Testing of kaolinite/TiO2 nanocomposites for methylene blue removal: photodegradation and mechanism
Résumé
This study investigated the effect of different treatment conditions on kaolinite-halloysite type as a support for TiO2 and their potential application in photocatalysis. These nanocomposites are used to study the photodegradation of methylene blue, a dye widely used in the textile industry and released into the environment. Crystal structure, specific surface area, pore structure and the morphology of kaolinite were all studied using XRD, attenuated total reflectance (ATR), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and ultraviolet-visible light. The optical band gap increased with increasing kaolin loading from 2.93 to 3.14 eV. Compared with pure TiO2 photocatalyst, the morphology and structure of kaolinite/TiO2 composites can significantly improve their ability to adsorb organic pollutants and their photocatalytic activity: The photocatalytic efficiency of kaolinite/TiO2 was evaluated by degrading the textile dye methylene blue (MB) under UV-light irradiation. The results showed an improvement from 71 % using TiO2 to 98 % for nanocomposites kaolinite/TiO2 using samples amount of 1 g/L and Co = 20 mg/L.