Uranium mining for the nuclear industry causes immense environmental damage, which becomes more severe as reserves are depleted.
The isolation of uranium from seawater would be a much more environmentally friendly alternative. In the journal Angewandte Chemie, American researchers have now introduced a process by which they can produce tailored, highly effective adsorption agents to do this job.Because the concentration of uranyl ions in seawater is very low, adsorption agents used for this process must be particularly efficient. By carefully controlling the surface and pore structures, a team from Oak Ridge National Laboratory and the University of Tennessee has now been able to significantly increase both the rate and capacity of adsorption of a new polymer adsorbent.
The interiors of the resulting frameworks contain many accessible chloride species that then serve as starting points for the next polymerization step, which is known as atom-transfer radical polymerization (ATRP).This reaction allows the researchers to grow polyacrylonitrile chains within the framework. The advantage of ATRP is that the length of the chains is highly controllable and uniform. In the final step, the polyacrylonitrile is converted to polyamidoxime because amidoxime groups bind well to uranyl ions.
“These frameworks are the first example of ATRP initiators in which the initiator species is located within the nanoporous support network,” reports Dai. “This new process puts materials with tailored adsorption and surface properties within reach. The method can be used to produce a wide variety of polymer nanocomposites for applications including the removal of heavy-metal ions from solutions or novel catalysts.”
Title: Seawater Uranium Sorbents: Preparation from a Mesoporous Copolymer Initiator by Atom-Transfer Radical Polymerization
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201307825
Sheng Dai | Angewandte Chemie
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