TY - JOUR AU - Kuzmann, Ernő AU - Kovács, Eszter Mária AU - Homonnay, Zoltán AU - Csákvári, Szabolcs AU - Klencsár, Zoltán AU - Kónya, Péter AU - M. Nagy, Noémi AU - Kónya, József TI - Fe microenvironments in heat treated rare-earth exchanged montmorillonites JF - HYPERFINE INTERACTIONS J2 - HYPERFINE INTERACT VL - 240 PY - 2019 IS - 1 PG - 7 SN - 0304-3843 DO - 10.1007/s10751-019-1622-7 UR - https://m2.mtmt.hu/api/publication/30782621 ID - 30782621 N1 - Funding Agency and Grant Number: Eotvos Lorand University (ELTE); NKFIH OTKA [K115913, K115784, K131963, K120265]; Hungarian-Croatian ST [TET_16-1-2016-0002]; EU - European Regional Development Fund [GINOP-2.3.2-15-2016-00008] Funding text: Open access funding provided by Eotvos Lorand University (ELTE). The financial supports from NKFIH OTKA (No. K115913, K115784, K131963, and K120265) and Hungarian-Croatian S&T (No TET_16-1-2016-0002) as well as by the EU and co-financed by the European Regional Development Fund under the project GINOP-2.3.2-15-2016-00008 grants are acknowledged. Z.K. expresses thanks to Prof. Ferenc Simon (Institute of Physics, Budapest University of Technology and Economics, Budapest, Hungary) for making available the applied spectrometer for recording the EMR spectra. Funding Agency and Grant Number: Eotvos Lorand University (ELTE); NKFIH OTKAOrszagos Tudomanyos Kutatasi Alapprogramok (OTKA) [K115913, K115784, K131963, K120265]; Hungarian-Croatian ST [TET_16-1-2016-0002]; EU - European Regional Development FundEuropean Union (EU) [GINOP-2.3.2-15-2016-00008] Funding text: Open access funding provided by Eotvos Lorand University (ELTE). The financial supports from NKFIH OTKA (No. K115913, K115784, K131963, and K120265) and Hungarian-Croatian S&T (No TET_16-1-2016-0002) as well as by the EU and co-financed by the European Regional Development Fund under the project GINOP-2.3.2-15-2016-00008 grants are acknowledged. Z.K. expresses thanks to Prof. Ferenc Simon (Institute of Physics, Budapest University of Technology and Economics, Budapest, Hungary) for making available the applied spectrometer for recording the EMR spectra. Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary Imre Lajos Isotope Laboratory, Department of Physical Chemistry, University of Debrecen, Debrecen, Hungary Centre for Energy Research, HAS, Budapest, Hungary Geological and Geophysical Institute of Hungary, Budapest, Hungary Export Date: 5 February 2021 CODEN: HYIND Correspondence Address: Kuzmann, E.; Institute of Chemistry, Hungary; email: kuzmann@caesar.elte.hu Funding details: European Commission, EC Funding details: TÉT_16-1-2016-0002 Funding details: European Regional Development Fund, FEDER, GINOP-2.3.2-15-2016-00008 Funding text 1: Open access funding provided by Eötvös Loránd University (ELTE). The financial supports from NKFIH OTKA (No. K115913, K115784, K131963, and K120265) and Hungarian-Croatian S&T (No TÉT_16-1-2016-0002) as well as by the EU and co-financed by the European Regional Development Fund under the project GINOP-2.3.2-15-2016-00008 grants are acknowledged. Z.K. expresses thanks to Prof. Ferenc Simon (Institute of Physics, Budapest University of Technology and Economics, Budapest, Hungary) for making available the applied spectrometer for recording the EMR spectra. AB - 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. LA - English DB - MTMT ER - TY - JOUR AU - Kuzmann, Ernő AU - Singh, LH AU - Garg, VK AU - de Oliveira, AC AU - Kovács, Eszter Mária AU - Molnár, ÁM AU - Homonnay, Zoltán AU - Kónya, Péter AU - M. Nagy, Noémi AU - Kónya, József TI - Mössbauer study of the effect of rare earth substitution into montmorillonite JF - HYPERFINE INTERACTIONS J2 - HYPERFINE INTERACT VL - 237 PY - 2016 IS - 1 PG - 8 SN - 0304-3843 DO - 10.1007/s10751-016-1225-5 UR - https://m2.mtmt.hu/api/publication/3030404 ID - 3030404 N1 - N1 Funding Details: A127/2013, CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Institute of Physics, University of Brasília, Brasília DF, 70919-970, Brazil Institute of Chemistry, Eötvös Loránd University, Budapest, 1117, Hungary Isotope Laboratory, Department of Colloid and Environmental Chemistry, University of Debrecen, Debrecen, Hungary Geological and Geophysical Institute of Hungary, Hungary, 1143, Hungary Cited By :8 Export Date: 5 February 2021 CODEN: HYIND Correspondence Address: Kuzmann, E.; Institute of Chemistry, Hungary; email: kuzmann@caesar.elte.hu Funding details: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES, A127/2013 Funding details: Hungarian Scientific Research Fund, OTKA, K115913, K115784 Funding text 1: The financial supports from the CAPES (No A127/2013) and OTKA (No K115913 and K115784) grants are acknowledged. E.K. thanks to Dr. P. Kovacs-Palffy for the valuable discussion. AB - Novel montmorillonites were prepared by the exchange of the interlayer cations with a series of rare earth cations (La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, and Er) and characterized by XRD, XRF, SEM, chemical analysis and 57Fe Mössbauer spectroscopy. An unexpected magnetically split component, assigned to iron being in the interlayer space, was observed in the Mössbauer spectra at 78K in some rare earth cation exchanged montmorillonite. This paper is the initial report about this observation. The transition of iron from the octahedral site to the interlayer and possible incorporation of rare earths in sites different from those which are in the interlayer space was concluded. © 2016, Springer International Publishing Switzerland. LA - English DB - MTMT ER -