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

Abstract

In this study, efficient remediation of p-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−1 B-nZVI/BC and 42.0 mmol L−1 PS with pH 7.49, the concentration of PCA in soil was dramatically decreased from 3.64 mg kg−1 to 1.33 mg kg−1, which was much lower than the remediation target value of 1.96 mg kg−1. Further increasing B-nZVI/BC dosage and PS concentration to 14.4 g kg−1 and 126.0 mmol L−1, the concentration of PCA was as low as 0.15 mg kg−1, corresponding to a degradation efficiency of 95.9%. Electron paramagnetic resonance (EPR) signals indicated SO4•−, •OH, and O2•− radicals were generated and accounted for PCA degradation with the effect of low-valence iron and through the electron transfer process of the sp2 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.

Recent Advances in Nanoscale Zero-Valent Iron (nZVI)-Based Advanced Oxidation Processes (AOPs): Applications, Mechanisms, and Future Prospects

“…In the past few decades, the anthropogenic pollution of water bodies has become one of the most problematic crises facing the world [1][2][3]. Large quantities of pollutants, such as dyes, antibiotics, pesticides, chlorinated organics, polycyclic aromatic hydrocarbons, and personal care products, have been discharged into water, posing severe threats to ecosystems and human beings [4][5][6]. Therefore, the development of an efficient, ecofriendly, and cost-effective approach for the removal of industrial and municipal water pollutants, which have attracted extensive attention, is of utmost importance [7][8][9].…”