For the chemical activation, the pre-treated cork (particle size between 0.5 and 1.0 mm) was impregnated in solution with the activating agent in a weight proportion cork:activating agent of 1:1 and 1:2, during 2 h for KOH (Panreac, 85%),and 24 h for
K2CO3 (Aldrich, 99%), at room temperature. After drying, the mixtures were activated at 700 and 800 C in a horizontal furnace (Thermolyne, model 21100) during 1 h under N2 flow of 5 cm3 s1 (heating rate of 10 C min 1).