ABATEMENT OF POLLUTANTS BY ADSORPTION AND OXIDATIVE CATALYTIC REGENERATION

The adsorption of phenol, and halogenated phenols on granular activate d carbon (AC) modified with metal oxide catalyst, followed by catalyti c oxidative regeneration, was studied as an efficient technology for t he treatment of dilute wastewaters. The advantages of the combination of these technologies are as follows: (1) the process will be accelera ted by the high concentrations of pollutants eluted from the adsorbent ; (2) a large number of adsorption-regeneration cycles are expected wi thout loss in capacity; and (3) the low-temperature regeneration will be conducted in situ, even in small units, thus improving the economy of the process. Oxidative catalytic regeneration of spent carbons, per formed at 240-300 degrees C with air, completely restored the adsorpti on capacity of phenol on the ACs modified with catalyst, even after 10 cycles of regeneration. Under similar conditions, only partial recove ry of the adsorption capacity was obtained for carbons loaded with p-c hlorophenol and p-bromophenol. The adsorption capacity and the surface area of the AC (Filtrasorb-400) diminished somewhat with the impregna tion of oxides (Fe2O3, CuO, and additivities of Cr2O3 or inert silica) , but that did not affect the shape of the adsorption isotherms.