Characterization of a support-free carbon nanotube-microporous membrane for water and wastewater filtration

Thamaraiselvan, Chidambaram; Lerman, Sofia; Weinfeld-Cohen, Kamira; Dosoretz, Carlos G.

doi:10.1016/j.seppur.2018.03.038

Cited by 31 publications

(10 citation statements)

References 37 publications

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“…CNT textiles have already shown great potential in various applications such as water and air filtration, oil–water separation, and ballistic protection as well as lightweight current collectors of electric double-layer capacitors and lithium ion batteries. , Nonetheless, optimization of the alignment process via external AC electric fields can dramatically enhance the properties of the high aspect ratio (∼10 4 ) CNT-based textiles without sacrificing the efficiency and cost-effectiveness of the FCCVD process. Enhancing the tenacity of CNT textiles to values on par with standard carbon fibers (CFs; ∼2 N tex –1 ) would enable the adoption of CNT fibers in place of CF.…”

Section: Discussionmentioning

confidence: 99%

Highly Oriented Direct-Spun Carbon Nanotube Textiles Aligned by In Situ Radio-Frequency Fields

et al. 2022

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Carbon nanotubes (CNTs) individually exhibit exceptional physical properties, surpassing state-of-the-art bulk materials, but are used commercially primarily as additives rather than as a standalone macroscopic product. This limited use of bulk CNT materials results from the inability to harness the superb nanoscale properties of individual CNTs into macroscopic materials. CNT alignment within a textile has been proven as a critical contributor to narrow this gap. Here, we report the development of an altered direct CNT spinning method based on the floating catalyst chemical vapor deposition process, which directly interacts with the self-assembly of the CNT bundles in the gas phase. The setup is designed to apply an AC electric field to continuously align the CNTs in situ during the formation of CNT bundles and subsequent aerogel. A mesoscale CNT model developed to simulate the alignment process has shed light on the need to employ AC rather than DC fields based on a CNT stiffening effect (z-pinch) induced by a Lorentz force. The AC-aligned synthesis enables a means to control CNT bundle diameters, which broadened from 16 to 25 nm. The resulting bulk CNT textiles demonstrated an increase in the specific electrical and tensile properties (up to 90 and 460%, respectively) without modifying the quantity or quality of the CNTs, as verified by thermogravimetric analysis and Raman spectroscopy, respectively. The enhanced properties were correlated to the degree of CNT alignment within the textile as quantified by small-angle X-ray scattering and scanning electron microscopy image analysis. Clear alignment (orientational order parameter = 0.5) was achieved relative to the pristine material (orientational order parameter = 0.19) at applied field intensities in the range of 0.5–1 kV cm –1 at a frequency of 13.56 MHz.

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Section: Discussionmentioning

confidence: 99%

Highly Oriented Direct-Spun Carbon Nanotube Textiles Aligned by In Situ Radio-Frequency Fields

et al. 2022

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“…Its unique carbon atom hexagon array and p-p interaction offer large numbers of physical adsorption sites for Hg(II). 42,43 Aerogels materials, in addition, can give assistance to physical adsorption through 3D crosslinking structured network. 44 Porous structured materials are ideal candidates for heavy metal Hg(II) removal because they have large surface area and ne pore structure.…”

Section: Physical Adsorption For Hg(ii) Removalmentioning

confidence: 99%

Removal of Hg(ii) in aqueous solutions through physical and chemical adsorption principles

Xia

Chen

et al. 2019

RSC Adv.

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“…CNT fibers were fabricated by direct spinning from chemical vapor deposition (CVD) synthesis using a liquid source of carbon and an iron nanocatalyst, as described by Li et al (2004). The molecular weight cut off the membranes is in the tight ultrafiltration range (Thamaraiselvan et al, 2017). Their structure provides the CNT membrane with high strength, increased thermal stability (up to 400℃), wide chemical resistance, high permeability and high electric conductivity (≥40,000 S/m).…”

Section: Membranesmentioning

confidence: 99%

Low voltage electric potential as a driving force to hinder biofouling in self-supporting carbon nanotube membranes

et al. 2018

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This study aimed at evaluating the contribution of low voltage electric field, both alternating (AC) and direct (DC) currents, on the prevention of bacterial attachment and cell inactivation to highly electrically conductive self-supporting carbon nanotubes (CNT) membranes at conditions which encourage biofilm formation. A mutant strain of Pseudomonas putida S12 was used a model bacterium and either capacitive or resistive electrical circuits and two flow regimes, flow-through and cross-flow filtration, were studied. Major emphasis was placed on AC due to its ability of repulsing and inactivating bacteria. AC voltage at 1.5 V, 1 kHz frequency and wave pulse above offset (+0.45) with 100Ω external resistance on the ground side prevented almost completely attachment of bacteria (>98.5%) with concomitant high inactivation (95.3 ± 2.5%) in flow-through regime. AC resulted more effective than DC, both in terms of biofouling reduction compared to cathodic DC and in terms of cell inactivation compared to anodic DC. Although similar trends were observed, a net reduced extent of prevention of bacterial attachment and inactivation was observed in filtration as compared to flow-through regime, which is mainly attributed to the permeate drag force, also supported by theoretical calculations in DC in capacitive mode. Electrochemical impedance spectroscopy analysis suggests a pure resistor behavior in resistance mode compared to involvement of redox reactions in capacitance mode, as source for bacteria detachment and inactivation. Although further optimization is required, electrically polarized CNT membranes offer a viable antibiofouling strategy to hinder biofouling and simplify membrane care during filtration.

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Characterization of a support-free carbon nanotube-microporous membrane for water and wastewater filtration

Cited by 31 publications

References 37 publications

Highly Oriented Direct-Spun Carbon Nanotube Textiles Aligned by In Situ Radio-Frequency Fields

Highly Oriented Direct-Spun Carbon Nanotube Textiles Aligned by In Situ Radio-Frequency Fields

Removal of Hg(ii) in aqueous solutions through physical and chemical adsorption principles

Low voltage electric potential as a driving force to hinder biofouling in self-supporting carbon nanotube membranes

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