Dispersion and aggregation of nanoparticles in aqueous solutions are important factors for safe application of nanoparticles. In this study, dispersion and aggregation of nano-TiO2 in aqueous solutions containing vari...Dispersion and aggregation of nanoparticles in aqueous solutions are important factors for safe application of nanoparticles. In this study, dispersion and aggregation of nano-TiO2 in aqueous solutions containing various anions were investigated. The influences of anion concentration and valence on the aggregation size, zeta potential and aggregation kinetics were individually investigated. Results showed that the zeta potential decreased from 19.8 to-41.4 mV when PO4^（3-） concentration was increased from 0 to 50 mg/L, while the corresponding average size of nano-TiO2 particles decreased from 613.2 to 540.3 nm. Both SO4^（2-） and NO3^-enhanced aggregation of nano-TiO2in solution. As SO4^（2-） concentration was increased from 0 to 500 mg/L, the zeta potential decreased from 19.8 to 1.4 mV, and aggregate sizes increased from 613.2 to 961.3 nm.The trend for NO3^- fluctuation was similar to that for SO4^（2-） although the range of variation for NO3^- was relatively narrow. SO4^（2-） and NO3^-accelerated the aggregation rapidly, while PO4^（3-） did so slowly. These findings facilitate the understanding of aggregation and dispersion mechanisms of nano-TiO2 in aqueous solutions in the presence of anions of interest.展开更多
基金supported by the International S&T Cooperation Program of China(No.2015DFG92750)the National Natural Science Foundation of China(No.51478172)the Department of Science and Technology of Hunan Province(No.2014GK1012)
文摘Dispersion and aggregation of nanoparticles in aqueous solutions are important factors for safe application of nanoparticles. In this study, dispersion and aggregation of nano-TiO2 in aqueous solutions containing various anions were investigated. The influences of anion concentration and valence on the aggregation size, zeta potential and aggregation kinetics were individually investigated. Results showed that the zeta potential decreased from 19.8 to-41.4 mV when PO4^（3-） concentration was increased from 0 to 50 mg/L, while the corresponding average size of nano-TiO2 particles decreased from 613.2 to 540.3 nm. Both SO4^（2-） and NO3^-enhanced aggregation of nano-TiO2in solution. As SO4^（2-） concentration was increased from 0 to 500 mg/L, the zeta potential decreased from 19.8 to 1.4 mV, and aggregate sizes increased from 613.2 to 961.3 nm.The trend for NO3^- fluctuation was similar to that for SO4^（2-） although the range of variation for NO3^- was relatively narrow. SO4^（2-） and NO3^-accelerated the aggregation rapidly, while PO4^（3-） did so slowly. These findings facilitate the understanding of aggregation and dispersion mechanisms of nano-TiO2 in aqueous solutions in the presence of anions of interest.
