(743b) Assessing the Selective Adsorption of Contaminants Using Spectroscopy and Chemometrics

The National Academy of Engineering has identified a global grand challenge for mankind is the accessibility of clean water for all human beings. Approaches for achieving this goal vary; however, one approach entails the use of carbon nanomaterials to remove contaminants from water systems. Carbon nanomaterials (e.g. graphene and carbon nanotubes) have been shown to provide a versatile means for achieving high uptake of organic, biological, and metallic materials from aqueous environments. A challenge with using carbon nanomaterials is tailoring them to selective removal of specific compounds. Given their strong non-covalent interactions, especially towards organic species, it can be difficult to assess the degree to which a specific compound has been removed from water systems containing multiple organic species. This is especially true when using spectroscopy techniques where contaminants have similar spectral signals. One alternative is to combine spectroscopy with chemometric analysis tools to discern between different species in the system. Parallel Factor Analysis (PARAFAC) provides the means to which multiple species can be identified when dealing with realistic water systems. In this study, the use of hybrid graphene/single wall carbon nanotube adsorbents towards the removal of organic compounds from natural water is assessed. These carbon nanomaterial adsorbent systems have already been shown to effectively remove 80-90% of organic contaminants from artificially contaminated water. Using natural water containing dissolved organic matter along with prevalent organic compounds (e.g. 2,4-dichlorophenoxyacetic acid), adsorption studies were completed to understand the removal uptake of these species. UV-Vis and multidimensional fluorescence spectroscopy were used to analyze the samples. PARAFAC was then utilized to assess which compounds were removed by the adsorbent. A discussion of the removal effectiveness of the prevalent compounds from natural water will be discussed.