Green synthesis of Fe2O3-Ag nanocomposite using Psidium guajava leaf extract: An eco-friendly and recyclable adsorbent for remediation of Cr(VI) from aqueous media.

An environmental friendly and cost effective method was used for the preparation of silver‑iron oxide (α-Fe2O3-Ag) nanocomposite using guava (Psidium guajava) leaf extract, which can be used as an adsorbent for decontamination of chromium (VI) ions from aqueous media. XRD analysis revealed that both Iron oxide and silver nanoparticles are crystalline in nature with face-centered cubic and rhombohedral geometry respectively. The FESEM micrographs of Fe2O3-Ag nanocomposite displayed irregular shaped particles with an average size of 50-90 nm. BET surface area analysis suggests that the prepared Fe2O3-Ag nanocomposites are mesoporous in nature with surface area of 122.72 m2/g. The adsorption of Cr(VI) was pH dependent and maximum adsorption occurred at pH = 4 with maximum adsorption capacity of 71.34 mg/g. Thermodynamic parameters reveals that the Cr(VI) adsorption on Fe2O3-Ag surface is endothermic and spontaneous in nature. The adsorbed Cr(VI) on Fe2O3-Ag surface was recovered and can be reused up to five cycles.