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https://www.readbyqxmd.com/read/28341479/a-method-for-independent-modelling-in-support-of-regulatory-review-of-dose-assessments
#1
Björn Dverstorp, Shulan Xu
Several countries consider geological disposal facilities as the preferred option for spent nuclear fuel due to their potential to provide isolation from the surface environment on very long timescales. In 2011 the Swedish Nuclear Fuel & Waste Management Co. (SKB) submitted a license application for construction of a spent nuclear fuel repository. The disposal method involves disposing spent fuel in copper canisters with a cast iron insert at about 500 m depth in crystalline basement rock, and each canister is surrounded by a buffer of swelling bentonite clay...
March 22, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28303615/rare-earth-elements-and-select-actinoids-in-the-canadian-house-dust-study
#2
Pat E Rasmussen, Christine Levesque, Marc Chénier, H David Gardner
Nationally representative baseline data are presented for rare earth elements (REE), plus thorium (Th) and uranium (U) in house dust sampled from 1025 urban homes, in units of concentrations (μg g(-1) ), loadings (μg m(-2) ) and loading rates (ng m(-2) day(-1) ). Spearman rank correlations indicate that, in addition to outdoor sources, consumer products and building materials can influence indoor dust concentrations of REE, Th and U. Correlations (p <0.01) with numbers of occupants, dogs and cats suggest soil track-in...
March 17, 2017: Indoor Air
https://www.readbyqxmd.com/read/28303542/sorption-and-desorption-of-silver-ions-by-bentonite-clays
#3
Leonel Vinicius Constantino, Juliana Nunes Quirino, Alessandra Maffei Monteiro, Taufik Abrão, Paulo Sérgio Parreira, Alexandre Urbano, Maria Josefa Santos
Anthropogenic activities have increased the concentration of metal species in the environment. The toxicity of silver ions to aquatic and terrestrial organisms has required monitoring by analytical methods, besides actions to promote its control as pollutant. Sorption and desorption processes are directly related to the mobility and availability of metal ions in the environment. In this context, clay minerals can be used for pre-concentration, removal and recovery of silver ions from aqueous solution. Herein, two bentonite clays (BaVC-1 and SWy-2) were characterised and applied to investigate the sorption and desorption of silver ions...
March 17, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28272993/release-behavior-and-bioefficacy-of-imazethapyr-formulations-based-on-biopolymeric-hydrogels
#4
Vikas Kumar, Anupama Singh, T K Das, Dhruba Jyoti Sarkar, Shashi Bala Singh, Rashmi Dhaka, Anil Kumar
Controlled release formulations of imazethapyr herbicide have been developed employing guar gum-g-cl-polyacrylate/bentonite clay hydrogel composite (GG-HG) and guar gum-g-cl-PNIPAm nano hydrogel (GG-NHG) as carriers, to assess the suitability of biopolymeric hydrogels as controlled herbicide release devices. The kinetics of imazethapyr release from the developed formulations was studied in water and it revealed that the developed formulations of imazethapyr behaved as slow release formulations as compared to commercial formulation...
March 8, 2017: Journal of Environmental Science and Health. Part. B, Pesticides, Food Contaminants, and Agricultural Wastes
https://www.readbyqxmd.com/read/28272039/study-of-the-effect-of-an-acid-treatment-of-a-natural-moroccan-bentonite-on-its-physicochemical-and-adsorption-properties
#5
Ikram Daou, Omar Zegaoui, Ali Amachrouq
In this study, a natural bentonite taken from a deposit in the Northeast of Morocco has been purified (PB) and treated with various HCl molarities (xHPB) in order to obtain an HCl/Bentonite weight ratio equal to 0.2, 0.4 and 0.6. The obtained physicochemical characterization results indicated that the PB sample is composed mainly of the montmorillonite phase. The impact of acid treatment was investigated by identifying changes in the chemical composition, cation exchange capacity, infrared absorption bands, crystalline structure, morphology of the particles and specific surface area...
