Advanced Materials for Environmental Control

该建议涉及设计和开发性能大大改善的全新类型的离子交换材料。 提出了两种不同的材料家族，即1）涂覆在玻璃纤维上的离子交换树脂和2）其中微孔表面用酸性或碱性基团官能化的活性碳纤维。 与市售的离子交换珠相比，纤维形式的使用预期提供10倍的交换和再生动力学改善。 关于离子交换纤维，研究将集中在两种类型的系统上。 第一类由涂覆在玻璃纤维基材上的阳离子和阴离子交换树脂组成。 关于目前可用的离子交换珠粒，应当克服的问题包括使渗透冲击效应最小化、消除珠粒制造中使用的对环境不友好的溶剂以及降低与使用昂贵的密封系统相关的成本。 待开发的第二类离子交换纤维是活性碳纤维和用阳离子或阴离子交换基团官能化的基材。 用于离子交换的活性炭系统的潜在益处是高的化学和热稳定性，这是聚合物树脂系统无法获得的。 活性炭还具有连续的微孔网络，其可以从6 A至28 A的尺寸定制。 这为设计具有更高选择性的离子交换/螯合系统提供了可能性。 一个有趣的研究将是溶胀的聚合物网络与非溶胀的微孔碳结构的扩散过程的比较。这些新的纤维应该允许去除金属污染物低于1 ppb。 特别强调的领域包括消除铅和汞等重金属、铯和锶等放射性废物以及砷酸盐（砷）地下水污染物。

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.