Optimization of the peroxy acid treatment of alpha-methylnaphthalene and benzo[a]pyrene in sandy and silty-clay sediments.

The majority of polycyclic aromatic hydrocarbons (PAHs) released to the environment come from anthropogenic sources involving the incomplete combustion of organic compounds. Several techniques are available for the degradation of PAHs. Among the abiotic/biotic processes used to degrade PAHs, an alternative strategy utilizing a primary chemical oxidative step to be combined with a biological was created. The degradation of alpha-methylnaphthalene and benzo[a]pyrene using an advanced oxidation process was optimized over a period of 24 h by varying the ratio of acetic acid to hydrogen peroxide, the compounds that form peroxy acids. The optimization process was performed using sandy and silty-clay sediment types. Gas chromatography equipped with a flame ionization detector was used to determine the varied rates of degradation depending on acetic acid:hydrogen peroxide ratios and the characteristics of the sediment sample. Reduction of 20-90% of alpha-methylnaphthalene and benzo[a]pyrene was observed when 2-5 mL of hydrogen peroxide was used, respectively. A peracetic acid solution (e.g., a commercial form of acetic acid and hydrogen peroxide) was used to compare the results from the peroxy acid experiments. In all the experiments, peracetic acid was more reactive than the combination of acetic acid and hydrogen peroxide. Acetic acid, deionized water, and hydrogen peroxide served as controls and demonstrated minimal degradation over the time course study. Therefore, the use of a peroxy acid process to target electron dense pollutants may have a great utility.