A green approach for the synthesis of silver nanoparticles by Chlorella vulgaris and its application in photocatalytic dye degradation activity

Biosynthesis of the silver nanoparticle (AgNPs) is gaining significant importance since it is eco-friendly and can withstand variable environmental conditions. In this present study, AgNPs have been synthesized by using a freshwater green alga, Chlorella vulgaris. For the improved production, experiments on the standardization of AgNPs synthesis were investigated at different parameters. The results affirmed that the synthesize of AgNPs was at 8:2 v/v in extract ratio, pH 12 in the solution of AgNO3, 3 mM in molarity of AgNO3, shaking process in the incubation of reactants and 24 h time in synthesis period. Further, synthesized AgNPs were characterized by using spectroscopic and microscopic techniques. The synthesized AgNPs showed the Surface Plasmon Resonance (SPR) peak between the 410–450 nm. Fourier Transform Infrared Spectroscopy (FTIR) revealed that the algal extract has stabilized with the nanoparticles by capping. The Field Emission Scanning Electron Microscopy (FESEM) analysis confirms the spherical shape of the AgNPs with an average size of 55.06 ± 9.67 nm. The X-ray diffraction (XRD) analysis showed a crystalline nature of the particle with an average size of 61.89 ± 12.13 nm. The photocatalytic decolorization of the methylene blue by using synthesized AgNPs was evaluated under the sunlight irradiation method. The synthesized AgNPs have shown 96.51% of photocatalytic decolorization activity by using methylene blue dye (100 ppm) within 3 h incubation time.