Treatment of contaminated water with pesticides via adsorption

Static adsorption experiments of pesticides (alachlor, trifluralin and prometryn) on amberlite XAD-4 were carried out at pH 5. The effect of ionic strength (0.01-2 M) on the pesticides adsorption was also investigated. This effect is more pronounced for the adsorption of more polar molecules (alachlor and prometryn) compared to trifluralin adsorption. This phenomenon can be attributed to the enhancement of the polar interactions in combination with the salting out effect. Adsorption increase reached 373% for alachlor, 295% for prometryn and 234% for trifluralin. The estimated heat of adsorption (- 9.8 to -23.8 kcalmol(-1)) based on the experimental data indicate that chemical adsorption as well as physical adsorption may occur.