@article{MTMT:30388793, title = {EPR Analysis of Fe3+ and Mn2+ Complexation Sites in Fulvic Acid Extracted from Lignite}, url = {https://m2.mtmt.hu/api/publication/30388793}, author = {Klencsár, Zoltán and Köntös, Zoltán}, doi = {10.1021/acs.jpca.8b00477}, journal-iso = {J PHYS CHEM A}, journal = {JOURNAL OF PHYSICAL CHEMISTRY A}, volume = {122}, unique-id = {30388793}, issn = {1089-5639}, year = {2018}, eissn = {1520-5215}, pages = {3190-3203}, orcid-numbers = {Klencsár, Zoltán/0000-0003-0175-7024} } @article{MTMT:3208553, title = {Preparation and structure's analyses of lanthanide (Ln) -exchanged bentonites}, url = {https://m2.mtmt.hu/api/publication/3208553}, author = {Kovács, Eszter Mária and Baradács, Eszter and Kónya, Péter and Kovács-Pálffy, P and Harangi, Sándor and Kuzmann, Ernő and Kónya, József and M. Nagy, Noémi}, doi = {10.1016/j.colsurfa.2017.02.085}, journal-iso = {COLLOID SURFACE A}, journal = {COLLOIDS AND SURFACES A : PHYSICOCHEMICAL AND ENGINEERING ASPECTS}, volume = {522}, unique-id = {3208553}, issn = {0927-7757}, abstract = {The interaction between Lanthanides (Ln)- ions and Ca-bentonite and the structural changes accompanying were studied. Ln-exchanged bentonites were prepared from Ca-bentonite (Istenmezeje, Hungary) by ion exchange in three consecutive washings with lanthanide solutions. Scanning Eletronmicroscopy Energy Dispersive X-ray spectroscopy (SEM-EDX) studies showed even distribution of Lns and other components of bentonite. The natural bentonite and the lanthnide exchanged bentonites were characterized by X-ray diffraction (XRD), which revealed the same mineral composition, and the increase of the basal spacing of montmorillonite from 1.465 (Ca2+) to 1.577 nm (REE3+). The d001 basal spacing of lanthanide montmorillonite increases as the ion radius of the lanthanide cation increases. The Fe3+, and Lns3+ amount on the bentonite were determined by X-ray-fluorescence spectrometry (XRF) elemental analysis. The amount of exchanged Lns were determined by washing the Ln-bentonite with 1 M ammonium-acetate, and measuring the amount of Ln released, using inductively coupled plasma optical emission spectrometry (ICP-OES). In most Ln-bentonites, the quantity of the exchanged Ln ions was about 80–90% of the cation exchange capacity (CEC) of the bentonite. In case of some lanthanides bentonite (La3+, Ce3+, and Gd3+), however, the sorbed quantity of lanthanum ions was higher than the cation exchange capacity. In case of lanthanum-bentonite, the lanthanide quantity is as high as 136% of CEC. Moreover, the iron(III) content of lanthanum bentonite is less than that of the original Ca-bentonite. Mössbauer spectra of the La-, Ce-, and Gd-exchanged samples at 78 K revealed an unexpected magnetically split component that was absent from the Ca-bentonite. This component may belong to interlayer Fe. This iron can be released from the octahedral positions crystal lattice. © 2017 Elsevier B.V.}, keywords = {WATER; X-ray diffraction; scanning electron microscopy; MONTMORILLONITE; TURKEY; CENTRAL ANATOLIA; CLAY-MINERALS; kaolinite; sorption; Earth; GENESIS; Inductively coupled plasma optical emission spectrometry; X-ray-fluorescence spectrometry; Complexometric titration; Ln-bentonites}, year = {2017}, eissn = {1873-4359}, pages = {287-294}, orcid-numbers = {Kovács, Eszter Mária/0000-0002-3117-2521; Kuzmann, Ernő/0000-0002-0183-6649} } @article{MTMT:3097530, title = {Mössbauer study of pH dependence of iron-intercalation in montmorillonite}, url = {https://m2.mtmt.hu/api/publication/3097530}, author = {Kuzmann, Ernő and Garg, VK and Singh, H and de Oliveira, AC and Pati, SS and Homonnay, Zoltán and Rudolf, M and Molnár, ÁM and Kovács, Eszter Mária and Baranyai, Edina and Kubuki, S and M. Nagy, Noémi and Kónya, József}, doi = {10.1007/s10751-016-1314-5}, journal-iso = {HYPERFINE INTERACT}, journal = {HYPERFINE INTERACTIONS}, volume = {237}, unique-id = {3097530}, issn = {0304-3843}, abstract = {57Fe Mössbauer