March 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/28108163/reducement-of-cadmium-adsorption-on-clay-minerals-by-the-presence-of-dissolved-organic-matter-from-animal-manure
#6
Wenjun Zhou, Lingwei Ren, Lizhong Zhu
Clay minerals are the most popular adsorbents/amendments for immobilizing heavy metals in contaminated soils, but the dissolved organic matter (DOM) in soil environment would potentially affect the adsorption/immobilization capacity of clay minerals for heavy metals. In this study, the effects of DOM derived from chicken manure (CM) on the adsorption of cadmium (Cd(2+)) on two clay minerals, bentonite and zeolite, were investigated. The equilibrium data for Cd(2+) sorption in the absence or presence of CM-DOM could be well-fitted to the Langmuir equation (R(2) > 0...
April 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28094577/protective-role-of-bentonite-against-aflatoxin-b1-and-ochratoxin-a-induced-immunotoxicity-in-broilers
#7
Sheraz Ahmed Bhatti, Muhammad Zargham Khan, Muhammad Kashif Saleemi, Muhammad Saqib, Ahrar Khan, Zahoor Ul-Hassan
The present study was designed to investigate any ameliorative effects of bentonite (BN) against immuno-pathological alterations induced by dietary aflatoxin B1 (AFB1) or ochratoxin A (OTA) in broiler chicks. In one experiment, AFB1 (0.1, 0.2 or 0.6 mg/kg feed) was fed alone and par alley with bentonite clay (3.7 or 7.5 g/kg feed) to the broilers. In the second experiment, the broilers were given feed contaminated with OTA (0.15, 0.3 or 1.0 mg/kg feed) alone and in combination with bentonite clay (3...
December 2017: Journal of Immunotoxicology
https://www.readbyqxmd.com/read/28069315/long-term-non-isothermal-reactive-transport-model-of-compacted-bentonite-concrete-and-corrosion-products-in-a-hlw-repository-in-clay
#8
Alba Mon, Javier Samper, Luis Montenegro, Acacia Naves, Jesús Fernández
Radioactive waste disposal in deep geological repositories envisages engineered barriers such as carbon-steel canisters, compacted bentonite and concrete liners. The stability and performance of the bentonite barrier could be affected by the corrosion products at the canister-bentonite interface and the hyper-alkaline conditions caused by the degradation of concrete at the bentonite-concrete interface. Additionally, the host clay formation could also be affected by the hyper-alkaline plume at the concrete-clay interface...
December 24, 2016: Journal of Contaminant Hydrology
https://www.readbyqxmd.com/read/27934265/cosolvent-effects-on-dechlorination-of-soil-sorbed-polychlorinated-biphenyls-using-bentonite-clay-templated-nanoscale-zero-valent-iron
#9
Kai Yu, G Daniel Sheng, Wesley McCall
Zero-valent iron synthesized using bentonite clay as a template (CZVI) was tested for its reactivity toward polychlorinated biphenyl (PCB) dechlorination in soil slurries. Aqueous-phase decachlorobiphenyl (PCB209) was rapidly dechlorinated by CZVI with a reaction rate 10 times greater than that by conventional nanoscale zerovalent iron. This superior reactivity was due largely to the nanoscale size (∼0.5 nm) of the ZVI particles located in the clay galleries. In soil slurries where PCB209 was strongly soil-bound, adding ethanol as an organic cosolvent led to increased PCB209 desorption into the liquid phase, thereby enhancing the PCB209 dechlorination with CZVI...
December 6, 2016: Environmental Science & Technology
https://www.readbyqxmd.com/read/27842827/base-triggered-release-of-insecticide-from-bentonite-reinforced-citric-acid-crosslinked-carboxymethyl-cellulose-hydrogel-composites
#10
Dhruba Jyoti Sarkar, Anupama Singh
Biopolymeric clay hydrogels composites, synthesized from crosslinking of carboxymethyl cellulose with citric acid in the presence of bentonite, were used to develop base triggered release formulations (TRFs) of thiamethoxam (3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro)amine) through an ex-situ encapsulation technique. Hydrogels, hydrogel-bentonite composites and their formulations were characterized by (1)H NMR, IR spectroscopy, XRD, and SEM-EDS. Triggered release of thiamethoxam from the developed formulations was studied in water (pH 7-11) with the help of HPLC and subjected to kinetics analysis using different models...
