Fullerol mediated enhancement of chloramphenicol degradation in Fe(III)/H2O2 system by accelerating Fe(III)/Fe(II) cycle via a non-photochemical pathway

Abstract

Hydroxylated fullerene, Fullerol, has applied in many areas because of its high electron affinity and antioxidant potential, while it was few used in wastewater treatment. In this study, the mechanism involved that Fullerol accelerated the regeneration of Fe(II) in the Fe(III)/H2O2 system under dark condition, which was investigated with chloramphenicol (CAP) as a model pollutant. In Fullerol/Fe(III)/H2O2 system, CAP removal was completely achieved at 60 min via a non-photochemical pathway. In addition, the quenching experiments and electron spin resonance (ESR) results indicated that hydroxyl radical (OH) was the main reactive oxygen species (ROSs). The Fullerol/Fe(III)/H2O2 system had a rate constant of CAP degradation about 5.0 × 10−2 min−1, which was about 22 times higher than it in Fe(III)/H2O2 Fenton-like system (2.3 × 10−3 min−1). Fe(II) was ascertained the effective component that was responsible for H2O2 activation to produce OH, which derived from 1) the first pathway: Fullerol complexed with Fe(III) and the redox potential of the complex is much lower than Fe(III)/Fe(II); 2) the second pathway: Fullerol acted as an electron donor to reduce Fe(III) into Fe(II). Moreover, CAP degradation intermediates were identified and its degradation pathways were proposed. This study suggested a new approach for improving the Fe(III)/H2O2 system by accelerating Fe(III)/Fe(II) cycles with Fullerol.