Cr(VI) immobilization in mixed (Mg, Al) oxides
Por:
Martinez-Gallegos S., Pfeiffer H., Lima E., Espinosa M., Bosch P., Bulbulian S.
Publicada:
1 ene 2006
Resumen:
In the reaction sequence of thermal decomposition of chromate exchanged hydrotalcite a spinel structure was detected at 800 °C; the main compound was a periclase-like structure. At 1000-1200 °C the only compounds were MgO and the spinel MgAl1.3Cr0.7O4. The particle size and morphology did not change with gamma irradiation or thermal treatments. The composition of the spinels MgAl2-xCrxO4 varies when samples are irradiated and/or thermally treated. Aluminum in octahedral sites is displaced to tetrahedral sites as chromium is incorporated into spinels. A molecular dynamics simulation of the spinels reproduced the experimental behaviour. A mechanism based on thermodynamical data and Wagner reactions is proposed. © 2006 Elsevier Inc. All rights reserved.
Filiaciones:
Martinez-Gallegos S.:
Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, C.P. 11801 México, DF, Mexico
Facultad de Ciencias, Universidad Autónoma del Estado de México, Instituto Literario 100, C.P. 50000, Toluca, Edo. de México, Mexico
Pfeiffer H.:
Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Ciudad Universitaria, C.P. 04510 México, DF, Mexico
Lima E.:
Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Ciudad Universitaria, C.P. 04510 México, DF, Mexico
Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, C.P. 09340 México, DF, Mexico
Espinosa M.:
Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, C.P. 11801 México, DF, Mexico
Bosch P.:
Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Ciudad Universitaria, C.P. 04510 México, DF, Mexico
Bulbulian S.:
Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, C.P. 11801 México, DF, Mexico
|