Green Synthesis of Silver Nanoparticles Using Tea Leaves from Three Different Elevations

• Published in: ChemistrySelect (Weinheim) 2020-04, Vol.5 (14), p.4239-4246
• Main Authors: Chandra, Abhishek, Bhattarai, Ajaya, Yadav, Ashok K., Adhikari, Janak, Singh, Man, Giri, Basant
• Format: Article
• Language: English
• Subjects: Camellia Sinensis; cultivation elevation; mercury; sensors; surfactants
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.201904826

Green synthesis of nanoparticles offers numerous advantages over the conventional methods. This work provides a comprehensive understanding on the effect of tea cultivation elevation on the formation of silver nanoparticles (AgNPs) using green tea (Camellia Sinensis) leaves. The green tea leaves were collected from three different elevations: 86, 1700, and 2000 m above sea level in eastern Nepal. We found that AgNPs synthesized using tea leaves from 1700 m were homogeneously dispersed and smallest size, when compared to AgNPs synthesized using tea leaves from remaining two elevations. All aqueous dispersed AgNPs were sensitive towards mercury (II) ion over a range of other metal ions tested. However, the AgNPs synthesized using tea leaves from 1700 m resulted in better detection limit of 9.79 μM for sensing mercury (II) ions. Interestingly, the nanoparticles when additionally stabilized in aqueous trimethyloctylammonium bromide, a cationic surfactant among seven other surfactants tested, improved the detection limit to 0.71 μM. Tea leaves cultivated on hill site produced homogeneous and smaller sized silver nanoparticles (AgNPs) compared to tea leaves from other two sites. Thus synthesized AgNPs from hill site tea leaves were more sensitive to sense Hg+2 than other two. Interestingly when dispersed in cationic surfactant, the same AgNPs solution was able to detect even lower concentrations of Hg+2.