Two activated C were produced by carbonization of low quality hay and sawdust from coniferous wood in a microwave oven under CO2 at 800 degrees C, 1400 W, and 2.45 GHz studied for elementary compn., textural parameters and acid base properties and then used for removal of methylene blue, methyl red and Kongo red dies from their aq. solns. (concns. 10-60 mg/L). The adsorption efficiency was described by Langmuir and Freundlich isotherms. The activated C produced by microwave heating were only in some cases more effective adsorbents than those produced under conventional heating.