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1.
Data Brief ; 27: 104709, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31737758

RESUMO

In this work are presented all the conditions of synthesis explored to obtain a new family of compound with formula [Ln(4-OHBBA)3(H2O)2] (Ln = La, Pr). Powder X ray diffraction was used to identify the different phases obtained in the synthetic study. FT-IR spectroscopy and TG analysis for La and Pr pure phases are also reported. Optical properties of optically active CPs materials, solid state photoluminescence properties of La, Pr, La-(5%Eu) and La-(5%Tb) compounds were explored. We report the absorption, excitation and emission spectrum of the 4'-hydroxi-4-biphenylcarboxylic acid and a comparative description of the radiative (and no-radiative) processes in solid state in Ln-(4-OHBBA) and Ln-BPDC compounds. Finally, a principal component analysis was conducted in order to take in account both signal contributions from the sensor (LCE at 384 nm and the europium emission at 610 nm) and for classifying the type of analytes used to test the sensing response of the materials.

2.
Environ Sci Technol ; 39(2): 585-92, 2005 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-15707059

RESUMO

Glyphosate is a non-selective, broad spectrum, post-emergent herbicide widely used in weed control. Aminomethylphosphonic acid (AMPA) is one of the main products of biodegradation of glyphosate in natural systems before its ultimate mineralization and also the breakdown product of more complex phosphonates such as nitrilotris-(methylenephosphonic acid). The adsorption isotherms and surface coverage of AMPA and glyphosate (N-phosphomethylglycine, PMG) in aqueous suspensions of goethite as a function of pH were measured. Electrophoretic mobility curves forthe PMG/goethite system were also determined. The ATR-FTIR interfacial spectra of the surface complexes of AMPA and PMG onto goethite were analyzed as a function of the pH and the surface coverage. The phosphonate moiety of these two ligands coordinates to the iron oxide surface with similar structures as the methylphosphonic acid despite the presence of the amino and/or carboxylate groups of their molecules. Two predominating complexes have been identified where the phosphonate group in PMG or AMPA bonds monodentately or bridges bidentately to the surface of iron oxide in an inner sphere mode, while the carboxylate and amino group are noncoordinated to the surface. The stability constants of the surface complexes (triple bond)FeO-P(O)(OH)--R, (triple bond)FeO--P(O)2--R, and ((triple bond)FeO)2--P(O)--R were calculated using the constant capacitance model.


Assuntos
Glicina/análogos & derivados , Glicina/química , Herbicidas/química , Compostos de Ferro/química , Organofosfonatos/química , Adsorção , Glicina/análise , Herbicidas/análise , Ferro/química , Isoxazóis , Minerais , Organofosfonatos/análise , Temperatura , Tetrazóis , Glifosato
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