bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sorption of Organic Compounds by Al and Zr-Hydroxy-Intercalated and Pillared Bentonite
Authors: Matthes Winnie , Kahr Guenther 
Published: August 2006

AbstractOwing to their large and chemically active surface, hydroxy-intercalated and pillared clays can be potent sorbents for organic compounds. The sorption behavior of Al and Zr-hydroxy-intercalated bentonite (HAl-, HZr-MX80), Al and Zr-pillared bentonite (Al-MX80, Zr-MX80), and a commercial Al-pillared bentonite (EXM 534) for 3-chloroaniline (3-CA), atrazine (AT), and 3-chlorophenol (3-CP) was investigated. The results were compared with the sorption behavior of the untreated Na-rich bentonite (MX80) and granulated activated carbon (GAC). Also the influence of the salinity of the sorbate and the age of the sorbents was studied.Al and Zr-hydroxy-intercalated and pillared bentonites sorbed higher amounts of 3-CA, AT, and 3-CP than the untreated bentonite. The quantities sorbed related to the electron-donating properties of the sorbate and the acidity of the sorbents. Sorbed quantities increased from the hydroxy-intercalated to the pillared species, and from the Al to the Zr forms. The organic bases, 3-CA and AT, were sorbed in higher quantities than the organic acid 3-CP. For AT, the sorbents exhibited a high affinity. Aging of the samples and a high ionic strength of the sorbate reduced the sorption of 3-CA, whereas the sorption of AT was not affected greatly. The sorption capacity of GAC for organic bases was generally higher than that of the hydroxy-intercalated and pillared bentonites.The data suggest that at initial concentrations at a ppm level, 3-CA and AT can be entirely removed from aqueous solutions by Al and Zr-hydroxy-intercalated and pillared bentonites. These materials, especially Zr-pillared bentonites, represent potent alternative sorbents for atrazine, chloroanilines, and probably a wide range of other organic bases.
Effects of Clay Fraction and Temperature on the H2O Self-Diffusivity in Hectorite Gel: A Pulsed-Field-Gradient Spin-Echo Nuclear Magnetic Resonance Study
Authors: Nakashima Yoshito 
Published: August 2006

AbstractSelf-diffusion coefficients of H2O molecules in Na-rich hectorite gel were measured by 'H nuclear magnetic resonance (NMR), Spin-echo pulse sequences with magnetic field gradient pulses for the translational diffusion measurement were applied to the hectorite gel at the Larmor frequency of 20 MHz. Effects of clay fraction (0-51.2 wt. %) and temperature (20.0-60.3°C) were studied. The results show: (1) Phenomenologically, the self-diffusion coefficient, D, of 1H2O in the clay gel is expressed by the normalized diffusivity, D/D0 = exp(−0.0257w), where D0 is the water self-diffusivity in bulk water at temperature and w is the weight fraction of the hectorite (wt. %). (2) The activation energy of H2O diffusivity in the hectorite gel is nearly equal to that in bulk water. Hence, the normalized diffusivity, D/D0, obeys a temperature-independent curve. (3) The exponential dependence of D/D0 on w for w <30 wt. % is explained by a random-walk model, in which free or unbound H2O molecules migrate in the geometrically complex and tortuous pore structure of randomly scattered clay-mineral grains.
Reaction Mechanisms of Smectite Illitization Associated with Hydrothermal Alteration from Ponza Island, Italy
Authors: Ylagan Robert F. , Altaner Stephen P. , Pozzuoli Antonio 
Published: August 2006

