Sorption Of Atrazine Onto Nano-particles And Their Humic Coated Complexs

In this paper, the sorption and desorption behaviors of atrazine onto nano-SiO2 and nano-kaolin were studied. Humic acids from different sources were used to investigate the effect of natural organic matter on the properties of nano-SiO₂ and nano-kaolin. The sorption of atrazine onto humic acid coated nano-particles complexs were compared with that onto pure nano-particles. The influences of ionic strength,sorbents concentration,pH and temperature were systematically elucidated. Physical and chemical properties of different sorbents were analyzed for interpreting sorption mechanisms.The results showed that the sorption of humic acids and atrazine onto nano-SiO₂ and nano-kaolin were non-linear, and the sorption isotherms could be fitted by Fruendlich equation. Hysteresis was observed for the desorption of atrazine from nano-SiO2 and nano-kaolin. With the increase of ionic strength, the sorption of humic acids increased, but the sorption of atrazine decreased. The variation in concentration of nano-SiO₂ had no significant influence on the sorption of atrazine. However, Kf decreased when the concentration of nano-kaolin increased. Sorption of atrazine increased on nano-SiO2 but decreased on nano-kaolin when temperature increased. With the increase of pH, the sorption of humic acids and atrazine on the two nano-particles decreased obviously. Sorption of atrzine onto humic acid coated nano-particle complexs was lower than onto corresponding original nano-particles. In addition, higher aromaticity of humic acid was in favor of the sorption of atrazine. The sorption of atrazine onto both nano-particles was decreased with the increases of ionic strength and pH.Nano-particles have greater sorption capability than ordinary particles because of lower particle size and huge specific surface area. In nature water environment, sorption of humic matters on nano-particles change the sorption of organic pollutants on nano-particles. Many factors like Physical and Chemical Propertie of sorbents, concentration of sorbents, temperature, ionic strength, pH and nature organic matters change the behavior and fate of organic pollutants in nature water environment.