Multiscale simulation of water flow through laboratory-scale nanotube membranes

Borg, Matthew K.; Lockerby, Duncan A.; Ritos, Konstantinos; Reese, Jason M.

doi:10.1016/j.memsci.2018.08.049

Cited by 58 publications

(80 citation statements)

References 35 publications

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“…A significant discrepancy can be seen between the enhancement factors quoted by Du et al [12] (light green square) and Zhang et al [38] (red square) for the 10 nm diameter experiments. It has been suggested that the extremely large enhancement values reported by Majumder et al (dark green squares) and Du et al (light green squares) represent an over-estimation [39] and could be the result of an uncontrolled external variable such as an electric field [40]. In general, experiments involving flow through CNT membranes are prone to showing errors due to practical challenges in 4 as blue filled circles joined by straight line segments.…”

Section: Discussion and Comparison With Experimental Datamentioning

confidence: 99%

Investigating enhanced mass flow rates in pressure-driven liquid flows in nanotubes

2019

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Over the past two decades, several researchers have presented experimental data from pressure-driven liquid flows through nanotubes. They quote flow velocities which are four to five orders of magnitude higher than those predicted by the classical theory. Thus far, attempts to explain these enhanced mass flow rates at the nanoscale have focused mainly on introducing wall-slip boundary conditions on the fluid mass velocity. In this paper, we present a different theory. A change of variable on the velocity field within the classical Navier-Stokes equations is adopted to transform the equations into physically different equations. The resulting equations, termed re-casted Navier-Stokes equations, contain additional diffusion terms whose expressions depend upon the driving mechanism. The new equations are then solved for the pressure driven flow in a long nano-channel. Analogous to previous studies of gas flows in micro-and nano-channels, a perturbation expansion in the aspect ratio allows for the construction of a 2D analytical solution. In contrast to slip-flow models, this solution is specified by a no-slip boundary condition at the channel walls. The mass flow rate can be calculated explicitly and compared to available data. We conclude that the new re-casting methodology may provide an alternative theoretical physical explanation of the enhanced mass flow phenomena.

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Section: Discussion and Comparison With Experimental Datamentioning

confidence: 99%

Investigating enhanced mass flow rates in pressure-driven liquid flows in nanotubes

2019

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“…Error bars represent the standard deviation of three membranes. d) Pure water enhancement factors in CNTs from literature experiments (data points) [3,15,21,[38][39][40] and simulations (lines) [11,13,[41][42][43] compared to our results for a 60 cm 2 SWCNT membrane. Error bar for this work represents the standard deviation of four membranes (both small and large) and is smaller than the data point.…”

Section: Doi: 101002/advs202001670mentioning

confidence: 97%

Ultra‐Permeable Single‐Walled Carbon Nanotube Membranes with Exceptional Performance at Scale

et al. 2020

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Enhanced fluid transport in single-walled carbon nanotubes (SWCNTs) promises to enable major advancements in many membrane applications, from efficient water purification to next-generation protective garments. Practical realization of these advancements is hampered by the challenges of fabricating large-area, defect-free membranes containing a high density of open, small diameter SWCNT pores. Here, large-scale (≈60 cm 2) nanocomposite membranes comprising of an ultrahigh density (1.89 × 10 12 tubes cm −2) of 1.7 nm SWCNTs as sole transport pathways are demonstrated. Complete opening of all conducting nanotubes in the composite enables unprecedented accuracy in quantifying the enhancement of pressure-driven transport for both gases (>290× Knudsen prediction) and liquids (6100× no-slip Hagen-Poiseuille prediction). Achieved water permeances (>200 L m −2 h −1 bar −1) greatly exceed those of state-of-the-art commercial nano-and ultrafiltration membranes of similar pore size. Fabricated membranes reject nanometer-sized molecules, permit fractionation of dyes from concentrated salt solutions, and exhibit excellent chemical resistance. Altogether, these SWCNT membranes offer new opportunities for energy-efficient nano-and ultrafiltration processes in chemically demanding environments. Carbon nanotubes (CNTs) have garnered sustained interest in many areas of material science due to their outstanding thermal, mechanical, electrical, and fluidic properties and have enabled advancements in a variety of functional materials and technologies. [1,2] In separation applications, CNTs are interesting membrane building blocks as their unique transport properties lead to exceptionally large flow rates compared to conventional porous materials with commensurate pore sizes.

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“…where J int is calculated empirically from dV dt as was described above, while J PTP k × ΔP, and k is the parameter defined by the geometry of the pore (Borg et al, 2018). J PTP is proportional to ΔP that is equal to the oncotic pressure.…”

Section: Calculation Of Water Flux Rates Based On Shrinkage and Estimmentioning

confidence: 99%

The very low number of calcium-induced permeability transition pores in the single mitochondrion

Neginskaya

Strubbe

Amodeo

et al. 2020

Journal of General Physiology

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Mitochondrial permeability transition (PT) is a phenomenon of stress-induced increase in nonspecific permeability of the mitochondrial inner membrane that leads to disruption of oxidative phosphorylation and cell death. Quantitative measurement of the membrane permeability increase during PT is critically important for understanding the PT’s impact on mitochondrial function. The elementary unit of PT is a PT pore (PTP), a single channel presumably formed by either ATP synthase or adenine nucleotide translocator (ANT). It is not known how many channels are open in a single mitochondrion during PT, which makes it difficult to quantitatively estimate the overall degree of membrane permeability. Here, we used wide-field microscopy to record mitochondrial swelling and quantitatively measure rates of single-mitochondrion volume increase during PT-induced high-amplitude swelling. PT was quantified by calculating the rates of water flux responsible for measured volume changes. The total water flux through the mitochondrial membrane of a single mitochondrion during PT was in the range of (2.5 ± 0.4) × 10−17 kg/s for swelling in 2 mM Ca2+ and (1.1 ± 0.2) × 10−17 kg/s for swelling in 200 µM Ca2+. Under these experimental conditions, a single PTP channel with ionic conductance of 1.5 nS could allow passage of water at the rate of 0.65 × 10−17 kg/s. Thus, we estimate the integral ionic conductance of the whole mitochondrion during PT to be 5.9 ± 0.9 nS for 2 mM concentration of Ca2+ and 2.6 ± 0.4 nS for 200 µM of Ca2+. The number of PTPs per mitochondrion ranged from one to nine. Due to the uncertainties in PTP structure and model parameters, PTP count results may be slightly underestimated. However, taking into account that each mitochondrion has ∼15,000 copies of ATP synthases and ANTs, our data imply that PTP activation is a rare event that occurs only in a small subpopulation of these proteins.

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Multiscale simulation of water flow through laboratory-scale nanotube membranes

Cited by 58 publications

References 35 publications

Investigating enhanced mass flow rates in pressure-driven liquid flows in nanotubes

Investigating enhanced mass flow rates in pressure-driven liquid flows in nanotubes

Ultra‐Permeable Single‐Walled Carbon Nanotube Membranes with Exceptional Performance at Scale

The very low number of calcium-induced permeability transition pores in the single mitochondrion

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