AbstractA hydrothermally altered rhyolitic hyaloclastite from Ponza island, Italy, has four alteration zones with unique clay assemblages: (1) a non-pervasive argillic zone characterized by smectite; (2) a propylitic zone with interstratified illite-smectite (I-S) containing 10–85% illite (I); (3) a silicic zone composed of I-S with ≥90% I and pure illite; and (4) a sericitic zone with I-S ranging from 66% I to pure illite. Atomic force microscopy reveals abrupt changes in particle morphology with illitization, including initial changes from anhedral plates to laths and then to euhedral plates and hexagonal plates. I-S particles progressively thicken with illitization and mean particle area (basal plane) remains constant from pure smectite to I-S with 80% I. However, particle area increases from 90 to 100% illite. Computer modeling of I-S structural forms indicates octahedral cation ordering progressively changes fromcis-vacant smectite to interstratifiedcis-andtnuis-vacant I-S, and then totrans-vacant illite. In addition, polytypes progressively change from 1Mdto 1M, and then to 2M, illite. Electron-microprobe and X-ray fluoresence analyses show that I-S chemistry progressively changes during illitization, evolving toward a phengitic composition with ∼0.89 fixed interlayer K+per O10(OH)2. Octahedral Mg2+shows little change with illitization, varying from 0.3 to 0.5 cations per O,10(OH)2. The layer charge of smectite is ~0.38 equivalents per O10(OH)2.On the basis of abrupt changes in morphology and progressive changes in polytype and chemistry, smectite illitization on Ponza involved a dissolution and recrystallization mechanism with multiple stages of nucléation and crystal growth. In this multi-step model, temperature of alteration provided the major control for the layer composition, polytype, and morphology of I-S crystallites. Other factors that may play a secondary role include: K+availability, water-rock ratio, and permeability. Alternatively, the mechanism of I-S and illite formation at Ponza and other hydrothermal environments may occur by direct precipitation of I-S crystallites from rhyolite glass and may not involve progressive reactions of smectite precursors.
Characterization of Silanol Groups in Protonated Magadiite by 1H and 2H Solid-State Nuclear Magnetic Resonance
Authors: Komori Yoshihiko , Miyoshi Masaki , Hayashi Shigenobu , Sugahara Yoshiyuki , Kuroda Kazuyuki 
Published: August 2006

AbstractSilanol groups in protonated magadiite (H-magadiite) were characterized by 1H and 2H solid-state nuclear magnetic resonance (NMR). H-magadiite and deuterated (D) magadiite were synthesized by the treatment of Na-rich magadiite with 0.2 N HC1 and 0.2 N DC1, respectively. In the 1H NMR spectrum measured at room temperature, silanol groups of H-magadiite showed two signals at 3.75 and 5.70 ppm, indicating that two types of silanol groups were present. The ratio of silanol groups associated with strong hydrogen bonding (5.70 ppm) to those with weaker hydrogen bonding (3.75 ppm) was 2 to 1. The 2H NMR spectra of deuterated magadiite were measured in the temperature range from 150 to 440 K. In the spectra measured at temperatures below 294 K, silanol groups showed Pake doublet patterns. These patterns were composed of two components corresponding to the two types of silanol groups shown in the 1H NMR analysis. Both silanol groups produced wobbling motions with increasing temperature. Above 294 K, the profile of the Pake doublet pattern was transformed gradually to a near triangular pattern, indicating that the silanol groups underwent other motions also, such as a two-site jump.
Self-Organized Inorganic-Organic Hybrids Induced by Silylating Agents with Phyllosilicate-Like Structure and the Influence of the Adsorption of Cations
Authors: Da Fonseca Maria G. , Barone José S. , Airoldi Claudio 
Published: August 2006

AbstractTwo analogous inorganic-organic hybrids with a phyllosilicate-like structure SILMg1 and SILMg2, containing 3-aminopropyl- and N-propylethylenediaminetrimethoxysilane were synthesized through a sol-gel process. These hybrids adsorbed divalent cations of cobalt, nickel, copper, and zinc from aqueous solution to give the effectiveness of adsorption capacities in the sequence Cu2+ > Zn2+ > Ni2+ > Co2+. SILMg1 has a higher capacity of adsorption than SILMg2. Elemental analysis, X-ray diffractometry, thermal analysis, infrared and nuclear magnetic resonance spectroscopies, and energy dispersive system microscopy characterized all hybrids. The proposed adsorption mechanism involves dissolution of the precursor matrix, formation of a phyllosilicate around the adsorbed ion, and a complexation of the cation by the amino-pendant groups in the interlayer. These new phyllosilicates are more crystalline than the original hybrids. The adsorption of Co2+ increases the interlayer distance to maximum values of 1.81 and 2.24 Å for SILMg1 and SILMg2, respectively. Thermal analysis data showed a decrease of thermal stability with cation adsorption. Si-O-Si groups were detected by infrared spectroscopy in all hybrids and a band at 1384 cm-1 was assigned to the nitrate counter anion, which indicates the participation of this ion in the sphere of coordination of the interlayer complexes. The photomicrographs obtained by scanning electron microscopy showed the organized distribution of the sheet structure for these synthesized phyllosilicates.
Chromate Removal by Dithionite-Reduced Clays: Evidence from Direct X-Ray Adsorption Near Edge Spectroscopy (XANES) of Chromate Reduction at Clay Surfaces
Authors: Taylor Robert W. , Shen Siyuan , Bleam William F. , Tu Shu-I 
Published: August 2006

