Sorption kinetics of fipronil on soils

Sorption kinetics of fipronil was studied on five soils of varying physico-chemical properties by batch equilibration method. Fipronil sorption on soils conformed to pseudo-second order kinetics and both the initial uptake rate and rate constant had a significant and positive correlation with clay content. The sorption kinetics of fipronil onto soils could be explained by intraparticle diffusion model consisting of an initial faster step followed by later slower step. The intraparticle diffusion rate constants for the initial faster and later slower step showed a significant and positive correlation with clay content (r = 0.978, significant at p ≤ 0.01) and soil electrical conductance (r = 0.901, significant at p ≤ 0.05), respectively.