Abstract
A facile and eco-friendly method for green synthesis of silver nanoparticles (AgNPs) has been developed using gum tragacanth (GT) (Astragalus gummifer), an abundantly available natural phyto-exudate in India, employing a novel method of ultrasonication process. Silver nanoparticles were prepared by the reduction of silver nitrate solution by the aqueous extract of gum tragacanth by ultrasonication method at 45 °C for about 45 min. The aqueous extract of the gum acts as a reducing as well as stabilizing agent. The resultant AgNPs were characterized by ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. The influence of gum concentration and silver precursor concentration on the synthesis of AgNPs was studied. The role and effectiveness of nanoparticles in the catalytic reduction of a cationic dye methylene blue (MB), and an anionic azo dye Congo red (CR), were also studied. FTIR analysis revealed that –OH groups present in the gum matrix might be responsible for the reduction of Ag+ into AgNPs. The X-ray diffraction studies indicated that the resulting AgNPs were highly crystalline with face-centered cubic geometry. TEM studies showed that the average particle size of the synthesized AgNPs was 18 ± 2 nm. The study highlights the green synthesis of GT-capped AgNPs and the rapid reduction of carcinogenic and toxic contaminants such as MB and CR with the help of GT-capped AgNPs in an eco-friendly manner.
Highlights
A facile and eco-friendly method for green synthesis of silver nanoparticles (AgNPs) has been developed using gum tragacanth (GT) (Astragalus gummifer), an abundantly available natural phyto-exudate in India, employing a novel method of ultrasonication process
The absorption behavior of AgNPs was attributed to the surface plasmon resonance (SPR), which results from the coherent oscillation of electrons in the conduction band induced by the electromagnetic field, and a characteristic surface plasmon absorption band can be seen in the spectral range of 418–428 nm (Rai et al 2009)
The role of AgNO3 concentration on the production of AgNPs was studied by UV-Vis spectra of the synthesized AgNPs with different concentrations of AgNO3 (0.1 to 0.5 %) with 0.5 % GT for 45 min of ultra sonication at 45 °C (Fig. 1)
Summary
A facile and eco-friendly method for green synthesis of silver nanoparticles (AgNPs) has been developed using gum tragacanth (GT) (Astragalus gummifer), an abundantly available natural phyto-exudate in India, employing a novel method of ultrasonication process. In recent times, play a crucial role in a multitude of applications as they were proved to exhibit remarkable improvements in their electronic, physical, chemical, optical, and biological properties when compared to their pure metal counterparts (Thakkar et al 2010). There are many natural biopolymers used for metal nanoparticle synthesis such as gum kondagogu (Rastogi et al 2014), salmalia malabarica gum (Murali krishna et al 2015) guar gum (Pandey et al 2012, Pandey and Mishra 2011, Pandey and Mishra 2013, Pandey et al 2013, Pandey and Mishra 2014, Pandey and Mishra 2016), chitosan (Wang et al 2015), gum ghatti (Kora et al 2012) and cyclodextrin (Maciollek and Ritter 2014) These biopolymers act as stabilizing as well as reducing agents. The characteristics of the metal nanoparticles were further improved when these metal nanoparticles were reacted with natural gums such as gum tragacanth (GT) (Raveendran et al 2003) due to the increase in the number of active sites, i.e., reactive functional groups on nanoparticles through capping process
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
