Recent Advances in Applications of Carbon Nanotubes for Desalination: A Review

As a sustainable, cost-effective and energy-efficient method, membranes are becoming a progressively vital technique to solve the problem of the scarcity of freshwater resources. With these critical advantages, carbon nanotubes (CNTs) have great potential for membrane desalination given their high aspect ratio, large surface area, high mechanical strength and chemical robustness. In recent years, the CNT membrane field has progressed enormously with applications in water desalination. The latest theoretical and experimental developments on the desalination of CNT membranes, including vertically aligned CNT (VACNT) membranes, composited CNT membranes, and their applications are timely and comprehensively reviewed in this manuscript. The mechanisms and effects of CNT membranes used in water desalination where they offer the advantages are also examined. Finally, a summary and outlook are further put forward on the scientific opportunities and major technological challenges in this field.

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Diffusion of dilute gas in arrays of randomly distributed, vertically aligned, high-aspect-ratio cylinders

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.8.7 ◽

2017 ◽

Vol 8 ◽

pp. 64-73 ◽

Cited By ~ 3

Author(s):

Wojciech Szmyt ◽

Carlos Guerra ◽

Ivo Utke

Keyword(s):

Carbon Nanotubes ◽

Diffusion Coefficient ◽

Aspect Ratio ◽

High Aspect Ratio ◽

Gas Transport ◽

Gas Diffusion ◽

Vertically Aligned Carbon Nanotubes ◽

Dilute Gas ◽

Aligned Carbon Nanotubes ◽

Vertically Aligned

In this work we modelled the diffusive transport of a dilute gas along arrays of randomly distributed, vertically aligned nanocylinders (nanotubes or nanowires) as opposed to gas diffusion in long pores, which is described by the well-known Knudsen theory. Analytical expressions for (i) the gas diffusion coefficient inside such arrays, (ii) the time between collisions of molecules with the nanocylinder walls (mean time of flight), (iii) the surface impingement rate, and (iv) the Knudsen number of such a system were rigidly derived based on a random-walk model of a molecule that undergoes memoryless, diffusive reflections from nanocylinder walls assuming the molecular regime of gas transport. It can be specifically shown that the gas diffusion coefficient inside such arrays is inversely proportional to the areal density of cylinders and their mean diameter. An example calculation of a diffusion coefficient is delivered for a system of titanium isopropoxide molecules diffusing between vertically aligned carbon nanotubes. Our findings are important for the correct modelling and optimisation of gas-based deposition techniques, such as atomic layer deposition or chemical vapour deposition, frequently used for surface functionalisation of high-aspect-ratio nanocylinder arrays in solar cells and energy storage applications. Furthermore, gas sensing devices with high-aspect-ratio nanocylinder arrays and the growth of vertically aligned carbon nanotubes need the fundamental understanding and precise modelling of gas transport to optimise such processes.

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Boehmite Nanofibers as a Dispersant for Nanotubes in an Aqueous Sol

10.26434/chemrxiv.6652955.v1 ◽

2018 ◽

Author(s):

Gen Hayase

Keyword(s):

Carbon Nanotubes ◽

Aspect Ratio ◽

Aqueous Solutions ◽

High Aspect Ratio ◽

Multiwall Carbon Nanotubes ◽

Multiwall Carbon ◽

Nanotube Films

By exploiting the dispersibility and rigidity of boehmite nanofibers (BNFs) with a high aspect ratio of 4 nm in diameter and several micrometers in length, multiwall-carbon nanotubes (MWCNTs) were successfully dispersed in aqueous solutions. In these sols, the MWCNTs were dispersed at a ratio of about 5–8% relative to BNFs. Self-standing BNF–nanotube films were also obtained by filtering these dispersions and showing their functionality. These films can be expected to be applied to sensing materials.

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Dependence of Young’s modulus of vertically aligned carbon nanotubes on their aspect ratio

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/443/1/012010 ◽

2018 ◽

Vol 443 ◽

pp. 012010

Author(s):

M V Il’ina ◽

O I Il’in ◽

A A Konshin ◽

A A Fedotov ◽

O A Ageev

Keyword(s):

Carbon Nanotubes ◽

Aspect Ratio ◽

Young’S Modulus ◽

Young's Modulus ◽

Vertically Aligned Carbon Nanotubes ◽

Aligned Carbon Nanotubes ◽

Vertically Aligned

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Functionalization and Tip-open of Carbon Nanotubes for High-Performance Symmetric Supercapacitor

Dalton Transactions ◽

10.1039/d1dt02055b ◽

2021 ◽

Author(s):

Yaxiong Zhang ◽

Erqing Xie

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Aspect Ratio ◽

Specific Surface ◽

Surface Area ◽

Chemical Stability ◽

High Aspect Ratio ◽

High Performance ◽

Large Specific Surface Area ◽

Symmetric Supercapacitor

Carbon nanotubes (CNTs) have been widely studied as supercapacitor electrodes because of their excellent conductivity, high aspect ratio, excellent mechanical properties, chemical stability, and large specific surface area. However, the...