January 20, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/27837119/the-efficacy-of-raw-and-concentrated-bentonite-clay-in-reducing-the-toxic-effects-of-aflatoxin-in-broiler-chicks
#11
T A Shannon, D R Ledoux, G E Rottinghaus, D P Shaw, A Daković, M Marković
The objective of this study was to evaluate the efficacy of two adsorbents, a raw bentonite clay (RC) and a concentrated bentonite clay (CC), in ameliorating the toxic effects of aflatoxin B1 (AFB1). Results of the in vitro study (pH 3.0) indicated the CC adsorbed more AFB1 than RC (93.39 mg/g vs. 79.30 mg/g) suggesting that CC may be more effective than RC in reducing the toxic effects of AFB1 One hundred and eighty day-old straight run broiler chicks were assigned to 6 replicate pens of 5 chicks each and assigned to 6 dietary treatments from hatch to day 21...
November 11, 2016: Poultry Science
https://www.readbyqxmd.com/read/27826951/natural-minerals-coated-by-biopolymer-chitosan-synthesis-physicochemical-and-adsorption-properties
#12
T M Budnyak, E S Yanovska, O Yu Kichkiruk, D Sternik, V A Tertykh
Natural minerals are widely used in treatment technologies as mineral fertilizer, food additive in animal husbandry, and cosmetics because they combine valuable ion-exchanging and adsorption properties together with unique physicochemical and medical properties. Saponite (saponite clay) of the Ukrainian Podillya refers to the class of bentonites, a subclass of layered magnesium silicate montmorillonite. Clinoptilolits are aluminosilicates with carcase structure. In our work, we have coated biopolymer chitosan on the surfaces of natural minerals of Ukrainian origin - Podilsky saponite and Sokyrnitsky clinoptilolite...
December 2016: Nanoscale Research Letters
https://www.readbyqxmd.com/read/27809675/bentonite-toxicology-and-epidemiology-a-review
#13
L Daniel Maxim, Ron Niebo, Ernest E McConnell
Bentonite, a clay with numerous industrial and consumer applications, is mined and processed in many countries of the world. Its many beneficial uses also create the potential for widespread occupational and consumer exposure. The available studies on toxicity and epidemiology indicate that the principal exposure pathway of concern is inhalation of respirable dust by occupationally exposed cohorts. Bentonite itself is probably not more toxic than any other particulate not otherwise regulated and is not classified as a carcinogen by any regulatory or advisory body, but some bentonite may contain variable amounts of respirable crystalline silica, a recognized human carcinogen...
November 2016: Inhalation Toxicology
https://www.readbyqxmd.com/read/27743792/fate-of-nano-and-microplastic-in-freshwater-systems-a-modeling-study
#14
Ellen Besseling, Joris T K Quik, Muzhi Sun, Albert A Koelmans
Riverine transport to the marine environment is an important pathway for microplastic. However, information on fate and transport of nano- and microplastic in freshwater systems is lacking. Here we present scenario studies on the fate and transport of nano-to millimetre sized spherical particles like microbeads (100 nm-10 mm) with a state of the art spatiotemporally resolved hydrological model. The model accounts for advective transport, homo- and heteroaggregation, sedimentation-resuspension, polymer degradation, presence of biofilm and burial...
January 2017: Environmental Pollution
https://www.readbyqxmd.com/read/27741456/long-term-diffusion-of-u-vi-in-bentonite-dependence-on-density
#15
Claudia Joseph, Jens Mibus, Paul Trepte, Christa Müller, Vinzenz Brendler, Dan M Park, Yongqin Jiao, Annie B Kersting, Mavrik Zavarin
As a contribution to the safety assessment of nuclear waste repositories, U(VI) diffusion through the potential buffer material MX-80 bentonite was investigated at three clay dry densities over six years. Synthetic MX-80 model pore water was used as background electrolyte. Speciation calculations showed that Ca2UO2(CO3)3(aq) was the main U(VI) species. The in- and out-diffusion of U(VI) was investigated separately. U(VI) diffused about 3mm, 1.5mm, and 1mm into the clay plug at ρ=1.3, 1.6, and 1.9g/cm(3), respectively...
