Non-ohmic electrical transport in the Peierls-Mott state of deuterated copper-DCNQI systems (original) (raw)
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Potential Environmental Applications of Pure Zeolitic Material Synthesized from Fly Ash
Journal of Environmental Engineering, 2001
A pure 4A/X (60/40) zeolite product was synthesized from silica extracts of the Meirama fly ash in northwestern Spain. A high cation-exchange capacity (4.7 meq/g) was obtained for the zeolitic material. The potential application of this coal fly ash conversion product for decontamination of high heavy metal waters was evaluated using three high heavy metal waters from acid mine drainage around the pyrite Huelva belt. The results were compared with those obtained with an equivalent pure commercial synthetic zeolite. A considerable reduction in the heavy metal content was attained (Zn from 174 to <0.1 mg/L, Cu from 36 to 0.1 mg/L, Fe from 444 to 0.8 mg/L, Mn from 74 to <0.1 mg/L, Pb from 1.5 to <0.1 mg/L, and Cd from 0.4 to <0.1 mg/L), even in high Ca and Fe waters using zeolite doses from 5 to 30 mg/L. Both precipitation and cation-exchange processes accounted for the reduction in the pollutant concentration in the treated waters. Leachable hazardous elements from coal fly ash, such as Mo, B, As, V, and Cr, were not fixed in the synthesis of pure zeolites from the silica extracts. Consequently, they did not restrict the potential applications of this material as an ion exchanger, unlike the zeolitic material obtained from fly ash by direct alkaline conversion.
Thermo-Raman spectroscopic study of the uranium mineral sabugalite
Journal of Raman Spectroscopy , 2005
The changes in the structure of sabugalite have been undertaken using thermo-Raman and infrared spectroscopy based upon the results of thermogravimetric analysis. Two Raman bands are observed at 835 and 830 cm-1 assigned to the (UO 2) 2+ stretching vibrations resulting from the non-equivalence of the uranyl bonds (UO 2) 2+. These bands give calculated U-O bond lengths of 1.773 and 1.7808 Å. A low intensity band is observed at 895 cm-1 assigned to the ν 3 antisymmetric stretching vibration of (UO 2) 2+ units. Five bands are observed in the 950 to 1050 cm-1 region in the Raman spectrum of sabugalite and are assigned to the ν 3 antisymmetric stretching vibration of (PO 4) 3-units. Changes in the Raman spectra reflect changes in the structure of sabugalite as dehydration occurs. No (PO 4) 3-symmetric stretching mode is observed. This result is attributed to the non-equivalence of the PO bonds in the PO 4 units. The PO 4 vibrations were not affected by dehydration. Thermo-Raman spectroscopy proved to be a very powerful technique for the study of the changes in the structure of sabugalite during dehydration.
The Science of the total environment, 2012
This paper examines Pb concentrations and sources in soil, grass and heather from the Rookhope catchment in the North Pennines, UK, an area of historical Pb and Zn mining and smelting. Currently, the area has extensive livestock and sports shooting industries. Risk assessment, using the source-pathway-receptor paradigm, requires the quantification of source terms and an understanding of the many factors determining the concentration of Pb in plants. A paired soil and vegetation (grass and heather) geochemical survey was undertaken. Results showed no direct correlation between soil (total or EDTA extractable Pb) and vegetation Pb concentration. However, regression modelling based on the Free-Ion Activity Model (FIAM) suggested that the underlying mechanism determining grass Pb concentration across the catchment was largely through root uptake. Spatial patterns of 206/207 Pb isotopes suggested greater aerosol deposition of Pb on high moorland and prevailing wind facing slopes. This was evident in the isotopic ratios of the heather plants.
Green nanotechnology – A newhope for.pdf
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Interpolymer complexation of water-soluble self-doped polyaniline
Synthetic Metals, 2008
Water-soluble polyaniline compounds are important for potential applications in organic electronics. The use of organic inks as an example require accurate control of the size and charge of the conducting particles, which both can be optimized with an additional complexation, charge neutralization. We report here the synthesis and characterization of internally doped highly sulfonated polyaniline with sulfur to nitrogen ratio S/N of ∼1. This electroactive polyelectrolyte, which has high water solubility in all pH regions, was complexed with oppositely charged poly-N-ethyl-4-vinylpyridinium bromide and the properties of such interpolymer complex were studied.
