Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Intercalation of N-methylformamide in kaolinite: In situ monitoring by near-infrared spectroscopy and X-ray diffraction
Δημιουργός/Συγγραφέας:	Andreou, Fevronia T. Barylska, Barbara Ciesielska, Zuzanna Szczerba, Marek Derkowski, Arkadiusz [EL] Γκιώνης, Βασίλης[EN] Gionis, Vassilis Siranidi, Eirini [EL] Χρυσικός, Γεώργιος Δ.[EN] Chryssikos, Georgios D.
Ημερομηνία:	2021
Γλώσσα:	Αγγλικά
ISSN:	01691317
DOI:	10.1016/j.clay.2021.106209
Περίληψη:	The selective self-assembly of small molecules in the interlayer of kaolinite is a fundamentally important and technologically relevant process, typically studied ex situ by X-ray diffraction (XRD). Near-infrared (NIR) spectroscopy is now introduced to provide a complementary local structural description of intercalation with improved control of experimental conditions. New NIR- and XRD-based proxies were developed and applied to the real-time monitoring of N-methylformamide (NMF) intercalation in two reference kaolinites differing in stacking order. The commonly employed XRD-based formalism was found to overestimate reaction progress. The bonding of NMF in the interlayer was independent of reaction progress and kaolinite type. Both NIR and XRD recorded identical sigmoidal kinetics. Isothermal NIR monitoring (25–80 ◦C) yielded time-temperature superimposable sigmoidals with an apparent activation energy of ~60 kJ/mol, common to both samples. All NIR and XRD data series could be described as linear combinations of empty and fully intercalated kaolinite. The filling of the interlayer was too fast to be observed. The sigmoidal curves were instead modeled as the log-normally distributed response of an ensemble of intercalating entities, presumably crystallites. The multiplicative standard deviation of the distribution, which determines its steepness, is a sample-specific, temperature-independent property of kaolinite.
Τίτλος πηγής δημοσίευσης:	Applied Clay Science
Τόμος/Κεφάλαιο:	212
Σελίδες:	106209
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry [EL] Φασματοσκοπία[EN] Spectroscopy
Λέξεις-Κλειδιά:	Kaolinite N-methylformamide Intercalation Near-infrared spectroscopy (NIR) X-ray diffraction (XRD) Kinetics
EU Grant identifier:	MIS 5002409
Κάτοχος πνευματικών δικαιωμάτων:	© 2021 Elsevier B.V. All rights reserved.
Σημειώσεις:	The NIR study is part of FA's Master thesis defended in October 2020 at the National Technical University of Athens and available at http://dx.doi.org/10.26240/heal.ntua.19974. Professors Y. Raptis and A. Kiritsis are thanked for their valuable comments. FA acknowledges the financial support from the project “Advanced Materials and Devices” (MIS 5002409) of TPCI/NHRF which was implemented under the “Action for the Strategic Development on the Research and Technological Sector”, funded by the Operational Program “Competitiveness, Entrepreneurship and Innovation” (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund). All other work at NHRF was supported with funds of the Applied Spectroscopy Laboratory of TPCI. Work at PAS was supported by an internal grant of the Institute of Geological Sciences.
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο