Synthesis and Characterization of Silver Nanoparticles Using Amberlite LA-2 Functionalized with Benzoyl Thiourea as a Capping Agent

In this study, the synthesis and characterization of silver nanoparticles (AgNPs) using Amberlite LA-2 functionalized with benzoyl thiourea as a capping agent were investigated. Silver nanoparticles were prepared from silver nitrate using the chemical reduction method in the presence of sodium borohydride as a reducing agent and Amberlite LA-2 bearing benzoyl thiourea (ALA-BTU) as a capping agent. The reaction conditions, such as reactant concentrations, reaction time, pH, and temperature, are optimized to achieve the desired nanoparticle size and morphology. Silver nanoparticles were characterized by using different techniques, including UV‒visible spectroscopy (UV‒Vis), infrared spectroscopy (FTIR), and dynamic light scattering (DLS). The surface plasmon resonance of silver nanoparticles was obtained at 400 nm. The average diameter of the silver nanoparticles was in the range of 86.36 to 103.4 nm, as determined by DLS; however, the average diameter was 3 nm, as determined by TEM. The absorbance of the tested solutions was found to increase with increasing AgNO₃ concentration and pH; however, the absorbance decreased with increasing temperature, time and ionic strength. The silver nanoparticles and ALA-BTU showed moderate antibacterial activity against Staphylococcus bacteria. However, they exhibited insignificant antimicrobial effects against Streptococcus, E. coli, and Pseudomonas aeruginosa bacteria.