Abstract
This study focused on the degradation of the emerging contaminant naproxen in aqueous solutions by gamma irradiation. Influence of initial naproxen concentration, solution pH, various additives (CH3OH, H2O2,
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, and humic acid), and absorbed dose on naproxen degradation were investigated. At a naproxen concentration of 23.6 mg/L and an absorbed dose of 1.0 kGy, the extent of naproxen degradation was 98%. The degradation reaction of naproxen followed first-order like kinetics. Addition of 40 mg/L humic acid or 0.5% H2O2 enhanced the naproxen degradation, whereas 1.5% CH3OH and 1.5% H2O2 inhibited naproxen degradation. Added
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slightly decreased naproxen degradation. The naproxen degradation efficiency was higher under acidic conditions than in neutral or alkaline media. The solution pH value became lower as the absorbed dose increased. Identification of byproducts revealed that decarboxylation is the principal initial process in the degradation of naproxen under the conditions used in these experiments.
