Experimental and computational study of ecofriendly synthesis of silver nanoparticles from natural extracts: Self-controlled nucleation and growth, and colorimetric detection of heavy metal ions

T Wonglakhon and N Jommala and S Laksee and P Nuengmatcha and B Ninwong and D Zahn and Y Thepchuay, SURFACES AND INTERFACES, 68, 106618 (2025).

DOI: 10.1016/j.surfin.2025.106618

We present an ecofriendly synthesis of silver nanoparticles (AgNPs) using the husk extract of Nypa fruticans, a largely unexploited biowaste, for effective colorimetric detection of heavy metal ions in aqueous solutions. Our one-step synthesis produces well-dispersed, highly stable AgNPs with an average size of similar to 4 nm, as determined by transmission electron microscopy. The compounds in the extract act as both reducing and stabilizing agents, facilitating self- controlled nucleation and growth, as supported by molecular simulations. The synthesized AgNPs were further characterized using UV-visible spectroscopy, energy dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and zeta potential measurements. Under optimized conditions, the AgNPs exhibit high selectivity toward Fe2+ ions, producing a distinct dark brown color that can be observed by the naked eye, while showing almost no response to other tested heavy metal ions. The calibration curve for the Fe2+ detection showed excellent linearity (r(2) = 0.9959) with a detection limit of 0.24 ppm. Additionally, the AgNPs demonstrated excellent (> 94 %) Fe2+ recovery in real water samples. Through quantum chemical calculations and molecular dynamics simulations, we provided atomic-level insights into the mechanisms of Fe2+ detection. This present work thus highlights the potential of biomass extracts for green nanomaterial synthesis and environmental applications.

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