The influence of the impregnation method on yield of activated carbon produced by H3PO4 activation

The influence of the impregnation method on producing activated carbon (AC) from cherry stones (CS) using H3PO4 is studied. Mass changes associated with the impregnation, carbonization and washing processes were measured. With H3PO4 dilute solutions, the loading of substance on CS increases with concentration, in particular when the impregnation is effected in a single step instead of in successive steps and especially when using CS chars. The opposite applies when filtering the residual liquid and washing the resulting product. With the concentrated solution, regardless of whether it is previously oven-drying at 120 degrees C or not, most H3PO4 is loaded on CS. The concentration of the H3PO4 solution seems to control the processes of impregnation, carbonization and washing in the preparation of AC from CS by H3PO4 chemical activation. (C) 2011 Elsevier B.V. All rights reserved.