Separate groups of researchers in the U.K. and Japan are working on nano-based filtration technologies that use various carbon forms to manipulate water permeation. Both groups, however, are still developing practical functions for the technology, said Donald R. Paul, chemical engineer at the University of Texas at Austin. Both technologies "are clearly early-stage research and should stimulate further work. ... The real trick will be to make them on a large enough scale, and cheap enough, to be useful in packaged modules," Paul said.