Transport and competitive sorption-desorption of glyphosate and Triton X-100 in diverse agricultural soils under high flow rates and various concentration ratios

An inverse model based on the maximum likelihood method, incorporating various sorption–desorption isotherms, was applied to column experiments to capture the single and competitive sorption–desorption and leaching of glyphosate and Triton X-100 in agricultural soils with varying organic–inorganic content. The study simulates high irrigation or heavy rainfall to evaluate chemical behaviour under intense leaching, accounting for compound interactions, concentration ratios, and flow rates within equilibrium and kinetic frameworks. Results show Triton X-100′s transport is largely unaffected by glyphosate, whereas its presence significantly reduces glyphosate’s sorption and retardation, slightly decreasing overall soil sorption capacity (soil A 7%, B 5%, C 10%, D 6%). Kinetic Langmuir models capture time-dependent sorption–desorption dynamics most accurately (R2 > 0.85). Soil mineralogy (Albite, Illite, Kaolinite) and metal content (Al, K, Fe) enhance glyphosate sorption, retardation, and tailing, but have minimal effect on Triton X-100. Doubling the concentration ratio reduced glyphosate’s kinetic sorption coefficient by up to 10% and overall sorption capacity by 16%, while increasing flow rate from 2 to 3 mL/min decreased the sorption coefficient by 20%, slightly increased desorption, and reduced sorption capacity from ∼36% to 16%. Results ultimately show sorption–desorption behaviour under high-flow competitive conditions depends strongly on environmental factors and cannot be generalized across scenarios.