Nkedi-Kizza P, Shinde D, Savabi M R, Ouyang Y, Nieves L
Soil and Water Science Department, University of Florida, Gainesville, FL 32611, USA.
J Environ Qual. 2006 Jan 5;35(1):268-76. doi: 10.2134/jeq2005.0140. Print 2006 Jan-Feb.
A batch reactor was used to determine sorption kinetic parameters (k2, F, and K*) and the equilibrium sorption coefficient (K). The two-site nonequilibrium (TSNE) batch sorption kinetics model was used to calculate the kinetic parameters. Two probe organic pesticides, atrazine [2-chloro-4-ethylamino-6-isopropylamino-s-triazine] and diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were studied using three carbonatic soils from South Florida (Chekika, Perrine, and Krome), one noncarbonatic soil from Iowa (Webster), and one organic soil (Lauderhill) from South Florida. Carbonatic soils contained more than 600 g kg(-1) CaCO3. Sorption is initially very fast up to 3 h and then slowly reaches equilibrium. All soil-chemical combinations reached sorption equilibrium after about 24 h and all sorption isotherms were linear. The sorption kinetics data were well described by the TSNE model for all soil-chemical combinations except for the marl soil data (Perrine-Atrazine), which were better described by the one-site nonequilibrium (OSNE) model. Diuron, with higher K, undergoes slower sorption kinetics than atrazine. The Lauderhill soil containing organic carbon (OC) of 450 g kg(-1) exhibited slowest sorption kinetics for both pesticides. An inverse relationship between k3 and K was observed for atrazine and diuron separately in Chekika, Webster, and Lauderhill soils but not in Perrine and Krome soils. The sorption kinetic parameters were used to distinguish the sorption behavior between atrazine and diuron and to identify differences between soils. Normalizing the sorption coefficient (K) to OC showed that atrazine and diuron had K oc values in carbonatic soils that were a third of reported literature values for noncarbonatic soils. Using existing literature K oc values in solute transport models will most likely underestimate the mobility of atrazine, diuron, and other neutral organic chemicals in carbonatic soils.
使用间歇式反应器来确定吸附动力学参数（k2、F和K*）以及平衡吸附系数（K）。采用双位点非平衡（TSNE）间歇吸附动力学模型来计算动力学参数。使用来自南佛罗里达州的三种碳酸盐土壤（切基卡、佩林和克罗姆）、一种来自爱荷华州的非碳酸盐土壤（韦伯斯特）以及一种来自南佛罗里达州的有机土壤（劳德希尔），对两种探针有机农药，即阿特拉津[2-氯-4-乙氨基-6-异丙氨基-s-三嗪]和敌草隆[3-(3,4-二氯苯基)-1,1-二甲基脲]进行了研究。碳酸盐土壤中碳酸钙含量超过600 g kg(-1)。吸附最初在3小时内非常迅速，然后缓慢达到平衡。所有土壤-化学物质组合在约24小时后达到吸附平衡，且所有吸附等温线均为线性。除了泥灰土土壤数据（佩林-阿特拉津）外，TSNE模型能很好地描述所有土壤-化学物质组合的吸附动力学数据，泥灰土土壤数据用单位点非平衡（OSNE）模型描述效果更好。敌草隆的K值较高，其吸附动力学比阿特拉津慢。含有450 g kg(-1)有机碳（OC）的劳德希尔土壤对两种农药的吸附动力学最慢。在切基卡、韦伯斯特和劳德希尔土壤中，分别观察到阿特拉津和敌草隆的k3与K之间呈反比关系，但在佩林和克罗姆土壤中未观察到。吸附动力学参数用于区分阿特拉津和敌草隆之间的吸附行为，并识别土壤之间的差异。将吸附系数（K）归一化为有机碳表明，阿特拉津和敌草隆在碳酸盐土壤中的Koc值是文献报道的非碳酸盐土壤值的三分之一。在溶质运移模型中使用现有的文献Koc值很可能会低估阿特拉津、敌草隆和其他中性有机化学品在碳酸盐土壤中的迁移性。
