Title: Sorption Modeling And Soil-Property Controls On Imidacloprid Adsorption In Organically Amended Soils
Authors: Anyim
P.B.
Tukura
B.W.
Anifowose
O.
Okibe
P.O.
Bello
Z.S.
Alozie
A.C.
Volume: 10
Issue: 1
Pages: 1-9
Publication Date: 2026/01/28
Abstract:
This study investigated how organic amendments, specifically biochar, poultry manure, and cow dung, affect the adsorption behaviour of imidacloprid in agricultural soils from the Lafia region of Nasarawa State, Nigeria. Surface soil collected from 0-15 cm was amended at 10% (w/w) and assessed using batch equilibrium techniques across imidacloprid concentrations ranging from 10 to 50 mg/L. Physicochemical properties, including pH, organic carbon, cation exchange capacity, and electrical conductivity, were quantified using standard laboratory methods. Adsorption parameters (C?, q?, and Kd) were evaluated using the Freundlich and BET isotherm models. The findings showed that biochar-amended soil achieved the greatest adsorption capacity and highest distribution coefficients, followed by poultry manure and cow dung, with all amended treatments demonstrating superior performance relative to the unamended control. Adsorption efficiency decreased at higher imidacloprid concentrations, suggesting progressive saturation of available binding sites. The BET model provided an excellent fit for all treatments (Rē = 0.957-0.983), confirming that multilayer adsorption dominated, whereas the Freundlich model was less representative. Correlation analysis further indicated strong positive relationships between adsorption indices (q? and Kd) and both organic carbon and cation exchange capacity, highlighting their critical role in enhancing pesticide retention. In contrast, electrical conductivity and pH were negatively associated with adsorption performance, suggesting an inhibitory effect on sorption.