Characterization and evaluation of carbon nanotube Bucky-Paper membranes for direct contact membrane distillation

Self-supporting carbon nanotube (CNT) Bucky-Papers have unique structural and surface properties which can be utilised in many applications. In this work we characterised pure self-supporting CNT membranes, where CNTs were held together only by Van der Waals forces, and evaluated their potential and performance in direct contact membrane distillation. The membranes were found to be highly hydrophobic (contact angle of 113°), highly porous (90%), and to exhibit a thermal conductivity of 2.7 kW/m2 h. We demonstrate, as a proof of concept, that self-supporting CNT Bucky-Paper membranes can be used for desalination in a direct contact membrane distillation setup with 99% salt rejection and a flux rate of ∼12 kg/m2 h at a water vapour partial pressure difference of 22.7 kPa. Ageing of the membranes by delamination is a main factor limiting their performance and work is currently under way to address this issue by investigating composite material structures.