Low-cost and eco-friendly phyto-synthesis of silver nanoparticles using Cocos nucifera coir extract and its larvicidal activity

Phyto-synthesis of transition metal nanoparticles is gaining importance due to their biocompatibility, low toxicity, green approach and environmental friendly nature. We used mesocarp layer extract of Cocos nucifera and was assessed for the synthesis of silver nanoparticles. The reduction of silver ions occurred when silver nitrate solution was treated with aqueous extract of C. nucifera coir at 60 °C. Synthesized silver nanoparticles (AgNPs) particles were confirmed by analysing the excitation of surface plasmon resonance (SPR) using UV–vis spectrophotometer at 433 nm. Further TEM analysis confirmed the range of particle size as 23 ± 2 nm. The XRD spectrum showed the characteristic Bragg peaks of 1 1 1, 2 0 0, 2 2 0 and 3 1 1 facets of the face centered cubic silver nanoparticles and confirms that these nanoparticles are crystalline in nature. Gas chromatography–mass spectrometry (GCMS) of coir extract confirms the presence of hydrocarbon such as nonacosane and heptacosane which may possibly influence the reduction process and stabilization of silver nanoparticles. This is the first account of C. nucifera coir assisted synthesis of biogenic Ag nanoparticles; the nanoparticles are notably smaller and better faceted compared with those synthesized by A. squamosa extracts previously reported. Synthesized Ag nanoparticles were effective anti-larvicidal agent's against Anopheles stephensi and C. quinquefasciatus.

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► Cocos nucifera coir powder utilized in green manner.
► CAE role was proved for the preparation of silver nanoparticles.
► Hydrocarbons were identified by GCMS.
► Reducing and capping agent such as nonacosane and heptacosane were identified.
► Larvicidal activity evaluated against A. squamosa and C. quinquefasciatus.