Alga‐mediated facile green synthesis of silver nanoparticles: Photophysical, catalytic and antibacterial activity

Abstract

A facile, convenient and green method has been employed for the synthesis of silver nanoparticles (AgNPs) using dried biomass of a green alga, Chlorella ellipsoidea. The phytochemicals from the alga, as a mild and non‐toxic source, are believed to serve as both reducing and stabilizing agents. The formation of silver nanoparticles was confirmed from the appearance of a surface plasmon resonance band at 436 nm and energy dispersive X‐ray spectroscopy. The transmission electron microscopy images showed the nanoparticles to be nearly spherical in shape with different sizes. A dynamic light scattering study revealed the average particle size to be 220.8 ± 31.3 nm. Fourier transform infrared spectroscopy revealed the occurrence of alga‐derived phytochemicals attached to the outer surface of biogenically accessed silver nanoparticles. The powder X‐ray diffraction study revealed the face‐centred cubic crystalline structure of the nanoparticles. The as‐synthesized biomatrix‐loaded AgNPs exhibited a high photocatalytic activity for the degradation of the hazardous pollutant dyes methylene blue and methyl orange. The catalytic efficiency was sustained even after three reduction cycles. A kinetic study indicated the degradation rates to be pseudo‐first order with the degradation rate being 4.72 × 10−2 min−1 for methylene blue and 3.24 × 10−2 min−1 for methyl orange. The AgNPs also exhibited significant antibacterial activity against four selected pathogenic bacterial strains.

Facile combustion synthesis of Ag2O nanoparticles using cantaloupe seeds and their multidisciplinary applications

“…This technique will also reduce pollution yet allowing reasonable quantities of useful materials to be synthesized easily in an eco-friendly manner. [26][27][28][29][30][31][32][33] NPs have small size and very large surface area, which play an important role in their excellent biological activity, as it provides suitable conditions for their interaction with the biological systems, which is not the case with bulkier materials. [34][35][36][37][38][39] Melon seeds are generally discarded as a waste or removed from the fruits and planted, but not used for any other beneficiary aspects.…”

A Review of Green Synthesis of Metal Nanoparticles Using Algae

“…A shift of the color of the reaction mixture to brownish violet or a change to violet suggests the formation of silver nanoparticles, and a change of the reaction mixture to purple or pink indicates the formation of gold nanoparticles (AuNPs). The biosynthesis of nanometals in the aqueous process is monitored using absorption spectroscopy in the UV-Vis spectral range (190–1,100 nm) since nanometals have striking optical properties due to surface plasmon resonance (SPR) ( Borah et al, 2020 ). The combined motions of the free electrons of metal nanoparticles in resonance with the light wave produce a special SPR absorption band (λ max ) that is dependent on size, shape, aspect ratio, and the dielectric constant of the metals.…”

Green Synthesis of Metal and Metal Oxide Nanoparticles: Principles of Green Chemistry and Raw Materials

“…There are different mechanisms of NPs formation using microorganisms [38]. A huge variety of nature biological materials, including plants [43][44][45][46][47][48][49][50][51], algae [52][53][54][55][56], fungi [57][58][59][60][61], yeast [62][63][64][65], bacteria [66][67][68][69], viruses [70], etc., can be used for the synthesis of "green" NPs (Figure 3).…”