纳米TiO2颗粒与腐殖酸和SDBS的相互作用机制

Interaction mechanisms of the TiO2 nanoparticles with humic acid and SDBS

摘要:

为保障水环境生态安全性及纳米技术的可持续发展,研究了纳米TiO₂颗粒与腐殖酸（HA）和十二烷基苯磺酸钠（SDBS）的相互作用,考察了pH、离子浓度对其相互作用的影响.结果表明,腐殖酸和十二烷基苯磺酸钠均会抑制纳米颗粒的聚集,增强颗粒的迁移能力.pH和离子浓度对相互作用有显著的影响.当溶液的pH接近等电点时,纳米颗粒表面带正电荷,因电荷屏蔽效应,HA和SDBS在颗粒表面的吸附量增大；随着IS的增加,由于双电层压缩作用, HA及SDBS在纳米TiO₂表面的吸附量也不断增加.最后,讨论了纳米TiO₂颗粒与HA及SDBS的相互作用机制,即可分为聚集、接近和强相互作用3个步骤.同时比较了HA和SDBS与纳米TiO₂颗粒相互作用机制的不同.

Abstract:

To ensure the aquatic environment security and promote the sustainable development of nanotechnology, the interactions between nanomaterials and environmental nanopollutants (humic acid and sodium dodecyl benzene sulfonate) were investigated. The effects of the surrounding solution chemistry (pH and ionic strength) on the interaction were discussed. The results suggested that the interaction between nanomaterials and environmental nanopollutants could inhibit the aggregation of nanoparticles, and then enhance their mobility in aquatic environments. The interaction was affected by pH and ionic strength. The absorbed content of humic acid and SDBS on the surface of TiO₂ nanoparticles increased near the pHpzc (point zero of charge) due to the charge screening effect. It also increased with the increasing ionic strength due to the compression of the electric double layer. The interaction mechanisms between nanomaterials and environmental nanopollutants were discussed. The interaction process could be divided into three processes, including aggregation, approaching and strong interaction. The differences of interaction mechanisms between humic acid and SDBS were also discussed.