measurements are low for some of the parameters, which might explain a part of the heterogeneity observed. This seems to be the case for the pore-water chemistry, which will, given the impact it might have on corrosion, the durability of cementitious phases and the retention mechanisms within the host rock, be one of the major issues in future research and one of the reasons to adapt the design. Another important issue to be studied specifically for the Ypresian clays will be its mechanical behaviour at the conditions prevailing at excavation, exploitation and after closure of the disposal system. This might again, in the light of feasibility as well as safety issues, have an impact on the design. Apart from these major research questions arising from dissimilarities between both potential host rocks, a number of research questions are host-rock independent or can, at this stage of research, be treated as similar or followed-up by small-scale studies, because of comparable host rock properties. On the basis of the current knowledge it is concluded that the Ypresian clays remain a valuable alternative to Boom Clay as potential host rock for the geological disposal of high-level and/or long-lived radioactive waste

  15. From clay bricks to deep underground storage

    International Nuclear Information System (INIS)

    2012-05-01

    This booklet issued by the Swiss National Cooperative for the Disposal of Radioactive Waste NAGRA takes a look at the use of clay strata for the storage of radioactive wastes in deep-lying repositories. First of all, a geological foray is made concerning the history of the use of clay and its multifarious uses. The characteristics of clay and its composition are examined and its formation in the geological past is explained. In particular Opalinus clay is looked at and the structures to be found are discussed. The clay's various properties and industrial uses are examined and its sealing properties are examined. Also, Bentonite clay is mentioned and work done by Nagra and co-researchers is noted

  16. Organophilization and characterization of commercial bentonite clays

    International Nuclear Information System (INIS)

    Cunha, B.B. da; Lima, J.C.C.; Alves, A.M.; Araujo, E.M.; Melo, T.J.A. de

    2012-01-01

    Bentonite clay is a plastic changes resulting from volcanic ash, consisting mostly of montmorillonite. The state of Paraiba is a major source of bentonite clay from Brazil, where the main oil fields are located in Boa Vista and represents the largest national production of raw and beneficiated bentonite. Aimed at the commercial value of this type of clay and its high applicability in the polls, this article aims to make a comparison between two kinds of clay, a national (Brasgel) and other imported (Cloisite) from organophilization of two commercial bentonite, ionic surfactant with Praepagem WB, and characterize them by XRD, FTIR and TG / DTG. We observe that despite getting inferior properties, the clay presents national values very similar to those presented by imported clay. (author)

  17. Optimization of organo clay production for applications in based oil drilling fluid; Otimizacao do processo de organofilizacao para aplicacoes em fluidos de perfuracao base oleo

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Heber S; Martins, Alice B; Costa, Danubia L. da; Ferreira, Heber C; Neves, Gelmires de A; Melo, Tomas J.A. de [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Teixeira Neto, Erico [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

    2008-07-01

    The organophilic clays are widely used as an agent dispersed in the composition of oil based drilling fluids. The organophilic clays are gotten from bentonite clays treated, in watery way, with ionic surfactants, that are adsorbed in the surface of interlayer of the clays, re-covered them with a organic layer. A fundamental stage of production of the organophilic clays is the dispersion of bentonite clays, in way that variables like: speed of agitation, temperature and time of cure, influences directly in plastic and apparent viscosities of these dispersions, together with other variables of organophilization process, like, temperature and time of cure of organophilization, has direct influence in efficiency of the organophilization process. This work considers a study of these variable, using bentonite clays: Brasgel PA{sup R} and Cloisite Na{sup +R}, treated with the ionic surfactant Praepagem WB{sup R}. The organophilic clays gotten had been characterized by rays X diffraction, Foster's swelling, and the results were compared with the commercial organophilic clay VG-69{sup R}, industrially treated with ionic surfactant. Viscosities plastic and apparent of the dispersions had been measured in the midst of organic dispersant diesel oil used to obtain the oil based drilling fluids. Preliminary results of Foster's swelling and preparation of fluids show that the clays have affinity with the means liquid organic dispersants, and the fluids meet specifications of PETROBRAS (N-22581-1997 and N-2259 to 1997) for use in the of diesel oil based drilling fluids. (author)

  18. Mars, clays and the origins of life

    Science.gov (United States)

    Hartman, Hyman

    1989-01-01

    To detect life in the Martian soil, tests were designed to look for respiration and photosynthesis. Both tests (labeled release, LR, and pyrolytic release, PR) for life in the Martian soils were positive. However, when the measurement for organic molecules in the soil of Mars was made, none were found. The interpretation given is that the inorganic constituents of the soil of Mars were responsible for these observations. The inorganic analysis of the soil was best fitted by a mixture of minerals: 60 to 80 percent clay, iron oxide, quartz, and soluble salts such as halite (NaCl). The minerals most successful in simulating the PR and LR experiments are iron-rich clays. There is a theory that considers clays as the first organisms capable of replication, mutation, and catalysis, and hence of evolving. Clays are formed when liquid water causes the weathering of rocks. The distribution of ions such as aluminum, magnesium, and iron play the role of bases in the DNA. The information was stored in the distribution of ions in the octahedral and tetrahedral molecules, but that they could, like RNA and DNA, replicate. When the clays replicated, each sheet of clay would be a template for a new sheet. The ion substitutions in one clay sheet would give rise to a complementary or similar pattern on the clay synthesized on its surface. It was theorized that it was on the surface of replicating iron-rich clays that carbon dioxide would be fixed in the light into organic acids such as formic or oxalic acid. If Mars had liquid water during a warm period in its past, clay formation would have been abundant. These clays would have replicated and evolved until the liquid water was removed due to cooling of Mars. It is entirely possible that the Viking mission detected life on Mars, but it was clay life that awaits the return of water to continue its evolution into life based on organic molecules.

  19. Fracture behavior of polypropylene/clay nanocomposites.

    Science.gov (United States)

    Chen, Ling; Wang, Ke; Kotaki, Masaya; Hu, Charmaine; He, Chaobin

    2006-12-01

    Polypropylene (PP)/clay nanocomposites have been prepared via a reactive compounding approach with an epoxy based masterbatch. Compared with PP and common PP/organoclay nanocomposites, the PP/clay nanocomposites based on epoxy/clay masterbatch have higher impact strength. The phenomenon can be attributed to the epoxy phase dispersed uniformly in the PP matrix, which may act as impact energy absorber and helps to form a large damage zone, thus a higher impact strength value is achieved.

  20. Multifaceted role of clay minerals in pharmaceuticals

    OpenAIRE

    Khurana, Inderpreet Singh; Kaur, Satvinder; Kaur, Harpreet; Khurana, Rajneet Kaur

    2015-01-01

    The desirable physical and physiochemical properties of clay minerals have led them to play a substantial role in pharmaceutical formulations. Clay minerals like kaolin, smectite and palygorskite-sepiolite are among the world's most valuable industrial minerals and of considerable importance. The elemental features of clay minerals which caused them to be used in pharmaceutical formulations are high specific area, sorption capacity, favorable rheological properties, chemical inertness, swelli...

  1. Selective Clay Placement Within a Silicate-Clay Epoxy Blend Nanocomposite

    Science.gov (United States)

    Miller, Sandi G (Inventor)

    2013-01-01

    A clay-epoxy nanocomposite may be prepared by dispersing a layered clay in an alkoxy epoxy, such as a polypropylene oxide based epoxide before combining the mixture with an aromatic epoxy to improve the nanocomposite's thermal and mechanical properties.

  2. Iodide uptake by negatively charged clay interlayers?

    Science.gov (United States)

    Miller, Andrew; Kruichak, Jessica; Mills, Melissa; Wang, Yifeng

    2015-09-01

    Understanding iodide interactions with clay minerals is critical to quantifying risk associated with nuclear waste disposal. Current thought assumes that iodide does not interact directly with clay minerals due to electrical repulsion between the iodide and the negatively charged clay layers. However, a growing body of work indicates a weak interaction between iodide and clays. The goal of this contribution is to report a conceptual model for iodide interaction with clays by considering clay mineral structures and emergent behaviors of chemical species in confined spaces. To approach the problem, a suite of clay minerals was used with varying degrees of isomorphic substitution, chemical composition, and mineral structure. Iodide uptake experiments were completed with each of these minerals in a range of swamping electrolyte identities (NaCl, NaBr, KCl) and concentrations. Iodide uptake behaviors form distinct trends with cation exchange capacity and mineral structure. These trends change substantially with electrolyte composition and concentration, but do not appear to be affected by solution pH. The experimental results suggest that iodide may directly interact with clays by forming ion-pairs (e.g., NaI(aq)) which may concentrate within the interlayer space as well as the thin areas surrounding the clay particle where water behavior is more structured relative to bulk water. Ion pairing and iodide concentration in these zones is probably driven by the reduced dielectric constant of water in confined space and by the relatively high polarizability of the iodide species. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Organic waste treatment with organically modified clays

    International Nuclear Information System (INIS)

    Evans, J.C.; Pancoski, S.E.; Alther, G.

    1989-01-01

    The use of organically modified clays in hazardous waste management applications offers a significant new and untapped potential. These clays may be used in the stabilization of organic wastes and organically contaminated soils, for waste water treatment, for oil spill control, for liner systems beneath fuel oil storage tanks, and as a component within liner systems of hazardous waste storage treatment and disposal facilities. Organically modified clays (organophilic clays) may be employed in each of these systems to adsorb organic waste constituents, enhancing the performance of the applications

  4. Natural analogues and evidence of long-term isolation capacity of clays occurring in Italy

    International Nuclear Information System (INIS)

    Benvegnu, F.; Brondi, A.; Polizzano, C.

    1988-01-01

    This work concerns the results of the studies conducted at many sites in Italy aimed at collecting information on natural evidences of the isolation capacity of clay. Field observations allow to get the opportunity to know directly or infer the evolutive geological processes which are of concern for the waste disposal problems. As a major advantage such observations concern natural phenomena acting at the same, or at a greater, time-space scale involved in the geological disposal of wastes. The explored situations regard the secondary permeability of clay, detected by means of natural tracers (Hg, He, hydrothermal and geothermal fluids, ....) at the ground surface or directly studied in deep civilian tunnels. Another treated topic is the meaning of the oxido-reduction front as a control factor of the physico-chemical environment of clay as well as of the radionuclides migration. The mechanical and thermal effects which accompany the intrusion of a subvolcanic body within clay represent an extreme worst case for a comparison of the effects on clay due to heat developed by radionuclide decay. Finally the case of a fossil forest maintained almost inaltered by the clay cover for over 1,500,000 years is described. All the results of the geological researches point univocally to an almost total and long lasting isolation capacity of clay formations

  5. Concrete-Opalinus clay interaction

    International Nuclear Information System (INIS)

    Jenni, A.; Maeder, U.; Lerouge, C.; Gaboreau, S.; Schwyn, B.

    2012-01-01

    Document available in extended abstract form only. Designs for deep geologic disposal of radioactive waste foresee cementitious materials as structural elements, backfill or waste matrix. Therefore, studies of interactions between cement and all other materials involved are important. Interactions are mostly driven by chemical gradients in pore water and might lead to mineralogical alterations in the barrier system, which in turn influence properties like swelling pressure, permeability, or specific retention in case of clay materials. Existing laboratory and in-situ studies using clay-stone revealed significant alteration in both cement and clay-stone. Phase dissolution, precipitation, and carbonation, were found to cause an overall porosity increase in the cement with a possible decrease close to the interface, and clogging in the clay-stone [2]. Most of the work was done on cement pastes rather than concretes to avoid analytical complications caused by aggregates, and the scale of investigation was chosen in the range of centimetres rather than micrometers. The Cement-Clay Interaction (CI) experiment at the Mont Terri Underground Laboratory (St. Ursanne, Switzerland) aims at replicating some of the processes at interfaces to be expected.For this purpose, two vertical cylindrical boreholes (384 mm diameter, up to 10 m length) in Opalinus Clay (OPA) were filled with layers of three different concretes and bentonite. The concrete formulations are based on common aggregate content and grain size distributions, combined with three different cements: Portland cement (OPC), ESDRED cement especially designed for repository applications (40% of cement substituted with silica fume), and low alkali cement (LAC, containing slag and nano-silica).In this study, we present a characterisation of the three concrete-OPA interfaces after two years of alteration and deduce possible mechanisms. Backscattered electron (BE) imaging and energy dispersive spectrum (EDX) element mapping

  6. Iodide uptake by negatively charged clay interlayers?

    International Nuclear Information System (INIS)

    Miller, Andrew; Kruichak, Jessica; Mills, Melissa; Wang, Yifeng

    2015-01-01

    Understanding iodide interactions with clay minerals is critical to quantifying risk associated with nuclear waste disposal. Current thought assumes that iodide does not interact directly with clay minerals due to electrical repulsion between the iodide and the negatively charged clay layers. However, a growing body of work indicates a weak interaction between iodide and clays. The goal of this contribution is to report a conceptual model for iodide interaction with clays by considering clay mineral structures and emergent behaviors of chemical species in confined spaces. To approach the problem, a suite of clay minerals was used with varying degrees of isomorphic substitution, chemical composition, and mineral structure. Iodide uptake experiments were completed with each of these minerals in a range of swamping electrolyte identities (NaCl, NaBr, KCl) and concentrations. Iodide uptake behaviors form distinct trends with cation exchange capacity and mineral structure. These trends change substantially with electrolyte composition and concentration, but do not appear to be affected by solution pH. The experimental results suggest that iodide may directly interact with clays by forming ion-pairs (e.g., NaI (aq) ) which may concentrate within the interlayer space as well as the thin areas surrounding the clay particle where water behavior is more structured relative to bulk water. Ion pairing and iodide concentration in these zones is probably driven by the reduced dielectric constant of water in confined space and by the relatively high polarizability of the iodide species. - Highlights: • Iodide sorption experiments were completed with a diverse array of clay minerals. • Iodide uptake trended with CEC and swamping electrolyte identity and concentration. • Results can be explained by considering the formation of ion pairs in clay interlayers

  7. Modeling of Cation Binding in Hydrated 2:1 Clay Minerals - Final Report

    International Nuclear Information System (INIS)

    Smith, David E.

    2000-01-01

    Hydrated 2:1 clay minerals are high surface area, layered silicates that play a unique role in determining the fate of radionuclides in the environment. This project consisted of developing and implementing computer simulation methods for molecular characterization of the swelling and ion exchange properties of Hydrated 2:1 clay minerals, and the subsequent analysis and theoretical modeling with a view toward improving contaminant transport modeling as well as soil remediation and radionuclide containment strategies. Project results included the (a) development of simulation methods to treat clays under environmentally relevant conditions of variable water vapor pressure; (b) calculation of clay swelling thermodynamics as a function of interlayer ion size and charge (calculated quantities include immersion energies, free energies, and entropies of swelling); and (c) calculation of ion exchange free energies, including contributions from changing interlayer water contents and layer spacing

  8. Six-phase soil heating accelerates VOC extraction from clay soil

    International Nuclear Information System (INIS)

    Gauglitz, P.A.; Roberts, J.S.; Bergsman, T.M.; Caley, S.M.; Heath, W.O.; Miller, M.C.; Moss, R.W.; Schalla, R.; Jarosch, T.R.; Eddy-Dilek, C.A.

    1994-08-01

    Six-Phase Soil Heating (SPSH) was demonstrated as a viable technology for heating low permeability soils containing volatile organic contaminants. Testing was performed as part of the Volatile Organic Compounds in Non-Arid Soils Integrated Demonstration (VOC Non-Arid ID) at the Savannah River Site. The soil at the integrated demonstration site is contaminated with perchloroethylene (PCE) and trichloroethylene (TCE); the highest soil contamination occurs in clay-rich zones that are ineffectively treated by conventional soil vapor extraction due to the very low permeability of the clay. The SPSH demonstration sought to heat the clay zone and enhance the performance of conventional soil vapor extraction. Thermocouples at thirty locations quantified the areal and vertical heating within the treated zone. Soil samples were collected before and after heating to quantify the efficacy of heat-enhanced vapor extraction of PCE and TCE from the clay soil. Samples were taken (essentially every foot) from six wells prior to heating and adjacent to these wells after heating. Results show that contaminant removal from the clay zone was 99.7% (median) within the electrode array. Outside the array where the soil was heated, but to only 50 degrees C, the removal efficiency was 93%, showing that heating accelerated the removal of VOCs from the clay soil. The accelerated remediation resulted from effective heating of the contaminated clay zone by SPSH. The temperature of the clay zone increased to 100 degrees C after 8 days of heating and was maintained near 100 degrees C for 17 days. Electrical heating removed 19,000 gal of water from the soil as steam, with peak removal rate of 1,500 gpd of condensed steam

  9. Sectioning Clay Models Makes Anatomy & Development Tangible

    Science.gov (United States)

    Howell, Carina Endres; Howell, James Endres

    2010-01-01

    Clay models have proved to be useful teaching aids for many topics in biology that depend on three-dimensional reasoning. Students studying embryonic development struggle to mentally reconstruct the three-dimensional structure of embryos and larvae by observing prepared slides of cross-sectional slices. Students who build clay models of embryos…

  10. Clay as Thermoluminescence Dosemeter in diagnostic Radiology ...

    African Journals Online (AJOL)

    This paper reports the investigation of the basic thermoluminescence properties of clay at x-rays in the diagnostic radiology range, including dose monitoring in abdominal radiography. Clay sourced from Calabar, Nigeria, was tested for thermoluminescence response after irradiation at diagnostic radiology doses, including ...

  11. Climatic control on clay mineral formation

    Indian Academy of Sciences (India)

    Many physico-chemical variables like rock-type,climate,topography and exposure age affect weathering environments.In the present study,an attempt is made to understand how the nature of clay minerals formed due to weathering differs in tropical regions receiving high and low rainfall. Clay mineralogy of weathering pro ...

  12. clay nanocomposite by solution intercalation technique

    Indian Academy of Sciences (India)

    Polymer–clay nanocomposites of commercial polystyrene (PS) and clay laponite were prepared via solution intercalation technique. Laponite was modified suitably with the well known cationic surfactant cetyltrimethyl ammonium bromide by ion-exchange reaction to render laponite miscible with hydrophobic PS.

  13. The many ways of making anionic clays

    Indian Academy of Sciences (India)

    Together with hydrotalcite-like layered double hydroxides, bivalent and trivalent metal hydroxides and their hydroxy salts are actually anionic clays consisting of positively charged hydroxide layers with anions intercalated in the interlayer region. The anionic clays exhibit anion sorption, anion diffusion and exchange ...

  14. Investigations of salt mortar containing saliferous clay

    International Nuclear Information System (INIS)

    Walter, F.

    1992-01-01

    Saliferous clay mortar might be considered for combining individual salt bricks into a dense and tight long-term seal. A specific laboratory program was started to test mortars consisting of halite powder and grey saliferous clay of the Stassfurt from the Bleicherode salt mine. Clay fractions between 0 and 45% were used. The interest focused upon obtaining good workabilities of the mixtures as well as upon the permeability and compression strength of the dried mortar samples. Test results: 1) Without loss of quality the mortar can be mixed using fresh water. Apprx. 18 to 20 weight-% of the solids must be added as mixing water. 2) The porosity and the permeability of the mortar samples increases distinctly when equally coarse-grained salt power is used for mixing. 3) The mean grain size and the grain size distribution of the saliferous clay and the salt powder should be very similar to form a useful mortar. 4) The permeability of the mortar samples decreases with increasing clay fraction from 2 10 -12 m 2 to 2 10 -14 m 2 . The investigated samples, however, were large and dried at 100degC. 5) The uniaxial compressive strength of the clay mortar equals, at an average, only 4 MPa and decreases clearly with increasing clay fraction. Moist mortar samples did not show any measurable compressive strength. 6) Moistened saliferous clay mortar may show little temporary swelling. (orig./HP)

  15. Hygrothermal behavior for a clay brick wall

    Science.gov (United States)

    Allam, R.; Issaadi, N.; Belarbi, R.; El-Meligy, M.; Altahrany, A.

    2018-06-01

    In Egypt, the clay brick is the common building materials which are used. By studying clay brick walls behavior for the heat and moisture transfer, the efficient use of the clay brick can be reached. So, this research studies the hygrothermal transfer in this material by measuring the hygrothermal properties and performing experimental tests for a constructed clay brick wall. We present the model for the hygrothermal transfer in the clay brick which takes the temperature and the vapor pressure as driving potentials. In addition, this research compares the presented model with previous models. By constructing the clay brick wall between two climates chambers with different boundary conditions, we can validate the numerical model and analyze the hygrothermal transfer in the wall. The temperature and relative humidity profiles within the material are measured experimentally and determined numerically. The numerical and experimental results have a good convergence with 3.5% difference. The surface boundary conditions, the ground effect, the infiltration from the closed chambers and the material heterogeneity affects the results. Thermal transfer of the clay brick walls reaches the steady state very rapidly than the moisture transfer. That means the effect of using only the external brick wall in the building in hot climate without increase the thermal resistance for the wall, will add more energy losses in the clay brick walls buildings. Also, the behavior of the wall at the heat and mass transfer calls the three-dimensional analysis for the whole building to reach the real behavior.

  16. Hygrothermal behavior for a clay brick wall

    Science.gov (United States)

    Allam, R.; Issaadi, N.; Belarbi, R.; El-Meligy, M.; Altahrany, A.

    2018-01-01

    In Egypt, the clay brick is the common building materials which are used. By studying clay brick walls behavior for the heat and moisture transfer, the efficient use of the clay brick can be reached. So, this research studies the hygrothermal transfer in this material by measuring the hygrothermal properties and performing experimental tests for a constructed clay brick wall. We present the model for the hygrothermal transfer in the clay brick which takes the temperature and the vapor pressure as driving potentials. In addition, this research compares the presented model with previous models. By constructing the clay brick wall between two climates chambers with different boundary conditions, we can validate the numerical model and analyze the hygrothermal transfer in the wall. The temperature and relative humidity profiles within the material are measured experimentally and determined numerically. The numerical and experimental results have a good convergence with 3.5% difference. The surface boundary conditions, the ground effect, the infiltration from the closed chambers and the material heterogeneity affects the results. Thermal transfer of the clay brick walls reaches the steady state very rapidly than the moisture transfer. That means the effect of using only the external brick wall in the building in hot climate without increase the thermal resistance for the wall, will add more energy losses in the clay brick walls buildings. Also, the behavior of the wall at the heat and mass transfer calls the three-dimensional analysis for the whole building to reach the real behavior.

  17. Geomechanics of clays for radioactive waste disposal

    International Nuclear Information System (INIS)

    Come, B.

    1989-01-01

    Clay formations have been studied for many years in the European Community as potential disposal media for radioactive waste. This document brings together results of on-going research about the geomechanical behaviour of natural clay bodies, at normal and elevated temperatures. The work is carried out within the third Community R and D programme on Management and storage of radioactive waste

  18. Quick clay and landslides of clayey soils

    NARCIS (Netherlands)

    Khaldoun, A.; Moller, P.; Fall, A.; Wegdam, G.; de Leeuw, B.; Méheust, Y.; Fossum, J.O.; Bonn, D.

    2009-01-01

    We study the rheology of quick clay, an unstable soil responsible for many landslides. We show that above a critical stress the material starts flowing abruptly with a very large viscosity decrease caused by the flow. This leads to avalanche behavior that accounts for the instability of quick clay

  19. Synthesis of templated carbons starting from clay and clay-derived zeolites for hydrogen storage applications

    CSIR Research Space (South Africa)

    Musyoka, Nicholas M

    2014-10-01

    Full Text Available 57 58 59 60 For Peer Review 1 Synthesis of templated carbons starting from clay and clay-derived zeolites for hydrogen storage applications N. M. Musyoka1*, J. Ren1, H. W. Langmi1, D. E. C. Rogers1, B. C. North1, M. Mathe1 and D. Bessarabov2... clear (filtered) extract of cloisite clay, SNC for zeolite from unfiltered cloisite clay extract and SBC for zeolite from unfiltered South African bentonite clay extract. Furfuryl alcohol (Sigma Aldrich, C5H6O2, 98%) and Ethylene gas were used...

  20. 1st International Conference on Calcined Clays for Sustainable Concrete

    CERN Document Server

    Favier, Aurélie

    2015-01-01

    This volume focuses on research and practical issues linked to Calcined Clays for Sustainable Concrete. The main subjects are geology of clays, hydration and performance of blended systems with calcined clays, alkali activated binders, economic and environmental impacts of the use of calcined clays in cement based materials. Topics addressed in this book include the influence of processing on reactivity of calcined clays, influence of clay mineralogy on reactivity, geology of clay deposits, Portland-calcined clay systems, hydration, durability, performance, Portland-calcined clay-limestone systems, hydration, durability, performance, calcined clay-alkali systems, life cycle analysis, economics and environmental impact of use of calcined clays in cement and concrete, and field applications. This book compiles the different contributions of the 1st International Conference on Calcined Clays for Sustainable Concrete, which took place in Lausanne, Switzerland, June, 23-25, 2015.The papers present the latest  res...

  1. Single clay sheets inside electrospun polymer nanofibers

    Science.gov (United States)

    Sun, Zhaohui

    2005-03-01

    Nanofibers were prepared from polymer solution with clay sheets by electrospinning. Plasma etching, as a well controlled process, was used to supply electrically excited gas molecules from a glow discharge. To reveal the structure and arrangement of clay layers in the polymer matrix, plasma etching was used to remove the polymer by controlled gasification to expose the clay sheets due to the difference in reactivity. The shape, flexibility, and orientation of clay sheets were studied by transmission and scanning electron microscopy. Additional quantitative information on size distribution and degree of exfoliation of clay sheets were obtained by analyzing electron micrograph of sample after plasma etching. Samples in various forms including fiber, film and bulk, were thinned by plasma etching. Morphology and dispersion of inorganic fillers were studied by electron microscopy.

  2. Some Tests on Heather Field Moraine Clay

    DEFF Research Database (Denmark)

    Jørgensen, Mogens B.; Jacobsen, Moust

    This report deals with oedometer tests on three samples of moraine clay from the Heather Field in the English part of the North Sea. The tests have been carried out in the very unelastic apparatus used in Denmark and with special test procedures differing from the ones used elsewhere. In Denmark...... Moraine Clay covers a large part of the surface, and it has therefore been investigated extensively in the field and in the laboratories during the last 25 years. It is to day - from a geotechnical point of view - the best known clay in Denmark. It could therefore be of some interest to compare...... the English North Sea moraine clays with the corresponding Danish Moraine Clays. The Danish test procedures are explained in details and some comments are given in the hope that they may not be banalities all of them....

  3. Active containment systems incorporating modified pillared clays

    International Nuclear Information System (INIS)

    Lundie, P.; McLeod, N.

    1997-01-01

    The application of treatment technologies in active containment systems provides a more advanced and effective method for the remediation of contaminated sites. These treatment technologies can be applied in permeable reactive walls and/or funnel and gate systems. The application of modified pillared clays in active containment systems provides a mechanism for producing permeable reactive walls with versatile properties. These pillared clays are suitably modified to incorporate reactive intercalatants capable of reacting with both a broad range of organic pollutants of varying molecular size, polarity and reactivity. Heavy metals can be removed from contaminated water by conventional ion-exchange and other reactive processes within the clay structure. Complex contamination problems can be addressed by the application of more than one modified clay on a site specific basis. This paper briefly describes the active containment system and the structure/chemistry of the modified pillared clay technology, illustrating potential applications of the in-situ treatment process for contaminated site remediation

  4. Clay Dispersibility and Soil Friability-Testing the Soil Clay-to-Carbon Saturation Concept

    DEFF Research Database (Denmark)

    Schjønning, Per; de Jonge, Lis Wollesen; Munkholm, Lars Juhl

    2012-01-01

    Soil organic carbon (OC) influences clay dispersibility, which affects soil tilth conditions and the risk of vertical migration of clay colloids. No universal lower threshold of OC has been identified for satisfactory stabilization of soil structure. We tested the concept of clay saturation with OC...... as a predictor of clay dispersibility and soil friability. Soil was sampled 3 yr in a field varying in clay content (∼100 to ∼220 g kg−1 soil) and grown with different crop rotations. Clay dispersibility was measured after end-over-end shaking of field-moist soil and 1- to 2-mm sized aggregates either air......-dried or rewetted to −100 hPa matric potential. Tensile strength of 1- to 2-, 2- to 4-, 4- to 8-, and 8- to 16-mm air-dried aggregates was calculated from their compressive strength, and soil friability estimated from the strength–volume relation. Crop rotation characteristics gave only minor effects on clay...

  5. Use of organophilic clays in purification of oily wastewater; Uso de argilas organofilicas na purificacao de efluentes oleosos

    Energy Technology Data Exchange (ETDEWEB)

    Silva, A.A. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Engenharia de Processos], email: adriana_anp@yahoo.com.br; Pereira, K.R de O.; Wiebeck, H.; Valenzuela-Diaz, F.R. [Universidade de Sao Paulo (EPUSP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Metalurgica e de Materiais; Rodrigues, M. G.F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). CCT. Dept. de Engenharia Quimica

    2006-07-01

    Water mixed with oil is produced in great volume in industrial processes and in petroleum refineries. This mixture must be treated to return to environment or can be reused in the same process. The refine of this water is expensive and presents a difficult execution. The process of separation of oil in water used organophilic clays can be a new option. In this work, the process of preparation of organophilic clays using smectitic clay polycationic and a industrial sodium bentonite both from Paraiba State, Brazil is described. The samples were characterized by two techniques: X-ray Diffraction and Thermal Analysis. After preparation of the organophilic clays it was determined theirs swelling in organic solvents and oil adsorption capacity. The organophilic clays presented higher capacity of oil adsorption when compared to activated carbon. (author)

  6. Large scale structures in liquid crystal/clay colloids

    Science.gov (United States)

    van Duijneveldt, Jeroen S.; Klein, Susanne; Leach, Edward; Pizzey, Claire; Richardson, Robert M.

    2005-04-01

    Suspensions of three different clays in K15, a thermotropic liquid crystal, have been studied by optical microscopy and small angle x-ray scattering. The three clays were claytone AF, a surface treated natural montmorillonite, laponite RD, a synthetic hectorite, and mined sepiolite. The claytone and laponite were sterically stabilized whereas sepiolite formed a relatively stable suspension in K15 without any surface treatment. Micrographs of the different suspensions revealed that all three suspensions contained large scale structures. The nature of these aggregates was investigated using small angle x-ray scattering. For the clays with sheet-like particles, claytone and laponite, the flocs contain a mixture of stacked and single platelets. The basal spacing in the stacks was independent of particle concentration in the suspension and the phase of the solvent. The number of platelets in the stack and their percentage in the suspension varied with concentration and the aspect ratio of the platelets. The lath shaped sepiolite did not show any tendency to organize into ordered structures. Here the aggregates are networks of randomly oriented single rods.

  7. Large scale structures in liquid crystal/clay colloids

    International Nuclear Information System (INIS)

    Duijneveldt, Jeroen S van; Klein, Susanne; Leach, Edward; Pizzey, Claire; Richardson, Robert M

    2005-01-01

    Suspensions of three different clays in K15, a thermotropic liquid crystal, have been studied by optical microscopy and small angle x-ray scattering. The three clays were claytone AF, a surface treated natural montmorillonite, laponite RD, a synthetic hectorite, and mined sepiolite. The claytone and laponite were sterically stabilized whereas sepiolite formed a relatively stable suspension in K15 without any surface treatment. Micrographs of the different suspensions revealed that all three suspensions contained large scale structures. The nature of these aggregates was investigated using small angle x-ray scattering. For the clays with sheet-like particles, claytone and laponite, the flocs contain a mixture of stacked and single platelets. The basal spacing in the stacks was independent of particle concentration in the suspension and the phase of the solvent. The number of platelets in the stack and their percentage in the suspension varied with concentration and the aspect ratio of the platelets. The lath shaped sepiolite did not show any tendency to organize into ordered structures. Here the aggregates are networks of randomly oriented single rods

  8. Synthesis of Zeolite A from Kaolin (Shwe Taung Clay)

    International Nuclear Information System (INIS)

    Mie Mie Han Htun; Mu Mu Htay

    2010-12-01

    The synthesis of Zeolite A from locally available kaolin clay (Shwe Taung) in Myanmar has been attempted. The kaolinite was converted to metakaoli, by treating with NaOH at 820C for 1hr, and hydrothermal treatment.It was found that the solution of fused clay powder can be crystallized at 100C under ambient pressure to synthesize Zeolite A. The process variables for synthesis have been optimized in order to produce Zeolite A at a lower price. The mole ratio of SiO2/Al2O3 for kaolin was fixed at 2.54. The effects of various factors (aging time and agitation time) on the structure of the sample were extensively investigated. The Shwe Taung clay was characterized by X-ray Diffraction (XRD), X-ray fluorescence (XRF) and Scanning Electron Microscopy (SEM). The samples were characterized by XRD. The results show that the pure form Zeolite A can be prepared with a molar composition of (2.54 SiO3: Al2O3: 5.8Na2O: 256 H2O) by agitation at room temperature for 30min. The mixture was aged for 24 hour at the same temperature and crystallized at 100C for 48 hour.

  9. Properties of fired clay brick incorporating with sewage sludge waste

    Science.gov (United States)

    Kadir, Aeslina Abdul; Salim, Nurul Salhana Abdul; Sarani, Noor Amira; Rahmat, Nur Aqma Izurin; Abdullah, Mohd Mustafa Al Bakri

    2017-09-01

    The production of sludge in wastewater treatment plant is about to increase every year and most of the sludge was directly disposed to landfill. In addition, the constraint to treat sludge is very high in cost and time- consuming could be disadvantages to the responsible parties. Therefore, this research was conducted to utilize sludge produced from the wastewater treatment plant into fired clay brick as one of the alternatives of disposal method. In this study, the research attempt to incorporate sewage sludge waste (SSW) into fired clay brick. The sewage sludge brick (SSB) mixtures were incorporated with 0%, 1%, 5%, 10%, and 20% of SSW. The manufactured bricks were fired at 1050°C with heating rate of 1°C/min. Physical and mechanical properties test were conducted such as shrinkage, density, water absorption and compressive strength. As the conclusion, brick with utilization 5% of SSW is acceptable to produce good quality of brick. This study shows by using SSW in fired clay brick could be an alternative method to dispose of the SSW and also could act as a replacement material for brick manufacturing with appropriate mix and design.

  10. Compressibility characteristics of Sabak Bernam Marine Clay

    Science.gov (United States)

    Lat, D. C.; Ali, N.; Jais, I. B. M.; Baharom, B.; Yunus, N. Z. M.; Salleh, S. M.; Azmi, N. A. C.

    2018-04-01

    This study is carried out to determine the geotechnical properties and compressibility characteristics of marine clay collected at Sabak Bernam. The compressibility characteristics of this soil are determined from 1-D consolidation test and verified by existing correlations by other researchers. No literature has been found on the compressibility characteristics of Sabak Bernam Marine Clay. It is important to carry out this study since this type of marine clay covers large coastal area of west coast Malaysia. This type of marine clay was found on the main road connecting Klang to Perak and the road keeps experiencing undulation and uneven settlement which jeopardise the safety of the road users. The soil is indicated in the Generalised Soil Map of Peninsular Malaysia as a CLAY with alluvial soil on recent marine and riverine alluvium. Based on the British Standard Soil Classification and Plasticity Chart, the soil is classified as a CLAY with very high plasticity (CV). Results from laboratory test on physical properties and compressibility parameters show that Sabak Bernam Marine Clay (SBMC) is highly compressible, has low permeability and poor drainage characteristics. The compressibility parameters obtained for SBMC is in a good agreement with other researchers in the same field.

  11. Sorption of radionuclides by tertiary clays

    International Nuclear Information System (INIS)

    Wagner, J.F.; Czurda, K.A.

    1990-01-01

    The sorption capacity of different clay types for some metals (Co, Cs, Sr and Zn), occurring as common radionuclides in radioactive waste deposits, had been analysed by a static (batch technique) and a dynamic method (percolation tests, in which the driving force is a hydraulic gradient). Sorption capacity generally increased with an increasing pH of solution. A decrease of sorption capacity had been observed in the order Zn > Cs ≥ Co > Sr for the batch and Cs > Zn > Sr > Co for the percolation tests. Clay marls showed a distinctly higher sorption respectively retention capacity as pure clays. Sorption capacity depends on solution parameters like type and concentration of radionuclide, pH, salt concentration, etc., and on rock parameters like mineral content (e.g. swelling clay minerals and carbonates), organic material, rock pH, micro fabric, etc. A third parameter of great influence is the contact time between clay and solution. The adsorption isotherms reflect two different adsorption mechanisms: a very rapid adsorption (a few minutes) on the external surfaces of clay minerals and a slow adsorption process (weeks and longer), due to the diffusion of metal ions into the interlayer space of clay minerals. 12 refs., 9 figs., 1 tab

  12. High Concentration of Red Clay as an Alternative for Antibiotics in Aquaculture.

    Science.gov (United States)

    Jung, Jaejoon; Jee, Seung Cheol; Sung, Jung-Suk; Park, Woojun

    2016-01-01

    The use of antibiotics in aquaculture raises environmental and food safety concerns because chronic exposure of an aquatic ecosystem to antibiotics can result in the spread of antibiotic resistance, bioaccumulation of antibiotics in the organisms, and transfer of antibiotics to humans. In an attempt to overcome these problems, high-concentration red clay was applied as an alternative antibiotic against the following common fish pathogens: Aeromonas salmonicida, Vibrio alginolyticus, and Streptococcus equinus. The growth of A. salmonicida and V. alginolyticus was retarded by red clay, whereas that of S. equinus was promoted. Phase contrast and scanning electron microscopy analyses confirmed the attachment of red clay on cell surfaces, resulting in rapid gravitational removal and cell surface damage in both A. salmonicida and V. alginolyticus, but not in S. equinus. Different cell wall properties of grampositive species may explain the unharmed cell surface of S. equinus. Significant levels of oxidative stress were generated in only the former two species, whereas significant changes in membrane permeability were found only in S. equinus, probably because of its physiological adaptation. The bacterial communities in water samples from Oncorhynchus mykiss aquacultures supplemented with red clay showed similar structure and diversity as those from oxytetracycline-treated water. Taken together, the antibiotic effects of high concentrations of red clay in aquaculture can be attributed to gravitational removal, cell surface damage, and oxidative stress production, and suggest that red clay may be used as an alternative for antibiotics in aquaculture.

  13. Deformation and Fabric in Compacted Clay Soils

    Science.gov (United States)

    Wensrich, C. M.; Pineda, J.; Luzin, V.; Suwal, L.; Kisi, E. H.; Allameh-Haery, H.

    2018-05-01

    Hydromechanical anisotropy of clay soils in response to deformation or deposition history is related to the micromechanics of platelike clay particles and their orientations. In this article, we examine the relationship between microstructure, deformation, and moisture content in kaolin clay using a technique based on neutron scattering. This technique allows for the direct characterization of microstructure within representative samples using traditional measures such as orientation density and soil fabric tensor. From this information, evidence for a simple relationship between components of the deviatoric strain tensor and the deviatoric fabric tensor emerge. This relationship may provide a physical basis for future anisotropic constitutive models based on the micromechanics of these materials.

  14. Discrete analysis of clay layer tensile strength

    International Nuclear Information System (INIS)

    Le, T.N.H.; Ple, O.; Villard, P.; Gourc, J.P.

    2010-01-01

    The Discrete Element Method is used to investigate the tensile behaviour and cracks mechanisms of a clay material submitted to bending loading. It is the case of compacted clay liners in landfill cap cover application. Such as the soil tested in this study is plastic clay, the distinct elements model was calibrated with previous data results by taking into account cohesive properties. Various contact and cohesion laws are tested to show that the numerical model is able to reproduce the failure mechanism. Numerical results are extending to simulate a landfill cap cover and comparing to experimental large scale field bending tests achieved in a real site of storage. (authors)

  15. Clay nanoparticles for regenerative medicine and biomaterial design: A review of clay bioactivity.

    Science.gov (United States)

    Mousa, Mohamed; Evans, Nicholas D; Oreffo, Richard O C; Dawson, Jonathan I

    2018-03-01

    Clay nanoparticles, composites and hydrogels are emerging as a new class of biomaterial with exciting potential for tissue engineering and regenerative medicine applications. Clay particles have been extensively explored in polymeric nanocomposites for self-assembly and enhanced mechanical properties as well as for their potential as drug delivery modifiers. In recent years, a cluster of studies have explored cellular interactions with clay nanoparticles alone or in combination with polymeric matrices. These pioneering studies have suggested new and unforeseen utility for certain clays as bioactive additives able to enhance cellular functions including adhesion, proliferation and differentiation, most notably for osteogenesis. This review examines the recent literature describing the potential effects of clay-based nanomaterials on cell function and examines the potential role of key clay physicochemical properties in influencing such interactions and their exciting possibilities for regenerative medicine. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Diffusion through statically compacted clay

    International Nuclear Information System (INIS)

    Ho, C.L.; Shebl, M.A.A.

    1994-01-01

    This paper presents experimental work on the effect of compaction on contaminant flow through clay liners. The experimental program included evaluation of soil properties, compaction, permeability and solute diffusion. A permeameter was built of non reactive materials to test samples compacted at different water contents and compactive efforts. The flow of a permeating solute, LiCl, was monitored. Effluent samples were collected for solute concentration measurements. The concentrations were measured by performing atomic adsorption tests. The analyzed results showed different diffusion characteristics when compaction conditions changed. At each compactive effort, permeability decreased as molding water content increased. Consequently, transit time (measured at relative concentration 50%) increased and diffusivity decreased. As compactive effort increased for soils compacted dry of optimum, permeability and diffusion decreased. On the other hand, as compactive effort increased for soils compacted wet of optimum, permeability and diffusivity increased. Tortuosity factor was indirectly measured from the diffusion and retardation rate. Tortuosity factor also decreased as placement water content was increased from dry of optimum to wet of optimum. Then decreases were more pronounced for low compactive effort tests. 27 refs., 7 figs., 5 tabs

  17. Fracture in Kaolinite clay suspensions

    Science.gov (United States)

    Kosgodagan Acharige, Sebastien; Jerolmack, Douglas J.; Arratia, Paulo E.

    2017-11-01

    Clay minerals are involved in many natural (landslides, river channels) and industrial processes (ceramics, cosmetics, oil recovery). They are plate shaped charged colloids and exhibit different flow properties than simpler colloids when suspended in a liquid such as thixotropy and shear-banding. kaolinite platelets are non-swelling, meaning that the stacks formed by the platelets do not have water layers, and thus the suspension does not have a sol-gel transition. However, it has been shown that kaolinite suspensions possesses a non-zero yield stress even at low concentrations, indicating that the particles arrange themselves in a structure through attractive interactions. Here, we experimentally investigate the sedimentation of kaolinite suspensions in a Hele-Shaw cell. The sedimentation of these dilute suspensions can display solid behavior like fracture, revealed in cross-polarized light, which is linked to the failure of the weakly-bonded structure (typical yield stress 10-2 Pa). By changing the interaction potential of the particles (by sonication or introducing salts), we show through these sedimentation experiments, how the fracture pattern can be avoided. Research was sponsored by the Army Research Laboratory and was accomplished under Grant Number 569074.

  18. Clay-free drilling mud

    Energy Technology Data Exchange (ETDEWEB)

    Akhmadeyev, R G; Panov, V B; Simonenkov, O I

    1982-01-01

    A clay-free drilling mud is proposed which contains humate-containing substance, alkali electrolyte, gel-former, inhibitor and water. In order to reduce viscosity of the static shear stress and water output under conditions of polyvalent aggression, it additionally contains organic stabilizer with the following ratio of components, % by mass: humate-containing substance 4.0-8.0; alkali electrolyte 0.2-1.5; gel-former 1.0-3.0; organic stabilizer 0.1-1.0; inhibitor 1.0-40.0; water--the rest. The solution is also distinguished by the fact that the gel-former used is magnesium chloride or magnesium sulfate, or calcium chloride or aluminum sulfate, or iron chloride (III) or iron sulfate (II) or waste of chlorides of titanium production with average chemical composition, % by mass: Ti 1.5-7.0; Fe 5.0-15.0; Al 1.5-10.0; Na 5.0-16.0; Mg 0.5-3.0; Cl 30.0-60.0; Ca 0.2-2.0; Cr 0.2-2.0; Cu 0.2-1.5.

  19. Radionuclides sorption in clay soils

    International Nuclear Information System (INIS)

    Siraky, G.; Lewis, C.; Hamlat, S.; Nollmann, C.E.

    1987-01-01

    The sorption behaviour of clay soils is examined through a parametric study of the distribution coefficient (Kd) for the radionuclides of interest, Cs and Sr. This work is a preliminary stage of the migration studies of these nuclides in a porous medium (ground of Ezeiza, Argentina) and the evaluation of radiologic impact of the removal of low and intermediate activity wastes in shallow trenches. The determination of Kd is performed by a static technique or batch. The phases are separated by centrifugation at 20000 g during 1 hour. The activity of supernatant solution of Cs-137 and Sr-85 is measured in a detecting system of I Na(Tl) well-type. Two types of parameters were changed: a) those related to the determination method: phase separation (centrifugation vs. centrifugation plus filtration); equilibrium period, ratio solid/liquid; b) those related to the geochemical system: pH of contact solution, carrier concentration, competitive ions, ionic strength, desorption. It was observed that the modification of parameters in the Kd-measurement does not change the order of magnitude of results. (Author)

  20. Release of cadmium from clays and plant uptake of cadium from soil as affected by potassium and calcium amendments

    International Nuclear Information System (INIS)

    Haghiri, F.

    1976-01-01

    The effects of percent K and/or Ca saturations on the release of Cd from Cd-treated H-clays (kaolinite and illite) and on the Cd availability to plants from Cd-treated Canfield silt loam soil were determined. The concentration of Cd in the dialyzates from both kaolinite and illite clays increased as the percent of Ca or K saturation of the clays in the suspension decreased. The release of Cd from both clays was greater in the presence of Ca than K. In a separate experiment, the concentration of Cd in soybean shoots (Glycine max L. Merr.) ''Corsoy'' decreased with increasing percent Ca or K saturation of the soil. The results indicated that Cd uptake by soybeam shoots could be impaired to a great extent by K application

  1. Geochemical and mineralogical characteristics of Lithomargic clay

    African Journals Online (AJOL)

    Administrator

    Geochemical and mineralogical characteristics of Lithomargic clay. GEOCHEMICAL AND .... tries, as filling material in the pulp and paper, toothpaste and paint industries as well ..... tions very vital to human health and other ac- tivities of man.

  2. Study of radionuclide migration in clay formations

    International Nuclear Information System (INIS)

    Antonioli, F.; Bocola, W.

    1985-01-01

    This paper reports the studies on the migration of Cs, Sr and I in clay formations, which are presently considered for the geological disposal of radioactive wastes. The distribution and diffusion coefficients were evaluated by means of experimental techniques and computer procedures, which are presented in this report. The natural clays tested in the laboratory experiments were sampled from the most representative italian basins and from the zone of Mol (Belgium). In addition tests were performed on monomineral clays artificially remade in edometer. The experimental results are in accordance with data found in the literature and show the existence of a good correlation between the observed migration properties and the granulometric and mineralogic characteristics of the natural clays

  3. pillared and un-pillared bentonite clays

    African Journals Online (AJOL)

    BARTH EKWUEME

    2011-07-29

    Jul 29, 2011 ... A pseudo-second order kinetic model was used to characterize the metal ion transport ... may endanger human health through consumption of sea food and ... widely reported. The pillared clays are two – dimensional zeolite.

  4. experimental characterization of clay soils behavior stabilized

    African Journals Online (AJOL)

    S. Rehab Bekkouche, G. Boukhatem

    2016-09-01

    Sep 1, 2016 ... California Bearing Ratio (CBR) ... the globe. Clay soils have the curious property of seeing their consistency changes according ... The use of building materials had been popularly applied to soil stabilization, such as cement.

  5. Aspects of clay/concrete interactions

    International Nuclear Information System (INIS)

    Oscarson, D.W.; Dixon, D.A.; Onofrei, M.

