吸附反应时间对除草剂阿特拉津吸附行为的影响

采用批量动态实验方法,对潮土中阿特拉津吸附特征随吸附反应时间变化进行了研究。结果表明,土壤吸附的阿特拉津量随反应时间的变化符合双曲线函数关系。在50μg·L-1～2000μg·L-1浓度系列下,在48h内,土壤颗粒对阿特拉津的吸附属于快反应,土壤吸附的阿特拉津量随吸附反应时间呈指数上升,为吸附实验结束(168h)时土壤吸附阿特拉津总量的58%到90%。当吸附反应时间超过48h后,随反应时间增加,土壤吸附阿特拉津量差异变化不显著。阿特拉津在潮土颗粒和土壤溶液中的相分配可用Freundlich方程描述。吸附容量因子Kf与吸附反应时间之间有极显著的线性正关系(r2=0.9063**,p<0.0001)。无量纲的非线性因子n与吸附反应时间之间也具有显著的线性负关系(r2=0.5666*,p=0.0192)。

Effect of sorption reaction time on sorption behavior of herbicide atrazine

Atrazine, the most widely used herbicide in the world, has been used as a pre-and post-emergent herbicide to control broad-leaf weeds in the production of corn and sorghum. Atrazine is frequently detected in groundwater, surface waters, and precipitation. Kinetic batch experiments were carried out in order to investigate the characteristics of atrazine adsorption in fluvo-aquic soil with the change of adsorption contact time. The atrazine adsorbed by soil at 48 h, with atrazine initial concentrations increasing, account for 58% to 90% of the total adsorption amount of atrazine at 168 h, while adsorption contact time is beyond 48 h, the differences in amount of atrazine adsorbed by soil are not significant. The distribution relationships of atrazine between soil particles and solution can be described using Freundlich equation. Impact of sorption contact time on characterization of atrazine adsorbed by soil is evaluated by interpreting temporal variations in Freundlich sorption isotherm parameters obtained from the phase distribution relationships. The Freundlich capacity factor, Kf, highly significantly positively linearly increased as sorption contact period increase with r2=0.906 3 (p<0.000 1). However, the negatively linear correlation is observed for the linearity factor, n, with contact times increasing with r2=0.566 6 (p=0.019 2).