spectroscopy and XRD have successfully been applied to show the incorporation of Fe ion into the interlayer space of montmorillonite via treatment with FeCl 3 in acetone. The 78K 57Fe Mössbauer spectra of montmorillonite samples reflected magnetically split spectrum part indicating the intercalation of iron into the interlayer of montmorillonite via the treatment with FeCl 3+acetone and washed with water until the initial pH=2.3 increased to pH=4.14. It was found that the occurrence of intercalated iron in the form of oxide-oxihydroxide in montmorillonite increases with the pH. Intercalation was confirmed by the gradual increase in the basal spacing d001 with pH. © 2016, Springer International Publishing Switzerland.}, keywords = {pH dependence; Ca-montmorillonite; 57Fe Mössbauer spectroscopy; Interlayer Fe}, year = {2016}, eissn = {1572-9540}, orcid-numbers = {Kuzmann, Ernő/0000-0002-0183-6649; Homonnay, Zoltán/0000-0001-5299-5394; Kovács, Eszter Mária/0000-0002-3117-2521} } @article{MTMT:3030404, title = {Mössbauer study of the effect of rare earth substitution into montmorillonite}, url = {https://m2.mtmt.hu/api/publication/3030404}, author = {Kuzmann, Ernő and Singh, LH and Garg, VK and de Oliveira, AC and Kovács, Eszter Mária and Molnár, ÁM and Homonnay, Zoltán and Kónya, Péter and M. Nagy, Noémi and Kónya, József}, doi = {10.1007/s10751-016-1225-5}, journal-iso = {HYPERFINE INTERACT}, journal = {HYPERFINE INTERACTIONS}, volume = {237}, unique-id = {3030404}, issn = {0304-3843}, abstract = {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.}, keywords = {Mössbauer-spectroscopy; Bentonite; Rare earth substitution; Interlayer Fe}, year = {2016}, eissn = {1572-9540}, orcid-numbers = {Kuzmann, Ernő/0000-0002-0183-6649; Kovács, Eszter Mária/0000-0002-3117-2521; Homonnay, Zoltán/0000-0001-5299-5394} } @article{MTMT:1354713, title = {Incorporation of Fe in the interlayer of Na-bentonite via treatment with FeCl3 in acetone}, url = {https://m2.mtmt.hu/api/publication/1354713}, author = {Komlosi, A and Kuzmann, Ernő and M. Nagy, Noémi and Homonnay, Zoltán and Kubuki, S and Kónya, József}, doi = {10.1346/CCMN.2007.0550107}, journal-iso = {CLAY CLAY MINER}, journal = {CLAYS AND CLAY MINERALS}, volume = {55}, unique-id = {1354713}, issn = {0009-8604}, abstract = {The effect of FeCl3 in acetonic medium on the structure of Na-bentonite was studied using X-ray diffraction (XRD), Fe-57 Mossbauer spectroscopy, X-ray fluorescence spectroscopy and infrared spectroscopy to describe the structure of the bentonite before and after treatment. In the samples treated with FeCl3, an increase in the basal spacing was found by XRD, while a new magnetically split component assigned to Fe3+ incorporated within the interlayer regions of montmorillonite showed up in the low-temperature Mossbauer spectra. The Mossbauer parameters observed were close to those of Fe oxyhydroxides, suggesting the presence of some kind of nanoparticles. These results show that the treatment with acetonic FeCl3 solution is an effective method for introducing Fe into montmorillonite in the form of Fe3+ accommodated in the interlayer region. The treated samples proved to be efficient Lewis catalysts in the acylation of aldehydes (benzaldehyde and 4-OH-benzaldehyde) by acetic acid anhydride.}, year = {2007}, eissn = {1552-8367}, pages = {89-95}, orcid-numbers = {Kuzmann, Ernő/0000-0002-0183-6649; Homonnay, Zoltán/0000-0001-5299-5394} } @article{MTMT:117882, title = {User-Friendly Software for Mössbauer-Spectrum Analysis}, url = {https://m2.mtmt.hu/api/publication/117882}, author = {Klencsár, Zoltán and Kuzmann, Ernő and Vértes, Attila}, doi = {10.1007/BF02055410}, journal-iso = {J RADIOANAL NUCL CHEM}, journal = {JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY}, volume = {210}, unique-id = {117882}, issn = {0236-5731}, year = {1996}, eissn = {1588-2780}, pages = {105-118}, orcid-numbers = {Klencsár, Zoltán/0000-0003-0175-7024; Kuzmann, Ernő/0000-0002-0183-6649} }