Green synthesis, characterization and catalytic degradation studies of gold nanoparticles against congo red and methyl orange

• Published in: Journal of photochemistry and photobiology. B, Biology Biology, 2018-01, Vol.178, p.33-39
• Main Authors: Umamaheswari, C., Lakshmanan, A., Nagarajan, N.S.
• Format: Article
• Language: English
• Subjects: Absorption spectra; Biocompatibility; Catalysis; Chemical synthesis; Congo red; Dalbergia coromandeliana; Dalspinin; Degradation; Dyes; Electron diffraction; Electron microscopy; Fourier transforms; Gold; Gold nanoparticles; Infrared spectroscopy; Kinetics; Methyl orange; Nanoparticles; Powder; Reaction kinetics; Spectroscopy; Surface plasmon resonance; Transmission electron microscopy; X-ray diffraction
• ISSN: 1011-1344; 1873-2682
• DOI: 10.1016/j.jphotobiol.2017.10.017

The present study reports, novel and greener method for synthesis of gold nanoparticles (AuNPs) using 5,7-dihydroxy-6-metoxy-3',4'methylenedioxyisoflavone (Dalspinin), isolated from the roots of Dalbergia coromandeliana was carried out for the first time. The synthesized gold nanoparticles were characterized by UV–Vis spectroscopy, high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The observed surface plasmon resonance (SPR) at 532nm in the UV–Vis absorption spectrum indicates the formation of gold nanoparticles. The powder XRD and SAED pattern for synthesized gold nanoparticles confirms crystalline nature. The HR-TEM images showed that the AuNPs formed were small in size, highly monodispersed and spherical in shape. The average particle sizes of the AuNPs are found to be ~10.5nm. The prepared AuNPs were found to be stable for more than 5months without any aggregation. The catalytic degradation studies of the synthesized AuNPs towards degradation of congo red and methyl orange, showed good catalytic in the complete degradation of both the dyes. The reduction catalyzed by gold nanoparticles followed the pseudo-first order kinetics, with a rate constant of 4.5×10−3s−1 (R2=0.9959) and 1.7×10−3s−1 (R2=0.9918) for congo red (CR) and methyl orange (MO), respectively. [Display omitted] •The present biotechnological method is capable of producing gold nanoparticles by a green, high yield and fast approach.•In this study Dalspinin, an isoflavone used as a reducing as well as stabilizing agent in synthesis of AuNPs.•The average mean size of the gold nanoparticles found to be 10.5±0.37nm and spherical in shape.•The phyto-synthesized AuNPs possessed good catalytic reduction potential against Congo red and methyl orange.