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Engineering the Surface and Mechanical Properties of Water Desalination Membranes Using Ultralong Carbon Nanotubes

Membranes ◽

10.3390/membranes8040106 ◽

2018 ◽

Vol 8 (4) ◽

pp. 106 ◽

Cited By ~ 5

Author(s):

Yehia M. Manawi ◽

Kui Wang ◽

Viktor Kochkodan ◽

Daniel J. Johnson ◽

Muataz A. Atieh ◽

...

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Aspect Ratio ◽

Water Flux ◽

Contact Angles ◽

Water Desalination ◽

Membrane Properties ◽

Porous Membranes ◽

Water Contact ◽

And Performance

In this work, novel polysulphone (PS) porous membranes for water desalination, incorporated with commercial and produced carbon nanotubes (CNT), were fabricated and analyzed. It was demonstrated that changing the main characteristics of CNT (e.g., loading in the dope solutions, aspect ratio, and functionality) significantly affected the membrane properties and performance including porosity, water flux, and mechanical and surface properties. The water flux of the fabricated membranes increased considerably (up to 20 times) along with the increase in CNT loading. Conversely, yield stress and Young’s modulus of the membranes dropped with the increase in the CNT loading mainly due to porosity increase. It was shown that the elongation at fracture for PS/0.25 wt. % CNT membrane was much higher than for pristine PS membrane due to enhanced compatibility of commercial CNTs with PS matrix. More pronounced effect on membrane’s mechanical properties was observed due to compatibility of CNTs with PS matrix when compared to other factors (i.e., changes in the CNT aspect ratio). The water contact angle for PS membranes incorporated with commercial CNT sharply decreased from 73° to 53° (membrane hydrophilization) for membranes with 0.1 and 1.0 wt. % of CNTs, while for the same loading of produced CNTs the water contact angles for the membrane samples increased from 66° to 72°. The obtained results show that complex interplay of various factors such as: loading of CNT in the dope solutions, aspect ratio, and functionality of CNT. These features can be used to engineer membranes with desired properties and performance.

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Catalytic Synthesis of High Aspect Ratio Al2O3 Impregnated Carbon Nanotubes Used to Improve Thermophysical Properties of Nanofluids with A Case Study on an Industrial Gasoline-water Heat Exchanger

Materials Express ◽

10.1166/mex.2019.1477 ◽

2019 ◽

Vol 9 (2) ◽

pp. 85-98

Author(s):

Zuhair Omar Malaibari

Keyword(s):

Carbon Nanotubes ◽

Heat Exchanger ◽

Aspect Ratio ◽

Thermophysical Properties ◽

High Aspect Ratio ◽

Catalytic Synthesis

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Advances in Halloysite Nanotubes–Polysaccharide Nanocomposite Preparation and Applications

Polymers ◽

10.3390/polym11060987 ◽

2019 ◽

Vol 11 (6) ◽

pp. 987 ◽

Cited By ~ 5

Author(s):

Yang Wu ◽

Yongzhi Zhang ◽

Junping Ju ◽

Hao Yan ◽

Xiaoyu Huang ◽

...

Keyword(s):

Wastewater Treatment ◽

Aspect Ratio ◽

Mechanical Strength ◽

Recent Progress ◽

Halloysite Nanotubes ◽

Large Aspect Ratio ◽

Swelling Properties ◽

High Mechanical Strength ◽

Practical Applications ◽

Treatment Application

Halloysite nanotubes (HNTs), novel 1D natural materials with a unique tubular nanostructure, large aspect ratio, biocompatibility, and high mechanical strength, are promising nanofillers to improve the properties of polymers. In this review, we summarize the recent progress toward the development of polysaccharide-HNTs composites, paying attention to the main existence forms and wastewater treatment application particularly. The purification of HNTs and fabrication of the composites are discussed first. Polysaccharides, such as alginate, chitosan, starch, and cellulose, reinforced with HNTs show improved mechanical, thermal, and swelling properties. Finally, we summarize the unique characteristics of polysaccharide-HNTs composites and review the recent development of the practical applications.

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