Facile green chemistry approach for environmental remediation: catalytic removal of toxic compounds and pathogens from water using Hyptis capitata plant mediated iron nanoparticles.

内容摘要

Green synthesis of iron nanoparticles (FeNPs) has gained more interest among researchers because it is an eco-friendly method that avoids harmful chemicals as stabilizing agents. These nanoparticles have been widely used for the degradation of pollutants and bacterial growth inhibition without affecting mammalian cells. In this study, FeNPs were prepared using an unconventional technique with Hyptis capitata (HC) leaf extract as both reducing and capping agent through the microwave method. The formation was confirmed by the color change of the reaction mixture and the characteristic UV-visible absorption peak obtained at 294 nm. The FT-IR interpretation shows the involvement of plant phytochemicals in the reduction and capping of nanoparticles. A broad and diffuse hump obtained in the X-ray diffraction (XRD) spectrum identifies an amorphous structure, and the zeta potential value (-30 mV) confirmed colloidal stability. Thermo-gravimetric analysis determined the thermal stability and degradation pattern of nanoparticles. The dynamic light scattering analysis of FeNPs confirms monodisperse particle size distribution. HR-TEM analysis proves the presence of spherical FeNPs with an average size of 3-6 nm, and the SAED pattern signifies the amorphous nature of FeNPs in the colloid. The EDX spectrum confirmed the presence of elemental iron. FeNPs demonstrated bacterial growth inhibition against Staphylococcus aureus and Escherichia coli, along with the catalytic efficiency to remove methyl orange and 4-nitrophenol from aqueous systems. These results reveal the potential of HC leaf extract-mediated FeNPs as a functionalized biomaterial for environmental remediation. This study presents the first report on the biogenic synthesis of iron nanoparticles (FeNPs) using Hyptis capitata leaf extract as a dual reducing and stabilizing agent. While green synthesis of noble metals is well-documented, this work bridges the gap in sustainable iron-based nanotechnology for environmental remediation. The novelty lies in the dual-functional efficiency of these phytogenic FeNPs, which demonstrate simultaneous high-rate catalytic degradation of toxic organic pollutants and broad-spectrum antimicrobial action against waterborne pathogens. This “one-pot” green approach offers a low-cost, eco-friendly alternative to conventional chemical treatments, achieving rapid water purification under ambient conditions without the need for secondary stabilizers.