Membranes of Vertically Aligned Superlong Carbon Nanotubes

Abstract

In the present work, we have developed a simple but effective method to prepare superlong vertically aligned carbon nanotubes (SLVA-CNT) and epoxy composite membranes, and we have demonstrated that various liquids, including water, hexane, and dodecane, can effectively pass through the SLVA-CNT membranes. These results were confirmed by molecular dynamics simulations. While the mechanical densification was used to further enhance the flow transport through the SLVA-CNT membranes, we developed in this study a magnetic-nanoparticle switching system to turn on and off the flow through the nanotube membrane by simply applying an alternating voltage. The methodologies developed in this study should have a significant implication to the development of various smart membranes for advanced intelligent systems.

A carbon nanotube wall membrane for water treatment

“…The water permeability through the outer-wall CNT membrane with a D f of 10 before and after the thermal purification of CNTs is shown in Fig. 2, along with the water permeabilities reported in the literature for other CNT membranes [1][2][3]5 . The water permeability of the outer-wall membrane is observed to have more than double as a result of the heat treatment due to the corresponding increase in the water flow velocity (Table 1).…”

“…However, the water permeance through CNT membranes [1][2][3] was initially not considerably different from that attainable using a commercial polysulfone (PSf) ultrafiltration (UF) membrane 11 , which is approximately several hundred litres per square metre per hour (LMH bar À 1 ). Only recently has a water permeability of 2,400 LMH bar À 1 been achieved 11 .…”

“…This vertically aligned CNT membrane with opened CNT tips, known as an open-ended CNT membrane, has since been used in water treatment applications 2,3 . At approximately the same time, another type of CNT membrane was introduced 4 , in which the interstices between nanotubes in a vertical array of CNTs were utilized as membrane pores; this membrane is known as an outerwall CNT membrane 5,6 .…”

Enhanced hydrogen separation by vertically-aligned carbon nanotube membranes with zeolite imidazolate frameworks as a selective layer

“…Herein, the dense membranes were fabricated by filling the VACNT arrays with epoxy, similar to the reported route to fill the super long VACNT arrays. 19,22 The typical cross-section and surface morphologies of the VACNT membrane are shown in Fig. 2.…”

“…22 Before testing, the gas line and the cell were purged with target gas from the cylinder and evacuated several times. The membrane was glued on a porous stainless steel support (porosity .…”