Abstract: The remediation of polycyclic aromatic hydrocarbons (PAHs) in soil and groundwater environment has become an important environmental problem in the world. In order to solve the problem of low degradation efficiency of Fe-based activated materials during chemical degradation, nano-zero-valent iron (nZVI) and sulphur-modified nano-zero-valent iron (S-nZVI) were prepared by liquid-phase reduction method, and the phenanthrene degradation process was optimized by degradation kinetics, activation material characterization and oxidant ratio test. The results showed that S-nZVI had the highest activity when the molar ratio of S/Fe was 0.28, and the degradation rate of phenanthrene was 88.44% at 90 min. The order of activation effect from high to low was S-nZVI > nZVI > Fe²⁺> no activator. The results of energy spectrum analysis showed that the reference S/Fe molar ratio of S-nZVI nano-activated material was 0.08. When the molar ratio of persulfate/S-nZVI was 200, the activated degradation efficiency was still high.

Key words: sulfur-modifying, nano zero-valent iron, sodium persulfate, phenanthrene, chemical degradation