Green synthesis, characterization of biomaterial-supported zero-valent iron nanoparticles for contaminated water treatment

Background: In this present work, we synthesized zero-valent iron nanoparticles (ZVIN) using reproducible Calotropis gigantea (CG) flower extract served as both reducing and stabilizing agent by completely green approach. ZVIN are widely used in contaminated water treatment and can be prepared by several different methods. Method: Iron nanoparticles formed in this method are mainly ZVIN and were characterized by the various physicochemical techniques, viz, ultraviolet-visible absorption spectroscopy (UV-vis), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Results: FT-IR and UV-vis absorption spectra reveal that the polyphenols present in the CG flower extract may be responsible for the reduction and stabilization of the ZVIN. SEM images show some agglomeration among the particles and the average size of the particles in the range of 50–90 nm. ZVIN tend to agglomerate, resulting in a significant loss of reactivity. To overcome this problem, we have synthesized ZVIN that are immobilized on biomaterial with the help of chitosan. This low-cost sorbent was used to remove organic pollutants from waste water. Conclusions: Herein, we report the percentage of removal of methylene blue (MB) and aniline by synthesized sorbent from contaminated water. The adsorption isotherms of Langmuir and Freundlich models have been used to explain experimental equilibrium adsorption data. The adsorption of MB and aniline on sorbent follows pseudo-second order kinetics.