ABSTRACT
This chapter presents the applications of nanotechnology to materials resources. Besides the applications in extraction and pollution control maturing nanotechnology is likely to cause sweeping changes in the mix of desired materialsNanotechnology-related applications will probably increase the demand for certain rare elements. The extraction of solutes from aqueous solutions is basic to pollution control and purification, which are dearly not amenable to separation by thermally driven phase changes, but for which a number of membrane processes. The nanofabrication challenges for all semipermeable membranes are much as with superstrength materials: that is, the problem of building structures over macroscopic distances that remain defect-free at the molecular level. Conceptually solid semipermeable membranes also could be made "switchable," and indeed one group has reported electroswitchable transport of ions across a nanoporous membrane functionalized with redox-active groups. The chapter describes a number of prototype systems employing photoswitchable binding of a solute species.
