纳米SiO2和纳米高岭土对阿特拉津的吸附

随着纳米材料的广泛应用,其生态环境效应及其在环境中对有机污染物迁移转化过程的影响逐渐引起人们的重视.应用振荡平衡法研究了纳米SiO2 和纳米高岭土对阿特拉津(AT)的吸附,并讨论了离子强度、吸附剂浓度和pH值对吸附过程的影响.结果表明,纳米SiO2 和纳米高岭土对AT的吸附量都随离子强度的增大而减小.在离子强度 0.001～0.1 mol. L-1 范围内,纳米SiO2 吸附 AT 的 Freundlich 系数 (Kf)由25.55降低到18.35,而纳米高岭土则由85.85降至20.57.不同浓度纳米SiO2:对AT吸附量的影响不明显,而随吸附剂浓度的增高,纳米高岭土吸附AT的Kf由5g·L-1,的71.55降低至20g·L-1 的37.22,浓度效应显著.随着溶液碱性的增强,AT在2种纳米吸附剂上的吸附量明显呈下降趋势. AT的存在形态对其在2种纳米颗粒上的吸附起主导作用.

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.