Synthesis of Iron Nanoparticles in Aqueous and Nonaqueous Solutions and Their Use in Simulated Waste Remediation: An Experiment for First-Year College Students

摘要

Iron nanoparticles are used to remove pollutants from soil and water in the environment and from industrial waste streams. A laboratory experiment described here is based on this application of nanotechnology. The procedure is appropriate for first-year undergraduate students with some background in general chemistry. Students synthesize iron nanoparticles via borohydride reduction of iron(III) chloride. Following this, students perform a series of reactions in which iron nanoparticles or bulk iron powders react with an aqueous dye. Periodic measurements of the absorbance in the visible spectrum show the decline in dye concentration. Students can analyze their results several different ways. The nanoparticles consume orders of magnitude more dye per gram of iron than the bulk powders due to their greater surface area. On the other hand, economic considerations make the bulk iron a more appealing choice. This dichotomy can lead to an interesting discussion among students about the apparent value of nanotechnology for environmental remediation. A modified version of the experiment is described in which the chemical reaction between a dye and iron particles occurs within a nonaqueous solvent. This procedure is more similar to the actual method used for removing organic pollutants from soil and ground water.