Removal and destruction of organic compounds in water using adsorption, steam regeneration, and photocatalytic oxidation processes

A treatment strategy is examined whereby organic compounds in the aqueous p hase are first removed by fixed-bed adsorption, followed by off-line regene ration of spent adsorbent using saturated steam (160 degrees C) and cleanup of steam condensate using Fixed-bed photocatalysis. This treatment strateg y is examined with the following organic compounds: Tetrachloroethylene (PC E), carbon tetrachloride (CCl4), p-dichlorobenzene (p-DCB), o-chlorobipheny l (o-PCB), and methyl ethyl ketone (MEK). For six cycles of adsorption and regeneration, the steaming process is effective to regenerate the adsorbent exhausted with PCE, B-DCB, CCl4, or MEK. In the case of o-PCB, there is ab out 20% loss in adsorbent capacity after the first cycle, however, the adso rption capacity for Cycles 2-6 is almost the same. Fixed-bed photocatalysis is examined for decontamination of steam condensate carrying the desorbed organics, and it is observed to be effective for mineralization of aqueous phase PCE, p-DCB, CCl4, and o-PCB. In the case of MEK, although 97% of the compound was removed, only 16% removal of total organic carbon was observed , thereby suggesting that some by-products were produced that were refracto ry to oxidation.