THE AGGREGATION AND DISPERSION OF ANATASE AND RUTILE TiO2 NANOPARTICLES IN THE PRESENCE OF PHOSPHATE

Titanium dioxide nanoparticles (TiO2 NPs) currently have been used in many fields. However, soil and water environments are inevitably contaminated by the excess of artificial TiO2 NPs. Meanwhile, phosphate is widely present in water body. Therefore, it is important to study the dispersion and aggregation behavior of TiO2 NPs in the presence of phosphate to predict the transport of Tio(2) NPs in aquatic environments. In this study, the dispersion kinetics of anatase and rutile TiO2 NPs (20 nm and 50 nm) in phosphate solution were studied by changing time, particle size, NaNO3 concentration and solution pH. The likely mechanism is investigated using the combination techniques of batch adsorption, Zeta potential and Fourier Transform infra Red. The experimental results indicated that rutile TiO2 NPs are more stable than anatase in solution; and the aggregation of 20 run TiO2 NPs tends to be easier than 50 nm TiO2 NPs. Especially, the dispersion of TiO2 NPs is facilitated by the presence of phosphate due to more negative zeta potential and the stronger repulsive force between nanoparticles.