Green synthesized iron nanoparticles as highly efficient fenton-like catalyst for degradation of dyes

Iron nanoparticles (Fe NPs) were synthesized herein through a simple and eco-friendly method using FeCl₃ and aqueous plant extract (dimocarpus longan, DL). Compared with Fe NPs prepared via traditional chemical methods, this biogenetic DL-Fe NPs demonstrates higher catalytic activity in Fenton-like reaction to degrade methyl orange (MO) in a wide pH range. It's worth noting that the DL-Fe NPs manifest a superior stability even after storage for at least 28 days. Systematic characterizations indicate that the active biomolecules from plant extract significantly contribute to the superior performance of DL-Fe NPs, by facilitating the dye molecules to be adsorbed on the surfaces of DL-Fe NPs, and providing a stable acid environment for the Fenton-like catalytic reaction. The kinetics study demonstrates this removal process conforms to the pseudo first-order model with the reaction activation energy of 41.6 kJ/mol. Moreover, various typical dyes including congo red, malachite green, methylene blue, eosin-Y and rhodamine B can be dramatically degraded by this DL-Fe NPs with a satisfactory removal efficiency.