Wood-based activated carbons as adsorbents of hydrogen sulfide: A study of adsorption and water regeneration processes

Wood-based carbon was studied as a hydrogen sulfide adsorbent in three adsorption/regeneration cycles. The regeneration was done using a constant amount of either hot or cold water. The performance of carbon and efficiency of its regeneration were evaluated on the basis of the amount of hydrogen sulfide adsorbed and on the selectivity of the carbon surface for oxidation of H2S to sulfur oxides. The latter, as the products of surface reactions, made the regeneration feasible. To check the effect of aging/surface oxidation the tests were carried out on fresh and 3-year-stored carbon samples. The results obtained showed that the surface of fresh carbon can be regenerated to some extent, whereas in the case-of aged materials the water regeneration is inefficient due to the deposition bulky sulfur polymers resistant to oxidation at temperatures up to 100 degrees C. Both hot and cold water treatment results in similar degree of regeneration of the carbon surface.