Nanoparticles (NPs) are the future of the chemistry and technology world. They have a variety of applications, ranging from environmental remediation to alternative energy. A common way to synthesize gold NPs is the Frens synthesis method. This synthesis involves a gold chloride solution being brought to a boil while undergoing reflux and adding a sodium citrate solution to the boiling gold solution to synthesize nanoparticles where a color change (from yellow to dark red/purple) is observed in the solution. The Frens synthesis is a good method for use in undergraduate laboratories because it combines practices that are taught early on in chemistry undergraduate education, such as preparing solutions, reflux techniques, and boiling practices. However, one downfall of the Frens synthesis is that 500mL of nanoparticles are synthesized. If each group or individual in the laboratory section at the time does their own Frens synthesis to yield the nanoparticles, there becomes a lot of chemical usage and chemical waste production. At Saint Francis University (SFU), green chemistry principles are taught and emphasized, so using a synthesis method that produces a lot of chemical waste is not ideal. In this research, the amount of reactants and products produced has been cut down to one quarter of what is originally stated; now, only 125mL of nanoparticles are synthesized. After analysis of the nanoparticles, it was found that the nanoparticles synthesized under the true method, a half reduction, and the quarter reduction all had the same shape and size, as demonstrated by the resultant ultra-violet visible spectroscopy, Dynamic Light Scattering, and Scanning Electron Microscopy data collected. This new procedure has significantly reduced the amount of chemicals that are used in the laboratory, while also reducing the amount of waste being produced; thus, less pollution is being released into the environment resulting from Frens nanoparticle synthesis. This new method aligns with the first principle of green chemistry, which is waste prevention.

Greener way to teach the Frens nanoparticle synthesis

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