Degradation Prediction and Products of Polycyclic Aromatic Hydrocarbons in Soils by Highly Active Bimetals/AC-Activated Persulfate

In this study, activated carbon (AC)-supported bimetallic materials (Fe-Ni/AC) were synthesized to activate persulfate for the degradation of 19 types of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil. Fe-Ni/AC-activated persulfate exhibited a higher PAH removal efficiency in the soil remediation process compared to unactivated persulfate. After a 72 h treatment at 50 degrees C, the degradation efficiency for total PAHs was similar to 86%. Based on this result, an innovative deep learning neural network model for predicting PAH degradation efficiency was developed. The correlation coefficients between the predicted and actual values were 0.5403 (21.5 degrees C) and 0.6125 (50 degrees C), indicating significant correlation. The degradation products of 2-6-ring PAHs could be divided into oxy-PAHs, ketones-PAHs, methyl phenols, and non-PAHs, among which monocyclic non-PAHs were the main degradation products. In addition, signals indicating unexpected intermediate products of PAHs such as environmentally persistent free radicals (EPFRs) were detected from the PAH-contaminated soil samples at different reaction times. The PAH-type radical with a g-factor of 2.0019 and oxygenic carbon-centered radicals with a g-factor of 2.0036 were identified. This study shows that Fe-Ni/AC-activated persulfate is efficient for PAH removal and thus is suitable for the remediation of PAH-contaminated soils.