AbstractThe waste of medium density fiberboards was carbonized at a temperature of 500 °C. The activated carbons were obtained after 16 h of impregnation and 1 h of activation by KOH at 800 °C with KOH/coke mass ratios of 2.5, 3.0, 3.5, and 4.0. The activated carbons were investigated for determination of porosity and elemental analysis. The results showed that the surface area of the activated carbons varied from 1456 to 1647 m2/g and the total pore volume ranged from 0.701 to 1.106 cm3/g, which was affected by different KOH/coke mass ratios . The pore size distribution indicated that waste medium density fiberboard activated carbons included both micropores and mesopores, and the elemental analysis implied that the contents of nitrogen varied from 0.97% to 2.60%. Electric double layer capacitors were made using the activated carbons and their electrochemical properties were studied. The specific capacitances of the activated carbon electrodes ranged from 212 to 223 F/g. The results suggest that activated carbon from waste medium density fiberboard can be a candidate material for electric double layer capacitor electrodes because of its good electrochemical capacities.