Lignocellulosic agricultural residues are worldwide used for the production of activated carbons with purpose of eliminate a large range of pollutants such as diuron, a very per- sistent herbicide found in streams. This work studies the adsorption of diuron in aqueous solution on two different activated carbons, a commercial activated carbon and a prepared one. Activated carbon has been produced from seed hulls of baobab (Andansonia digitata), as a valorization pathway for this waste. Precursors have been impregnated with potas- sium hydroxide and then carbonized under nitrogen flow. The porous structure of the carbon has been determined by methylen blue adsorption, iodine adsorption and nitro- gen adsorption-desorption. The BET surface areas of the produced carbon was 1086 m2·g–1 with an iodine and methylene blue values of 1854.2 mg·g−1 and 26.66 mg·g−1 respectively. Batch removal kinetics of diuron has been studied at 5, 13 and 20 ppm initial concentra- tions on the two activated carbons in a reconstituate solution. The results showed that adsorption of diuron can be modelled by Langmuir isotherm with a maximal adsorption capacity of 65.7 mg·g−1 for baobab carbon and 151.8 mg·g−1 for commercial activated car- bon at 120 min equilibrium time. Speudo-second order reaction fits well with data col- lected during adsorption of diuron on carbons studied. Thus, Baobab seed hulls can be considered as good precursors for preparation of activated carbon with high specific sur- face area.

Baobab seed hulls Activated carbon Porosity Adsorption