    1997-01-01

    In the Canadian concept for nuclear fuel waste management, both clay-based materials and concrete are proposed for use as barriers, seals or supporting structures. The main concern when clays and concrete are in proximity is the generation of a high-pH environment by concrete since clay minerals are relatively unstable at high pH. Here we examine the OH - -generating capacity of two high-performance concretes when in contact with several solutions. We also investigate various aspects of claylconcrete interactions. They are: (1) the alkalimetric titration of clay suspensions, (2) the effect of Ca(OH) 2 (portlandite) on the swelling and hydraulic properties of compacted bentonite, and (3) the influence of cement grout on a backfill clay retrieved from the 900-d Buffer/Container Experiment at the Underground Research Laboratory of AECL. The results indicate that although high-performance concretes establish significantly lower poresolution pH (9 to 10) than does ordinary portland cement, the pH is still somewhat higher than that of clay/groundwater systems of about pH 8. Hence, even if high-performance concrete is used in a disposal vault, the potential still exists for clay minerals to alter over long periods of time if in contact with this concrete. The data show, however, that clays have a substantial buffering capacity, and clay-based barriers can thus neutralize much of the OH - potentially released from concrete in a vault. Moreover, even after reacting for 120 d at 85 o C with up to 5 wt.% Ca(OH) 2 , compacted bentonite (dry density = 1.2 Mg/m 3 ) retains much of its swelling capacity and has a permeability low enough (hydraulic conductivity ≤ 10 -11 m/s) to ensure that molecular diffusion will be the main transport mechanism through compacted clay-based barriers. Furthermore, according to X-ray diffractometry, the clay mineral component of backfill was not altered by contact with a cement grout for 900 d in the Buffer/Container Experiment

  6. Stabilisation of Clay Soil with Lime and Melon Husk Ash for use in Farm Structures

    Directory of Open Access Journals (Sweden)

    I. S. Mohammed

    2014-08-01

    Full Text Available The rising cost of traditional stabilising agents and the need for economical utilisation of industrial and agricultural waste for beneficial engineering purposes has encouraged an investigation into the stabilization of clay soil with lime and melon husk ash. The chemical composition of the melon husk ash that was used in stabilising clay soil was determined. The clay soil was divided into two parts, one part was used to determine the index properties while the other part was treated at British Standard Light (BSL compaction energy with 0 %, 2 %, 4 %, 6 % and 8 % melon husk ash by dry weight of the soil and each was admixed with 2 %, 4 %, 6 % and 8 % lime. The stabilised clay soil was cured for 7, 14 and 28 days before the unconfined compressive strength were determined while the coefficients of permeability of the stabilised clay soil were also determined at 28 days of curing. The data obtained from the experiment was subjected to analysis of variance to examine the significance at 5% level. Results showed that the natural clay soil belong to A-7-6 or CH (clay of high plasticity in the American Association of State Highway Transportation Official (AASHTO and Unified Soil Classification System (1986. The chemical composition of the ash had aluminum oxide, iron oxide and silicon dioxide values of 18.5%, 2.82% and 51.24% respectively. The unconfined compressive strength and coefficient of permeability of the natural clay soil was determined to be 285 kN/m2 and 1.45 x 10-5 cm/s, respectively. Increase in melon husk ash and lime percent increases the unconfined compressive strength (UCS of the stabilised clay soil significantly (p < 0.05 and decrease the coefficient of permeability when compared with the natural clay soil. The peak values of unconfined compressive strength for 7, 14 and 28 days of curing are 1200 kN/m2, 1598 kN/m2 and 1695 kN/m2 respectively at 6% MHA and 8% lime content while the lowest value for coefficient of permeability was 0

  7. Bentonite clay purification for development of polymeric nan composites using a single screw extruder; Purificacao de argila bentonita para desenvolvimento de nanocomposito polimerico utilizando uma extrusora rosca simples

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    In this work, a bentonite clay rich in montmorillonite was purified and chemical treat to be used in the development of poly (methyl methacrylate) /clay nanocomposites via melting processes. After the clay treatment and purification, a masterbatch with 25% clay and 75% PMMA was produced by solution technique, using acetone as solvent. For produce samples with 2.5% clay, the masterbatch along with pure polymer were added and mixed in single screw extruder with a diameter of 16 mm and W/D 26. X-rays diffractometry (XRD) and X-rays fluorescence (XRF). Tests were performed to evaluate and characterizing the bentonite clay used in the development of this work and differential scanning calorimetry (DSC) tests were performed to evaluate changes in the thermal properties of the nanocomposites produced. (author)

  8. Quantifying the effect of squirt flow dispersion from compliant clay porosity in clay bearing sandstones

    DEFF Research Database (Denmark)

    Sørensen, Morten Kanne; Fabricius, Ida Lykke

    2013-01-01

    Compliant porosity in the form of cracks is known to cause significant attenuation and velocity dispersion through pore pressure gradients and consequent relaxation, dubbed squirt flow. Squirt flow from cracks vanish at high confining stress due to crack closing. Studies on clay bearing sandstones......-squirt flow on the bulk modulus of a clay bearing sandstone. The predicted magnitude of the clay-squirt effect on the bulk modulus is compared with experimental data. The clay-squirt effect is found to possibly account for a significant portion of the deviances from Gassmann fluid substitution in claybearing...... sandstones....

  9. Electrical and Thermo-Mechanical properties of Irradiated Clay Nanoparticle/SBR Composites

    International Nuclear Information System (INIS)

    Ata, M.M.E.M.

    2011-01-01

    Polymer-Composites incorporating metal, semiconductors, Carbon black, nano materials and Clay materials have been widely used and studied as multifunctional materials with inherent polymer properties. Polymer-clay nano composites show remarkable property improvement when compared to conventionally scaled composites. For designing new materials with desirable, predicted properties, a better understanding of structure-property relationships is necessary. In this work, we employ dielectric relaxation spectroscopy (DRS) to investigate molecular mobility in relation to morphology in styrene butadiene rubber-SBR (treated and untreated) nano composites. In addition to the investigation of dipolar processes, special attention is paid here to the investigation of conductivity effects and mechanical as well as thermo-mechanical properties. From the stress-strain characteristics, one found that, all the compositions showed a tensile strength higher than the virgin rubber. By increasing the filler loading, the tensile strength of the prepared composites increases. The elongation at break for treated and untreated clay filed composites increases with an increase in filer loading up to 10 p hr and then followed by a decrease up to 15 p hr. The cross linking density, υ increases with both treated and untreated clay contents and treated samples have higher increasing rate of υ values than untreated one. To elucidate the tensile behavior of the test samples. The Ht model is tested by using non-Gaussian chain statistics, which give a good fitting with the experimental data.

  10. Calcium montmorillonite clay for the reduction of aflatoxin residues in milk and dairy products

    Science.gov (United States)

    In this study, dairy cows were treated with calcium montmorillonite clay (NovaSil Plus (NSP); BASF Corp., Ludwigshaven, Germany) in a replicated 5x5 Latin square design. The primary objectives were to determine if milk composition was altered following ingestion of NSP, and to investigate the abili...

  11. Pedological ~cterization, Clay Mine:at~ and .~cation of,

    African Journals Online (AJOL)

    namely, very deep, well drained, dark reddish brown to dark brown, sandy clay loams and sandy clays on the steep convex slopes; very deep, well drained, dark brown to dark red, sandy clay loams and; sandy clays on the linear slopes; and very ...

  12. Utilization of Nkpuma-Akpatakpa clay in ceramics: characterization ...

    African Journals Online (AJOL)

    Nkpuma – Akpatakpa clay was analysed for its ceramics suitability. Chemical, mechanical and spectral characterization of the clay was carried out to obtain more information from this clay found in commercial quantity at Ebonyi State Nigeria. The XRD analysis showed that the principal minerals in the clay are quartz, ...

  13. Preparation and properties of recycled HDPE/clay hybrids

    Science.gov (United States)

    Yong Lei; Qinglin Wu; Craig M. Clemons

    2007-01-01

    Hybrids based on recycled high density polyethylene (RHDPE) and organic clay were made by melt compounding. The influence of blending method, compatibilizers, and clay content on clay intercalation and exfoliation, RHDPE crystallization behavior, and the mechanical properties of RHDPE/clay hybrids were investigated. Both maleated polyethylene (MAPE) and titanate could...

  14. The Composition and Physical Properties of Some Clays of Cross ...

    African Journals Online (AJOL)

    ... and quartz as the main subsidiary non-clay mineral. The high plasticity index of the clays corresponds to the more transported clays of the tertiary- to –recent environment. The percentage of linear shrinkage varied from 11-16% with the lowest shrinkage (11%), having the coarsest features. Silica (SiO2) content of the clays ...

  15. What Makes a Natural Clay Antibacterial?

    Science.gov (United States)

    Williams, Lynda B.; Metge, David W.; Eberl, Dennis D.; Harvey, Ronald W.; Turner, Amanda G.; Prapaipong, Panjai; Poret-Peterson, Amisha T.

    2011-01-01

    Natural clays have been used in ancient and modern medicine, but the mechanism(s) that make certain clays lethal against bacterial pathogens has not been identified. We have compared the depositional environments, mineralogies, and chemistries of clays that exhibit antibacterial effects on a broad spectrum of human pathogens including antibiotic resistant strains. Natural antibacterial clays contain nanoscale (clay minerals in the bactericidal process is to buffer the aqueous pH and oxidation state to conditions that promote Fe2+ solubility. Chemical analyses of E. coli killed by aqueous leachates of an antibacterial clay show that intracellular concentrations of Fe and P are elevated relative to controls. Phosphorus uptake by the cells supports a regulatory role of polyphosphate or phospholipids in controlling Fe2+. Fenton reaction products can degrade critical cell components, but we deduce that extracellular processes do not cause cell death. Rather, Fe2+ overwhelms outer membrane regulatory proteins and is oxidized when it enters the cell, precipitating Fe3+ and producing lethal hydroxyl radicals. PMID:21413758

  16. Quality evaluation of processed clay soil samples.

    Science.gov (United States)

    Steiner-Asiedu, Matilda; Harrison, Obed Akwaa; Vuvor, Frederick; Tano-Debrah, Kwaku

    2016-01-01

    This study assessed the microbial quality of clay samples sold on two of the major Ghanaian markets. The study was a cross-sectional assessing the evaluation of processed clay and effects it has on the nutrition of the consumers in the political capital town of Ghana. The items for the examination was processed clay soil samples. Staphylococcus spp and fecal coliforms including Klebsiella, Escherichia, and Shigella and Enterobacterspp were isolated from the clay samples. Samples from the Kaneshie market in Accra recorded the highest total viable counts 6.5 Log cfu/g and Staphylococcal count 5.8 Log cfu/g. For fecal coliforms, Madina market samples had the highest count 6.5 Log cfu/g and also recorded the highest levels of yeast and mould. For Koforidua, total viable count was highest in the samples from the Zongo market 6.3 Log cfu/g. Central market samples had the highest count of fecal coliforms 4.6 Log cfu/g and yeasts and moulds 6.5 Log cfu/g. "Small" market recorded the highest staphylococcal count 6.2 Log cfu/g. The water activity of the clay samples were low, and ranged between 0.65±0.01 and 0.66±0.00 for samples collected from Koforidua and Accra respectively. The clay samples were found to contain Klebsiella spp. Escherichia, Enterobacter, Shigella spp. staphylococcus spp., yeast and mould. These have health implications when consumed.

  17. Soil clay content underlies prion infection odds

    Science.gov (United States)

    David, Walter W.; Walsh, D.P.; Farnsworth, Matthew L.; Winkelman, D.L.; Miller, M.W.

    2011-01-01

    Environmental factors-especially soil properties-have been suggested as potentially important in the transmission of infectious prion diseases. Because binding to montmorillonite (an aluminosilicate clay mineral) or clay-enriched soils had been shown to enhance experimental prion transmissibility, we hypothesized that prion transmission among mule deer might also be enhanced in ranges with relatively high soil clay content. In this study, we report apparent influences of soil clay content on the odds of prion infection in free-ranging deer. Analysis of data from prion-infected deer herds in northern Colorado, USA, revealed that a 1% increase in the clay-sized particle content in soils within the approximate home range of an individual deer increased its odds of infection by up to 8.9%. Our findings suggest that soil clay content and related environmental properties deserve greater attention in assessing risks of prion disease outbreaks and prospects for their control in both natural and production settings. ?? 2011 Macmillan Publishers Limited. All rights reserved.

  18. Use of clays as liners in solar ponds

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Gerardo [Facultad de Ingenieria, Universidad Anahuac Mexico Norte, Huixquilucan, Edo. de Mexico 52786 (Mexico); Almanza, Rafael [Instituto de Ingenieria, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico D.F. 04510 (Mexico)

    2009-06-15

    An alternative to synthetic materials for use in solar pond liners is to select clayey soils as hydraulic barriers. This option reduces the cost of construction and the risk of contamination of subsoil and groundwater by hot brines. This paper deals with the physical, chemical and hydraulic properties of different soils tested mainly as compacted clay liners. The underdeveloped nations have the option to use this type of liner, but before doing so several tests are recommended, including those for soil and water composition, permeability, plasticity and X-ray diffraction analysis. In this investigation the following samples are analyzed: native clayey soils with illite, montmorillonite and halloysite, treated and non-treated bentonites in powder and granulated form, a mixture of zeolite and sodium bentonite, and industrial minerals composed largely of halloysite, kaolinite and attapulgite selected clays. Neutral salt aqueous solutions (NaCl and KCl) at different concentrations and under temperature gradients were used for compatibility testing conducted on these specimens. Experiment setup and particular testing procedures are also discussed. (author)

  19. Characterization of clay used for red ceramic fabrication

    International Nuclear Information System (INIS)

    Pereira, P.S.; Morais, A.S.C.; Caldas, T.C.C.; Monteiro, S.N.; Vieira, C.M.F.

    2011-01-01

    The objective of this work is to characterize a clay used in the red ceramics fabrication, from Campos dos Goytacazes north of the State of Rio de Janeiro. The clay was submitted for physical, chemical and mineralogical tests. The results showed that the clay has a high content of clay minerals with kaolinitic predominance, high loss on ignition and low flux oxides. It is recommended that this clay is mixed with non-plastic materials. (author)

  20. Effects of modified Clay on the morphology and thermal stability of PMMA/clay nanocomposites

    International Nuclear Information System (INIS)

    Tsai, Tsung-Yen; Lin, Mei-Ju; Chuang, Yi-Chen; Chou, Po-Chiang

    2013-01-01

    The potential to improve the mechanical, thermal, and optical properties of poly(methyl methacrylate) (PMMA)/clay nanocomposites prepared with clay containing an organic modifier was investigated. Pristine sodium montmorillonite clay was modified using cocoamphodipropionate, which absorbs UVB in the 280–320 nm range, via ion exchange to enhance the compatibility between the clay platelets and the methyl methacrylate polymer matrix. PMMA/clay nanocomposites were synthesized via in situ free-radical polymerization. Three types of clay with various cation-exchange capacities (CEC) were used as inorganic layered materials in these organic–inorganic hybrid nanocomposites: CL42, CL120, and CL88 with CEC values of 116, 168, and 200 meq/100 g of clay, respectively. We characterized the effects of the organoclay dispersion on UV resistance, effectiveness as an O 2 gas barrier, thermal stability, and mechanical properties of PMMA/clay nanocomposites. Gas permeability analysis demonstrated the excellent gas barrier properties of the nanocomposites, consistent with the intercalated or exfoliated morphologies observed. The optical properties were assessed using UV–Visible spectroscopy, which revealed that these materials have good optical clarity, UV resistance, and scratch resistance. The effect of the dispersion capability of organoclay on the thermal properties of PMMA/clay nanocomposites was investigated by thermogravimetric analysis and differential scanning calorimetry; these analyses revealed excellent thermal stability of some of the modified clay nanocomposites. - Highlights: ► We control the dispersion morphology by protonation of K2 into the clay. ► The CL120 and CL88, with the higher CEC, are more random intercalated by K2. ► We report these materials have good optical clarity, and UV resistance

  1. Silt-clay aggregates on Mars

    International Nuclear Information System (INIS)

    Greeley, R.

    1979-01-01

    Viking observations suggest abundant silt and clay particles on Mars. It is proposed that some of these particles agglomerate to form sand size aggregates that are redeposited as sandlike features such as drifts and dunes. Although the binding for the aggregates could include salt cementation or other mechanisms, electrostatic bonding is considered to be a primary force holding the aggregates together. Various laboratory experiments conducted since the 19th century, and as reported here for simulated Martian conditions, show that both the magnitude and sign of electrical charges on windblown particles are functions of particle velocity, shape and composition, atmospheric pressure, atmospheric composition, and other factors. Electrical charges have been measured for saltating particles in the wind tunnel and in the field, on the surfaces of sand dunes, and within dust clouds on earth. Similar, and perhaps even greater, charges are proposed to occur on Mars, which could form aggregates of silt and clay size particles. Electrification is proposed to occur within Martian dust clouds, generating silt-clay aggregates which would settle to the surface where they may be deposited in the form of sandlike structures. By analog, silt-clay dunes are known in many parts of the earth where silt-clay aggregated were transported by saltation and deposited as 'sand.' In these structures the binding forces were later destroyed, and the particles reassumed the physical properties of silt and clay, but the sandlike bedding structure within the 'dunes' was preserved. The bedding observed in drifts at the Viking landing site is suggested to result from a similar process involving silt-clay aggregates on Mars

  2. Influence of Polymer-Clay Interfacial Interactions on the Ignition Time of Polymer/Clay Nanocomposites.

    Science.gov (United States)

    Zope, Indraneel S; Dasari, Aravind; Yu, Zhong-Zhen

    2017-08-11

    Metal ions present on smectite clay (montmorillonite) platelets have preferential reactivity towards peroxy/alkoxy groups during polyamide 6 (PA6) thermal decomposition. This changes the decomposition pathway and negatively affects the ignition response of PA6. To restrict these interfacial interactions, high-temperature-resistant polymers such as polyetherimide (PEI) and polyimide (PI) were used to coat clay layers. PEI was deposited on clay by solution-precipitation, whereas PI was deposited through a solution-imidization-precipitation technique before melt blending with PA6. The absence of polymer-clay interfacial interactions has resulted in a similar time-to-ignition of PA6/PEI-clay (133 s) and PA6/PI-clay (139 s) composites as neat PA6 (140 s). On the contrary, PA6 with conventional ammonium-based surfactant modified clay has showed a huge drop in time-to-ignition (81 s), as expected. The experimental evidences provided herein reveal the role of the catalytic activity of clay during the early stages of polymer decomposition.

  3. Mechanical interaction between swelling compacted clay and fractured rock, and the leaching of clay colloids

    NARCIS (Netherlands)

    Grindrod, P.; Peletier, M.A.; Takase, H.

    1999-01-01

    We consider the interaction between a saturated clay buffer layer and a fractured crystalline rock engineered disturbed zone. Once saturated, the clay extrudes into the available rock fractures, behaving as a compressible non-Newtonian fluid. We discuss the modelling implications of published

  4. Removal of remazol yellow with modified clays with iron

    International Nuclear Information System (INIS)

    Diaz-Gomez T, A. P.

    2012-01-01

    Clays have the ability to absorb water and to retain in its structure both hydrophilic and hydrophobic substances, therefore, it is possible to use them in the sorption of dyes from waste water, in order to avoid affecting water bodies or storm drains when they are discharged. In this paper the montmorillonite KSF and a sodium bentonite from the Morelos State, Mexico were studied for the sorption of an azo dye used in textiles knows as remazol yellow. These clays were modified with iron, the dye sorption behaviors and their regeneration processes for their reuse were determined. It was difficult to separate the sodium bentonite after being in contact with aqueous solutions; therefore it was nor a candidate dor the removal of remazol yellow from aqueous solutions. The montmorillonite KSF was characterized before and after the iron modification, and after its regeneration by scanning electron microscopy (elemental analysis), infrared spectrometry, X-ray diffraction, and the specific areas of the materials were determined by Bet analysis. The adsorption equilibrium time and the adsorption rate for remazol yellow were determined from the fitting of the experimental results to mathematical models for the unmodified and iron modified montmorillonite KSF. The adsorption capacity was determined from the adsorption isotherms and mathematical models. The influence of the ph in the sorption processes was determined as well, and it was found that, ph values between 2 and 12 do not have any influence on the adsorption processes for iron modified montmorillonite KSF. The montmorillonite KSF and the iron modified montmorillonite KSF are adequate adsorbents for the removal of remazol yellow from aqueous solutions. Although, the sorption capacity for the unmodified montmorillonite KSF is higher (about 10%) than the capacity for the iron modified montmorillonite KSF and the stability of the last one increased. The saturated clays with remazol yellow were treated with Fenton reactive

  5. Hydrogen isotope ratios of clay minerals constituting clay veins found in granitic rocks in Hiroshima Prefecture

    International Nuclear Information System (INIS)

    Kitagawa, Ryuji; Kakitani, Satoru; Kuroda, Yoshimatsu; Matsuo, Sadao; Suzuoki, Tetsuro.

    1980-01-01

    The deuterium content of the constitutional and interlayer water extracted from the clay minerals (illite, montmorillonite, interstratified illite-montmorillonite mineral, kaolinite, halloysite) constituting the clay veins found in the granitic rocks in Hiroshima Prefecture was measured. The clay minerals were heated at 270 deg C to extract the interlayer water, then heated to 1,400 or 1,500 deg C to extract the constitutional water. The deuterium content of the local surface water collected from sampling points was measured. In the clay veins formed along perpendicular joints, the constituent clay minerals change from lower to upper part: illite → montmorillonite → kaolinite → halloysite. The deuterium content values of the constitutional water for illite and montmorillonite were estimated to be -67 to -69% and -86 to -89%, respectively. The deuterium content values of the constitutional water for halloysite range from -68 to -80% and for kaolinite from -63 to -67%. (J.P.N.)

  6. Enchanted Clays: 44th Annual Meeting of the Clay Minerals Society (June 2007)

    Energy Technology Data Exchange (ETDEWEB)

    Randall T. Cygan

    2007-06-01

    “Enchanted Clays: 44th Annual Meeting of the Clay Minerals Society” was held in early June 2007 in beautiful and historic Santa Fe, New Mexico, USA. Santa Fe provided an idyllic location in the southwestern United States for the attendees to enjoy technical and social sessions while soaking up the diverse culture and wonderful climate of New Mexico—The Land of Enchantment. The meeting included a large and varied group of scientists, sharing knowledge and ideas, benefitting from technical interactions, and enjoying the wonderful historic and enchanted environs of Santa Fe. Including significant number of international scientists, the meeting was attended by approximately two hundred participants. The meeting included three days of technical sessions (oral and poster presentations), three days of field trips to clay and geological sites of northern New Mexico, and a full day workshop on the stabilization of carbon by clays. Details can be found at the meeting web site: www.sandia.gov/clay.

  7. Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

    Directory of Open Access Journals (Sweden)

    Youngmin Choi

    2016-12-01

    Full Text Available Water-repellent soils have a potential as alternative construction materials that will improve conventional geotechnical structures. In this study, the potential of chemically treated water-repellent kaolin clay as a landfill cover material is explored by examining its characteristics including hydraulic and mechanical properties. In order to provide water repellency to the kaolin clay, the surface of clay particle is modified with organosilanes in concentrations (CO ranging from 0.5% to 10% by weight. As the CO increases, the specific gravity of treated clay tends to decrease, whereas the total organic carbon content of the treated clay tends to increase. The soil-water contact angle increases with an increase in CO until CO = 2.5%, and then maintains an almost constant value (≈134.0°. Resistance to water infiltration is improved by organosilane treatment under low hydrostatic pressure. However, water infiltration resistance under high hydrostatic pressure is reduced or exacerbated to the level of untreated clay. The maximum compacted dry weight density decreases with increasing CO. As the CO increases, the small strain shear modulus increases, whereas the effect of organosilane treatment on the constrained modulus is minimal. The results indicate that water-repellent kaolin clay possesses excellent engineering characteristics for a landfill cover material.

  8. Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

    Science.gov (United States)

    Choi, Youngmin; Choo, Hyunwook; Yun, Tae Sup; Lee, Changho; Lee, Woojin

    2016-01-01

    Water-repellent soils have a potential as alternative construction materials that will improve conventional geotechnical structures. In this study, the potential of chemically treated water-repellent kaolin clay as a landfill cover material is explored by examining its characteristics including hydraulic and mechanical properties. In order to provide water repellency to the kaolin clay, the surface of clay particle is modified with organosilanes in concentrations (CO) ranging from 0.5% to 10% by weight. As the CO increases, the specific gravity of treated clay tends to decrease, whereas the total organic carbon content of the treated clay tends to increase. The soil-water contact angle increases with an increase in CO until CO = 2.5%, and then maintains an almost constant value (≈134.0°). Resistance to water infiltration is improved by organosilane treatment under low hydrostatic pressure. However, water infiltration resistance under high hydrostatic pressure is reduced or exacerbated to the level of untreated clay. The maximum compacted dry weight density decreases with increasing CO. As the CO increases, the small strain shear modulus increases, whereas the effect of organosilane treatment on the constrained modulus is minimal. The results indicate that water-repellent kaolin clay possesses excellent engineering characteristics for a landfill cover material. PMID:28774098

  9. Organic or organometallic template mediated clay synthesis

    Science.gov (United States)

    Gregar, Kathleen C.; Winans, Randall E.; Botto, Robert E.

    1994-01-01

    A method for incorporating diverse Varieties of intercalants or templates directly during hydrothermal synthesis of clays such as hectorite or montmorillonite-type layer-silicate clays. For a hectorite layer-silicate clay, refluxing a gel of silica sol, magnesium hydroxide sol and lithium fluoride for two days in the presence of an organic or organometallic intercalant or template results in crystalline products containing either (a) organic dye molecules such as ethyl violet and methyl green, (b) dye molecules such as alcian blue that are based on a Cu(II)-phthalocyannine complex, or (c) transition metal complexes such as Ru(II)phenanthroline and Co(III)sepulchrate or (d) water-soluble porphyrins and metalloporphyrins. Montmorillonite-type clays are made by the method taught by U.S. Pat. No. 3,887,454 issued to Hickson, Jun. 13, 1975; however, a variety of intercalants or templates may be introduced. The intercalants or templates should have (i) water-solubility, (ii) positive charge, and (iii) thermal stability under moderately basic (pH 9-10) aqueous reflux conditions or hydrothermal pressurized conditions for the montmorillonite-type clays.

  10. Accurate control testing for clay liner permeability

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, R J

    1991-08-01

    Two series of centrifuge tests were carried out to evaluate the use of centrifuge modelling as a method of accurate control testing of clay liner permeability. The first series used a large 3 m radius geotechnical centrifuge and the second series a small 0.5 m radius machine built specifically for research on clay liners. Two permeability cells were fabricated in order to provide direct data comparisons between the two methods of permeability testing. In both cases, the centrifuge method proved to be effective and efficient, and was found to be free of both the technical difficulties and leakage risks normally associated with laboratory permeability testing of fine grained soils. Two materials were tested, a consolidated kaolin clay having an average permeability coefficient of 1.2{times}10{sup -9} m/s and a compacted illite clay having a permeability coefficient of 2.0{times}10{sup -11} m/s. Four additional tests were carried out to demonstrate that the 0.5 m radius centrifuge could be used for linear performance modelling to evaluate factors such as volumetric water content, compaction method and density, leachate compatibility and other construction effects on liner leakage. The main advantages of centrifuge testing of clay liners are rapid and accurate evaluation of hydraulic properties and realistic stress modelling for performance evaluations. 8 refs., 12 figs., 7 tabs.

  11. Radionuclide sorption studies on abyssal red clays

    International Nuclear Information System (INIS)

    Erickson, K.L.

    1979-01-01

    The radionuclide sorption properties of a widely distributed abyssal red clay are being experimentally investigated using batch equilibration techniques. This paper summarizes sorption equilibrium data obtained when 0.68 N NaCl solutions containing either Tc, U, Pu, Am or Cm were contacted with samples of the red clay and also summarizes some initial results from experiments designed to determine the relative selectivity of the clay for various nuclides. Under mildly oxidizing conditions, the sorption equilibrium distribution coefficients for technetium were essentially zero. At solution-phase nuclide concentrations on the order of 10 -6 M and less and at solution pH values of about 6.9, the distribution coefficients for plutonium were about 3 x 10 3 m1/gm and for uranium, americium, and curium were about 10 5 ml/gm or greater. However, at solution pH values of about 2.7, the distribution coefficients for each of the nuclides were greatly diminished. Initial experiments conducted in order to determine the relative selectivity of the clay for cesium, barium, and cerium, indicated that the silicate phases in the clay were selective for cesium over barium and cerium. These experiments also indicated that the hydrous oxide phases were selective for cerium over barium and for barium over cesium

  12. Clay Treatment To Improve Its Color Parameters To Use Them In Porcelain Stoneware Production

    International Nuclear Information System (INIS)

    Llop, M.; Notari, M.D.; Barrachina, E.; Nebot, I.; Nunez, I.; Carda, J.B.

    2010-01-01

    The porcelain stoneware tiles production needs high whiteness clays in order to be competitive in the ceramic sector. In the present work, Spanish clays used in the porcelain stoneware tiles production have been characterized in physic, chemist and mineralogical terms, in order to reduce its content of chromophore oxides (Fe2O3 and TiO2). These reduction processes are concerned with different physical and chemical treatments, as sieving at 150mm, magnetic separation using a 0.6T permanent magnet, or acid treatment with HCL and later neutralization with NH3. With these treatments, due to siderite elimination, chromophore oxides as Fe2O3 have been decreased from 2,36% to 1,66% in the chemically treated clay. (Author).

  13. Characterization of clays used in the red ceramics industry at Itabaianinha-SE (Brazil)

    International Nuclear Information System (INIS)

    Azevedo, T.F.; Andrade, C.E.C. de; Santos, C.R. dos; Barreto, L.S.

    2011-01-01

    The Local Cluster of red ceramic industry in the state of Sergipe comprises Itabaianinha-SE, Itabaiana and Baixo Sao Francisco municipalities (Propria and Santana do Sao Francisco). The city of Itabaianinha concentrates a large number of ceramics and potteries producing ceramic bricks and tiles. The study was conducted in a red ceramic industry of the region. The focus of this work was an incremental innovation in the process and product. It was analyzed three types of clays used for manufacturing of ceramic bricks (barro preto, diamante and jardim). The samples were prepared by pressing and heat treated between 600 ° C - 1100 C °. The samples characterization was by thermogravimetry, X-ray diffraction and physical tests (water absorption, linear retraction and three points flection). The clays are composed mainly of kaolinite, illite-muscovite and quartz. The results showed that the Barro Preto clay showed better results in retraction, absorption and mechanical strain. (author)

  14. Mineral Acquisition from Clay by Budongo Forest Chimpanzees.

    Directory of Open Access Journals (Sweden)

    Vernon Reynolds

    Full Text Available Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay consumed indicates that it takes the form of kaolinite. We discuss the contribution of clay geophagy to the mineral intake of the Sonso chimpanzees and show that clay eaten using leaf sponges is particularly rich in minerals. We show that termite mound soil, also regularly consumed, is rich in minerals. We discuss the frequency of clay and termite soil geophagy in the context of the disappearance from Budongo Forest of a formerly rich source of minerals, the decaying pith of Raphia farinifera palms.

  15. Mineral Acquisition from Clay by Budongo Forest Chimpanzees.

    Science.gov (United States)

    Reynolds, Vernon; Lloyd, Andrew W; English, Christopher J; Lyons, Peter; Dodd, Howard; Hobaiter, Catherine; Newton-Fisher, Nicholas; Mullins, Caroline; Lamon, Noemie; Schel, Anne Marijke; Fallon, Brittany

    2015-01-01

    Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay consumed indicates that it takes the form of kaolinite. We discuss the contribution of clay geophagy to the mineral intake of the Sonso chimpanzees and show that clay eaten using leaf sponges is particularly rich in minerals. We show that termite mound soil, also regularly consumed, is rich in minerals. We discuss the frequency of clay and termite soil geophagy in the context of the disappearance from Budongo Forest of a formerly rich source of minerals, the decaying pith of Raphia farinifera palms.

  16. Mineralogical characterization of Greda clays and monitoring of their phase transformations on thermal treatment

    International Nuclear Information System (INIS)

    Chavez Panduro, E.; Bravo Cabrejos, J.

    2010-01-01

    The mineralogical characterization of two clay samples from the Central Andean Region of Peru, denominated White Greda and Red Greda, is reported. These clays contain the clay minerals mica and illite respectively. Both clays were treated thermally in an oxidising atmosphere under controlled conditions up to 1,100 deg. C with the purpose of obtaining information about structural changes that may be useful for pottery manufacture. X-ray fluorescence was used for the elemental characterization of the samples and X-ray diffractometry was used to determine the collapse and formation of the mineral phases present in the samples caused by thermal treatment. At temperatures above 1,000 deg. C it is observed the formation of spinel in the case of White Greda and of hematite, corundum and cristobalite in the case of Red Greda. Room temperature transmission Moessbauer spectroscopy allowed the monitoring of the variation of the hyperfine parameters with the thermal treatment temperature; In the case of the evolution of the quadruple splitting of the paramagnetic Fe 3+ sites with temperature, in both clays, the analyses reproduced results such as the 'camel back' curve shape, found by other workers (Wagner and Wagner, Hyperfine Interact 154:35-82, 2004; Wagner and Kyek, Hyperfine Interact 154:5-33, 2004).

  17. Mineralogical characterization of Greda clays and monitoring of their phase transformations on thermal treatment

    Science.gov (United States)

    Panduro, E. Chavez; Cabrejos, J. Bravo

    2010-01-01

    The mineralogical characterization of two clay samples from the Central Andean Region of Peru, denominated White Greda and Red Greda, is reported. These clays contain the clay minerals mica and illite respectively. Both clays were treated thermally in an oxidising atmosphere under controlled conditions up to 1,100°C with the purpose of obtaining information about structural changes that may be useful for pottery manufacture. X-ray fluorescence was used for the elemental characterization of the samples and X-ray diffractometry was used to determine the collapse and formation of the mineral phases present in the samples caused by thermal treatment. At temperatures above 1,000°C it is observed the formation of spinel in the case of White Greda and of hematite, corundum and cristobalite in the case of Red Greda. Room temperature transmission Mössbauer spectroscopy allowed the monitoring of the variation of the hyperfine parameters with the thermal treatment temperature; In the case of the evolution of the quadruple splitting of the paramagnetic Fe3 + sites with temperature, in both clays, the analyses reproduced results such as the “camel back” curve shape, found by other workers (Wagner and Wagner, Hyperfine Interact 154:35-82, 2004; Wagner and Kyek, Hyperfine Interact 154:5-33, 2004).

  18. Mineralogical characterization of Greda clays and monitoring of their phase transformations on thermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chavez Panduro, E., E-mail: 04130127@unmsm.edu.pe; Bravo Cabrejos, J., E-mail: jbravoc@unmsm.edu.pe [Universidad Nacional Mayor de San Marcos, Facultad de Ciencias Fisicas (Peru)

    2010-01-15

    The mineralogical characterization of two clay samples from the Central Andean Region of Peru, denominated White Greda and Red Greda, is reported. These clays contain the clay minerals mica and illite respectively. Both clays were treated thermally in an oxidising atmosphere under controlled conditions up to 1,100 deg. C with the purpose of obtaining information about structural changes that may be useful for pottery manufacture. X-ray fluorescence was used for the elemental characterization of the samples and X-ray diffractometry was used to determine the collapse and formation of the mineral phases present in the samples caused by thermal treatment. At temperatures above 1,000 deg. C it is observed the formation of spinel in the case of White Greda and of hematite, corundum and cristobalite in the case of Red Greda. Room temperature transmission Moessbauer spectroscopy allowed the monitoring of the variation of the hyperfine parameters with the thermal treatment temperature; In the case of the evolution of the quadruple splitting of the paramagnetic Fe{sup 3+} sites with temperature, in both clays, the analyses reproduced results such as the 'camel back' curve shape, found by other workers (Wagner and Wagner, Hyperfine Interact 154:35-82, 2004; Wagner and Kyek, Hyperfine Interact 154:5-33, 2004).

  19. Development of nanocomposites polyamide66/ bentonite clay membranes obtained by solution for water-oil separation

    International Nuclear Information System (INIS)

    Medeiros, Keila Machado de

    2010-01-01

    Microporous membranes were obtained from nanocomposites polyamide66 and regional bentonite clay, through the technique of immersion precipitation. The nanocomposites were obtained by solution with a pre-established reaction time. The clay was treated with quaternary ammonium salt (Cetremide®) in order to make it organophilic. Untreated and treated clay were characterized by X-ray fluorescence (XRF) spectroscopy, Fourier transform infrared (FTIR), X-ray diffraction (XRD) and thermogravimetry (TG), which confirmed the insertion of the Cetremide® salt in the layers of clay and their thermal stability. While the membranes were characterized by XRD, TG, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and flow measurements. The results of XRD, TG and DSC confirmed the thermal stability and morphological structure with intercalated/partially exfoliated lamellae of clay in the polymer matrix. By SEM, it was revealed an asymmetric morphology consisting of a skin layer and a porous sublayer. The higher clay content in the membrane give the lower film thickness. This influencing directly the flow measurements of the membranes produced from the nanocomposites. In general, the initial flow with distilled water through the membranes decrease and stabilise after 60 min, this due to a compression or swelling occurred in the membranes. In tests of water-oil separation it was found that the relationship J/J0 tends to be greater when using emulsions with lower concentration. The water-oil separation tests at concentrations of 300 and 500 ppm for all membranes showed a significant reduction in oil concentration in the permeate, thus showing that these membranes have potential for this application. (author)

  20. Behavior of clay exposed to heating

    International Nuclear Information System (INIS)

    Heremans, R.; Buyens, M.; Manfroy, P.

    1978-01-01

    In the frame of his R and D programme on geological burial of solidified radioactive waste, the C.E.N./S.C.K. undertook experimental and theoretical work on the behavior of the Boom clay against heat. The work is performed under contract with the Commission of European Communities. In a first phase a series of chemical and physical properties were determined on clay samples taken at various depths during the core boring performed on the C.E.N./S.C.K. site in 1975. In a second phase, a simulated high level waste heat source was developed and tested in view of representative heat transfer experiments into the geological formation. In parallel to the experimental work, computarized theoretical studies were undertaken aiming an evaluation of heat effect of a vitrified high level waste repository on an underground structure in clay

  1. Interaction of polymer with discotic clay particles

    International Nuclear Information System (INIS)

    Auvray, L.; Lal, J.

    1999-01-01

    Normally synthetic well defined monodisperse discotic laponite clays are known to form a gel phase at mass concentrations as low as a few percent in distilled water. Hydrosoluble polymer polyethylene oxide was added to this intriguing clay system, it was observed that it either prevents gelation or slows it down extremely depending on the polymer weight, concentration or the laponite concentration. Small Angle Neutron scattering (SANS) was used to study these systems because only by isotopic labeling can the structure of the adsorbed polymer layers be determined. The contrast variation technique is specifically used to determine separately the different partial structure factors of the clay and polymer. In this way the signal of the adsorbed chains is separated from the signal of the free chains in the dilute regime. Attempts have also been made to characterize the structure in the concentrated regime of laponite with polymer

  2. Preparation of organophilic clays and polypropylene nano composites

    International Nuclear Information System (INIS)

    Lima, Martha Fogliato S.; Nascimento, Vinicius G. do; Lenz, Denise M.; Schenato, Flavia

    2011-01-01

    Polypropylene/montmorillonite nano composites were prepared by the melt intercalation technique. The clay was organically modified with different quaternary ammonium salts to obtain the organo clay. The modified clays with the quaternary ammonium salts were introduced in a polypropylene matrix with 3 wt. % of clay. The interlayer distance (d001) of the clay particles were obtained by X- ray diffraction and the thermal stability of the systems were investigated by thermogravimetry. The organo clay presence in the polymer matrix increased the degradation temperature in relation to the pure polymer. (author)

  3. Removal of Phenol in Aqueous Solution Using Kaolin Mineral Clay

    International Nuclear Information System (INIS)

    Sayed, M.S.

    2008-01-01

    Kaolin clay were tested for phenol removal as toxic liquid waste from aqueous waste water. Several experimental conditions such as weight and particle size of clay were investigated to study batch kinetic techniques, also the ph and concentration of the phenol solution were carried out. The stability of the Langmuir adsorption model of the equilibrium data were studied for phenol sorbent clay system. Infrared spectra, thermogravimetric and differential thermal analysis techniques were used to characterize the behavior of kaolin clay and kaolin clay saturated with phenol. The results obtained showed that kaolin clay could be used successfully as an efficient sorbent material to remove phenol from aqueous solution

  4. Moessbauer firing study of Peruvian clays

    International Nuclear Information System (INIS)

    Salazar, R.; Wagner, U.; Wagner, F.E.

    1983-01-01

    In connection with work on ancient ceramics Moessbauer studies of the firing behaviour of six Peruvian clays have been performed in oxidizing and reducing atmospheres. For two clays, one of them is poor, the other one is rich in oxides, the change of the Moessbauer parameters on firing between 100 and 1350 0 C was measured in detail, both with and without preceding reduction. The minerals present at characteristic temperatures are determined by X-ray diffraction and an attempt is made to discuss the physical and chemical processes occurring in the different temperature ranges. (author)

  5. Synthetic clay excels in 90Sr removal

    International Nuclear Information System (INIS)

    Komarneni, Sridhar; Kodama, Tatsuya; Paulus, William J.; Carlson, C.

    2000-01-01

    Tests with actual ground water from Hanford site, and fundamental studies of 2Na + →Sr 2+ exchange equilibria revealed that a synthetic clay is extremely selective for 90 Sr with a high capacity for uptake. Comparative studies with existing Sr selective ion exchangers clearly revealed that the present synthetic clay exhibited the best performance for 90 Sr removal from actual ground water collected from three different locations at Hanford. This novel Sr ion sieve is expected to be useful for the decontamination of the environment after accidental release and contamination with 90 Sr. (c) 2000 Materials Research Society

  6. Quick clay and landslides of clayey soils.

    Science.gov (United States)

    Khaldoun, Asmae; Moller, Peder; Fall, Abdoulaye; Wegdam, Gerard; De Leeuw, Bert; Méheust, Yves; Otto Fossum, Jon; Bonn, Daniel

    2009-10-30

    We study the rheology of quick clay, an unstable soil responsible for many landslides. We show that above a critical stress the material starts flowing abruptly with a very large viscosity decrease caused by the flow. This leads to avalanche behavior that accounts for the instability of quick clay soils. Reproducing landslides on a small scale in the laboratory shows that an additional factor that determines the violence of the slides is the inhomogeneity of the flow. We propose a simple yield stress model capable of reproducing the laboratory landslide data, allowing us to relate landslides to the measured rheology.

  7. Effects of Different Types of Clays and Maleic Anhydride Modified Polystyrene on Polystyrene/Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    M. Mehrabzadeh

    2013-01-01

    Full Text Available Polymer/clay nanocomposites are considered as a new subject of research in Iran and the world. Addition of a minimum amount of clay (2-5wt% can improve the mechanical properties, enhance barrier properties and reduce flammability dramatically. Polystyrene (PS exhibits high strength, high modulus and excellent dimensional stability, but it has poor ductility, elongation, and flexural modulus. By incorporating clay into polystyrene these properties can be improved. In this study preparation of polystyrene/clay nanocomposite, effects of different types of clays (Cloisite 10A andNanomer I.30TC and maleic anhydride modified polystyrene on mechanical properties of the prepared polystyrene/clay nanocomposites were evaluated. Samples were prepared by a twin screw extruder. Transmission electron microscopy (TEM and X-ray diffraction (XRD techniques were employed to evaluate the extent of intercalation and exfoliation of silicate layers in the nanocomposites. Mechanical tests show that by addition of clay and maleic anhydride modified polystyrene the flexural modulus (~30% and elongation-at-break (~40% of prepared nanocomposites have been improved. XRD and TEM results show that nanocomposite have an intercalated structure with ability to change to further exfoliation structure.

  8. Clay intercalation and influence on crystallinity of EVA-based clay nanocomposites

    International Nuclear Information System (INIS)

    Chaudhary, D.S.; Prasad, R.; Gupta, R.K.; Bhattacharya, S.N.

    2005-01-01

    Various polymer clay nanocomposites (PCNs) were prepared from ethylene vinyl acetate copolymer (EVA) with 9, 18 and 28% vinyl acetate (VA) content filled with different wt.% (2.5, 5 and 7.5) of a Montmorillonite-based organo-modified clay (Cloisite[reg] C15A and C30B). The PCNs were prepared using melt blending techniques. Morphological information regarding intercalation and exfoliation were determined by using wide-angle X-ray scattering (WAXS) and transmission electron microscopy (TEM). WAXS and TEM confirmed that increasing the VA content was necessary to achieve greater clay-polymer interaction as seen from the comparatively higher intercalation of clay platelets with 28% VA. The effect of addition of clay on the development and the modification of crystalline morphology in EVA matrix was also studied using WAXS and temperature-modulated differential scanning calorimetry (MDSC). Results are presented showing that the addition of clay platelets does not increase the matrix crystallinity but the morphology was significantly modified such that there was an increase in the 'rigid' amorphous phase. Mechanical properties were also evaluated against the respective morphological information for each specimen and there are indications that the level of clay-polymer interaction plays a significant role in such morphological modification, and in such a way that affects the final PCN mechanical properties which has wide and significant applications in the packaging industries

  9. Geotechnical characterization of mined clay from Appalachian Ohio: challenges and implications for the clay mining industry.

    Science.gov (United States)

    Moran, Anthony R; Hettiarachchi, Hiroshan

    2011-07-01

    Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling.

  10. Optimization of organo clay production for applications in based oil drilling fluid; Otimizacao do processo de organofilizacao para aplicacoes em fluidos de perfuracao base oleo

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Heber S.; Martins, Alice B.; Costa, Danubia L. da; Ferreira, Heber C.; Neves, Gelmires de A.; Melo, Tomas J.A. de [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Teixeira Neto, Erico [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

    2008-07-01

    The organophilic clays are widely used as an agent dispersed in the composition of oil based drilling fluids. The organophilic clays are gotten from bentonite clays treated, in watery way, with ionic surfactants, that are adsorbed in the surface of interlayer of the clays, re-covered them with a organic layer. A fundamental stage of production of the organophilic clays is the dispersion of bentonite clays, in way that variables like: speed of agitation, temperature and time of cure, influences directly in plastic and apparent viscosities of these dispersions, together with other variables of organophilization process, like, temperature and time of cure of organophilization, has direct influence in efficiency of the organophilization process. This work considers a study of these variable, using bentonite clays: Brasgel PA{sup R} and Cloisite Na{sup +R}, treated with the ionic surfactant Praepagem WB{sup R}. The organophilic clays gotten had been characterized by rays X diffraction, Foster's swelling, and the results were compared with the commercial organophilic clay VG-69{sup R}, industrially treated with ionic surfactant. Viscosities plastic and apparent of the dispersions had been measured in the midst of organic dispersant diesel oil used to obtain the oil based drilling fluids. Preliminary results of Foster's swelling and preparation of fluids show that the clays have affinity with the means liquid organic dispersants, and the fluids meet specifications of PETROBRAS (N-22581-1997 and N-2259 to 1997) for use in the of diesel oil based drilling fluids. (author)

  11. Multiscale Micromechanical Modeling of Polymer/Clay Nanocomposites and the Effective Clay Particle

    Science.gov (United States)

    Sheng, Nuo; Boyce, Mary C.; Parks, David M.; Manovitch, Oleg; Rutledge, Gregory C.; Lee, Hojun; McKinley, Gareth H.

    2003-03-01

    Polymer/clay nanocomposites have been observed to exhibit enhanced mechanical properties at low weight fractions (Wp) of clay. Continuum-based composite modeling reveals that the enhanced properties are strongly dependent on particular features of the second-phase ¡°particles¡+/-; in particular, the particle volume fraction (fp), the particle aspect ratio (L/t), and the ratio of particle mechanical properties to those of the matrix. However, these important aspects of as-processed nanoclay composites have yet to be consistently and accurately defined. A multiscale modeling strategy was developed to account for the hierarchical morphology of the nanocomposite: at a lengthscale of thousands of microns, the structure is one of high aspect ratio particles within a matrix; at the lengthscale of microns, the clay particle structure is either (a) exfoliated clay sheets of nanometer level thickness or (b) stacks of parallel clay sheets separated from one another by interlayer galleries of nanometer level height. Here, quantitative structural parameters extracted from XRD patterns and TEM micrographs are used to determine geometric features of the as-processed clay ¡°particles¡+/-, including L/t and the ratio of fp to Wp. These geometric features, together with estimates of silicate lamina stiffness obtained from molecular dynamics simulations, provide a basis for modeling effective mechanical properties of the clay particle. The structure-based predictions of the macroscopic elastic modulus of the nanocomposite as a function of clay weight fraction are in excellent agreement with experimental data. The adopted methodology offers promise for study of related properties in polymer/clay nanocomposites.

  12. Mineralogy and geotechnical characteristics of some pottery clay

    Directory of Open Access Journals (Sweden)

    Mujib Olamide ADEAGBO

    2016-12-01

    Full Text Available The physical properties of soils, which are tremendously influenced by the active clay minerals in soil, are of great importance in geotechnical engineering. This paper investigates the clay-sized particles of the Igbara-Odo pottery clay, and compares results obtained with available data on the bulk sample, to determine their correlation and underline the dependence of the geotechnical properties of the bulk clay material on the clay-sized particles. The bulk clay sample consists of 52% sand-size particles, 21% silt and 27% clay. Analysis of the clay-sized particles and the bulk materials shows: specific gravity of 2.07 and 2.66, liquid limit of 91.0% and 33.0%, plastic limit of 27.5% and 14.3%, plasticity index of 63.5% and 18.7% and a linear shrinkage of 7.9% and 5.4%, for both clay-sized particles and bulk clay respectively. The activity value of the clay material (0.64 suggests the presence of Kaolinite and Ilite; and these were confirmed with X-Ray diffraction on the bulk sample and clay-sized particles. X-Ray diffraction patterns shows distinctive peaks which highlight the dominance of Kaolinite (with 8 peaks in the pottery clay sample for both clay-sized particles and bulk material; while traces of other clay minerals like Illite and Halloysite and rock minerals like Mica, Feldspar and Chrysotile were also found. These results suggest that the clay possesses high viability in the manufacturing of ceramics, refractory bricks, paper, fertilizer and paint. The clay material can be used as a subgrade in road construction, since it possesses low swelling characteristics.

