Department of Agronomic and Forest Sciences, Universidade Federal Rural Do Semi-Árido, Mossoro, Rio Grande do Norte, Brazil.
Environ Monit Assess. 2021 Mar 16;193(4):194. doi: 10.1007/s10661-021-08948-9.
The speed of the sorption reaction alters the bioavailability of herbicides in the soil and, consequently, the transport and transformation processes of the molecule in the environment. In this research, the sorption kinetics of sulfometuron-methyl was evaluated in different Brazilian soils in which sugarcane is grown. The sorption speed was carried out by the batch equilibrium method. The amount of sulfometuron-methyl adsorbed and remaining in the soil solution was used to build kinetic models in fifteen soils. Pearson's correlation coefficients were determined between maximum sorption capacity and soil properties. The pseudo-second-order model presented the best fit to report the sorption kinetics of sulfometuron-methyl in soils. The sorption equilibrium time varied between 69.1 and 524.7 min. The properties of cation exchange capacity (CEC), soil hydrogenionic potential (pH), and total organic carbon (TOC) affected the sorption kinetics of sulfometuron-methyl. The pH showed a negative correlation with the maximum adsorption capacity at equilibrium, while TOC and CEC positively correlated with the maximum adsorption. The results demonstrate that the sorption speed of sulfometuron-methyl varies between soils; this must be considered when defining the rate of use of the herbicide for weed control, minimizing the risk of environmental contamination.
吸附反应的速度改变了土壤中除草剂的生物利用度，进而影响了分子在环境中的迁移和转化过程。本研究评估了磺酰脲甲酯在巴西不同种植甘蔗的土壤中的吸附动力学。采用间歇平衡法进行吸附速度实验。利用吸附在土壤溶液中的磺酰脲甲酯的量和剩余量，在十五种土壤中建立了动力学模型。测定了最大吸附容量与土壤性质之间的皮尔逊相关系数。拟二级模型最适合描述磺酰脲甲酯在土壤中的吸附动力学。吸附平衡时间在 69.1 至 524.7 分钟之间变化。阳离子交换容量（CEC）、土壤氢离子势能（pH）和总有机碳（TOC）的性质影响磺酰脲甲酯的吸附动力学。pH 值与平衡时的最大吸附容量呈负相关，而 TOC 和 CEC 与最大吸附量呈正相关。结果表明，磺酰脲甲酯的吸附速度在不同土壤之间存在差异；在确定除草剂的使用速率以控制杂草时，必须考虑到这一点，以最大程度地降低环境污染的风险。
