| Abstract: | Surface oxygen has an important effect on the wet air regeneration (WAR) of powdered activated carbons (PAC) and on the adsorption properties of the regenerated PAC. Virgin and phenanthrene-loaded PACs were regenerated in a bench-scale reactor, and then analyzed to determine surface oxygen content, adsorption capacity, and extent of phenanthrene oxidation.Even though the virgin wood-base (WB) and lignite-base (LB) PACs had about the same oxygen content, the oxygen content of the WB PAC increased more than twice as much as the LB PAC during regeneration. The difference was caused by the larger amount of CO2-evolving oxides that formed on the WB PAC. WAR reduces the capacity of PAC for p-nitrophenol (PNP). Removing the surface oxides had varying effects on the carbon's capacity for PNP. Also, adsorbed phenanthrene was more easily oxidized on the WB PAC than on the LB PAC during regeneration. |
