Chitin-based sorbents have been developed by our group as biodegradable extractants for harvesting uranium from seawater. However, for these materials to be usable, a balance must be obtained between their shorter lifetime in the marine environment and the performance needs for their application. We are investigating the use coextraction of biocidal copper(II) ions naturally present in seawater along with uranium as one possible route to slowing down the biodegradation of the sorbent.<br/><br/>Native chitin (poly(N-acetylglucosamine)) can be extracted from biomass by dissolution in ionic liquids such as 1-ethyl-3-methylimidazolium acetate and formed into usable materials such as fibers and films. Once precipitated from the IL, these materials are insoluble in most other solvents and can be exposed to solutions of reactive chemicals to selectively functionalize only the exposed surface molecules. Deacetylation of chitin by sodium hydroxide gives glucosamine, which has a basic amino group which should show high affinity for early transition metals such as copper. The amino group can also be used as a nucleophile to tether a uranium selective functional group, such as amidoxime, to the chitin backbone. The functional groups can be segregated by joining two separately functionalized resins or dispersed randomly amongst each other by varying the exposure time of the deacetylated chitin to further treatment. Here we present the preparation and characterization of these materials, solution studies on their affinity for copper(II) and uranyl ions, and the characterization of metals bound to the sorbent surface.

Dual functional chitin based sorbents for coextraction of aqueous copper and uranium

249th National Meeting (2015)

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