表面活性剂对二嗪磷在不同土壤中吸附迁移的影响

采用批量平衡法和薄层层析法, 分别研究了不同浓度的3种表面活性剂十二烷基苯磺酸钠(SDBS)、Tween 80和十六烷基三甲基溴化胺(CTAB) 对二嗪磷在湖南省具有代表性的6大土类、9种不同母质土壤中吸附和迁移性能的影响. 结果表明, SDBS能够明显地降低各种土壤对二嗪磷的吸附, 促进二嗪磷的迁移作用, 并且吸附平衡系数(Kd)、比移值(Rf)分别随SDBS浓度增大而增大、减小.浓度成显著的负相关和正相关关系.Tween-80和CTAB对二嗪磷在土壤中的吸附和迁移表现出一定的相似性, Tween-80浓度在0.1~2倍临界胶束浓度(CMC)范围内(CTAB浓度为0.80~87.43 mg·L-1), 其Kd值、Rf值分别随表面活性剂浓度增大而增大、减小, 而Tween-80浓度在2~5倍临界胶束浓度的范围内(CTAB浓度为87.43~191.60 mg·L-1.), 则出现与之相反的变化趋势.

Effects of surfactants on the behavior of diazinon in different soils

The effects of three different surfactants (SDBS, Tween-80 and CTAB) on the adsorption and mobility of diazinon were studied in nine soil types, using batch equilibrium experiments and soil thin layer chromatography. The soils had different physical properties and included the six representational soil types in Hunan province. SDBS significantly reduced the adsorption and accelerated the mobility of diazinon in a variety of soils. The adsorption coefficient (Kd) was negatively correlated with the concentration of SDBS while the mobility factors (Rf) were positively correlated with the SDBS concentration. Tween-80 and CTAB had similar effects on the adsorption and mobility of diazinon from 0.1CMC to 2CMC (CTAB 0.80~87.43mg·L-1). In both cases, the Kd and Rf showed positive correlation and negative correlations with the surfactant concentration, respectively. However, the opposite trend appeared from 2CMC to 5CMC (CTAB 87.43~191.60mg·L-1).