Algae-Mediated Synthesis and Structural Characterization of Silver Nanoparticles from Laurencia papillosa and Galaxaura rugosa

Laurencia papillosa and Galaxaura rugosa-mediated silver nanoparticles (AgNPs) were successfully synthesized by a simple reduction method. The AgNPs were characterized using UV–visible spectroscopy, X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), Selected area electron diffraction (SAED), scanning electron microscopy (SEM), energy dispersive analysis of X-rays (EDAX), zeta potential and fourier transform infrared spectroscopy (FTIR). Rapid color change from yellow to dark brown and UV-visible absorption peaks for L. papillosa at 398 and 458 nm and G. rugosa at 409 nm, respectively, supported the early formation of AgNPs. Biogenic AgNPs were face-centered cubic, crystalline and spherical, with mean diameter sizes varying from 6.9 to 15.0 nm for L. papillosa and 5.8 to 13.8 nm for G. rugosa, according to XRD, TEM and SAED analyses. The high abundance of AgNPs produced by L. papillosa and G. rugosa was visible in SEM, and the particles almost resembled spheres and in aggregates. For L. papillosa and G. rugosa, the biosynthesized AgNPs had a negative surface charge with zeta potential values of -17.8 mV and -16.4 mV, respectively. According to FTIR findings, functional groups significantly contribute to the bioreduction of silver ions and the stability of AgNPs. This approach is simple and safe for the environment, and it can be used for projects with a focus on the environment.