Synthesis of Gold (Au) Nanoparticles for Mercury Adsorption

Abstract

Problem statement: Mercury is not only hazardous to human health and the environment but could also attack equipment components resulting in a mechanical failure and gas leakage. Approach: Describes the preparation of various sizes and shapes of Au nanoparticles for mercury adsorption by using polyol method under MW heating. Au nanoparticles have been synthesized by a polyol method under Microwave (MW) heating in the presence of Au seed ([Au]₁/[Au]₀ = 6 of molar ratio) and different Polyvinylpyrrolidone (PVP) concentrations (11.1, 22.2 and 33.3 mM). The amount of mercury adsorbed was determined by analyzing the concentration of mercury solution before and after the contacts with various sizes and shapes of Au nanoparticles. Results: When the lower PVP concentration (11.1 mM) was used, polygonal and spherical nanoparticles were dominantly present, while spherical nanoparticles were preferentially form by using higher PVP concentrations (22.2 and 3.33 mM). It was found that the diameter and length of Au nanoparticles decreased with increasing PVP concentrations. When Au nanoparticles solution was prepared using Au seed, significant changes in sizes and shapes of Au seed occurred. Spherical nanoparticles in the Au seed (22.2 mM) were completely changed to polygonal nanoparticles. The amount of mercury adsorbed using 9 ppm mercury solution on polygonal nanoparticles is higher (64.88%) than spherical nanoparticles (18.77%). Conclusion: These results indicated that mercury adsorption strongly depends on the sizes and shapes of Au nanoparticles. Polygonal nanoparticles adsorbed more mercury than spherical nanoparticles but the amount mercury adsorbed is inversely proportional to their size.