Utilization of Silver Nanoparticles for Practical Removal and Detection of Pb²⁺ and Hg²

The presence of Pb²⁺ and Hg²⁺ in the environment is a matter of significant concern because of their potential harm to living organisms. This study presents an innovative and practical method for the detection of Pb²⁺ and Hg²⁺ using yellow silver nanoparticles (YAgNPs). These nanoparticles were synthesized through a chemical reduction process employing sodium borohydride (NaBH₄) as the reducing agent and trisodium citrate (TSC) as the stabilizing agent. YAgNPs exhibit remarkable affinity for Pb²⁺ and Hg²⁺. In the presence of Pb²⁺, the formation of distinct yellow precipitates, accompanied by a clear supernatant solution, was observed. In addition, the presence of Hg²⁺ led to the formation of distinct white and cloudy precipitates accompanied by a clear supernatant solution. These characteristic changes led to the highly selective detection of Pb²⁺ and Hg²⁺ over other metal ions. The precipitation of YAgNPs in the presence of Pb²⁺ could be attributed to electrostatic interactions involving functionalized citrate anions, which led to coprecipitation of the AgNPs and Pb²⁺ complex. On the other hand, the conspicuous white precipitate in the presence of Hg²⁺ could be attributed to the amalgamation of Hg and Ag caused by the redox reaction of AgNPs and Hg²⁺. The calculated detection limits of Pb²⁺ and Hg²⁺ are 0.0282 mM and 0.0570 mM, respectively. Crucially, this study demonstrates the successful application of YAgNPs in three authentic samples without necessitating preliminary sample pretreatment. The findings underscore the robust capacity of YAgNPs to effectively detect Pb²⁺ and Hg²⁺ in real samples, thus positioning these nanoparticles as the highly promising candidates for the initial screening of Pb²⁺ and Hg²⁺ in environmental samples. Importantly, these nanoparticles exhibit potential as the efficacious agents for the removal of Pb²⁺ and Hg²⁺ during wastewater treatment processes, signifying importance in addressing environmental Pb²⁺ and Hg²⁺ contamination concerns.