  13. Preparation of nanocomposites polyurethane water bone with clay montmorillonite sodica and organophilic clay

    International Nuclear Information System (INIS)

    Garcia, Claudia P.; Delpech, Marcia C.; Coutinho, Fernanda M.B.; Mello, Ivana L.

    2009-01-01

    Nanocomposites based on water bone polyurethane (NWPU's) were synthesized based on poli(propylene glycol), dimethylolpropionic acid (DMPA), isophorone diisocyanate (IPDI) and hydrazine (HYD), as chain extender. Two kinds of clays were employed: hydrophilic and organophilic. The nanocomposites were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electronic microscopy (SEM) and the mechanical properties were evaluated. The FTIR results showed the presence of specific groups of clay and the XRD suggested that occurred their intercalation/exfoliation through polyurethane matrix. The mechanical resistance of the systems showed significant increase when compared to water dispersions synthesized without clay. (author)

  14. Crystallite size distribution of clay minerals from selected Serbian clay deposits

    Directory of Open Access Journals (Sweden)

    Simić Vladimir

    2006-01-01

    Full Text Available The BWA (Bertaut-Warren-Averbach technique for the measurement of the mean crystallite thickness and thickness distributions of phyllosilicates was applied to a set of kaolin and bentonite minerals. Six samples of kaolinitic clays, one sample of halloysite, and five bentonite samples from selected Serbian deposits were analyzed. These clays are of sedimentary volcano-sedimentary (diagenetic, and hydrothermal origin. Two different types of shape of thickness distribution were found - lognormal, typical for bentonite and halloysite, and polymodal, typical for kaolinite. The mean crystallite thickness (T BWA seams to be influenced by the genetic type of the clay sample.

  15. Feasibility of using overburden clays for sealing purposes and laboratory testing of the clays

    Energy Technology Data Exchange (ETDEWEB)

    Mann, J. (Vyzkumny Ustav pro Hnede Uhli, Most (Czechoslovakia))

    1992-03-01

    Studies properties of overburden clay from North Bohemian surface coal mines for use as sealants of industrial and household waste that will be dumped at Czechoslovak surface mine sites. Basic requirements of sealing layers are optimum compressibility and impermeability by suitable compacting. Laboratory soil mechanical tests of different clay samples were carried out using the Proctor standard tests (PCS) and the Norwegian Geonor A/S - m 45 instrument. Laboratory tests were used to select the best available clay types with optimum density and moisture content. Experimental results of laboratory tests are provided.

  16. Xenon-129 NMR study of the microporous structure of clays and pillared clays

    International Nuclear Information System (INIS)

    Tsiao, C.; Carrado, K.A.

    1990-01-01

    129 Xe NMR studies have been carried out using xenon gas adsorbed in clays and pillared clays. Data from the measurements provide information on the pore structure of clays before and after pillaring. The results indicate that the effective pore diameter of montmorillonite increases, for example, from 5.4 Angstrom to 8.0 Angstrom after pillaring cheto-montmorillonite with aluminum polyoxohydroxy Keggin cations. The data are consistent with X-ray powder diffraction results, which show a corresponding increase in the interlamellar gallery height from 5.6 Angstrom to 8.4 Angstrom

  17. Stabilization of an expansive overconsolidated clay using hydraulic binders

    Directory of Open Access Journals (Sweden)

    Abdelkrim Mahamedi

    2015-04-01

    Full Text Available Urban areas of the wilaya of M’sila in Algeria nowadays experience a considerable development because of an unceasingly increasing demography, from where its extension toward virgin zones is often less favorable than those already urbanized. This wilaya is located in a zone classified as semi-arid, whose geology comprises clayey formations characterized by a high variation of volume when the conditions of their equilibrium are modified (natural climatic phenomena due to a prolonged dryness, human activity by modification of the ground water level because of excessive pumping, configuration of constructions in their environment. This paper presents and analyzes the results of a series of laboratory tests (identification, compaction, penetration and direct shear tests performed on an expansive overconsolidated clay obtained from an urban site situated in Sidi-Hadjrès city (wilaya of M’sila, Algeria, where significant damages frequently appear in the road infrastructures and in the light structures. Test results obtained show that the geotechnical parameteric values deduced from these tests are concordant and confirm the bearing capacity improvement of this natural clay treated with hydraulic binders (composed Portland cement and extinct lime and compacted under the optimum Proctor conditions, which is translated by a significant increase in soil strength and its durability.

  18. Preparation of Synthetic Zeolites from Myanmar Clay Mineral

    International Nuclear Information System (INIS)

    Phyu Phyu Win

    2004-04-01

    Faujasite type zeolite X was successfully synthesized from Myanmar clay mineral kaolinite, by treating with sodium hydroxide at 820 C followed by dissolution in water and hydrothermal treatment. It was found that the solution of fused clay powder can be crystallized at 90C under ambient pressure to synthesize faujasite type zeolite X. The effects of aging time and the amount of water on the formation of the product phase and Si/ Al ratios of the resulting products were investigated. Most of the Si and Al components in kaolinite might be dissolved into an alkaline solution and reacted to form ring-like structures. Then it was effectively transformed into zeolite materials. The maximum relative crystallinity of faujasite zeolite obtained was found to be 100%. Zeolite P was found to be a competitive phase present in some resulting products during hydrothermal treatment. The cation exchange capacity of kaolinite is very low, but increased after a proper treatment. It was found that the prepared faujasite type zeolite X, zeolite P and hydrogen zeolite (HZ) can reduce the hardness, the alkalinity, the total dissolved solid and the dissolved iron of raw water in the batch wise operation of water treatment. Therefore, it can be used as the cation exchanged resin for water treatment

  19. Ion Exchange Resin and Clay Vitrification by Plasma Discharges

    International Nuclear Information System (INIS)

    Diaz A, Laura V.; Pacheco S, Joel O.; Pacheco P, Marquidia; Monroy G, Fabiola; Emeterio H, Miguel; Ramos F, Fidel

    2006-01-01

    The lack of treatment of a low and intermediate level radioactive waste (LILRW) lead us to propose a vitrification process based on a plasma discharge; this technique incorporates LILRW into a matrix glass composed of ceramic clays material. The Mexican Institute of Nuclear Research (ININ), uses an ion exchange resin IRN 150 (styrene-divinilbence copolymer) in the TRIGA MARK III nuclear reactor. The principal objective of this resin is to absorb particles containing heavy metals and low-level radioactive particles. Once the IRN 150 resin filter capacity has been exceeded, it should be replaced and treated as LILRW. In this work, a transferred plasma system was realized to vitrify this resin taking advantage of its high power density, enthalpy and chemical reactivity as well as its rapid quenching and high operation temperatures. In order to characterize the morphological structure of these clay samples, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Thermogravimetric analysis (TGA) techniques were applied before and after the plasma treatment

  20. Semi-industrial production of organo clays to use in base oil drilling fluid; Producao em escala piloto de argilas organofilicas visando uso em fluidos de perfuracao base oleo

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Heber S.; Martins, Alice B.; Costa, Danubia L. da; Ferreira, Heber C.; Neves, Gelmires de A.; Melo, Tomas J.A. de [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Teixeira Neto, Erico [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

    2008-07-01

    The drilling fluids are essential to the operations of exploration of oil. The organoclays are widely used in the composition of the oil based drilling fluids and raw materials are of high value added. These clays can be obtained, traditionally, from bentonitic clay treated, in water, with ionic surfactants, however, non-ionic surfactants can be adsorbed on the surface of interlamelar bentonitic clay, naturally hydrophilic, making them organophilic. A pilot plant for production of organoclays was mounted in the Recycling Laboratory / UFCG. The bentonitic clay imported Cloisite Na{sup +R} was treated with a non-ionic surfactant in levels of 40, 50 and 60% in scale and bench-scale pilot. The commercial organoclay VG-69{sup R} was used as a standard for comparison of results. The clay obtained were characterized by X-ray diffraction, and Foster's swelling. The oil based fluids were prepared in accordance with the standards of PETROBRAS (N-22581 1997 and N-2259, 1997). Tests show that the characterization of organoclays have obtained intercalation of non-ionic surfactant with great expansion of layers of clay, with interlayer distances more significant than the clay trade, both on clay obtained in the laboratory scale as in clays obtained by pilot scale, with results very similar for both methods. It appears that it is possible the pilot-scale production of organoclays with equivalent quality produced in the laboratory scale and quality compatible with the clay used commercially. (author)

  1. Organophilic clays as a tracer to determine Erosion processes

    Science.gov (United States)

    Mentler, A.; Strauss, P.; Schomakers, J.; Hann, S.; Köllensberger, G.; Ottner, F.

    2009-04-01

    In recent years the use of new tracing techniques to measure soil erosion has gained attention. Beside long time existing isotopic methods the use of rare earth elements has been reported. We wanted to contribute to the efforts of obtaining better methods for determination surface soil movement and tested a novel method using organophilic clays as a tracer for erosion related studies. At present tests to extract organophilic clays from soil have been performed successfully using an Industrial produced organophilic bentonite (Tixogel TVZ, Süd-Chemie) treated with quaternary ammonium surfactants. A liquid extraction method with barium ions (Ba2+) and methanol was used to extract the n-alkyl ammonium compounds from the inter crystal layers of the modified Bentonite. To increase extraction efficiency, an ultrasound device was used (UW 2200 Bandelin, 10.000 cycles per second, vibration amplitude 54 µm, sonification time of one minute). This procedure lead to a recovery rate of about 85% for the organophilic bentonite. This was clearly superior to alternative extraction methods such as acetonitrile in different mixing ratios. Quantification of the extracted surfactants was performed via high performance liquid chromatography - mass spectrometry (HPLC-MS, Agilent 1200 SL HPLC and 6220 time-of-flight MS). The mass spectra of this industrial produced organophilic clay mineral showed four different molecular masses (M+H+ of 304.30, 332.33, 360.36 and 388.39. The four substances could be separated by HPLC (20 x 2 mm Zorbax C18 reversed phase column, 0.5 mL/min isocratic flow with 90% acetonitrile and 0.1% formic acid in water, run time of 7 minutes). The linear working range of the method was 5 to 1000 µg/L, with a limit of quantification of 1 µg/L n-alkyl ammonium compound. All four compounds of the Tixogel were extracted with identical extraction efficiencies and are hence suitable for accurate quantification procedures. Next steps of the methodology to develop are the

  2. Ice nucleation efficiency of clay minerals in the immersion mode

    Directory of Open Access Journals (Sweden)

    V. Pinti

    2012-07-01

    Full Text Available Emulsion and bulk freezing experiments were performed to investigate immersion ice nucleation on clay minerals in pure water, using various kaolinites, montmorillonites, illites as well as natural dust from the Hoggar Mountains in the Saharan region. Differential scanning calorimeter measurements were performed on three different kaolinites (KGa-1b, KGa-2 and K-SA, two illites (Illite NX and Illite SE and four natural and acid-treated montmorillonites (SWy-2, STx-1b, KSF and K-10. The emulsion experiments provide information on the average freezing behaviour characterized by the average nucleation sites. These experiments revealed one to sometimes two distinct heterogeneous freezing peaks, which suggest the presence of a low number of qualitatively distinct average nucleation site classes. We refer to the peak at the lowest temperature as "standard peak" and to the one occurring in only some clay mineral types at higher temperatures as "special peak". Conversely, freezing in bulk samples is not initiated by the average nucleation sites, but by a very low number of "best sites". The kaolinites and montmorillonites showed quite narrow standard peaks with onset temperatures 238 K<Tonstd<242 K and best sites with averaged median freezing temperature Tmedbest=257 K, but only some featuring a special peak (i.e. KSF, K-10, K-SA and SWy-2 with freezing onsets in the range 240–248 K. The illites showed broad standard peaks with freezing onsets at 244 K Tonstd<246 K and best sites with averaged median freezing temperature Tmedbest=262 K. The large difference between freezing temperatures of standard and best sites shows that characterizing ice nucleation efficiencies of dust particles on the basis of freezing onset temperatures from bulk experiments, as has been done in some atmospheric studies, is not appropriate. Our investigations

  3. Quantitative approach on SEM images of microstructure of clay soils

    Institute of Scientific and Technical Information of China (English)

    施斌; 李生林; M.Tolkachev

    1995-01-01

    The working principles of Videolab Image Processing System (VIPS), the examining methods of orientation of microstructural units of clay soils and analysing results on SEM images of some typical microstructures of clay soils using the VIPS are introduced.

  4. Hydration Phase Diagram of Clay Particles from Molecular Simulations.

    Science.gov (United States)

    Honorio, Tulio; Brochard, Laurent; Vandamme, Matthieu

    2017-11-07

    Adsorption plays a fundamental role in the behavior of clays. Because of the confinement between solid clay layers on the nanoscale, adsorbed water is structured in layers, which can occupy a specific volume. The transition between these states is intimately related to key features of clay thermo-hydro-mechanical behavior. In this article, we consider the hydration states of clays as phases and the transition between these states as phase changes. The thermodynamic formulation supporting this idea is presented. Then, the results from grand canonical Monte Carlo simulations of sodium montmorillonite are used to derive hydration phase diagrams. The stability analysis presented here explains the coexistence of different hydration states at clay particle scale and improves our understanding of the irreversibilities of clay thermo-hydro-mechanical behavior. Our results provide insights into the mechanics of the elementary constituents of clays, which is crucial for a better understanding of the macroscopic behavior of clay-rich rocks and soils.

  5. Radionuclide transport in clay during climate change

    NARCIS (Netherlands)

    Wildenborg, A.F.B.; Orlic, B.; Thimus, J.F.; De Lange, G.; De Cock, S.; De Leeuwe, C.S.; Veling, E.J.M.

    2002-01-01

    The Dutch national research programme into the feasibility of retrievable storage of radioactive waste (CORA Programme Phase I; CORA: Comité Opslag Radioactief Afval = Committee on Radioactive Waste Disposal) examined the suitability of Tertiary clay deposits for such storage. Long-term isolation –

  6. Radionuclide transport in clay during climate change

    NARCIS (Netherlands)

    Wildenborg, A.F.B.; Orlic, B.; Thimus, J.F.; Lange, G.de; Cock, S. de; Leeuw, C.S. de; Veling, E.J.M.

    2003-01-01

    The Dutch national research programme into the feasibility of retrievable storage of radioactive waste (CORA Programme Phase I; CORA: Comité Opslag Radioactief Afval = Committee on Radioactive Waste Disposal) examined the suitability of Tertiary clay deposts for such storage. Long-term isolation -

  7. On the thermal behaviour of Boom clay

    International Nuclear Information System (INIS)

    Delage, P.; Cui Yu Jun; Sultan, N.

    2004-01-01

    When temperature is increased, the various phenomena that occur in a saturated natural potential host clay for nuclear waste disposal (Boom clay from SCK-CEN in Mol, Belgium) were experimentally investigated in a temperature controlled high stress triaxial cell. Firstly, the pore pressure build-up due to the difference in thermal dilation of both water and minerals was investigated through thermal consolidation tests. Interesting information was obtained about the dissipation of thermally induced pore pressure in Boom clay, based on the standard Terzaghi consolidation theory. Secondly, the volume change behaviour in drained conditions (i.e. under a very slow temperature increase) confirmed that the clay overconsolidation ratio (OCR) controlled the nature of the volume changes. Whereas overconsolidated soils use to dilate as any material when temperature is elevated, normally consolidated soils present a decrease in volume, which is less common. The principles of a coupled thermo-elasto-plastic model that was specifically developed to model this particular behaviour are finally presented. Obviously, it appears necessary to account in detail for these thermal phenomena in order to properly understand the response of the geological barrier in the near field once nuclear waste has been stored. (orig.)

  8. Heap leaching of clay ish uranium ores

    International Nuclear Information System (INIS)

    Gonzalez, E.; Sedano, A.

    1973-01-01

    This paper describes an experimental facility, built near El Lobo mine. In it we study the beneficiation of low-grade uranium ore. The mineral has a great amount of clay and fines. The flow-sheet used has four steps: head leaching, ph-ajustement, ion-exchange and participation. We show, also, the most interesting results. (Author)

  9. Calm, Cool, and Comfortable in Clay

    Science.gov (United States)

    Stylianou, Xanthippi Cynthia

    2010-01-01

    The author's fourth-grade students had just finished a drawing unit that focused on the human figure. Projects included charcoal gesture drawings and chalk manikin drawings in chiaroscuro. She wanted to integrate a new medium for students to continue their study of the human figure. Since students are always excited to work with clay, making clay…

  10. Classroom Instruction: The Influences of Marie Clay

    Science.gov (United States)

    McNaughton, Stuart

    2014-01-01

    Marie Clay's body of work has influenced classroom instruction in direct and indirect ways, through large overarching themes in our pedagogical content knowledge as well as specific smart practices. This paper focuses on her the contributions to our thinking about instruction which come from two broad theoretical concepts; emergent literacy…

  11. Diffusion in Clay Layers and Groundwater Remediation

    Science.gov (United States)

    In a collaborative SERDP-funded study, researchers from the Air Force Institute of Technology, the U.S. Environmental Protection Agency, and the University of Michigan developed a numerical model that simulates the enhanced transport of CAHs into and out of low permeability clay ...

  12. Clay Shirky, Internet e il collegio invisibile

    Directory of Open Access Journals (Sweden)

    Maria Chiara Pievatolo

    2011-10-01

    Full Text Available Come Internet sta cambiando il nostro modo di pensare? Fra le 172 risposte presentate da Edge, Clay Shirky ne propone una particolarmente interessante per i ricercatori di professione. Internet, scrive Shirky, ha aumentato straordinariamente la capacità espressiva dell’umanità. Ma che una risorsa divenga abbondante, da scarsa che era, è una sfortuna, almeno per chi su [...

  13. Mineralogical and Geochemical Characterization of Clay and ...

    African Journals Online (AJOL)

    Bheema

    which include soil horizons, continental and marine sediments, geothermal fields, volcanic ... water, air, or steam and the type of clay however is controlled by the composition of pre-existing ... the lake basin is characterized by biannual nature of precipitation with a mean annual ...... isotope record from LakeAshenge.

  14. Clay Corner: Recreating Chinese Bronze Vessels.

    Science.gov (United States)

    Gamble, Harriet

    1998-01-01

    Presents a lesson where students make faux Chinese bronze vessels through slab or coil clay construction after they learn about the history, function, and design of these vessels. Utilizes a variety of glaze finishes in order to give the vessels an aged look. Gives detailed guidelines for creating the vessels. (CMK)

  15. Transport of Organic Solutes in Clay Formations

    Science.gov (United States)

    The research is a pilot investigation for the SERDP (Strategic Environmental Research and Development Program, DoD) founded project, Impact of Clay-DNAPL Interactions on Transport and Storage of Chlorinated Solvents in Low Permeability Zones, from 2010-2012. The report tries to s...

  16. Thermal stability of PMMA–clay hybrids

    Indian Academy of Sciences (India)

    Administrator

    Thermal stability of PMMA–clay hybrids. TANUSHREE CHOUDHURY* and NIRENDRA M MISRA. Department of Applied Chemistry, Indian School of Mines University, Dhanbad 826 004, India. MS received 9 December 2008. Abstract. Materials with small particle size are being extensively used in composites and hybrid ...

  17. Laboratory study of the Flandres clay swelling

    International Nuclear Information System (INIS)

    Khaddaj, Said

    1992-01-01

    The first chapter contains a survey about the swelling of soils, and about the experimental methods used to characterize this phenomenon. A classification of soils in function of their swelling potential is proposed. The second chapter deals with the properties of Flandres clay. Chemical and mineralogical compositions, mechanical properties and free swell index are given. The third chapter contains a presentation of the study of the swelling potential of Flandres clay using the oedometer. Four methods are described and used (free-swell, different pressures, pre-swell and direct-swell). A numerical simulation of free-swell tests is also given. The fourth chapter includes a presentation of the study of the swelling behaviour of Flandres clay using a triaxial cell. Three methods are used: free-swell, pre-swell and different-pressures. The last chapter contains a parametric study of the swelling behaviour of Flandres clay. The influence of some parameters such as sample thickness, initial water content, vertical load and load history is presented. (author) [fr

  18. Geotechnical studies of Jaitapur marine clay

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat, S.T.; Nayak, B.U.

    characterisEd. by high water content and high Atterberg limits. Undrained shear strength varied from 1.8 to 6 KPa. These were moderately sensitive clays. Carbonate content which varied from 3 to 27%, was found to influence engineering properties of the soil...

  19. Production of smectite organophylic clays from three commercial sodium bentonite

    International Nuclear Information System (INIS)

    Valenzuela Diaz, Francisco R.; Souza Santos, Persio de

    1995-01-01

    Laboratory cationic exchange procedures using Brazilian's commercial quaternary ammonium salt and three samples of commercial sodium bentonites (two Brazilian's and one from Wyoming (US) are described. Swelling values in some liquid organic media are shown for the organophilic clays and for a Brazilian's commercial organophilic clay. Organophilic clays with larger swelling values than the commercial organophilic clay in kerosene, Varsol, toluene and soya bean oil were obtained. (author)

  20. Treating hydrocarbon oils

    Energy Technology Data Exchange (ETDEWEB)

    Scott, R; MacIvor, W

    1869-09-01

    The treatment of hydrocarbon oils, such as coal or shale oils, paraffin oils, and petroleum, either in the crude or more or less refined state has the object of reducing the specific gravity and otherwise improving the qualities of such oils. The oil to be treated is put into any ordinary still and distilled. The vapor escaping during the distillation is passed through one or more heating vessels or chambers and exposed to the heat necessary to produce the change. The heating vessels or chambers may be made of metal, clay, or any other material adapted to endure heat, and they may be made of any desired form, or they may be constituted of a coil of metal pipes or a series of tubes such as are used for heating air for blast furnaces.

  1. Repository tunnel construction in deep clay formations

    International Nuclear Information System (INIS)

    Clarke, B.G.; Mair, R.J.; Taylor, R.N.

    1992-01-01

    One of the objects of the Hades project at Mol, Belgium has been to evaluate the feasibility of construction of a deep repository in the Boom clay formation at depth of approximately 225 metres. The main objective of the present project was to analyse and interpret the detailed geotechnical measurements made around the Hades trial shaft and tunnel excavations and evaluate the safety of radioactive waste disposal in a repository facility in deep clay formations. Plasticity calculations and finite element analyses were used which gave results consistent with the in-situ measurements. It was shown that effective stress analysis could successfully predict the observed field behaviour. Correct modelling of the small-strain stiffness of the Boom clay was essential if reasonable predictions of the pore pressure response due to construction are to be made. The calculations undertaken indicated that, even in the long term, the pressures on the test drift tunnel lining are likely to be significantly lower than the overburden pressure. Larger long-term tunnel lining pressures are predicted for impermeable linings. A series of laboratory stress path tests was undertaken to determine the strength and stiffness characteristics of the Boom clay. The tests were conducted at appropriate effective stress levels on high-quality samples retrieved during construction of the test drift. The apparatus developed for the testing is described and the results discussed. The development of a self boring retracting pressure-meter is described. This novel in-situ testing device was specifically designed to determine from direct measurements the convergence/confinement curve relevant to tunnelling in clay formations. 44 refs., 60 figs., 3 tabs

  2. Faults in clays their detection and properties

    International Nuclear Information System (INIS)

    Baldi, G.; Carabelli, E.; Chiantore, V.; Colombo, P.F.; Gruszka, A.; Pensieri, R.; Superbo, S.; Gera, F.

    1991-01-01

    The 'Faults in clays project', a cooperative research effort between Ismes and Enea of Italy and BGS and Exeter University of the UK, has been aimed at assessing and improving the resolution capability of some high resolution geophysical techniques for the detection of discontinuities in clay formations. All Ismes activities have been carried out in Italy: they consisted in the search of one or more sites - faulted clay formations - suitable for the execution of geophysical and geotechnical investigations, in the execution of such tests and in additional geological surveys and laboratory (geotechnical and geochemical) testing. The selected sites were two quarries in plio-pleistocenic clay formations in central Italy where faults had been observed. The greatest part of the research work has been carried out in the Orte site where also two 90 m boreholes have been drilled and cored. Geophysical work at Orte consisted of vertical electrical soundings (VESs) and horizontal electrical lines (HELs), four high resolution seismic reflection lines, and in-hole and cross-hole logs. Laboratory activities were geotechnical characterization and permeability tests, and measurements of disequilibrium in the uranium decay series. At Narni, where Exeter University sampled soil gases for geochemical analyses, the geophysical work consisted in a geo-electrical survey (five VESs and two HELs), and in two high resolution reflection seismic lines. Additional investigations included a structural geology survey. The main conclusion of the research is that current geophysical techniques do not have a resolution capacity sufficient to detect the existence and determine the characteristics of faults in deep homogeneous clay formations

  3. Water-clay interactions. Experimental study

    International Nuclear Information System (INIS)

    Gaucher, Eric

    1998-01-01

    Clay minerals contribute to the chemical composition of soil and sediment groundwaters via surface and dissolution/precipitation reactions. The understanding of those processes is still today fragmentary. In this context, our experimental purpose is to identify the contribution of each reaction in the chemical composition of water in a water/clay System. Kaolinite, illite, montmorillonite are the reference clays. After a fine mineralogical study, the exchange equilibria between K + and H + are characterised. Different exchange sites are identified and the exchange capacities and selectivity coefficients are quantified. Then, mixtures of the three clays are equilibrated with acidic and basic (I≤10 -2 M) solutions at 25 deg. C, 60 deg. C, 80 deg. C, during 320 days. The System evolution is observed by chemical analysis of the solutions and mineralogical analysis by TEM. We show that montmorillonite is unstable compared to the kaolinite/amorphous silica assemblage for solutions of pH<7. Aqueous silica is probably controlled by the kinetics of dissolution of the montmorillonite in moderate pH media. In more acidic solutions, amorphous silica precipitates. Al is under control of 'kaolinite' neo-formations. The use of the selectivity coefficients in a numerical simulation shows that K + concentration depends on exchange reactions. The pH has a more complicated evolution, which is not completely understood. This evolution depends on both exchange equilibria and organic acid occurrence. In this type of experiments, we have demonstrated that the equilibrium equations between smectite and kaolinite are inexact. The problem of the thermodynamic nature of clays remains and is not resolved by these solubility experiments. (author) [fr

  4. Migration of leachate solution through clay soil

    Energy Technology Data Exchange (ETDEWEB)

    Abdel Warith, M M

    1987-01-01

    The problem of domestic solid wastes buried in landfill sites is viewed from the aspect of leachate contamination and migration in the substrate, and the efficiency of natural clay barriers as an expedient economic lining material is assessed. Various chemical constituents of the landfill leachate of an actual waste containment site at Lachenaie (35 km east of Montreal) were determined from samples collected from specially designed basins. Data for companion tests on laboratory columns are also presented. Chemical analysis on samples from the basins and leachates from the columns measured changes in the concentration of: (a) cations (Na, K, Ca, and Mg), (b) anions (Cl, HCO/sub 3/, and CO/sub 3/) (c) total organic carbon (TOC), and (d) heavy metals (Fe, Zn, Pb, and Cu). The physical parameters measured included: (a) pH, and (b) specific conductivity. Predictions, using a dispersion-convection model for concentration profile development for either adsorbed or retained contaminants, were compared with the experimentally determined profiles (both in leaching columns and landfill laboratory model). Another set of experiments was also conducted to evaluate the effect of some organic fluids on the geotechnical properties of different clay soils (natural clay and two reference clay soils: illite and kaolinite). The results from this study have demonstrated that the natural clay soil can be used to adequately contain the different contaminant species usually present in the leachate solutions. Furthermore, the data suggested that under favorable soil conditions, landfill leachates containing low levels of trace metals will not pose a substantial contamination threat to the subsurface environment, provided that a proper thickness of barrier is used.

  5. Characterization of two clays - attapulgite and sepiolite - before and after acid activation; Caracterizacao de duas argilas - atapulgita e sepiolita - antes e apos ativacao acida com HCl

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, R.N.; Soares, G.A., E-mail: renataoliveira@poli.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Centro de Tecnologia; Barreto, L.S. [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil)

    2009-07-01

    Among the special clays, two of them are distinguished by their large surface area: attapulgite and sepiolite. Although, being natural clays, when they are removed from the formation sites, their structural channels may be filled of impurities. The process done to clean these channels is called acid activation. The present work aim to treated samples from both clays by using 3M and 5M HCl solution under ultrasonic waves for 1 hour. The characterization of the clays before and after activation was carried out by SEM/EDS, XRD and surface area measure by method BET. The acid treatments employed were too aggressive, in special that with 5M HCl solution, which results in partial lixiviation of these clays. (author)

  6. Change effects in the land use about the mineral clay

    International Nuclear Information System (INIS)

    Cespedes Payret, C.; Gutierrez, O; Panario, D.; Pineiro, G

    2012-01-01

    The Pampas land changes during the Quaternary, left their mark on the mineralogy of soil clays. This work is oriented to compare the mineralogical composition of the clays and the value of potassium in an eucalyptus forestation. These results show that the mineralogical illite alteration is the cause of its destruction. This clay is the main reservoir of potassium for the agricultural soils

  7. Geological Investigations on Boulder-Clay of E. Groningen

    NARCIS (Netherlands)

    Gijzel, van P.; Overweel, C.J.; Veenstra, H.J.

    1959-01-01

    In this article the results of a study on boulder-clay in the neighbourhood of Winschoten (N.E. Netherlands) are communicated (Chapter I). The underlying sediments of the boulder-clay in this area consist of fine preglacial sands and black clay. In the nuclei of the many drumlins a strongly

  8. Traditional mining and mineralogy of geophagic clays from Limpopo ...

    African Journals Online (AJOL)

    Geophagic clays consumed were whitish, yellowish, khaki and black; mined from hills and mountains, river beds, valleys, excavation sites and termitaria. Geophagic individuals from Free State preferred whitish geophagic clays; and sometimes khaki. Yellowish clays were preferred mostly by geophagic individuals from ...

  9. Polymer-clay nanocomposites obtained by solution polymerization ...

    Indian Academy of Sciences (India)

    Clay minerals can be found all over the world.1 Clay minerals have ... salts or covalent bonding with silanes at the OH edges of the clay. ..... Marras S I, Tsimpliaraki A, Zuburtikudis I and ... Mansoori Y, Roojaei K, Zamanloo M R and Imanzadeh.

  10. Use of clay from kangerlussuaq in the Greenlandic construction industry

    DEFF Research Database (Denmark)

    Belmonte, Louise Josefine; Villumsen, Arne; Ottosen, Lisbeth M.

    2010-01-01

    Clay material from Kangerlussuaq in West Greenland was characterised and its possible use for the production of bricks, expanded clay products and inert filler material was investigated. It was generally found that it was possible to use the clay in all of the above mentioned materials, although,...

  11. Strength and Deformation Properties of Tertiary Clay at Moesgaard Museum

    DEFF Research Database (Denmark)

    Kaufmann, Kristine Lee; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust

    The tertiary clay at Moesgaard Museum near Aarhus in the eastern part of Jutland in Denmark is a highly plastic, glacially disturbed nappe of Viborg Clay. The clay is characterised as a swelling soil, which could lead to damaging of the building due to additional heave of the soil. To take...

  12. Characterization of groundwater dynamics in landslides in varved clays

    NARCIS (Netherlands)

    Van der Spek, J.E.; Bogaard, T.A.; Bakker, M.

    2013-01-01

    Groundwater dynamics may play a significant role in landslides. A detailed model is developed of the groundwater dynamics in landslides in varved clays in the Trièves area in the French Alps. The varved clays consist of a sequence of alternating silt and clay layers, covered by a colluvium layer and

  13. Characterization of groundwater dynamics in landslides in varved clays

    NARCIS (Netherlands)

    Van der Spek, J.E.; Bogaard, T.A.; Bakker, M.

    2013-01-01

    Groundwater dynamics may play a significant role in landslides. A detailed model is developed of the groundwater dynamics in landslides in varved clays in the Trieves area in the French Alps. The varved clays consist of a sequence of alternating silt and clay layers, covered by a colluvium layer and

  14. Enrichment and activation of smectite-poor clay

    Energy Technology Data Exchange (ETDEWEB)

    Sarcevica, Inese; Kostjukovs, Juris; Actint, Andris, E-mail: inese.sarcevicha@gmail.com [Department of Chemistry, University of Latvia, Kr. Valdemara street 48, Riga (Latvia)

    2011-06-23

    A new method of smectite clay enrichment has been developed. The method is based on dispersing clay in a phosphate solution and sequential coagulation. The product of enrichment is characterized with X-ray powder diffraction, wavelength dispersive X-ray fluorescence spectrometry, differential thermal analysis and thermogravimetry. Sorption of methylene blue and hexadecylpyridinium bromide on raw and purified clays was studied.

  15. Evaluation of kaolinite clays of Moa for the production of cement based clinker-calcined clay-limestone (LC3

    Directory of Open Access Journals (Sweden)

    Roger S. Almenares-Reyes

    2016-12-01

    Full Text Available Clay materials from two outcrops of the Moa region were analyzed to determine their potential use as supplementary cementitious material in the production of ternary cements based on limestone-calcined clay. The clays were characterized by atomic absorption spectroscopy (EAA, X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and thermogravimetric analysis (ATG. These methods revealed high aluminum in clays, moderate kaolinite content, a disordered structure and the presence of impurities. The solubility of aluminum and silicon in alkali and the compressive strength of LC3 systems is proportional to their content in clay, being higher for the one with higher kaolinite content and greater structural disorder (outcrop D1, although the clay of both outcrops may constitute supplementary cementitious materials in the production of ternary cements based clinker-calcined clay-limestone. The suitable thermal activation range for both clays is between 650 ° C and 850 ° C.

  16. Understanding the role of clay minerals in the chromium(VI) bioremoval by Pseudomonas aeruginosa CCTCC AB93066 under growth condition: microscopic, spectroscopic and kinetic analysis.

    Science.gov (United States)

    Kang, Chunxi; Wu, Pingxiao; Li, Yuewu; Ruan, Bo; Li, Liping; Tran, Lytuong; Zhu, Nengwu; Dang, Zhi

    2015-11-01

    Laboratory batch experiments were conducted to investigate the role of clay minerals, e.g., kaolinite and vermiculite, in microbial Cr(VI) reduction by Pseudomonas aeruginosa under growth condition in glucose-amended mediums as a method for treating Cr(VI)-contaminated subsurface environment such as soil. Our results indicated that glucose could acted as an essential electron donor, and clay minerals significantly enhanced microbial Cr(VI) reduction rates by improving the consumption rate of glucose and stimulating the growth and propagation of P. aeruginosa. Cr(VI) bioreduction by both free cells and clay minerals-amended cells followed the pseudo-first-order kinetic model, with the latter one fitting better. The mass balance analyses and X-ray photoelectron spectroscopy analysis found that Cr(VI) was reduced to Cr(III) and the adsorption of total chromium on clay minerals-bacteria complex was small, implying that Cr(VI) bioremoval was not mainly due to the adsorption of Cr(VI) onto cells or clay minerals or clay minerals-cells complex but mainly due to the Cr(VI) reduction capacity of P. aeruginosa under the experimental conditions studied (e.g., pH 7). Atomic force microscopy revealed that the addition of clay minerals (e.g. vermiculite) decreased the surface roughness of Cr(VI)-laden cells and changed the cell morphology and dimension. Fourier transform infrared spectroscopy revealed that organic matters such as aliphatic species and/or proteins played an important role in the combination of cells and clay minerals. Scanning electron microscopy confirmed the attachment of cells on the surface of clay minerals, indicating that clay minerals could provide a microenvironment to protect cells from Cr(VI) toxicity and serve as growth-supporting materials. These findings manifested the underlying influence of clay minerals on microbial reduction of Cr(VI) and gave an understanding of the interaction between pollutants, the environment and the biota.

  17. Electrokinetics of samples treated by electrocoagulation methods

    Energy Technology Data Exchange (ETDEWEB)

    Angle, C.W.; Donini, J.C.

    1992-01-01

    The purpose is to study the theory of electrocoagulation during water treatment. Mechanisms proposed in the literature are charge neutralization and dipole-dipole interaction. The electrokinetics of highly concentrated model clay and process clay suspensions, before and after electrocoagulation, are studied experimentally. The charge on treated and untreated dispersions and controls are measured using electrokinetic sonic amplitude and microelectrophoresis techniques. Scanning electron microscopy is used to determine release of aluminum ions onto latex and process clays. The qualitative experimental observations, electrokinetic data, and analysis of aluminum coated particles provide some information on the mechanisms of electrocoagulation, but further studies with dilute dispersions are needed to confirm the charge neutralization mechanism. 10 refs., 4 figs., 3 tabs.

  18. Clays causing adhesion with tool surfaces during mechanical tunnel driving

    Science.gov (United States)

    Spagnoli, G.; Fernández-Steeger, T.; Stanjek, H.; Feinendegen, M.; Post, C.; Azzam, R.

    2009-04-01

    During mechanical excavation with a tunnel boring machine (TBM) it is possible that clays stick to the cutting wheel and to other metal parts. The resulting delays in the progress of construction work, cause great economic damage and often disputes between the public awarding authorities and executing companies. One of the most important factors to reduce successfully the clay adhesion is the use of special polymers and foams. But why does the clay stick to the metal parts? A first step is to recognize which kind of clay mineralogy shows serious adhesion problems. The mechanical properties of clay and clay suspensions are primarily determined by surface chemistry and charge distribution at the interfaces, which in turn affect the arrangement of the clay structure. As we know, clay is a multi-phase material and its behaviour depends on numerous parameters such as: clay mineralogy, clay fraction, silt fraction, sand fraction, water content, water saturation, Atterberg limits, sticky limit, activity, cation exchange capacity, degree of consolidation and stress state. It is therefore likely that adhesion of clay on steel is also affected by these clay parameters. Samples of clay formations, which caused problems during tunnel driving, will be analyzed in laboratory. Mineralogical analyses (diffractometry, etc.) will be carried out to observe which minerals are responsible for adherence problems. To manipulate the physical properties, batch tests will be carried out in order to eliminate or reduce the adhesion on tool surfaces through variation of the zeta potential. Second step is the performance of vane shear tests on clay samples. Different pore fluid (distilled water, pure NaCl solution, ethanol and methanol) will be used to study the variation of the mechanical behaviour of clay depending on the dielectric constant of the fluids. This project is funded by the German Federal Ministry of Education and Research (BMBF) and the DFG (German Research Foundation) in the

  19. Clay particles as binder for earth buildings materials: a fresh look into rheology of dense clay suspensions

    Directory of Open Access Journals (Sweden)

    Landrou Gnanli

    2017-01-01

    Full Text Available In the ceramic industry and in many sectors, clay minerals are widely used. In earthen construction technique, clay plays a crucial role in the processing. The purpose of this research is to understand and modify the clay properties in earth material to propose an innovative strategy to develop a castable earth-based material. To do so, we focused on the modification of clay properties at fresh state with inorganic additives. As the rheological behaviour of clays is controlled by their surface charge, the addition of phosphate anion allows discussing deep the rheology of concentrated clay suspensions. We highlighted the thixotropic and shear thickening behaviour of a dispersed kaolinite clay suspensions. Indeed, by adding sodium hexametaphosphate the workability of clay paste increases and the behaviour is stable during time after a certain shear is applied. Moreover, we stress that the aging and the shift in critical strain in clay system are due to the re-arrangement of clay suspension and a decrease of deformation during time. The understanding of both effect: thixotropy and aging are crucial for better processing of clay-based material and for self-compacting clay concrete. Yet, studies need to pursue to better understand the mechanism.

  20. Clay particles as binder for earth buildings materials: a fresh look into rheology of dense clay suspensions

    Science.gov (United States)

    Landrou, Gnanli; Brumaud, Coralie; Habert, Guillaume

    2017-06-01

    In the ceramic industry and in many sectors, clay minerals are widely used. In earthen construction technique, clay plays a crucial role in the processing. The purpose of this research is to understand and modify the clay properties in earth material to propose an innovative strategy to develop a castable earth-based material. To do so, we focused on the modification of clay properties at fresh state with inorganic additives. As the rheological behaviour of clays is controlled by their surface charge, the addition of phosphate anion allows discussing deep the rheology of concentrated clay suspensions. We highlighted the thixotropic and shear thickening behaviour of a dispersed kaolinite clay suspensions. Indeed, by adding sodium hexametaphosphate the workability of clay paste increases and the behaviour is stable during time after a certain shear is applied. Moreover, we stress that the aging and the shift in critical strain in clay system are due to the re-arrangement of clay suspension and a decrease of deformation during time. The understanding of both effect: thixotropy and aging are crucial for better processing of clay-based material and for self-compacting clay concrete. Yet, studies need to pursue to better understand the mechanism.

  1. Studies on incorporation of exfoliated bentonitic clays in polyurethane foams for increasing flame retardancy

    International Nuclear Information System (INIS)

    Quagliano, J; García, Irma Gavilán

    2012-01-01

    In this contribution we report the results of studying the incorporation of exfoliated bentonitic clays into polyurethane foams. A suspension in water of a sodium bentonite from Argentine Patagonia was interchanged with cetyl trimethyl ammonium bromide (CTAB) for 4 h at 80°C, rendering an exfoliated clay, which is nanometric in only one dimension. This nanoclay, when dispersed in the polyurethane, resulted in the same fire retardancy rating (UL-94) than when polyurethane was treated with a commercial nanoclay. Scanning electron microscopy (SEM) at low augmentations of polyurethane samples treated with the synthethized nanoclay (2,5% w/w) showed no differences respect to untreated polyurethane, except for the irregularity of void edges.

  2. A clay-shoveler's fracture with renal transplantation and osteoporosis: a case report

    Directory of Open Access Journals (Sweden)

    Unay Koray

    2008-06-01

    Full Text Available Abstract Introduction Clay-shoveler's fracture is a rare cervicodorsal spinous process fracture and there is little information regarding the prognosis of patients with this condition in conjunction with osteoporosis and corticosteroid use. Case presentation A 39-year-old man was admitted to our institution with a 6-month history of cervicodorsal pain prior to admission. The patient had previously undergone renal transplantation and was on corticosteroids, and had developed osteoporosis. We treated him with a cervical collar, non-steroidal anti-inflammatory agents and alendronate. The patient was advised against performing weight-bearing activities for 6 months. Conclusion Clay-shoveler's fracture with osteoporosis and corticosteroid use presented by fracture of the cervicodorsal aspect of the spinous processes may be successfully treated with a collar, alendronate and long-term rest.

  3. Pure and impure clays and their firing products

    International Nuclear Information System (INIS)

    Murad, E.; Wagner, U.

    1989-01-01

    Moessbauer spectroscopy is highly suited for the study of clays whose industrial uses depend on the iron content. Reactions that take place during clay firing can be readily monitored by Moessbauer spectroscopy. Following dehydroxylation of clay minerals, the quadrupole splitting of octahedrally coordinated iron (III) increases abruptly, but reverts to lower values upon the formation of new, better ordered phases at higher temperatures. It is also shown that iron oxides may account for a considerably higher proportion of the total iron content of many clays than is commonly recognized, and their existence must be taken into consideration for a correct interpretation of the Moessbauer spectra of clays. (orig.)

  4. Performance Study of the Natural Rubber Composite with Clay Minerals

    International Nuclear Information System (INIS)

    Nyo Nyo Myint; Tin Tin Aye; Kyaw Myo Naing; Nyunt Wynn

    2008-03-01

    The preparation, characterization and some applications of natural rubber clay composite have been studied. This study investigated the possibility of natural rubber latex to replace some part of natural clays. In formulation of rubber clay composite from natural rubber latex and various clay minerals, three main steps were involved (i) preparation of latex cream (ii) prevulcanization of latex cream (iii) mixing vulcanized latex compound, with other ingredients. In each step, several parameters have been carefully investigated to optimize the performance of natural rubber clay composite production. The composite products were of better quality and can be considered to be more cost effective.

  5. Clay minerals behaviour in thin sandy clay-rich lacustrine turbidites (Lake Hazar, Turkey)

    Science.gov (United States)

    El Ouahabi, Meriam; Hubert-Ferrari, Aurelia; Lamair, Laura; Hage, Sophie

    2017-04-01

    Turbidites have been extensively studied in many different areas using cores or outcrop, which represent only an integrated snapshot of a dynamic evolving flow. Laboratory experiments provide the missing relationships between the flow characteristics and their deposits. In particular, flume experiments emphasize that the presence of clay plays a key role in turbidity current dynamics. Clay fraction, in small amount, provides cohesive strength to sediment mixtures and can damp turbulence. However, the degree of flocculation is dependent on factors such as the amount and size of clay particles, the surface of clay particles, chemistry and pH conditions in which the clay particles are dispersed. The present study focuses on thin clayey sand turbidites found in Lake Hazar (Turkey) occurring in stacked thin beds. Depositional processes and sources have been previously studied and three types were deciphered, including laminar flows dominated by cohesion, transitional, and turbulence flow regimes (Hage et al., in revision). For the purpose of determine the clay behavior in the three flow regimes, clay mineralogical, geochemical measurements on the cores allow characterising the turbidites. SEM observations provide further information regarding the morphology of clay minerals and other clasts. The study is particularly relevant given the highly alkaline and saline water of the Hazar Lake. Clay minerals in Hazar Lake sediments include kaolinite (1:1-type), illite and chlorite (2:1-type). Hazar lake water is alkaline having pH around 9.3, in such alkaline environment, a cation-exchange reaction takes place. Furthermore, in saline water (16‰), salts can act as a shield and decrease the repulsive forces between clay particle surfaces. So, pH and salt content jointly impact the behaviour of clays differently. Since the Al-faces of clay structures have a negative charge in basic solutions. At high pH, all kaolinite surfaces become negative-charged, and then kaolinite

  6. Geotechnical Characterization of Mined Clay from Appalachian Ohio: Challenges and Implications for the Clay Mining Industry

    Science.gov (United States)

    Moran, Anthony R.; Hettiarachchi, Hiroshan

    2011-01-01

    Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling. PMID:21845150

  7. Proceedings of the NEA Clay Club Workshop on Clay characterisation from nanoscopic to microscopic resolution

    International Nuclear Information System (INIS)

    2013-01-01

    A wide spectrum of argillaceous media are being considered in Nuclear Energy Agency (NEA) member countries as potential host rocks for the final, safe disposal of radioactive waste, and/or as major constituent of repository systems in which wastes will be emplaced. In this context, the NEA established the Working Group on the 'Characterisation, the Understanding and the Performance of Argillaceous Rocks as Repository Host Formations' in 1990, informally known as the 'Clay Club'. The Clay Club examines various argillaceous rocks that are being considered for the underground disposal of radioactive waste, ranging from soft clays to indurated shales. Very generally speaking, these clay rocks are composed of fine-grained minerals showing pore sizes from < 2 nm (micropores) up to > 50 nm (macro-pores). The water flow, solute transport and mechanical properties are largely determined by this microstructure, the spatial arrangement of the minerals and the chemical pore water composition. Examples include anion accessible ('geochemical') porosity and macroscopic membrane effects (chemical osmosis, hyper-filtration), geomechanical properties and the characteristics of two-phase flow properties (relevant for gas transport). At the current level of knowledge, there is a strong need to improve the nanoscale description of the phenomena observed at a more macroscopic scale. However, based on the scale of individual clay-minerals and pore sizes, for most of the imaging techniques this resolution is a clear challenge. The workshop, hosted by the Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute of Technology (KIT) in the Akademiehotel Karlsruhe (Germany) from 6 to 8 September 2011, was intended to give, inter alia, a discussion platform on: - The current state-of-the-art of different spectro-microscopic methods - New developments addressing the above mentioned knowledge gaps in clays. - The perception of the interplay between geometry

  8. Geotechnical Characterization of Mined Clay from Appalachian Ohio: Challenges and Implications for the Clay Mining Industry

    Directory of Open Access Journals (Sweden)

    Anthony R. Moran

    2011-06-01

    Full Text Available Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for the soils originated from the same source, provided that the testing techniques applied are standard, but mined clay from Appalachian Ohio has shown drastic differences in particle size distribution depending on the sampling and/or laboratory processing methods. Sometimes more than a 10 percent decrease in the clay content is observed in the samples collected at the stockpiles, compared to those collected through reverse circulation drilling. This discrepancy poses a challenge to geotechnical engineers who work on the prequalification process of RSL material as it can result in misleading estimates of the hydraulic conductivity of the samples. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods can affect the grain-size distributions. The variation in the clay content was determined to be due to heavy concentrations of shale fragments in the clayey soils. It was also concluded that, in order to obtain reliable grain size distributions from the samples collected at a stockpile of mined clay, the material needs to be processed using a soil grinder. Otherwise, the samples should be collected through drilling.

