Regulating the integrity of diverse composite nanofiber membranes using an organoclay

Jang, Wongi; Park, Yeji; Park, Chanju; Seo, Younggee; Kim, Jun‐Hyun; Jian, Hou; Byun, Hongsik

doi:10.1016/j.memsci.2019.117670

Cited by 14 publications

(12 citation statements)

References 56 publications

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“…The presence of CNF in the calcium alginate membrane noticeably increased the water flux at the same pressure. This is a commonly observed result in the performance of CNF [26,27] and is in accordance with Hagen -Poiseuille flow. It can be expressed via non-equilibrium thermodynamic theory using Eq.…”

Section: Mechanical Strengthsupporting

confidence: 86%

Multiphase calcium alginate membrane composited with cellulose nanofibers for selective mass transfer

2020

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A multiphase calcium alginate membrane composited with cellulose nanofibers (CNF) was successfully prepared by using the method. The maximum stress and strain, water content, water permeability, and mass transfer characteristics were examined according to the addition ratio of CNF. Increasing of the amount of CNF enhanced the maximum stress and reduced the maximum strain, thereby suggesting that CNF impart flexibility and stiffness to the composite membrane. The CNF in the calcium alginate noticeably increased the water flux at the same pressure. The permeability of the composite of the CNF membrane was higher. The effective diffusion coefficient dramatically decreased 2.5 × 10 3 times when the molecular weight increased tenfold (from 60 to 604 Da). Moreover, stronger dependency was observed in the CNF composite membrane. The morphology of the cross-section of the membrane was observed using scanning electron microscopy. The appearance of the CNF composite membrane became rougher when the amount of CNF increased. Keywords Cellulose nanofiber • Membrane • Mechanical strength • Effective diffusion coefficient • Water permeability List of symbols A c Initial membrane cross-sectional area (m 2) A m Effective area of the membrane (m 2) B max Maximum breaking load (N) C fi Initial concentration in the feed solution (mol/L) C s Concentration in the stripping solution (mol/L) D Diffusion coefficient estimated from an empirical equation in the bulk aqueous phase (m 2 s −1) D eff Effective diffusion coefficient (m 2 s −1) d Diameter of glass petri dish (m) H V Volumetric water content of membrane, defined by Eq. (4) (-) J V Volumetric water flux (m 3 water m −2 area s −1) K OL Overall mass transfer coefficient (m s −1) k m Membrane mass transfer coefficient (m s −1) L Length of membrane at break (m) L i Initial length of membrane (m) L p Water permeability coefficient (m 3 water m −2 area m −1 thickness Pa −1 s −1) l m Membrane thickness (m) * Ryo-ichi Nakayama,

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Section: Mechanical Strengthsupporting

confidence: 86%

Multiphase calcium alginate membrane composited with cellulose nanofibers for selective mass transfer

2020

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“…As shown in Figure 5 a, the bare-PAN membrane exhibited the lowest water permeability (~300 LMH), while the GO-PAN membrane showed over two times higher values (~650 LMH), possibly due to its improved hydrophilicity and bigger pore size. Despite its small pore size, Ag/GO-PAN showed slightly increased water permeability (~390 LMH) compared to that of bare-PAN which possibly due to its pore distribution and shape associated with the tortuosity of cross-section [ 15 , 39 ]. Therefore, the interconnected status of nanofillers into polymer matrix can highly influence the mass transport of water through pore channels by varying pore size, pore uniformity, and tortuosity of the cross-section.…”

Section: Resultsmentioning

confidence: 99%

“…The bare PAN, PAN/GO, and Ag/GO-PAN nanofiber membrane were prepared by our developed approach [ 29 , 30 , 39 ]. Initially, the synthesized GO (0.02 g) and Ag/GO nanosheets (0.02 g) were completely dispersed in a DMF solvent (10 mL) by sonicating for 2 h at rt.…”

