Production of activated carbons from wheat using phosphoric acid activation

The production of activated carbons from wheat via phosphoric acid activati on has been studied by means of two processes, i.e., the one-stage and two- stage processes. The former comprises simultaneous carbonization and activa tion after impregnation; the latter, the carbonization of the precursor at 300 degrees C for 10 minutes, followed by the activation of the resultant c har impregnated with phosphoric acid. The preparation conditions, e.g., pho sphoric acid concentration and activation temperature, have been varied to determine the optimal processing conditions; activation duration was fixed at 15 minutes for both processes. The optimal activation conditions for the highest BET surface areas have be en determined to be 700 degrees C with an acid concentration of 35% for the one-stage process and 600 degrees C with an acid concentration of 50% for the two-stage process. The two-stage process has been found to greatly enha nce the porosity development, especially the microporosity.