Synthesis, characterization and photocatalytic activity of TiO sub(2) supported natural palygorskite microfibers

• Published in: Applied clay science Vol. 52; no. 3; pp. 301 - 311
• Main Authors: Bouna, L, Rhouta, B, Amjoud, M, Maury, F, Lafont, M-C, Jada, A, Senocq, F, Daoudi, L
• Format: Journal Article
• Language: English
• Published: 01.05.2011
• Subjects: Anatase; Fibers; Nanomaterials; Nanostructure; Oranges; Photocatalysis; Synthesis; Titanium dioxide
• ISSN: 0169-1317
• DOI: 10.1016/j.clay.2011.03.009

This study deals with the synthesis of TiO sub(2) supported Moroccan palygorskite fibers and their use as photocatalyst for the removal of Orange G pollutant from wastewater. The TiO sub(2)-palygorskite nanocomposite synthesis was accomplished according to a colloidal route involving a cationic surfactant as template (hexadecyltrimethylammonium bromide) assuring hence organophilic environment for the formation of TiO sub(2) nanoparticles. The clay minerals samples were characterized before and after functionalization with TiO sub(2). Anatase crystallizes above ca. 450 degree C and remarkably remains stable up to 900 degree C. In contrast, pure TiO sub(2) xerogel obtained from titanium tetraisopropoxide (TTIP) showed before calcination a nanocrystalline structure of anatase. By increasing the temperature, anatase readily transforms into rutile beyond 600 degree C. The remarkable stability at high temperature of anatase particles immobilized onto palygorskite microfibers was due to the hindrance of particles growth by sintering. Homogeneous monodisperse distribution of anatase particles with an average size of 8 nm was found by TEM and XRD onto palygorskite fibers. This anatase particle size remains below the nucleus critical size (ca. 11 nm) required for anatase-rutile transition. The TiO sub(2) supported palygorskite sample annealed in air at 600 degree C for 1 h exhibits the highest photocatalytic activity towards the degradation of Orange G compared to nanocomposite samples prepared under different conditions as well as pure TiO sub(2) powders obtained from the xerogel route or commercially available as Degussa P25.