Determination of Total Acid in Palygorskite Chemically Modified by N-Butylamine Thermodesorption

• Main Authors: Ruiz Juan A.C., Melo Dulce M.A., Souza José R., Alcazar Leopoldo O.
• Format: Article
• Language: English
• Published: Associação Brasileira de Metalurgia e Materiais (ABM); Associação Brasileira de Cerâmica (ABC); Associação Brasileira de Polímeros (ABPol) 2002-01-01
• Series: Materials Research
• Subjects: palygorskite; lanthanum; thermodesorption; acid catalyst
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392002000200014

The acid properties of palygorskite clay (R1) were studied using n-butylamine as probe molecule. A comparison was made of these properties in palygorskite clay (R1), in an acidified palygorskite (R2) and in acid palygorskite loaded with 2% of lanthanum (R3). The total acid properties were determined by FTIR (Fourier Transform Infrared) and TG-DTA (thermogravimetry). The acidity increased as follows: R3>R2>R1. The acid strength sites were classified as physisorbed, weak, medium and strong. The acid treatment did not change the site distribution, apparently only removing channel impurities. The introduction of lanthanum created many more acid sites and increased the specific area. Both weak and strong sites, which increased significantly, were considered new active acid sites produced by the lanthanum.