Biosynthesis of NiFe2O4 nanoparticles using Murayya koenigii for photocatalytic dye degradation and antibacterial application

Abstract

Biosynthesis of nickel ferrite (NiFe2O4) nanoparticles (NPs) using an aqueous extract of Murraya koenigii (M. koenigii) leaves is a novel, environmentally benign and cost effective method. NiFe2O4 NPs were characterized by different spectroscopic and microscopic techniques, including Ultraviolet–Visible (UV–Vis) spectroscopy, X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, Thermogravimetric Analysis (TGA), Transmission Electron Microscopy (TEM), High-Resolution Scanning Electron Microscopy (HRSEM), Energy-dispersive X-ray spectrometry (EDX) and Vibrating-Sample Magnetometer (VSM). The observed results revealed that prepared NiFe2O4 NPs are highly pure, crystalline, partially spherical with an average size of 2–6 nm and attribute magnetic properties. The magnetization of the obtained biosynthesized nanoparticles is noticed ∼5.2 emu/g at 10 K Oe. The NiFe2O4 NPs exhibited a heterogeneous photo Fenton's catalytic feature in the presence of oxalic acid at ambient conditions. The effects of pH, dosage of NiFe2O4 catalyst and doses of oxalic acid on the degradation efficiency of 10 mg/L MB dye were assessed. The optimal degradation efficiency of ⁓ 98.5% was achieved within 70 min, and the observed results elucidated that the photocatalytic reactions follow first-order chemical kinetics. Thermodynamic parameters such as activation energy (Ea), enthalpy of activation (ΔH‡), entropy of activation (ΔS‡), and free energy of activation (ΔG‡) were evaluated, applying Arrhenius and activated complex theory ascertained the endothermic, less random and nonspontaneous features of photocatalytic process. NiFe2O4 NPs were also tested against different bacteria and found to have antibacterial properties. Hence, magnetic NiFe2O4 NPs can be exploited for its multifunctional applications, and specifically for the remediation of dye-contaminated wastewater.