The Role of pH in Synthesis Silver Nanoparticles Using Pometia pinnata (Matoa) Leaves Extract as Bioreductor

Green synthesis of silver nanoparticles (AgNPs) using plant extract have been developed due to ecological friendly and their simple procedure. Plant contains bioreductor to reduce silver precursor into nanoparticles. Plant compound beside of their medicinal properties also can be functional for this biosynthesis process. The synthesis process can be affected by pH, which can determine the shape and size from AgNPs. Therefore, in this research biosynthesis of AgNPs has been done to study the effect of aqueous extract pH on the AgNPs synthesize on acidic and alkaline condition. The synthesis was done by mixing 2% Matoa aqueous extract and 1 mM AgNO₃ each solution adjusted to 4 and 11, and 5 as the nature pH for comparison. The AgNPs were characterized based on color changes, UV-Vis spectrophotometers, TEM (Transmission Electron Microscopy), and PSA (Particle Size Analyzer). The UV-Vis spectrum had absorption between 400-500 nm. The TEM results showed that the shape of the nanoparticles produced varies considerably from triangles, spherical, and hexagons. The PSA results show that increasing pH tend to produce the small size of nanoparticles, which had moderately stable nanoparticle and moderate stability. This result showed that the AgNPs synthesized can be optimized by adjusting the pH to obtain particular shape and size from the AgNPs.