Testing of kaolinite/TiO ₂ nanocomposites for methylene blue removal: photodegradation and mechanism

Abstract This study investigated the effect of different treatment conditions on kaolinite-halloysite type as a support for TiO 2 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 TiO 2 photocatalyst, the morphology and structure of kaolinite/TiO 2 composites can significantly improve their ability to adsorb organic pollutants and their photocatalytic activity: The photocatalytic efficiency of kaolinite/TiO 2 was evaluated by degrading the textile dye methylene blue (MB) under UV-light irradiation. The results showed an improvement from 71 % using TiO 2 to 98 % for nanocomposites kaolinite/TiO 2 using samples amount of 1 g/L and Co = 20 mg/L.