State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
J Environ Sci (China). 2010;22(8):1195-202. doi: 10.1016/s1001-0742(09)60238-2.
The aggregation and dispersion behaviors of carbon nanotubes (CNTs) can regulate the environmental spread and fate of CNTs, as well as the organic pollutants adsorbed onto them. In this study, multi-walled carbon nanotubes (MWNTs) and single-walled carbon nanotubes (SWNTs) were surface modified with humic acids from different sources and with surfactants of different ionic types. The dispersion stability of surface modified CNTs was observed by UV-Vis spectrophotometry. The effect of humic acid and surfactant dispersion on the adsorption of atrazine by CNTs was investigated by batch equilibrium experiments. Both humic acid and surfactant could effectively disperse MWNTs, but not SWNTs, into stable suspensions under the studied conditions. Surface modified CNTs had a greatly reduced capacity for adsorption of atrazine. The inhibitory effect of peat humic acid was relatively stronger than that of soil humic acid, but the two surfactants had a similar inhibitory effect on atrazine adsorption by the two CNT types. Increases in surfactant concentration resulted in rapid decreases in the adsorption of atrazine by CNTs when the surfactant concentration was less than 0.5 critical micelle concentration.
碳纳米管（CNTs）的聚集和分散行为可以调节 CNTs 在环境中的扩散和归宿，以及吸附在其上的有机污染物。在本研究中，采用不同来源的腐殖酸和不同离子类型的表面活性剂对多壁碳纳米管（MWNTs）和单壁碳纳米管（SWNTs）进行了表面改性。通过紫外可见分光光度法观察了表面改性 CNTs 的分散稳定性。通过批量平衡实验研究了腐殖酸和表面活性剂分散对 CNTs 吸附莠去津的影响。在研究条件下，腐殖酸和表面活性剂都可以有效地将 MWNTs 分散成稳定的悬浮液，但不能将 SWNTs 分散成稳定的悬浮液。表面改性 CNTs 对莠去津的吸附能力大大降低。泥炭腐殖酸的抑制作用相对较强，而两种表面活性剂对两种 CNT 类型吸附莠去津的抑制作用相似。当表面活性剂浓度小于 0.5 临界胶束浓度时，表面活性剂浓度的增加会导致 CNTs 对莠去津的吸附迅速下降。
