GREEN SYNTHESIS OF GOLD NANOPARTICLES AND THEIR ENHANCED CATALYTIC APPLICATION IN ORGANIC REDUCTION

Abstract

Water pollution stemming from various sources, including organic dyes, pesticides, and organic compounds,
remains a pressing global concern. In this study, a green one-step synthesis method using Paramignya
trimera’s extract as reducing and stabilizing agent was successfully applied to synthesizegold nanoparticles
(AuNPs) for the effective degradation of organic dyes. The AuNPs exhibit a spherical shape, ranging from
18 to 24 nm, and are uniformly distributed as observed through TEM and SEM measurements. The
exceptional stability of the AuNPs suspension is attributed to the electrostatic attraction mechanism, as
indicated by the high zeta potential of -23.8 mV, and the protective role played by the organic layer
surrounding the AuNPs. The research results regarding the catalytic capabilities of the material reveal that
AuNPs effectively serve as catalysts for the reduction of two organic dyes, methylene blue (MB) and
bromocresol green (BG), forming their respective complex compounds. The corresponding rate constants
for these reactions are determined as follows: k = 0.0152 s-1
for MB and k = 0.0056 s-1
for BG, while the
activation energies of these reactions are found to be -14.62 kJ/mol for BG, and -16.05 kJ/mol.