Characterization and Aggregation of Silver Nanoparticles Dispersed in an Aqueous Solution

Colloidal solutions of silver nanoparticles were prepared by the chemical reduction method in which silver nitrate was used as a metal precursor and sodium citrate was used as a reducing as well as a stabilizing agent. UV-vis absorption spectra of the prepared colloids showed a surface plasmon resonance peak around 420 nm, indicating the formation of the nanoparticles. Size distribution analysis using a particle size analyzer showed that the average diameter of the synthesized nanoparticles is about 68 nm. This result was supported by the transmission electron microscope (TEM) images of the colloidal solutions. An X-ray diffraction (XRD) pattern was obtained to determine the crystalline structure of the silver nanoparticles. The aggregation of silver nanoparticles was investigated using different chemicals, mainly chlorides and hydroxides. These two categories of chemicals revealed different activity in the aggregating silver nanoparticles.