Abstract

The expanded perlite (aluminosilicate naturally acid) has been modified with orthophenanthroline (Lewis base). The material was characterized by TG/DTA, XRD and IR. The thermogravimetric curve of the modified expanded perlite presented a lower thermal stability due to the orthophenanthroline and showed 13,6% of mass loss total. However, pure expanded perlite presented only 2,3% of the mass loss. The DTA curve showed endothermic event characteristic of the presence of orthophenanthroline. For XRD analysis is visualized, the presence of reflections in the diffractogram relating to the modified material of orthophenanthroline peaks of crystallinity since no modification perlite is an amorphous material. The band regarding absorption vibration of Si-O group appears at lower wavenumbers than in the unmodified material. So there was an interaction between the OH groups of silanols of perlite groups with unshared electron pairs of nitrogen atoms and C=C bonds (also rich in electrons) in the chemical structure of orthophenanthroline as a result of a hydrogen bond between these groups. thus perlite was modified through the interaction of its acid sites (Si-OH) with Lewis basic sites of orthophenanthroline.

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