Formation of electrically conductive hollow fiber membranes via crossflow deposition of carbon nanotubes – Addressing the conductivity/permeability trade-off

Larocque, Melissa; Latulippe, David R.; Lannoy, Charles‐François de

doi:10.1016/j.memsci.2020.118859

Cited by 14 publications

(7 citation statements)

References 56 publications

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“…Our cost analysis based on the CNT-ECMs used in this study indicates that coating a porous UF polymeric support (PES) with functionalized multi-walled CNTs to a surface coating thickness of 1 μm would cost $2.88/m 2 , equal to 0.4% in total material cost. Manufacturing methods are currently only appropriate for lab-scale development, although recent hollow fiber coating techniques by our lab 81 and others 82 indicate some promise for scalable techniques. Module designs have been proposed but are still lacking.…”

Section: E Colimentioning

confidence: 99%

Quantifying the Impact of Electrically Conductive Membrane-Generated Hydrogen Peroxide and Extreme pH on the Viability of Escherichia coli Biofilms

Halali

Lannoy

2021

Ind. Eng. Chem. Res.

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Electrically conductive membranes (ECMs) self-induce antifouling mechanisms at their surface under certain applied electrical currents. Quantifying these mechanisms is critical to enhancing ECMs' self-cleaning performance. Local pH change and H 2 O 2 production are among the most important self-cleaning mechanisms previously hypothesized for ECMs. However, the impacts of these mechanisms have not previously been isolated and comprehensively studied. In this study, we quantified the individual impact of electrochemically induced acidic conditions, alkaline conditions, and H 2 O 2 concentration on model bacteria, Escherichia coli. To this end, we first quantified the electrochemical potential of carbon nanotube-based ECMs to generate stressors, such as protons, hydroxyl ions, and H 2 O 2 , under a range of applied electrical currents (±0−150 mA, 0−2.7 V). Next, these chemical stressors with similar magnitude to that generated at the ECM surfaces were imposed on E. coli cells and biofilms. In the flow-through ECM systems, biofilm viability using LIVE/DEAD staining indicated biofilm viabilities of 39 ± 9.9%, 38 ± 4.7%, 45 ± 5.0%, 34 ± 3.1%, and 75 ± 4.9% after separate exposure to pH 3.5, anodic potential (2 V), pH 11, cathodic potential (2 V), and H 2 O 2 concentration (188 μM). Electrical current-induced pH change at the membrane surface was shown to be more effective in reducing bacterial viability than H 2 O 2 generation and more efficient than bulk pH changes. This study identified antibiofouling mechanisms of ECMs and provides guidance for determining the current patterns that maximize their antifouling effects.

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Section: E Colimentioning

confidence: 99%

Quantifying the Impact of Electrically Conductive Membrane-Generated Hydrogen Peroxide and Extreme pH on the Viability of Escherichia coli Biofilms

Halali

Lannoy

2021

Ind. Eng. Chem. Res.

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“…The following procedure is the self-assembly of CNTs, which forms a macrostructure composed of randomly entangled CNTs. This process is typically achieved by evaporation, filtration or crossflow deposition 73 of the CNT dispersion. The resultant CNT membranes typically have a nanometer-thin structure and can also be thick enough to act as a free-standing structure.…”

Section: Cnt-based Membranesmentioning

confidence: 99%

Carbon nanomaterial-based membranes for water and wastewater treatment under electrochemical assistance

Fan

Wei

Quan

2023

Environ. Sci.: Nano

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“…14 While some of these methods were successful with some polymeric membranes such as poly(ether sulfone) (PES), 15,16 cellulose nitrate, 7 and poly(ethylene terephthalate), 14 no methods have yet been developed to create stable ECMs on chemically inert poly(vinylidene fluoride) (PVDF) membranes. 14,17 Furthermore, some additives and cross-linkers, such as PVA, have been demonstrated to leach from the membrane under concentration polarization, leading to unstable CNT cross-linking and variable surface conductivities. 10 PVDF is one of the most prevalent polymers used to make MF and UF membranes, yet no stable ECMs have been made using PVDF; its thermal stability and chemical inertness limit its surface modification.…”

Section: Introductionmentioning

confidence: 99%

“…10 PVDF is one of the most prevalent polymers used to make MF and UF membranes, yet no stable ECMs have been made using PVDF; its thermal stability and chemical inertness limit its surface modification. 15,18 There is thus a need to develop effective binding methods to attach conductive materials such as CNTs to polymer supports in general and especially for PVDF-based ECMs. In addition, any developed ECM chemistry must be optimized to maximize its surface conductivity, minimize the permeability loss associated with the coating, and demonstrate physical and chemical stability.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Poly(vinylidene fluoride) (PVDF) Membranes Using Polyethylenimine Cross-Linked Polydopamine-Bound Carbon Nanotubes

Awad,

de Lannoy

2024

ACS Appl. Polym. Mater.

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Electrochemical membranes (ECMs) are an emerging multifunctional separation technology that enables simultaneous contaminant filtration and reaction due to their electrically conductive porous surface coatings. Physical coating stability remains a technical challenge for ECMs, which are largely based on carbonaceous nanomaterials or metallic thin films. In this research, binding chemistry based on polydopamine (PDA) and polyethylenimine (PEI) was developed to prepare physically stable ECMs. Poly(vinylidene fluoride) (PVDF) ultrafiltration membranes were coated with PEI cross-linked PDA followed by the deposition of carboxylfunctionalized single/double-walled carbon nanotubes (SW/DWCNTs-COOH). Fabricated membranes were characterized for their structural, physicochemical, electrochemical, and separation properties. In a batch electrochemical system, the membranes achieved >99.2% electrochemical reduction of methyl orange (MO) in 120 min. Results revealed that the PDA/PEI intermediate layer can significantly enhance the adhesion between the SW/DWCNTs and the underlying polymer membrane without a substantial reduction (<10%) in water permeability. Response surface methodology (RSM) was employed to optimize the permeability and surface electrical conductivity of ECMs by studying the influence of PDA concentration, PEI concentration, and the branched-amine content of PEI in the coating solution. RSM analysis demonstrated two factorial interactions between PDA and PEI concentrations, as well as PEI concentration and PEI branch molecular weight. Our optimization study revealed that the use of a 1:1 ratio of PDA/PEI at low concentrations (∼2 mg/mL) and high PEI branch M w (∼1200) was the ideal preparation condition within the tested design space to maximize both the water permeability (∼895 L/m 2 /h/bar) and electrical conductivity (∼29,761 S/m). This optimized cross-linking chemistry demonstrates the ability to make practical and physically stable ECMs on chemically inert PVDF membranes, expanding the range of membranes that can be used to create electrochemical membranes.

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Formation of electrically conductive hollow fiber membranes via crossflow deposition of carbon nanotubes – Addressing the conductivity/permeability trade-off

Cited by 14 publications

References 56 publications

Quantifying the Impact of Electrically Conductive Membrane-Generated Hydrogen Peroxide and Extreme pH on the Viability of Escherichia coli Biofilms

Quantifying the Impact of Electrically Conductive Membrane-Generated Hydrogen Peroxide and Extreme pH on the Viability of Escherichia coli Biofilms

Carbon nanomaterial-based membranes for water and wastewater treatment under electrochemical assistance

Electrochemical Poly(vinylidene fluoride) (PVDF) Membranes Using Polyethylenimine Cross-Linked Polydopamine-Bound Carbon Nanotubes

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