  9. Utilisation of Sepidrud dam basin sediments in fired clay bricks: laboratory scale experiment

    OpenAIRE

    Jamshidi-Chenari, R.; Rabanifar, H.; Veiseh, S.

    2015-01-01

    The prevailing disposal methods for dam basin sediments are not free from the environmental pollution and the ecological imbalance. At present, a new way to treat the dredged sediments to manufacture bricks is being investigated, prioritizing waste recovery over its deposition in landfills. However, construction materials such as clay bricks must comply with the international and local standards. Considering the perpetual availability of the sediments, particle sizing and their chemical compo...

  10. Clay mineral type effect on bacterial enteropathogen survival in soil.

    Science.gov (United States)

    Brennan, Fiona P; Moynihan, Emma; Griffiths, Bryan S; Hillier, Stephen; Owen, Jason; Pendlowski, Helen; Avery, Lisa M

    2014-01-15

    Enteropathogens released into the environment can represent a serious risk to public health. Soil clay content has long been known to have an important effect on enteropathogen survival in soil, generally enhancing survival. However, clay mineral composition in soils varies, and different clay minerals have specific physiochemical properties that would be expected to impact differentially on survival. This work investigated the effect of clay materials, with a predominance of a particular mineral type (montmorillonite, kaolinite, or illite), on the survival in soil microcosms over 96 days of Listeria monocytogenes, Salmonella Dublin, and Escherichia coli O157. Clay mineral addition was found to alter a number of physicochemical parameters in soil, including cation exchange capacity and surface area, and this was specific to the mineral type. Clay mineral addition enhanced enteropathogen survival in soil. The type of clay mineral was found to differentially affect enteropathogen survival and the effect was enteropathogen-specific. © 2013.

  11. Sorption of Pu onto some kinds of clay

    International Nuclear Information System (INIS)

    Jia Haihong; Si Gaohua; Liu Wei; Yu Jing

    2010-01-01

    There are rich clay mines holding in one area, so it's necessary to know about these clays' sorption capacity to Pu, for building radioactive waste repository in the area. Distribution coefficients of Pu onto different clays were acquired in static method, with the result about 104. The size of clay is different, but the result of Kds is near. In addition, it's estimated how far Pu moves in the most rapid speed in the clay based on these Kids', disregarding the influence of Pu-colloid. In a word, as a kind of backfilling material clays in the area can effectively prevent Pu from moving to environment, and when designing the backfilling layer, it's not necessary to catch clays through NO.200 sieve, if only considering the influence of Kd. (authors)

  12. Feasibility of classification of clay minerals by using PAS

    International Nuclear Information System (INIS)

    Honda, Y; Yoshida, Y; Akiyama, Y; Nishijima, S

    2015-01-01

    After the nuclear power plant disaster, the evaluation of radioactive Cs kept in soil, especially in clay minerals and the elucidation of its movement are urgent subjects to promote decontamination. It is known that the extractable level of Cs depends on the sort of clay minerals. We tried to find the characteristics of clay minerals belonging to phillosilicate group using positron annihilation spectroscopy (PAS) and the relationship between the results of PAS and the amounts of substantially extracted Cs from the clay minerals. The results showed that each clay mineral was found to be distinguishable from other clay minerals by PAS and the extraction rate of Cs was different among those clay minerals, however the direct correlation between the results of PAS and the extraction rates of Cs was not found. (paper)

  13. Organically modified clay removes oil from water

    International Nuclear Information System (INIS)

    Alther, G.R.

    1995-01-01

    When bentonite or other clays and zeolites are modified with quaternary amines, they become organophilic. Such modified bentonites are used to remove mechanically emulsified oil and grease, and other sparingly soluble organics. If the organoclay is granulated, it is placed into a liquid phase carbon filter vessel to remove FOG's and chlorinated hydrocarbons. In this application the clay is mixed with anthrazite to prevent early plugging of the filter by oil or grease droplets. In batch systems a powered organoclay is employed. Types of oil found in water can include fats, lubricants, cutting fluids, heavy hydrocarbons such as tars, grease, crude oil, diesel oils; and light hydrocarbons such as kerosene, jet fuel, and gasoline

  14. Clay-based geothermal drilling fluids

    Energy Technology Data Exchange (ETDEWEB)

    Guven, N.; Carney, L.L.; Lee, L.J.; Bernhard, R.P.

    1982-11-01

    The rheological properties of fluids based on fibrous clays such as sepiolite and attapulgite have been systematically examined under conditions similar to those of geothermal wells, i.e. at elevated temperatures and pressures in environments with concentrated brines. Attapulgite- and sepiolite-based fluids have been autoclaved at temperatures in the range from 70 to 800/sup 0/F with the addition of chlorides and hydroxides of Na, K, Ca, and Mg. The rheological properties (apparent and plastic viscosity, fluid loss, gel strength, yield point, and cake thickness) of the autoclaved fluids have been studied and correlated with the chemical and physical changes that occur in the clay minerals during the autoclaving process.

  15. Organoclays obtaining starting up of clays sodium

    International Nuclear Information System (INIS)

    Silva, M.M. da; Mota, M.F.; Oliveira, G.C. de; Rodrigues, M.G.F.

    2012-01-01

    Clays have several applications in many areas of fields of technology, however, modification of these materials using organic compounds can be performed to obtain further hydrophobic materials, for applications in the adsorption of organic pollutants. This study aimed to analyze the effects of modifying two clays using sodium quaternary ammonium surfactants through ion exchange reaction process, in obtaining organoclays. The samples with sodium and organoclays were characterized by the techniques of X-ray diffraction (XRD), Infrared Spectroscopy in the region (IV), Gravimetric and Differential Thermal Analysis (DTA / TG) and organic adsorption tests. The results show that the process of obtaining organoclay is efficient, and materials have the potential for future applications in removing organic contaminants. (author)

  16. Rheological properties of sodium smectite clay

    International Nuclear Information System (INIS)

    Boergesson, L.; Hoekmark, H.; Karnland, O.

    1988-12-01

    The rheological properties of Na-smectite Mx-80 have been investigated by various laboratory tests. The investigations include determination of the hydraulic conductivity, the undrained stress-strain-strength properties, the creep properties, the compression and swelling properties in drained and undrained conditions and the undrained thermomechanical properties. Measurements have been made at different densities, clay/sand mixtures and pore water compositions. The influence of temperature, rate of strain and testing technique has also been considered. The investigation has led to a supply of basic data for the material models which will be used at performance calculations. The results have also increased the general understanding of the function of smectitic clay as buffer material. The microstructural behaviour has been considered at the validation of the different test results and the validity of the effective stress theory has been discussed. Comparisons with the properties of Ca-smectite have also been made. (orig.)

  17. Chemical buffering capacity of clay rock

    International Nuclear Information System (INIS)

    Beaucaire, C.; Pearson, F.J.; Gautschi, A.

    2004-01-01

    The long-term performance of a nuclear waste repository is strongly dependent on the chemical properties of the host rock. The host rock establishes the chemical environment that determines such important performance attributes as radionuclide solubilities from the waste and the transport rates from the repository to the accessible environment. Clay-rich rocks are especially favourable host rocks because they provide a strong buffering capacity to resist chemical changes prompted either internally, by reactions of the waste itself and emplacement materials, or externally, by changes in the hydrologic systems surrounding the host rock. This paper will focus on three aspects of the stability of clay-rich host rocks: their ability to provide pCO 2 and redox buffering, and to resist chemical changes imposed by changes in regional hydrology and hydro-chemistry. (authors)

  18. Gravel-Sand-Clay Mixture Model for Predictions of Permeability and Velocity of Unconsolidated Sediments

    Science.gov (United States)

    Konishi, C.

    2014-12-01

    Gravel-sand-clay mixture model is proposed particularly for unconsolidated sediments to predict permeability and velocity from volume fractions of the three components (i.e. gravel, sand, and clay). A well-known sand-clay mixture model or bimodal mixture model treats clay contents as volume fraction of the small particle and the rest of the volume is considered as that of the large particle. This simple approach has been commonly accepted and has validated by many studies before. However, a collection of laboratory measurements of permeability and grain size distribution for unconsolidated samples show an impact of presence of another large particle; i.e. only a few percent of gravel particles increases the permeability of the sample significantly. This observation cannot be explained by the bimodal mixture model and it suggests the necessity of considering the gravel-sand-clay mixture model. In the proposed model, I consider the three volume fractions of each component instead of using only the clay contents. Sand becomes either larger or smaller particles in the three component mixture model, whereas it is always the large particle in the bimodal mixture model. The total porosity of the two cases, one is the case that the sand is smaller particle and the other is the case that the sand is larger particle, can be modeled independently from sand volume fraction by the same fashion in the bimodal model. However, the two cases can co-exist in one sample; thus, the total porosity of the mixed sample is calculated by weighted average of the two cases by the volume fractions of gravel and clay. The effective porosity is distinguished from the total porosity assuming that the porosity associated with clay is zero effective porosity. In addition, effective grain size can be computed from the volume fractions and representative grain sizes for each component. Using the effective porosity and the effective grain size, the permeability is predicted by Kozeny-Carman equation

  19. Moessbauer spectroscopy of iron in clay minerals

    International Nuclear Information System (INIS)

    Raclavsky, K.; Sitek, J.; Lipka, J.

    1975-01-01

    Selected pure clay minerals predominantly of Czechoslovak origin were studied, such as montmorillonite, nontronite, beidellite, glauconite, seladonite, illite, vermiculite, saponite, palygorskite, goethite. Moessbauer measurements were performed at room temperature with a 57 Co in Pd source. The spectra were fitted by the least square method. The parameters of the measured Moessbauer spectra are given. The values of isomer shifts, quadrupole splittings and line widths were obtained with an error of +- 0.03 mm/sec. (Z.S.)

  20. Octyl Phenol Synthesis Using Natural Clays

    Directory of Open Access Journals (Sweden)

    S. Casuscelli

    2000-03-01

    Full Text Available A series of clay minerals, HB, NB and Al-PILC have been studied in the alkylation reactions of 2-octanol with phenol at 180°C, under conditions of alcohol/phenol = 1 (mole ratio and W/FAo °= 64,27 ghmol-1. The selectivity of Al-PILC was 77,12% for octyl phenol and 16,5% for dioctyl phenol.

  1. Spectromicroscopy of Fe distributions in clay microcrystals

    Energy Technology Data Exchange (ETDEWEB)

    Grundl, T. [Univ. of Wisconsin, Milwaukee, WI (United States); Cerasari, S.; Garcia, A. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Clays are ubiquitous crystalline particles found in nature that are responsible for contributing to a wide range of chemical reactions in soils. The structure of these mineral particles changes when the particle is hydrated ({open_quotes}wet{close_quotes}), from that when it is dry. This makes a study of the microscopic distribution of chemical content of these nanocrystals difficult using standard techniques that require vacuum. In addition to large structural changes, it is likely that chemical changes accompany the drying process. As a result, spectroscopic measurements on dried clay particles may not accurately reflect the actual composition of the material as found in the environment. In this work, the authors extend the use of the ALS Spectromicroscopy Facility STXM to high spectral and spatial resolution studies of transition metal L-edges in environmental materials. The authors are studying mineral particles of montmorillonite, which is an Fe bearing clay which can be prepared with a wide distribution of Fe concentrations, and with Fe occupying different substitutional sites.

  2. Characterization of electron-beam-modified surface coated clay fillers and their influence on physical properties of rubbers

    International Nuclear Information System (INIS)

    Ray, Sudip; Bhowmick, Anil K.; Sarma, K.S.S.; Majali, A.B.; Tikku, V.K.

    2002-01-01

    A novel process of surface modification of clay filler has been developed by coating this with an acrylate monomer, trimethylol propane triacrylate (TMPTA) or a silane coupling agent, triethoxy vinyl silane (TEVS) followed by electron beam irradiation. Characterization of these surface modified fillers has been carried out by Fourier-transform infrared analysis (FTIR), electron spectroscopy for chemical analysis (ESCA), wettability by dynamic wicking method measuring the rise of a liquid through a filler-packed capillary tube and water flotation test, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). Presence of the acrylate and the silane coupling agent on the modified fillers has been confirmed from FTIR, ESCA, and EDX studies, which has also been supported by TGA studies. The contact angle measurement by dynamic wicking method suggests improvement in hydrophobicity of the treated fillers, which is supported by water flotation test especially in the case of silanized clay. However, XRD studies demonstrate that the entire modification process does not affect the bulk properties of the fillers. Finally, both unmodified and modified clay fillers have been incorporated in styrene butadiene rubber (SBR) and nitrile rubber (NBR). Rheometric and mechanical properties reveal that there is a definite improvement using these modified fillers specially in the case of silanized clay compared to the control sample, probably due to successful enhancement in interaction between the treated clay and the base polymer

  3. Characterization of electron-beam-modified surface coated clay fillers and their influence on physical properties of rubbers

    Science.gov (United States)

    Ray, Sudip; Bhowmick, Anil K.; Sarma, K. S. S.; Majali, A. B.; Tikku, V. K.

    2002-12-01

    A novel process of surface modification of clay filler has been developed by coating this with an acrylate monomer, trimethylol propane triacrylate (TMPTA) or a silane coupling agent, triethoxy vinyl silane (TEVS) followed by electron beam irradiation. Characterization of these surface modified fillers has been carried out by Fourier-transform infrared analysis (FTIR), electron spectroscopy for chemical analysis (ESCA), wettability by dynamic wicking method measuring the rise of a liquid through a filler-packed capillary tube and water flotation test, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). Presence of the acrylate and the silane coupling agent on the modified fillers has been confirmed from FTIR, ESCA, and EDX studies, which has also been supported by TGA studies. The contact angle measurement by dynamic wicking method suggests improvement in hydrophobicity of the treated fillers, which is supported by water flotation test especially in the case of silanized clay. However, XRD studies demonstrate that the entire modification process does not affect the bulk properties of the fillers. Finally, both unmodified and modified clay fillers have been incorporated in styrene butadiene rubber (SBR) and nitrile rubber (NBR). Rheometric and mechanical properties reveal that there is a definite improvement using these modified fillers specially in the case of silanized clay compared to the control sample, probably due to successful enhancement in interaction between the treated clay and the base polymer.

  4. Study of the Effect of Clay Particles on Low Salinity Water Injection in Sandstone Reservoirs

    Directory of Open Access Journals (Sweden)

    Sina Rezaei Gomari

    2017-03-01

    Full Text Available The need for optimal recovery of crude oil from sandstone and carbonate reservoirs around the world has never been greater for the petroleum industry. Water-flooding has been applied to the supplement primary depletion process or as a separate secondary recovery method. Low salinity water injection is a relatively new method that involves injecting low salinity brines at high pressure similar to conventional water-flooding techniques, in order to recover crude oil. The effectiveness of low salinity water injection in sandstone reservoirs depends on a number of parameters such as reservoir temperature, pressure, type of clay particle and salinity of injected brine. Clay particles present on reservoir rock surfaces adsorb polar components of oil and modify wettability of sandstone rocks to the oil-wet state, which is accountable for the reduced recovery rates by conventional water-flooding. The extent of wettability alteration caused by three low salinity brines on oil-wet sandstone samples containing varying clay content (15% or 30% and type of clay (kaolinite/montmorillonite were analyzed in the laboratory experiment. Contact angles of mica powder and clay mixture (kaolinite/montmorillonite modified with crude oil were measured before and after injection with three low salinity sodium chloride brines. The effect of temperature was also analyzed for each sample. The results of the experiment indicate that samples with kaolinite clay tend to produce higher contact angles than samples with montmorillonite clay when modified with crude oil. The highest degree or extent of wettability alteration from oil-wet to intermediate-wet state upon injection with low salinity brines was observed for samples injected with brine having salinity concentration of 2000 ppm. The increase in temperature tends to produce contact angles values lying in the higher end of the intermediate-wet range (75°–115° for samples treated at 50 °C, while their corresponding

  5. Iodide Sorption to Clays and the Relationship to Surface Charge and Clay Texture - 12356

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Andrew; Kruichiak, Jessica; Tellez, Hernesto; Wang, Yifeng [Sandia National Laboratories, Albuquerque, NM 87185 (United States)

    2012-07-01

    Iodine is assumed to behave conservatively in clay barriers around nuclear waste repositories and in natural sediments. Batch experiments tend to show little to no sorption, while in column experiments iodine is often retarded relative to tritiated water. Current surface complexation theory cannot account for negatively charged ion sorption to a negatively charged clay particle. Surface protonation and iodide sorption to clay minerals were examined using surface titrations and batch sorption experiments with a suite of clay minerals. Surface titrations were completed spanning a range of both pH values and ionic strengths. For reference, similar titrations were performed on pure forms of an Al-O powder. The titration curves were deconvoluted to attain the pKa distribution for each material at each ionic strength. The pKa distribution for the Al-O shows two distinct peaks at 4.8 and 7.5, which are invariant with ionic strength. The pKa distribution of clays was highly variable between the different minerals and as a function of ionic strength. Iodide sorption experiments were completed at high solid:solution ratios to exacerbate sorption properties. Palygorskite and kaolinite had the highest amount of iodide sorption and montmorillonite had the least. (authors)

  6. Influence of clay organic modifier on morphology and performance of poly(ε-caprolactone/clay nanocomposites

    Directory of Open Access Journals (Sweden)

    Nikolić Marija S.

    2015-01-01

    Full Text Available Two series of poly(e-caprolactone nanocomposites with different organo-modified clays (1 to 8 wt% were prepared by the solution casting method. Organoclays with polar (Cloisite®C30B and nonpolar (Cloisite®C15A organic modifier and with different miscibility with poly(e-caprolactone matrix, were chosen. Exfoliated and/or intercalated nanocomposite’s structures were obtained by using high dilution and an ultrasonic treatment for the composite preparation. The effect of the surface modification and clay content on the morphology, mechanical and thermal properties of the nanocomposites was studied. Scanning electron microscopy excluded the formation of microcomposite. The wide-angle X-ray diffraction analysis revealed that the tendency toward exfoliated structure is higher for the Cloisite®C30B, which had better miscibility with poly(e-caprolactone matrix. Differences in spherulites’ sizes and morphology between two series of the nanocomposites were observed by the optical microscopy performed on as-casted films. Enthalpies of fusion and degrees of crystallinity were higher for nanocomposites than for neat poly(e-caprolactone and increase with the clay loading in both series, as a consequence of the clay nucleating effect. Decreased thermal stability of nanocomposites was ascribed to thermal instability of organic modifiers of the clays. The Halpin-Tsai model was used to compare the theoretically predicted values of the Young’s modulus with experimentally obtained ones in tensile tests.[Projekat Ministarstva nauke Republike Srbije, br. 172062

  7. Atrazine biodegradation modulated by clays and clay/humic acid complexes

    International Nuclear Information System (INIS)

    Besse-Hoggan, Pascale; Alekseeva, Tatiana; Sancelme, Martine; Delort, Anne-Marie; Forano, Claude

    2009-01-01

    The fate of pesticides in the environment is strongly related to the soil sorption processes that control not only their transfer but also their bioavailability. Cationic (Ca-bentonite) and anionic (Layered Double Hydroxide) clays behave towards the ionisable pesticide atrazine (AT) sorption with opposite tendencies: a noticeable sorption capacity for the first whereas the highly hydrophilic LDH showed no interactions with AT. These clays were modified with different humic acid (HA) contents. HA sorbed on the clay surface and increased AT interactions. The sorption effect on AT biodegradation and on its metabolite formation was studied with Pseudomonas sp. ADP. The biodegradation rate was greatly modulated by the material's sorption capacity and was clearly limited by the desorption rate. More surprisingly, it increased dramatically with LDH. Adsorption of bacterial cells on clay particles facilitates the degradation of non-sorbed chemical, and should be considered for predicting pesticide fate in the environment. - The biodegradation rate of atrazine was greatly modulated by adsorption of the pesticide and also bacterial cells on clay particles.

  8. Evaluation of the bleaching flux in clays containing hematite and different clay minerals

    International Nuclear Information System (INIS)

    Silva Junior, E.M.; Lusa, T.; Silva, T.M.; Medeiros, B.B.; Santos, G.R. dos; Morelli, M.R.

    2016-01-01

    Previous studies have shown that the addition of a synthetic flux in a clay mineral constituted by illite phase in the presence of iron oxide with the hematite, promotes color change of the firing products, making the reddish color firing into whiteness. This flow is constituted of a vitreous phase of the silicates family obtained by fusion/solidification of oxides and carbonates. Thus, the objective of this work was that of studying the interaction of the iron element in the final color mechanism of the different types of mineral crystal phase of the clays. In order to study the phenomenon, we obtained different compositions between the select clays and the synthetic flow, and characterization using X-ray diffraction (XRD) and visual analysis. The results showed that the action of the synthetic flow as a modifying agent for color depends on the mineral crystal phase of the clays. The color firing modification does not occur in the clays content high levels of kaolinite mineral phase. (author)

  9. Evaluation of the permeability of microporous membranes polyamide 6 / clay bentonite for water-oil separation

    International Nuclear Information System (INIS)

    Medeiros, P.S.S.; Medeiros, K.M.; Araujo, E.M.; Lira, H.L.

    2014-01-01

    The petroleum refining industries have faced major problems in relation to the treatment of their effluents before disposal into the environment. Among the conventional technologies treatment of these effluents, the process of oil-water separation by means of membranes has been extensively used, for having enormous potentiality. Therefore, in this study, hybrid membranes of polyamide 6/ bentonite clay were produced by the technique of phase inversion and by precipitation of the solution from the nanocomposites obtained by melt intercalation. The clay was organically modified with the quaternary ammonium salt (Cetremide®). The nanocomposites were obtained from (PA6) with untreated (AST) and treated clay (ACT), which were subsequently characterized by X-ray diffraction (XRD). Already membranes were characterized by XRD, scanning electron microscopy (SEM) and flow measurements. From the XRD results, it was observed an exfoliated and/or partially exfoliated structure for the nanocomposites and for the membranes. From SEM images it was observed that the presence of AST and ACT clays in the polymeric matrix caused changes in membrane morphology and pore formation. The flow with distilled water in the membranes showed a decrease initially and then followed by stability. All membranes tested in the process of separating emulsions of oil in water, particularly those of nanocomposites obtained a significant reduction of oil concentration in the permeate, thus showing that these membranes have a great potential to be applied to the water-oil separation. (author)

  10. SODIUM TITANATE NANOBELT AS A MICROPARTICLE TO INDUCE CLAY FLOCCULATION WITH CPAM

    Directory of Open Access Journals (Sweden)

    Wenxia Liu

    2010-07-01

    Full Text Available Sodium titanate nanobelt was synthesized by treating titanium dioxide hydrothermally in concentrated sodium hydroxide solution. The product was characterized by SEM analysis and zeta potential measurement. It served as a microparticle to constitute a microparticle retention system with cationic polyacrylamide (CPAM, while the microparticle system was employed to induce the flocculation of kaolin clay. The flocculation behavior of kaolin clay in such a system was investigated by using a photometric dispersion analyzer connected with a dynamic drainage jar. It was found that the sodium titanate nanobelt carried negative charges and had a lower zeta potential at higher pH. It gave a large synergistic flocculation effect with CPAM at a very low dosage, and showed higher flocculation effect with CPAM under neutral and weak alkaline conditions. A suitably high shear level was helpful for the re-flocculation of clay by sodium titanate nanobelt. The clay flocculation induced by CPAM/titanate nanobelt system demonstrated high shear resistance and also generated dense flocs.

  11. HDPE/clay hybrids: the effect of clay modified with poly(diphenyl siloxanes) on thermal and rheological properties

    Energy Technology Data Exchange (ETDEWEB)

    Monasterio, Fernanda E.; Carrera, Maria C.; Erdmann, Eleonora; Destefanis, Hugo A., E-mail: ferelenakq@gmail.co [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Buenos Aires (Argentina). Inst. de Investigaciones para la Industria Quimica; Pita, Victor J.R.R.; Dias, Marcos L. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Profa. Eloisa Mano

    2009-07-01

    Poly(diphenyl siloxanes) (PDPhS) were synthesized in presence of organophilic clay in order to modify its nano structure. Two silane monomers were used: dimethoxydiphenylsilane and dichlorodiphenylsilane. The following characterizations were performed for all clays: XRD, FTIR and TGA/DTG. These siloxane-modified clays were more hydrophobic and had enhanced thermal stability. Solvent extraction was carried out in the siloxane-modified clays and the PDPhS soluble fraction analyzed according the molecular weight via GPC. The presence of free and grafted oligomers on clay surface was identified. The modified clays were added to HDPE by melt processing to obtain HDPE/clay hybrids which exhibited marked differences in the rheological behavior when compared with neat HDPE. (author)

  12. HDPE/clay hybrids: the effect of clay modified with poly(diphenyl siloxanes) on thermal and rheological properties

    International Nuclear Information System (INIS)

    Monasterio, Fernanda E.; Carrera, Maria C.; Erdmann, Eleonora; Destefanis, Hugo A.; Pita, Victor J.R.R.; Dias, Marcos L.

    2009-01-01

    Poly(diphenyl siloxanes) (PDPhS) were synthesized in presence of organophilic clay in order to modify its nano structure. Two silane monomers were used: dimethoxydiphenylsilane and dichlorodiphenylsilane. The following characterizations were performed for all clays: XRD, FTIR and TGA/DTG. These siloxane-modified clays were more hydrophobic and had enhanced thermal stability. Solvent extraction was carried out in the siloxane-modified clays and the PDPhS soluble fraction analyzed according the molecular weight via GPC. The presence of free and grafted oligomers on clay surface was identified. The modified clays were added to HDPE by melt processing to obtain HDPE/clay hybrids which exhibited marked differences in the rheological behavior when compared with neat HDPE. (author)

  13. Strengthening and stress relaxation of Opalinus Clay

    International Nuclear Information System (INIS)

    Schulze, Otto

    2010-01-01

    Document available in extended abstract form only. Full text follows: In the framework of the EU-project NF-PRO (e.g. RTDC-5, Synthesis Report, D-No 5.2.3), special emphasis was put on the investigation and modelling of near-field processes in a candidate host rock: http://project.nf-pro.org/workspaces/rtdc5/deliverables/d5_2_3_rtdc_5_synthesis_report_final_version. The coupled TMHC-processes under consideration mainly concern the interaction between the host rock in and near to the EDZ and the waste products in its immediate vicinity. With respect to long-term safety analyses, there is no doubt that a sound process understanding is required. However, safe disposal also requires a suitable multi-barrier-system. This has to consist of technical and geo-technical barriers (e.g. container and backfill) but also of a strong geological barrier. Comparing the self-sealing capacity of the candidate host rocks, i.e. salt, clay and crystalline rock formations, where underground rooms will be inevitably backfilled only in part for technical reasons, in a salt formation convergence by viscous deformation provokes the re-establishing of a tight system, whereas in a crystalline rock formation long-term isolation has to be guaranteed solely by the technical and geotechnical components. This work is concentrated on the question, whether convergence and reduction of open space by long-term creep will take place also in a clay-stone formation, where laboratory investigation on Opalinus Clay from the Mont Terri Rock Laboratory was performed for this purpose. Several results from the work on the long-term deformation behaviour of clay-stone exist already. Nevertheless, to the author's knowledge the sound proof of a time-dependent and non-dilatant viscous deformation in the undisturbed far-field of clay-stone is still missing. Results from the rock laboratory at the Mt. Terri site yield hints for an anisotropic state of in-situ stresses, which may continue to exist in the

  14. Kinetic Study of Denatonium Sorption to Smectite Clay Minerals.

    Science.gov (United States)

    Crosson, Garry S; Sandmann, Emily

    2013-06-01

    The denatonium cation, as a benzoate salt, is the most bitter cation known to modern society and is frequently added to consumer products to reduce accidental and intentional consumption by humans and animals. Denatonium can enter the environment by accidental discharges, potentially rendering water supplies undrinkable. Interactions of denatonium with soil components ( i.e. , smectite minerals) ultimately control the environmental fate of denatonium, but the current literature is devoid of studies that evaluate denatonium sorption to smectite minerals. This study investigated the mechanism and kinetics of denatonium sorption to smectite clay minerals as a function of smectite type, temperature, pH and ionic strength. Uptake by synthetic mica montmorillonite (Syn-1), Wyoming montmorillonite (SWy-2), and Texas montmorillonite (STx-1b) at 305K was rapid, with equilibrium being reached within 2 min for all clays. Complete removal of denatonium was observed for STx-1b at pH 6.9, while partial removal was observed for Syn-1 and SWy-2. Kinetic behavior of SWy-2 and Syn-1 is consistent with a pseudo-second-order model at 305K. An activation energy of +25.9 kJ/mol was obtained for sorption to Syn-1 and was independent of temperature between 286K and 338K. Activation-free energy (Δ G *), activation enthalpy (Δ H *), and activation entropy (Δ S *) for Syn-1 were found to be +62.91 kJ/mol, +23.36 kJ/mol, and -0.130 kJ/(K·mol), respectively. Sorption capacities at pH 3.6, 6.9, and 8.2 were constant at 1.3×10 -2 g denatonium/g clay; however, the kinetic rate constant increased by 56%, going from acidic to basic solution conditions. Distribution coefficients were negatively correlated with ionic strength, suggesting cation exchange. Collectively, results suggested that smectite minerals can serve as efficient sinks for denatonium cations. This is much-needed information for agencies developing regulations regarding denatonium usage and for water treatment professionals

  15. Geosynthetic clay liners shrinkage under simulated daily thermal cycles.

    Science.gov (United States)

    Sarabadani, Hamid; Rayhani, Mohammad T

    2014-06-01

    Geosynthetic clay liners are used as part of composite liner systems in municipal solid waste landfills and other applications to restrict the escape of contaminants into the surrounding environment. This is attainable provided that the geosynthetic clay liner panels continuously cover the subsoil. Previous case histories, however, have shown that some geosynthetic clay liner panels are prone to significant shrinkage and separation when an overlying geomembrane is exposed to solar radiation. Experimental models were initiated to evaluate the potential shrinkage of different geosynthetic clay liner products placed over sand and clay subsoils, subjected to simulated daily thermal cycles (60°C for 8 hours and 22°C for 16 hours) modelling field conditions in which the liner is exposed to solar radiation. The variation of geosynthetic clay liner shrinkage was evaluated at specified times by a photogrammetry technique. The manufacturing techniques, the initial moisture content, and the aspect ratio (ratio of length to width) of the geosynthetic clay liner were found to considerably affect the shrinkage of geosynthetic clay liners. The particle size distribution of the subsoil and the associated suction at the geosynthetic clay liner-subsoil interface was also found to have significant effects on the shrinkage of the geosynthetic clay liner. © The Author(s) 2014.

  16. Comparing uranyl sorption complexes on soil and reference clays

    International Nuclear Information System (INIS)

    Chisholm-Brause, C.J.; Berg, J.M.; Conradson, S.D.; Morris, D.E.; McKinley, J.P.; Zachara, J.M.

    1993-01-01

    Clay minerals and other components in natural soils may play a key role in limiting the mobility of uranium in the environment through the formation of sorption complexes. Reference clays are frequently used as models to study sorption processes because they have well-known chemical and physical properties, but they may differ chemically and morphologically from clays derived from natural soils. Therefore, inferences based on reference clay data have been questioned. The authors have used luminescence and x-ray absorption spectroscopies to characterize the sorption complexes of aqueous uranyl (UO 2 2+ ) species on two soil smectites from the Kenoma and Ringold formations, and compared these results to those obtained on reference smectite clays. The pH dependence of uptake suggests that the ratio of sorption on amphoteric edge sites is greater for the soil smectites than for reference clays such as Wyoming montmorillonite (SWy-1). The luminescence spectra for uranyl sorbed to the soil clays are very similar to those for uranyl sorbed principally to the edge sites of SWy-1. This observation supports the solution data suggesting that adsorption to amphoteric sites is a more important mechanism for soil clays. However, the spectral data indicate that the sorption complexes on natural and reference clays are quite similar. Furthermore, as with the reference clays, the authors have found that the chemistry of the solution plays a greater role in defining the sorption complex than does the clay matrix. Thus, if differences in surface properties are adequately taken into account, the reference clays may serve as useful analogs for soil clays in investigations of metal-ion sorption

  17. Shampoo-clay heals diaper rash faster than calendula officinalis.

    Science.gov (United States)

    Adib-Hajbaghery, Mohsen; Mahmoudi, Mansoreh; Mashaiekhi, Mahdi

    2014-06-01

    Diaper rash is one of the most common skin disorders of infancy and childhood. Some studies have shown that Shampoo-clay was effective to treat chronic dermatitis. Then, it is supposed that it may be effective in diaper rash; however, no published studies were found in this regard. This study aimed to compare the effects of Shampoo-clay (S.C) and Calendula officinalis (C.O) to improve infantile diaper rash. A randomized, double blind, parallel controlled, non-inferiority trial was conducted on 60 outpatient infants referred to health care centers or pediatric clinics in Khomein city and diagnosed with diaper rash. Patients were randomly assigned into two treatment groups including S.C group (n = 30) and C.O group (n = 30) by using one to one allocation ratio. The rate of complete recovery in three days was the primary outcome. Data was collected using a checklist and analyzed using t-test, Chi-square and Fisher's exact tests and risk ratio. Totally, 93.3% of lesions in the S.C group healed in the first 6 hours, while this rate was 40% in C.O group (P < 0.001). The healing ratio for improvement in the first 6 hours was 7 times more in the S.C group. In addition, 90% of infants in the SC group and 36.7% in the C.O group were improved completely in the first 3 days (P < 0.001). S.C was effective to heal diaper rash, and also had faster effects compared to C.O.

  18. Fe(0)-clays interactions at 90°C under anoxic conditions: a comparative study between clay fraction of Callovo-Oxfordian and other purified clays

    International Nuclear Information System (INIS)

    Rivard, C.; Pelletier, M.; Villieras, F.; Barres, O.; Galmiche, M.; Ghanbaja, J.; Kohler, A.; Michau, N.

    2010-01-01

    Document available in extended abstract form only. In the context of the geological disposal of high-level radioactive waste it is of prime importance to understand the interactions between the saturated clay formation and steel containers. This can be achieved through an in-depth analysis of iron-clay interactions. Previous studies on the subject investigated the influence of solid/liquid ratio, iron/clay ratio, temperature and reaction time. The aim of the present study is to explain Callovo-Oxfordian-Fe(0) interactions by determining the role of each mineral phases present in the Callovo-Oxfordian (clay minerals, quartz, carbonates and pyrite) on the mechanisms of interaction between metal iron and clay particles. In that context, it is especially important to understand in detail the influence of clay nature and to obtain some insight about the relationships between interaction mechanisms at the molecular scale and crystallographic properties (particle size, TO or TOT layers, amount of edge faces...). The influence of the combination of different clays and the addition of other minerals must also be studied. In a first step, the Callovo-Oxfordian argillite from the Andra's underground research laboratory was purified to extract the clay fraction (illite, illite-smectite, kaolinite and chlorite). Batch experiments were carried out in anoxic conditions at 90 deg. C in the presence of background electrolyte (NaCl 0.02 M.L -1 , CaCl 2 0.04 M.L -1 ) for durations of one, three or nine months in the presence of metallic iron powder. Experiments without iron were used as control. The iron/clay ratio was fixed at 1/3 with a solid/liquid ratio of 1/20. The above mentioned experiments were also carried out in parallel on other purified clays: two smectites (Georgia bentonite and SWy2 from the Clay Minerals Society), one illite (illite du Puy) and one kaolinite (KGa2, from the Clay Minerals society). At the end of the experiments, solid and liquid phases were

  19. Studies on Tagged Clay Migration Due to Water Movement

    Energy Technology Data Exchange (ETDEWEB)

    Scharpenseel, H. W. [Institut fuer Bodenkunde der Universitaet Bonn, Federal Republic of Germany (Germany); Kerpen, W. [Arbeitsgruppe, Institut fuer Landwirtschaft der KFA Juelich, Bonn, Federal Republic of Germany (Germany)

    1967-11-15

    {sup 55}Fe-tagged clay minerals, produced by hydrothermal synthesis, serve to clarify the question whether clay migration or clay formation in situ is the predominating mechanism in the B{sub t}-development of Parabraunerde (sol brun lessive, grey brown podsolic, hapludalf, dernopodsol). They further indicate the possibilities of clay transportation caused by water percolation. Suitable experimental approaches, such as thin-layer chromatography and autoradiography, translocation tests in columns filled with monotypical textural fractions or with undisturbed soil profiles, and synchronous hydrothermal treatment of {sup 55}Fe-con raining material from different horizons of Parabraunerde, to reveal the specific readiness of the different profile zones for {sup 55}Fe-clay production, are described. The possibilities of clay percolation are discussed. (author)

  20. Studies on Tagged Clay Migration Due to Water Movement

    International Nuclear Information System (INIS)

    Scharpenseel, H.W.; Kerpen, W.

    1967-01-01

    55 Fe-tagged clay minerals, produced by hydrothermal synthesis, serve to clarify the question whether clay migration or clay formation in situ is the predominating mechanism in the B t -development of Parabraunerde (sol brun lessive, grey brown podsolic, hapludalf, dernopodsol). They further indicate the possibilities of clay transportation caused by water percolation. Suitable experimental approaches, such as thin-layer chromatography and autoradiography, translocation tests in columns filled with monotypical textural fractions or with undisturbed soil profiles, and synchronous hydrothermal treatment of 55 Fe-con raining material from different horizons of Parabraunerde, to reveal the specific readiness of the different profile zones for 55 Fe-clay production, are described. The possibilities of clay percolation are discussed. (author)

  1. Clay facial masks: physicochemical stability at different storage temperatures.

    Science.gov (United States)

    Zague, Vivian; de Almeida Silva, Diego; Baby, André Rolim; Kaneko, Telma Mary; Velasco, Maria Valéria Robles

    2007-01-01

    Clay facial masks--formulations that contain a high percentage of solids dispersed in a liquid vehicle--have become of special interest due to specific properties presented by clays, such as particle size, cooling index, high adsorption capacity, and plasticity. Although most of the physicochemical properties of clay dispersions have been studied, specific aspects concerning the physicochemical stability of clay mask products remain unclear. This work aimed at investigating the accelerated physicochemical stability of clay mask formulations stored at different temperatures. Formulations were subjected to centrifuge testing and to thermal treatment for 15 days, during which temperature was varied from -5.0 degrees to 45.0 degrees C. The apparent viscosity and visual aspect (homogeneity) of all formulations were affected by temperature variation, whereas color, odor, and pH value remained unaltered. These results, besides the estimation of physicochemical stability under aging, can be useful in determining the best storage conditions for clay-based formulations.

  2. Tensile mechanical response of polyethylene – clay nanocomposites.

    Directory of Open Access Journals (Sweden)

    2007-03-01

    Full Text Available In this work we report on the microstructural and the mechanical characteristics of high density polyethylene (HDPE-clay nanocomposites, with particular attention to the creep behaviour. The samples were prepared through melt compounding, using two high-density polyethylenes with different melt flow rate (MFR, two different organo-modified clays, and changing the relative amount of a polyethylene grafted with maleic anhydride (PEgMA compatibilizer. The intercalation process is more effective as the matrix melt viscosity decreases (higher MFR, while the clay interlamellar spacing increases as the compatibilizer amount increases. The relative stiffness of the nanocomposites increases with the addition of clay, with a limited enhancement of the relative yield stress. The better intercalation obtained by the addition of the compatibilizer is not accompanied by a concurrent improvement of the tensile mechanical properties. The creep resistance is enhanced by the introduction of clay, with an appreciable dependence on both the polyethylene and the clay type.

  3. Characterization of organophilic attapulgite clay from state of Piaui

    International Nuclear Information System (INIS)

    Silva, L.C. dos Santos; Alves, T.S.; Barbosa, R.

    2011-01-01

    The attapulgite is mineral clay typically fibrous. It owns a superficial area around 125 to 210 m²/g, cationics transfer capacity from 20 to 30 mill equivalents per 100g of clay, high capacity of sorption, considerable decolourizer capacity, chemical inertia and maintenance of thixotropics properties in the presence of electrolytes. The objective of this work was to perform the chemical modification of attapulgite original from state of Piaui - Brazil, for applications in polymeric nanocomposites. The chemical composition of clay without modification was determined by X-Ray Diffraction. The natural clay and organophilizated one were characterized by X-Ray Diffraction (XRD), by Fourier Transform Infra-Red spectroscopy (FTIR), and Foster's swelling. The obtained results indicated the presence of characteristics groups of the salt in the clay, alteration in its chemical composition, evidencing that the chemical modification in the clay was efficient, could the same be applied in preparation of polymeric nanocomposites. (author)

  4. Effects of feeding bentonite clay upon ochratoxin A-induced immunosuppression in broiler chicks.

    Science.gov (United States)

    Khatoon, Aisha; Khan, Muhammad Zargham; Abidin, Zain Ul; Bhatti, Sheraz Ahmed

    2018-03-01

    A presence of mycotoxins in feed is one of the most alarming issues in the poultry feed industry. Ochratoxins, produced by several Aspergillus and Penicillium species, are important mycotoxin regarding the health status of poultry birds. Ochratoxins are further classified into to several subtypes (A, B, C, etc) depending on their chemical structures, but ochratoxin A (OTA) is considered the most important and toxic. Bentonite clay, belonging to phyllosilicates and formed from weathering of volcanic ashes, has adsorbent ability for several mycotoxins. The present study was designed to study the effects of bentonite clay upon OTA-induced immunosuppression in broiler chicks. For this, 480 day-old broiler chicks were procured from a local hatchery and then different combinations of OTA (0.15, 0.3, or 1.0 mg/kg) and bentonite clay (5, 10, and 20 g/kg) were incorporated into their feed. At 13, 30, and 42 days of age, parameters such as antibody responses to sheep red blood cells, in situ lymphoproliferative responses to mitogen (PHA-P), and in situ phagocytic activity (i.e., via carbon clearance) were determined respectively. The results indicated there was a significant reduction of total antibody and immunoglobulin titres, lymphoproliferative responses, and phagocytic potential in OTA-treated birds, suggesting clear immunosuppression by OTA in birds in a dose-dependent manner. These results were also significantly lower in all combination groups (OTA with bentonite clay), suggesting few to no effects of feeding bentonite clay upon OTA- induced alterations in different immune parameters.

  5. Protocol for characterization of clay as a backfill and coverage layers for surface repository

    International Nuclear Information System (INIS)

    Santos, Daisy M.M.; Tello, Clédola C.O.

    2017-01-01

    The Radioactive Waste Management includes the operations since generation of the waste until its storage in repository, ensuring the protection of human beings and the environment from the possible negative impacts. The radioactive waste is segregated, treated, conditioned in suitable packages for posterior storage or disposal in repository. The 'RBMN Project' objective is to implement the repository for the disposal of low and intermediate level radioactive wastes generated by nuclear activities in Brazil, proposing a definitive solution for their storage. Engineered and natural barriers as the backfill and coverage layers will compose the disposal system of a near surface repository, concept proposed by the 'RBMN Project'. The use of these barriers aims to avoid or restrict the release of radionuclides from the waste to the human beings and environment. The waterproofing barriers are composed of clays. Certainly, for the national repository, will be used those clays existing in the place where it will be constructed. Them some basic tests will have to be carried out to verify the suitability of these clays as barriers. These tests were determined and performed with reference clay, a Brazilian bentonite constituted of 67.2% montmorillonite. The results were compared with national and international literature of materials with similar mineralogical features. The values found with 95% of confidence interval were 9.73±0,35 μm for granulometric size; 13,3±0,6% for the moisture content and 816±9 mmol.kg -1 for the capacity of cationic exchange. A protocol for characterization of clay was elaborated presenting these tests for it future use. (author)

  6. Protocol for characterization of clay as a backfill and coverage layers for surface repository

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Daisy M.M.; Tello, Clédola C.O., E-mail: marymarchezini@gmail.com, E-mail: tellocc@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    The Radioactive Waste Management includes the operations since generation of the waste until its storage in repository, ensuring the protection of human beings and the environment from the possible negative impacts. The radioactive waste is segregated, treated, conditioned in suitable packages for posterior storage or disposal in repository. The 'RBMN Project' objective is to implement the repository for the disposal of low and intermediate level radioactive wastes generated by nuclear activities in Brazil, proposing a definitive solution for their storage. Engineered and natural barriers as the backfill and coverage layers will compose the disposal system of a near surface repository, concept proposed by the 'RBMN Project'. The use of these barriers aims to avoid or restrict the release of radionuclides from the waste to the human beings and environment. The waterproofing barriers are composed of clays. Certainly, for the national repository, will be used those clays existing in the place where it will be constructed. Them some basic tests will have to be carried out to verify the suitability of these clays as barriers. These tests were determined and performed with reference clay, a Brazilian bentonite constituted of 67.2% montmorillonite. The results were compared with national and international literature of materials with similar mineralogical features. The values found with 95% of confidence interval were 9.73±0,35 μm for granulometric size; 13,3±0,6% for the moisture content and 816±9 mmol.kg{sup -1} for the capacity of cationic exchange. A protocol for characterization of clay was elaborated presenting these tests for it future use. (author)

  7. Tricky Treats

    Centers for Disease Control (CDC) Podcasts

    The Eagle Books are a series of four books that are brought to life by wise animal characters - Mr. Eagle, Miss Rabbit, and Coyote - who engage Rain That Dances and his young friends in the joy of physical activity, eating healthy foods, and learning from their elders about health and diabetes prevention. Tricky Treats shows children the difference between healthy snacks and sweet treats.

  8. Uranyl adsorption at clay mineral surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Roesch, N. [Technische Univ. Muenchen (Germany). Fachgebiet Theoretische Chemie

    2016-11-01

    This first systematic survey of actinide adsorption at complex clay mineral surfaces, which provided new insights at the atomic level, is currently being extended to neptunyl NpO{sub 2}{sup +} and more complex minerals, like iron-substituted phyllosilicates. In this way we examine if the concepts developed so far can be applied more generally to support the interpretation of pertinent experiments. A further facet of these studies is to account also for the dynamic nature of the mineral/water interface by means of exemplary dynamic simulations.

  9. Electrochemical remediation of copper contaminated clay soils

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, V.A.; Babakina, O.A.; Mitojan, R.A. [Moscow State Univ. (Russian Federation)

    2001-07-01

    The study objective focused on electrochemical remediation copper polluted soils in the presence of adjuvant substances and conditions that are more effective for the treatment. Some of these substances were studied in different researches. Moreover, authors obtained a result of extraction copper rate higher than 90%. In this connection the following problems were set: - Influence organic and inorganic substances on copper mobility in soil under the DC current. - Moisture effect on copper migration in clay. - Electrochemical remediation soils different mineralogical composition. - A washing conditions contribution to electrochemical remediation of soil from copper. - Accuracy rating experimental dates. (orig.)

  10. Clay Ceramic Filter for Water Treatment

    Directory of Open Access Journals (Sweden)

    Zereffa Enyew Amare

    2017-05-01

    Full Text Available Ceramic water filters were prepared from different proportions of kaolin and soft wood and sintered at 900 °C, 950 °C, and 1000 °C. The flow rate, conductivity, pH of filtered water and removal efficiency (microbial, water hardness agent’s, nitrite and turbidity were analysed. The ceramic filter with 15 % saw dust, 80 % clay and 5 % grog that was fired at temperature of 950 °C or 1000 °C showed the best removal efficiency. Statistical ANOVA tests showed a significant difference between ceramic filters with various compositions in their removal efficiencies.

  11. Production of polyol carbonates and their intercalation into Smectite clays

    OpenAIRE

    Shaheen, Uzma

    2017-01-01

    In hyper-saline conditions, clays in geosynthetic clay liners contract and fail to form a hydraulic barrier due to removal of water from the interlayer spaces of smectite, which is the swelling mineral component of bentonites used in geosynthetic clay liners. Five-membered cyclic carbonates such as propylene carbonate have been reported to form stable intercalated complexes with hydrated Na-smectite, which maintain swollen states at 1M). Glycerol carbonate was selected as an alternative c...

