Thermal regeneration of a spent activated carbon previously used as hydrogen sulfide adsorbent

The feasibility of thermal regeneration of spent coconut shell-based activated carbon previously used as hydrogen sulfide adsorbent was studied in three successive adsorption/thermal regeneration cycles. The regeneration of exhausted carbon was done by heating the samples at 300 degreesC. The observed changes in the capacity were linked to changes in surface chemistry and porosity. Heating in air atmosphere resulted in the removal of sulfur dioxide and oxidation of elemental sulfur to sulfur oxides. All sulfur from small pores was removed and the pore structure was 100% regenerated. Good agreement in the balance of sulfur species removed from the carbon surface shows that during the treatment all desorbed gases can be collected minimizing the environmental hazard. The results show that the capacity of the carbons to adsorb hydrogen sulfide can be regenerated to at least 30% of its initial value. (C) 2001 Elsevier Science Ltd. AII rights reserved.