Using the radiolabeled model pollutants 2,4-dichlorophenol (DCP) and 2,4,5-trichlorophenol (TCP) we demonstrated that brief UV (300-nm) photolysis greatly facilitates the removal of the two chlorophenols from sewage through accelerated mineralization and binding of polar products. The addition of 0.1 M H2O2 strongly accelerated the photolysis process resulting in half-lives of 1.68 and 0.87 min for DCP and TCP, respectively. In natural sunlight, half-lives of the chlorophenols were less than 1 day when H2O2 was present. During 4 days of incubation in activated sewage sludge, only 3% of unphotolyzed DCP and 1 % of unphotolyzed TCP were mineralized. Mineralization rose to79 and 59%, respectively, after photolysis in the presence of H2O2. Photolysis without H2O2 resulted in removal ofchlorophenols from solution chiefly by binding. Increased mineralization and binding were observed also upon incubationof photolyzed chlorophenols in soil. Disruption of carbon-halogen bonds by brief photolysis followed by traditional biological effluent treatment offers an alternative to activated charcoal treatmentfor removal of xenobiotics from industrial effluents.
ASJC Scopus subject areas
- Environmental Chemistry