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Carbon nanotubes hold significant potential for developing highly efficient desalination membranes. However, achieving both enhanced water transfer rate and salt rejection efficiency simultaneously has been challenging due to the pore size limitation. In this study, we discovered that embedding a carbon nanotube within a large-diameter carbon nanotube enables the simultaneous enhancement of both water transfer rate and salt rejection efficiency. This outcome is attributed to the accelerated water velocity and the blockage of ions entering the narrowed cross-section of the carbon nanotube. These findings have valuable implications for the design of fast water transport membranes with high salt rejection efficiency. [Display omitted] • The water and ion transfer are well-tuned by the embedded carbon nanotube. • The enhancement of both water transfer and salt rejection efficiency is achieved. • The water transfer and the blockage of ions affect the salt rejection rate. [ABSTRACT FROM AUTHOR]

Thermal fluctuations can significantly slow down water transfer rate, and result in low unidirectional transport efficiency. However, in this study, we employ molecular dynamics simulations to investigate water transport in nanochannels with large diameters. Surprisingly, we discover that the insertion of an inner embedded nanochannel unexpectedly enhances water transfer rate through the nanochannels. We attribute this enhancement to the increased water velocity, which occurs due to the decrease in the cross-section of the nanochannel upon inserting an inner nanochannel. These findings have important implications for optimizing water transport in nanochannels with large diameters. [Display omitted] • A large nanochannel inserted an inner embedded nanochannel enhances water transport. • The inner embedded nanochannel increases water unidirectional transport efficiency. • Water phase in the multiple nanochannel changes differently. [ABSTRACT FROM AUTHOR]

The structure of the carbon nanotube affects water transport greatly. However, there is little understanding of water transport through the inward combined carbon nanotube. Molecular dynamics simulations are adopted to investigate the properties of water molecules through the inward combined carbon nanotube in this article. We find that water unidirectional transport efficiency increases in the inward combined carbon nanotube unless water molecules cannot pass through the inward combined carbon nanotube. The occupancy of water molecules, the bidirectional water transfer rate, the unidirectional water transfer rate, the velocity, and the order parameter of water molecules in the inward carbon nanotube are dependent on the structure of the inward combined carbon nanotube. Our results pave the way for understanding the inward combined structure effect on the transport of water molecules. [ABSTRACT FROM AUTHOR]

The lateral electric field affects a single-file water molecules transport through a disjoint carbon nanotube (DCNT). Nevertheless, it is not clear whether this phenomenon still exists when the diameter of the DCNT gradually increases. Herein, we use molecular dynamics simulations to investigate the transport of water molecules through the DCNTs with different diameters under the influence of the lateral electric fields. We find that the occupancy of water molecules, the flow rate and the flux rate within the large DCNTs decrease greatly when the lateral electric field increases from 0 V/nm to 1.0 V/nm, whereas the occupancy of water molecules, the flow rate and the flux rate within the small DCNTs decrease slightly when the lateral electric field increases from 0 V/nm to 1.0 V/nm. Our results are beneficial to understand the diameter effect of the DCNT on water transport and design novel nanoscale devices. [ABSTRACT FROM AUTHOR]

Water transport within short carbon nanotubes is bidirectional if no pressure difference, mechanical force or electric field is applied on water molecules in the simulations. Tuning the behavior of water bidirectional transport in nanoscale is of importance for applications. In this article, we find that the pressure difference and the electric field play important roles in accelerating water unidirectional transport efficiency through carbon nanotubes. Our findings are beneficial to understand water transport within short carbon nanotubes under the influence of the pressure difference and the electric field in nanoscale. [Display omitted] • The unidirectional water transport has rarely beed studied. • The size of the nanochannel affects the unidirectional water transport efficiency. • The electric field enhances the unidirectional water transport efficiency. [ABSTRACT FROM AUTHOR]

Driving methane out of a nanochannel efficiently is important for methane accumulation. In this article, we investigate the occupancy and the transport properties of a methane-water mixture in a carbon nanotube using molecular dynamics simulations under the influence of an electric field. The strength and the direction of the electric field affect the occupancy and the transport order in the carbon nanotube. Once the carbon nanotube is filled with methane (or water) molecules, the transfer of the other molecules is blocked. The adsorption process of methane or water molecules in the carbon nanotube is reversible by opening or closing the electric field. Our findings are beneficial for the tunable transport in a nanochannel. [ABSTRACT FROM AUTHOR]

[Display omitted] • Water transfer through the single-walled carbon nanotube with a small nanogap under a vertical electric field is investigated firstly. • Water properties change sharply in the single-walled carbon nanotube with a large nanogap under a strong electric field. • The mobility of water molecules in the single-walled carbon nanotube with a small nanogap is discussed. Water transport through a single-walled carbon nanotube (SWCNT) with a small nanogap under a vertical electric field is studied by molecular dynamics simulations. Water transfer rate, water adsorption, water mobility and water orientation in the SWCNT with a nanogap decrease faster than that in the SWCNT without a nanogap with increasing the vertical electric field. The vertical electric field affects water properties by affecting the formation of a water bridge in the nanogap region. Our results are beneficial to design the energy-saving devices. [ABSTRACT FROM AUTHOR]

Water transport through a disjoint nanochannel is important for understanding water molecules confined in a complex nanostructure. However, the transport behavior of water molecules in the disjoint nanochannel is affected by the nanogap of the disjoint nanochannel greatly. It is still difficult to transfer water molecules through the disjoint nanochannel with a large nanogap even under high pressure. In this article, we report water transfer properties through a disjoint nanochannel with a large nanogap under the influence of an electric field. By the aid of the electric field, the efficiency of water transfer through a (10, 0) disjoint nanochannel is enhanced sharply. The transfer of water molecules through a (12, 0) disjoint nanochannel and a (14, 0) disjoint nanochannel increases under an appropriate electric field but decreases under a strong electric field. Our findings are beneficial to achieve a stable and fast water transport through a disjoint nanochannel. • Water transfer rate thought a (10, 0) disjoint nanochannel with a large nanogap can be enhanced greatly. • The transfer of water molecules through a (12, 0) disjoint nanochannel and a (14, 0) disjoint nanochannel increases under an appropriate electric field but decreases under a strong electric field. [ABSTRACT FROM AUTHOR]