Green synthesis of chitosan-based iron@silver nanocomposite as adsorbent for wastewater treatment

Abstract

Chitosan–iron@silver (CS–Fe@Ag) nanocomposite was synthesized by a simple green synthetic method. The bimetallic Fecore@Agshell nanoparticles (NPs) were synthesized through a simple reduction of equimolar amounts of their salt mixture with Alchornea laxiflora leaf extract at 100 °C. The resulting bimetallic nanoparticles and nanocomposite were characterized with Fourier transform infrared (FTIR) and UV–visible spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) techniques. The evidence for the formation of Fecore@Agshell NPs within the chitosan polymer matrix was confirmed by UV–visible, XRD and FTIR spectra where the bonding of the bimetallic shell (Agshell) with carboxyl group to form Ag–O was confirmed. The effect of dosage, pH and agitation time on turbidity reduction of wastewater was studied to determine optimum conditions for the determination of water quality parameters. The CS-Fe@Ag nanocomposite gave higher maximum removals of BOD (48.7%), COD (15.5%) and TDS (54.9%) than pure CS with BOD (25.5%), COD (3.6%) and TDS (38.9%) at optimum conditions.