Green synthesis of highly stable zero-valent iron nanoparticles for organic dye treatment using Cleistocalyx operculatus leaf extract

Abstract

Zero-valent iron nanoparticles are considered promising nanomaterials for wastewater treatment. However, the use of highly toxic and expensive chemicals such as sodium borohydride during synthesis has significantly limited the broad application of zero-valent iron. In this study, zero-valent iron nanoparticles (nZVI) were facilely and friendly synthesized using Cleistocalyx operculatus leaf extract as a reducing agent. The morphology and structure of the as-prepared nanomaterials were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analysis. The obtained product was spherical with an average diameter of approximately 100 nm. The prepared nZVI exhibited remarkably stable stability, which remained in the nZVI form for more than one month in open air. The removal efficiency of rhodamine B (RhB) by nZVI reached over 95% in 30 min, proving that the nZVI nanomaterials exhibited a high and quick degradation performance toward RhB. The RhB removal efficiency of nZVI, which was proportional to the amount of nZVI and influenced by pH conditions, was determined using the visible ultraviolet absorption spectroscopy.