The surface area of materials can play an important role in many applications.   However, surface areas of nanoscale materials are measured with instruments not typically found in the undergraduate lab.   Therefore, surface area is frequently not explored except when comparing two bulk scale materials.   The purpose of this work was to develop a laboratory experiment to investigate surface area of nanoscale materials without the need for specialized instrumentation. The experiment utilizes the adsorption of methyl orange on high surface area magnesium oxide.   MgO samples ranging from 30 to 150 m<sup>2</sup>/g were synthesized and their surface areas were measured by mixing the sample in a dye solution and monitoring the adsorption by UV/Vis absorbance at 464 nm.  As the mixing time increased, the dye concentration in solution decreased due to adsorption onto the MgO surface. Higher surface area MgO adsorbed more methyl orange dye, which lead to a lower absorbance. The experimental results were compared to the surface areas measured by nitrogen physisorption at 77K. The results show that dye adsorption is an effective method to measure surface areas of some nanoscale materials and allows for an easy experiment to explore an important topic in chemistry. <br/>

Undergraduate laboratory experiment to investigate surface areas of nanoscale materials

251st National Meeting (2016)

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