Antiwear Performance and Mechanism of an Oil-Miscible Ionic Liquid as a Lubricant Additive
ACS Applied Materials & Interfaces, 2012
An ionic liquid (IL) trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate has been investigated as a potential antiwear lubricant additive. Unlike most other ILs that have very low solubility in nonpolar fluids, this IL is fully miscible with various hydrocarbon oils. In addition, it is thermally stable up to 347°C, showed no corrosive attack to cast iron in an ambient environment, and has excellent wettability on solid surfaces (e.g., contact angle on cast iron <8°). Most importantly, this phosphonium-based IL has demonstrated effective antiscuffing and antiwear characteristics when blended with lubricating oils. For example, a 5 wt % addition into a synthetic base oil eliminated the scuffing failure experienced in neat oil and, as a result, reduced the friction coefficient by 60% and the wear rate by 3 orders of magnitude. A synergistic effect on wear protection was observed with the current antiwear additive when added into a fully formulated engine oil. Nanostructure examination and composition analysis revealed a triboboundary film and subsurface plastic deformation zone for the metallic surface lubricated by the IL-containing lubricants. This protective boundary film is believed to be responsible for the IL's antiscuffing and antiwear functionality.
Journal of Organometallic Chemistry, 2010
Diethyl 2-(ferrocenylmethylidene)malonate undergoes linear dimerization with formation of tetraethyl 2,3-diferrocenylbutane-1,1,4,4-tetracarboxylate when treated with EtMgBr in the presence of Ti(O i Pr) 4 . Under similar conditions, ethyl (E)-2-(ferrocenylmethylidene)benzoylacetate and ethyl (E,Z)-2-(ferrocenylmethylidene)acetoacetate afford linear dimerization products (3,4-diferrocenyladipic acid derivatives) and intramolecular cyclization products of the latter (3,4-diferrocenylcyclopentanol derivatives). No products of the Kulinkovich reaction (hydroxycyclopropanation of the ester groups) were observed. The structures of the compounds obtained were established based on data from IR, 1 H and 13 C NMR spectroscopy, mass spectrometry and X-ray diffraction analysis. The mechanistic aspects of these reactions are discussed. Electrochemical properties of the compounds 7a, 10 and 12 were investigated using cyclic voltammetry, one step potential chronoamperometry and square wave voltammetry. Two electrochemical processes (IeII), attributed to the oxidations of the ferrocenes moieties, E 00 (I), E 00 (II), DE 00 (IIeI) and comproportionation constant K com are reported.
Biosorption of heavy metals from mining influenced water onto chitin products
Mining influenced water (MIW) emanating from mine sites poses a major environmental concern due to its impact on water contamination caused by low pH and the presence of high concentrations of toxic metals. Chitorem SC-20 ® (raw crushed crab shells containing 40% (w/w) CaCO 3 , 30% protein, 20% chitin, 7% moisture, and 3% ash) and Chitorem SC-80 ® (the chitin polymer containing 88% chitin and 12% moisture) were used to evaluate heavy metals removal from MIW. It was found that SC-20 was very effective at neutralizing the strong acidity of MIW, even at loads as low as 1 g/L the equilibrium pH was neutral. At a load of 2 g/L, SC-20 showed a final pH of 7.94 with almost complete (>99.8%) removal of iron (120 mg/L), lead (1.1 mg/L) and zinc (79 mg/L), along with partial removal of cadmium (96% of 1.3 mg/L), cobalt (54% of 0.78 mg/L), copper (42% of 72 mg/L), and manganese (64% of 52 mg/L) from MIW. Metal removal was achieved primarily by neutralization and precipitation mainly due to the dissolution of the CaCO 3 from the SC-20. SC-80 was used to differentiate the effect of alkalinity and the amount of metal adsorption achievable by the chitin polymer. Lead (up to 1.24 mg/g), cadmium (up to 1.81 mg/g), and cobalt (up to 0.93 mg/g) from single-metal solutions were adsorbed onto the chitin polymer (SC-80). Metal adsorption onto the chitin polymer seemed to have a minor role as a mechanism of metal removal from MIW. Overall, this study demonstrated that crab-shell products can be an important alternative for MIW remediation.