Synthesis of iron nanomaterials with Terminalia catappa L. leaves extract and application to stimulate corn seed germination

Abstract

Green chemistry-based synthesis of nanomaterials has emerged as a promising approach due to its environmental friendliness and high potential for sustainable agricultural applications. In this study, Terminalia catappa L. leaf extract was employed as a biological reducing agent to convert ferric ions (Fe³⁺) into metallic iron (Fe^o), thereby synthesising iron nanoparticles. The extract was obtained by ultrasonic-assisted extraction using 70% ethanol, with total polyphenol and flavonoid contents of 85.12±0.97 mg GAE/g DW and 104.6±8.72 mg QE/g DW, respectively. The effects of Fe³⁺ precursor concentration, reaction temperature, and reaction time on nanoparticle synthesis were investigated and optimised based on experiments evaluating the germination-stimulating effects on maize seeds. The structural and morphological characteristics of the synthesised material were analysed using XRD, FTIR, and SEM techniques. The results revealed a distinct diffraction peak of Feo at 2θ=45.7^o, with particle sizes ranging from 20 to 100 nm and an average size of ∼80 nm. The green-synthesised iron nanoparticles exhibited a notable stimulatory effect on seed germination, suggesting their potential as a bioactive nanomaterial for stimulating plant growth.