Utiliza����o de turfa para remo����o de metais potencialmente t��xicos de uma empresa recicladora de pl��sticos

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Phonon confinement model to measure the average sizes of anatase nanoparticles synthesized by a solvothermal method using H2O2

In this work, crystalline titanium dioxide (TiO2) nanoparticles with variable average crystallite sizes (e.g., 8 nm) and surface areas (e.g., 192 m�� g-1) were synthesized in pure anatase phase using H2O2 to reduce the hydrolysis rate of the titanium ions. An isopropanol (IP) solution was employed as the reaction medium. The TiO2 nanoparticles were characterized by powder X-ray diffraction analysis (XRD), Raman spectroscopy and transmission electron microscopy (TEM). By changing the synthesis parameters it was possible to control nanoparticle size and avoid the coalescence process. A dependence of the Raman wavenumber on the nanocrystal sizes was determined, which is quite useful for a quick check of the size of TiO2 nanocrystals.

Estudo do efeito de c��rio como sensibilizador e ativador, em matrizes de difenilfosfinatos de lant��nio, dopadas com eur��pio e/ou t��rbio

This paper aims the preparation, characterization and study of luminescence, particularly as for the cerium ion action as activator or sensitizer, in diphenylphosphinate of lanthanum compounds trivalent ions cerium-, europium-, and/or terbium-doped. The following compounds were prepared and studied: i) La1-(x+y)CexEuy(DFF)3; ii) La1-(x+y)CexTby(DFF)3; iii) La1-(x+y+z)CexEuyTbz(DFF)3, with x = 10%, y = 5% e z = 5%. The diphenylphosphinate of lanthanum, Ln[(Ph2)PO2]3, are complexes obtained by the mixture of lanthanides chlorides with diphenylphosphinic acid, ethanol medium. These compounds make white powders, crystalline, insoluble in normal temperature and pressure, and are chemically and thermally stable. When doping with Ce3+, Eu3+ and/or Tb3+, the compounds present characteristic luminescence. Luminescent materials are made of a host matrix incorporated with few amounts of ions called activators, which are able to present luminescence after being excited by UV light or high energy radiation, and sensitizer ions, which have the role of absorbing excitation energy and transfer it to the activator, for it to emit luminescence radiation. The infrared vibrational spectroscopy indicates that the coordination occurs by the oxygens of phosphorile group with ����PO of about 40 cm-1 compared to the free ligand. The X Ray difractograms of compounds Eu- and/or Tb-doped are similar, but they present profile of diffraction different observed by Stucchi and col. In previous papers, indicated an influence of Ce in the crystalline phase formation of these matrices. In luminescence spectrums, the excitation that can be made by the levels of ligand in 273 nm, or cerium ion in area between 300 and 400 nm were observed. In the emission spectrum, with excitation in 273 nm, is possible to observe the emission of Ce3+ below 400 nm and the Eu3+ in 592, 611 and 617 nm, and the...as a sensitizer to.

Compostos de pal��dio(II) contendo ligantes sulfurados: s��ntese, caracteriza����o e investiga����o da atividade biol��gica