  12. Electrokinetic enhancement of phenanthrene biodegradation in creosote-polluted clay soil

    International Nuclear Information System (INIS)

    Niqui-Arroyo, Jose-Luis; Bueno-Montes, Marisa; Posada-Baquero, Rosa; Ortega-Calvo, Jose-Julio

    2006-01-01

    Given the difficulties caused by low-permeable soils in bioremediation, a new electrokinetic technology is proposed, based on laboratory results with phenanthrene, to afford bioremediation of polycyclic aromatic hydrocarbons (PAH) in clay soils. Microbial activity in a clay soil historically polluted with creosote was promoted using a specially designed electrokinetic cell with a permanent anode-to-cathode flow and controlled pH. The rates of phenanthrene losses during treatment were tenfold higher in soil treated with an electric field than in the control cells without current or microbial activity. Results from experiments with Tenax-assisted desorption and mineralization of 14 C-labeled phenanthrene indicated that phenanthrene biodegradation was limited by mass-transfer of the chemical. We suggest that the enhancement effect of the applied electric field on phenanthrene biodegradation resulted from mobilization of the PAH and nutrients dissolved in the soil fluids. - Electrokinetic bioremediation is a potentially effective technology to treat PAH-polluted, clay-rich soils

  13. Admixing dredged marine clay with cement-bentonite for reduction of compressibility

    Science.gov (United States)

    Rahilman, Nur Nazihah Nur; Chan, Chee-Ming

    2017-11-01

    Cement-based solidification/stabilization is a method that is widely used for the treatment of dredged marine clay. The key objective for solidification/stabilization is to improve the engineering properties of the originally soft, weak material. Dredged materials are normally low in shear strength and bearing capacity while high incompressibility. In order to improve the material's properties for possible reuse, a study on the one-dimensional compressibility of lightly solidified dredged marine clay admixed with bentonite was conducted. On the other hand, due to the viscous nature, particularly the swelling property, bentonite is a popular volumising agent for backfills. In the present study, standard oedometer test was carried out to examine the compressibility of the treated sample. Complementary strength measurements were also conducted with laboratory vane shear setup on both the untreated and treated dredged marine clay. The results showed that at the same binder content, the addition of bentonite contributed significantly to the reduction of compressibility and rise in undrained shear strength. These improved properties made the otherwise discarded dredged marine soils potentially reusable for reclamation works, for instance.

  14. Microstructures and physical properties of "backfill" clays: comparison of residua and sedimentary montmorillonite clays

    Czech Academy of Sciences Publication Activity Database

    Přikryl, R.; Ryndová, T.; Boháč, J.; Weishauptová, Zuzana

    2003-01-01

    Roč. 23, 1-4 (2003), s. 149-156 ISSN 0169-1317 R&D Projects: GA AV ČR IAA2046101 Institutional research plan: CEZ:AV0Z3046908 Keywords : bentonite * montmorillonite-rich clay * hydrophysical properties Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.287, year: 2003

  15. Clay exfoliation and polymer/clay aerogels by supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    Simona eLongo

    2013-11-01

    Full Text Available Supercritical carbon dioxide (scCO2 treatments of a montmorillonite (MMT intercalated with ammonium cations bearing two long hydrocarbon tails (organo-modified MMT, OMMT led to OMMT exfoliation, with loss of the long-range order in the packing of the hydrocarbon tails and maintenance of the long-range order in the clay layers. The intercalated and the derived exfoliated OMMT have been deeply characterized, mainly by X-ray diffraction analyses. Monolithic composite aerogels, with large amounts of both intercalated and exfoliated OMMT and including the nanoporous-crystalline δ form of syndiotactic polystyrene (s-PS, have been prepared, by scCO2 extractions of s-PS-based gels. Also for high OMMT content, the gel and aerogel preparation procedures occur without re-aggregation of the exfoliated clay, which is instead observed for other kinds of polymer processing. Aerogels with the exfoliated OMMT have more even dispersion of the clay layers, higher elastic modulus and larger surface area than aerogels with the intercalated OMMT. Extremely light materials with relevant transport properties could be prepared. Moreover, s-PS-based aerogels with exfoliated OMMT could be helpful for the handling of exfoliated clay minerals.

  16. Diffusion, sorption and stability of radionuclide-organic complexes in clays and clay-organic complexes

    International Nuclear Information System (INIS)

    Staunton, S.; Rees, L.V.C.

    1991-01-01

    The dependence on various parameters of the diffusion coefficient of neptunium (V) in clay systems has been studied. The effect of the clay mineralogy, the charge compensating cation in the clay, the ionic strength of a background perchlorate solution and the presence of three organic ligands have been investigated. The diffusion coefficients were compared to those predicted if diffusion occurred only in the liquid phase and adsorption was reversible; agreement was fairly good. An approximation to the diffusion coefficient can thus be obtained from readily measured experimental parameters. There is no evidence of surface phase diffusion. The most significant factor in determining the diffusion coefficient is the magnitude of the distribution ratio, itself highly dependent on the nature of the clay. Neither EDTA nor citrate modified the diffusion coefficient. Although the presence of 1 or 100 mg dm -3 of Aldrich humic acid had little effect on the distribution ratio of neptunium, it caused a lowering of the measured diffusion coefficient. This is interpreted in terms of the limiting liquid phase diffusion coefficient and the true liquid phase impedance factor of neptunium-humic acid complexes. 21 figs; 3 tabs; 20 refs

  17. Recent advances in clay mineral-containing nanocomposite hydrogels.

    Science.gov (United States)

    Zhao, Li Zhi; Zhou, Chun Hui; Wang, Jing; Tong, Dong Shen; Yu, Wei Hua; Wang, Hao

    2015-12-28

    Clay mineral-containing nanocomposite hydrogels have been proven to have exceptional composition, properties, and applications, and consequently have attracted a significant amount of research effort over the past few years. The objective of this paper is to summarize and evaluate scientific advances in clay mineral-containing nanocomposite hydrogels in terms of their specific preparation, formation mechanisms, properties, and applications, and to identify the prevailing challenges and future directions in the field. The state-of-the-art of existing technologies and insights into the exfoliation of layered clay minerals, in particular montmorillonite and LAPONITE®, are discussed first. The formation and structural characteristics of polymer/clay nanocomposite hydrogels made from in situ free radical polymerization, supramolecular assembly, and freezing-thawing cycles are then examined. Studies indicate that additional hydrogen bonding, electrostatic interactions, coordination bonds, hydrophobic interaction, and even covalent bonds could occur between the clay mineral nanoplatelets and polymer chains, thereby leading to the formation of unique three-dimensional networks. Accordingly, the hydrogels exhibit exceptional optical and mechanical properties, swelling-deswelling behavior, and stimuli-responsiveness, reflecting the remarkable effects of clay minerals. With the pivotal roles of clay minerals in clay mineral-containing nanocomposite hydrogels, the nanocomposite hydrogels possess great potential as superabsorbents, drug vehicles, tissue scaffolds, wound dressing, and biosensors. Future studies should lay emphasis on the formation mechanisms with in-depth insights into interfacial interactions, the tactical functionalization of clay minerals and polymers for desired properties, and expanding of their applications.

  18. Quorum Sensing Disruption in Vibrio harveyi Bacteria by Clay Materials.

    Science.gov (United States)

    Naik, Sajo P; Scholin, Jonathon; Ching, San; Chi, Fang; Herpfer, Marc

    2018-01-10

    This work describes the use of clay minerals as catalysts for the degradation of quorum sensing molecule N-(3-oxooctanoyl)-dl-homoserine lactone. Certain clay minerals as a result of their surface properties and porosity can catalytically degrade the quorum sensing molecule into smaller fragments. The disruption of quorum sensing by clay in a growing Gram-negative Vibrio harveyi bacteria culture was also studied by monitoring luminescence and population density of the bacteria, wherein quenching of bacterial quorum sensing activity was observed by means of luminescence reduction. The results of this study show that food-grade clays can be used as biocatalysts in disrupting bacterial activity in various media.

  19. Water diffusion in clays with added organic surfactants

    International Nuclear Information System (INIS)

    Pineda-Pinon, J; Mendoza-Lopez, M L; Manzano-RamIrez, A; Perez-Robles, J F; Vega-Duran, J T

    2007-01-01

    Tensoactive agents may decrease water absorption in clay products like adobes. They modify the characteristics of the surface of clay particles. Characterization of water diffusion through the pores of modified clays is important to apply appropriate surface modifiers and to improve their performance. We established a simple model for water diffusion in test samples of defined dimensions to estimate real physical parameters and their effect on water absorption. Adsorption mechanisms are examined based on experimental results. The fitting of the experimental data to the model provides a deep understanding of water adsorption in chemically modified clays. A better agreement between the model and the experimental data is achieved for complex molecules

  20. Development of polymer nanocomposites with regional bentonite clay

    International Nuclear Information System (INIS)

    Araujo, Edcleide M.; Leite, Amanda M.D.; Paz, Rene A. da; Medeiros, Keila M. de; Melo, Tomas J.A.; Barbosa, Josiane D.V.; Barbosa, Renata

    2011-01-01

    nanocomposites with regional bentonite clay were prepared by melt intercalation technique. The clays were studied without modification and modified with four quaternary ammonium salts. It was evidenced by X-ray diffraction that salts were incorporated into the clay structure thus confirming its organophilization. The nanocomposites were evaluated by means of thermal mechanic and flammability tests where presented properties significantly improved their pure polymers. The process of biodegradation of obtained bio nanocomposites was accelerated by the presence of clay. The produced membranes from nanocomposites have potential in the oil-water separation. (author)

  1. The use of clays as sorbents and catalysts

    International Nuclear Information System (INIS)

    McCabe, R.W.

    1998-01-01

    The paper attempts to show the structural, physical and chemical properties of clay minerals relate to their laboratory, industrial and environmental uses as sorbents and catalysts. A brief review of the formulae and structures of clays and their relationship to their chemical and physical properties follows. Clay minerals are also useful in environmental protection as they can adsorb crude oils from spills and they are used, sometimes mixed into concrete, as containment barriers for radionuclides caesium 137 and strontium 90. Clay soils can also act as natural barriers to the migration of radionuclides in the environment

  2. Rheology of Poly(N-isopropylacrylamide)-Clay Nanocomposite Hydrogels

    Science.gov (United States)

    Lombardi, Jack; Xu, Di; Bhatnagar, Divya; Gersappe, Dilip; Sokolov, Jonathan; Rafailovich, Miriam

    2015-03-01

    The stiffness of PNIPA Gels has been reported could be significant improved by gelation with clay fillers. Here we conducted systematic rheology study of synthesized PNIPA-Clay Composites at different clay concentration, in a range from fluid to strong gel, where G'' dominant changed to G' dominant. Molecular dynamics simulation was employed to analyze the structure of composites and corresponding mechanical changes with increased clays. Where we found viscoelastic behavior become significant only 1.5 times above percolation threshold. The yield stress extrapolated from our rheology results shows good fitting to modified Mooney's theory of suspension viscosity.

  3. Clays and Clay Minerals and their environmental application in Food Technology

    Science.gov (United States)

    del Hoyo Martínez, Carmen; Cuéllar Antequera, Jorge; Sánchez Escribano, Vicente; Solange Lozano García, Marina; Cutillas Díez, Raul

    2013-04-01

    The clay materials have led to numerous applications in the field of public health (del Hoyo, 2007; Volzone, 2007) having been demonstrated its effectiveness as adsorbents of all contaminants. Some biodegradable materials are used for for adsorption of chemical contaminants: lignins (Valderrabano et al., 2008) and also clays and clay minerals, whose colloidal properties, ease of generating structural changes, abundance in nature, and low cost make them very suitable for this kind of applications. Among the strategies used at present to preserve the quality of the water and this way to diminish the environmental risk that supposes the chemical pollution, stands out the use of adsorbents of under cost, already they are natural or modified, to immobilize these compounds and to avoid the pollution of the water with the consequent reduction of environmental and economic costs Thanks to the development of the science and the technology of the nourishment in the last 50 years, there have revealed itself several new substances that can fulfill beneficial functions in the food, and these substances, named food additives, are today within reach of all. The food additives recover a very important role in the complex nourishing supply. The additives fulfill several useful functions in the food, which often we give for sat. Nevertheless the widespread use of food additives in the food production also influences the public health. The food industries, which are very important for the economy, spill residues proved from its activity that they have to be controlled to evaluate the environmental impact and to offer the necessary information about the quantitative evaluation of the chemical risk of the use of food additives for the public health. We have studied the adsorption of several contaminants by natural or modified clays, searching their interaction mechanisms and the possible recycling of these materials for environmental purposes and prevention of the health. References

  4. Clay shale as host rock. A geomechanical contribution about Opalinus clay

    International Nuclear Information System (INIS)

    Lempp, Christof; Menezes, Flora; Sachwitz, Simon

    2016-01-01

    The Opalinuston is a prominent rock representing the type of organic clay shales or clay stones within the sequence of Triassic and Jurassic marine sediments in Southern Germany. The rock forms a homogenous unit some ten meters thick. The degree of consolidation of this type of pelitic rock depends mainly on the former load conditions, but is also dependent on the long-term weathering and even on the present exposition. The geomechanical parameters such as shear strength, tensional strength and permeability vary with the state of consolidation and become important when the use is discussed of such rocks for radioactive waste disposal. A tunneling project at the northern escarpment of the Swabian Alb (Southwest Germany) within the Opalinus clay offered the rare opportunity to obtain fresh unweathered rock samples in greater amounts compared to fresh drilling cores from which geomechanical investigations are usually undertaken. Consequently, the results of geomechanical laboratory testings are presented in order to compare here the results of multistep triaxial compression tests, of hydraulic fracturing laboratory tests and of some other tests for rock characterization with the corresponding results of Opalinus clay sites in Switzerland that were investigated by the Swiss Nagra Company for host rock characterization. After a discussion of the relevant state of fresh Opalinus clay, especially of suction pressure conditions and saturation state, the results of triaxial shear tests are presented. Increasing shear deformation at increasing pressure and unchanged water saturation do not result in a significant strength reduction of the Opalinus clay. The rock shows increasing cohesion and stiffness, if multiple loading has repeatedly reached the failure point. Thus there is no increased permeability with continued shearing. Only at the beginning of the shearing process is a temporarily increased permeability to be expected due to dilatation processes. An increased

  5. Orientation and the extent of exfoliation of clay on scratch damage in polyamide 6 nanocomposites

    International Nuclear Information System (INIS)

    Dasari, Aravind; Yu Zhongzhen; Mai Yiuwing; Kim, Jang-Kyo

    2008-01-01

    The major objectives of this work are to understand the effects of organoclay, its extent of exfoliation and orientation, and indenter geometry on the scratch characteristics of polyamide 6/organoclay nanocomposites. Two different organically treated clays are used for this purpose and their structural parameters in a polyamide 6 matrix quantified. It is shown that, while the material properties are important for scratching resistance, they are not the only determinants of the scratch performance of materials. Further, despite proving beneficial to scratch resistance, in terms of residual depth, the presence (and exfoliation) of organoclay promotes the formation of brittle cracks during scratching. But with no organoclay layers, plastic flow controls the scratch damage in neat polyamide 6 with large residual depths. Factors such as orientation of clay layers and variations of indenter tip geometry also exert dominant effects on scratch penetration resistance and damage. Additionally, significant plastic flow and rotation of organoclay layers from the original configuration are observed underneath the sliding indenter

  6. Physicochemical properties and oxidative stability of bleached pomace-olive oil on Tunisian activated clays

    International Nuclear Information System (INIS)

    Jahouach, Wafa

    2002-01-01

    This work is a contribution to studying bleaching process, which is an important stage in refining of vegetable oils. This process permitted to reduce or convert undesired constituents to harmless ones from oils and fats. Virgin olive oil, considered as reference, and pomace-olive oil were bleached in optimal conditions using Tunisian activated clays ( collected from the South of Tunisia) which were prepared in our laboratory and compared with commercial bleaching earths. It was shown that activated Tunisian clays are characterized by a very important adsorptive capacity, which is similar to that of commercial ones. In addition, the study of physicochemical properties of bleached oils was considered. The fatty acid composition (GC), the triacylglycerol composition (HPLC), and oxidative stability (UV spectrometry) allowed to conclude that treated oils do not undergo considerable physicochemical alterations and their caracteristics remain in concordance with international standards relative to edible refined oils. (Author)

  7. Using the direct method in organophilization of clay chocolate 'A' with organic surfactant

    International Nuclear Information System (INIS)

    Patricio, A.C.L.; Sousa, A.B.; Silva, M.M. da; Rodrigues, M.G.F.; Laborde, H.M.

    2012-01-01

    During the development of this work, we studied the preparation of organoclays through direct method, starting from the natural clay Chocolate 'A' using the quaternary ammonium salt, chloride, alkyl dimethyl benzyl ammonium (Dodigen). The samples were characterized by X-Ray Diffraction (XRD), Infrared Spectroscopy in the Region (IV), Gravimetric and Differential Thermal Analysis (DTA / TGA) and swelling of Foster using solvents, gasoline, kerosene and diesel. Was observed by the results XRD, IR and DTA / TG effective intercalation of quaternary ammonium salts of the inter lamellar spaces of the clay, and by Foster swelling test samples treated with the quaternary ammonium salt Dodigen showed affinity for all the solvents tested. (author)

  8. Behavior of clay materials under ionizing radiation

    International Nuclear Information System (INIS)

    Laine, Maxime

    2017-01-01

    The aim of this PhD thesis is to study and understand, by proposing reaction mechanisms, the behavior under irradiation of various clay materials. The systems of interest were first synthetic talc, which is the prototype of a non-swelling material. Under irradiation by accelerated electrons, the production of dihydrogen in this system, due solely to surface hydroxyl groups, is of the same order of magnitude as the one obtained in liquid water. This yield is divided by 30 in the case of natural talc from Luzenac, thus highlighting the importance of the impurities as scavengers of the precursors of dihydrogen. Synthetic smectites, which are swelling materials, were then studied. The results evidence the radiolysis of water confined in the interlayer space, leading to H 2 yields which may be two to three times higher than those measured in water. Moreover, they are similar for montmorillonite and saponite, evidencing that the charge location plays only a minor role. Finally, the study of double layered hydroxides or anionic clays shows that, in this case, the nature of the anion in the inter lamellar space controls the reactivity. Parallel to these measurements, electron paramagnetic spectroscopy experiments have enabled proposing reaction mechanisms. Finally, all these results are of interest in the context of the disposal of radioactive waste. (author) [fr

  9. Halloysite Clay Nanotubes for Enzyme Immobilization.

    Science.gov (United States)

    Tully, Joshua; Yendluri, Raghuvara; Lvov, Yuri

    2016-02-08

    Halloysite clay is an aluminosilicate nanotube formed by rolling flat sheets of kaolinite clay. They have a 15 nm lumen, 50-70 nm external diameter, length of 0.5-1 μm, and different inside/outside chemistry. Due to these nanoscale properties, they are used for loading, storage, and controlled release of active chemical agents, including anticorrosions, biocides, and drugs. We studied the immobilization in halloysite of laccase, glucose oxidase, and lipase. Overall, negatively charged proteins taken above their isoelectric points were mostly loaded into the positively charged tube's lumen. Typical tube loading with proteins was 6-7 wt % from which one-third was released in 5-10 h and the other two-thirds remained, providing enhanced biocatalysis in nanoconfined conditions. Immobilized lipase showed enhanced stability at acidic pH, and the optimum pH shifted to more alkaline pH. Immobilized laccase was more stable with respect to time, and immobilized glucose oxidase showed retention of enzymatic activity up to 70 °C, whereas the native sample was inactive.

  10. Halloysite nanotubule clay for efficient water purification.

    Science.gov (United States)

    Zhao, Yafei; Abdullayev, Elshad; Vasiliev, Alexandre; Lvov, Yuri

    2013-09-15

    Halloysite clay has chemical structure similar to kaolinite but it is rolled in tubes with diameter of 50 nm and length of ca. 1000 nm. Halloysite exhibits higher adsorption capacity for both cationic and anionic dyes because it has negative SiO2 outermost and positive Al2O3 inner lumen surface; therefore, these clay nanotubes have efficient bivalent adsorbancy. An adsorption study using cationic Rhodamine 6G and anionic Chrome azurol S has shown approximately two times better dye removal for halloysite as compared to kaolin. Halloysite filters have been effectively regenerated up to 50 times by burning the adsorbed dyes. Overall removal efficiency of anionic Chrome azurol S exceeded 99.9% for 5th regeneration cycle of halloysite. Chrome azurol S adsorption capacity decreases with the increase of ionic strength, temperature and pH. For cationic Rhodamine 6G, higher ionic strength, temperature and initial solution concentration were favorable to enhanced adsorption with optimal pH 8. The equilibrium adsorption data were described by Langmuir and Freundlich isotherms. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Geotechnical and mineralological Konyaalti (Antalya, Turkey) clays

    International Nuclear Information System (INIS)

    Acar, Mustafa Hilami; Uzer, A.U.; Altunsoy, M.

    2008-01-01

    Geotechnical and mineralogical characteristics of blue-green clays of the Harbour District existing inside the boundaries of Antalya Konyaalti Municipality were investigated with comprehensive field and laboratory tests. Today, building construction in this district is carried out without any prior qualified geotechnical investigations taking place. Undisturbed and disturbed soil specimens were taken from 12 drilled boreholes at 1.5 m intervals and down 30 m deep. Shelby tubes samples were retrieved and SPT were carried out in order to determine soil profile and geotechnical properties. After comparing the laboratory and field test results, it was observed that they were in agreement. Strength and compressibility characteristics of the soil were defined with the correlations using laboratory and field test results. Since the region has been formed of lagoon-sedimented clays, rock analysis was done on two specimens achieved from various depths along the soil profile. XRD analyses on eleven specimens were also conducted. Unconfined compressive strength (qu), undrained cohesion (Cu) and compression index (Cc) varies between 40 kN/m2, 7.0 kN/m2 and 90 kN/m2, 0.095 and 0.38, respectively. (author)

  12. Kaolinitic clay-based grouting demonstration

    International Nuclear Information System (INIS)

    McCloskey, A.L.; Barry, C.J.; Wilmoth, R.

    1997-01-01

    An innovative Kaolinitic Clay-Based Grouting Demonstration was performed under the Mine Waste Technology Program (MWTP), funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by the EPA and the U.S. Department of Energy (DOE). The objective of the technology was to demonstrate the effectiveness of kaolinitic clay-based grouting in reducing/eliminating infiltration of surface and shallow groundwater through fractured bedrock into underground mine workings. In 1993, the Mike Horse Mine was selected as a demonstration site for the field implementation and evaluation of the grouting technology. The mine portal discharge ranged between 114 to 454 liters per minute (30 to 120 gpm) of water containing iron, zinc, manganese, and cadmium at levels exceeding the National Drinking Water Maximum Contaminant Levels. The grout formulation was designed by the developer Morrison Knudsen Corporation/Spetstamponazhgeologia (MK/STG), in May 1994. Grout injection was performed by Hayward Baker, Inc. under the directive of MSE Technology Applications, Inc. (MSE-TA) during fall of 1994. The grout was injected into directionally-drilled grout holes to form a grout curtain at the project site. Post grout observations suggest the grout was successful in reducing the infiltration of the surface and shallow groundwater from entering the underground mine workings. The proceeding paper describes the demonstration and technology used to form the subsurface barrier in the fracture system

  13. Quantum-chemical modeling of smectite clays

    Science.gov (United States)

    Aronowitz, S.; Coyne, L.; Lawless, J.; Rishpon, J.

    1982-01-01

    A self-consistent charge extended Hueckel program is used in modeling isomorphic substitution of Al(3+) by Na(+), K(+), Mg(2+), Fe(2+), and Fe(3+) in the octahedral layer of a dioctahedral smectite clay, such as montmorillonite. Upon comparison of the energies involved in the isomorphic substitution, it is found that the order for successful substitution is as follows: Al(3+), Fe(3+), Mg(2+), Fe(2+), Na(+), which is equivalent to Ca(2+), and then K(+). This ordering is found to be consistent with experimental observation. The calculations also make it possible to determine the possible penetration of metal ions into the clay's 2:1 crystalline layer. For the cases studied, this type of penetration can occur at elevated temperatures into regions where isomorphic substitution has occurred with metal ions that bear a formal charge of less than 3+. The computed behavior of the electronic structure in the presence of isomorphic substitution is found to be similar to behavior associated with semiconductors.

  14. Organically modified clay removes oil from water

    International Nuclear Information System (INIS)

    Alther, G.R.

    1995-01-01

    When bentonite or other clays and zeolite are modified with quaternary amines, they become organophilic. Such modified bentonites are used to remove mechanically emulsified oil and grease, and other sparingly soluble organics. Types of oil found in water can include fats, lubricants, cutting fluids, heavy hydrocarbons such as tars, grease, crude oil, diesel oils; and light hydrocarbons such as kerosene, jet fuel, and gasoline. If the organoclay is granulated, it is placed into a liquid phase carbon filter vessel to remove FOGs (Free Oil and Grease) and chlorinated hydrocarbons. In this application the clay is mixed with anthrazite to prevent early plugging of the filter by oil or grease droplets. In batch systems a powdered organoclay is employed. Organoclay removes mechanically emulsified oil and grease at 5--7 times the rate of activated carbon, or 50% of its dry weight. Oil and grease and other large sparingly soluble chlorinated hydrocarbons and NOMs (Natural Organic Matter) blind the pores of activated carbon (and ion-exchange resins), reducing its effectiveness significantly. It is therefore economically advantageous for the end user to prepolish the water before it enters carbon vessels. Operating costs can often be reduced by 50% or more

  15. Geosynthetic clay liners - slope stability field study

    International Nuclear Information System (INIS)

    Carson, D.A.; Daniel, D.E.; Koerner, R.M.; Bonaparte, R.

    1997-01-01

    A field research project was developed to examine the internal shear performance of geosynthetic clay liners (GCLs). Several combinations of cross sections were assembled using GCL materials that were available at the time of project initiation. The cross sections utilized were intended to simulate landfill cover applications. Thirteen (13) resulting test plots were constructed on two different slope angles, and each plot is instrumented for physical displacement and soil moisture characteristics. Test plots were constructed in a manner that dictated the shear plane in the clay portion of the GCL product. The project purpose is to assess field performance and to verify design parameters associated with the application of GCLs in waste containment applications. Interim research data shows that test slopes on 2H:1V show global deformation, but little internal shear evidence, and the 3H:1V slopes show little deformation at approximately 650 days. The research is ongoing, and this paper presents the most recent information available from the project

  16. Thermal conductivity of unsaturated clay-rocks

    Directory of Open Access Journals (Sweden)

    D. Jougnot

    2010-01-01

    Full Text Available The parameters used to describe the electrical conductivity of a porous material can be used to describe also its thermal conductivity. A new relationship is developed to connect the thermal conductivity of an unsaturated porous material to the thermal conductivity of the different phases of the composite, and two electrical parameters called the first and second Archie's exponents. A good agreement is obtained between the new model and thermal conductivity measurements performed using packs of glass beads and core samples of the Callovo-Oxfordian clay-rocks at different saturations of the water phase. We showed that the three model parameters optimised to fit the new model against experimental data (namely the thermal conductivity of the solid phase and the two Archie's exponents are consistent with independent estimates. We also observed that the anisotropy of the effective thermal conductivity of the Callovo-Oxfordian clay-rock was mainly due to the anisotropy of the thermal conductivity of the solid phase.

  17. Optimization of lining design in deep clays

    International Nuclear Information System (INIS)

    Rousset, G.; Bublitz, D.

    1989-01-01

    The main features of the mechanical behaviour of deep clay are time dependent effects and also the existence of a long term cohesion which may be taken into account for dimensioning galleries. In this text, a lining optimization test is presented. It concerns a gallery driven in deep clay, 230 m. deep, at Mol (Belgium). We show that sliding rib lining gives both: - an optimal tunnel face advance speed, a minimal closure of the gallery wall before setting the lining and therefore less likelihood of failure developing inside the rock mass. - limitation of the length of the non-lined part of the gallery. The chosen process allows on one hand the preservation of the rock mass integrity, and, on the other, use of the confinement effect to allow closure under high average stress conditions; this process can be considered as an optimal application of the convergence-confinement method. An important set of measurement devices is then presented along with results obtained for one year's operation. We show in particular that stress distribution in the lining is homogeneous and that the sliding limit can be measured with high precision

  18. Study of strontium sorption in Brazilian clays for their use as a barrier in repository of radioactive wastes

    International Nuclear Information System (INIS)

    Freire, Carolina Braccini; Tello, Cledola Cassia Oliveira de

    2008-01-01

    Wastes in general should be properly treated and stored. The the radioactive wastes also require suitable and safe management beginning in their generation until the storage in repository. The objective of this research was to characterize some Brazilian clays in order to evaluate the viability of their use in the backfill layer, one of the radioactive waste repository barriers. The main function of this barrier is to contribute in the delay of the radionuclides movement, and to prevent their release into the environment. Four clays provided by national suppliers were selected for the research: Ca-Bentonite (Dol 01), Na-Bentonite (Dol 02), Kaolinite (Ind 01) and Vermiculite (Ubm 04.) Their physical, chemical and mineralogical characteristics were determined, and also their sorption potential of Strontium cation. It was confirmed through theses results a direct relationship among their specific surface (SS), the capacity of cationic exchange (CCE) and pH. The CCE results followed this increasing order: Ind 01, Dol 01, and Dol 02. In accordance with the models of Freundlich (K f ) and Langmuir (M), the clays Dol 01 and Dol 02 were the best sorbers of Sr 2+ . The Gibbs free energy change (ΔG deg) was calculated for the sorption reactions between the clays and the cations, and it was negative for all clays, confirming the sorption reaction spontaneity. (author)

  19. Surface modification of montmorillonite on surface Acid-base characteristics of clay and thermal stability of epoxy/clay nanocomposites.

    Science.gov (United States)

    Park, Soo-Jin; Seo, Dong-Il; Lee, Jae-Rock

    2002-07-01

    In this work, the effect of surface treatments on smectitic clay was investigated in surface energetics and thermal behaviors of epoxy/clay nanocomposites. The pH values, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the effect of cation exchange on clay surface and the exfoliation phenomenon of clay interlayer. The surface energetics of clay and thermal properties of epoxy/clay nanocomposites were investigated in contact angles and thermogravimetric analysis (TGA), respectively. From the experimental results, the surface modification of clay by dodecylammonium chloride led to the increases in both distance between silicate layers of about 8 A and surface acid values, as well as in the electron acceptor component (gamma(+)(s)) of surface free energy, resulting in improved interfacial adhesion between basic (or electron donor) epoxy resins and acidic (electron acceptor) clay interlayers. Also, the thermal stability of nanocomposites was highly superior to pure epoxy resin due to the presence of the well-dispersed clay nanolayer, which has a barrier property in a composite system.

  20. Toxicological evaluation of clay minerals and derived nanocomposites: a review.

    Science.gov (United States)

    Maisanaba, Sara; Pichardo, Silvia; Puerto, María; Gutiérrez-Praena, Daniel; Cameán, Ana M; Jos, Angeles

    2015-04-01

    Clays and clay minerals are widely used in many facets of our society. This review addresses the main clays of each phyllosilicate groups, namely, kaolinite, montmorillonite (Mt) and sepiolite, placing special emphasis on Mt and kaolinite, which are the clays that are more frequently used in food packaging, one of the applications that are currently exhibiting higher development. The improvements in the composite materials obtained from clays and polymeric matrices are remarkable and well known, but the potential toxicological effects of unmodified or modified clay minerals and derived nanocomposites are currently being investigated with increased interest. In this sense, this work focused on a review of the published reports related to the analysis of the toxicological profile of commercial and novel modified clays and derived nanocomposites. An exhaustive review of the main in vitro and in vivo toxicological studies, antimicrobial activity assessments, and the human and environmental impacts of clays and derived nanocomposites was performed. From the analysis of the scientific literature different conclusions can be derived. Thus, in vitro studies suggest that clays in general induce cytotoxicity (with dependence on the clay, concentration, experimental system, etc.) with different underlying mechanisms such as necrosis/apoptosis, oxidative stress or genotoxicity. However, most of in vivo experiments performed in rodents showed no clear evidences of systemic toxicity even at doses of 5000mg/kg. Regarding to humans, pulmonary exposure is the most frequent, and although clays are usually mixed with other minerals, they have been reported to induce pneumoconiosis per se. Oral exposure is also common both intentionally and unintentionally. Although they do not show a high toxicity through this pathway, toxic effects could be induced due to the increased or reduced exposure to mineral elements. Finally, there are few studies about the effects of clay minerals on

  1. Corrosion behaviour of carbon steel in the Tournemire clay

    International Nuclear Information System (INIS)

    Foct, F.; Dridi, W.; Cabrera, J.; Savoye, S.

    2004-01-01

    Carbon steels are possible materials for the fabrication of nuclear waste containers for long term geological disposal in argillaceous environments. Experimental studies of the corrosion behaviour of such materials has been conducted in various conditions. Concerning the numerous laboratory experiments, these conditions (water and clay mixture or compacted clay) mainly concern the bentonite clay that would be used for the engineered barrier. On the opposite, only few in-situ experiments has been conducted directly in the local clay of the repository site (such as Boom clay, etc.). In order to better estimate the corrosion behaviour of carbon steels in natural clay site conditions, an experimental study has been conducted jointly by EDF and IRSN in the argillaceous French site of Tournemire. In this study, A42 carbon steel specimens have been exposed in 3 different zones of the Tournemire clay formation. The first type of environmental conditions concerns a zone where the clay has not been affected by the excavation (EDZ) of the main tunnel neither by the main fracture zone of the clay formation. The second and third ones are located in the EDZ of the tunnel. In the second zone, an additional aerated water flows from the tunnel, whereas it does not in the third place. Some carbon steel specimens have been extracted after several years of exposure to these conditions. The average corrosion rate has been measured by the weight loss technique and the pitting corrosion depth has been evaluated under an optical microscope. Corrosion products have also been characterised by scanning electron microscopy and X-ray diffraction technique. Results are then discussed regarding the surrounding environmental conditions. Calculations of the oxygen transport from the tunnel through the clay and of the clay re-saturation can explain, in a first approach, the corrosion behaviour of the carbon steel in the different tested zones. (authors)

  2. Impact-Induced Clay Mineral Formation and Distribution on Mars

    Science.gov (United States)

    Rivera-Valentin, E. G.; Craig, P. I.

    2015-01-01

    Clay minerals have been identified in the central peaks and ejecta blankets of impact craters on Mars. Several studies have suggested these clay minerals formed as a result of impact induced hydrothermalism either during Mars' Noachian era or more recently by the melting of subsurface ice. Examples of post-impact clay formation is found in several locations on Earth such as the Mjolnir and Woodleigh Impact Structures. Additionally, a recent study has suggested the clay minerals observed on Ceres are the result of impact-induced hydrothermal processes. Such processes may have occurred on Mars, possibly during the Noachian. Distinguishing between clay minerals formed preor post-impact can be accomplished by studying their IR spectra. In fact, showed that the IR spectra of clay minerals is greatly affected at longer wavelengths (i.e. mid-IR, 5-25 micron) by impact-induced shock deformation while the near-IR spectra (1.0-2.5 micron) remains relatively unchanged. This explains the discrepancy between NIR and MIR observations of clay minerals in martian impact craters noted. Thus, it allows us to determine whether a clay mineral formed from impact-induced hydrothermalism or were pre-existing and were altered by the impact. Here we study the role of impacts on the formation and distribution of clay minerals on Mars via a fully 3-D Monte Carlo cratering model, including impact- melt production using results from modern hydrocode simulations. We identify regions that are conducive to clay formation and the location of clay minerals post-bombardment.

  3. Effects of biochar on hydraulic conductivity of compacted kaolin clay.

    Science.gov (United States)

    Wong, James Tsz Fung; Chen, Zhongkui; Wong, Annie Yan Yan; Ng, Charles Wang Wai; Wong, Ming Hung

    2018-03-01

    Compacted clay is widely used as capillary barriers in landfill final cover system. Recently, biochar amended clay (BAC) has been proposed as a sustainable alternative cover material. However, the effects of biochar on saturated hydraulic conductivity (k sat ) of clay with high degree of compaction is not yet understood. The present study aims to investigate the effects of biochar on k sat of compacted kaolin clay. Soil specimens were prepared by amending kaolin clay with biochar derived from peanut-shell at 0, 5 and 20% (w/w). The k sat of soil specimens was measured using a flexible water permeameter. The effects of biochar on the microstructure of the compacted clay was also investigated using MIP. Adding 5% and 20% of biochar increased the k sat of compacted kaolin clay from 1.2 × 10 -9 to 2.1 × 10 -9 and 1.3 × 10 -8 ms -1 , respectively. The increase in k sat of clay was due to the shift in pore size distribution of compacted biochar-amended clay (BAC). MIP results revealed that adding 20% of biochar shifted the dominant pore diameter of clay from 0.01-0.1 μm (meso- and macropores) to 0.1-4 μm (macropores). Results reported in this communication revealed that biochar application increased the k sat of compacted clay, and the increment was positively correlated to the biochar percentage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Clays in natural and engineered barriers for radioactive waste confinement

    International Nuclear Information System (INIS)

    2007-01-01

    The meeting covers all topics concerning natural argillaceous geological barriers and the clay material based engineered barrier systems, investigated by means of: laboratory experiments on clay samples (new analytical developments), in situ experiments in underground research laboratories, mock-up demonstrations, natural analogues, as well as numerical modelling and global integration approaches (including up-scaling processes and treatment of uncertainties). The works presented deal with: examples of broad research programs (national or international) on the role of natural and artificial clay barriers for radionuclide confinement; clay-based repository concepts: repository designs, including technological and safety issues related to the use of clay for nuclear waste confinement; geology and clay characterisation: mineralogy, sedimentology, paleo-environment, diagenesis, dating techniques, discontinuities in rock clay, fracturing, self sealing processes, role of organic matter and microbiological processes; geochemistry: pore water geochemistry, clay thermodynamics, chemical retention, geochemical modelling, advanced isotopic geochemistry; mass transfer: water status and hydraulic properties in low permeability media, pore space geometry, water, solute and gas transfer processes, colloid mediated transport, large scale movements, long-term diffusion; alteration processes: oxidation effects, hydration-dehydration processes, response to thermal stress, iron-clay interactions, alkaline perturbation; geomechanics: thermo-hydro-mechanical behaviour of clay, rheological models, EDZ characterisation and evolution, coupled behaviour and models (HM, THM, THMC). A particular interest is given to potential contributions coming from fields of activities other than radioactive waste management, which take advantage of the confinement properties of the clay barrier (oil and gas industries, gas geological storage, CO 2 geological sequestration, chemical waste isolation

  5. Clays in natural and engineered barriers for radioactive waste confinement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The meeting covers all topics concerning natural argillaceous geological barriers and the clay material based engineered barrier systems, investigated by means of: laboratory experiments on clay samples (new analytical developments), in situ experiments in underground research laboratories, mock-up demonstrations, natural analogues, as well as numerical modelling and global integration approaches (including up-scaling processes and treatment of uncertainties). The works presented deal with: examples of broad research programs (national or international) on the role of natural and artificial clay barriers for radionuclide confinement; clay-based repository concepts: repository designs, including technological and safety issues related to the use of clay for nuclear waste confinement; geology and clay characterisation: mineralogy, sedimentology, paleo-environment, diagenesis, dating techniques, discontinuities in rock clay, fracturing, self sealing processes, role of organic matter and microbiological processes; geochemistry: pore water geochemistry, clay thermodynamics, chemical retention, geochemical modelling, advanced isotopic geochemistry; mass transfer: water status and hydraulic properties in low permeability media, pore space geometry, water, solute and gas transfer processes, colloid mediated transport, large scale movements, long-term diffusion; alteration processes: oxidation effects, hydration-dehydration processes, response to thermal stress, iron-clay interactions, alkaline perturbation; geomechanics: thermo-hydro-mechanical behaviour of clay, rheological models, EDZ characterisation and evolution, coupled behaviour and models (HM, THM, THMC). A particular interest is given to potential contributions coming from fields of activities other than radioactive waste management, which take advantage of the confinement properties of the clay barrier (oil and gas industries, gas geological storage, CO{sub 2} geological sequestration, chemical waste isolation

  6. [Mechanism of tritium persistence in porous media like clay minerals].

    Science.gov (United States)

    Wu, Dong-Jie; Wang, Jin-Sheng; Teng, Yan-Guo; Zhang, Ke-Ni

    2011-03-01

    To investigate the mechanisms of tritium persistence in clay minerals, three types of clay soils (montmorillonite, kaolinite and illite) and tritiated water were used in this study to conduct the tritium sorption tests and the other related tests. Firstly, the ingredients, metal elements and heat properties of clay minerals were studied with some instrumental analysis methods, such as ICP and TG. Secondly, with a specially designed fractionation and condensation experiment, the adsorbed water, the interlayer water and the structural water in the clay minerals separated from the tritium sorption tests were fractionated for investigating the tritium distributions in the different types of adsorptive waters. Thirdly, the location and configuration of tritium adsorbed into the structure of clay minerals were studied with infrared spectrometry (IR) tests. And finally, the forces and mechanisms for driving tritium into the clay minerals were analyzed on the basis of the isotope effect of tritium and the above tests. Following conclusions have been reached: (1) The main reason for tritium persistence in clay minerals is the entrance of tritium into the adsorbed water, the interlayer water and the structural water in clay minerals. The percentage of tritium distributed in these three types of adsorptive water are in the range of 13.65% - 38.71%, 0.32% - 5.96%, 1.28% - 4.37% of the total tritium used in the corresponding test, respectively. The percentages are different for different types of clay minerals. (2) Tritium adsorbed onto clay minerals are existed in the forms of the tritiated hydroxyl radical (OT) and the tritiated water molecule (HTO). Tritium mainly exists in tritiated water molecule for adsorbed water and interlayer water, and in tritiated hydroxyl radical for structural water. (3) The forces and effects driving tritium into the clay minerals may include molecular dispersion, electric charge sorption, isotope exchange and tritium isotope effect.

  7. 1.7. Acid decomposition of kaolin clays of Ziddi Deposit. 1.7.1. The hydrochloric acid decomposition of kaolin clays and siallites

    International Nuclear Information System (INIS)

    Mirsaidov, U.M.; Mirzoev, D.Kh.; Boboev, Kh.E.

    2016-01-01

    Present article of book is devoted to hydrochloric acid decomposition of kaolin clays and siallites. The chemical composition of kaolin clays and siallites was determined. The influence of temperature, process duration, acid concentration on hydrochloric acid decomposition of kaolin clays and siallites was studied. The optimal conditions of hydrochloric acid decomposition of kaolin clays and siallites were determined.

  8. Water Retention Curves of Opalinus Clay

    Energy Technology Data Exchange (ETDEWEB)

    Villar, M. V.; Romero, F. J.

    2012-11-01

    The water retention curve of Opalinus clay samples was determined under different conditions: total and matric suction, stress or no-stress conditions, wetting and drying paths. Through the fitting of these results to the van Genuchten expression the P parameter, related to the air entry value (AEV), was obtained. The AEV is the suction value above which air is able to enter the pores of the sample, and consequently, above which 2-phase flow can take place in the soil pore structure. The samples used in this research came from two different boreholes, BHT-1 and BHG-D1, but the behaviour of them did not depend on their location, what was probably due to the fact that both were drilled in the shay facies of the Opalinus clay. There was not a distinct difference between the results obtained under total or matric suctions. In the drying paths, both the water contents and the degrees of saturation tended to be higher when total suction was applied, however the reverse trend was observed for the water contents reached in wetting paths. As well, no clear difference was observed in the water retention curves obtained in odometers under matric and total suctions, what points to the osmotic component of suction in Opalinus clay not being significant. Overall, the water contents were lower and the degrees of saturation higher when suction was applied under vertical stress, what would indicate that the water retention capacity was lower under 8 MPa vertical stress than under free volume conditions. This vertical stress value is slightly higher than the maximum in situ stress. Also, the samples showed hysteresis according to the expected behaviour, i.e. the water contents for a given suction were higher during a drying path than during a wetting path. The P values obtained were between 6 and 34 MPa, and tended to be higher for the samples tested under stress, in drying paths and when total suction was used. The air entry value calculated from the mercury intrusion porosimetry

  9. Water Retention Curves of Opalinus Clay

    International Nuclear Information System (INIS)

    Villar, M. V.; Romero, F. J.

    2012-01-01

    The water retention curve of Opalinus clay samples was determined under different conditions: total and matric suction, stress or no-stress conditions, wetting and drying paths. Through the fitting of these results to the van Genuchten expression the P parameter, related to the air entry value (AEV), was obtained. The AEV is the suction value above which air is able to enter the pores of the sample, and consequently, above which 2-phase flow can take place in the soil pore structure. The samples used in this research came from two different boreholes, BHT-1 and BHG-D1, but the behaviour of them did not depend on their location, what was probably due to the fact that both were drilled in the shay facies of the Opalinus clay. There was not a distinct difference between the results obtained under total or matric suctions. In the drying paths, both the water contents and the degrees of saturation tended to be higher when total suction was applied, however the reverse trend was observed for the water contents reached in wetting paths. As well, no clear difference was observed in the water retention curves obtained in odometers under matric and total suctions, what points to the osmotic component of suction in Opalinus clay not being significant. Overall, the water contents were lower and the degrees of saturation higher when suction was applied under vertical stress, what would indicate that the water retention capacity was lower under 8 MPa vertical stress than under free volume conditions. This vertical stress value is slightly higher than the maximum in situ stress. Also, the samples showed hysteresis according to the expected behaviour, i.e. the water contents for a given suction were higher during a drying path than during a wetting path. The P values obtained were between 6 and 34 MPa, and tended to be higher for the samples tested under stress, in drying paths and when total suction was used. The air entry value calculated from the mercury intrusion porosimetry

  10. Stabilization of Clay Soil Using Tyre Ash

    Directory of Open Access Journals (Sweden)

    Mahmood Dheyab Ahmed

    2017-06-01

    Full Text Available The planning, designing, construction of excavations and foundations in soft to very soft clay soils are always difficult. They are problematic soil that caused trouble for the structures built on them because of the low shear strength, high water content, and high compressibility. This work investigates the geotechnical behavior of soft clay by using tyre ash material burnt in air. The investigation contains the following tests: physical tests, chemical tests, consolidation test, Compaction tests, shear test, California Bearing Ratio test CBR, and model tests. These tests were done on soil samples prepared from soft clay soil; tyre ash was used in four percentages (2, 4, 6, and 8%. The results of the tests were; The soil samples which gave the value of plasticity test were 2% (25, 4% (25.18, 6% (25.3, and 8% (26.7.The soil samples which gave the value of specific gravity were 2% (2.65, 4% (2.61, 6% (2.5, and 8% (2.36.The value of maximum dry density in a compaction test observed with 2% percentage gave the value 15.8 kN/m3, the 4% gave the value 15.4 kN/m 3 34 , 6% gave 15.3 kN/m 3 and 8%with 15.2 kN/m3 .Samples that gave the values of undrained shear strength test were 2% (55 kN/m 2 , 4% (76 kN/m2 , 6% (109 kN/m 2, and 8% (122 kN/m 2. The best of them is 8%. The sample that gave the best value for swelling test was 8%.The best value for compression index Cc was in 8%.The results of CBR test, were improved in all soil samples. The soil samples which gave the value for CBR were 2% (3.507%, 4% (4.308%, 6% (5.586%, and 8% (9.569%. The best value was obtained from 8%.

  11. Do scaly clays control seismicity on faulted shale rocks?

    Science.gov (United States)

    Orellana, Luis Felipe; Scuderi, Marco M.; Collettini, Cristiano; Violay, Marie

    2018-04-01

    One of the major challenges regarding the disposal of radioactive waste in geological formations is to ensure isolation of radioactive contamination from the environment and the population. Shales are suitable candidates as geological barriers. However, the presence of tectonic faults within clay formations put the long-term safety of geological repositories into question. In this study, we carry out frictional experiments on intact samples of Opalinus Clay, i.e. the host rock for nuclear waste storage in Switzerland. We report experimental evidence suggesting that scaly clays form at low normal stress (≤20 MPa), at sub-seismic velocities (≤300 μm/s) and is related to pre-existing bedding planes with an ongoing process where frictional sliding is the controlling deformation mechanism. We have found that scaly clays show a velocity-weakening and -strengthening behaviour, low frictional strength, and poor re-strengthening over time, conditions required to allow the potential nucleation and propagation of earthquakes within the scaly clays portion of the formation. The strong similarities between the microstructures of natural and experimental scaly clays suggest important implications for the slip behaviour of shallow faults in shales. If natural and anthropogenic perturbations modify the stress conditions of the fault zone, earthquakes might have the potential to nucleate within zones of scaly clays controlling the seismicity of the clay-rich tectonic system, thus, potentially compromising the long-term safeness of geological repositories situated in shales.

  12. Large Strain Analysis of Electro-Osmosis Consolidation for Clays

    NARCIS (Netherlands)

    Yuan, J.

    2015-01-01

    Consolidation of soft clay creates a lot of problems in foundation engineering, because of the very low clay permeability and high compressibility. Primary consolidation takes a long time to complete if the material is left consolidating under atmospheric evaporation, and traditional dewatering

  13. Centrifuge modelling of rigid piles in soft clay

    DEFF Research Database (Denmark)

    Klinkvort, R.T.; Poder, M.; Truong, P.

