Preparation of high water flux and antifouling RO membranes using a novel diacyl chloride monomer with a phosphonate group

High water flux and salt selectivity have been the most demanding goals for osmosis-based membranes. Osmotic pressure differences across membranes are particularly important in emerging forward osmosis and pressure retarded...

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Single-File Water Flux Through Two-Dimensional Nanoporous Membranes

Nanoscale Research Letters ◽

10.1186/s11671-020-03436-4 ◽

2020 ◽

Vol 15 (1) ◽

Author(s):

Myung Eun Suk

Keyword(s):

Water Flux ◽

Interaction Strength ◽

High Water ◽

Potential Of Mean Force ◽

Proximal Region ◽

Dominant Factor ◽

Chemical Characteristics ◽

Nanoporous Membranes ◽

Two Dimensional ◽

Single File

Abstract Recent advances in the development of two-dimensional (2D) materials have facilitated a wide variety of surface chemical characteristics obtained by composing atomic species, pore functionalization, etc. The present study focused on how chemical characteristics such as hydrophilicity affects the water transport rate in hexagonal 2D membranes. The membrane–water interaction strength was tuned to change the hydrophilicity, and the sub-nanometer pore was used to investigate single-file flux, which is known to retain excellent salt rejection. Due to the dewetting behavior of the hydrophobic pore, the water flux was zero or nominal below the threshold interaction strength. Above the threshold interaction strength, water flux decreased with an increase in interaction strength. From the potential of mean force analysis and diffusion coefficient calculations, the proximal region of the pore entrance was found to be the dominant factor degrading water flux at the highly hydrophilic pore. Furthermore, the superiority of 2D membranes over 3D membranes appeared to depend on the interaction strength. The present findings will have implications in the design of 2D membranes to retain a high water filtration rate.

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Exploiting the Interplay between Liquid-Liquid Demixing and Crystallization of the PVDF Membrane for Membrane Distillation

International Journal of Polymer Science ◽

10.1155/2018/1525014 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10 ◽

Cited By ~ 5

Author(s):

N. I. M. Nawi ◽

M. R. Bilad ◽

N. A. H. M. Nordin ◽

M. O. Mavukkandy ◽

Z. A. Putra ◽

...

Keyword(s):

Polyvinylidene Fluoride ◽

Water Flux ◽

High Water ◽

Membrane Distillation ◽

Degree Of Crystallinity ◽

Solution Temperature ◽

Hydrophobic Membrane ◽

Sem Images ◽

Cold Temperatures ◽

Dope Solution

Membrane distillation (MD) purifies water by transporting its vapor through a hydrophobic membrane. An ideal MD membrane poses high water flux and high fouling, scaling, and wetting resistances. In this study, we develop polyvinylidene fluoride (PVDF) membranes for MD by focusing on reduction of PVDF degree of crystallinity. We explore the roles of dope solution temperature in dictating the phase separation mechanisms as well as the structure and the performance of semicrystalline PVDF membranes. DSC spectra show that higher dope solution temperature depresses crystallinity via formation of imperfect crystal. Such findings were also supported by FTIR and XRD results. The SEM images reveal formation of spherulite-like morphology in the membrane matrices for membranes prepared from high temperature dope solutions. A good balance between solid-liquid and liquid-liquid phase separations that offers low degree of crystallinity was found at a dope solution temperature of 60°C (PVDF-60), which showed the MD flux of 18 l/m2 h (vs. 6 l/m2 h for temperature of 25°C, as a benchmark) and nearly complete salt rejection when run at hot and cold temperatures of 65°C and 25°C, respectively. The PVDF-60 shows a high wetting resistance and stable MD flux of 10.5 l/m2 h over a 50 h test for treating brine solution as the feed (70 g NaCl/l).

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Slow hydrophobic hydration induced polymer ultrafiltration membranes with high water flux

Journal of Membrane Science ◽

10.1016/j.memsci.2014.07.073 ◽

2014 ◽

Vol 471 ◽

pp. 27-34 ◽

Cited By ~ 21

Author(s):

Kun Wang ◽

Xiaocheng Lin ◽

Gengping Jiang ◽

Jefferson Zhe Liu ◽

Lei Jiang ◽

...

Keyword(s):

Water Flux ◽

Hydrophobic Hydration ◽

High Water ◽

Ultrafiltration Membranes

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Cross-Linking With Diamine Monomers to Prepare Graphene Oxide Composite Membranes With Varying D-Spacing for Enhanced Desalination Properties

Frontiers in Chemistry ◽

10.3389/fchem.2021.779304 ◽

2021 ◽

Vol 9 ◽

Author(s):

Hong Ju ◽

Jinzhuo Duan ◽

Haitong Lu ◽

Weihui Xu

Keyword(s):

Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Water Flux ◽

Covalent Bond ◽

Composite Membranes ◽

Rejection Rate ◽

High Water ◽

Cross Linking ◽

Separation Performance ◽

X Ray

As a new type of membrane material, graphene oxide (GO) can easily form sub-nanometer interlayer channels, which can effectively screen salt ions. The composite membrane and structure with a high water flux and good ion rejection rate were compared by the cross-linking of GO with three different diamine monomers: ethylenediamine (EDA), urea (UR), and p-phenylenediamine (PPD). X-ray photoelectron spectroscopy (XPS) results showed that unmodified GO mainly comprises π-π interactions and hydrogen bonds, but after crosslinking with diamine, both GO and mixed cellulose (MCE) membranes are chemically bonded to the diamine. The GO-UR/MCE membrane achieved a water flux similar to the original GO membrane, while the water flux of GO-PPD/MCE and GO-EDA/MCE dropped. X-ray diffraction results demonstrated that the covalent bond between GO and diamine can effectively inhibit the extension of d-spacing during the transition between dry and wet states. The separation performance of the GO-UR/MCE membrane was the best. GO-PPD/MCE had the largest contact angle and the worst hydrophilicity, but its water flux was still greater than GO-EDA/MCE. This result indicated that the introduction of different functional groups during the diamine monomer cross-linking of GO caused some changes in the performance structure of the membrane.