AbstractChromium(VI) in the environment is of particular concern because it is toxic to both plants and animals, even at low concentrations. As a redox-sensitive element, the fate and toxicity of chromium is controlled by soil reduction-oxidation (redox) reactions. In-situ remediation of chromium combines reduction of Cr(VI) to Cr(III) and immobilization of chromium on mineral surfaces. In this study, Fe-rich smectite, montmorillonite, illite, vermiculite, and kaolinite were examined to determine reactivity in sorption-reduction of Cr(VI). The clays were compared to forms that were reduced by sodium dithionite. Clays containing Fe(II) efficiently removed soluble Cr(VI) from solution. Chromium K-edge X-ray absorption near edge structure (XANES) suggested that clays containing Fe(II) reduced Cr(VI) to Cr(III), immobilizing Cr at the clay/water interface. Adsorption of Cr(VI) by the Fe(II)-containing clay was a prerequisite for the coupled sorption-reduction reaction. Sodium dithionite added directly to aqueous suspensions of non-reduced clays reduced Cr(VI) to Cr(III), but did not immobilize Cr on clay surfaces. The capacity of clays to reduce Cr(VI) is correlated with the ferrous iron content of the clays. For dithionite-reduced smectite, the exchangeable cation influenced the sorption reaction, and thus it also influenced the coupled sorption-reduction reaction of Cr(VI). The pH of the aqueous system affected both the amount of Cr(VI) reduced to Cr(III) and the partition of Cr(III) between aqueous and adsorbed species. A plot of pH vs. amount (adsorption envelope) adsorbed for the coupled sorption-reduction reaction of Cr by reduced smectite exhibited a similar pattern to that of typical anion-sorption.
Pedogenic Smectites in Podzols from Central Finland: An Analytical Electron Microscopy Study
Authors: Gillot Florence , Righi Dominique , Elsass Françoise 
Published: August 2006

AbstractTransmission electron microscopy (TEM) including high-resolution transmission electron microscopy (HRTEM) and analytical electron microscopy (AEM) were used to study the fine clay fraction (<0.1 μm) from the eluvial E horizon of podzols located in central Finland that had developed from till materials. Soils of increasing age (6500-9850 y BP) were selected to represent a chronosequence of soil development. Expandable phyllosilicates (vermiculite, smectites) are formed in the eluvial E horizon of podzols in a short time (6500 y). TEM observations show that dissolution and physical-breakdown processes affect the clay particles. As the age of the soils increases, fragmentation and exfoliation of large precursor minerals lead to thinner clay particles of two to three layers thick. The chemical compositions of individual particles obtained by AEM indicate that expandable phyllosilicates from the E horizon of podzols are heterogeneous, involving a mixture of vermiculite, Mg-bearing smectites, and aluminous beidellite. Results suggest that heterogeneity is related to the nature of their precursors. Vermiculite and Mg-bearing smectites are derived from biotite and chlorite weathering whereas phengitic micas alter to aluminous beidellite. Because the transformation of biotite and chlorite is more rapid than phengitic micas, biotite and chlorite contributes predominantly to smectites in the younger soils, as long as ferromagnesian phyllosilicates are present in the E horizons. If not, a larger proportion of smectites is derived from phengitic micas in the older soils. Direct measurement of d(001 ) values on lattice fringe images from alkylammonium-saturated samples shows that interlayer charge varies from high-charge expandable minerals (0.6–0.75 per half unit cell) in the younger soils to 0.5–0.6 per half unit cell in the oldest soils. Thus, the proportion of the components in the clay assemblage, as well as their chemistry and interlayer charge, change over time with soil evolution.
Use of X-Ray Transmission Diffractometry for the Study of Clay-Particle Orientation at Different Water Contents
Authors: Iñigo A. C. , Tessier D. , Pernes M. 
Published: August 2006

