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

Abstract

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 utrasonication 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.

Triple-Layer Nanocomposite Membrane Prepared by Electrospinning Based on Modified PES with Carbon Nanotubes for Membrane Distillation Applications

“…One of the main techniques commonly used to enhance the membrane properties to be suitable for the MD process is blending with different nano-additives [18][19][20]. For example, the immense potential of carbon nanotubes (CNTs) as an additive has been a subject of interest to be used in the fabrication of the membranes [21,22]. Both single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) have been included in different polymeric membranes to enhance their hydrophobicity [23,24].…”

Characterization of Vertically Aligned Carbon Nanotube Forests Grown on Stainless Steel Surfaces

“…Modifying the synthesis conditions allows tuning of the geometry, alignment, density, and structure of CNTs, which offers control over their mechanical performance [5,6,7,8,9,10]. CNT forests grown directly on metal substrates, and specifically on steels, are particularly interesting because they offer a conformal coating solution, which is independent from the substrate’s geometry [11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36]. Direct growth avoids the need for intermediate adhesive layers, thus enabling a robust contact interface between the CNTs and the metal [12].…”

One millimeter per minute growth rates for single wall carbon nanotube forests enabled by porous metal substrates

“…Previous reports of the use of metal meshes with several surface treatments as substrates of CNT growth have shown the limited yields of multiwall carbon nanotubes (MWCNTs) by thermal chemical vapor deposition (CVD). [20][21][22][23][24][25][26] These MWCNTs were grown uniformity on the surface of mesh substrates regardless of shape and size (porosity, wire diameter, aperture, and surface area), which was attributed to the source gas contact to all catalysts on the mesh substrate. We used this as a positive conceptual proof that mesh could be used for high yield SWCNT synthesis.…”