Study of the Adsorption of Difenoconazole on Char in Aqueous Medium

This study focuses on the use of a new plastic waste polythene terephthalate (PET) adsorbent in a physico-chemical process for liquid effluent treatment. First, the char was characterized by determining the iodine and methylene blue indices as well as the zero charge point. The experimental conditions were optimized by evaluating the influences of pH, adsorption kinetics, char mass and initial concentration of difenoconazole. The results of the characterization revealed that the zero charge point was less than 7 (6.66), the iodine and methylene blue indices were equal to 689 mg/g and 315 mg/g respectively. Adsorption studies showed a better elimination of difenoconazole under acidic conditions, with a rate of 55.29% at pH 2. Kinetics are rapid and equilibrium is reached after 60 minutes. Experimental results indicate that a mass of 0.01 g removes 53.26% of the pesticide and that the adsorption capacity increases with the concentration of the pesticide. The study of isotherms showed that the Freundlich model better describes the process of adsorption of difenoconazole on the PET char. The adsorption of difenoconazole on the char is therefore physical type. It is dominated by π-π, dipole-dipole and H bond interactions.