Sharma Nirmala, Gautam Surendra Kumar, Adhikari Achyut, Bhakta Neupane Bhanu
Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu 44613, Nepal.
Department of Chemistry, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu 44605, Nepal.
R Soc Open Sci. 2024 Mar 6;11(3):231633. doi: 10.1098/rsos.231633. eCollection 2024 Mar.
Lichen is one of the most abundant non-vascular biomasses; however, a systematic study on the application of biomass in nanomaterial synthesis is very limited. In this study, an aqueous lichen extract was obtained from , one of the most abundant Himalayan lichen biomasses, using a simple cold percolation method. The effects of extract-to-silver nitrate mixing ratio, pH and waiting time on the growth and stability of nanoparticles were systematically explored. The rate constant for bio-reduction was found to be 5.3 × 10 min. Transmission electron microscopy showed a narrow particle size distribution with a mean particle size of 11.1 ± 3.6 nm ( = 200). The X-ray diffraction and selected area electron diffraction techniques confirmed the formation of cubic crystals. The synthesized colloidal solution showed excellent response to Hg and Cu ions in spiked water samples. The limit of detection and calibration sensitivity for Hg and Cu ions were found to be 1 and 5 mg l and 2.9 × 10 and 1.6 × 10 units ppm, respectively. These findings suggested that spherical silver nanoparticles with a narrow particle size distribution can be synthesized on a laboratory scale using an aqueous lichen extract, and the colloidal solution can be used for the detection of selected heavy metals in water samples.
地衣是最丰富的非维管生物质之一；然而，关于生物质在纳米材料合成中的应用的系统研究非常有限。在本研究中，使用简单的冷渗滤法从喜马拉雅地区最丰富的地衣生物质之一中获得了地衣水提取物。系统地探索了提取物与硝酸银的混合比例、pH值和等待时间对纳米颗粒生长和稳定性的影响。发现生物还原的速率常数为5.3×10⁻³ min⁻¹。透射电子显微镜显示粒径分布狭窄，平均粒径为11.1±3.6 nm（n = 200）。X射线衍射和选区电子衍射技术证实了立方晶体的形成。合成的胶体溶液对加标水样中的汞离子和铜离子表现出优异的响应。汞离子和铜离子的检测限和校准灵敏度分别为1和5 μg l⁻¹以及2.9×10⁻²和1.6×10⁻² ppm单位。这些发现表明，使用地衣水提取物可以在实验室规模合成粒径分布狭窄的球形银纳米颗粒，并且该胶体溶液可用于检测水样中的特定重金属。
