Adsorption-Desorption Mechanism of Synthesized Benzimidazole Based Fungicide 2-(3’-Pyridyl) On Selected Soil Minerals

Abstract

The adsorption and desorption phenomena of synthesized Benzimidazole based fungicide, 2-(3’-pyridyl) benzimidazole (PyBlm), was investigated by batch equilibrium method. Four soil minerals were utilized for the sorption studies including; alumina, silica, muscovite and montmorillonite. The highest value of adsorption coefficient (K_d(ads)) was obtained for montmorillonite mineral (Mx (Al, Fe, Mg₄) Si₈O₂₀ (OH₄)) was 2779 µg ml^-1. The highest rate of adsorption is attributable to its considerably large surface area of 628 m²g^-1 and highest inter-lattice d-spacing, 10 Å. Highest desorption (K_d(des)) was also observed in montmorillonite mineral (21.45 µg ml^-1). Montmorillonite thus displayed increased sorption capacity for PyBlm among all tested minerals. Hysteresis coefficient ranged from 0.58 to 3. The results were statistically evaluated by using one-way analysis of variance (ANOVA). Furthermore, statistical evaluation done with the help of Minitab 17 expressed the good fitting of the obtained results which was shown by means of residual plots. Current research which is suggestive of the variable adsorption and desorption of PyBlm expresses the profound dependence of PyBlm interaction on the physicochemical characteristics of the selected minerals. All minerals except montmorillonite expressed poor adsorption signifying the percolation of PyBlm through them towards the lower soil profiles. Results obtained in the present research marks the favorability of montmorillonite in firmly interacting with the PyBlm molecules and thus alleviating the possibility of PyBlm percolation to lower soil profiles.