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为评价氯胺嘧草醚的环境安全性,采用批量平衡法测定了氯胺嘧草醚在5种土壤中的吸附-解吸行为,并运用数学模型对其吸附-解吸特性及移动性能进行了分析。结果表明:氯胺嘧草醚在5种土壤中的等温吸附-解吸曲线符合Freundlich模型,吸附常数(Kf值)范围在6.991~18.49之间;不同土壤对其的吸附作用强弱依次为:黑土>水稻土>褐土>潮土>红土。氯胺嘧草醚在5种土壤中的有机碳吸附常数(KOC)范围在704.4~1 579之间,推测其在土壤中具有低移动性;薄层层析试验也表明,氯胺嘧草醚在土壤中的移动性较弱。氯胺嘧草醚在5种土壤中的吸附自由能绝对值均小于40 k J/mol,表明其吸附机理主要是物理吸附。其Kf值与土壤有机质含量、黏粒含量呈正相关,而与土壤p H值呈负相关。解吸试验表明,氯胺醚在其中3种土壤中的解吸过程存在滞后现象。研究表明,在正常使用情况下,氯胺嘧草醚不易对地表水或地下水造成污染风险。
In order to evaluate the environmental safety of chlorambucil, the adsorption and desorption behaviors of chlorimuronet in five soils were determined by batch equilibrium method. The adsorption-desorption characteristics and mobility of chlorambucil were also analyzed using mathematical models . The results showed that isothermal adsorption-desorption curve of chlorimuron in five soils accorded with Freundlich model, and the adsorption constants (Kf value) ranged from 6.991 to 18.49. The adsorption capacity of different concentrations of soil was as follows: black soil > Paddy soil> Cinnamon soil> Chao soil> laterite. The KOC values of chlorimuron-ethyl in the five soils ranged from 704.4 to 1579, suggesting that it had low mobility in soil. Thin-layer chromatography also showed that chlorimuron-ethyl Weak in the soil. The absolute values of adsorption free energy of chlorimuron in the five soils were less than 40 kJ / mol, indicating that the adsorption mechanism was mainly physical adsorption. The Kf value was positively correlated with soil organic matter content and clay content, but negatively correlated with soil p H value. Desorption tests showed that there was a lag in the desorption of chloramines in three soils. Studies have shown that, under normal conditions, the use of chlordiazepoxide is not easy to pollute surface or groundwater.