Insight into the adsorption mechanisms of ionizable imidazolinone herbicides in sediments: Kinetics, adsorption model, and influencing factors
Insight into the adsorption mechanisms of ionizable imidazolinone herbicides in sediments: Kinetics, adsorption model, and influencing factors
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深入了解沉积物中可电离咪唑啉酮除草剂的吸附机制：动力学、吸附模型和影响因素
DOI：
10.1016/j.chemosphere.2021.129655
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发表时间：
2021-02-02
期刊：
影响因子：
8.8
通讯作者：
Tan, Huihua
中科院分区：
文献类型：
--
作者：
Hu, Mingfeng;Liu, Li;Tan, Huihua
为揭示咪唑啶氧、咪唑烟酸和咪唑乙烟酸在沉积物上的吸附机理，进行了静态吸附实验。3种咪唑啉酮类除草剂在沉积物上的吸附动力学均符合准二级动力学模型（R-2 > 0.9004）。3种除草剂的吸附容量（Q（e.cal））为0.0183 ~ 0.0859mg·kg ~（-1）。3种除草剂在沉积物上的吸附均在24 h内达到平衡，符合Freundlich模型（R-2 > 0.9561）。3种除草剂在沉积物上的吸附系数K-F值在0.2501 ~ 1.322L-1/n mg（1-1/n）kg（-1）之间。结果表明，颗粒内扩散和颗粒外传质是除草剂在沉积物上吸附的主要速率控制步骤，化学吸附在吸附过程中占主导地位。原始沉积物中咪唑安定、咪唑烟酸和咪唑乙烟酸的滞后系数H分别为0.9422、0.7877和0.744，表明其解吸存在滞后性。考察了溶液pH和沉积物有机碳含量对咪唑啉酮类除草剂吸附行为的影响。结果表明，沉积物对除草剂的吸附过程具有很强的pH依赖性，吸附效率与沉积物有机质含量密切相关，说明静电作用在沉积物对咪唑啉酮类除草剂的吸附行为中起着重要作用，除草剂主要被沉积物的非晶态物质吸附。这些研究结果对于评估咪唑啉酮类除草剂在水-沉积物系统中的归趋和迁移具有重要意义。(C)2021爱思唯尔有限公司版权所有。
To reveal the adsorption mechanisms of imazamox, imazapic, and imazethapyr on sediment and batch experiments were carried out in this study. The adsorption kinetics of three imidazolinone herbicides on sediment were accurately described by the pseudo-second-order kinetic model(R-2 > 0.9004). The values of adsorption capacity (Q(e.cal)) were ranged from 0.0183 to 0.0859 mg kg(-1) for three herbicides. Adsorption equilibrium was reached within 24 h for three herbicides on sediment, and well fitted by the Freundlich model(R-2 > 0.9561). The K-F of values for adsorption obtained sediment samples were ranged from 0.2501 to 1.322 L-1/n mg(1-1/n) kg(-1)for three herbicides. These results indicated that intraparticle diffusion and external mass transport were the main rate controlling steps of the adsorption of herbicides on sediment and that the chemical adsorption was dominant during the adsorption processes. The calculated hysteresis coefficient H were 0.9422,0.7877 and 0.744 for imazmox, imazapic and imazethapyr in raw sediment, respectively, indicating that there is a hysteresis in desorption. The influences of solution pH and sediment organic carbon content on the imidazolinone herbicide adsorption behaviors were also examined. Which shown that the adsorption process for herbicides was highly pH-dependent and adsorption efficiency was closely related to the organic matter content of the sediment, suggesting that electrostatic interactions played crucial roles in the adsorption behavior between sediment and imidazolinone herbicides, and the herbicides were mostly absorbed by the amorphous materials of sediment. These research findings are important for assessing the fate and transport of imidazolinone herbicides in wateresediment systems. (C) 2021 Elsevier Ltd. All rights reserved.