The production of attrition resistant, sewage-sludge derived, granular activated carbon

Granular activated carbon (GAC) production from waste materials is of considerable interest. However, waste-derived GACs may exhibit an inferior attrition resistance, inhibiting their use in pressure swing adsorption (PSA) processes or adsorption beds. This study investigated the use of pelletisation to improve the attrition resistance of a sewage sludge-derived GAC. Both extrusion and hydraulic compaction were investigated as pellet production techniques. A range of binders were evaluated, as follows: Ammonium LignoSulphonAte (ALSA); PolyVinyl Alcohol (PVA); phenolic resin; araldite resin; LignoSulphonic Acid, Calcium salt (LSAC); CarboxyMethyl Cellulose sodium salt (CMC). Hydraulic compaction (typically >500 kg/cm(2)) was found to be more effective than extrusion. Both low (40-110 degrees C) and high (500-800 degrees C) curing temperatures were assessed, as was the sequencing of the steam activation and pelletisation steps. The most effective pellet production method comprised coupling a lignosulphonate binder with post-pelletisation activation. (C) 2012 Elsevier B.V. All rights reserved.