January 1, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/27737795/mycotoxin-detoxifiers-attenuate-deoxynivalenol-induced-pro-inflammatory-barrier-insult-in-porcine-enterocytes-as-an-in-vitro-evaluation-model-of-feed-mycotoxin-reduction
#16
Seong-Hwan Park, Juil Kim, Dongwook Kim, Yuseok Moon
Deoxynivalenol (DON), the most prevalent mycotoxin worldwide, leads to economic losses for animal food production. Swine is a most sensitive domestic animal to DON due to rapid absorption and low detoxification by gut microbiota. Specifically, DON can severely damage pig intestinal tissue by disrupting the intestinal barrier and inducing inflammatory responses. We evaluated the effects of several mycotoxin detoxifiers including bentonites, yeast cell wall components, and mixture-typed detoxifier composed of mineral, microorganisms, and phytogenic substances on DON-insulted intestinal barrier and pro-inflammatory responses using in vitro porcine enterocyte culture model...
February 2017: Toxicology in Vitro: An International Journal Published in Association with BIBRA
https://www.readbyqxmd.com/read/27699284/beyond-waste-new-sustainable-fillers-from-fly-ashes-stabilization-obtained-by-low-cost-raw-materials
#17
N Rodella, M Pasquali, A Zacco, F Bilo, L Borgese, N Bontempi, G Tomasoni, L E Depero, E Bontempi
A sustainable economy can be achieved only by assessing processes finalized to optimize the use of resources. Waste can be a relevant source of energy thanks to energy-from-waste processes. Concerns regarding the toxic fly ashes can be solved by transforming them into resource as recycled materials. The commitment to recycle is driven by the need to conserve natural resources, reduce imports of raw materials, save landfill space and reduce pollution. A new method to stabilize fly ash from Municipal Solid Waste Incinerator (MSWI) at room temperature has been developed thanks to COSMOS-RICE LIFE+ project (www...
September 2016: Heliyon
https://www.readbyqxmd.com/read/27639464/competitive-adsorption-of-toxic-metals-on-bentonite-and-use-of-chitosan-as-flocculent-coagulant-to-speed-up-the-settling-of-generated-clay-suspensions
#18
M Ferhat, S Kadouche, N Drouiche, K Messaoudi, B Messaoudi, H Lounici
Evaluation of modified Algerian clay as mineral adsorbent was done for its adsorbing capacity on copper (Cu) and Zinc (Zn) cations. The results obtained show a rapid kinetic adsorption for both metals (less than 2 h) following the pseudo-second order model with high elimination rates of 67.2 and 61.8% for Cu and Zn respectively. The adsorption isotherms analyzed with Langmuir model revealed a correlation with the experimental values. While the use of obtained chitosan at room temperature, as flocculent coagulant, accelerates the decantation of the colloidal particles in suspension generated after adsorption process...
December 2016: Chemosphere
https://www.readbyqxmd.com/read/27573502/application-of-radiation-chemistry-to-some-selected-technological-issues-related-to-the-development-of-nuclear-energy
#19
REVIEW
Krzysztof Bobrowski, Konrad Skotnicki, Tomasz Szreder
The most important contributions of radiation chemistry to some selected technological issues related to water-cooled reactors, reprocessing of spent nuclear fuel and high-level radioactive wastes, and fuel evolution during final radioactive waste disposal are highlighted. Chemical reactions occurring at the operating temperatures and pressures of reactors and involving primary transients and stable products from water radiolysis are presented and discussed in terms of the kinetic parameters and radiation chemical yields...
October 2016: Topics in Current Chemistry (Journal)
https://www.readbyqxmd.com/read/27533861/destabilization-dynamics-of-clay-and-acid-free-polymers-of-ferric-and-magnesium-salts-in-amd-without-ph-adjustment
#20
I O Ntwampe, F B Waanders, J R Bunt
The physicochemical treatment was employed to treat acid mine drainage (AMD) in the removal of turbid materials using clay only (exp A) and a combination of clay, FeCl3 and Mg(OH)2 (exp B) to form a polymer. A 5 g sample of clay (bentonite) was added to 1.2 L of AMD and treated in a jar test at 250 rpm for 2 min and reduced to 100 rpm for 10 min. A 200 mL sub-sample from the 1.2 L mother liquor was poured into five 500 mL glass beakers, and 20 mL dosages of a polymer of 0.1 M Fe(3+) in (FeCl3) and 0.1 M Mg(2+) in (Mg(OH)2) was added to the beakers...
2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
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