[Sorption of atrazine onto nano-SiO2 and nano-kaolin particles]

With the widespread application of nano-materials, more and more attentions are paid to the potential environmental effects of the nano-materials and their roles in the transport and transformation processes of organic pollutants. The sorption behaviors of atrazine onto nano-SiO2 and nano-kaolin were studied using a batch equilibration method, and the influences of ionic strength, sorbents concentration and pH were also investigated. The results showed that the sorption of atrazine onto nano-SiO2 and nano-kaolin decreased with the increase of ionic strength. Freundlich coefficient (Kf) of nano-SiO2 and nano-kaolin decreased from 25.55 to 18.35 and from 85.85 to 20.57 respectively when ionic strength increased from 0.001 mol x L(-1) to 0.1 mol x L(-1). The variation in concentration of nano-SiO2 had no significant influence on the sorption of atrazine. However, Kf decreased from 71.55 to 37.22 when the concentration of nano-kaolin increased from 5 g x L(-1) to 20 g x L(-1). With the increase of pH, the sorption of atrazine onto the two nano-particles decreased obviously, which indicated the speciation change of atrazine was the dominant factor controlling its sorption processes on two nanoparticles.