Efficient Remediation of -chloroaniline Contaminated Soil by Activated Persulfate Using Ball Milling Nanosized Zero Valent Iron/Biochar Composite: Performance and Mechanisms.

In this study, efficient remediation of -chloroaniline (PCA)-contaminated soil by activated persulfate (PS) using nanosized zero-valent iron/biochar (B-nZVI/BC) through the ball milling method was conducted. Under the conditions of 4.8 g kg B-nZVI/BC and 42.0 mmol L PS with pH 7.49, the concentration of PCA in soil was dramatically decreased from 3.64 mg kg to 1.33 mg kg, which was much lower than the remediation target value of 1.96 mg kg. Further increasing B-nZVI/BC dosage and PS concentration to 14.4 g kg and 126.0 mmol L, the concentration of PCA was as low as 0.15 mg kg, corresponding to a degradation efficiency of 95.9%. Electron paramagnetic resonance (EPR) signals indicated SO•, •OH, and O• radicals were generated and accounted for PCA degradation with the effect of low-valence iron and through the electron transfer process of the hybridized carbon structure of biochar. 1-chlorobutane and glycine were formed and subsequently decomposed into butanol, butyric acid, ethylene glycol, and glycolic acid, and the degradation pathway of PCA in the B-nZVI/BC-PS system was proposed accordingly. The findings provide a significant implication for cost-effective and environmentally friendly remediation of PCA-contaminated soil using a facile ball milling preparation of B-nZVI/BC and PS.