Comparison of nickel speciation in workplace aerosol samples using sequential extraction analysis and X-ray absorption near-edge structure spectroscopy

Abstract

There is a pressing need to further develop speciation knowledge of Ni workplace aerosols as the Zatka sequential extraction method used until now to speciate workplace Ni exposures has limitations. Here we compare the Zatka and XANES methods and evaluate XANES spectroscopy as a more appropriate and accurate technique for identifying nickel species in workplace aerosols. XANES spectroscopy is capable of identifying unique Ni species in the unaltered samples. Our findings indicate some significant departures in speciation assignment between the Zatka and XANES methods. In particular, the Zatka method can overestimate the soluble Ni fraction and it may underestimate the sulphidic and metallic fractions in some samples. Of particular importance, XANES is able to identify component sulphidic species. This information can lead to more accurate exposure matrices and more refined epidemiological analysis of respiratory cancer causation in sulphidic Ni processing.

Influence of the Preparation Conditions of Oxidic NiMo/Al2O3 Catalysts on the Sulfidation Ability: A Quick-XAS and Raman Spectroscopic Study

“…Nevertheless the XANES spectra of catalysts are superimposable neither to the one of the Ni 3 S 2 reference nor to the spectra of NiS and NiS 2 reported in the literature. 63,64 Actually the shape of the XANES spectra of the sulfide catalysts is very similar to the one published by Hamabe et al 65 5 and Figure S11B). This Ni−S distance is well in line with the distance found by Koizumi et al…”

“…Nevertheless the XANES spectra of catalysts are superimposable neither to the one of the Ni 3 S 2 reference nor to the spectra of NiS and NiS 2 reported in the literature. 63,64 Actually the shape of the XANES spectra of the sulfide catalysts is very similar to the one published by Hamabe et al 65 for a homemade sulfide NiMo/Al 2 O 3 catalyst (Ni/Mo = 0.2), which was identified as representative of the active NiMoS phase 66 by the analysis of RT EXAFS data in an extended k-range. It is nevertheless important to note that, as for the spectrum reported by Hamabe et al, the XANES spectra reported for the calcined sulfided catalysts (calc-sulf-NiMo and dehydrated-calcsulf-NiMo) display at 8353 eV a small bump that we ascribe as a reminiscence of the white line characteristic of the NiAl 2 O 4 -type species.…”

Development of a New Sequential Extraction Procedure of Nickel Species on Workplace Airborne Particulate Matter: Assessing the Occupational Exposure to Carcinogenic Metal Species

“…The speciation of Ni in environmental air samples has been debated for several years, since there are threshold limits values relative to the single species but the analytical techniques for determining them are not always available or easy to use. The speciation of Ni can be obtained through chemical leaching and subsequent analysis of the solutes with traditional methods of Ni determinations or by X-ray determination [27]. In the literature several authors have tried to standardize the leaching process and the contrasting results demonstrate the high variability of the method.…”

Formation of three-dimensional bicontinuous structures via molten salt dealloying studied in real-time by in situ synchrotron X-ray nano-tomography

“…Both the averaged XANES spectra showed a similar profile and edge position as the ones from a metallic Ni standard, which indicates that the porous structure was mainly metallic Ni after dealloying. Note that the XANES spectra did not exhibit the characteristic white line feature prominent in NiO, NiCl 2 , or other NiCl x O y compounds 60 , 61 . The XANES spectrum also does not show a presence of surface oxides on the surface of the dealloyed structure, consistent with our solubility measurements, which show a relatively high solubility (18.5 mol%) of NiO in the MgCl 2 –KCl melt at 800 °C under an inert atmosphere.…”