Green synthesis of NiFe nano particles using Punica granatum peel extract for tetracycline removal

Abstract

This study investigated the formation of NiFe nanoparticles (nano zero valent iron/Nickel) by the green synthesis approach using ethanolic extract of Punica granatum (pomegranate) peels. Detailed antioxidant analyses and gas chromatography–mass spectrometry (GC-MS) results established that 2-furancarboxaldehyde 5-(hydroxymethyl), 1,2-Di(2-furyl)-1,2-ethanedione and 2,5-furandicarboxaldehyde present in the extract could serve as reducing agents during synthesis. The synthesized particles were characterized through various techniques like X-Ray Diffraction (XRD), FE-SEM (Field Emission-Scanning Electron Microscopy), FT-IR (Fourier Transform-Infra Red) spectroscopy, Brunauer Emmett-Teller (BET) surface analyses. The biosynthesized NiFe nanoparticles were further used for the tetracycline (TC) removal from aqueous solutions. Tetracycline removal was optimized with respect to nanoparticle concentration using Response Surface Methodology (RSM) approach. Under the optimized conditions (initial TC concentration: 20 mg/L; NiFe nanoparticles concentration: 300 mg/L; interaction time: 90 min) 93 ± 1.55% TC removal could be obtained. The mechanism(s) of TC removal by NiFe nanoparticles was studied with help of LC-MS, TOC (Total Organic Carbon), FTIR, XRD, and ORP (Oxidation-reduction potential) analyses. It was observed that both the sorption and degradation phenomena were involved in TC removal. The application potential of the NiFe nanoparticles was investigated in ground water and lake water samples spiked with TC and the removal was found to be 77 ± 1.12 and 70 ± 2.02% respectively. Residual toxicity assays with TC by-products after interaction with NiFe nanoparticles were conducted on algal and bacterial species with the results indicating that the TC by-products were less toxic as compared to TC alone.