Greener approach to synthesis of steady nano-sized gold with the aqueous concentrate of cotinus coggygria scop. Leaves

Abstract

There is a growing commercial attraction for nanoparticles because of their widespread feasibility in various fields for instance electronics, textiles, chemistry, medicine, energy and catalysis. This investigation describes an environmentally benign, cheap, and simple technique for biosynthesis of CCS-AuNPs utilizing the CCSL aqueous concentrate as a covering and reducing material. Various parameters influencing the reduction of Au3+ to Au0 were studied and the optimum conditions found as follows: chloroauric acid solution: 1 mM, CCSL aqueous extract: 20 g dry leaf /250 mL distilled water, volume proportion of chloroauric acid solution to CCSL aqueous solution: 24.8/0.2, pH: 3, response temperature: 60°C, and response time: 15 min. By stirring the reaction combination at 60°C for 10-15 minutes, the CCSL aqueous extract reduced Au3+ ions to Au0 and production of CCS-AuNPs was observed with the change of CCSL extract colour from light yellow to dark purple. Produced CCS-AuNPs were well defined by Ultraviolet-visible (UV-vis) absorption spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR spectroscopy), and Transmission electron microscopy (TEM). In the absorption spectrum, a symmetrical and prominent band observed in 500-600 nm wavelength range indicated that CCS-AuNPs formed. Synthesized gold nanoparticles at the optimum conditions are spherical (average particle size~17 nm) and remained stable for four months. Gold nanoparticles showed two fluorescent emission peaks at 444 nm and 704 nm whenever induced at 350 nm. Synthesized CCS-AuNPs showed lower antibacterial effect than plant extract.