Iron Speciation in Different Saharan Dust Advections and Effect of the Procedural Blank on the Results From X-ray Absorption Spectroscopy and Selective Leaching Experiments

In this work, we applied X-ray Absorption Spectroscopy (XAS) and selective leaching experiments for investigating iron speciation in different dust advections collected on different unwashed quartz fiber filters. XAS analysis evidenced a predominance of Fe(III) in 6-fold coordination for Saharan dust and a trend towards Fe(II) and 4-fold coordination in the order: Saharan dust, mixed Saharan, and non-Saharan aerosol samples. The role of the sampling substrate was evaluated explicitly, including in the analysis a set of blank filters. We were able to pinpoint the possible contribution to the overall XAS spectrum of the residual Fe on quartz as the concentration decrease towards the blank value. In particular, the filter substrate showed a negligible effect on the structural trend mentioned above. Furthermore, selective leaching experiments evidenced a predominance of the residual fraction on Fe speciation and indicated the lowest Fe concentrations for which the blank contribution is <20% are 1 μ g for the first three steps of the procedure (releasing the acid-labile, reducible and oxidizable phases, respectively) and 10 μ g for the last step (dissolving the insoluble residuals).

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Iron Speciation of Natural and Anthropogenic Dust by Spectroscopic and Chemical Methods

Atmosphere ◽

10.3390/atmos10010008 ◽

2018 ◽

Vol 10 (1) ◽

pp. 8 ◽

Cited By ~ 7

Author(s):

Chiara Petroselli ◽

Beatrice Moroni ◽

Stefano Crocchianti ◽

Roberta Selvaggi ◽

Riccardo Vivani ◽

...

Keyword(s):

Absorption Spectroscopy ◽

Steel Production ◽

Insoluble Fraction ◽

Saharan Dust ◽

Test Results ◽

Chemical Methods ◽

X Ray ◽

Different Types ◽

Leaching Experiments ◽

X Ray Absorption

In this work, we have characterized the iron local structure in samples of two different types of atmospheric dust using X-ray absorption spectroscopy and selective leaching experiments. Specifically, we have investigated samples of long-range transported Saharan dust and freshly emitted steel plant fumes with the aim of individuating possible fingerprints of iron in the two cases. Findings include (1) prevalence of octahedral coordinated Fe 3 + for all samples; (2) presence of 6-fold coordinated Fe 3 + , aluminosilicates and iron oxy(hydr)oxides in Saharan dust and (3) of Fe-bearing spinel-like structures in the industrial fumes; (4) general predominance of the residual insoluble fraction with a notable difference: 69% for Saharan dust and 93% for steel production emissions, associated with aluminosilicates and non-reducible iron oxy(hydr)oxides, and Fe spinels, respectively. The remarkable differences between the X-ray absorption spectroscopy (XAS) spectra and leaching test results for the two sample types suggest the possibility to exploit the present approach in more complex cases. To this aim, two additional case studies of mixed aerosol samples are presented and discussed.

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Cu- and Fe-speciation in a composite zeolite catalyst for selective catalytic reduction of NOx: insights from operando XAS

Catalysis Science & Technology ◽

10.1039/d0cy01654c ◽

2021 ◽

Author(s):

Ilia A. Pankin ◽

Houeida Issa Hamoud ◽

Kirill A. Lomachenko ◽

Søren Birk Rasmussen ◽

Andrea Martini ◽

...

Keyword(s):

Selective Catalytic Reduction ◽

Absorption Spectroscopy ◽

Zeolite Catalyst ◽

Catalytic Reduction ◽

Mechanical Mixture ◽

X Ray ◽

Fe Speciation ◽

Reduction Of Nox ◽

Operando Xas ◽

X Ray Absorption

Cu-SAPO-34 (Cu-CZC) and Fe-mordenite (Fe-MOR) and their mechanical mixture (50 : 50) have been exhaustively investigated by means of operando X-ray absorption spectroscopy under NH3-SCR conditions.

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