Zero-valent iron (ZVI) Activation of Persulfate (PS) for Degradation of Para-Chloronitrobenzene in Soil

Para-chloronitrobenzene (p-CNB) in soil has posed significant health risks because of its persistence and high toxicity. The efficacy of catalyzed Zero-Valent Iron (ZVI), activated persulfate, and ZVI-persulfate processes for the degradation of p-CNB in soil was investigated. The p-CNB removal rate significantly increased from 10.8 to 90.1% with increased ZVI dosage from 0.1 mmol g⁻¹ to 1.0 mmol g⁻¹. The p-CNB removal increased with the decrease of initial pH and a removal efficiency of 85.3% was obtained at an initial pH value of 6.8 in combined system. The p-CNB removal rate in the single persulfate system and ZVI system was 36.5% and 60.2%, while the ZVI-persulfate system showed more sufficient p-CNB removal capacity and the removal rate of p-CNB was 88.7%. Scanning electron microscopy (SEM) and Electron paramagnetic resonance (EPR) was adopted in order to explore the degradation mechanism by ZVI-Persulfate system in soil.