Robust carbon nanotube membranes directly grown on Hastelloy substrates and their potential application for membrane distillation

A new class of robust carbon nanotube (CNT) membranes is developed using a scalable chemical vapor deposition method by direct growth of the CNT on a nickel alloy (Hastelloy) mesh with micrometer-sized openings. The developed membranes have a dense, entangled network of CNT with 50-500 nm pore openings and are superhydrophobic. These CNT membranes are resistant to air oxidation up to ∼500 °C and chemical corrosion in concentrated HCl or NaCl solutions. Adhesion and ultrasonication tests suggest that the developed CNT membranes are resistant to delamination and demonstrate a high interfacial bonding of the grown CNT with the alloy substrate. Potential application of the developed CNT-Hastelloy membranes for separation is explored by conducting membrane distillation tests using a 10,000 mg/L NaCl solution. The developed membranes show similar salt rejection performance compared with a carbon bucky paper membrane. These robust carbon nanotube membranes are reusable and expected to be less susceptible to fouling because of their superhydrophobic properties. Furthermore, if fouled, they can be regenerated by heating in air or using an acid wash.