Heavy metals, organic and un-natural dyes cause countless serious complications to human health and eco-system, however, manipulation of such chemicals are unescapable due to their widespread applications in diverse meadows of science and technology. With the hasty growth of industries for instance ore mining, textile industries, paper and paint industry, fertilizers and pesticide industries etc., an extensive aggregate of dyes, heavy metals and pigments are predisposed afterward the industrial progressions (Mance, 2012). The effluents commencing from such industries are discharged-off into natural-surfaces and ground-water resources. These toxic-effluents amends the composition of surface-water and consequently sound effects to the healthiness of living-beings. With the passageway of time, pigments and dyes available in water submit yourself to degradation chemically and transformed to supplementary hazardous toxic-chemical entities (Chang & Chen, 2009). Finally, these heavy metals and dyes possibly will indirectly or directly enter the food-web and originate unadorned toxic-impacts on surroundings. Thus, it is lethal to become aware of and reduce such engineering-wastes from water.
There are numerous techniques reported previously for the treatment of unnatural-dyes filthy-water. These comprise that, catalytic reduction (Begum et al., 2018), photo-catalytic degradation (Saeed, Ahmad, Boddula, ul Haq, & Azhar, 2018), advance oxidation routes (Qiu et al., 2017), membrane matrices (Fersi, Gzara, & Dhahbi, 2005), bio-remediation (Mani & Kumar, 2014), adsorption (Chongmin Liu, Wu, Tran, Zhu, & Dang, 2018). Amongst them, reductive squalor by employing nanocatalyst partake been pragmatic on broad-spectrum for the treatment of dyes in aqueous solutions prior to its proficiency, clean dispensation, and cost effectiveness (Hassan et al., 2011; Hu et al., 2015). Reduction of such dyes by nanocatalyst transfigure them to gamely biodegradable out-puts, that be able to further processed on requirement (Hassan et al., 2011). Metal based nanocatalyst for such reduction feedback mainly count on noble metals, like Ag and Au (P. Wang et al., 2008; Yasin, Liu, & Yao, 2013) in line for their extraordinary stability and high specific area. Thus, starved of appropriate surface stabilizers, these nanocatalysts endures aggregation, which can primarily domino effect of degradation of their catalytic-activities and lifetime (Lin, Tsai, Chen, Lin, & Chen, 2004). Therefore, this is vitally important to stabilize nanocatalyst with accurate-ligands to enhance its efficiency and life-span. Several routes for preparing metal nanoparticles have been developed i.e., co-precipitation (Kim, Kim, & Lee, 2003), hydrothermal synthesis (Daou et al., 2006), sol-gel method (Chao Liu, Zou, Rondinone, & Zhang, 2001), inert gas condensation (Pérez-Tijerina et al., 2008), laser ablation (Amendola & Meneghetti, 2009), sputtering (Rane, Kanny, Abitha, & Thomas, 2018), template synthesis (Sreeram, Nidhin, & Nair, 2008), and biological synthesis (Devi et al., 2013). However, biological synthesis is the hot choice with advantages over physical and chemical methods as it is quick, eco-friendly, highly stable, and cost-effective. Biological synthesis does not acquire any culture growth and does not produce toxic residues to contaminate the atmosphere (Kulkarni & Muddapur, 2014).
Catalytic reduction mainly depends upon the morphology (Sun, 2010) and surface area of the nano-structures (Das & Soni, 2017) i.e., nanoparticles (Yousaf, Mehmood, Ahmad, & Raffi, 2020), nano-rods (Sawant & Sawant, 2020), nano-spheres (Ramya, Jyothi, Vardhan, Gopal, & Desai, 2020), nanotubes (Nadagouda, Speth, & Varma, 2011) and nanowires (Goh et al., 2012). Among them nanowires have grabbed the prime focus of the material scientists due to their excellent features like surface area, micro-porous structural features, highest contact area with adsorbate surfaces (Z. Wang, Liu, Chen, Wan, & Qian, 2005). Lin Bao et al. has reported the synthesizes of nanowires via green approach by using poly-vinyl acetate (PVA) polymer back-bone as a stabilizing agent due to the lower stability of Ag-nanowires (Ag-NWs) (Luo, Yu, Qian, & Gong, 2006). Many serious attempts have been made to enhance the stability of Ag-NW by using stabilizers like polymer matrices (PVA, PPy EG, and glucose) (Zhu et al., 2016), ITO glass electrode base (Sim et al., 2016) and electrostatic charge stabilizers (Yang et al., 2011). The synthesis of Ag-NW via a facile, green and eco-friendly routes without any external stabilizers and pro-longed shelf-life is still a great challenge for the scientists (Guo, Chen, Wang, Jiang, & Wang, 2020).
Herein, we are reporting a facile and green approach to synthesize the Ag-Nanowires (Ag-NW) by using Psidium guajava seed extract to stabilize the nanowires, without any external stabilizers like ITO-glass electrode, electrostatic charge which was the classical approach to synthesize the nanowires. The plant seed extract by dissolving 0.1 g of the dry and finely divided form in 100 mL water at 60°C for 50 minutes followed by the vacuum filtration and used as a precursor for the reduction of silver ions. Then freshly prepared 0.1 mM solution of AgNO3 was taken in conical flask. The addition of 5 mL of Psidium guajava seed extract was done to AgNO3 under continues stirring and UV-irradiation of 265 nm wavelength white light, and stirred the reaction mixture for 4 hours. This is first effort to synthesize Ag-NW via a green, eco-friendly and template free pathway, with greater stability of Ag-NW.