GREEN SYNTHESIS OF GOLD NANOPARTICLES BASED ON EXTRACT FROM AGRICULTURAL WASTE OF PINEAPPLE PEELS FOR CATALYTIC REDUCTION TOWARD 4-NITROPHENOL

Abstract

Biogenic gold nanoparticles (AuNPs) were successfully synthesized by a simple single-step method using extract from agricultural waste of pineapple peels (PP) as reducing as well as stabilizing agent. Major parameters affecting the formation of PP-AuNPs, including gold ions concentration, reaction time, and reaction temperature were optimized using ultraviolet-visible (UV-Vis) measurements at characteristic maximum absorbance of 560 nm. The functional groups responsible for reducing gold ions and capping AuNPs were examined by Fourier-transform infrared (FTIR) spectroscopy. Powder X-ray diffraction (XRD) analysis confirmed the crystalline nature of PP_AuNPs. Transmission electron microscopy (TEM) measurements showed that the biosynthesized PP-AuNPs were mostly spherical with an average size of 5-15 nm. The gold nanoparticles also demonstrated excellent catalytic activity for the complete reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH₄ within 10 min with reaction rate constant of 0.233 min^-1.