AbstractHomoionic Ca-saturated clay pastes were prepared and drying curves were obtained by applying suction pressures from 1 kPa to 100 MPa, A transmission device was used to study particle orientation by placing the clay in a cell specially designed to obtain diagrams corresponding to different sample orientations. The 00l and hk0 reflections were compared to determine the best reflections for studying clay-particle orientation. Depending on the clay, 00/ reflections or the 020 reflection and/or hkl bands can be used to analyze orientation. In many cases the 020 reflection is preferred because the intensity of the peak is high and appears to be independent of the H2O content and the degree of stacking order of layers along the [001] direction.For interstratified clays, the conditions required to obtain 00l reflections depended on several factors, the most important of which is the water content. Also, the intensity relating to particie orientation depends on (1) particle extension (size) in the (001) plane and (2) the crystal structure. Illite crystals of <1000 A gave a poorly oriented clay matrix. In contrast, large aggregates of illite, smectite, and kaolinite particles (>10,000 Å) showed a strongly oriented system. The particles of smectites may be curved and the dry material was poorly oriented owing to weak cohesion forces between the layers in comparison to illite.The study of the orientation of particles by X-ray diffraction on hydrated samples may be affected by sample mounting techniques. Any change in the content or the way the sample is mounted may modify the microstructure of a material.Clay containing a high water content affects the disorientation of particles, whereas, for the dry samples, pore size, pore volume, and solid continuity are associated with the geometry and crystal structure of the clay matrix.
Detrital Origin of a Sedimentary Fill, Lechuguilla Cave, Guadalupe Mountains, New Mexico
Authors: Foos Annabelle M. , Sasowsky Ira D. , LaRock Edward J. , Kambesis Patricia N. 
Published: August 2006

AbstractLechuguilla Cave is a hypogene cave formed by oxidation of ascending hydrogen sulfide from the Delaware Basin. A unique sediment deposit with characteristics suggesting derivation from the land surface, some 285 m above, was investigated. At this location, the observed stratigraphy (oldest to youngest) was: bedrock floor (limestone), cave clouds (secondary calcite), calcite-cemented silstone, finely laminated clay, and calcite rafts. Grain-size analysis indicates that the laminated clay deposits are composed of 59-82% clay-size minerals. The major minerals of the clay were determined by X-ray diffraction analysis and consist of interstratified illite-smectite, kaolinite, illite, goethite, and quartz. Scanning electron microscopy observations show that most of the clay deposit is composed of densely packed irregularshaped clay-size flakes. One sample from the top of the deposit was detrital, containing well-rounded, silt-size particles.Surface soils are probably the source of the clay minerals. The small amount of sand- and silt-size particles suggests that detrital particles were transported in suspension. The lack of endellite and alunite is evidence that the clays were emplaced after the sulfuric-acid dissolution stage of cave formation. Fossil evidence also suggests a previously existing link to the surface.
Surface Enthalpy of Boehmite
Authors: Majzlan Juraj , Navrotsky Alexandra , Casey William H. 
Published: August 2006

AbstractThe persistence of many seemingly metastable mineral assemblages in sediments and soils is commonly attributed to their sluggish transformation to the stable-phase assemblage. Although undoubtedly kinetics plays a major role, this study shows that thermodynamic factors, particularly surface energy, significantly influence the free energy. Enthalpies of formation of boehmite samples with variable surface area were derived using high-temperature oxide-melt calorimetry. The average surface enthalpy for all faces terminating boehmite particles was calculated at +0.52 ± 0.12 J/m2. This value represents the surface enthalpy for surfaces exposed to vacuum assuming that H2O adsorbed on the surface of boehmite is loosely bound. These results show that the enthalpy of formation of boehmite may vary by ≤8 kJ/mol as a function of particle size. An overview of published values of surface energies of gibbsite, γ-Al2O3, corundum, and the results here indicates that the hydrated phases (boehmite, gibbsite) have lower surface energies than the anhydrous phases (corundum, γ-Al2O3). Lower surface energies allow the hydrated phases to maintain high surface area, i.e., small particle size. Similar surface energies of boehmite and gibbsite suggest kinetic control favoring the crystallization of boehmite or gibbsite from aqueous solution. The enthalpy of formation of bulk boehmite from the elements was calculated at −994.0 ±1.1 kJ/mol. Combining this result with the data in existing thermodynamic databases, we confirm that bulk boehmite is metastable with respect to bulk diaspore at ambient conditions.
Editorial
Authors: Spranger Tade M 
Published: August 2006

