Changes on structural and magnetic properties of maghemite nanoparticles during their coverage with MCM-41
Registro en:
Fellenz, Nicolás A., Perez de Berti, Ignacio O., Soldati, Analía L., Stewart, Silvana J., Marchetti, Sergio G., et al. (2015). Changes on structural and magnetic properties of maghemite nanoparticles during their coverage with MCM-41. Elsevier; Ceramics International; 41; 10B; pp. 15057-15066
0272-8842
Autor
Fellenz, Nicolás A.
Perez de Berti, Ignacio O.
Soldati, Analía L.
Stewart, Silvana J.
Marchetti, Sergio G.
Bengoa, Jose F.
Institución
Resumen
Fil: Fellenz, Nicolás A. Universidad Nacional de Río Negro; Argentina Fil: Perez de Berti, Ignacio O. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Perez de Berti, Ignacio O. Centro Científico Tecnológico La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentina Fil: Soldati, Analía L. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina Fil: Stewart, Silvana J. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Stewart, Silvana J. Centro Científico Tecnológico La Plata. Instituto de Física La Plata; Argentina Fil: Marchetti, Sergio G. Consejo Nacional de Investigaciones Científicas y Técnicas. Fil: Marchetti, Sergio G. Centro Científico Tecnológico La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentina Fil: Bengoa, Jose F. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Bengoa, Jose F. Centro Científico Tecnológico La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentina si This work reports a simple synthesis of a mesoporous ordered silica structure (MCM-41) grown up around pre-synthesized maghemite nanoparticles. A composite with magnetic response and high specific surface area was obtained adding maghemite nanoparticles coated with oleic acid in the synthesis gel of MCM-41 and finally calcining in air. Different characterizations techniques such as magnetic measurements, Mössbauer spectroscopy at 25 and -260 °C and transmission electron microscopy were used to study the magnetic and structural changes of the initial maghemite nanoparticles produced during its coverage with the mesoporous silica structure. The presence of the mesoporous structure inhibits the expected transformation from maghemite to hematite when the system was calcined in air at 510 °C. It was established that a sintering of the nanoparticles during the calcination step occurs, leading to a magnetization saturation value similar to that of the bulk compound. In order to evaluate the capability as adsorbent, the magnetic composite was subjected to a surface amino-functionalization and then tested for Cr(VI) and Cu(II) adsorption from water.