【作者】 崔昕； 张俊燕； 张微； 常娜； 江树人； 潘灿平；

【Author】 CUI Xin , ZHANG Jun-yan, ZHANG Wei, CHANG Na, JIANG Shu-ren , PAN Can-ping (College of Sciences, China Agricultural University, Beijing 100094, China)

【机构】 中国农业大学理学院；

【摘要】 对thifensulfuron-methyl在土壤中的降解行为进行了研究,不同年度的田间试验结果表明thifensulfuron-methyl在酸性红壤土中的半衰期为0.92~1.23d,降解速率受土壤有机质含量、pH值和温度的影响。采用平衡振荡法测定了噻吩磺隆在三种不同土壤中的吸附行为,结果表明,其吸附过程均符合经典的Freundlich模型,吸附常数在0.3854~3.4274之间。根据土壤有机吸附常数和吸附自由能的大小,推测其在3种土壤中均以物理吸附为主。通过对吸附常数Kf与土壤有机质含量、粘土含量和pH值的关系进行分析,发现土壤有机质含量、粘土含量和pH值在吸附过程中能影响噻吩磺隆的吸附性,Kf与土壤有机质含量、粘土含量呈正相关,与土壤pH值呈负相关。同时还研究了thifensulfuron-methyl和腐植酸的吸附作用,利用平衡法测定吸附等温线,评价了pH值和离子强度对其吸附的影响,同时借助FT-IR手段对其吸附机理进行了初步探讨,结果发现,thifensulfuron-methyl与腐植酸有很强的吸附作用,吸附常数为684.16,与pH值成显著负相关,随着离子强度的增加,吸附常数有一定的增加,但变化不明显。IR光谱分析推测thifensulfuron-methyl与腐植酸在相互作用过程中形成了氢键。更多还原

【Abstract】 The degradation dynamics of thifensulfuron-methyl in soil were investigated. The field experiments in two years showed that the half-lives of thifensulfuron-methyl in red soil were 0.92~1.23d respectively. The dynamics of thifensulfuron-methyl in soil were influenced by organic mattter content of soil , pH and temperature. The adsorption of thhifensulfuron-methyl in three different soils was investigated by using the batch equilibration method. The results showed that the adsorption isotherms of the soils fitted the Freundlich equation well, with range from 0.3854 to 3.4274. Further analysis of K f and the free energy of sorption (ΔG) indicate that adsorption of thifensulfuron-methyl with soil was mainly due to physical behaviour in three types of soil. Furthermore, the K f increased with increasing organic matter and clay content of soils and decreased with increasing pH, indicate that OM, clay contents and the soils pH were the dominating factors influencing the thifensulfuron-methyl retention in all of the systems. The adsorption of thifensulfuron-methyl on HA (humic acid) was studied also using the batch equilibration and the technique of FT-IR (Fourier transform infrared) was used to detected adsorption mechanisms, evaluating the pH and ionic strength. The results showed that K f of the adsorption on HA was 684.16, which negatively related with pH, positively related with ion concentration, but was less distinct than pH. The result of IR showed that the hydrogen bonding is the main mechanism of thifensulfuron-methyl adsorption with HA.更多还原