    2016-01-01

    of this study is to employ centrifuge modelling in order to derive experimental p-y curves for rigid piles embedded in over-consolidated soft clay. A kaolin clay sample was prepared and pre-consolidated by applying a constant pressure at the soil surface, while different over-consolidation ratios were achieved...

  14. Learning of Cross-Sectional Anatomy Using Clay Models

    Science.gov (United States)

    Oh, Chang-Seok; Kim, Ji-Young; Choe, Yeon Hyeon

    2009-01-01

    We incorporated clay modeling into gross anatomy and neuro-anatomy courses to help students understand cross-sectional anatomy. By making clay models, cutting them and comparing cut surfaces to CT and MR images, students learned how cross-sectional two-dimensional images were created from three-dimensional structure of human organs. Most students…

  15. Nanoporous polymer--clay hybrid membranes for gas separation.

    Science.gov (United States)

    Defontaine, Guillaume; Barichard, Anne; Letaief, Sadok; Feng, Chaoyang; Matsuura, Takeshi; Detellier, Christian

    2010-03-15

    Nanohybrid organo-inorgano clay mineral-polydimethylsiloxane (PDMS) membranes were prepared by the reaction of pure and/or modified natural clay minerals (Sepiolite and montmorillonite) with PDMS in hexane, followed by evaporation of the solvent at 70 degrees C. The membranes were characterized by means of XRD, SEM, ATD-TG and solid state (29)Si magic angle spinning (MAS) and cross-polarization (CP) CP/MAS NMR. The morphology of the membranes depends on the content loading of clay mineral. For low content, the membrane composition is homogeneous, with well dispersed nanoparticles of clay into the polymer matrix, whereas for higher clay content, the membranes are constituted also of a mixture of well dispersed nanoparticles into the polymer, but in the presence of agglomerations of small clay particles. Quantitative (29)Si MAS NMR demonstrated a strong correlation between the clay content of the membrane and the average length of the PDMS chain, indicating that the nanohybrid material is made of clay particles covalently linked to the PDMS structure. This is particularly the case for Sepiolite with has a high density of Q(2) silanol sites. The separation performances of the prepared membranes were tested for CO(2)/CH(4) and O(2)/N(2) mixtures. The observed separation factors showed an increase of the selectivity in the case of CO(2)/CH(4) in comparison with membranes made from PDMS alone under the same conditions. 2009 Elsevier Inc. All rights reserved.

  16. Comparative evaluation of clays from Abakaliki Formation with ...

    African Journals Online (AJOL)

    The characteristics of clays from Abakaliki Formation, Southeastern Nigeria was evaluated to establish its suitability as drilling mud when compared with commercial bentonite such as Wyoming bentonite. The chemical, mineralogical and geotechnical properties were employed in assessing the suitability of Abakaliki clay as ...

  17. Toxic element composition of multani mitti clay for nutritional safety

    International Nuclear Information System (INIS)

    Waheed, S.; Faiz, Y.; Rahman, S.; Siddique, N.

    2013-01-01

    Geophagy of multani mitti (MM) clay is very common in central Pakistan especially amongst women. It was therefore mandatory to establish baseline levels of toxic elements in this clay for its safe dietary consumption by consumers of different genders, age groups and physical states. Instrumental neutron activation analysis and atomic absorption spectrometry techniques were used to determine the nutritional safety of MM clay for oral intake. All quantified toxic elements were detected at trace levels with composition in the descending order; Pb > Br > As > Sb > Hg > Cd. Comparison of these elements in MM clay with other clays shows that As, Cd, and Pb, are lowest in MM clay while its Br and Hg contents are high. Highest weekly dietary intakes of As, Br, Cd, Hg, and Sb were found to be 18, 0.05, 1.6, 9.2 and 1.1 % of the respective recommended provisional tolerable weekly intakes. The findings of this study show that As, Br, Cd, Hg and Sb in MM clay are well below the tolerance levels. However its Pb concentration is very high and may pose health concerns. The data presented in this study can be used as national base level guideline for geophagy of MM clay by men, women (normal, pregnant and lactating) and children. (author)

  18. Elastic deformation behaviour of Palaeogene clay from Fehmarn Belt area

    DEFF Research Database (Denmark)

    Awadalkarim, Ahmed; Foged, Niels Nielsen; Fabricius, Ida Lykke

    2014-01-01

    Palaeogene clay samples were obtained by high quality boring and sampling techniques (Geobore S-system), during the extensive site investigations for building a bridge in the Fehmarn Belt area to link between Rødbyhavn in Denmark and Puttgarden in Germany. The Palaeogene clay is rich in smectite...

  19. Calcination of kaolinite clay particles for cement production

    DEFF Research Database (Denmark)

    Gebremariam, Abraham Teklay; Yin, Chungen; Rosendahl, Lasse

    2014-01-01

    Kaolinite rich clay particles calcined under certain conditions can attain favorable pozzolanic properties and can be used to substitute part of the CO2 intensive clinker in cement production. To better guide calcination of a clay material, a transient one-dimensional single particle model...

  20. Assessment of heavy metals leachability from traditional clay pots ...

    African Journals Online (AJOL)

    As heavy metals are toxic in trace concentrations, due to bioaccumulation, traditional clay pots constitute a public health hazard when used as food contact material. However, as the geochemical properties of clay are different from regions to region and the techniques of making them differ, further studies should be ...

  1. Recovery of Porosity and Permeability for High Plasticity Clays

    DEFF Research Database (Denmark)

    Krogsbøll, Anette; Foged, Niels Nielsen

    to be the case for high plasticity clays that are uncemented, and with a high content of clay minerals, especially smectite. Oedometer tests on samples from the Paleogene period show that 80% or more of the compaction will recover when unloaded, and if unloaded to a stress lower than in situ stress level...

  2. Clay mineral distribution on the Kerala continental shelf and slope

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Nair, R.R.; Hashimi, N.H.

    Seventy-five sediment samples collected from the Kerala continental shelf and slope during the 17th and 71st Cruises of @iRV gaveshani@@ were analysed by X-ray diffraction for clay mineral cntent. The distribution of total clay (< 4~k fraction...

  3. Mineralogical composition and functionality of clays used for pottery ...

    African Journals Online (AJOL)

    Mineralogical composition and functionality of clays used for pottery education by physically challenged learners at the Ikwezi-Lokusa Educational Centre, Eastern Cape, South Africa. ... The clays were mineralogically characterised using Munsell Soil Color Chart, X-ray powder diffractometry (XRPD) and optical microscopy.

  4. Preparation of intercalated polyaniline/clay nanocomposite and its

    Indian Academy of Sciences (India)

    Intercalated composite of polyaniline and clay has been reported. The composite was prepared by in situ polymerization of aniline within the layers of `illite' clay. The composite was characterized for its structural, spectral, and microscopic properties. At higher level of loading the layered structure of composite breaks ...

  5. Indigenous Knowledge Applied to the Use of Clays for Cosmetic ...

    African Journals Online (AJOL)

    The use of clay for cosmetic purposes in Africa is an age-old long-standing practice, which has been practiced through all regions of the continent. Red, white, yellow and their related shades of clays, in combination with other natural substances such as plant and animal extracts have over time been used by different ...

  6. Quality evaluation of processed clay soil samples | Steiner-Asiedu ...

    African Journals Online (AJOL)

    Introduction: This study assessed the microbial quality of clay samples sold on two of the major Ghanaian markets. Methods: The study was a cross-sectional assessing the evaluation of processed clay and effects it has on the nutrition of the consumers in the political capital town of Ghana. The items for the examination was ...

  7. The acid solubility test of clay mineral under microwave

    International Nuclear Information System (INIS)

    Zheng Ying; Niu Yuqing; Wu Peisheng; Niu Xuejun

    2001-01-01

    The acid solubility test of Al 3+ in clay from some uranium ores under microwave is introduced. The result shows that the concentration of Al 3+ in solution and the acid consumption increase rapidly under microwave comparing with normal leaching condition. It is infeasible to adopt microwave slacking method for intensively leaching uranium from uranium ore containing more clay

  8. "Clay grounds” in Denmark: from soil to canvas

    DEFF Research Database (Denmark)

    Buti, David; Vila, Anna; Haack Christensen, Anne

    decorative scheme showed that at least two grounds from those paintings consist mainly of clay mixed with iron and magnesium-containing compounds. Furthermore, both SEM-EDX and µRaman measurements clearly highlighted the presence of a large amount of quartz particles. It is well known that clay is a sheet...

  9. A Classification of Clay-Rich Subaqueous Density Flow Structures

    NARCIS (Netherlands)

    Hermidas, N.; Eggenhuisen, Joris T.; Jacinto, Ricardo Silva; Luthi, S.M.; Toth, Ferenc; Pohl, Florian

    2018-01-01

    This study presents a classification for subaqueous clay-laden sediment gravity flows. A series of laboratory flume experiments were performed using 9%, 15%, and 21% sediment mixture concentrations composed of sand, silt, clay, and tap water, on varying bed slopes of 6°, 8°, and 9.5°, and with

  10. Hydroxyapatite clay for gap filling and adequate bone ingrowth.

    Science.gov (United States)

    Maruyama, M; Terayama, K; Ito, M; Takei, T; Kitagawa, E

    1995-03-01

    In uncemented total hip arthroplasty, a complete filling of the gap between femoral prosthesis and the host bone is difficult and defects would remain, because the anatomy of the reamed intramedullary canal cannot fit the prosthesis. Therefore, it seems practical to fill the gap with a clay containing hydroxyapatite (HA), which has an osteoconductive character. The clay (HA clay) is made by mixing HA granules (size 0.1 mm or more) having a homogeneous pore distribution and a porosity of 35-48 vol%, and a viscous substance such as a saline solution of sodium alginate (SSSA). In the first experiment, the ratio of HA granules and sodium alginate in SSSA is set for the same handling properties of HA clay and polymethylmethacrylate bone cement (standard viscosity) before hardening. As a result, the ratio is set for 55 wt% of HA in the clay and 12.5 wt% of sodium alginate in SSSA (i.e., HA:sodium alginate:saline solution = 9.8:1:7). In the second study, the gap between the femoral stem and bone model is completely filled with HA clay. However, the gap is not filled only with HA granules or HA granules mixed with saline solution. In the third animal experiment, using an unloaded model, histology shows that HA clay has an osteoconductive property bridging the gap between the implant and the cortical bone without any adverse reaction. HA clay is considered a useful biomaterial to fill the gap with adequate bone ingrowth.

  11. Morphology and melt rheology of nylon 11/clay nanocomposites

    NARCIS (Netherlands)

    He, Xiaofeng; Yang, Jun; Zhu, Lianchao; Wang, Biao; Sun, Guangping; Lv, Pengfei; Phang, In Yee; Liu, Tianxi

    2006-01-01

    Nylon 11 (PA11)/clay nanocomposites have been prepared by melt-blending, followed by melt-extrusion through a capillary. Transmission electron microscopy shows that the exfoliated clay morphology is dominant for low nanofiller content, while the intercalated one is prevailing for high filler

  12. STUDY OF THERMAL AND ACID STABILITY OF BENTONITE CLAY

    Directory of Open Access Journals (Sweden)

    Karna Wijaya

    2010-06-01

    Full Text Available The thermal and acid stability of the bentonite clays (Na- and Ca-bentonite have been tested. The thermal stability testing has been carried out by heating 5 gram of the clays  for five hours at 200, 300 and 500 °C respectively, meanwhile acid stability testing was performed by immersing 5 gram clays into 100 mL sulphuric acid 1M, 2M and 3M for 24 hours. The tested clays, then were characterized by means of X-Ray difractometry and IR-spectroscopy methods. The characterization results showed that upon heating, both Ca- and Na-bentonites indicated same thermal stability. However, upon acid treatment, Na-bentonite was found relatively stabiler and more resistance then Ca-bentonite.   Keywords: bentonite, clay, thermal stability, acid stability.

  13. Nanocomposites of PP and bentonite clay modified with different surfactants

    International Nuclear Information System (INIS)

    Rodrigues, Andre W.B.; Agrawal, Pankaj; Araujo, Edcleide M.; Melo, Tomas J.A.; Ueki, Marcelo M.

    2009-01-01

    The aim of this work was the development of nano composites of polypropylene (PP) and national bentonite clay modified with different surfactants. The results of X-Ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) showed that the organophilization process was effective. The surfactants led to a significant increase in the basal spacing of Brasgel PA clay. XRD results of the mixture PP/Brasgel PA clay modified with Praepagem WB surfactant indicated that a nanocomposite with intercalated structure was formed. When the Brasgel PA clay was modified with Praepagem HY surfactant, DRX results indicated that a micro composite was formed. Screw speed, clay content and PP viscosity had no influence on the XRD pattern of the obtained materials. (author)

  14. Performance of Kaolin Clay on the Concrete Pavement

    Science.gov (United States)

    Abdullah, M. E.; Jaya, R. P.; Shahafuddin, M. N. A.; Yaacob, H.; Ibrahim, M. H. Wan; Nazri, F. M.; Ramli, N. I.; Mohammed, A. A.

    2018-05-01

    This paper investigates the performance of concrete pavement containing kaolin clay with their engineering properties and to determine the optimum kaolin clay content. The concrete used throughout the study was designed as grade 30 MPa strength with constant water to cement ratio of 0.49. The compressive strength, flexural strength and water absorption test was conducted in this research. The concrete mix designed with kaolin clay as cement replacement comprises at 0%, 5%, 10% and 15% by the total weight of cement. The results indicate that the strength of pavement concrete decreases as the percentage of kaolin clay increases. It also shows that the water absorption increases with the percentage of cement replacement. However, 5% kaolin clay is found to be the optimum level to replace cement in a pavement concrete.

  15. Decantation time of evaluation on bentonite clays fractionation

    International Nuclear Information System (INIS)

    Gomes, J.; Menezes, R.R.; Neves, G.A.; Lira, H.L; Santana, L.N.L.

    2009-01-01

    Bentonite clays present a great number of industrial uses, from petroleum to pharmaceutics and cosmetic industry. The bentonite clay present particles with very fine particles that is responsible by the vast application of these materials. However, commercial clays present wide particle size distribution and a significant content of impurities, particularly quartz, in the form of silt and fine silt. So, the aim of this work is to analyze the effect of the stirring and decantation time in the deagglomeration, purification and size separation of the bentonite clay particles from Paraiba. The clays were characterized by X-ray diffraction and particle size distribution. Based on the results it was observed the decantation time give the elimination of the agglomerates formed by submicrometric particles. The uses of decantation column give separation of the fraction below 200nm. (author)

  16. Brazilian clay organophilization aiming its use in oil / water removal

    International Nuclear Information System (INIS)

    Mota, M.F.; Lima, W.S.; Oliveira, G.C.; Silva, M.M.; Rodrigues, M.G.F.

    2012-01-01

    Clays when subjected to modification with the addition of organic surfactant are called organoclays acquire hydrophobic character, they have an affinity for organic compounds. The organoclays can be used as adsorbents are considered promising agents in environmental control. The objective is to prepare organoclays clays from commercial use in order to remove organic contaminants. The clay used was gray, as polycationic, supplied by Süd-Chemie company and the quaternary ammonium salt was cetyltrimethylammonium bromide (Cetremide). The fresh samples and organoclay were characterized by the technique of X-ray diffraction (XRD), Cation Exchange Capacity, testing expansion and affinity with organic compounds: Swelling of Foster and adsorption capacity. The results showed appropriate conditions organophilic process. Through XRD confirmed the increase in basal spacing for the modified clay in relation to the clay in nature. (author)

  17. Clays in natural and engineered barriers for radioactive waste confinement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    Andra organised an International Symposium on the use of Natural and Engineered Clay-based Barriers for the Containment of Radioactive Waste hold at the Congress Centre of Tours, France, in March 2005. The symposium provided an opportunity to take stock of the potential properties of the clay-based materials present in engineered or natural barriers in order to meet the containment specifications of a deep geological repository for radioactive waste. It was intended for specialists working in the various disciplines involved with clays and clay based minerals, as well as scientists from agencies and organisations dealing with investigations on the disposal of high-level and long-lived radioactive waste. The themes of the Symposium included geology, geochemistry, transfers of materials, alteration processes, geomechanics, as well as the recent developments regarding the characterisation of clays, as well as experiments in surface and underground laboratories. The symposium consisted of plenary sessions, parallel specialized sessions and poster sessions. (author)

  18. Long-term performance of geosynthetic clay liners in cappings

    International Nuclear Information System (INIS)

    Maubeuge, K.P. von; Fricke, A.

    1998-01-01

    Geosynthetic clay liners (GCLs) are relatively thin composite materials combining bentonite clay and geosynthesis (usually geotextiles). GCLs have been employed by the waste industry for well over a decade now, and their level of usage is rapidly increasing world-wide. In landfill facilities, GCLs are generally used to replace or augment compacted clay liners. Until recently, the decision to do so has primarily been based on the availability of clay material on site (i.e., economic considerations). However, the advantages in using a GCL over other sealing elements such as compacted clay are not only economic but technically based, and the economic benefits extend beyond the construction phase, as a thin GCL can increase the revenue earning potential of a facility. This paper will highlight the shear behaviour of GCLs and demonstrate the long-term stability. (orig.)

  19. Effect of Compaction on Compressive Strength of Unfired Clay Blocks

    International Nuclear Information System (INIS)

    Lakho, N.A.; Zardari, M.A.; Pathan, A.A.

    2016-01-01

    This study investigates the possible use of unfired compacted clay blocks as a substitute of CSEB (Compressed Stabilized Earth Blocks) for the construction of economical houses. Cubes of 150 mm size were cut from the clay blocks which were compacted at various intensities of pressure during the casting. The results show that the compressive strength of the clay cubes increased with the compacting pressure to which the blocks were subjected during casting. The average crushing strength of the cubes, sawed from clay blocks that were subjected to compacting pressure of 7.2 MPa, was found to be 4.4 MPa. This value of compressive strength is about 50 percent more than that of normal CSEB. This study shows that the compacted clay blocks could be used as economical walling material as replacement of CSEB. (author)

  20. Structural characterization of clays commercially used in red ceramics

    International Nuclear Information System (INIS)

    Brito, E.M.; Moura, J.K.L.; Souza, R.B.; Brandim, A.S.

    2014-01-01

    The use of clays hills being an alternative to clay floodplain, due to environmental protection laws. The research project aims at the morphological and chemical characterization of hills clays used industrially for the production of ceramic tiles and blocks. Therefore, two types of methods were known commercially in the region of Teresina-PI through diffraction of X-rays (X-DR), scanning electron microscopy (SEM) and energy dispersive spectrometry X-ray (EDS). It can be observed that the samples have a high percentage of quartz, hematite still having in its constitution aluminum oxide, zirconium oxide and titanium oxide. The results show that the clays are clays and montmorillonites may be used for the production of ceramic tiles and blocks, but as the proportion of using the same will be focusing the next job. (author)

  1. Characterization and analysis of epoxy/clay nanotubes composites

    International Nuclear Information System (INIS)

    Sene, Tarcisio S.; Kock, Thyago; Coelho, Luiz A.F.; Becker, Daniela

    2011-01-01

    An DGEBA epoxy matrix was used aiming to achieve a nanocomposite material, through the dispersion of (CNT) via mechanical stirring followed by sonication. In this work the following characterization were performed: mechanical characterization, differential scanning calorimetry (DSC), wide angle X-ray diffraction (WXRD) and scanning electron microscopy (SEM). The addition of CNT and modified clays promoted the increase of modulus of the epoxy matrix, and a synergistic effect between CNT and both clays could be presumed. SEM images of the fracture surface show the difference between the fracture surface area and the presence of clusters among the samples, allowing a correlation with the modulus of elasticity. X-ray diffractograms from 2Θ = 5 deg showed no peaks for modified clay samples, however it is possible to affirm that modified clay platelets are forming a less organized structure compared to the structure of the clay as natural in epoxy. (author)

  2. Cytocompatibility and uptake of halloysite clay nanotubes.

    Science.gov (United States)

    Vergaro, Viviana; Abdullayev, Elshad; Lvov, Yuri M; Zeitoun, Andre; Cingolani, Roberto; Rinaldi, Ross; Leporatti, Stefano

    2010-03-08

    Halloysite is aluminosilicate clay with hollow tubular structure of 50 nm external diameter and 15 nm diameter lumen. Halloysite biocompatibility study is important for its potential applications in polymer composites, bone implants, controlled drug delivery, and for protective coating (e.g., anticorrosion or antimolding). Halloysite nanotubes were added to different cell cultures for toxicity tests. Its fluorescence functionalization by aminopropyltriethosilane (APTES) and with fluorescently labeled polyelectrolyte layers allowed following halloysite uptake by the cells with confocal laser scanning microscopy (CLSM). Quantitative Trypan blue and MTT measurements performed with two neoplastic cell lines model systems as a function of the nanotubes concentration and incubation time indicate that halloysite exhibits a high level of biocompatibility and very low cytotoxicity, rendering it a good candidate for household materials and medicine. A combination of transmission electron microscopy (TEM), scanning electron microscopy (SEM), and scanning force microscopy (SFM) imaging techniques have been employed to elucidate the structure of halloysite nanotubes.

  3. Composites Based on Fly Ash and Clay

    International Nuclear Information System (INIS)

    Fidancevska, E.; Jovanov, V.; Angusheva, B.; Srebrenkoska, V.

    2014-01-01

    Fly ash is a waste generated from the coal combustion during the production of electricity in the thermal power plants. It presents industrial by-product containing Technologically Enhanced Natural Occurring Radioactive Materials (TENORM) with the great potential for valorisation. Fly ash is successfully utilized in cement and concrete industry, also in ceramics industry as component for manufacturing bricks and tiles, and recently there are many investigations for production of glass-ceramics from fly ash. Although the utilization of fly ash in construction and civil engineering is dominant, the development of new alternative application for its further exploitation into new products is needed. This work presents the possibility for fly ash utilization for fabricating dense composites based on clay and fly ash with the potential to be used in construction industry

  4. Sorption Energy Maps of Clay Mineral Surfaces

    International Nuclear Information System (INIS)

    Cygan, Randall T.; Kirkpatrick, R. James

    1999-01-01

    A molecular-level understanding of mineral-water interactions is critical for the evaluation and prediction of the sorption properties of clay minerals that may be used in various chemical and radioactive waste disposal methods. Molecular models of metal sorption incorporate empirical energy force fields, based on molecular orbital calculations and spectroscopic data, that account for Coulombic, van der Waals attractive, and short-range repulsive energies. The summation of the non-bonded energy terms at equally-spaced grid points surrounding a mineral substrate provides a three dimensional potential energy grid. The energy map can be used to determine the optimal sorption sites of metal ions on the exposed surfaces of the mineral. By using this approach, we have evaluated the crystallographic and compositional control of metal sorption on the surfaces of kaolinite and illite. Estimates of the relative sorption energy and most stable sorption sites are derived based on a rigid ion approximation

  5. Sorption of radionuclides on London clay

    International Nuclear Information System (INIS)

    Berry, J.A.; Bourke, P.J.; Green, A.; Littleboy, A.K.

    1989-02-01

    Techniques for studying the sorption of radionuclides on London clay have been investigated. This work involved the use of through-diffusion, in-diffusion, high-pressure convection and batch methods to study the sorption of iodide, strontium, caesium and americium. Through-diffusion and high-pressure convection methods were found to be most useful for investigating weakly and moderately sorbing nuclides and give realistic values for sorptivity. The batch technique remains the most practical method of obtaining large quantities of data within a relatively short timescale but gives very high sorptivity values. It is however very useful for intercomparisons of nuclides or geological media. The in-diffusion method requires further refinement for use with strongly sorbing nuclides. Good agreement between through-diffusion and high-pressure convection methods was obtained for the sorptivity of strontium, whilst trends observed for caesium by through-diffusion were confirmed by batch measurements. (author)

  6. Mullins' effect in polymer/clay nanocomposites

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville; Klitkou, Rasmus

    2012-01-01

    of memory of deformation history: when two samples are subjected to loading programs that differ along the first n ¡ 1 cycles and coincide afterwards, their stress– strain diagrams coincide starting from the nth cycle. Constitutive equations are developed in cyclic viscoelasticity and viscoplasticity...... of nanocomposites, and adjustable parameters in the stress–strain relations are found by fitting the experimental data. Ability of the model to predict the fading memory phenomenon is confirmed by numerical simulation.......Abstract. Experimental data are reported on polypropylene/clay nanocomposites in uniaxial cyclic tensile tests at room temperature (oscillations between maximum strains and the zero minimum stress with maximum strains increasing monotonically with number of cycles). Observations reveal fading...

  7. STABILISATION OF SILTY CLAY SOIL USING CHLORIDE

    Directory of Open Access Journals (Sweden)

    TAMADHER T. ABOOD

    2007-04-01

    Full Text Available The object of this paper is to investigate the effect of adding different chloride compounds including (NaCl, MgCl2, CaCl2 on the engineering properties of silty clay soil. Various amounts of salts (2%, 4%, and 8% were added to the soil to study the effect of salts on the compaction characteristics, consistency limits and compressive strength. The main findings of this study were that the increase in the percentage of each of the chloride compounds increased the maximum dry density and decrease the optimum moisture content. The liquid limit, plastic limit and plasticity index decreased with the increase in salt content. The unconfinedcompressive strength increased as the salt content increased.

  8. Tricky Treats

    Centers for Disease Control (CDC) Podcasts

    2008-08-04

    The Eagle Books are a series of four books that are brought to life by wise animal characters - Mr. Eagle, Miss Rabbit, and Coyote - who engage Rain That Dances and his young friends in the joy of physical activity, eating healthy foods, and learning from their elders about health and diabetes prevention. Tricky Treats shows children the difference between healthy snacks and sweet treats.  Created: 8/4/2008 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 8/5/2008.

  9. Diazonium cation-exchanged clay: an efficient, unfrequented route for making clay/polymer nanocomposites.

    Science.gov (United States)

    Salmi, Zakaria; Benzarti, Karim; Chehimi, Mohamed M

    2013-11-05

    We describe a simple, off-the-beaten-path strategy for making clay/polymer nanocomposites through tandem diazonium salt interface chemistry and radical photopolymerization. Prior to photopolymerization, sodium montmorillonite (MMT) was ion exchanged with N,N'-dimethylbenzenediazonium cation (DMA) from the tetrafluoroborate salt precursor. DMA acts as a hydrogen donor for benzophenone in solution; this pair of co-initiators permits us to photopolymerize glycidyl methacrylate (GMA) between the lamellae of the diazonium-modified clay, therefore providing intercalated MMT-PGMA nanocomposites with an onset of exfoliation. This work conclusively provides a new approach for bridging reactive and functional polymers to layered nanomaterials via aryl diazonium salts in a simple, fast, efficient cation-exchange approach.

  10. Antifungal activity of streptomycetes isolated bentonite clay

    Directory of Open Access Journals (Sweden)

    V. P. Shirobokov

    2016-12-01

    Full Text Available Aim. To investigate the biological activity of streptomycetes, isolated from Ukrainian bentonite clay. Methods. For identification of the investigated microorganisms there were used generally accepted methods for study of morpho-cultural and biochemical properties and sequencing of 16Ѕ rRNA producer. Antagonistic activity of the strain was determined by agar diffusion and agar block method using gram-positive, gram-negative microorganisms and fungi. Results. Research of autochthonous flora from bentonite clay of Ukrainian various deposits proved the existence of stable politaxonomic prokaryotic-eukaryotic consortia there. It was particularly interesting that the isolated microorganisms had demonstrated clearly expressed antagonistic properties against fungi. During bacteriological investigation this bacterial culture was identified like representative of the genus Streptomyces. Bentonite streptomycetes, named as Streptomyces SVP-71, inagar mediums (agar block method inhibited the growth of fungi (yeast and mold; zones of growth retardation constituted of 11-36 mm, and did not affect the growth of bacteria. There were investigated the inhibitory effects of supernatant culture fluid, ethanol and butanol extracts of biomass streptomycetes on museum and clinical strains of fungi that are pathogenic for humans (Candida albicans, C. krusei, C. utilis, C. parapsilosis, C. tropicalis, C. kefir, S. glabrata, C. lusitaniae, Aspergillus niger, Mucor pusillus, Fusarium sporotrichioides. It has been shown that research antifungal factor had 100% of inhibitory effect against all fungi used in experiments in vitro. In parallel, it was found that alcohol extracts hadn’t influence to the growth of gram-positive and gram-negative bacteria absolutely. It was shown that the cultural fluid supernatant and alcoholic extracts of biomass had the same antagonistic effect, but with different manifestation. This evidenced about identity of antifungal substances

  11. Sorption of Metal Ions on Clay Minerals.

    Science.gov (United States)

    Schlegel; Manceau; Chateigner; Charlet

    1999-07-01

    The local structural environment of Co sorbed on hectorite (a magnesian smectite) has been investigated by polarized EXAFS (P-EXAFS) spectroscopy on a self-supporting film of Co-sorbed hectorite. This sorption sample was prepared by contacting Co and hectorite at pH 6.5 and at high ionic strength (0.3 M NaNO3) to favor pH-dependent sorption reaction over cation exchange. A self-supporting film was elaborated after 120 h of reacting time, when apparent quasi-equilibrium conditions were attained. The half-width at half maximum of the orientation distribution of c* axis of individual clay platelets off the film normal was determined by quantitative texture analysis, and found to be equal to 18.9 degrees. Co K-edge P-EXAFS spectra were recorded at angles between the incident beam and the film normal equal to 0 degrees, 35 degrees, 50 degrees, and 60 degrees; the 90 degrees spectrum was obtained by extrapolation. Spectral analysis led to the identification of the two nearest cationic subshells containing 1.6 +/- 0.4 Mg at 3.03 Å and 2.2 +/- 0.5 Si at 3.27 Å. These distances are respectively characteristic of edge-sharing linkages between Mg and Co octahedra and of corner-sharing linkages between Co octahedra and Si tetrahedra, as in clay structures. The angular dependence of the Co-Mg and Co-Si contributions indicates that Co-Mg pairs are oriented parallel to the film plane, whereas Co-Si pairs are not. These results are interpreted by the formation of Co inner-sphere mononuclear surface complexes located at the edges of hectorite platelets, in the continuity of the (Mg, Li) octahedral sheet. Copyright 1999 Academic Press.

  12. Dimensioning of lining galleries in deep clays

    International Nuclear Information System (INIS)

    Bernaud, D.; Rousset, G.

    1991-01-01

    The aim of the work presented in this report is to study the mechanical behaviour of lining galleries in deep clays. This text constitutes a part of the researches on the feasibility of a geological disposal of radioactive waste, which the scope is to assure the gallery long term stabilization and also to optimize its dimensioning. In particular, we are interested here in the study of a closure controlled lining, that constitutes a direct application of the convergence-confinement method, especially well fitted to deep clays. The presentation and interpretation of the convergence controlled lining test, which was performed in the experimental gallery of Mol in Belgium, is given in this report. The instrumentation was conceived in order to find out the stress field exerced by the rockmass on the lining, the internal stress field inside the lining and the gallery closure. The analysis of all measurements results, obtained between november 1987 and December 1989, shows that they are all in good agreement and that the lining design was well chosen. Two years after the gallery construction, the average closure is of the order of 2% and the average confinement pressure is about 1.6 MPa (the third of the lithostatic pressure). The time dependent effects of the rockmass are very well modelled by the non linear elasto-viscoplastic law developed at L.M.S. with the laboratory tests. The elastic-plastic model of the lining are shown to be well fitted to simulate the sliding of the ribs. Finally, the numerical results have shown a very good agreement with the measurements results

  13. Hydrophobic Modification of Layered Clays and Compatibility for Epoxy Nanocomposites

    Directory of Open Access Journals (Sweden)

    Jiang-Jen Lin

    2010-04-01

    Full Text Available Recent studies on the intercalation and exfoliation of layered clays with polymeric intercalating agents involving poly(oxypropylene-amines and the particular uses for epoxy nanocomposites are reviewed. For intercalation, counter-ionic exchange reactions of clays including cationic layered silicates and anionic Al-Mg layered double hydroxide (LDH with polymeric organic ions afforded organoclays led to spatial interlayer expansion from 12 to 92 Å (X-ray diffraction as well as hydrophobic property. The inorganic clays of layered structure could be modified by the poly(oxypropyleneamine-salts as the intercalating agents with molecular weights ranging from 230 to 5,000 g/mol. Furthermore, natural montmorillonite (MMT clay could be exfoliated into thin layer silicate platelets (ca. 1 nm thickness in one step by using polymeric types of exfoliating agents. Different lateral dimensions of MMT, synthetic fluorinated Mica and LDH clays had been cured into epoxy nanocomposites. The hydrophobic amine-salt modification resulting in high spacing of layered or exfoliation of individual clay platelets is the most important factor for gaining significant improvements of properties. In particular, these modified clays were reported to gain significant improvements such as reduced coefficient of thermal expansion (CTE, enhanced thermal stability, and hardness. The utilization of these layered clays for initiating the epoxy self-polymerization was also reported to have a unique compatibility between clay and organic resin matrix. However, the matrix domain lacks of covalently bonded crosslink and leads to the isolation of powder material. It is generally concluded that the hydrophobic expansion of the clay inter-gallery spacing is the crucial step for enhancing the compatibility and the ultimate preparation of the advanced epoxy materials.

  14. Aluminium - Cobalt-Pillared Clay for Dye Filtration Membrane

    Science.gov (United States)

    Darmawan, A.; Widiarsih

    2018-04-01

    The manufacture of membrane support from cobalt aluminium pillared clay has been conducted. This research was conducted by mixing a clay suspension with pillared solution prepared from the mixture of Co(NO3)2.6H2O and AlCl3.6H2O. The molar ratio between Al and Co was 75:25 and the ratio of [OH-]/[metal] was 2. The clay suspension was stirred for 24 hours at room temperature, filtered and dried. The dried clay was then calcined at 200°C, 300°C and 400°C with a ramp rate of 2°C/min. Aluminium-cobalt-pillared clay was then characterized by XRD and GSA and moulded become a membrane support for subsequent tests on dye filtration. The XRD analysis showed that basal spacing (d 001) value of aluminium cobalt was 19.49 Å, which was higher than the natural clay of 15.08Å however, the basal spacing decreased with increasing calcination temperature. The result of the GSA analysis showed that the pore diameter of the aluminium cobalt pillared clay membrane was almost the same as that of natural clay that were 34.5Å and 34.2Å, respectively. Nevertheless, the pillared clay has a more uniform pore size distribution. The results of methylene blue filtration measurements demonstrated that the membrane filter support could well which shown by a clear filtrate at all concentrations tested. The value of rejection and flux decreased with the increasing concentration of methylene blue. The values of dye rejection and water flux reached 99.89% and 5. 80 x 10-6 kg min-1, respectively but they decreased with increasing concentration of methylene blue. The results of this study indicates that the aluminium-pillared clay cobalt could be used as membrane materials especially for ultrafiltration.

  15. Heteroaggregation of titanium dioxide nanoparticles with natural clay colloids.

    Science.gov (United States)

    Labille, Jérôme; Harns, Carrie; Bottero, Jean-Yves; Brant, Jonathan

    2015-06-02

    To better understand and predict the fate of engineered nanoparticles in the water column, we assessed the heteroaggregation of TiO2 nanoparticles with a smectite clay as analogues for natural colloids. Heteroaggregation was evaluated as a function of water salinity (10(-3) and 10(-1) M NaCl), pH (5 and 8), and selected nanoparticle concentration (0-4 mg/L). Time-resolved laser diffraction was used, coupled to an aggregation model, to identify the key mechanisms and variables that drive the heteroaggregation of the nanoparticles with colloids. Our data show that, at a relevant concentration, nanoparticle behavior is mainly driven by heteroaggregation with colloids, while homoaggregation remains negligible. The affinity of TiO2 nanoparticles for clay is driven by electrostatic interactions. Opposite surface charges and/or high ionic strength favored the formation of primary heteroaggregates via the attachment of nanoparticles to the clay. The initial shape and dispersion state of the clay as well as the nanoparticle/clay concentration ratio also affected the nature of the heteroaggregation mechanism. With dispersed clay platelets (10(-3) M NaCl), secondary heteroaggregation driven by bridging nanoparticles occurred at a nanoparticle/clay number ratio of greater than 0.5. In 10(-1) M NaCl, the clay was preaggregated into larger and more spherical units. This favored secondary heteroaggregation at lower nanoparticle concentration that correlated to the nanoparticle/clay surface area ratio. In this latter case, a nanoparticle to clay sticking efficiency could be determined.

  16. Hydrophobic Modification of Layered Clays and Compatibility for Epoxy Nanocomposites

    Science.gov (United States)

    Lin, Jiang-Jen; Chan, Ying-Nan; Lan, Yi-Fen

    2010-01-01

    Recent studies on the intercalation and exfoliation of layered clays with polymeric intercalating agents involving poly(oxypropylene)-amines and the particular uses for epoxy nanocomposites are reviewed. For intercalation, counter-ionic exchange reactions of clays including cationic layered silicates and anionic Al-Mg layered double hydroxide (LDH) with polymeric organic ions afforded organoclays led to spatial interlayer expansion from 12 to 92 Å (X-ray diffraction) as well as hydrophobic property. The inorganic clays of layered structure could be modified by the poly(oxypropylene)amine-salts as the intercalating agents with molecular weights ranging from 230 to 5,000 g/mol. Furthermore, natural montmorillonite (MMT) clay could be exfoliated into thin layer silicate platelets (ca. 1 nm thickness) in one step by using polymeric types of exfoliating agents. Different lateral dimensions of MMT, synthetic fluorinated Mica and LDH clays had been cured into epoxy nanocomposites. The hydrophobic amine-salt modification resulting in high spacing of layered or exfoliation of individual clay platelets is the most important factor for gaining significant improvements of properties. In particular, these modified clays were reported to gain significant improvements such as reduced coefficient of thermal expansion (CTE), enhanced thermal stability, and hardness. The utilization of these layered clays for initiating the epoxy self-polymerization was also reported to have a unique compatibility between clay and organic resin matrix. However, the matrix domain lacks of covalently bonded crosslink and leads to the isolation of powder material. It is generally concluded that the hydrophobic expansion of the clay inter-gallery spacing is the crucial step for enhancing the compatibility and the ultimate preparation of the advanced epoxy materials.

  17. Verification of substitution of bentonites by montmorillonitic clays summary report on Czech montmorillonitic clays

    International Nuclear Information System (INIS)

    Carlson, L.; Keto, P.

    2006-10-01

    Czech bentonites and smectite-rich clays were characterised in order to study if they could be used as buffer and backfill materials instead of non-Czech commercial bentonites. The characterisation work was orgnized by RAWRA (the Czech Radioactive Waste Repository Authority) and the main part of the work was performed in the Czech Republic at Charles University and at Czech Technical University. Parallel and complementary characterisation was conducted in Finland in Sweden. This report was compiled with the aim to summarise the results, and to compare the methods and results gained in different testing laboratories. The characterisation included mineralogical, chemical and geotechnical investigations and experiments on thermal stability and sorption. There were some variations between the results gained in different laboratories. This was mainly due to differences between the testing methods used but also due to heterogeneity of the samples. The Czech bentonite-clays from Rokle and Strance clay deposits contained relatively high amount of swelling minerals and thus can be considered as potential buffer and backfill materials. (orig.)

  18. Thermo Gravimetric and Differential Thermal Analysis of Clay of Western Rajasthan (india)

    Science.gov (United States)

    Shekhawat, M. S.

    The paper presents the study of thermo gravimetric and differential thermal analysis of blended clay. Western part of Rajasthan (India) is rich resource of Ball clays and it is mainly used by porcelain, sanitary ware, and tile industry. The quality and grade of clay available in the region vary from one deposit to other. To upgrade the fired colour and strength properties, different variety of clays may be blended together. The paper compares the results of thermal analysis one of blended clay B2 with reference clay of Ukraine which is imported by industries owners. The result revealed that the blended clay is having mineral kaolinite while the Ukrainian clay is Halloysite.

  19. Gassmann Modeling of Acoustic Properties of Sand-clay Mixtures

    Science.gov (United States)

    Gurevich, B.; Carcione, J. M.

    The feasibility of modeling elastic properties of a fluid-saturated sand-clay mixture rock is analyzed by assuming that the rock is composed of macroscopic regions of sand and clay. The elastic properties of such a composite rock are computed using two alternative schemes.The first scheme, which we call the composite Gassmann (CG) scheme, uses Gassmann equations to compute elastic moduli of the saturated sand and clay from their respective dry moduli. The effective elastic moduli of the fluid-saturated composite rock are then computed by applying one of the mixing laws commonly used to estimate elastic properties of composite materials.In the second scheme which we call the Berryman-Milton scheme, the elastic moduli of the dry composite rock matrix are computed from the moduli of dry sand and clay matrices using the same composite mixing law used in the first scheme. Next, the saturated composite rock moduli are computed using the equations of Brown and Korringa, which, together with the expressions for the coefficients derived by Berryman and Milton, provide an extension of Gassmann equations to rocks with a heterogeneous solid matrix.For both schemes, the moduli of the dry homogeneous sand and clay matrices are assumed to obey the Krief's velocity-porosity relationship. As a mixing law we use the self-consistent coherent potential approximation proposed by Berryman.The calculated dependence of compressional and shear velocities on porosity and clay content for a given set of parameters using the two schemes depends on the distribution of total porosity between the sand and clay regions. If the distribution of total porosity between sand and clay is relatively uniform, the predictions of the two schemes in the porosity range up to 0.3 are very similar to each other. For higher porosities and medium-to-large clay content the elastic moduli predicted by CG scheme are significantly higher than those predicted by the BM scheme.This difference is explained by the fact

  20. Final report on physical test program of Spanish clays (Saponites and bentonites)

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, R.; Karnland, O.; Sanden, T.

    1996-10-01

    Two Spanish candidate buffer clays were hydrothermally treated and then investigated with respect to the physical properties and chemical and mineralogical compositions. four temperatures were used: room temperature 70 degree centigree, 120 degree centigree and 170 degree centigree, and three periods of testing: 10 days, 60 days and 360 days. The hydrothermal treatment was made by use of pressurized vessels with different solutions rich in Na``+/Ca``2+, K``+ and Mg``2+, respectively. The testing comprised determination of physical properties, e.g. the hydraulic conductivity and the rheological behavior, as well as of chemical and mineralogical changes. The hydraulic conductivity was found to be significantly affected by the type of dominant cation. With time, the conductivity dropped due to microstructural homogenization but exposure to higher temperatures caused an increased conductivity. The mechanical strength was highest of the Saponites primarily due to colloid-chemical effects. The dominant chemical effect up to 120 degree centigree was cation exchange. At 170 degree centigree significant dissolution took place, releasing silica from the clay. Mineral changes were insignificant and no conversion of the smectite to illite could be identified in the montmorillonitic clay, while some slight alteration of saponite to illite took place to about the same extent at all temperatures, including room temperature.

  1. Quantifying the clay content with borehole depth and impact on reservoir flow

    Science.gov (United States)

    Sarath Kumar, Aaraellu D.; Chattopadhyay, Pallavi B.

    2017-04-01

    This study focuses on the application of reservoir well log data and 3D transient numerical model for proper optimization of flow dynamics and hydrocarbon potential. Fluid flow through porous media depends on clay content that controls porosity, permeability and pore pressure. The pressure dependence of permeability is more pronounced in tight formations. Therefore, preliminary clay concentration analysis and geo-mechanical characterizations have been done by using wells logs. The assumption of a constant permeability for a reservoir is inappropriate and therefore the study deals with impact of permeability variation for pressure-sensitive formation. The study started with obtaining field data from available well logs. Then, the mathematical models are developed to understand the efficient extraction of oil in terms of reservoir architecture, porosity and permeability. The fluid flow simulations have been done using COMSOL Multiphysics Software by choosing time dependent subsurface flow module that is governed by Darcy's law. This study suggests that the reservoir should not be treated as a single homogeneous structure with unique porosity and permeability. The reservoir parameters change with varying clay content and it should be considered for effective planning and extraction of oil. There is an optimum drawdown for maximum production with varying permeability in a reservoir.

  2. Effect of by-product steel slag on the engineering properties of clay soils

    Directory of Open Access Journals (Sweden)

    Faisal I. Shalabi

    2017-10-01

    Full Text Available Clay soils, mainly if they contain swelling minerals such as smectite or illite, may cause severe damage to structures, especially when these soils are subjected to wetting and drying conditions. High expansion and reduction in shear strength and foundation bearing capacity will take place due to the increase in water content of these soils. The engineering properties of these kinds of soils can be improved by using additives and chemical stabilizers. In this work, by-product steel slag was used to improve the engineering properties of clay soils. Lab and field experimental programs were developed to investigate the effect of adding different percentages of steel slag on plasticity, swelling, compressibility, shear strength, compaction, and California bearing ratio (CBR of the treated materials. The results of tests on the clay soil showed that as steel slag content increased, the soil dry density, plasticity, swelling potential, and cohesion intercept decreased and the angle of internal friction increased. For the CBR, the results of the tests showed an increase in the CBR value with the increase in slag content.

  3. Preparation and properties of biodegradable starch–clay nanocomposites

    KAUST Repository

    Chung, Yi-Lin

    2010-01-01

    Well-dispersed starch-clay nanocomposites were prepared by adding a dilute clay dispersion to a solution of starch followed by coprecipitation in ethanol. The clay didn\\'t significantly influence the type of crystalline structure of starch molecules although the amount of crystallinity appears to be somewhat lower in the nanocomposites. The nanocomposites show improved modulus and strength without a decrease in elongation at break. The increase in modulus and strength is 65% and 30%, respectively for the nanocomposite containing 5 wt.% clay compared to the unfilled starch materials. Further increases in clay result in deterioration in properties most likely due to poorer clay dispersion and lower polymer crystallinity. As the amount of water increases, the modulus of both pure starch and starch nanocomposites decreases, although the change is less pronounced in the nanocomposites suggesting that the addition of clay to form nanocomposites can improve the stability of starch-based products during transportation and storage. © 2009 Elsevier Ltd. All rights reserved.

  4. Clay-Enriched Silk Biomaterials for Bone Formation

    Science.gov (United States)

    Mieszawska, Aneta J.; Llamas, Jabier Gallego; Vaiana, Christopher A.; Kadakia, Madhavi P.; Naik, Rajesh R.; Kaplan, David L.

    2011-01-01

    The formation of silk protein/clay composite biomaterials for bone tissue formation is described. Silk fibroin serves as an organic scaffolding material offering mechanical stability suitable for bone specific uses. Clay montmorillonite (Cloisite ® Na+) and sodium silicate are sources of osteoinductive silica-rich inorganic species, analogous to bioactive bioglass-like bone repair biomaterial systems. Different clay particle-silk composite biomaterial films were compared to silk films doped with sodium silicate as controls for support of human bone marrow derived mesenchymal stem cells (hMSCs) in osteogenic culture. The cells adhered and proliferated on the silk/clay composites over two weeks. Quantitative real-time RT-PCR analysis revealed increased transcript levels for alkaline phosphatase (ALP), bone sialoprotein (BSP), and collagen type 1 (Col I) osteogenic markers in the cells cultured on the silk/clay films in comparison to the controls. Early evidence for bone formation based on collagen deposition at the cell-biomaterial interface was also found, with more collagen observed for the silk films with higher contents of clay particles. The data suggest that the silk/clay composite systems may be useful for further study toward bone regenerative needs. PMID:21549864

  5. Environmental Degradation and Durability of Epoxy-Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Raman P. Singh

    2010-01-01

    Full Text Available This experimental investigation reports on the durability of epoxy-clay nanocomposites upon exposure to multiple environments. Nanocomposites are fabricated by mixing the clay particles using various combinations of mechanical mixing, high-shear dispersion, and ultrasonication. Clay morphology is characterized using X-ray diffraction and transmission electron microscopy. Specimens of both neat epoxy and the epoxy-clay nanocomposite are subjected to two environmental conditions: combined UV radiation and condensation on 3-hour repeat cycle and constant temperature-humidity, for a total exposure duration of 4770 hours. The presence of nanoscale clay inhibits moisture uptake, as demonstrated by exposure to constant temperature-humidity. Nonetheless, both materials lose mass under exposure to combined UV radiation and condensation due to the erosion of epoxy by a synergistic process. Surprisingly, the epoxy-clay specimens exhibit greater mass loss, as compared to neat epoxy. Mechanical testing shows that either environment does not significant affect the flexure modulus of either material. On the other hand, both materials undergo degradation in flexural strength when exposed to either environment. However, the epoxy-clay nanocomposite retains 37% more flexure strength than the neat epoxy after 4072 hours of exposure.

