Bio-adsorption of triadimenol pesticide from aqueous solutions using activated sludge of dairy plants

Abstract: In the present study, activated sludge has been utilized for the removal of triadimenol pesticide from water. The maximum adsorption capacity was 42.9 mg triadimenol per gram activated sludge obtained at 298 K. The equilibrium data were fitted to Langmuir Freundlich models and it was found that Freundlich model best fit these data with regression coefficient R²=0.947. The kinetic data showed that the rate of triadimenol adsorption is increased with increasing the initial concentration and mixing speed, while decreased with increasing temperature. The two-resistance mass transfer model based on the film resistance homogeneous solid-phase diffusion was used to fit the experimental data. A computer program has been developed to estimate the theoretical concentration–time- dependent curves and to compare them with the experimental curves by means of the best-fit approach. The model predicts that the external mass transfer coefficient k_f was affected by varying the initial triadimenol concentration, the agitation speed and temperature, whereas the diffusion coefficient D_e was affected by the initial triadimenol concentration and temperature.