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DESTRUCTION OF PAHS AND PCBS IN WATER USING SULFATE RADICAL-BASED CATALYTIC ADVANCED OXIDATION PROCESSES
Citation:
RASTOGI, S., S. R. AL-ABED, AND D. D. DIONYSIOU. DESTRUCTION OF PAHS AND PCBS IN WATER USING SULFATE RADICAL-BASED CATALYTIC ADVANCED OXIDATION PROCESSES. Presented at 1st European Conference on Environmental Applications of Advanced Oxidation Processes (EAAOP), Chania, GREECE, September 07 - 09, 2006.
Impact/Purpose:
To inform the public.
Description:
A new class of advanced oxidation processes (AOPs) based on sulfate radicals is being tested for the degradation of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in aqueous solution. These AOPs are based on the generation of sulfate radicals through Fe2+ mediated activation of peroxymonosulfate (KHSOs, PMS) or persulfate (Na2S208, PS). The high oxidation efficiencies of the free radicals (S04-0), in combination with the slow rate of consumption of the oxidants, make these processes very effective for the degradation of recalcitrant organic compounds like PAHs and PCBs. Degradation of naphthalene (a polycyclic aromatic hydrocarbon) and 2chlorobiphenyl (a polychlorinated biphenyl) in water is being studied using Fe2+/PMS and Fe2+/pS AOPs. Nearly complete removal of naphthalene and 2-chlorobiphenyl was observed when Fe2+ was used with PMS or PS. Adverse effect on the degradation efficiency was noted at elevated concentrations of Fe2+. At high concentrations, Fe2+ acts as radical scavenger for sulfate radicals and reduces the degradation efficiency. Optimum molar ratios of Fe2+ and oxidants were determined for the degradation of naphthalene and 2-chlorobiphenyl and found to be 1:1 molar ratios of Fe2+ and oxidant for both the contaminants. The impact of pH and buffering species (carbonate, phosphate) on the degradation efficiency of naphthalene and 2-chlorobiphenyl will also be presented.