【作者】 刘永红；

【导师】 董元彦；

【作者基本信息】 华中农业大学 ， 农药学， 2005， 硕士

【摘要】 随着磺酰脲类除草剂的大量广泛施用,其环境行为逐渐引起科学工作者的关注。本文研究了两种可变电荷土壤和三种人工合成的铁铝氧化物对磺酰脲类除草剂——苄嘧磺隆（bensulfuron-methyl, BSM）的吸附,以及pH、Zn²⁺离子对供试样品吸附苄嘧磺隆的影响,并对供试样品吸附苄嘧磺隆的动力学特征进行了分析。同时,用傅立叶变换红外光谱（FT-IR）、X-衍射（XRD）、热解重量分析（TG）等手段对合成的铁铝氧化物及其吸附BSM的情况进行了表征。同时用高效液相色谱（HPLC）分析测定了BSM。实验结果表明: 用Langmuir、Freunlich、Terkim等方程对供试样品吸附BSM的数据进行了拟合,发现供试样品吸附苄嘧磺隆的等温曲线较好地符合Freundlich方程。它们的吸附曲线大致可分为两种:一种是随着苄嘧磺隆浓度的升高吸附量快速增加,另一种是随着苄嘧磺隆浓度的升高其吸附量缓慢增加,最终均有达到吸附平衡的趋势。 供试样品吸附苄嘧磺隆的量均随溶液的pH的升高而逐渐减小,但是,氧化物和土壤随pH的变化趋势不一样,主要是由于这两类供试样品的结构和组成不同而产生的。 加入Zn²⁺离子后,赤红壤吸附苄嘧磺隆的吸附量较未加Zn²⁺有小幅度增加;而氧化物吸附苄嘧磺隆的量较未加Zn²⁺之前有较大幅度的增加,但是氧化物之间有较明显的差异。吸附Zn²⁺后,铝氧化物吸附苄嘧磺隆的量随Zn²⁺的浓度的增加而减小;铁氧化物吸附苄嘧磺隆的量随Zn²⁺的浓度的增加而增加。 用0级动力学方程、一级动力学方程、抛物线扩散方程、Elovich方程、双参数方程等拟合供试样品吸附苄嘧磺隆的动力学数据。结果表明:一级动力学方程可以较好地用来描述供试样品对苄嘧磺隆的吸附动力学特征。 苄嘧磺隆在供试样品上的吸附动力学研究表明:苄嘧磺隆在土壤中的吸附量随温度的升高而小幅升高,而在铝氧化物中的吸附量随温度的升高而减少。 根据一级动力学方程对供试样品吸附苄嘧磺隆的数据进行分析,发现苄嘧磺隆在不同的供试样品中的吸附定速步骤不相同。低温时,红壤吸附苄嘧磺隆的定速步骤是颗粒扩散,而赤红壤和铝氧化物的定速步骤是膜扩散。高温时,红壤吸附苄嘧磺隆的定速步骤是化学反应和颗粒扩散,赤红壤的定速步骤是化学反应和膜扩散,更多还原

【Abstract】 With the wild use of sulfonylurea herbicides, the scientists paid more attention to their environmental behaviors gradually. An adsorption study on bensulfuron-methyl (BSM) on three synthsized metal oxides and two variable charge soils, and the effects of pH, metal ion Zn2+ on tested samples, have been carried out. The characteristics of adsorption kinetics have been investigated using the static, stirred and vortex batch techniques for GZ-soil (Guangzhou Soil), HN-soil (Hunan Soil) and Al oxide. At the same time, the morphologys and characteristics of the oxides and the surface adsorbed BSM were characterized with the techniques of FT-IR, XRD, TG At the same time, the BSM was analyzed with HPLC. The results showed:The forms of isotherms of BSM adsorption by soils and oxides were two types: One was that the magnitude of BSM adsorption increased rapidly as the concentration of BSM increased, the other was that the magnitude of BSM adsorption increased slowly with the increase concentration of BSM, and at last their equilibriums were reached. The data of the BSM adsorption by soils and oxides were discribed with the Langmuir Freundlich terkim equations. Compared with these equations, the Freundlich isotherm equation was the optional one. The other models in point were Langmuir terkim equations. The magnitude of BSM adsorption is as follows: hematite<GZ-soil<goethite<HN-soil<Al oxide.Within the range of BSM concentrations, the magnitude of BSM adsorption on the tested samples descreased with increase in pH of the solution; and the magnitude of BSM adsorption increased with increase in concentration of BSM. When different concentrations of Zn2+ were added into the tested samples, the effect of the Zn2+ was different. The amount of BSM adsorption on soil decreased comparing with that of without Zn2+. However, the magnitude of BSM adsorption on oxides increased largely. The tendencys of increase or decrease were different because of their characteristics and composition.The zero-order equation, first-order equation, parbolic diffusion equation,double-parameter equation quation, Elovich equation were typed for discribing the static, stirred and vortex batch techniques kinetics of BSM adsorption on three tested samples. The results showed that the adsorption data could be satisfactorily described with the first-order equation. For Al oxide, the amount of BSM adsorption descreased, and the soils increased with the raising of temperature, respectively. Compared with these equations, first-order equation was the optional one. The other equations in point were zero-order equation, parbolic diffusion equation, double parameter equation quation, Elovich equation.According to the kinetic plot for the adsorption of BSM on tested samples, it can be seen that the amount of BSM adsorbed increased with in temperature of the system on tested soils samples. On Al oxide, however, the tendency was opposite.Kinetics of BSM adsorption was investigated on Al oxide and two soils using the static, stirred and vortex batch techniques. Observed rate coefficients obtained from static, stirred and vortex batch systems were combined and used to calculate rate coefficients for film diffusion (Jcp), intraparticle diffusion (kp), and reaction kinetics (Icr) in a static system. This study elucidates that, in low temperature (28 °C), in GZ-soil and HN-soil, film diffusion was rate-determinding step. In Al oxide, High temperature (38’C), reaction kinetics was the rate-limiting step.The study on bensulfuron-methyl could offer scientific basis for how to effectively use the pesticide and reduce the pollution. At the same time, it would assess their mobility, transformation, and would take effective and scientific measures to monitor and manage the contamination, to repair the soil environment更多还原