Fast Water Transport through Subnanometer Diameter Vertically Aligned Carbon Nanotube Membranes

Abstract

Small-diameter carbon nanotubes (CNTs) have outstanding mass-transport properties, especially enhanced water flow. Here, we report on water transport through the first macroscopic membranes with vertically oriented, subnanometer (0.8 nm) CNT pores, made by a scalable, solution-based method with electric-field alignment of bulk-grown single-wall CNTs (SWCNTs). After plasma etching to open pores, vertically aligned CNTs served as the primary pathway for liquid-water transport. The CNT membranes showed fast pressure-driven water transport, with up to 10 5 -fold enhancement compared to no-slip Hagen−Poiseuille flow. Comparing 0.8 and 3 nm CNTs, we found that the hydrodynamic slip lengths increased with decreasing nanotube diameter, reaching 8.5 μm for the smaller-diameter CNTs. The results suggest that pressure-driven water transport in smalldiameter CNTs is increasingly dominated by entrance resistance, thus becoming independent of nanotube length. Scalably fabricated membranes incorporating vertically aligned subnanometer CNT pores could have applications in water filtration, desalination, and energy harvesting.

Electric Field‐induced Orientation of Carbon Nanomaterials in Dispersions

“…This work was the first time to systematically compared the orientation rules of the above three types of CNMs under different conditions, which provides a certain research basis for researchers to target various dimensions of other inorganic nanofillers. The study on the orientation of CNMs in solvents can be extended to the orientation of CNMs SWCNTs [c] AC EF [37] SWCNTs AC EF [40] GO [d] MF [e] [39] TEM GR AC EF ultra-thin sectioning of samples solid vacuum 5×10 3 -5×10 5 - [19] GR, CNTs AC EF [44] MWCNTs [f] AC EF [43] EOGO [g] AC EF [45] MWCNTs MS [h] [25]…”

Flow through Deformed Carbon Nanotubes Predicted by Rigid and Flexible Water Models

“…The large surface area-to-volume ratio inherent to the nanoscale plays a central role in the water transport properties. , From the experimental perspective, Qin et al observed that water velocity in carbon nanotubes (CNTs) decreases with increasing tube diameter; therefore, the obtained values ranged between 46 (1.6 nm) and 928 μ m/s (0.8 nm). Also, Secchi et al evaluated the fluid flow rate in nanochannels and observed that the slip length increases monotonically with the decrease in tube diameter.…”

Effect of terahertz electromagnetic field on single-file water transport through a carbon nanotube

“…1,2 The rapid conduction of single-file water chains in one-dimensional channels as well as the regular structure of quantized water layers in two-dimensional channels has sparked vast interest in research. 3,4 Hence, the investigation of water transportation mechanisms within nanochannels holds significance for fundamental scientific research and various industrial, biological, and medical applications. 5,6…”

“…1,2 The rapid conduction of single-file water chains in one-dimensional channels as well as the regular structure of quantized water layers in two-dimensional channels has sparked vast interest in research. 3,4 Hence, the investigation of water transportation mechanisms within nanochannels holds significance for fundamental scientific research and various industrial, biological, and medical applications. 5,6 Because of the structural simplicity of artificial carbon nanotubes (CNTs) compared to protein channels, they are often used as a prototype model for studying water and ion transport to mimic protein channels.…”