Removal of Hazardous Dyes from Aqueous Solutions Using Green-Synthesized Magnetite Nanoparticles via Bauhinia Variegata Leaf Extract: Characterization, Adsorption, Kinetics, and Antimicrobial Studies

Abstract

Green synthesis represents an environmentally friendly and low-cost approach to obtaining Magnetite nanoparticles. In the present study, we synthesized Magnetite nanoparticles (Fe₃O₄-BV NPs) using aqueous leaf extract from Bauhinia variegata. The Fe₃O₄-BV NPs were characterized using UV-visible spectrophotometry, magnetic property, PXRD, FT-IR, SEM, SEM-EDX, TEM, and SAED. As determined from PXRD patterns, the resulting spherical NPs were pure, with a crystallite size of 11.98 nm. VSM studies revealed the superparamagnetic behavior of the NPs. Fe₃O₄-BV NPs were efficient adsorbents for removing crystal violet (CV) and fluorescein sodium (FS) dyes from an aqueous solution. Remarkably, 99% of CV dye was adsorbed in 30 minutes and 95% of FS dye was adsorbed in 90 minutes. Different adsorption models were applied to characterize the dye adsorption process. The maximum equilibrium adsorption capacity of 440.76 mg g^-1 and 346.32 mg g^-1 was achieved for CV and FS dyes, respectively. Antimicrobial activity was evaluated using the bacterial strains, gram-positive Bacillus cereus, and gram-negative Escherichia coli. The study showcased the potential of Fe₃O₄-BV NPs in removing hazardous dyes from aqueous solutions.