Fabrication of iron nanoparticles using Parthenium: A combinatorial eco-innovative approach to eradicate crystal violet dye and phosphate from the aqueous environment

Abstract

Parthenium (congress grass) is a noxious weed having harmful effects on agricultural crops due to its allelopathic effect it grows generally in America, Asia, Africa and Australia. Usage of Parthenium for nanoparticles green synthesis provides a cost effective, easy, non-toxic and environmentally convenient method as well as help in management of this weed. It was used in this study for the green synthesis of iron nanoparticles (Pa-INPs). The synthesized nanoparticles were characterized through Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and particle size analysis (PSA). The nanoparticles were applied to remove crystal violet (CV) and phosphate from the aqueous solution by adsorption technology. The adsorption process of CV and phosphate was optimized for higher removal by varying one parameter at a time. The synthesized nanoparticles successfully removed CV and phosphate from the aqueous solution. The maximum adsorption efficiencies were achieved approximately 95 % (at 10 mg/L initial concentration) and 76 % (at 5 mg/L initial concentration) for CV and phosphate, respectively. The adsorption process was depended on solution pH and pHZPC of the nanoparticles. After adsorption, the spent iron nanoparticles were regenerated and their recycling efficiency was also tested. The adsorption study was analysed by adsorption isotherms, kinetics and the thermodynamic modelling. CV adsorption was found to be exothermic, while the behaviour of phosphate adsorption was observed to be endothermic in nature. The experimental results of both the pollutants were best supported by Freundlich isotherm model and pseudo-second-order kinetic model.