Study of the effects of lanthanum and the iron ion on the acidic properties of Al-pillared vermiculite

• Autor(a) principal: Fernandes,Marcus Venicio da Silva
• Data de Publicação: 2013
• Outros Autores: Silva,Lindomar Roberto Damasceno da
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Materials research (São Carlos. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392013000500033
• topic: acidity; mesoporous clay; lanthanum

The synthesis of porous materials has attracted interest for decades due to their applications in catalysis and gas adsorption. Clay obtained by insertion of mesoporous oligomer [La xAl13-xO4 (OH)24 (H2O)12]7 + (where x equals the molar amount of lanthanum), followed by calcination, may cause variation in the acidic properties. The analyzes showed that increasing the amount of La on oligomer results in a higher acidity shown in the spectrum a characteristic band in the region of 1445 and 1545cm-1 to Lewis and Brönsted respectively, predominantly of the last one. The Mössbauer spectroscopy results showed a relationship between increased symmetry of the octahedral site of iron (Fe3+) and increased lanthanum doping, and consequently a sharp increase in acidity.