Corncob,which is the main waste from corn a gricultures in Egypt,has been used as a raw material for the preparation of different activated carbons.Activated carbons(ACs) were prepared by chemical activation with concentrated H3PO4 acid;followed by pyrolysis at 400, 500 and 600C. Different ACs have been used for the removal of methyleneblue(MB) dye from aqueous solutions. Batch adsorption experiments were performed as a function of initial dye concentration, contact time, adsorbent dose and pH. Adsorption data were modele dusing the Langmuir and Freundlich adsorption isotherms.Adsorption of MBonAC1(R2¼0.9868) andAC2(R2¼0.9810) followed Langmuir model with maximum
monolayer sorption capacity of 28.65 and 17.57mg/g, respectively. Adsorption onto AC3 was better fitted to Freund lichisotherm
model (R2¼0.9823).