983 resultados para household solid residue


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Solid-state compounds of general formula LnL(3)center dot nH(2)O, where Ln represents heavier lanthanides and yttrium and L is 2-chlorobenzylidenepyruvate, have been synthesized. Chemical analysis, simultaneous thermogravimetry-differential analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, elemental analysis and infrared spectroscopy have been employed to characterize and to study the thermal behaviour of these compounds in dynamic air atmosphere.On heating these compounds decompose in four (Gd, Tb, Ho to Lu, Y) or five (Eu, Dy) steps. They lose the hydration water in the first step and the thermal decomposition of the anhydrous compounds up to 1200 degrees C occurs with the formation of the respective oxide, Tb4O7 and Ln(2)O(3) (Ln=Eu, Gd, Dy to Lu and Y) as final residue. The dehydration enthalpies found for these compounds (Eu, to Lu and Y) were: 65.77, 55.63, 86.89, 121.65, 99.80, 109.59, 131.02, 119.78, 205.46 and 83.11 kJ mol(-1), respectively.

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Langmuir and Langmuir-Blodgett films of 16-membered azobenzocrown ether with naphthalene residue were prepared and characterized. The Langmuir monolayers were successfully transferred to form LB films onto solid substrates. The films deposited onto ITO electrodes were also used as electrodes in cyclic voltammetry and the results showed that the films had a distinct response to metal ions. (C) 2009 Elsevier B.V. All rights reserved.

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Solid-state compounds with a general formula of LnL3· nH2O, where Ln stands for lighter trivalent lanthanides (lanthanum to samarium), L is 2-methoxybenzylidenepyruvate and n=1.5, 2, 2, 1.5 and 2, respectively, have been synthesized. On heating these compounds are decompose in two or three steps. They lose their hydration water in the first step and the thermal decomposition of the anhydrous compounds occurs with the formation of the respective oxide, CeO2, Pr6O11 and Ln 2O3 (Ln=La, Nd, Sm) as final residue. The dehydration enthalpies found for these compounds (La to Sm) were: 222.7, 163.6, 497.7, 513.9 and 715.4 kJ mol-1, respectively. © 2005 Akadémiai Kiadó, Budapest.

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Solid compounds of general formula LnL3 for La and Ce and LnL3·nH2O for Pr, Nd and Sm where Ln stands for trivalent lanthanides, L is 2-chlorobenzylidenepyruvate and n=2, 3 and 2 respectively, have been synthesized. On heating these compounds decompose in two or five steps. They lose the hydration water in the first step and the thermal decomposition of the anhydrous compounds occurs with the formation of the respective oxide, CeO2, Pr6O11 and Ln 2O3 (Ln=La, Nd, Sm) as final residue. The dehydration enthalpies found for these compounds (Pr, Nd and Sm) were: 140.1, 148.2 and 221.3 kJ mol-1, respectively. © 2005 Akadémiai Kiadó, Budapest.

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Persistent organic pollutants (POPs), organochlorine pesticides and polychlorinated biphenyls (PCBs), listed as per the Stockholm Convention (α -HCH, β -HCH, γ -HCH, p,p′-DDT, o,p′-DDT, p,p′-DDD, p,p′-DDE, aldrin, endrin, dieldrin, PCBs 28, 52, 118, 138, 153, and 180), were analyzed in municipal solid waste (MSW) compost samples from three different Brazilian composting plants located in three São Paulo State cities: Araras, Araraquara and São Paulo (Vila Leopoldinha). Quantitative and qualitative analyses were carried out using gas chromatography electron capture detection (GC-ECD) and gas chromatography mass spectrometry (GC-MS) (Ion Trap, electron impact ionization), respectively. The samples were analyzed in triplicate and the target POPs were not detected by GC-ECD. Twelve pollutants were identified in two samples when qualitative analysis (GC-MS) was used (β -HCH, γ -HCH, p,p′-DDT, o,p′-DDT, p,p′-DDD, and p,p′-DDE, PCBs 28, 118, 138, 153 and 180). The composting process has advantages such as urban solid waste reduction and landfill life-span increase, however the MSW compost quality, which can be utilized for agricultural purposes, should be evaluated and be controlled. This kind of study is the first step in making available information to answer questions regarding MSW compost for sustainable agricultural use, such as the pollutants accumulation in soil and in groundwater, and plants uptake. Copyright © Taylor & Francis Group, LLC.

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Thermal and spectroscopic studies on solid trivalent lanthanides and yttrium(III) α-hydroxyisobutyrates, Ln(C4H7O 3)3·nH2O were investigated employing simultaneous thermogravimetry and differential thermal analysis (TG-DTA), elemental analysis, X-ray diffractometry, complexometry, experimental and theoretical infrared spectroscopy and TG-DSC coupled to FTIR. The dehydration of lanthanum to neodymium and terbium to thulium and yttrium compounds occurs in a single step while for samarium, europium and gadolinium ones it occurs in three consecutives steps. Ytterbium and lutetium compounds were obtained in the anhydrous state. The thermal decomposition of the anhydrous compounds occursin two consecutives steps, except lanthanum (five steps) and cerium (single step), with formation of the respective oxides CeO2, Pr6O 11, Tb4O7 and Ln2O3 (Ln = La, Nd to Lu and Y), as final residue. The resultsalso provided information concerning the composition, thermal behavior, crystallinity and gaseous products evolved during the thermal decomposition. The theoretical and experimental spectroscopic data suggested the possible modes of coordination of the ligand with the lanthanides.© 2013 Elsevier B.V.

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The stagnant effective thermal conductivities (K0) of sugar cane bagasse (SCB), wheat bran (WB), orange pulp and peel (OPP) and their combination (weight proportion 1:2:2 SCB/OPP/WB) were obtained using the line heat source method. These solid materials were applied to pectinase production via solid-state fermentation. The moisture content ranged from 4 to 80% (w.b.). A conduction mechanism through the porous media was observed, along with conduction through a liquid film and contact thermal resistance between the samples and the probe. K0 was low for intermediate moisture contents and approached the molecular conductivity of water for high moisture contents. © 2013 Copyright Taylor and Francis Group, LLC.

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The urban residues put in landfill of the city of Sa˜o Carlos-SP, Brazil, in 2004 represent 58.7 % of decomposed organic material. The aim of this research was to characterize samples of urban solid waste and its organic extracts targeting the use of this residue without damaging the environment. The curves were obtained in a nitrogen atmosphere, a heating rate of 20 C min-1 , the temperature of 30–600 C. In the original sample after humidity loss, an event occured concerning the water constitution in the TG curve with an endothermic peak in the DTA curve. There was a presence of inorganic residue in the ashes. The organic matter present in the USR sample disposed in the landfill is constituted by several polarity, organics compounds from the degradation of lignin, cellulose, lipids, and other materials which thermal stabilities are distinct. The hexane extract features in its constitution two fatty acids, stearic and triacontano´ic, which are nonpolar compounds originating from bacteria present in the residue. The acids groups in extract hexane also were evidenced by X-ray diffraction and FTIR.

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