IFISUR   23398
INSTITUTO DE FISICA DEL SUR
Unidad Ejecutora - UE
artículos
Título:
Geometrical and Electronic Properties of Hydrated Sodium Montmorillonite and Tetracycline Montmorillonite from DFT Calculations
Autor/es:
SILVINA PIRILLO; ROMINA LUNA; IGNACIO LÓPEZ CORRAL; ALFREDO JUAN; MARCELO AVENA
Revista:
JOURNAL OF PHYSICAL CHEMISTRY C
Editorial:
AMER CHEMICAL SOC
Referencias:
Lugar: Washington; Año: 2015 vol. 119 p. 16082 - 16088
ISSN:
1932-7447
Resumen:
The adsorption of fully protonated tetracycline (TC) usingNa-montmorillonite (Na-MMT) as an adsorbent is studied by DFT calculations. Geometric,electronic and magnetic properties are analyzed. To the best of our knowledge,this is the first theoretical DFT research about Na-MMT as an adsorbent of TCcationic specie. Two Na-MMT models are considered: dry and hydrated Na-MMT. The incorporation of fourwater molecules in the interlayer space results in the expansion of the d001 parameter from 10.13 Å (dry)to 12.81 Å (hydrated). Finally, when TC molecule is adsorbed in the basal spaceof MMT, the increment of the d001parameter is about 10 Å respect to hydrated model. Dry and hydrated Na-MMT present a non-magnetic (m = 0 mB)and semiconductor behavior. Nevertheless, the TC-MMT system becomes conductor, andpresents a very important magnetic moment (m = 10.60 μB). After TC adsorption in MMT a potentialvalley with a slight depth in the MMT interlayer is generated. For this reason,it is proposed that TC adsorption would provide active sites for the adsorptionof new species (like Na ions and water molecules.