Effect of the agglomeration of TiO2 nanoparticles on their photocatalytic performance in the aqueous phase

Abstract TiO 2 nanoparticles have been widely explored as photocatalysts in the degradation of organic matters present in water. However, spontaneous agglomeration of TiO 2 nanoparticles in a suspension is a crucial issue that must be addressed before the photocatalyst can be used for water treatment. In the present work, the nature of the agglomeration of TiO 2 nanoparticles in aqueous suspension was investigated. Two approaches to minimize the agglomeration of colloidal TiO 2 particles were investigated. A careful control over the pH of the system was found to be an effective method for stabilizing colloidal TiO 2 particles and to significantly enhance the adsorption of orange II. As a result, the overall photocatalytic degradation rate was greatly accelerated. In addition to pH control, modification of TiO 2 particles using polyelectrolyte poly allylamine hydrochloride (PAH) was observed to be an effective approach for preventing colloidal TiO 2 particles from agglomeration.