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Water and solute permeability of rat lung caveolae: high permeabilities explained by acyl chain unsaturation

AJP Cell Physiology ◽

10.1152/ajpcell.00046.2005 ◽

2005 ◽

Vol 289 (1) ◽

pp. C33-C41 ◽

Cited By ~ 15

Author(s):

Warren G. Hill ◽

Eyad Almasri ◽

W. Giovanni Ruiz ◽

Gerard Apodaca ◽

Mark L. Zeidel

Keyword(s):

Water Permeability ◽

Acyl Chain ◽

Water Flux ◽

High Water ◽

Fatty Acyl ◽

Rat Lung ◽

Membrane Structures ◽

Solute Permeability ◽

Outer Leaflet ◽

Osmotic Water

Caveolae are invaginated membrane structures with high levels of cholesterol, sphingomyelin, and caveolin protein that are predicted to exist as liquid-ordered domains with low water permeability. We isolated a caveolae-enriched membrane fraction without detergents from rat lung and characterized its permeability properties to nonelectrolytes and protons. Membrane permeability to water was 2.85 ± 0.41 × 10−3 cm/s, a value 5–10 times higher than expected based on comparisons with other cholesterol and sphingolipid-enriched membranes. Permeabilities to urea, ammonia, and protons were measured and found to be moderately high for urea and ammonia at 8.85 ± 2.40 × 10−7and 6.84 ± 1.03 × 10−2 respectively and high for protons at 8.84 ± 3.06 × 10−2 cm/s. To examine whether caveolin or other integral membrane proteins were responsible for high permeabilities, liposomes designed to mimic the lipids of the inner and outer leaflets of the caveolar membrane were made. Osmotic water permeability to both liposome compositions were determined and a combined inner/outer leaflet water permeability was calculated and found to be close to that of native caveolae at 1.58 ± 1.1 × 10−3 cm/s. In caveolae, activation energy for water flux was high (19.4 kcal/mol) and water permeability was not inhibited by HgCl2; however, aquaporin 1 was detectable by immunoblotting. Immunostaining of rat lung with AQP1 and caveolin antisera revealed very low levels of colocalization. We conclude that aquaporin water channels do not contribute significantly to the observed water flux and that caveolae have relatively high water and solute permeabilities due to the high degree of unsaturation in their fatty acyl chains.

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Forward Osmosis: A Critical Review

Processes ◽

10.3390/pr8040404 ◽

2020 ◽

Vol 8 (4) ◽

pp. 404 ◽

Cited By ~ 7

Author(s):

Mehrdad Mohammadifakhr ◽

Joris de Grooth ◽

Hendrik D. W. Roesink ◽

Antoine J. B. Kemperman

Keyword(s):

Interfacial Polymerization ◽

Water Flux ◽

Forward Osmosis ◽

High Water ◽

Structural Parameter ◽

Selective Layer ◽

Internal Concentration ◽

Alternative Approaches ◽

Planar Geometries ◽

Dominant Influence

The use of forward osmosis (FO) for water purification purposes has gained extensive attention in recent years. In this review, we first discuss the advantages, challenges and various applications of FO, as well as the challenges in selecting the proper draw solution for FO, after which we focus on transport limitations in FO processes. Despite recent advances in membrane development for FO, there is still room for improvement of its selective layer and support. For many applications spiral wound membrane will not suffice. Furthermore, a defect-free selective layer is a prerequisite for FO membranes to ensure low solute passage, while a support with low internal concentration polarization is necessary for a high water flux. Due to challenges affiliated to interfacial polymerization (IP) on non-planar geometries, we discuss alternative approaches to IP to form the selective layer. We also explain that, when provided with a defect-free selective layer with good rejection, the membrane support has a dominant influence on the performance of an FO membrane, which can be estimated by the structural parameter (S). We emphasize the necessity of finding a new method to determine S, but also that predominantly the thickness of the support is the major parameter that needs to be optimized.

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Sol–gel preparation of PAA-g-PVDF/TiO2 nanocomposite hollow fiber membranes with extremely high water flux and improved antifouling property

Journal of Membrane Science ◽

10.1016/j.memsci.2012.12.041 ◽

2013 ◽

Vol 432 ◽

pp. 25-32 ◽

Cited By ~ 123

Author(s):

Feng Zhang ◽

Wenbin Zhang ◽

Yang Yu ◽

Bo Deng ◽

Jingye Li ◽

...

Keyword(s):

Hollow Fiber ◽

Sol Gel ◽

Water Flux ◽

High Water ◽

Hollow Fiber Membranes ◽

Antifouling Property ◽

Fiber Membranes ◽

Gel Preparation

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Ultrahigh-flux and fouling-resistant membranes based on layered silver/MXene (Ti3C2Tx) nanosheets

Journal of Materials Chemistry A ◽

10.1039/c7ta10888e ◽

2018 ◽

Vol 6 (8) ◽

pp. 3522-3533 ◽

Cited By ~ 104

Author(s):

Ravi P. Pandey ◽

Kashif Rasool ◽

Vinod E. Madhavan ◽

Brahim Aïssa ◽

Yury Gogotsi ◽

...

Keyword(s):

Composite Membrane ◽

Organic Molecules ◽

Water Flux ◽

High Water ◽

High Rejection

The 21% Ag@MXene composite membrane demonstrated an ultra-high water flux of 420 L m−2h−1bar−1and high rejection efficiency for organic molecules with excellent flux recovery.

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