Soil Decontamination by Natural Minerals Via Fenton-Like Reactions: A Comparison Study of Chalcopyrite and Pyrite

Organic pollution of soil has raised worldwide concern owing to the potential effects on ecosystems and human health. Natural minerals have the potential prospect to be developed into cost-effective and environmentally benign catalysts to decontaminate soil. Herein, a comparison study employing natural chalcopyrite (NCP) and natural pyrite (NP) as activators in the combined Fenton-like systems of peroxymonosulfate (PMS) and hydrogen peroxide (H2O2) to degrade organic pollutants in soil has been carried out. Tetracycline hydrochloride (TCH) and phenanthrene (PHE) were used as representatives of widely existed contaminants, antibiotics and polycyclic aromatic hydrocarbons in the study. It was demonstrated that both NCP and NP can effectively activate the combined PMS/H2O2 system, while NCP exhibited higher catalytic activity towards the degradation of both two kinds of pollutants in comparison with NP. The more superior performance of NCP has been elucidated via analysis and comparison of the catalytic mechanisms of NCP and NP. Key parameters in the degradation process including initial pH, catalyst and oxidants dosage were also optimized. A mineralization ratio of 93.04% was achieved for PHE after 24 h treatment in the NCP/PMS/H2O2 reaction system and the possible degradation pathway was proposed based on the main intermediates identified by GC-MS analysis. In addition, the results of radical quenching experiments indicated that the •OH prevailed over SO4•− in the PMS/H2O2 systems and •O2− also played a vital role in the process. We anticipate this study would provide implications for the utilization of natural minerals in the removal of refractory organic pollutants in soil.