PEROXY-ACID TREATMENT OF POLYCYCLIC AROMATIC HYDROCARBONS IN LAKE SEDIMENTS

摘要

This study examines the degradation of polycyclic aromatic hydrocarbons (PAHs), such as a-methyl-naphthalene and benzo[a]pyrene, in lake sediments using an advanced oxidation process (AOP) employing peroxy acids as oxidizing agents. PAHs are organic compounds comprised of two or more fused aromatic rings. PAHs have earned U.S. EPA priority pollutant status, due to their genotoxic and hazardous properties. These compounds are hydrophobic, lipophilic, and relatively non-volatile causing sediment (and soil) contamination. Peroxy-acids are formed by the reaction between organic acids (e.g., acetic or propionic) and hydrogen peroxide. Laboratory experiments were conducted to study the abiotic degradation of PAHs in lake sediments. The sediments used in this study were collected from Lake Macatawa (Holland, MI) and ranged in total organic carbon (OC) content from 2.1% (sandy sediment samples) to 12.8% (silty-clay sediment samples). Lake sediments were also characterized using surface area ranging from 1.21 m~2/g (sandy sediment samples) to 21.95 m~2/g (silty-clay sediment samples). Analysis of the results demonstrated varied rates of degradation, depending on the type of acid and the characteristics of the sediment sample. Within 24 hours, a-methyl-naphthalene was reduced 70-100% of its original concentration. Benzo[a]pyrene was reduced by 80-100% of its original concentration when the AOP was used. Faster degradation was observed in silty-clay sediment samples, as well as with acetic acid. This method of PAH degradation is fast acting, relatively low-cost, and could be employed as an in-situ technology.