Sustainable fabrication of hematite (α-Fe2O3) nanoparticles using biomolecules of Punica granatum seed extract for unconventional solar-light-driven photocatalytic remediation of organic dyes

Abstract

Seeking an effective strategy to develop inexpensive and highly stable photocatalyst materials for dye degradation is of great significance to resolve the global environmental problems caused by dye abuse. Herein, we have reported the environmental-friendly synthesis of exceptionally efficient and highly sustainable hematite nanoparticles (α-Fe2O3 NPs) using Punica granatum seed extract biomolecules. The morphology and phase purity of the synthesized α-Fe2O3 NPs were executed through a series of characterization techniques. FESEM and TEM analysis exhibited that the synthesized α-Fe2O3 NPs were irregular-shaped with an average size of 26.53 nm, while the BET surface area of nanoparticles was estimated to be 31.52 m2/g with an average pore diameter of 5.54 nm. α-Fe2O3 NPs exhibited typical ferromagnetic behavior at room temperature. The oxidation states of elements in α-Fe2O3 NPs were confirmed through X-ray photoelectron spectroscopy (XPS) analysis, while the charge on α-Fe2O3 NPs was found to be −10.6 mV. The as-prepared α-Fe2O3 NPs were utilized in solar-light driven photocatalytic degradation of anionic Congo red (CR) and Bromophenol blue (BPB) dye. Experimental results indicated the remarkable photocatalytic activity of α-Fe2O3 NPs, and approximately 89.42% of CR and 87.96% of BPB was degraded in 240 min under sunlight irradiation at ambient conditions. The photocatalytic degradation experiments were also performed under different reaction conditions which followed the pseudo-first-order kinetics. The presence of reactive species generated in the reaction system liable for the CR and BPB degradation were corroborated through radical quenching experiments and further confirmed by EPR analysis. The excellent photocatalytic potential of α-Fe2O3 NPs suggested that the synthesized nanoparticles could effectually be applied to remove organic dyes from the wastewater.