Himalayan lichen biomass for green synthesis of silver nanocolloids: growth kinetics, effect of pH and metal sensing

Autor: Nirmala Sharma, Surendra Kumar Gautam, Achyut Adhikari, Bhanu Bhakta Neupane
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Royal Society Open Science, Vol 11, Iss 3 (2024)
Druh dokumentu: article
ISSN: 2054-5703
DOI: 10.1098/rsos.231633
Popis: 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 Hypotrachyna cirrhata, 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 × 10−3 min−1. Transmission electron microscopy showed a narrow particle size distribution with a mean particle size of 11.1 ± 3.6 nm (n = 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 Hg2+ and Cu2+ ions in spiked water samples. The limit of detection and calibration sensitivity for Hg2+ and Cu2+ ions were found to be 1 and 5 mg l−1 and 2.9 × 10−3 and 1.6 × 10−3 units ppm−1, respectively. These findings suggested that spherical silver nanoparticles with a narrow particle size distribution can be synthesized on a laboratory scale using an aqueous H. cirrhata lichen extract, and the colloidal solution can be used for the detection of selected heavy metals in water samples.
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