Degradation of Pyrene Contaminated Soil with Spiked ¹⁴C Pyrene by Hemoglobin Catalysis

Hemoglobin (Hb) is a member of the hemeprotein family that undergoes non-specific catalytic chain reactions in the presence of hydrogen peroxide (H₂O₂). The catalytic ability of Hb to degrade the carcinogenic polycyclic aromatic hydrocarbon pyrene was demonstrated using soil contaminated with ¹⁴C pyrene. Three bench-scale laboratory tests were performed using ¹⁴C pyrene in the presence of a buffer, H₂O₂, and a combination of Hb and H₂O₂. The initial pyrene concentration of the contaminated soil was set to 11 mg/kg, with 5,500,000 dpm of ¹⁴C pyrene. After a catalytic reaction for 24 h, the results showed that 17% of pyrene was degraded by H₂O₂, 38% of pyrene was degraded by Hb in combination with H₂O₂, and 0.13 and 1.2% of ¹⁴C pyrene were mineralized by H₂O₂ and Hb in combination with H₂O₂, respectively. An analysis of the products from the reaction involving Hb in combination with H₂O₂ revealed that 15.9% of the ¹⁴C intermediates in the acetonitrile fraction were polar products. After the catalytic reaction, 21 intermediate compounds were found via fraction analysis. The results suggested that Hb catalysis could be used to treat pyrene-contaminated soil as a novel catalytic technology for the remediation of hazardous materials in soil.