(715b) Optimization of Fenton's Oxidation Conditions for Removal of Chrysene in Aqueous Solutions

Polycyclic aromatic hydrocarbons (PAHs) are considered as environmentally hazardous organic contaminants and their carcinogenic nature and adverse ecological impacts prompted scientist to address ways to remediate these compounds from the contaminated environment. Among the PAHs, chrysene and its analogs are reported to be one of the potential groups of carcinogenic and mutagenic compounds. Fenton’s oxidation is one well known approach that has been used to remediate contaminated soils and water with PAHs. However, chrysene degradation in aqueous solution using Fenton’s oxidation has not been reported in the literature. The current work aims to optimize Fenton’s oxidation conditions for chrysene removal in aqueous solutions using batch tests. The effects of ferrous iron (3, 4, 5 and 6 mg/L) and H₂O₂ concentrations (10, 20, 40, and 80 mg/L) were tested on chrysene (1, 10 and 50 μg/L) degradation at room temperature with pH 3.5. To analyze chrysene concentration in Fenton’s oxidation post reaction samples, aliquots of samples were extracted using dichloromethane at various time intervals; 0.5, 24, 48 and 72h. Chromatographic analysis of chrysene concentration was achieved on a Waters LC/UV system equipped with a UPLC column and a UV detector using a gradient binary mobile phase at 268 nm.  Maximum degradation (50-51%) for 1 µg/L chrysene was observed when tested with 4mg/L of iron and 10/20 mg/L of H₂O₂ after 72h. Whereas, chrysene tested at 10 µg/L resulted 96-98% degradation with 5 mg/L of iron and 20/40/80 mg/L of H₂O₂ in 48h. Further, chrysene concentration was increased to 50 µg/L and tested against 5 mg/L of iron and 20/40/80 mg/L of H₂O₂ and the degradation rate monitored was 45-49% after 72h. Further experiments are in progress to optimize Fenton's reagent, pH and temperature conditions for maximum degradation of chrysene at various concentrations.