Chitosan and Chitosan/Titania Beads for Reactive Red 35 Removal

Abstract

This study investigated the adsorption capacity to remove C.I. Reactive Red 35 by three different adsorbent beads, consisting of pure chitosan and two different chitosan ⁄ titania (TiO₂) composite beads with the TiO₂ being obtained either from the sol-gel method or from added commercial TiO₂ (A100-TiO₂). From the obtained dye adsorption capacities, the chitosan ⁄ TiO₂ composite beads with A100- TiO₂ had the highest adsorption ability to remove reactive dye solution up to 97%, compared to the chitosan ⁄ TiO₂ composite beads with TiO₂ obtained from the sol-gel method (adsorption capacity of 70- 45%). This maybe because the A100-TiO₂ contained in the chitosan ⁄ TiO_2-sol composite beads was in the anatase crystalline form, while the TiO₂ obtained from the sol-gel method did not form a good anatase crystalline form, as shown by X-ray diffraction patterns and SEM micrographs. The crystallization of anatase formed in the composite beads enhanced the adsorption capacity of the composite beads. Pure chitosan adsorbent also showed a good adsorption capacity (95%) due to the electrostatic interactions between chitosan and C.I. Reactive Red 35.