Papers by Keyword: WDXRF

Abstract: In this study Fe₂O₃/SBA-15 catalyst was synthesized via direct synthesis method under acidic conditions using triblock copolymer Pluronic P123 as template, tetraethyl orthosilicate as a silica source and Fe (NO₃)₃∙9H₂O as iron source. Template was removed using extraction and calcination. The obtained catalyst was characterized using XRD analysis, WDXRF spectroscopy, N₂ adsorption-desorption analysis and STEM–EDX measurements. Results of catalyst characterization showed that the synthesized Fe₂O₃/SBA-15 is mesoporous silica with 2D p6mm hexagonal mesostructure loaded with 15.6 wt.% Fe₂O₃. Average pore size was 6.95 nm, homogeneous immobilized Fe₂O₃ nanoparticles do not disrupt the porous hexagonal structure of the support.

Abstract: Among others, biomedical research is conducted for the systematic collection and analysis of data from which general conclusions can be drawn and which can increase the life quality of the patients. Given these issues, the aim of the research presented in this paper is to analyze the concentration of heavy elements from the human body, using complementary analysis methods, based on the energy dispersion spectrometry (EDS) technique.

Abstract: This paper presents a new method to separate interfering spectra obtained in wavelength dispersive x-ray fluorescence spectrometry (WDXRF). This method permits improved results to be obtained, compared to conventional analytical results and enables the determination of chemical species of the same element without chemical separation. This is done by separation of the spectra due to electronic transitions of the valence electrons. The Rietveld method [11] overcomes the problem of superimposed peaks of the species present in the specimen and simultaneously enables determination of the species and does not require standard specimens and calibration curves. This signifies a marked improvement in comparison to other techniques. Specimen surface preparation to obtain spectra is a critical stage and its effects can be minimized by using Rietveld refinement, which permits the determination of intensity relationships of superimposed peaks with the aid of mathematical models. This establishes the basic conditions to obtain more accurate results in quantitative analysis. In the determination of chemical species, it is possible to separate, for example, Cr (III) and Cr (IV), with almost 100% superimposition.