Activation of Peroxymonosulfate by Fe0 for the Degradation of BTEX: Effects of Aging Time and Interfering Ions

Abstract

Resolving three environmental challenges simultaneously—recycling bone waste, aggregation, oxidation of bare nZVI and benzene, toluene, ethylbenzene, and p-xylene (BTEX) contamination—was conducted by fabricating a highly stable and efficient activator of peroxymonosulfate. In this work, a novel heterogeneous catalyst, ostrich bone ash-supported nanoscale zero-valent iron (Fe0-OBA) prepared by pyrolysis of animal bones and reduced Fe2+ on the surface of it, was used for the activation of peroxymonosulfate (PMS). Advantageous properties such as extensive availability, low production cost, and high thermal stability make OBA an appealing carbonaceous material for heterogeneous catalysis. The TEM and SEM results revealed that the black ball-shaped nZVI particles were uniformly dispersed on the surface of OBA. The Fe0-OBA composite had a porous structure with a specific surface area of 109 m2 g−1 according to BET analysis. With BTEX as the refractory pollutant, the PMS-based Fe0-OBA system shows great degradation performance as compared to the homogeneous Fe2+/PMS system. The effects of various parameters, such as initial pH (2–9), temperature (25–45 °C), initial BTEX concentration (50–200 mg L−1), PMS dosage (0.5–1.25 mM), time of reaction (0–60 min), and Fe0-OBA dosage (0.5–5 g L−1) on the BTEX degradation, have been discussed in detail. The pseudo-first-order kinetic model can describe the BTEX degradation by the PMS-based Fe0-OBA system. The excellent stability of Fe0-OBA even after 10 years, while maintaining the degradation efficiency, shows the high potential of it in a wide range of practical applications. This study illustrated that Fe0-OBA could be an effective activator of PMS for the degradation of stubborn organic contaminants in water and wastewater.