Advanced Materials for Environmental Control

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This proposal is concerned with the design and development of completely new kinds of ion exchange materials with greatly improved properties. Two distinct families of materials are proposed, namely 1) ion exchange resins coated on glass fibers and 2) activated carbon fibers where the surfaces of the micropores are functionalized with acidic or basic groups. The use of a fiber form is expected to provide a 10x improvement in kinetics of exchange and regeneration as compared to the commercially available ion exchange beads. With respect to ion exchange fibers, research will focus on two types of systems. The first family consists of cationic and anionic exchange resins coated on glass fiber substrates. Problems that should be overcome with respect to currently available ion exchange beads include minimizing osmotic shock effects, elimination of environmentally unfriendly solvents used in bead manufacture, and reducing the costs associated with the use of expensive containment systems. The second family of ion exchange fibers to be explored is activated carbon fibers and substrates functionalized with cationic or anionic exchange groups. Potential benefits of an activated carbon system for ion exchange are high chemical and thermal stability, which cannot be attained by polymeric resin systems. Activated carbon also has a continuous microporous network which can be tailored from dimensions of 6 A to 28 A. This provides the potential for designing ion exchange/chelating systems with even more selective properties. An interesting study will be a comparison of the diffusional processes of swollen polymeric networks versus a non-swelling microporous carbon structure.These new fibers should permit removal of metal contaminants to below 1ppb. Areas of particular emphasis include eliminating heavy metals such as lead and mercury, radioactive wastes such as cesium and strontium, and arsenate(ite) ground water contaminants.