Study on humic acid adsorption by activated carbon powder

The adsorption study deals with the adsorption isotherms obtained from solutions of aldrich humic acid(AHA) with initial carbon concentration between 2.2 and 2.5 mg /L.For each experiment,a wide range of masses of activated carbon was selected(1~400 mg/L).By the application of several models of isothermal equilibrium,it appeared two straight lines of different slopes.The two lines are probably correspond,on one hand,to the adsorption of humic acids with the highest affinity,and on the other hand,to the adsorption of humic or fulvic acids with weaker adsorption capacity.The former organic fraction is one that is actually competing during adsorption of micropollutants.Great attention should be paid on these fractions when using adsorption treatment to control pesticide residues.