Utilization of the terrestrial weed Antigonon leptopus in the rapid and green synthesis of stable gold nanoparticles with shape/size control

Abstract

We report for the first time the utilization of a highly invasive weed Antigonon leptopus in synthesizing gold nanoparticles. For this purpose, aqueous extracts of the weed's leaves/stem/roots served the dual purpose of reducing gold ions to uncharged metal nanoparticles and then capping the nanoparticles thus formed to stabilize them. The synthesis occurs very swiftly leading to spherical, hexagonal, or triangular nanoparticles. The influence of the key variables that control the shape/size of the gold nanoparticles (AuNPs)—concentrations of the extract relative to Au (III), temperature, interaction time, stirring, and pH‐was studied employing UV–visible spectrophotometry, scanning electron microscopy, transmission electron microscopy, energy dispersive analysis of X‐rays, dynamic light scattering (DLS), X‐ray diffraction, and Fourier transform infrared spectroscopy. Besides being simple and rapid, the present process is distinguished by its ability to gainfully utilize an otherwise harmful plant in a manner which consumes little energy and generates no waste emissions. The AuNPs were found to catalyze the degradation of organic pollutants Congo red and Remazol Brilliant Blue R. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 20–33, 2016