In this study, the complex interaction of oxidizing conditions, soil composition, microbial activity, and phenanthrene (PHE) degradation was explored in persulfate (PS)-Pseudomonas aeruginosa GZ7 remediation of four PHE-contaminated soils: Paddy soil (PAS), Saline soil (SS), Red soil (RS), and Cinnamon soil (CS). Batch experiments displayed the optimal PS dosage was 0.750 % (w/w), except for CS (0.125 %), achieving PHE degradation rates of 54.79 similar to 81.92 % on the 27-day. The zeta potential of soil clay component after 0.750 % PS oxidation was lower than 0.125 % and 2.000 % PS, resulting in a higher PHE bioavailability and biodegradation. The electron paramagnetic resonance (EPR) spectroscopy analysis showed that the abundance of dominant hydroxyl radicals (center dot OH) in CS was 3 times higher than in PAS at 0.750 % PS and PS to Fe2+ molar ratio of 2:1, indicating that a higher soil organic matter would decrease the content of center dot OH thus diminishing PHE removal. Stepwise linear regression and sensitivity analysis indicated that the key influential factors in the PHE degradation rate were the residual PHE content after oxidation (60.12 %) and hydrolase nitrogen content (30.97 %). High-throughput sequencing results showed the bacterial diversity and richness in four soils decreased after combined remediation compared to pristine soil. Redundancy analyses revealed that the fluorescein diacetate (FDA) hydrolase enzyme was the key factor effect of soil bacterial community development in SS; the electrical conductivity and FDA hydrolase enzyme were the key factors in RS, CS, and PAS. This study may provide technical support for optimizing chemical conditions for PS-microbial remediation.
