农药西维因及敌草隆在草木灰上的吸附行为研究

Sorption characteristics of sevin and diuron on plant ash

测定分析了草木灰的孔隙结构、表面性质及化学组成,选择理化参数接近,空间构型不同的2种农药西维因和敌草隆作为吸附质,研究其在草木灰上吸附行为,结果表明两者在草木灰上吸附模式理截然不同,线性吸附方程及准一级动力学方程能够拟合平面型分子西维因的吸附等温线及动力学曲线,Freundlich吸附等温式及二级动力学方程吸附对非平面型分子敌草隆的等温线及动力学曲线拟合程度最高,说明平面型分子的吸附可能以简单的线性分配为主,而非平面型分子可能以多过程非线性吸附为主;等温线及动力学拟合参数显示,草木灰对平面型分子西维因的吸附量远大于非平面型分子敌草隆,说明吸附质分子的空间位阻效应是影响吸附的重要因素.

Pore structure, surface property and chemical constitution of plant ash were determined. Two pesticides-sevin and diuron whose physicochemical properties were close, but steric configurations were different, were chosen as sorbates. Their sorption isotherms and kinetics on plant ash were examined, respectively. Their sorption models were significantly varied. Linear model and pseudo one-stape dynamics equation could fit the sorption of planar sevin on plant ash, implying that its sorption possibly was simple linear partition process. Freundlich model and two-stape dynamics equation fitted best the sorption of non-planar diuron on plant ash, implying that its sorption was complex multi-process. The sorption isotherm and kinetic fitting parameters indicated that the sorption capacity of planar sevin was larger than that of non-planar diuron, suggesting that the steric effect of sorbate molecule played important role on sorption.