Fe microenvironments in heat treated rare-earth exchanged montmorillonites

Kuzmann, Erno ✉ [Kuzmann, Ernő (Nukleáris szerkez...), author] Laboratory of Nuclear Chemistry (ML) (ELTE / ELU FoS / IC); Kovács, Eszter M. [Kovács, Eszter Mária (Kémia), author] Fizikai Kémiai Tanszék (UD / IChem); Homonnay, Zoltan [Homonnay, Zoltán (Radiokémia), author] Laboratory of Nuclear Chemistry (ML) (ELTE / ELU FoS / IC); Csákvári, Szabolcs; Klencsár, Zoltán [Klencsár, Zoltán (Mössbauer-spektro...), author] Laboratory of Nuclear Chemistry (ML) (ELTE / ELU FoS / IC); Kónya, Peter [Kónya, Péter (Ásványtan), author] Geological and Geophysical Institute of Hungary; Nagy, Noemi M. [M. Nagy, Noémi (Környezettudomány), author] Fizikai Kémiai Tanszék (UD / IChem); Kónya, Jozsef [Kónya, József (Radiokémia), author] Fizikai Kémiai Tanszék (UD / IChem)

English Scientific Article (Journal Article)
Published: HYPERFINE INTERACTIONS 0304-3843 1572-9540 240 (1) Paper: 87 , 7 p. 2019
  • SJR Scopus - Nuclear and High Energy Physics: Q3
Subjects:
    The rare-earth bentonites were prepared from Ca-bentonite by suspending Ca-bentonite in rare-earth (Ce, La, Y) perchlorate solution. 57Fe Mössbauer spectra of rare earth montmorillonites before heat treatments showed a doublet envelop at room temperature, reflecting dominantly Fe3+ assigned to (cis) octahedral site in the montmorillonite. At the same time, the 80 K spectra of these rare-earth exchanged montmorillonites revealed an additional magnetically split component, too, associated with iron atoms intercalated in the interlayer space. In the case of heat treated samples (250 °C, 360 °C and 500 °C for 4 h), a new doublet component associated with Fe3+ at trans octahedral site, appeared in both the 295 K and 80 K Mössbauer spectra. Powder X-ray diffractometry (XRD) measurements of the heat treated rare earth montmorillonites revealed that a gradual mineral phase transformation of montmorillonite to muscovite occurred upon the applied heat treatments, being consistent with the completing electron magnetic resonance (EMR) and Mössbauer spectroscopy (MS) results.
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    2021-09-20 12:48