Section: Methodsmentioning

confidence: 99%

Polyacrylonitrile Nanofiber Membrane Modified with Ag/GO Composite for Water Purification System

et al. 2020

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Silver nanoparticle-modified graphene oxide (Ag/GO) was reliably prepared by using sodium borohydride (NaBH4) in the presence of citric acid capping agent via a simple wet chemistry method. This rapidly formed Ag/GO composite exhibited good dispersity in a solution containing hydrophilic polyacrylonitrile (PAN). Subsequent electrospinning of this precursor solution resulted in the successful formation of nanofibers without any notable defects. The Ag/GO-incorporated PAN nanofibers showed thinner fiber strands (544 ± 82 nm) compared to those of GO-PAN (688 ± 177 nm) and bare-PAN (656 ± 59 nm). Subsequent thermal treatment of nanofibers resulted in the preparation of thin membranes to possess the desired pore property and outstanding wettability. The Ag/GO-PAN nanofiber membrane also showed 30% higher water flux value (390 LMH) than that of bare-PAN (300 LMH) for possible microfiltration (MF) application. In addition, the resulting Ag/GO-PAN nanofiber membrane exhibited antibacterial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). Furthermore, this composite membrane exhibited outstanding anti-fouling property compared to the GO-PAN nanofiber membrane in the wastewater treatment. Therefore, the simple modification strategy allows for the effective formation of Ag/GO composite as a filler that can be reliably incorporated into polymer nanofiber membranes to possess improved overall properties for wastewater treatment applications.

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“…However, the use of fillers also requires the extensive optimization of the electrospinning conditions via trial and error to avoid the destruction of their original structures due to their immiscibility [ 1 , 2 ]. Among many filler materials [ 8 , 15 , 16 , 17 , 18 , 19 , 20 ], graphene oxide (GO) is of particular interest because it is inexpensive and possesses various physical properties, as well as easy surface functionalization. The integration of GO into polymeric materials has several potential advantages, including promoting an increase in the mechanical strength, permeability, selectivity, and antifouling properties [ 10 , 21 , 22 , 23 , 24 , 25 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

Mixed Dye Removal Efficiency of Electrospun Polyacrylonitrile–Graphene Oxide Composite Membranes

et al. 2020

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Exfoliated graphene oxide (GO) was reliably modified with a cetyltrimethylammonium chloride (CTAC) surfactant to greatly improve the dispersity of the GO in a polyacrylonitrile (PAN) polymer precursor solution. Subsequent electrospinning of the mixture readily resulted in the formation of GO–PAN composite nanofibers containing up to 30 wt % of GO as a filler without notable defects. The absence of common electrospinning problems associated with clogging and phase separation indicated the systematic and uniform integration of the GO within the PAN nanofibers beyond the typical limits. After thoroughly examining the formation and maximum loading efficiency of the modified GO in the PAN nanofibers, the resulting composite nanofibers were thermally treated to form membrane-type sheets. The wettability and pore properties of the composite membranes were notably improved with respect to the pristine PAN nanofiber membrane, possibly due to the reinforcing filler effect. In addition, the more GO loaded into the PAN nanofiber membranes, the higher the removal ability of the methylene blue (MB) and methyl red (MR) dyes in the aqueous system. The adsorption kinetics of a mixed dye solution were also monitored to understand how these MB and MR dyes interact differently with the composite nanofiber membranes. The simple surface modification of the fillers greatly facilitated the integration efficiency and improved the ability to control the overall physical properties of the nanofiber-based membranes, which highly impacted the removal performance of various dyes from water.

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Regulating the integrity of diverse composite nanofiber membranes using an organoclay

Cited by 14 publications

References 56 publications

Multiphase calcium alginate membrane composited with cellulose nanofibers for selective mass transfer

Multiphase calcium alginate membrane composited with cellulose nanofibers for selective mass transfer

Polyacrylonitrile Nanofiber Membrane Modified with Ag/GO Composite for Water Purification System

Mixed Dye Removal Efficiency of Electrospun Polyacrylonitrile–Graphene Oxide Composite Membranes

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