Madhuleena Bhadra

A Bilayered Structure Comprised of Functionalized Carbon Nanotubes for Desalination by Membrane Distillation

The development of a novel carbon nanotube (CNT) immobilized membrane comprised of a double-layer structure is presented for water desalination by membrane distillation. The bilayered structure is comprised of CNTs functionalized with a hydrophobic octadecyl amine group on the feed side and carboxylated CNTs on the permeate side. The latter is more hydrophilic. The hydrophobic CNTs provide higher water vapor permeation, while the hydrophilic CNTs facilitate the condensation of water vapor. Together, these led to superior performance, and flux in a direct contact membrane distillation mode was found to be as high as 121 kg/m(2)h at 80 °C. The bilayered membrane represented an enhancement of 70% over the unmodified membrane and 37% over a membrane which had a monolayered structure where only the feed side was CNT-modified.

Advances in Nanostructured Membranes for Water Desalination

The availability of freshwater resources is dwindling in many parts of the world, a problem that is anticipated to grow with budding population. One promising source of potable water is the world’s virtually limitless supply of seawater, but so far desalination technologies have been too expensive for widespread use. With current advances in nanotechnology and the development of diverse nanomaterials, which can be employed for successful membrane fabrication, nanostructured membrane-based desalination might be ready for the next generation of breakthroughs. Typically, by facilitating the manipulation of matter and control of transport at nanometer length scales, fabrication of nanostructured membranes offers new opportunities to advance water desalination technologies. This chapter will provide a broad discussion on highly promising nanomaterials; their specific morphology, which leads to specific enhanced water permeation, membrane–vapor interactions, their membrane fabrication procedures, and potential applications in leading desalination technologies.