The Speed of Attainment of Sorption Equilibria in Some Systems Involving Herbicides

Summary. Measurements were made of the time taken for equilibrium to be established during adsorption and desorption under aqueous slurry conditions using monuron, linuron, atrazine and chlorpropham with a variety of adsorbents. An appreciable time was taken for equilibria to be established in adsorption processes, although with one exception, this period was 24 hr or less. Desorption processes were generally rather slower and in seven cases out of eighteen equilibrium was apparently not established in 72 hr. However, in all but two cases it seemed likely that the sorption process was reversible or nearly so. Possible explanations for differences of equilibrium times are discussed together with implications the results might have on the interpretation of leaching phenomena. Vitesse à laquelle est atteint I'équilibre d'adsorption et de désorption dans certains systèmes impliquant des herbicides