Pre-adsorption and Fenton-like oxidation of mitoxantrone using hybrid green synthesized rGO/Fe nanoparticles

Emerging contaminants such as Mitoxantrone (MTX) are a major environmental concern because they have potential genotoxicity and mutagenesis to both aquatic organisms and humans. In this study, a pre-adsorption/Fenton-like oxidation system was developed which used a reduced graphene oxide/iron nanoparticles hybrid (rGO/Fe NPs) as both the adsorbent and the Fenton catalyst to remove MTX from solution. While the addition of H 2 O 2 alone removed only 11.3% of MTX, the rGO/Fe NPs/H 2 O 2 system was significantly more efficient removing 99.8% of MTX in the same period. This indicated that rGO/Fe NPs had excellent catalytic activity even at pH 7. This efficient removal was attributed to significant production of ·OH mainly by heterogeneous catalysis but supplemented by a homogeneous Fenton reaction, where ·OH had a higher affinity for MTX than SO 4 − ·. The sequential Fenton-like oxidation process best fits a pseudo-second-order kinetic model (R 2  ≥ 0.974). Characterizations of rGO/Fe NPs before and after the reaction, together with the identification of specific MTX degradation products , allowed possible degradation pathways to be proposed together with insights into the underlying mechanisms of MTX degradation when using rGO/Fe NPs in a pre-adsorption/Fenton-like oxidation system. Finally, the rGO/Fe NPs developed was successfully applied for the removal of MTX from spiked wastewater with 93.6% removal efficiency, which indicated that the proposed system had significant potential for wastewater treatment applications.