  6. Polyethersulfone/clay membranes and its water permeability

    International Nuclear Information System (INIS)

    Cavalho, Thamyres Cardoso de; Medeiros, Vanessa da Nobrega; Araujo, Edcleide Maria de; Lira, Helio Lucena; Leite, Amanda Melissa Damiao

    2017-01-01

    Membranes can be considered polymeric or inorganic films that function as a semipermeable barrier to filtration on a molecular scale, separating two phases and restricting, totally or partially, the transportation of one or more chemical species (solute) present in the solution. Therefore, the aim of this work is to produce polyethersulfone membranes (PES) and polyethersulfone/clay by phase inversion technique and evaluate the presence of clay in obtaining membranes for wastewater treatment. The used solvent was dimethylformamide (DMF) and clays were Brasgel PA (MMT) and Cloisite Na (CL Na) in the proportion of 3 to 5% (wt.). By Xray diffraction (XRD), the membranes with 3% of MMT and CL Na clays apparently had partially exfoliated structures. For the composition with 5% of CL Na a small peak was observed, which indicates that this is possibly an intercalated structure or microcomposite. By scanning electron microscopy (SEM), visualizes that the pure surface of the pure PES membrane a structure apparently without pores was observed in the used magnification and without roughness surface when compared to membranes with clay. The measurements of contact angle indicated that the inclusion of clay altered the wetting ability of the membranes. The flow with distilled water for all membranes started high and over time reached a stabilization level. Thus, it can be concluded that the presence and the content of clay altered the morphology of the membrane, contributing to an increase in water flow. (author)

  7. Preparation and properties of biodegradable starch–clay nanocomposites

    KAUST Repository

    Chung, Yi-Lin; Ansari, Seema; Estevez, Luis; Hayrapetyan, Suren; Giannelis, Emmanuel P.; Lai, Hsi-Mei

    2010-01-01

    Well-dispersed starch-clay nanocomposites were prepared by adding a dilute clay dispersion to a solution of starch followed by coprecipitation in ethanol. The clay didn't significantly influence the type of crystalline structure of starch molecules although the amount of crystallinity appears to be somewhat lower in the nanocomposites. The nanocomposites show improved modulus and strength without a decrease in elongation at break. The increase in modulus and strength is 65% and 30%, respectively for the nanocomposite containing 5 wt.% clay compared to the unfilled starch materials. Further increases in clay result in deterioration in properties most likely due to poorer clay dispersion and lower polymer crystallinity. As the amount of water increases, the modulus of both pure starch and starch nanocomposites decreases, although the change is less pronounced in the nanocomposites suggesting that the addition of clay to form nanocomposites can improve the stability of starch-based products during transportation and storage. © 2009 Elsevier Ltd. All rights reserved.

  8. Performance of polymeric films based thermoplastic starch and organophilic clay

    International Nuclear Information System (INIS)

    Cipriano, P.B.; Costa, A.N.M.; Araujo, S.S.; Araujo, A.R.A.; Canedo, E.L.; Carvalho, L.H.

    2010-01-01

    The aim of this work was the development and investigation of the properties of flat films of LDPE/corn thermoplastic starch (TPS). A bentonite clay (Argel) was organophilized and characterized by XRD. This clay (1%) in both pristine and organophilic forms was added to the matrix (LDPE) and to LDPE/TPS systems with TPS contents varying from 5-20% w/w. The films manufactured (LDPE, LDPE/Clay, LDPE/TPS, LDPE/TPS/Clay) were characterized. Results indicate that water vapor permeability is dependent and increases with TPS content which was attributed to the higher affinity of water by TPS. TPS and Clay addition to LDPE led to significant changes in film properties with respect to the neat LDPE. In general,tensile and perforation forces increased with clay and TPS contents; the strength of thermo sealed films lowered with natural clay addition and increased with TPS and organoclay incorporation and, in general, dynamic friction coefficient decrease with organoclay and TPS addition. Best overall properties were obtained for the systems containing the organoclay and optimal properties were achieved for the 5%TPS10 LDPE1% ANO system. (author)

  9. Stochastic Dynamics of Clay Translocation and Formation of Argillic Horizons

    Science.gov (United States)

    Calabrese, S.; Richter, D. D., Jr.; Porporato, A. M.

    2017-12-01

    The formation of argillic horizons in vertical soil profiles is mainly attributed to lessivage, namely the transport of clay from an upper E horizon to a deeper illuviated horizon. Because of the long timescales involved in this phenomenon, quantitative modeling is useful to explore the role of clay lessivage on soil formation and sub-surface clay accumulation. The limitations of detailed models of colloidal transport to short timescales make it necessary to resort to simple models. Here, we present a parsimonious model of clay transport in which lessivage is interpreted stochastically. Clay particles approach the soil surface at a speed equal to the erosion rate and are intermittently transported to deeper soil layers when percolation events occur or removed by erosion. Along with the evolution of clay particles trajectories, the model predicts the vertical clay profile, the depth of the B horizon, and the mean time to erosion. Dimensional analysis reveals the two dimensionless parameters governing the dynamics, leading to a new classification of soil types based on erosion rates and intensity of lessivage.

  10. Environmental Degradation and Durability of Epoxy-Clay Nanocomposites

    International Nuclear Information System (INIS)

    Singh, R.P.; Zunjarrao, S.C.; Pandey, G.; Khait, M.; Korach, C.S.

    2010-01-01

    This experimental investigation reports on the durability of epoxy-clay nanocomposites upon exposure to multiple environments. Nanocomposites are fabricated by mixing the clay particles using various combinations of mechanical mixing, high-shear dispersion, and ultrasonication. Clay morphology is characterized using X-ray diffraction and transmission electron microscopy. Specimens of both neat epoxy and the epoxy-clay nanocomposite are subjected to two environmental conditions: combined UV radiation and condensation on 3-hour repeat cycle and constant temperature-humidity, for a total exposure duration of 4770 hours. The presence of nanoscale clay inhibits moisture uptake, as demonstrated by exposure to constant temperature-humidity. Nonetheless, both materials lose mass under exposure to combined UV radiation and condensation due to the erosion of epoxy by a synergistic process. Surprisingly, the epoxy-clay specimens exhibit greater mass loss, as compared to neat epoxy. Mechanical testing shows that either environment does not significant affect the flexure modulus of either material. On the other hand, both materials undergo degradation in flexural strength when exposed to either environment. However, the epoxy-clay nanocomposite retains 37% more flexure strength than the neat epoxy after 4072 hours of exposure.

  11. Thermal treatment of toxic metals of industrial hazardous wastes with fly ash and clay

    Energy Technology Data Exchange (ETDEWEB)

    Singh, I.B. [Regional Research Laboratory, Council of Scientific and Industrial Research, Hoshangabad Road, Bhopal 462026 (India)]. E-mail: ibsingh58@yahoo.com; Chaturvedi, K. [Regional Research Laboratory, Council of Scientific and Industrial Research, Hoshangabad Road, Bhopal 462026 (India); Morchhale, R.K. [Regional Research Laboratory, Council of Scientific and Industrial Research, Hoshangabad Road, Bhopal 462026 (India); Yegneswaran, A.H. [Regional Research Laboratory, Council of Scientific and Industrial Research, Hoshangabad Road, Bhopal 462026 (India)

    2007-03-06

    Waste generated from galvanizing and metal finishing processes is considered to be a hazardous due to the presence of toxic metals like Pb, Cu, Cr, Zn, etc. Thermal treatment of such types of wastes in the presence of clay and fly ash can immobilizes their toxic metals to a maximum level. After treatment solidified mass can be utilized in construction or disposed off through land fillings without susceptibility of re-mobilization of toxic metals. In the present investigation locally available clay and fly ash of particular thermal power plant were used as additives for thermal treatment of both of the wastes in their different proportions at 850, 900 and 950 deg. C. Observed results indicated that heating temperature to be a key factor in the immobilization of toxic metals of the waste. It was noticed that the leachability of metals of the waste reduces to a negligible level after heating at 950 deg. C. Thermally treated solidified specimen of 10% waste and remaining clay have shown comparatively a higher compressive strength than clay fired bricks used in building construction. Though, thermally heated specimens made of galvanizing waste have shown much better strength than specimen made of metal finishing waste. The lechability of toxic metals like Cr, Cu, Pb and Zn became far below from their regulatory threshold after heating at 950 deg. C. Addition of fly ash did not show any improvement either in engineering property or in leachability of metals from the solidified mass. X-ray diffraction (XRD) analysis of the solidified product confirmed the presence of mixed phases of oxides of metals.

  12. Elaboration of protocol for characterization of clay as a filling material and coverage for surface repository

    International Nuclear Information System (INIS)

    Santos, Daisy Mary Marchezini dos

    2017-01-01

    The nuclear energy in its various applications generates wastes that must be properly treated. The Radioactive Waste Management covers operations since generation of the waste until to its storage in repository ensuring the protection of man and of environment of the possible negative impacts. The radioactive waste are segregated, treated, conditioned in suitable packaging and posteriorly are stored or disposal in repository. The “RBMN Project” is a priority project of CNEN to implementation the repository for the deposition of low and intermediate level radioactive waste generated by nuclear energy activities in Brazil, proposing a definitive solution for its storage. Engineered and natural barriers as the filling layer and coverage layer will compose the disposal system of a near surface repository, concept proposed by the “RBMN Project”. The use these barriers views to avoid or restrict the release of radionuclides present in waste for the humans beings and environment. The waterproofing barriers are composed of clays. Certainly, for the national repository, will be used those clays existing in the place where it will be implanted it. So some fundamentals tests will have to be carried for to verify the suitability of these clays as barriers. These tests were determined and realized with a reference clay, a brazilian bentonite constituted of 67.2% montmorillonite. The results were compared with national and international literature of materials with similar mineralogical features. The values found with 95% reliance were 9.73±0,35 μm for granulometric size. For the moisture content were 13,3±0,6% and for capacity of cationic exchange were , 816±9 mmol.kg"-"1. For the hydraulic conductivity, without the use of internal pressure, it was obtained maximum value of 59.0% saturated. In addition, during the observed period, there was no percolation in the test specimen submitted to internal pressure of 200 kPa. This result leads to the conclusion that the

  13. Influence of carbonate micro-fabrics on the failure strength of Callovo-Oxfordian clay stones and Opalinus Clay

    International Nuclear Information System (INIS)

    Klinkenberg, M.; Dohrmann, R.; Kaufhold, S.; Siegesmund, S.

    2010-01-01

    Document available in extended abstract form only. The potential use of clay stones as host rock for radioactive waste disposal is currently investigated. For this application, hydraulic conductivity, swelling properties, water uptake, rheological and mechanical properties are of great importance. The Opalinus Clay (Mont-Terri, Switzerland) and the Callovo- Oxfordian clay stone (France) are the most frequently studied clay stones. One goal is to develop a numerical model being able to predict the mechanical behaviour of clay stones under repository-like conditions. Experimental investigations reveal that Opalinus Clay and Callovo-Oxfordian clay stone behave different with respect to the dependence of mechanical strength on the carbonate content. The failure strength of Opalinus Clay decreases with increasing carbonate content, whereas it increases with increasing carbonate content when Callovo-Oxfordian clay stone is considered. To supply proper data and enable reliable model assumptions, the use of suitable experimental techniques for the description of the microstructure is indispensable. After mechanical testing, samples were taken perpendicular to the bedding and polished sections were prepared. The micro-fabrics were investigated using scanning electron microscopy (SEM) and image analysis. Backscattered electron (BSE) images were used for the image analysis because carbonates can be extracted by grey level analysis. The image analysis of the extracted particles provides the following parameters: area, longest and shortest axis of an ellipse (surrounding the particle), perimeter, the angle to horizontal (longest axis), and the aspect ratio (longest axis/shortest axis). Callovo-Oxfordian clay stone shows a homogenous distribution of fine-grained carbonates and dovetail connection of calcium carbonate with the clayey matrix. In contrast Opalinus Clay shows large elongated carbonate grains (high aspect ratios) of shell fragments. Cracks are mostly related to these

  14. Law of nonlinear flow in saturated clays and radial consolidation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    It was derived that micro-scale amount level of average pore radius of clay changed from 0.01 to 0.1 micron by an equivalent concept of flow in porous media. There is good agreement between the derived results and test ones. Results of experiments show that flow in micro-scale pore of saturated clays follows law of nonlinear flow. Theoretical analyses demonstrate that an interaction of solid-liquid interfaces varies inversely with permeability or porous radius. The interaction is an important reason why nonlinear flow in saturated clays occurs. An exact mathematical model was presented for nonlinear flow in micro-scale pore of saturated clays. Dimension and physical meanings of parameters of it are definite. A new law of nonlinear flow in saturated clays was established. It can describe characteristics of flow curve of the whole process of the nonlinear flow from low hydraulic gradient to high one. Darcy law is a special case of the new law. A mathematical model was presented for consolidation of nonlinear flow in radius direction in saturated clays with constant rate based on the new law of nonlinear flow. Equations of average mass conservation and moving boundary, and formula of excess pore pressure distribution and average degree of consolidation for nonlinear flow in saturated clay were derived by using an idea of viscous boundary layer, a method of steady state in stead of transient state and a method of integral of an equation. Laws of excess pore pressure distribution and changes of average degree of consolidation with time were obtained. Results show that velocity of moving boundary decreases because of the nonlinear flow in saturated clay. The results can provide geology engineering and geotechnical engineering of saturated clay with new scientific bases. Calculations of average degree of consolidation of the Darcy flow are a special case of that of the nonlinear flow.

  15. Effect of clay minerals on the stabilization of black cotton and lateritic soils

    International Nuclear Information System (INIS)

    Nyambok, I.O.

    1986-01-01

    The problem associated with black cotton and lateritic soils because of the swelling-shrinkage property of their constituent clay minerals were investigated. Samples of black cotton lateritic soils were collected from different parts of Kenya. The samples were analysed for their mineral compositions and later treated with hydrated lime in order to eliminate the swelling shrinkage behaviour. The samples were subsequently tested for their engineering properties in a soil mechanics laboratory using shear box and Casagrande apparatus. It was found that the chemical treatment of the soils with hydrated lime removes their plastic property and improves their shear strength. (author)

  16. Study of the behaviour of clay by frequency analysis of the seismic wave

    International Nuclear Information System (INIS)

    Sloovere, P. de.

    1990-01-01

    Any alteration in the mechanical characteristics of a medium modifies the frequency spectrum of a signal passing through the medium. In order to make use of this property, it was first necessary to construct a trial shear wave hammer generator. The waves transmitted in this way are received by a sound detector system, then they are treated by an appropriate computer program. The device has been applied successfully in the Boom clay in the vicinity of the CEN/SCK underground laboratory in Mol (Belgium)

  17. Considering clay rock heterogeneity in radionuclide retention

    International Nuclear Information System (INIS)

    Grambow, B.; Montavon, G.; Tournassat, C.; Giffaut, E.; Altmann, S.

    2010-01-01

    Document available in extended abstract form only. The Callovo-Oxfordian clay rock formation has a strong retention capacity for radionuclides, a favorable condition for the implementation of a nuclear waste repository. Principal retaining minerals are illite, and inter-stratified illite/smectite (I/S). Radionuclide retention has been studied on illite, illite/smectite and on clay rock obtained from different locations and data for retention on bentonite (80% smectite) are available. Sorption depends on the type of mineral, composition of mineralogical assemblages, individual mineral ion exchange capacities, ion distribution on exchange sites, specific surface areas, surface site types and densities for surface complexation as well as on water/rock ratios, temperature etc. As a consequence of mineralogical and textural variations, radionuclide retention properties are expected to vary with depth in the Callovo-Oxfordian formation. Using a simple additivity approach for the case of sorption of Cs and Ni it is shown that models and databases for illite and bentonite can be used to describe sorption in heterogeneous clay rock systems. A surface complexation/ion-exchange model as proposed by Bradbury and Baeyens without electrostatic contributions, was used directly as far as acid base properties are concerned but was modified with respect to sorption constants, in order to describe Na-, Ca, and Cs montmorillonite and bentonite MX-80 with a single set of surface complexation constants and also to account for carbonate and sulphate concentrations in groundwater. The model is integrated into the geochemical code PHREEQC considering dissolution/ precipitation/solubility constraints of accessory minerals (calcite, illite, celestite, quartz). Site densities for surface complexation and ion exchange are derived from the mass fractions of illite and of smectite in illite/smectite obtained from an overall fit of measured CEC data from all samples of the EST205 drill core

  18. Acid activation of natural clays aiming their application in adsorption

    International Nuclear Information System (INIS)

    Silva, M.M. da; Sousa, A.K.F. de; Lima, W.S.; Vasconcelos, P.N.M. de; Rodrigues, M. G.F.

    2012-01-01

    Clays of smectite type have wide application in industrial, mainly due to their adsorption properties. However, it is necessary to subject them to chemical treatments to optimize their potential. This study aimed to analyze the effects of acid activation on the clay Brasgel fresh. In the acid activation was used concentrated hydrochloric acid at different concentrations (3M, 4.5 M and 6 M) at a temperature of 70 ° C for 30 minutes. The samples fresh and activated technique were characterized by X-ray Diffraction (XRD). The results show that the properties of clay after activation are improved, it could be used as adsorbents in the treatment of wastewater. (author)

  19. Studies on the acid activation of Brazilian smectitic clays

    Directory of Open Access Journals (Sweden)

    Valenzuela Díaz Francisco R.

    2001-01-01

    Full Text Available Fuller's earth and acid activated smectitic clays are largely used as bleaching earth for the industrial processing of vegetable, animal and mineral oils and waxes. The paper comments about the nomenclature used for these materials, the nature of the acid activation of smectitic clays (bentonites, activation laboratory procedures and presents a review of the acid activation of bentonites from 20 deposits from several regions of Brazil. The activated clays were tested and show good decolorizing power for soybean, castor, cottonseed, corn and sunflower oils.

  20. Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Marc in het Panhuis

    2011-04-01

    Full Text Available The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that the electrical response upon exposure to humid atmosphere is influenced by clay-chitosan interactions, i.e., the resistance of clay–CNT materials decreases, whereas that of clay–CNT–chitosan increases.

  1. Characterization of clay minerals; Caracterizacion de minerales arcillosos

    Energy Technology Data Exchange (ETDEWEB)

    Diaz N, C.; Olguin, M.T.; Solache R, M.; Alarcon H, T.; Aguilar E, A. [Gerencia de Ciencias Basicas, Direccion de Investigacion Cientifica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    The natural clays are the more abundant minerals on the crust. They are used for making diverse industrial products. Due to the adsorption and ion exchange properties of these, a great interest for developing research directed toward the use of natural clays for the waste water treatment has been aroused. As part of such researches it is very important to carry out previously the characterization of the interest materials. In this work the results of the mineral and elemental chemical composition are presented as well as the morphological characteristics of clay minerals from different regions of the Mexican Republic. (Author)

  2. Fired products of Cr-smectite clays in nitrogen

    Directory of Open Access Journals (Sweden)

    C. Volzone

    2004-12-01

    Full Text Available The products of Cr-smectite clays heated to 1350 ° C in nitrogen were evaluated by X-ray diffraction and chemical analysis. Cr-smectite clays were prepared at room temperature by contact between smectite clays and Cr species contained in OH-Cr solutions. The Cr species were prepared using chromium nitrate solution by addition of NaOH solution with OH/Cr = 2. Products of firing in nitrogen at the high temperature were different (magnesia chromite, donathite, iron chromium oxide and picrochromite depending on the type of isomorphous substitution of the smectite structure and the amount of retained chromium.

  3. Fired products of Cr-smectite clays in nitrogen

    OpenAIRE

    C. Volzone; A. M. Cesio

    2004-01-01

    The products of Cr-smectite clays heated to 1350 ° C in nitrogen were evaluated by X-ray diffraction and chemical analysis. Cr-smectite clays were prepared at room temperature by contact between smectite clays and Cr species contained in OH-Cr solutions. The Cr species were prepared using chromium nitrate solution by addition of NaOH solution with OH/Cr = 2. Products of firing in nitrogen at the high temperature were different (magnesia chromite, donathite, iron chromium oxide and picrochromi...

  4. Inter-layered clay stacks in Jurassic shales

    Science.gov (United States)

    Pye, K.; Krinsley, D. H.

    1983-01-01

    Scanning electron microscopy in the backscattered electron mode is used together with energy-dispersive X-ray microanalysis to show that Lower Jurassic shales from the North Sea Basin contain large numbers of clay mineral stacks up to 150 microns in size. Polished shale sections are examined to determine the size, shape orientation, textural relationships, and internal compositional variations of the clays. Preliminary evidence that the clay stacks are authigenic, and may have formed at shallow burial depths during early diagenesis, is presented.

  5. Processing and characterization of Polystyrene/cornstarch/organophilic clay hybrids

    International Nuclear Information System (INIS)

    Oliveira, Carlos Ivan R. de; Amorim, Ywrrenan C.; Andrade, Cristina T. de

    2011-01-01

    Polystyrene/cornstarch composite blends with organophilic Cloisite 15A were prepared in an internal mixer in the presence of maleic anhydride (MA). The contents of clay were 1, 3 and 5%, based on the weight of the blend. The results obtained by X-ray diffraction revealed significant intercalation and exfoliation of clay particles within the polymeric moiety, which indicate increased interaction between the components of the nanocomposites. Thermogravimetric analysis results revealed the increase in thermal stability for the compatibilized blends in relation to the noncompatibilized PS/starch blends. The composites showed better thermal stability with increasing clay content. (author)

  6. Clay characterization of Monte Alegre-RN, Brazil

    International Nuclear Information System (INIS)

    Alencar, M.I.; Ferreira, O.F.; Ren, D.G.; Cunha, J.M.R.; Harima, E.

    2011-01-01

    This study aimed to characterize the clay from the municipality of Monte Alegre in Rio Grande do Norte. Clay (popularly known as tabatinga) is used in brick kilns for producing bricks and tiles. This study also verified the possibility of using this for industrial ceramics and ceramic tiles. The following techniques were used for characterization: chemical and mineralogical analysis which found the composition of this material the presence of quartz and kaolinite, plasticity index where the result was that the clay has plasticity null; solid residue content was 60, 19%, the determination of loss on ignition was 8.70% on checking the color of the burning got creamy clear. (author)

  7. Methods for obtention of PS/clay nanocomposites

    International Nuclear Information System (INIS)

    Lins, Pedro G.; Valera, Ticiane S.; Coelho, Caio P.D.; Demarquette, Nicole R.

    2009-01-01

    In this work, nanocomposites of Polystyrene (PS) and organoclay were obtained using a twin-screw extruder and a mixer Haake. A commercial clay named Cloisite 20A was used. The clay and the nanocomposites were characterized by X-Ray Diffraction. The rheological properties were investigated carrying out small amplitude oscillatory strain (SAOS). The results of X-ray diffraction showed that the polymer was incorporated by the organoclay. The results of SAOS indicated a better clay dispersion for the samples obtained using the mixer. (author)

  8. Initial settlements of rock fills on soft clay

    OpenAIRE

    Pedersen, Truls Martens

    2012-01-01

    Rock fills that hit the seabed will remold the underlying material. If this material is a clay with sufficiently low shear strength, it will adopt rheological properties, causing flow through the rock fill, and contributing to the initial settlements of the rock fill in addition to conventional consolidation theory. The settlements of the rocks depend upon the height of the rock fill and how the rocks have been laid out. This is due to the viscosity of the clay, and the fact that clay is thix...

  9. Influence of herbicide structure, clay acidity, and humic acid coating on acetanilide herbicide adsorption on homoionic clays.

    Science.gov (United States)

    Liu, Weiping; Gan, Jianying; Yates, Scott R

    2002-07-03

    Adsorption of chloroacetanilide herbicides on homoionic montmorillonite was studied by coupling batch equilibration and FT-IR analysis. Adsorption decreased in the order metolachlor > acetochlor > alachlor > propachlor on Ca(2+)- or Mg(2+)-saturated clays and in the order metolachlor > alachlor > acetachlor > propachlor on Al(3+)- or Fe(3+)-saturated clays. FT-IR spectra showed that the carbonyl group of the herbicide molecule was involved in bonding. For the same herbicide, adsorption of alachlor, acetachlor, and metolachlor on clay followed the order Ca(2+) approximately Mg(2+) < Al(3+) < or = Fe(3+), which coincided with the increasing acidity of homoionic clays. Adsorption of propachlor, however, showed an opposite dependence, suggesting a different governing interaction. In clay and humic acid mixtures, herbicide adsorption was less than that expected from independent additive adsorption by the individual constituents, and the deviation was dependent on the clay-to-humic acid ratio, with the greatest deviation consistently occurring at a 60:40 clay-to-humic acid ratio.

  10. Mineralogy of subducted clay and clay restite in the lower mantle

    Science.gov (United States)

    Armstrong, L.; Skora, S. E.; Walter, M. J.

    2012-12-01

    Seismic tomography indicates that subducting oceanic lithosphere often penetrates the transition zone and eventually the lower mantle [e.g. 1, 2]. While mineralogical changes in the mafic and ultramafic portions of slabs have been well documented experimentally, the phase relations of overlying sediments at pressures above 25 GPa remain poorly studied. This is in part because sediments are expected to partially melt at sub-arc depth (P~2.5-4.5 GPa), and contribute to the genesis of arc magmas. Sediment restites left behind after the extraction of low pressure melts undergo major chemical changes, according to the melting reaction: Coe+Phen+Cpx+H2O = Grt+Ky+Melt [3]. However, sediments may not always melt depending on the thermal regime and volatile availability and composition [3]. Hence, chemically unmodified sediments as well as restites may be entrained to greater depths and contribute to compositional heterogeneity in the deep mantle. Indeed, mineral inclusions with compositions indicative of subducted sedimentary protoliths (CAS-phase; K-hollandite; stishovite) have been reported in 'ultradeep' diamonds and suggest that deep subduction and survival of sediments occurs to at least transition zone depths [4]. With this in mind, we have performed laser heated diamond anvil cell experiments at pressures of 8-80 GPa on two anhydrous glass starting materials: a marine clay and the restite that is left after 50% melt extraction of this clay at 3 GPa and 800 °C [3]. We chose to work with an anhydrous version of the marine clay given that the investigated pressure range exceeds that of phengite stability [5], and phengite is the only hydrous phase in subducted sediments at UHP conditions. The clay was heated along a P-T path representative of a cold subduction geotherm, whereas the clay restite was heated along a hotter subduction geotherm consistent with low pressure melting. Phases were identified by synchrotron X-ray micro-diffraction at beamline I15 of the Diamond

  11. Nitrate Adsorption on Clay Kaolin: Batch Tests

    Directory of Open Access Journals (Sweden)

    Morteza Mohsenipour

    2015-01-01

    Full Text Available Soils possessing kaolin, gibbsite, goethite, and hematite particles have been found to have a natural capacity to attenuate pollution in aqueous phase. On the other hand, the hydroxyl group in soil increases anion exchange capacity under a low pH condition. The main objective of this paper was to evaluate effects of kaolin on nitrate reduction under acidic condition. In order to analyze the kaolin adsorption behaviour under various conditions, four different concentrations of nitrate, 45, 112.5, 225, and 450 mgNO3-/L, with a constant pH equal to 2, constant temperature equal to 25°C, and exposure period varying from 0 to 150 minutes were considered. The capacity of nitrate adsorption on kaolin has also been studied involving two well-known adsorption isotherm models, namely, Freundlich and Longmuir. The results revealed that approximately 25% of the nitrate present in the solution was adsorbed on clay kaolin. The laboratory experimental data revealed that Freundlich adsorption isotherm model was more accurate than Longmuir adsorption model in predicting of nitrate adsorption. Furthermore, the retardation factor of nitrate pollution in saturated zone has been found to be approximately 4 in presence of kaolin, which indicated that kaolin can be used for natural scavenger of pollution in the environment.

  12. Cobalt 60 cation exchange with mexican clays

    International Nuclear Information System (INIS)

    Nava Galve, R.G.

    1993-01-01

    Mexican clays can be used to remove radioactive elements from contaminated aqueous solutions. Cation exchange experiments were performed with 60 Co radioactive solution. In the present work the effect of contact time on the sorption of Co 2+ was studied. The contact time in hydrated montmorillonite was from 5 to 120 minutes and in dehydrated montmorillonite 5 to 1400 minutes. The Co 2+ uptake value was, in hydrated montmorillonite, between 0.3 to 0.85 m eq/g and in dehydrated montmorillonite, between 0.6 to 1.40 m eq/g. The experiments were done in a pH 5.1 to 5.7 and normal conditions. XRD patterns were used to characterize the samples. The crystallinity was determined by X-ray Diffraction and it was maintained before and after the cation exchange. DTA thermo grams showed the temperatures of the lost humidity and crystallization water. Finally, was observed that dehydrated montmorillonite adsorb more cobalt than hydrated montmorillonite. (Author)

  13. Dynamics of water confined in clay minerals

    International Nuclear Information System (INIS)

    Le Caer, S.; Pommeret, S.; Renault, J.Ph.; Lima, M.; Righini, R.; Gosset, D.; Simeone, D.; Bergaya, F.

    2012-01-01

    Ultrafast infrared spectroscopy of the O-D stretching mode of dilute HOD in H 2 O probes the local environment and the hydrogen bond network of confined water. The dynamics of water molecules confined in the interlayer space of montmorillonites (Mt) and in interaction with two types of cations (Li + and Ca 2+ ) but also with the negatively charged siloxane surface are studied. The results evidence that the OD vibrational dynamics is significantly slowed down in confined media: it goes from 1.7 ps in neat water to 2.6 Ps in the case of Li + cations with two water pseudo-layers (2.2-2.3 ps in the case of Ca 2+ cations) and to 4.7 ps in the case of Li + cations with one water pseudo-layer. No significant difference between the two cations is noticed. In this 2D confined geometry (the interlayer space being about 0.6 nm for two water pseudo-layers), the relaxation time constants obtained are comparable to the ones measured in analogous concentrated salt solutions. Nevertheless, and in strong opposition to the observations performed in the liquid phase, anisotropy experiments evidence the absence of rotational motions on a 5 ps time scale, proving that the hydrogen bond network in the interlayer space of the clay mineral is locked at this time scale. (authors)

  14. GAS PERMEABILITY OF GEOSYNTHETIC CLAY LINERS

    Directory of Open Access Journals (Sweden)

    Helena Vučenović

    2017-01-01

    Full Text Available Geosynthetic clay liners (GCL are manufactured hydraulic barriers consisting of mineral and geosynthetic components. They belong to a group of geosynthetic products whose primary purpose is to seal and they have been used in many geotechnical and hydrotechnical applications, landfi lls and liquid waste lagoons for quite a while. They are used in landfill final cover systems to prevent the infi ltration of precipitation into the landfi ll body and the penetration of gases and liquids from the landfill into the atmosphere and environment. Laboratory and fi eld research and observations on regulated landfi lls have proven the eff ectiveness of GCL as a barrier for the infi ltration of precipitation into the landfi ll body as well as the drainage of fl uid beneath the landfill. Due to the presence of high concentrations of gases in the landfill body, there is a growing interest in determining the efficiency of GCL as a gas barrier. It was not until the last twenty years that the importance of this topic was recognized. In this article, current GCL gas permeability studies, the testing methods and test results of gas permeability in laboratory conditions are described.

  15. Deformation analysis of shallow penetration in clay

    Science.gov (United States)

    Sagaseta, C.; Whittle, A. J.; Santagata, M.

    1997-10-01

    A new method of analysis is described for estimating the deformations and strains caused by shallow undrained penetration of piles and caissons in clay. The formulation combines previous analyses for steady, deep penetration, with methods used to compute soil deformations due to near-surface ground loss, and is referred to as the Shallow Strain Path Method (SSPM). Complete analytical solutions for the velocity and strain rates are given for a planar wall, an axisymmetric, closed-ended pile and unplugged, open-ended pile geometries. In these examples, the analyses consider a single source penetrating through the soil at a constant rate, generating a family of penetrometers with rounded tips, referred to as simple wall, pile and tube geometries. Soil deformations and strains are obtained by integrating the velocity and strain rates along the particle paths.The transition from shallow to deep penetration is analysed in detail. Shallow penetration causes heave at the ground surface, while settlements occur only in a thin veneer of material adjacent to the shaft and in a bulb-shaped region around the tip. The size of this region increases with the embedment depth. Deformations inside an open-ended pile/caisson are affected significantly by details of the simple tube wall geometry.

  16. Sedimentation of athermal particles in clay suspensions

    Science.gov (United States)

    Clotet, Xavier; Kudrolli, Arshad

    2015-03-01

    We discuss sedimentation of athermal particles in dense clay suspensions which appear liquid-like to glass-like. These studies are motivated by the physics important to a diverse range of problems including remediation of oil sands after the extraction of hydrocarbons, and formation of filter cakes in bore wells. We approach this problem by first considering collective sedimentation of athermal spherical particles in a viscous liquid in quasi-two dimensional and three dimensional containers. We examine the system using optical and x-ray tomography techniques which gives particle level information besides global information on the evolution of the volume fraction. Unlike sediments in the dilute limit - which can be modeled as isolated particles that sediment with a constant velocity and slow down exponentially as they approach the bottom of the container - we find interaction between the particles through the viscous fluids leads to qualitatively differences. We find significant avalanching behavior and cooperative motion as the grains collectively settle, and non-exponential increase in settling time. We discuss the effect of stirring caused by the sedimenting particles on their viscosity and consequently the sedimentation rates as a function of particle concentration. Supported by Petroleum Research Fund Grant PRF # 54045-ND9.

  17. Polypropylene–clay composite prepared from Indian bentonite

    Indian Academy of Sciences (India)

    WINTEC

    composites have recently found applications in packaging, automotive ... process using xylene as the solvent. Solvent ... Particle size distribution curve for clay, bentonite. Table 2. .... greater probability of debonding due to the poor interfa-.

  18. Stability of iron in clays under different leaching conditions

    Czech Academy of Sciences Publication Activity Database

    Doušová, B.; Fuitová, L.; Koloušek, D.; Lhotka, M.; Matys Grygar, Tomáš; Spurná, P.

    2014-01-01

    Roč. 62, 1-2 (2014), s. 145-152 ISSN 0009-8604 Institutional support: RVO:61388980 Keywords : Clays * Iron * Leaching Stability * Structure * Surface Properties Subject RIV: DD - Geochemistry Impact factor: 1.228, year: 2014

  19. Free volume sizes in intercalated polyamide 6/clay nanocomposites

    DEFF Research Database (Denmark)

    Wiinberg, P.; Eldrup, Morten Mostgaard; Pedersen, N.J.

    2005-01-01

    The effect of incorporating modified clay into a polyamide 6 (PA6) matrix, on the free volume cavity sizes and the thermal and viscoelastic properties of the resulting nanocomposite, was studied with positron annihilation lifetime spectroscopy, differential scanning calorimetry and dynamic...... response of PA6/clay nanocomposites, as compared to unfilled PA6, pointed towards a changed mobility in the non-crystalline regions. At high concentrations of clay (> 19 wt%) an increase of the free volume cavity diameter was observed, indicating a lower chain packing efficiency in the PA6/clay...... nanocomposites. The increased free volume sizes were present both above and below the glass transition temperature of PA6. (c) 2005 Elsevier Ltd. All rights reserved....

  20. Thermodynamically coupled mass transport processes in a saturated clay

    International Nuclear Information System (INIS)

    Carnahan, C.L.

    1984-01-01

    Gradients of temperature, pressure, and fluid composition in saturated clays give rise to coupled transport processes (thermal and chemical osmosis, thermal diffusion, ultrafiltration) in addition to the direct processes (advection and diffusion). One-dimension transport of water and a solute in a saturated clay subjected to mild gradients of temperature and pressure was simulated numerically. When full coupling was accounted for, volume flux (specific discharge) was controlled by thermal osmosis and chemical osmosis. The two coupled fluxes were oppositely directed, producing a point of stagnation within the clay column. Solute flows were dominated by diffusion, chemical osmosis, and thermal osmosis. Chemical osmosis produced a significant flux of solute directed against the gradient of solute concentration; this effect reduced solute concentrations relative to the case without coupling. Predictions of mass transport in clays at nuclear waste repositories could be significantly in error if coupled transport processes are not accounted for. 14 refs., 8 figs

  1. Thermodynamically coupled mass transport processes in a saturated clay

    International Nuclear Information System (INIS)

    Carnahan, C.L.

    1984-11-01

    Gradients of temperature, pressure, and fluid composition in saturated clays give rise to coupled transport processes (thermal and chemical osmosis, thermal diffusion, ultrafiltration) in addition to the direct processes (advection and diffusion). One-dimensional transport of water and a solute in a saturated clay subjected to mild gradients of temperature and pressure was simulated numerically. When full coupling was accounted for, volume flux (specific discharge) was controlled by thermal osmosis and chemical osmosis. The two coupled fluxes were oppositely directed, producing a point of stagnation within the clay column. Solute flows were dominated by diffusion, chemical osmosis, and thermal osmosis. Chemical osmosis produced a significant flux of solute directed against the gradient of solute concentration; this effect reduced solute concentrations relative to the case without coupling. Predictions of mass transport in clays at nuclear waste repositories could be significantly in error if coupled transport processes are not accounted for. 14 references, 8 figures, 1 table

  2. Clay squirt: Local flow dispersion in shale-bearing sandstones

    DEFF Research Database (Denmark)

    Sørensen, Morten Kanne; Fabricius, Ida Lykke

    2017-01-01

    Dispersion of elastic-wave velocity is common in sandstone and larger in shaly sandstone than in clean sandstone. Dispersion in fluid-saturated shaly sandstone often exceeds the level expected from the stress-dependent elastic moduli of dry sandstone. The large dispersion has been coined clay...... squirt and is proposed to originate from a pressure gradient between the clay microporosity and the effective porosity. We have formulated a simple model that quantifies the clay-squirt effect on bulk moduli of sandstone with homogeneously distributed shale laminae or dispersed shale. The model...... predictions were compared with the literature data. For sandstones with dispersed shale, agreement was found, whereas other sandstones have larger fluid-saturated bulk modulus, possibly due to partially load-bearing shales or heterogeneous shale distribution. The data that agree with the clay-squirt model...

  3. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    International Nuclear Information System (INIS)

    Liu, Hui-Hai; Rutqvist, Jonny; Zheng, Liange; Sonnenthal, Eric; Houseworth, Jim; Birkholzer, Jens

    2010-01-01

    As a result of the termination of the Yucca Mountain Project, the United States Department of Energy (DOE) has started to explore various alternative avenues for the disposition of used nuclear fuel and nuclear waste. The overall scope of the investigation includes temporary storage, transportation issues, permanent disposal, various nuclear fuel types, processing alternatives, and resulting waste streams. Although geologic disposal is not the only alternative, it is still the leading candidate for permanent disposal. The realm of geologic disposal also offers a range of geologic environments that may be considered, among those clay shale formations. Figure 1-1 presents the distribution of clay/shale formations within the USA. Clay rock/shale has been considered as potential host rock for geological disposal of high-level nuclear waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures induced by tunnel excavation. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at Mol site, Belgium (Barnichon et al., 2005) have all been under intensive scientific investigations (at both field and laboratory scales) for understanding a variety of rock properties and their relations with flow and transport processes associated with geological disposal of nuclear waste. Clay/shale formations may be generally classified as indurated and plastic clays (Tsang et al., 2005). The latter (including Boom clay) is a softer material without high cohesion; its deformation is dominantly plastic. For both clay rocks, coupled thermal, hydrological, mechanical and chemical (THMC) processes are expected to have a significant impact on the long-term safety of a clay repository. For

  4. The regeneration viability evaluation of zinc on bofe clay columns

    International Nuclear Information System (INIS)

    Araujo, A.L.P. de; Silva, M.G.C da; Gimenes, M.L.; Barros, M.A.S.D.

    2011-01-01

    In this study, the Bofe bentonite clay, calcined at 500 °C was used for removal of zinc in porous bed with multiple cycles of adsorption-desorption. The natural and calcined clay was characterized by N 2 physisorption (BET method), X-ray diffraction (XRD) and thermal analysis). The experiments for the removal of zinc were carried out at room temperature (25 °C) with particle diameter of 0.855 mm and a flow rate of 3 mL/min. The results indicated that over the four cycles of adsorption/desorption of which was submitted, the clay has not lost the capacity for adsorption of metal and that this process may be feasible to replace or complement conventional treatments to remove metals, since that clay was able to reduce the concentration of zinc to the amount recommended by Resolution Nº 357/2005 of CONAMA (5 mg.L -1 ). (author)

  5. Utilization of Nkpuma-Akpatakpa clay in ceramics: characterization ...

    African Journals Online (AJOL)

    PROF HORSFALL

    ABSTRACT: Nkpuma – Akpatakpa clay was analysed for its ceramics suitability. ... Nigeria, for their different applications (Elueze et al.,. 1999 ... ministry of Science and Technology, located in Enugu, ... et al (2014) but with little modification.

  6. Application of solar treatment for the disinfection of geophagic clays ...

    African Journals Online (AJOL)

    Elvis Fosso-Kankeu

    ... Water and Earth Science, Tshwane University of Technology, 175 Nelson Mandela ... Most of the microorganisms occurring in geophagic clays are undesirable and may .... Modified Walkley-Black (Walkey and Black, 1934) chromic acid wet.

  7. Assessment of geomechanical properties of intact Opalinus Clay - Expert report

    International Nuclear Information System (INIS)

    Amann, F.; Vogelhuber, M.

    2015-11-01

    This comprehensive report published by the Swiss Federal Nuclear Safety Inspectorate ENSI presents an expert report published on the assessment of the geomechanical properties of intact Opalinus Clay. This review report addresses the conceptual constitutive framework for repositories in Opalinus Clay. The author addresses the geomechanical fundamentals that are necessary in order to adequately judge experiments on intact Opalinus Clay and the interpretation of the results. The report assesses in detail the various test series on intact Opalinus Clay carried out along with the interpretations made by experts and NAGRA. Further assessments are quoted including those on sample geometries tested, effective strength properties, undrained shear strength properties and elastic properties. The results of work done by other experts are also presented and discussed. The report is completed with a list of relevant literature

  8. Geotechnical and physico chemical properties of clays associated ...

    African Journals Online (AJOL)

    2012-12-03

    Dec 3, 2012 ... which were later combined for the complete particle size distribution. ... leaching action of the finest materials (clay fraction) from the surface horizons ..... slopes on which the gravitational pull on the water charged soils rich in ...

  9. Immobilization of industrial waste in cement–bentonite clay matrix

    Indian Academy of Sciences (India)

    Unknown

    Immobilization of industrial waste in cement–bentonite clay matrix. I B PLECAS* and S ... high structural integrity and minimizing the risk of escape by leaching. ..... Radioactive Waste Management and Nuclear Fuel Cycle 14. 195. Plecas I ...

  10. Studies on structural properties of clay magnesium ferrite nano composite

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Manpreet, E-mail: manpreetchem@pau.edu; Singh, Mandeep [Department of Chemistry, Punjab Agricultural University, Ludhiana-141004 (India); Jeet, Kiran, E-mail: kiranjeet@pau.edu; Kaur, Rajdeep [Electron Microscopy and Nanoscience Laboratory, Punjab Agricultural University, Ludhiana-141004 (India)

    2015-08-28

    Magnesium ferrite-bentonite clay composite was prepared by sol-gel combustion method employing citric acid as complexing agent and fuel. The effect of clay on the structural properties was studied with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) Spectroscopy, Scanning electron microscopy (SEM), SEM- Energy dispersive Spectroscope (EDS) and BET surface area analyzer. Decrease in particle size and density was observed on addition of bentonite clay. The BET surface area of nano composite containing just 5 percent clay was 74.86 m{sup 2}/g. Whereas porosity increased from 40.5 per cent for the pure magnesium ferrite to 81.0 percent in the composite showing that nano-composite has potential application as an adsorbent.

  11. Comparative evaluation of clays from Abakaliki Formation with ...

    African Journals Online (AJOL)

    Okeey Aghamelu

    Department of Geology, Ebonyi State University, Abakaliki, Ebonyi State, Nigeria. ... classified as inorganic clays of high plasticity (CH) according to Unified Soil Classification System .... movement through the outcrop locations and sample.

  12. LABORATORY TESTING OF BENTONITE CLAYS FOR LANDFILL DESIGN AND CONSTRUCTION

    Directory of Open Access Journals (Sweden)

    Biljana Kovačević Zelić

    2007-12-01

    Full Text Available Top and bottom liners are one of the key construction elements in every landfill. They are usually made as compacted clay liners (CCLs composed of several layers of compacted clay with strictly defined properties or by the use of alternative materials such as: GCL – geosynthetic clay liner, BES – bentonite enhanced soils or bentonite/polymer mixtures. Following the state of the art experiences in the world, GCLs are used in Croatian landfills for several years, as well. Depending upon the location and the obeying function, GCLs have to fulfill certain conditions. A legislated compatibility criterion has to be proven by various laboratory tests. In the paper are presented the results of direct shear and chemical compatibility tests of GCLs as well as the results of permeability measurement of kaolin clay (the paper is published in Croatian .

  13. Utilization of crushed clay brick in cellular concrete production

    Directory of Open Access Journals (Sweden)

    Ali A. Aliabdo

    2014-03-01

    Full Text Available The main objective of this research program is to study the effect of using crushed clay brick as an alternative aggregate in aerated concrete. Two series of mixtures were designed to investigate the physico-mechanical properties and micro-structural analysis of autoclave aerated concrete and foamed concrete, respectively. In each series, natural sand was replaced with crushed clay brick aggregate. In both series results showed a significant reduction in unit weight, thermal conductivity and sound attenuation coefficient while porosity has increased. Improvement on compressive strength of autoclave aerated concrete was observed at a percentage of 25% and 50% replacement, while in foamed concrete compressive strength gradually decreased by increasing crushed clay brick aggregate content. A comparatively uniform distribution of pore in case of foamed concrete with natural sand was observed by scanning electron microscope, while the pores were connected mostly and irregularly for mixes containing a percentage higher than 25% clay brick aggregate.

  14. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hui-Hai; Rutqvist, Jonny; Zheng, Liange; Sonnenthal, Eric; Houseworth, Jim; Birkholzer, Jens

    2010-08-31

    As a result of the termination of the Yucca Mountain Project, the United States Department of Energy (DOE) has started to explore various alternative avenues for the disposition of used nuclear fuel and nuclear waste. The overall scope of the investigation includes temporary storage, transportation issues, permanent disposal, various nuclear fuel types, processing alternatives, and resulting waste streams. Although geologic disposal is not the only alternative, it is still the leading candidate for permanent disposal. The realm of geologic disposal also offers a range of geologic environments that may be considered, among those clay shale formations. Figure 1-1 presents the distribution of clay/shale formations within the USA. Clay rock/shale has been considered as potential host rock for geological disposal of high-level nuclear waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures induced by tunnel excavation. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at Mol site, Belgium (Barnichon et al., 2005) have all been under intensive scientific investigations (at both field and laboratory scales) for understanding a variety of rock properties and their relations with flow and transport processes associated with geological disposal of nuclear waste. Clay/shale formations may be generally classified as indurated and plastic clays (Tsang et al., 2005). The latter (including Boom clay) is a softer material without high cohesion; its deformation is dominantly plastic. For both clay rocks, coupled thermal, hydrological, mechanical and chemical (THMC) processes are expected to have a significant impact on the long-term safety of a clay repository. For

  15. Assessment of geomechanical properties of intact Opalinus Clay - Expert report

    Energy Technology Data Exchange (ETDEWEB)

    Amann, F. [Eidgenössische Technische Hochschule ETHZ, Zürich (Switzerland); Vogelhuber, M. [Dr. von Moos AG, Geotechnisches Büro, Zürich (Switzerland)

    2015-11-15

    This comprehensive report published by the Swiss Federal Nuclear Safety Inspectorate ENSI presents an expert report published on the assessment of the geomechanical properties of intact Opalinus Clay. This review report addresses the conceptual constitutive framework for repositories in Opalinus Clay. The author addresses the geomechanical fundamentals that are necessary in order to adequately judge experiments on intact Opalinus Clay and the interpretation of the results. The report assesses in detail the various test series on intact Opalinus Clay carried out along with the interpretations made by experts and NAGRA. Further assessments are quoted including those on sample geometries tested, effective strength properties, undrained shear strength properties and elastic properties. The results of work done by other experts are also presented and discussed. The report is completed with a list of relevant literature.

  16. properties of fired bodies made from tanzanian talc- clay mixes

    African Journals Online (AJOL)

    Mgina

    Furthermore, the percentage shrinkage of the fired crisp bodies was found to increase with temperature. ... mixes having the highest percentage of clay showed the highest amount of shrinkage. In general, ..... BGS Technical Report. WG /931/1.

  17. Comparative Analysis on Chemical Composition of Bentonite Clays ...

    African Journals Online (AJOL)

    2017-09-12

    Sep 12, 2017 ... Comparative Analysis on Chemical Composition of Bentonite Clays. Obtained from Ashaka and ... versatile material for geotechnical engineering and as well as their demand for ..... A PhD thesis submitted to the Chemical ...

  18. Unique morphology of dispersed clay particles in a polymer nanocomposite

    CSIR Research Space (South Africa)

    Malwela, T

    2011-02-01

    Full Text Available This communication reports a unique morphology of dispersed clay particles in a polymer nanocomposite. A nanocomposite of poly[butylene succinate)-co-adipate] (PBSA) with 3 wt% of organically modified montmorillonite was prepared by melt...

