Cyclic adsorption/thermal regeneration of activated carbons

In this work, the cyclic thermal regeneration of activated carbons saturated with p-Nitrophenol was analyzed with two complementary views: the examination of the process itself and the porosity modifications found in the adsorbents. The process, which was followed by TG/DTG/TDA analysis, showed that the regeneration process is highly dependent on the number of uses of the carbon. As it is reused, it becomes more and more resistant towards the heat treatment. Regarding the porosity, the fresh adsorbent (V-mi = 0.42 cm(3) g(-1)), underwent a significant porosity decrease after saturation (V-mi = 0.04 cm(3) g(-1)), mainly due to micropore blockage. The subsequent regeneration succeeded to render around 70% of the adsorbent N-2 uptake. However, further uses of the carbon resulted in a progressive decay of the adsorbent capacity, with a marked porosity widening. These features were further investigated by means of Scanning Electron Microscopy and Infrared Spectroscopy. (C) 2014 Elsevier B.V. All rights reserved.