AbstractMechanisms of alternative dispute resolution become more and more important in the legal world. The decision of the WTO Appellate Body in the so-called “hormone case” highlighted the growing relevance of DR methods in the field of health and consumer protection. The pending case of GM food labelling in the European Community is one major example for the role of ADR in biotechnology law. As biotech is a delicate area of law which makes it extremely hard to analyse, define, and interpret the relevant provisions, it is predestined for the application of ADR.
Indonesia's Regulation on the Biosafety of Genetically Engineered Products
Authors: Spranger Tade Matthias 
Published: August 2006

AbstractOn 19 May 2005, Indonesia set into force Regulation Number 21 on the Biosafety of Genetically Engineered Products (hereinafter: Biosafety Regulation), which implements not only basic requirements of the Convention on Biological Diversity (CBD) and the Biosaftey Protocol, but also several provisions of Law Number 23 of 1997 on Environmental Management. According to art. 2 (1), the purpose of this Regulation is to ensure an adequate level of environmental safety, food safety and or animal feed safety of genetically engineered products (GEP) and its use in the area of agriculture, fishery, forestry, industry, environment and nonpharmaceutical health. In addition, the regulation should improve efficiency and effectiveness of GEP use for the people's welfare based on the principles of health and biological resource management, consumer protection and certainty in operating business. The regulation includes provisions on the type and requirement of GEP, research on and development of GEP, importation of GEP from foreign countries, assessment, release, and distribution and use of GEP, control of GEP, as well as on the institutional framework and cost.
Recent Landmark Changes in Japanese Biotechnology & University Patenting (Part II)
Authors: Tessensohn John A , Yamamoto Shusaku 
Published: August 2006

AbstractBiotechnology Strategy CouncilThe finalized 2002 Biotechnology Strategy Guidelines issued by the Biotechnology Strategy Council called for “unified planning, drafting and comprehensive coordination of budgetary allocation policies and their execution, for all budgets biotechrelated science and technology budgets (amongst the Council for Science and Technology Policy, related ministries and agencies)” and to “build up and improve the funding functions of budget-allocating institutions” with competitive research funds and transparent evaluation criteria.In the past, this biotechnology funding was jealously controlled by the differing government Ministries and agencies e.g., METI, MEXT, Ministry of Labor, Health and Welfare with their respective broad portfolios, and there were concerns that “eventually the bureaucrats walk off and follow the particular interest of their ministry”, with the result that “the Japanese scientific community does not have very much influence on research funding”. It remains to be seen whether the “unified planning, drafting and comprehensive coordination” will improve the implementation of the 2002 Biotechnology Strategy Guidelines discussed earlier.
Bioprocessing: Engineering Know-How in Greater Demand than Ever
Authors: Hirche Christina , Butcher Charles 
Published: August 2006

AbstractIntroductionSeveral studies forecast that the share of biotechnological processes in the total sales volume of chemical products will probably soar to around 15–20 % by 2010. Alone for the chemical industry, the potential value added of biotechnological production has been predicted to reach € 11–22 billion worldwide annually by then. The value added stems not only from new biotechnological products, but also from the effects of improved manufacturing processes. At ACHEMA 2006 in May 2006 in Frankfurt am Main - the world's leading event for the process industries - besides the integral general topic Biotechnological Equipment, which focuses on the equipment sector a special Industrial Biotechnology Exhibition and a Partnering Conference took place, thus paying tribute to the growing significance of industrial biotechnology and supporting international networking.
Industrial Cleaning of Implants: Performance Validation of Cleaning Scheme
Authors: Frauchiger V , Weber B , Maurer T , Ruetti G , Luginbuehl R 
Published: August 2006

Abstract
The quality of medical devices depends strongly on the proper cleaning of the devices in the line of processing. Residue-free implants are not only a benefit for the patient in the long term, but they also help to reduce the number of rejections due to insufficient surface quality. The performance of the new, fully automated aqueous immersion cleaning system revealed a very high cleaning efficiency for metallic implants. An organically based model process adjuvant was used as contaminant. Custom designed metallic bodies made of implant quality material and exhibiting different surface textures served as test coupons. The analysis of the residues was carried out using gas chromatography separation and mass spectrometry analysis. The amount of organic residues found on the test coupons was below the set quantification limit of 0.1 mg—most of the time even below the detection limit of 0.01 mg total organic compounds.