This work deals with the synthesis, spectroscopic characterization of mono and polynuclear Pd(II) compounds obtained from the reaction between [PdCl2(MeCN)2] precursor and imidazolidine-2-thione (L1) and benzimidazoline-2-thione (L2). The interaction between [PdCl2(MeCN)2] and imidazolidine-2-thione, in the 1:2 molar ratio, using MeOH as solvent, yielded compound [Pd2Cl4(L1)4]Cl2 (1) whereas the complex [Pd2Br4(L1)4]Br2 (2) was obtained from the reaction between 1 and Br- ions. Binuclear compounds of general formulae [Pd2(L2)4]X2���3/2 MeOH {X= Cl-(3), Br-(4)} were synthesized using benzimidazoline-2-thione as ligand, employing the same procedure used in the synthesis of 1 and 2, respectively. The new complexes 1-4 are crystalline, air stable and soluble in methanol and dmso. The compounds were characterized by elemental analysis, IR spectroscopy, ESI/MS mass spectrometry and thermogravimetry. Coordination of the ligands L1 and L2 via sulphur atom was evidenced by the shift of the ���CS band (~499 cm-1, 1 and 2; ~620 cm-1, 3 and 4) to lower frequencies in comparison with those found in the free ligands (510 cm-1, L1; 660 cm-1, L2), indicating the weakening of the CS bom after coordination. ESI/EM mass spectra (positive mode) of the complexes 1-4 allowed atribute the molecular formulae [Pd2X4(L1)4]X2 {X= Cl-(1), Br-(2)} and [Pd2(L2)4]X2 {X= Cl-(3), Br-(4)} by the appearance of the peaks at m/z 794,61 [(1) + MeOH]+, m/z 836,77 [(2) - 2H - L1]+, m/z 810 [(3) - 2Cl]+, m/z 810 [(4) - 2Br]+. The TG-DTA curves showed that the complexes 1 and 2 are thermally stable up to 212 and 169�� C, respectively, and further decompose to metallic palladium at 527�� C (1, obt. 28,46 %; calcd. 27,88%) and 895�� C (2, obt. 22,85 %; calcd. 22,62%). Compounds 3 and 4 exhibited an initial mass loss of ~5% between 25 -146�� C related to the release of metanol molecules. The complexes 3...Fujimura Leite.

Fonte alternativa de K obtida da produ����o de KCl a partir da rocha silic��tica pot��ssica (verdete) na cultura de milho

Para produzir o termopot��ssio e, at�� mesmo, o KCl, a rocha silic��tica pot��ssica (verdete) passa pelo processo de calcina����o. Neste processo �� gerado um res��duo denominado coproduto que cont��m em sua composi����o qu��mica 3% a 4% de K2O, Ca, Mg e Si e apresenta baixa solubilidade em ��gua. O presente trabalho objetivou testar a hip��tese de que doses de K2O na forma de coproduto fornecem pot��ssio para as plantas de milho em menor quantidade do que as mesmas doses na forma de KCl, inclusive no estudo do efeito residual, e que o pot��ssio extra��do do solo pela resina trocadora de ��ons tem maior correla����o com as quantidades de pot��ssio absorvida pela planta de milho do que com o pot��ssio extra��do pela solu����o extratora de Mehlich-1. O experimento foi conduzido em casa de vegeta����o, onde foram realizados dois cultivos consecutivos de milho em amostras de Neossolo Quartizar��nico ��rtico. O delineamento foi em blocos casualizados com duas fontes de K (KCl e coproduto), tr��s doses de K2O (0, 200 e 400 kg ha-1) e quatro repeti����es, totalizando 24 unidades experimentais. Foram determinados os teores de pot��ssio extra��do da amostra de solo pela solu����o extratora de Mehlich-1 e resina trocadora de ��ons, a produ����o de mat��ria seca da parte a��rea das plantas de milho, os teores e o acumulo de pot��ssio nas plantas ap��s o primeiro e o segundo cultivo. Em dois cultivos consecutivos das plantas de milho, a aplica����o de 200 e 400 kg ha-1 de K2O na forma de KCl proporcionou o acumulo de pot��ssio na parte a��rea das plantas de 77 e 84% maior do que aplica����o dessas mesmas doses de K2O na forma de coproduto, respectivamente. A aplica����o de 200 e 400 kg ha-1 de K2O na forma de coproduto proporcionou aumentos no acumulo de pot��ssio da parte a��rea das plantas de milho de 66 e 75% em rela����o ao controle (sem K2O), respectivamente. A recupera����o de pot��ssio pelas plantas de milho tratadas com KCl foi de 92% e as plantas...

T��cnica h��brida de plasma para a deposi����o de filmes de alumina

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Filmes de nanocomp��sitos de pol��mero condutor, nanopart��culas de argila e nanopart��culas de ouro para aplica����o em sensores ambientais

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)