  19. Clay club catalogue of characteristics of argillaceous rocks

    International Nuclear Information System (INIS)

    2005-01-01

    The OECD/NEA Working Group on the Characterisation, the Understanding and the Performance of Argillaceous Rocks as Repository Host Formations, namely the Clay Club, examines the various argillaceous rocks that are being considered for the deep geological disposal of radioactive waste, i.e. from plastic, soft, poorly indurated clays to brittle, hard mud-stones or shales. The Clay Club considered it necessary and timely to provide a catalogue to gather in a structured way the key geo-scientific characteristics of the various argillaceous formations that are - or were - studied in NEA member countries with regard to radioactive waste disposal. The present catalogue represents the outcomes of this Clay Club initiative. (author)

  20. Control of clay minerals effect in flotation. A review

    Directory of Open Access Journals (Sweden)

    Taner Hasan Ali

    2016-01-01

    Full Text Available The increased exposure to low grade ores highlights the importance of understanding phyllosilicate gangue mineralogy which consists of common gangue minerals. To improve the flotation performance and ore quality the negative effect of the clay minerals on flotation should be identified. The presence of clay minerals leads to problems, such as changing the froth stability, which are related to swelling behaviour, increase in pulp viscosity, overconsumption of reagents, slime coating and mechanical entrainment. The clay content in the ore is changing from time to time and it is necessary to provide quick solutions to the issues caused by the new ore composition. The objective of this paper is to give an overview how to control the colloidal properties of clay minerals on flotation.

  1. CONTRAST IN CLAY MINERALOGY AND THEIR EFFECT ON ...

    African Journals Online (AJOL)

    a

    Clay minerals reduced the porosity and permeability of the Permo-Triassic sandstones. .... Lower Triassic-Lias .... and show high birefringence around the grains. ..... It is a regime after effective burial depth in which the solubility of minerals.

  2. Influence of Macro-Topography on Damage Tolerance and Fracture Toughness of 0.1 wt % Multi-Layer Graphene/Clay-Epoxy Nanocomposites

    Directory of Open Access Journals (Sweden)

    Rasheed Atif

    2016-07-01

    Full Text Available Influence of topographical features on mechanical properties of 0.1 wt % Multi-Layer Graphene (MLG/clay-epoxy nanocomposites has been studied. Three different compositions were made: (1 0.1 wt % MLG-EP; (2 0.1 wt % clay-EP and (3 0.05 wt % MLG-0.05 wt % clay-EP. The objective of making hybrid nanocomposites was to determine whether synergistic effects are prominent at low weight fraction of 0.1 wt % causing an improvement in mechanical properties. The topographical features studied include waviness (Wa, roughness average (Ra, root mean square value (Rq and maximum roughness height (Rmax or Rz. The Rz of as-cast 0.1 wt % MLG-EP, clay-EP and 0.05 wt % MLG-0.05 wt % clay-EP nanocomposites were 43.52, 48.43 and 41.8 µm respectively. A decrease in Rz values was observed by treating the samples with velvet cloth and abrasive paper 1200P while increased by treating with abrasive papers 320P and 60P. A weight loss of up to 16% was observed in samples after the treatment with the abrasive papers. It was observed that MLG is more effective in improving the mechanical properties of epoxy than nanoclay. In addition, no significant improvement in mechanical properties was observed in hybrid nanocomposites indicating that 0.1 wt % is not sufficient to generate conspicuous synergistic effects.

  3. Heteroaggregation of Silver Nanoparticles with Clay Minerals in Aqueous System

    Science.gov (United States)

    Liu, J.; Burrow, E.; Hwang, Y.; Lenhart, J.

    2013-12-01

    Nanoparticles are increasingly being used in industrial processes and consumer products that exploit their beneficial properties and improve our daily lives. Nevertheless, they also attract attention when released into natural environment due to their potential for causing adverse effects. The fate and transport of nanoparticles in aqueous systems have been the focus of intense study. However, their interactions with other natural particles have received only limited attention. Clay minerals are ubiquitous in most aquatic systems and their variably charged surfaces can act as deposition sites that can alter the fate and transport of nanoparticles in natural aqueous environments. In this study, we investigated the homoaggregation of silver nanoparticles with different coating layers and their heteroaggregation behavior with clay minerals (illite, kaolinite, montmorillonite) in neutral pH solutions. Silver nanoparticles with a nominal diameter of 80 nm were synthesized with three different surface coating layers: uncoated, citrate-coated and Tween-coated. Illite (IMt-2), kaolinite (KGa-2), and montmorillonite (SWy-2) were purchased from the Clay Mineral Society (Indiana) and pretreated to obtain monocationic (Na-clay) and dicationic (Ca-clay) suspensions before the experiments. The change in hydrodynamic diameter as a function of time was monitored using dynamic light scattering (DLS) measurements in order to evaluate early stage aggregation as a function of electrolyte concentration in both the homo- and heteroaggregation scenarios. A shift in the critical coagulation concentration (CCC) values to lower electrolyte concentrations was observed in binary systems, compared to single silver nanoparticle and clay systems. The results also suggest more rapid aggregation in binary system during the early aggregation stage when compared to the single-particle systems. The behavior of citrate-coated silver nanoparticles was similar to that of the bare particles, while the

  4. Modification of bentonite clay and application on polypropylene nano composites

    International Nuclear Information System (INIS)

    Oliveira, Akidauana D.B.; Rodrigues, Andre W.B.; Agrawal, Pankaj; Araujo, Edcleide M.; Melo, Tomas J.A.

    2009-01-01

    This work consisted on the modification of Brasgel PA clay with ionic surfactant Praepagen WB and its incorporation into polypropylene. The results of infrared and DR-X was showed that the intercalation of surfactant in the clay and the incorporation of organoclay in PP matrix resulted in the formation of an intercalated structure. The impact strength of PP increased with the incorporation of organoclay. (author)

  5. Effect of illite clay and divalent cations on bitumen recovery

    Energy Technology Data Exchange (ETDEWEB)

    Ding, X. [SNC-Lavalin Inc., Calgary, AB (Canada); Repka, C. [Baker Petrolite Corp., Fort McMurray, AB (Canada); Xu, Z.; Masliyah, J. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2006-12-15

    Nearly 35 per cent of Canada's petroleum needs can be met from the Athabasca oil sands, particularly as conventional sources of petroleum decline. The interactions between bitumen and clay minerals play a key role in the recovery process of bitumen because they affect bitumen aeration. The 2 clays minerals found in various oil sands extraction process streams are kaolinite and illite. In this study, doping flotation tests using deionized water and electrokinetic studies were performed to examine the effect of illite clays on bitumen recovery. The effect of magnesium ions was also examined and compared with calcium ions. This paper also discussed the effects of temperature and tailings water chemistry. The negative effect of illite clay on bitumen recovery was found to be associated with its acidity. Denver flotation cell measurements indicated that the addition of calcium or magnesium ions to the flotation deionized water had only a slight effect on bitumen recovery, but the co-addition of illite clay and divalent cations resulted in a dramatic reduction in bitumen recovery. The effect was more significant at lower process temperature and low pH values. Zeta potential distributions of illite suspensions and bitumen emulsions were measured individually and as a mixture to determine the effect of divalent cations on the interaction between bitumen and illite clay. The presence of 1 mM calcium or magnesium ions in deionized water had a pronounced effect on the interactions between bitumen and illite clay. Slime coating of illite onto bitumen was not observed in zeta potential distribution measurements performed in alkaline tailings water. When tests were conducted using plant recycle water, the combination of illite clay and divalent cations did not have an adverse effect on bitumen recovery. 25 refs., 3 tabs., 15 figs.

  6. Painting with Clay: A Study of the Masters

    Science.gov (United States)

    Skophammer, Karen

    2010-01-01

    Plasticine clay is a bendable material that is easily manipulated by students of all ages. It is a great material to work with because it does not dry out from day to day, so high-school students can work on an extended project. They do not have to worry about the clay drying and cracking, and the entire work of art does not have to be completed…

  7. Solar conduction heat transfer in fired clay bricks

    Energy Technology Data Exchange (ETDEWEB)

    Custodio-Garcia, E.; Andres Zarate, Esteban; Cordova, Quintiliano A. [Universidad Juarez Autonoma de Tabasco, DACB, Cunduacan, Tabasco 86680 (Mexico); Sebastian, P.J.; Campos-Alvarez, J. [CIE-UNAM, 62580 Temixco, Mor 62580 (Mexico); Trevino-Palacios, Carlos G. [Instituto Nacional de Astrofisica, Optica y Electronica. A.P. 51 Y 216. Puebla 72000 (Mexico); De la O-Leon, Hugo [Universidad Juarez Autonoma de Tabasco, DAIS, Cunduacan Tab (Mexico)

    2005-07-15

    When somebody is interested in building a house in the year-round-hot and humid regions, faces with the decision of using modern construction block material or the traditional red fired clay brick material. We performed mechanical and thermal controlled measurements on walls made using both materials. We found that the ancient tradition of using fired clay bricks, for the weather conditions in central Tabasco, represents an excellent alternative in cost and energy savings for construction.

  8. Synthesis, thermal properties and applications of polymer-clay nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Meneghetti, Paulo [Chemical Engineering Department, Case Western Reserve University, 10900 Euclid Ave. Cleveland, OH 44106 (United States); Qutubuddin, Syed [Chemical Engineering Department, Case Western Reserve University, 10900 Euclid Ave. Cleveland, OH 44106 (United States)]. E-mail: sxq@case.edu

    2006-03-15

    Polymer-clay nanocomposites constitute a new class of materials in which the polymer matrix is reinforced by uniformly dispersed inorganic particles (usually 10 wt.% or less) having at least one dimension in the nanometer scale. Nanocomposites exhibit improved properties when compared to pure polymer or conventional composites, such as enhanced mechanical and thermal properties, reduced gas permeability, and improved chemical stability. In this work, the synthesis of poly(methyl methacrylate) (PMMA)/clay nanocomposites is described via two methods: in situ and emulsion polymerization. The in situ technique follows a two-step process: ion-exchange of the clay to make it hydrophobic, and polymerization after dispersing the functionalized clay in the monomer. The emulsion technique combines the two steps of the in situ method into one by conducting ion-exchange and polymerization in an aqueous medium in the same reactor. The clay (montmorillonite, MMT) is functionalized with a zwitterionic surfactant, octadecyl-dimethyl betaine (C18DMB). Partially exfoliated nanocomposite, observed by transmission electron microscopy (TEM), was obtained by emulsion polymerization with 10 wt.% clay. Glass transition temperature (T {sub g}) of this nanocomposite was 18 deg. C higher than pure PMMA. With the same clay content, in situ polymerization produced intercalated nanocomposite with T {sub g} 10 deg. C lower than the emulsion nanocomposite. The storage modulus of partially exfoliated nanocomposite was superior to the intercalated structure and to the pure polymer. Using nanocomposite technology, novel PMMA nanocomposite gel electrolytes were synthesized exhibiting improved ionic conductivity and stable lithium interfacial resistance. Nanocomposites can also be used for gas storage and packaging applications as demonstrated by high barrier polymer-clay films.

  9. Synthesis, thermal properties and applications of polymer-clay nanocomposites

    International Nuclear Information System (INIS)

    Meneghetti, Paulo; Qutubuddin, Syed

    2006-01-01

    Polymer-clay nanocomposites constitute a new class of materials in which the polymer matrix is reinforced by uniformly dispersed inorganic particles (usually 10 wt.% or less) having at least one dimension in the nanometer scale. Nanocomposites exhibit improved properties when compared to pure polymer or conventional composites, such as enhanced mechanical and thermal properties, reduced gas permeability, and improved chemical stability. In this work, the synthesis of poly(methyl methacrylate) (PMMA)/clay nanocomposites is described via two methods: in situ and emulsion polymerization. The in situ technique follows a two-step process: ion-exchange of the clay to make it hydrophobic, and polymerization after dispersing the functionalized clay in the monomer. The emulsion technique combines the two steps of the in situ method into one by conducting ion-exchange and polymerization in an aqueous medium in the same reactor. The clay (montmorillonite, MMT) is functionalized with a zwitterionic surfactant, octadecyl-dimethyl betaine (C18DMB). Partially exfoliated nanocomposite, observed by transmission electron microscopy (TEM), was obtained by emulsion polymerization with 10 wt.% clay. Glass transition temperature (T g ) of this nanocomposite was 18 deg. C higher than pure PMMA. With the same clay content, in situ polymerization produced intercalated nanocomposite with T g 10 deg. C lower than the emulsion nanocomposite. The storage modulus of partially exfoliated nanocomposite was superior to the intercalated structure and to the pure polymer. Using nanocomposite technology, novel PMMA nanocomposite gel electrolytes were synthesized exhibiting improved ionic conductivity and stable lithium interfacial resistance. Nanocomposites can also be used for gas storage and packaging applications as demonstrated by high barrier polymer-clay films

  10. Clay pigments as indicators of paint authenticity and material provenance

    Czech Academy of Sciences Publication Activity Database

    Bezdička, Petr; Grygar, Tomáš; Hradil, David; Hradilová, J.

    2004-01-01

    Roč. 4, S (2004), s. 13 ISSN 0365-8066. [Mid-European Clay Conference /2./. Miskolc, 20.09.2004-24.09.2004] R&D Projects: GA MŠk LN00A028; GA ČR GA203/04/2091 Institutional research plan: CEZ:AV0Z4032918 Keywords : earthy pigments * clay minerals * microanalysis Subject RIV: CA - Inorganic Chemistry

  11. Clay ground in paintings: from Northern to Southern Europe

    DEFF Research Database (Denmark)

    Buti, David; Vila, Anna; Haack Christensen, Anne

    The use of clay grounds containing quartz was first observed in the Netherlands in artworks from Rembrandt’s workshop after 1640 [1, 2]. In addition, contemporary written sources outside the Netherlands mention this practice in Italy and Spain [2]. However, the reason for using clay as a constitu...... in Rembrandt´s workshop and in paintings by his contemporaries", in E. van de Wetering et al. A Corpus of Rembrandt Paintings, 2011, 318-334 + 660-677. Springer, Dordrecht...

  12. Homogeneity vs. Heterogeneity of Porosity in Boom Clay

    International Nuclear Information System (INIS)

    Hemes, Susanne; Desbois, Guillaume; Urai, Janos L.; De Craen, Mieke; Honty, Miroslav

    2013-01-01

    Microstructural investigations on Boom Clay at nano- to micrometer scale, using BIB-SEM methods, result in porosity characterization for different mineral phases from direct observations on high resolution SE2-images of representative elementary areas (REAs). High quality, polished surfaces of cross-sections of ∼ 1 mm 2 size were produced on three different samples from the Mol-Dessel research site (Belgium). More than 33,000 pores were detected, manually segmented and analyzed with regard to their size, shape and orientation. Two main pore classes were defined: Small pores (< 500 nm (ED)) within the clay matrices of samples and =big' pores (> 500 nm (ED)) at the interfaces between clay and non-clay mineral (NCM) grains. Samples investigated show similar porosities regarding the first pore-class, but differences occur at the interfaces between clay matrix and NCM grains. These differences were interpreted to be due to differences in quantitative mineralogy (amount of non-clay mineral grains) and grain-size distributions between samples investigated. Visible porosities were measured as 15 to 17 % for samples investigated. Pore-size distributions of pores in clay are similar for all samples, showing log-normal distributions with peaks around 60 nm (ED) and more than 95 % of the pores being smaller than 500 nm (ED). Fitting pore-size distributions using power-laws with exponents between 1.56 and 1.7, assuming self-similarity of the pore space, thus pores smaller than the pore detection resolution following the same power-laws and using these power-laws for extrapolation of pore-size distributions below the limit of pore detection resolution, results in total estimated porosities between 20 and 30 %. These results are in good agreement with data known from Mercury Porosimetry investigations (35-40 % porosity) and water content porosity measurements (∼ 36 %) performed on Boom Clay. (authors)

  13. Towards an assessment of colloid transport in undisturbed clay stone

    International Nuclear Information System (INIS)

    Durce, D.; Landesman, C.; Grambow, B.; Giffaut, E.

    2010-01-01

    Document available in abstract form only. Full text of publication follows: Colloids are known as a potentially important transport vector for sparingly soluble radionuclides in natural water environments. For assessing the mass transfer resistance of the Callovo-Oxfordian clay rock formation for colloid transport, a series of percolation experiments have been performed, using high pressure stainless steel advection cells of different diameters containing clay cores machined to about 50 μm of accuracy to the inner diameter of the cells. Synthetic clay pore water was pushed by a high pressure syringe pump across the clay core. In order to assess the cut-off size for colloid transport, molecules of different molecular weight were injected. C 14 labeled polymaleic acid (PMA) of sizes of 2 and 50 kDa were used. The effect of clay permeability, of water flow rate (injection pressure) and of ionic strength was studied. Low ionic strength experiments (I = 0.001) were realized by replacing the pore water by advective displacement with the required composition. Clay rock permeabilities were between 10 -12 and 10 -14 m/s. Hydrodynamic parameters were determined by HTO and 36 Cl injection. The results show already at 2 kDa and a permeability of 10 -12 m/s strong retention by partial filtration. The experimental results were modeled using simple chromatographic theory. (authors)

  14. Controlling harmful algae blooms using aluminum-modified clay.

    Science.gov (United States)

    Liu, Yang; Cao, Xihua; Yu, Zhiming; Song, Xiuxian; Qiu, Lixia

    2016-02-15

    The performances of aluminum chloride modified clay (AC-MC), aluminum sulfate modified clay (AS-MC) and polyaluminum chloride modified clay (PAC-MC) in the removal of Aureococcus anophagefferens were compared, and the potential mechanisms were analyzed according to the dispersion medium, suspension pH and clay surface charges. The results showed that AC-MC and AS-MC had better efficiencies in removing A.anophagefferens than PAC-MC. The removal mechanisms of the three modified clays varied. At optimal coagulation conditions, the hydrolysates of AC and AS were mainly monomers, and they transformed into Al(OH)3(am) upon their addition to algae culture, with the primary mechanism being sweep flocculation. The PAC mainly hydrolyzed to the polyaluminum compounds, which remained stable when added to the algae culture, and the flocculation mainly occurred through polyaluminum compounds. The suspension pH significantly influenced the aluminum hydrolysate and affected the flocculation between the modified clay and algae cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Interphase vs confinement in starch-clay bionanocomposites.

    Science.gov (United States)

    Coativy, Gildas; Chevigny, Chloé; Rolland-Sabaté, Agnès; Leroy, Eric; Lourdin, Denis

    2015-03-06

    Starch-clay bionanocomposites containing 1-10% of natural montmorillonite were elaborated by melt processing in the presence of water. A complex macromolecular dynamics behavior was observed: depending on the clay content, an increase of the glass transition temperature and/or the presence of two overlapped α relaxation peaks were detected. Thanks to a model allowing the prediction of the average interparticle distance, and its comparison with the average size of starch macromolecules, it was possible to associate these phenomena to different populations of macromolecules. In particular, it seems that for high clay content (10%), the slowdown of segmental relaxation due to confinement of the starch macromolecules between the clay tactoïds is the predominant phenomenon. While for lower clay contents (3-5%), a significant modification of chain relaxation seems to occur, due to the formation of an interphase by the starch macromolecules in the vicinity of clay nanoparticles coexisting with the bulk polymer. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Adsorption of hydrogen gas and redox processes in clays.

    Science.gov (United States)

    Didier, Mathilde; Leone, Laura; Greneche, Jean-Marc; Giffaut, Eric; Charlet, Laurent

    2012-03-20

    In order to assess the adsorption properties of hydrogen gas and reactivity of adsorbed hydrogen, we measured H(2)(g) adsorption on Na synthetic montmorillonite-type clays and Callovo-Oxfordian (COx) clayrock using gas chromatography. Synthetic montmorillonites with increasing structural Fe(III) substitution (0 wt %, 3.2 wt %, and 6.4 wt % Fe) were used. Fe in the synthetic montmorillonites is principally present as structural Fe(III) ions. We studied the concomitant reduction of structural Fe(III) in the clays using (57)Fe Mössbauer spectrometry. The COx, which mainly contains smectite/illite and calcite minerals, is also studied together with the pure clay fraction of this clayrock. Experiments were performed with dry clay samples which were reacted with hydrogen gas at 90 and 120 °C for 30 to 45 days at a hydrogen partial pressure close to 0.45 bar. Results indicate that up to 0.11 wt % of hydrogen is adsorbed on the clays at 90 °C under 0.45 bar of relative pressure. (57)Fe Mössbauer spectrometry shows that up to 6% of the total structural Fe(III) initially present in these synthetic clays is reduced upon adsorption of hydrogen gas. No reduction is observed with the COx sample in the present experimental conditions.

  17. Role of interlayer hydration in lincomycin sorption by smectite clays.

    Science.gov (United States)

    Wang, Cuiping; Ding, Yunjie; Teppen, Brian J; Boyd, Stephen A; Song, Cunyi; Li, Hui

    2009-08-15

    Lincomycin, an antibiotic widely administered as a veterinary medicine, is frequently detected in water. Little is known about the soil-water distribution of lincomycin despite the fact that this is a major determinant of its environmental fate and potential for exposure. Cation exchange was found to be the primary mechanism responsible for lincomycin sorption by soil clay minerals. This was evidenced by pH-dependent sorption, and competition with inorganic cations for sorptive sites. As solution pH increased, lincomycin sorption decreased. The extent of reduction was consistent with the decrease in cationic lincomycin species in solution. The presence of Ca2+ in solution diminished lincomycin sorption. Clay interlayer hydration status strongly influenced lincomycin adsorption. Smectites with the charge deficit from isomorphic substitution in tetrahedral layers (i.e., saponite) manifest a less hydrated interlayer environment resulting in greater sorption than that by octahedrally substituted clays (i.e., montmorillonite). Strongly hydrated exchangeable cations resulted in a more hydrated clay interlayer environment reducing sorption in the order of Ca- smectite. X-ray diffraction revealed that lincomycin was intercalated in smectite clay interlayers. Sorption capacity was limited by clay surface area rather than by cation exchange capacity. Smectite interlayer hydration was shown to be a major, yet previously unrecognized, factor influencing the cation exchange process of lincomycin on aluminosilicate mineral surfaces.

  18. Summary and conclusions of the faults-in-clay project

    International Nuclear Information System (INIS)

    Hallam, J.R.; Brightman, M.A.; Jackson, P.D.; Sen, M.A.

    1992-01-01

    This report summarises a research project carried out by the British Geological Survey, in cooperation with ISMES of Italy, into the geophysical detection of faults in clay formations and the determination of the hydrogeological effects of such faults on the groundwater flow regime. Following evaluation of potential research sites, an extensive programme of investigations was conducted at Down Ampney, Gloucester, where the Oxford Clay formation is underlain by the aquifers of the Great Oolite Limestone group. A previously unknown fault of 50 m throw was identified and delineated by electrical resistivity profiling; the subsequent development of a technique utilising measurements of total resistance improved the resolution of the fault 'location' to an accuracy of better than one metre. Marked anisotropy of the clay resistivities complicates conventional geophysical interpretation, but gives rise to a characteristic anomaly across the steeply inclined strata in the fault zone. After exploratory core drilling, an array of 13 boreholes was designed and completed for cross-hole seismic tomography and hydrogeological measurement and testing. The groundwater heads in the clays were found to be in disequilibrium with those in the aquifers, as a result of water supply abstraction. The indication is that the hydraulic conductivity of the fault zone is higher than that of the surrounding clay by between one and two orders of magnitude. Methodologies for the general investigation of faults in clay are discussed. (Author)

  19. Adsorption of zinc and lead on clay minerals

    Directory of Open Access Journals (Sweden)

    Katarína Jablonovská

    2006-12-01

    Full Text Available Clays (especially bentonite, zeolite and quartz sand are widely used as landfill barriers to prevent contamination of subsoil and groundwater by leachates containing heavy metals. The sorption of zinc and lead on these clays was studied as a function of time and it was found that the initial 1 h our was sufficient to exchange most of the metal ions. The retention efficiency of clay samples of Zn2+ and Pb2+ follows the order of bentonite > zeolite> quartz sand. Whatever the clay sample, lead is retained more than zinc. The concentration of elements in the solution was followed by atomic adsorption spectrofotometry. Bacillus cereus and Bacillus pumilus, previously isolated from the kaoline deposit Horna Prievrana was added into the clay samples to comparise the accumulation of Zn2+ and Pb2+ from the model solution. The study of heavy metal adsorption capacity of bacteria- enriched clay adsorbent showed a high retention efficiency for lead ions as comparised with zinc ions. Biosorption is considered a potential instrument for the removal of metals from waste solutions and for the precious metals recovery as an alternative to the conventional processes.

  20. Assessment of clay stiffness and strength parameters using index properties

    Directory of Open Access Journals (Sweden)

    Sayed M. Ahmed

    2018-06-01

    Full Text Available A new approach is developed to determine the shear wave velocity in saturated soft to firm clays using measurements of the liquid limit, plastic limit, and natural water content with depth. The shear wave velocity is assessed using the site-specific variation of the natural water content with the effective mean stress. Subsequently, an iterative process is envisaged to obtain the clay stiffness and strength parameters. The at-rest earth pressure coefficient, as well as bearing capacity factor and rigidity index related to the cone penetration test, is also acquired from the analyses. Comparisons are presented between the measured clay parameters and the results of corresponding analyses in five different case studies. It is demonstrated that the presented approach can provide acceptable estimates of saturated clay stiffness and strength parameters. One of the main privileges of the presented methodology is the site-specific procedure developed based on the relationships between clay strength and stiffness parameters, rather than adopting direct correlations. Despite of the utilized iterative processes, the presented approach can be easily implemented using a simple spreadsheet, benefiting both geotechnical researchers and practitioners. Keywords: Soft to firm clays, Atterberg limits, Shear wave velocity, Small-strain shear modulus, Constrained modulus, Undrained shear strength, Effective friction angle, Cone penetration test

  1. Facts and features of radionuclide migration in Boom Clay

    International Nuclear Information System (INIS)

    De Regge, P.; Henrion, P.; Monsecour, M.; Put, M.

    1988-01-01

    The evolution which took place during ten years of research on the behaviour of radionuclides in Boom Clay is described. Initially, the Boom Clay was regarded as a chemically inert exchanger and the radiochemical research aimed at determining the distribution of cations between the clay and some liquid phases. The observation that Boom Clay deteriorates in contact with air and loses important intrinsic properties formed a major breakthrough in the research and led to a careful examination of the real in-situ conditions. Efforts devoted to the understanding of the chemical factors pertaining to the pH, the redox potential, the extent of the buffering capacity of FeS 2 and CaCO 3 in equilibrium with the interstitial aqueous phase are reviewed. Also emerging from the overall picture was the role of the organic material present in the Boom Clay. In contrast to the water percolating fractured formations which may not be in equilibrium with the rock, the interstitial aqueous phase is completely in equilibrium with Boom Clay mainly because of its low permeability and the large excesses of buffering components. As the retention mechanisms are better understood, a more coherent picture is obtained from distribution and diffusion experiments and the effects of consolidation are being investigated in detail. 23 refs.; 4 figs.; 3 tabs

  2. Clay minerals in sandstone uranium deposits: radwaste applications

    International Nuclear Information System (INIS)

    Brookins, D.G.

    1990-01-01

    Clay minerals play an important role in the genesis of uranium deposits in sandstones. They incorporate the rate earths (REE), U, Sb, Th, Cs, Rb, Sr, Y, Ba, and even small amounts of chalcophiles. These minerals possess analog elements for many of the radwaste fission products as well as actinides and some actinide daughters. In sandstone uranium deposits, clay minerals are also associated with sulfide minerals, usually pyrite, and organic carbonaceous matter. The primary clay minerals are usually smectites, illites, chlorites and mixed layer varieties. The integrity of these clay minerals is demonstrated by their retention of formational-mineralization ages determined by Rb-Sr geochronologic investigation of the Grants Mineral Belt of the United States. The importance of the clay minerals as analog for parts of the multi-barrier concept in radwaste disposal is their ability to impede water penetration into - and movement of key elements out of uranium rich zones. The clay minerals further sorb and in other ways incorporate into their structures many fission products and actinide analogs from man-made nuclear wastes. 22 refs., 1 fig., 3 tabs

  3. Fixing of heavy metals by some inflated Tunisian clays

    International Nuclear Information System (INIS)

    Gharsalli, Jamel

    2009-01-01

    At the time of discharge of the water polluted in a natural environment and thanks to the properties of retention, adsorption and exchange of ions, clays constitute a natural barrier which will be able to limit the toxicity and the propagation of the pollutants. To contribute to the development of clays layers of Tunisia in the field of water treatments, we undertook with a mineralogical and physicochemical characterization of some inflating clays. The characteristics of these clays will be exploited for the study of the retention by adsorption of some heavy metals. The isotherms of adsorption, of heavy metals in aqueous solution by these natural clays before and after acid activation, are studied. The influence of several parameters on the fixing of heavy metals on clay such as the factors relating to the medium of adsorption (agitation, pH, time of contact, temperature. etc) and those relating to the adsorbent (mass, granulometry, impurities. etc) was studied in order to optimize the operating conditions of adsorptions.

  4. Probabilistic Description of a Clay Site using CPTU tests

    DEFF Research Database (Denmark)

    Andersen, Sarah; Lauridsen, Kristoffer; Nielsen, Benjaminn Nordahl

    2012-01-01

    A clay site at the harbour of Aarhus, where numerous cone penetration tests have been conducted, is assessed. The upper part of the soil deposit is disregarded, and only the clay sections are investigated. The thickness of the clay deposit varies from 5 to 6 meters, and is sliced into sections of...... a geotechnical assessment of a site, using both the method for classifying soil behaviour types and applying statistics, yield a new level of information, and certainty about the estimates of the strength parameters which are the important outcome of such a site description.......A clay site at the harbour of Aarhus, where numerous cone penetration tests have been conducted, is assessed. The upper part of the soil deposit is disregarded, and only the clay sections are investigated. The thickness of the clay deposit varies from 5 to 6 meters, and is sliced into sections of 1...... meter in thickness. For each slice, a map of the variation of the undrained shear strength is created through Kriging and the probability of finding weak zones in the deposit is calculated. This results in a description of the spatial variation of the undrained shear strength at the site. Making...

  5. Effects of clay-seam behavior on WIPP repository design

    International Nuclear Information System (INIS)

    Stone, C.M.; Krieg, R.D.; Branstetter, L.J.

    1981-07-01

    The geology at the southeastern New Mexico WIPP site consists of bedded layers of rock salt, anhydrite, polyhalite, mixtures of those materials, and thin clay seams. In spite of their very small (0.005 m to 0.05 m) thickness, clay seams are important to structural characterization of the WIPP stratigraphy since slip might possibly take place across them. Results of a study to determine the effects of clay seam frictional slip on the closure of a well-defined drift configuration are described. A Mohr-Coulomb dry friction model was used to model the active clay seams. The main thrust of the study was to determine the effects of friction coefficient variability on drift closure. Results show that the drift closure varies by a factor of 3.0 over the range of friction coefficients studied. The maximum slip observed along any clay seam was 0.12 m. For values of μ > .7, virtually no slip occurs along any clay seam

  6. Industrial testing of modified clay powders by the ''Permneft''' organization

    Energy Technology Data Exchange (ETDEWEB)

    Matytsyn, V I; Kosivchenko, A M; Ryabchenko, V I; Shishov, V A

    1980-01-01

    VNIIKRneft' has developed a modified clay powder based on Cherkask bentonite with one ton of solution resulting in 20-28 cubic meters of powder per TU 39-08-123-77 formula. The modification stems from the type of bentonite treatment used. Bentonite is used in the amount of 3-5% of the total mass and the treatment involves the use of 0.3% calcium soda, copolymer methacrylic acid with M-14VV methacrylate. These reagents induce processes of change within the clay. The carbonate-nitrate activity serves to penthiatize the clay particles and the reagent solution which accompany the process of coagulation in the polymer structure, and in turn, increases the incidence of viscosity in the newly emerging systems. Tests indicate that the use of modified clay powder enhances drill bit pass-through. The large quantity of drilling solution resulting from one ton of modified clay powder further enhances the practical aspects of this system and reduces overall expenditures for solution treatment and clay powder while permitting the reduction of expenditures for other chemical reagents. Such economic benefits have been confirmed by industrial testing.

  7. Evaluation of Nitrate Transport in Clay Soil

    Directory of Open Access Journals (Sweden)

    Morteza Seyedian

    2016-09-01

    Full Text Available  Background and purpose: With the increase in world population and the need to provide food, farmers are now using a variety of chemical fertilizers, organic pesticides have turned. Indiscriminate use of these inputs without considering its side effects, both environmental problems and brings in terms of human health. Among these, organic fertilizers contain soluble compounds such as nitrate. These compounds through precipitation or irrigation of the soil solution, groundwater and surface water resources are. The purpose of this study was to determine the amount of nitrate transport in clay and simulation software using HYDRUS2D. Methods: In order to perform it, 5 different height of soil column 20, 40, 60, 80 and 100 cm selected. In thicknesses of 20, 40, 60 and 80 cm respectively output levels after a period of 6, 12, 18 and 22 hours to input the concentration of nitrate (50 mg/lit is. In thicknesses of 20, 40, 60 and 80 cm, respectively, after the time of 5/6, 5/12, 21, and 25-hour concentration of 50 mg/lit is output. In thickness 20, 40, 60 and 80cm, outlet concentration after 6, 12, 18 and 22 minutes inlet concentration (50mg/lit. Results: The result showed that Hydrus software ability of simulates nitrate movement in soil and result of Hydrus software and laboratory data near. Conclusions: With increasing soil thickness difference HYDRUS2D results and experimental data more and more time to transfer nitrate were spent with increasing thickness. 

  8. Induced polarization of clay-sand mixtures: experiments and modeling

    International Nuclear Information System (INIS)

    Okay, G.; Leroy, P.; Tournassat, C.; Ghorbani, A.; Jougnot, D.; Cosenza, P.; Camerlynck, C.; Cabrera, J.; Florsch, N.; Revil, A.

    2012-01-01

    Document available in extended abstract form only. Frequency-domain induced polarization (IP) measurements consist of imposing an alternative sinusoidal electrical current (AC) at a given frequency and measuring the resulting electrical potential difference between two other non-polarizing electrodes. The magnitude of the conductivity and the phase lag between the current and the difference of potential can be expressed into a complex conductivity with the in-phase representing electro-migration and a quadrature conductivity representing the reversible storage of electrical charges (capacitive effect) of the porous material. Induced polarization has become an increasingly popular geophysical method for hydrogeological and environmental applications. These applications include for instance the characterization of clay materials used as permeability barriers in landfills or to contain various types of contaminants including radioactive wastes. The goal of our study is to get a better understanding of the influence of the clay content, clay mineralogy, and pore water salinity upon complex conductivity measurements of saturated clay-sand mixtures in the frequency range ∼1 mHz-12 kHz. The complex conductivity of saturated unconsolidated sand-clay mixtures was experimentally investigated using two types of clay minerals, kaolinite and smectite in the frequency range 1.4 mHz - 12 kHz. Four different types of samples were used, two containing mainly kaolinite (80% of the mass, the remaining containing 15% of smectite and 5% of illite/muscovite; 95% of kaolinite and 5% of illite/muscovite), and the two others containing mainly Na-smectite or Na-Ca-smectite (95% of the mass; bentonite). The experiments were performed with various clay contents (1, 5, 20, and 100% in volume of the sand-clay mixture) and salinities (distilled water, 0.1 g/L, 1 g/L, and 10 g/L NaCl solution). In total, 44 saturated clay or clay-sand mixtures were prepared. Induced polarization measurements

  9. Interaction and transport of actinides in natural clay rock with consideration of humic substances and clay organic compounds

    International Nuclear Information System (INIS)

    Marquardt, C.M.

    2012-01-01

    The present report summarizes the progress and the results obtained within the BMWi financed Joint Research Project Interaction and Transport of Actinides in Natural Clay Rock with Consideration of Humic Substances and Clay Organic Compounds. The basic approach of the work was to obtain a fundamental process understanding on the molecular level of complexation and sorption reactions as well as diffusion processes. The experimental findings are supported by quantum mechanical modeling.

  10. The Physical Behavior of Stabilised Soft Clay by Electrokinetic Stabilisation Technology

    Science.gov (United States)

    Azhar, A. T. S.; Nordin, N. S.; Azmi, M. A. M.; Embong, Z.; Sunar, N.; Hazreek, Z. A. M.; Aziman, M.

    2018-04-01

    Electrokinetic Stabilisation (EKS) technology is the combination processes of electroosmosis and chemical grouting. This technique is most effective in silty and clayey soils where the hydraulic conductivity is very low. Stabilising agents will assist the EKS treatment by inducing it into soil under direct current. The movement of stabilising agents into soil is governed by the principle of electrokinetics. The aim of this study is to evaluate the physical behavior of soft soil using the EKS technology as an effective method to strengthen soft clay soils with calcium chloride (CaCl2) as the stabilising agent. Stainless steel plates were used as the electrodes, while 1.0 mol/l of CaCl2 was used as the electrolyte that fed at the anode compartment. Soft marine clay at Universiti Tun Hussein Onn Malaysia was used as the soil sample. The EKS treatment was developed at Research Centre for Soft Soil (RECESS), UTHM with a constant voltage gradient (50 V/m) in 21 days. The result shows that the shear strength of treated soil was increased across the soil sample. The treated soil near the cathode showed the highest value of shear strength (24.5 – 33 kPa) compared with the anode and in the middle of the soil sample.

  11. Effects of acid treatment on the clay palygorskite: XRD, surface area, morphological and chemical composition

    Energy Technology Data Exchange (ETDEWEB)

    Xavier, Katiane Cruz Magalhaes; Santos, Maria do Socorro Ferreira dos; Santos, Maria Rita Morais Chaves; Oliveira, Marilia Evelyn Rodrigues; Osajima, Josy Antevelli; Silva Filho, Edson Cavalcanti da [Universidade Federal do Piaui (UFPI), Teresina, PI (Brazil); Carvalho, Maria Wilma Nunes Cordeiro, E-mail: edsonfilho@ufpi.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2014-08-15

    The palygorskite is an aluminum-magnesium silicate that has a fibrous morphology. Their physicochemical characteristics are the result of high surface area, porosity and thermal resistance which make it an attractive adsorbent. Its adsorption capacity can be increased through chemical reactions and/or heat treatments. The objective of this work is to verify the effects of acid activation on the palygorskite, treated with HCl at 90 °C at concentrations of 2, 4 and 6 mol L{sup -1} in 2 and 4 hours, with clay/acid solution ratio 1 g 10 mL{sup -1} and characterized by techniques: XRF, XRD and surface area. A significant increase in specific surface area was observed in the sample treated with HCl at the concentration 6 mol L{sup -1}. The changes were more pronounced at stricter concentrations of acidity, with decreasing intensity of reflection of the clay indicated in the XRD. These changes were confirmed in the XRF with the leaching of some oxides and with increasing concentration of SiO{sub 2}. (author)

  12. Thermo-mechanical constitutive modeling of unsaturated clays based on the critical state concepts

    OpenAIRE

    Tourchi, Saeed; Hamidi, Amir

    2015-01-01

    A thermo-mechanical constitutive model for unsaturated clays is constructed based on the existing model for saturated clays originally proposed by the authors. The saturated clays model was formulated in the framework of critical state soil mechanics and modified Cam-clay model. The existing model has been generalized to simulate the experimentally observed behavior of unsaturated clays by introducing Bishop's stress and suction as independent stress parameters and modifying the hardening rul...

  13. Developments in modelling of thermohydro-geomechanical behaviour of Boom clay and clay-based buffer materials (Volume 1)

    International Nuclear Information System (INIS)

    Baldi, G.; Hueckel, T.; Peano, A.; Pellegrini, R.

    1991-01-01

    The results of two years of research on thermomechanics of clays performed within CEC contract Fl1W/0150 are described herein. Previous studies (research contracts with CEC/WAS/380.83.7 l) performed by ISMES have evidenced the need for an improved modelling of the volumetric response of natural clays. In a coupled approach, this leads to an improved prediction of pore-pressure development and dissipation. This is crucial for assessing conditions of a possible local thermal failure as verified in laboratory tests done at ISMES. The first part of the study lays the foundations of a comprehensive theoretical treatment of the interaction between water and soil skeleton. It consists in: (a) developing a framework for inclusion of water/soil particle thermally induced interaction into a thermodynamically consistent mixture theory approach (Section 2); (b) studying possible modelling approaches of considering the effective thermal expansion coefficient of pore water dependency on pore water status (Section 2); (c) testing artificial clays to assess pore water thermal expansion dependence on temperature in the presence of different amounts of active clay minerals and also Boom clay (Section 3); (d) performing a laboratory test campaign on Boom clay with special attention to the response in the overconsolidated domain (Section 4). 89 figs., 18 tabs., 102 refs

  14. Clay-Alcohol-Water Dispersions: Anomalous Viscosity Changes Due to Network Formation of Clay Nanosheets Induced by Alcohol Clustering.

    Science.gov (United States)

    Kimura, Yuji; Haraguchi, Kazutoshi

    2017-05-16

    Clay-alcohol-water ternary dispersions were compared with alcohol-water binary mixtures in terms of viscosity and optical absorbance. Aqueous clay dispersions to which lower alcohols (ethanol, 1-propanol, 2-propanol, and tert-butanol) were added exhibited significant viscosity anomalies (maxima) when the alcohol content was 30-55 wt %, as well as optical absorbance anomalies (maxima). The maximum viscosity (η max ) depended strongly on the clay content and varied between 300 and 8000 mPa·s, making it remarkably high compared with the viscosity anomalies (2 mPa·s) observed in alcohol-water binary mixtures. The alcohol content at η max decreased as the hydrophobicity of the alcohol increased. The ternary dispersions with viscosity anomalies exhibited thixotropic behaviors. The effects of other hydrophilic solvents (glycols) and other kinds of clays were also clarified. Based on these findings and the average particle size changes, the viscosity anomalies in the ternary dispersions were explained by alcohol-clustering-induced network formation of the clay nanosheets. It was estimated that 0.9, 1.7, and 2.5 H 2 O molecules per alcohol molecule were required to stabilize the ethanol, 2-propanol, and tert-butanol, respectively, in the clay-alcohol-water dispersions.

  15. Developments in modelling of thermohydro-geomechanical behaviour of Boom clay and clay-based buffer materials (volume 2)

    International Nuclear Information System (INIS)

    Baldi, G.; Hueckel, T.; Peano, A.; Pellegrini, R.

    1991-01-01

    This study is composed of two parts: The first part (Volume 1) lays the foundations of a comprehensive theoretical treatment of the interaction between water and soil skeleton during thermal dilatation. The second part (volume 2) is devoted to the development and the application of advance constitutive modelling of mechanical behaviour of clays taking into account the extensive tests of Boom clay reported in the first volume. The development concentrated on the improvement of prediction of the volumetric response of clay skeleton: (a) improving the dilatancy prediction at low to high overconsolidation ratios (Section 2). An elasto-plastic constitutive model has been developed to account for this effect (Section 3.2.); (b) modelling of swelling effects (Section 2.5). A preliminary interpretative model for swelling prediction has been developed (Section 2.5). The application part consisted in interpreting the experimental results obtained for Boom clay to calibrate a set of constants (Section 3) for performing numerical analyses (Section 4) for the thermomechanical model already calibrated for Boom clay (Appendix). Interpretation of the tests required an assessment of influence of the strong anisotropy effects revealed by Boom clay on the basis of an interpretative model characterized by a kinematic hardening plasticity and coupled elasticity (section 3)

  16. Chemo-hydro-mechanical behaviour of unsaturated clays

    International Nuclear Information System (INIS)

    Mokni, N.; Olivella, S.; Alonso, E.E.; Romero, E.

    2010-01-01

    Document available in extended abstract form only. Understanding of the chemical effects on clays is essential for many problems ranging from pollution studies and waste-containment. Several studies examined the effect of changes in pore fluid composition on the mechanical and hydraulic properties. Volume changes (contraction/ expansion) have been measured on clay specimens upon exposure to salt solutions or permeation with organic liquids. Moreover, it was shown that permeation of clay with brine induces an increase of the shear strength. In addition, several models have been proposed to describe the chemo-mechanical behaviour of saturated clays under saturated conditions. A new chemo-hydro-mechanical model for unsaturated clays is under development. The chemo-mechanical effects are described within an elasto-plastic framework using the concept that chemical effects act on the plastic properties by increasing or decreasing the pre-consolidation stress. The model is based on the distinction within the material of a microstructural and a macro-structural levels. Chemical loading has a significant effect on the microstructure. The negative pressure associated with the capillary water plays its role in the interconnected macro pores. By adopting simple assumptions concerning the coupling between the two levels it is intended to reproduce the features of the behaviour of unsaturated clays when there is a change in pore fluid composition (increase or decrease of concentration). A yield surface which defines the set of yield pre-consolidation stress values, for each associated capillary suction and concentration of pore fluid should be defined. In addition, the behaviour of clays under unsaturated condition and the behaviour at full saturation under chemical loading represent two limiting cases of the framework. Studies on the compatibility of Boom Clay with large amounts of nitrate- bearing bituminized radioactive waste have recently raised a particular interest on the

  17. Insightful understanding of the role of clay topology on the stability of biomimetic hybrid chitosan-clay thin films and CO2-dried porous aerogel microspheres

    OpenAIRE

    Frindy, Sana; Primo Arnau, Ana Maria; Qaiss, Abou el Kacem; Bouhfid, Rachid; Lahcini, Mohamed; García Gómez, Hermenegildo; Bousmina, Mosto; El Kadib, Abdelkrim

    2016-01-01

    [EN] Three natural clay-based microstructures, namely layered montmorillonite (MMT), nanotubular halloysite (HNT) and micro-fibrillar sepiolite (SP) were used for the synthesis of hybrid chitosan-clay thin films and porous aerogel microspheres. At a first glance, a decrease in the viscosity of the three gel forming solutions was noticed as a result of breaking the mutual polymeric chains interaction by the clay microstructure. Upon casting, chitosan-clay films displayed enhanced hydrophilicit...

  18. Study of the effect of T-80 on the parameters of clay muds used in West Kazakhstan

    Energy Technology Data Exchange (ETDEWEB)

    Akhmetshin, E A; Utebayev, B K; Yamaliyev, V U

    1982-01-01

    Results are presented of studying the effect of oxal T-80 on the standard parameters of salt-saturated muds. The optimal concentration of T-80 was revealed in treating the muds. The findings indicate that additive of oxal T-80 reduces water output by 6-15 cm/sup 3/ in 30 min. Viscosity is insignificantly reduced. The higher the mineralization, the greater the decrease in water output. For conditions of West Kazakhstan, addition of 10-20% T-80 makes it possible to cut in half the consumption of starch in treating salt-saturated clay muds.

  19. Incorporation of treated straw and wood fly ash into clay building brick

    DEFF Research Database (Denmark)

    Chen, Wan; Ottosen, Lisbeth M.; Jensen, Pernille Erland

    2016-01-01

    High Cd content in straw and wood fly ash, generated from biomass-fired power plants, prohibits its recycling as fertilizer spreading on the landfilled. To improve and alter the current mainstream of fly ash treatment by landfilling, different approaches were tried for treatment of straw and wood...... fly ash, such as washing with water to quickly recover the highly soluble salts (mainly K and Cl), and treatment of the washed fly ash with elevated heavy metal content resulted from washing by electrodialytic remediation (EDR). The finding that SiO2 (quartz) accounted for a significant portion...

  20. Constitutive relationships for elastic deformation of clay rock: Data Analysis

    International Nuclear Information System (INIS)

    Liu, H.H.; Rutqvist, J.; Birkholzer, J.T.

    2011-01-01

    Geological repositories have been considered a feasible option worldwide for storing high-level nuclear waste. Clay rock is one of the rock types under consideration for such purposes, because of its favorable features to prevent radionuclide transport from the repository. Coupled hydromechanical processes have an important impact on the performance of a clay repository, and establishing constitutive relationships for modeling such processes are essential. In this study, we propose several constitutive relationships for elastic deformation in indurated clay rocks based on three recently developed concepts. First, when applying Hooke's law in clay rocks, true strain (rock volume change divided by the current rock volume), rather than engineering strain (rock volume change divided by unstressed rock volume), should be used, except when the degree of deformation is very small. In the latter case, the two strains will be practically identical. Second, because of its inherent heterogeneity, clay rock can be divided into two parts, a hard part and a soft part, with the hard part subject to a relatively small degree of deformation compared with the soft part. Third, for swelling rock like clay, effective stress needs to be generalized to include an additional term resulting from the swelling process. To evaluate our theoretical development, we analyze uniaxial test data for core samples of Opalinus clay and laboratory measurements of single fractures within macro-cracked Callovo-Oxfordian argillite samples subject to both confinement and water reduced swelling. The results from this evaluation indicate that our constitutive relationships can adequately represent the data and explain the related observations.