A novel green synthesis and characterization of silver nanoparticles using gum tragacanth and evaluation of their potential catalytic reduction activities with methylene blue and Congo red dyes
Indana et al. Journal of Analytical Science and Technology
A novel green synthesis and characterization of silver nanoparticles using gum tragacanth and evaluation of their potential catalytic reduction activities with methylene blue and Congo red dyes
Murali Krishna Indana 0
Bhagavanth Reddy Gangapuram 0
Ramakrishna Dadigala 0
Rajkumar Bandi 0
Veerabhadram Guttena 0
0 Department of Chemistry, University College of Science, Osmania University , Hyderabad, Telangana State 500007 , India
Background: 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. Methods: 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. Results: 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. Conclusions: 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.
Gum tragacanth; Silver nanoparticles; Ultra-sonication; Catalytic reduction; Methylene blue; Congo red
Background
Metal nanomaterials, 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)
. These colloidal metal nanoparticles possess
unique physical properties owing to their extremely
small size and very high surface/volume ratio
(Pandey et al.
2016)
. The extremely small size of these metal
nanoparticles offers a very high reactive surface area that contributes
to their significant improvement in the properties in
comparison to their metal compatriots (Guo and Wang 2007).
The extremely small size of nanoparticles, especially in
the case of silver nanoparticles (AgNPs), finds their
utility in chemical applications such as catalysis, reduction,
stabilization, and colorimetric sensors
(Murugadoss and
Chattopadhyay 2008; Rastogi et al. 2014)
. The biological
applications involving the integration of nanoparticles
with biological molecules led to the development of
therapeutic medicines, diagnostic tools, antimicrobial
agents, drug delivery systems, bioimaging tools, labeling
agents, therapies in cancer, etc.
(Roy et al. 2015, Song
and Kim 2009, Kokila et al. 2015, Daniel and Astruc
2004)
.
The AgNPs are generally synthesized using various
methods such as chemical, photochemical,
electrochemical, laser ablation, γ-irradiation, and biological
conversion
(Solomon et al. 2007; Callegari et al. 2003; Pyatenko
et al. 2004; Li et al. 2007; Raju et al. 2014)
. The most
popular method by which AgNPs are synthesized is by
reducing agents such as sodium borohydride and sodium
citrate. Most of these synthetic methods are hazardous
since they employ toxic chemicals leading to
environmental degradation
(Mehndiratta et al. 2013)
and biological
hazards. Much effort is being focussed, in recent times, by
researchers to mitigate the impact of these harmful
chemicals’ utilization through the integration of “green chemistry
principles” for the synthesis of metal nanomaterials using
plant extracts (Parveen et al. 2016), biosurfactants, etc.
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
(...truncated)