Muendo Boniface M, Shikuku Victor O, Getenga Zachary M, Lalah Joseph O, Wandiga Shem O, Rothballer Michael
Department of Chemical Science and Technology, Technical University of Kenya, P.O Box 52428-00200, Nairobi, Kenya.
Kenya Bureau of Standards, P.O. Box 54974-00200, Nairobi, Kenya.
Heliyon. 2021 Feb 8;7(2):e06073. doi: 10.1016/j.heliyon.2021.e06073. eCollection 2021 Feb.
In this work, the adsorption-desorption dynamics of diuron in three typical Kenyan agricultural soils, Nzoia (NZ), Thika (TH) and Machakos (MK) was investigated. The equilibrium adsorption data, tested against three classical nonlinear adsorption isotherms, was best described by the Freundlich model. The Freundlich adsorption constant, (K), increased in the order MK > TH > NZ soil. Additionally, the negative Gibb's free energy values indicate the adsorption processes were thermodynamically spontaneous and physical. Multiple linear regression analysis indicated that the adsorption-desorption behavior was controlled by the clay and phosphorus contents of the soil. Phosphorus negatively affected the adsorption of diuron and promoted desorption. The groundwater ubiquity score (GUS) indicated that diuron movement rating in MK soil was 'moderate' while the movement in TH and NZ soils was 'high'.
在这项研究中，对三种典型的肯尼亚农业土壤——恩佐亚（NZ）、锡卡（TH）和马查科斯（MK）中敌草隆的吸附-解吸动力学进行了研究。针对三种经典非线性吸附等温线测试的平衡吸附数据，用弗伦德利希模型描述最佳。弗伦德利希吸附常数（K）按MK > TH > NZ土壤的顺序增大。此外，吉布斯自由能负值表明吸附过程在热力学上是自发的且为物理吸附。多元线性回归分析表明，吸附-解吸行为受土壤黏土和磷含量的控制。磷对敌草隆的吸附有负面影响并促进解吸。地下水普遍存在性评分（GUS）表明，敌草隆在MK土壤中的迁移评级为“中等”，而在TH和NZ土壤中的迁移为“高”。
