Coffee grounds were carbonized at 600 degrees C for 1.5 h, and activated by treatment with NaOH or H3PO4 at 500 degrees C for 1 h. The activated C samples were studied for their structure and sorption capacity by using methylene blue, p-nitroaniline and iodine. The C samples activated with H3PO4 showed a higher sorption capacity than those activated with NaOH. Adsorption isotherms were calculated.