SCIENCE ASIA

Volume 46, No. 06, Month DECEMBER, Year 2020, Pages 697 - 705

Biosynthesized silver nanoparticles from shoot and seed extracts of asphodelus tenufolius for heavy metal sensing

Marya Siraj, Zafar Ali Shah, Sami Ullah, Hamida Bibi, Muhammad Suleman, Afia Zia, Tariq Masood, Zafar Iqbal, Mudassar Iqbal

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Biosynthesis of silver nanoparticles (AgNPs) was achieved by treating the aqueous extract of shoots and seeds of Asphodelus tenufolius Cav with 1 mM silver nitrate solution at 30 ?C. The synthesized AgNPs were characterized through UV-Vis spectroscopy, Fourier Transform Infra-Red Spectroscopy and Scanning Electron Microscopy. The absorption maxima of shoot AgNPs was 444 nm and seed AgNPs was 448 nm. The FTIR spectral analysis showed a distinct peak stretching at 1380 cm?1 was clearly visible for both seed and shoot extract mediated AgNPs, and this was not present initially in crude extract of both samples. The SEM analysis confirmed the size (shoot = 58.2 nm and seed = 51.6 nm) of extract mediated AgNPs and shape (spherical and poly-dispersed) of the synthesized AgNPs. Both the synthesized AgNPs were stable at acidic pH 5.5 to fairly basic pH 9. Increase in acidity to pH 3.5 caused complete decomposition. The Metal (Cu, Ni, Co and Zn) sensing of different metal salt solutions (1 mM) confirmed the effect of copper salts (250 ?l/ml of AgNP solution) on both shoot and seed AgNPs while shoot AgNPs showed effect against Zn salt. This research can open a new domain for the detection of various heavy metals in aqueous solution through simple colorimetric determination.

Keywords

green synthesis of nanoparticles, eco-friendly silver nanoparticles, heavy metal detection, colorimetric

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