scholarly journals Improved Hydrophilicity of Membrane by Ethylenediaminetetraacetic Acid Modification

2018 ◽  
Vol 23 (1) ◽  
Author(s):  
M. K. Chan ◽  
M. Letchumanan
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Water Flux ◽  
High Water ◽  
High Porosity ◽  
Acid Modification ◽  
Pore Former ◽  
Phase Inversion Technique ◽  
Blending Method ◽  
Wet Phase Inversion ◽  
Hydrophilic Membranes

Hydrophilic membranes exhibit good flux and low fouling tendency, which are the crucial criteria for a good membrane.  Attempts have been done by researchers over the past decades to enhance the hydrophilicity of membrane by using nanoparticles and grafting. However, these processes are tedious and costly. This study improves the hydrophilicity of cellulose acetate (CA) membranes by using ethylenediaminetetraacetic acid (EDTA) via simple blending method. Recent study showed that fouled membrane which was cleaned by EDTA exhibited high water flux performance. However, the use of EDTA in formulating a membrane has not been disclosed elsewhere. Thus, the objective of this study is to conduct a series of experiments to find out the role of EDTA in improving the hydrophilicity of CA membranes. Membranes with varying EDTA concentration were prepared via dry-wet phase inversion technique. Contact angle, porosity and water flux of the resultant membranes were determined. Additionally, the morphologies of the membranes were imaged using FESEM. Results showed that EDTA was a good pore former, which can be seen clearly from FESEM images. This explains for the high porosity properties in CA-EDTA membranes.  Membrane with 1 wt% of EDTA showed the highest water flux, which was ~15 L/(h.m2). Meanwhile, no water flux was observed after three hours when pure CA membrane was used in a dead-end filtration cell. In conclusion, EDTA is a promising additive in improving the hydrophilicity of membranes.

scholarly journals Understanding the morphology of MWCNT/PES mixed-matrix membranes using SANS: interpretation and rejection performance

2019 ◽  
Vol 9 (7) ◽  
Author(s):  
Km Nikita ◽  
P. Karkare ◽  
D. Ray ◽  
V. K. Aswal ◽  
Puyam S. Singh ◽  
...  
Keyword(s):  
Water Flux ◽  
High Water ◽  
Mixed Matrix Membranes ◽  
High Porosity ◽  
Mixed Matrix ◽  
Multiwalled Carbon ◽  
Working Pressure ◽  
Water Transportation ◽  
Phase Inversion Technique ◽  
Matrix Membranes

Abstract We describe the relationship between the morphology and rejection performance by the mixed-matrix membranes as a unique class of high water flux nanofiltration membranes comprising polyethersulfone/functionalized multiwalled carbon nanotubes (PES/f-MWCNTs). These membranes contain aligned MWCNTs uniformly distributed inside a PES matrix prepared using conventional phase-inversion technique. The small-angle neutron scattering analysis confirmed the high porosity and uniformity among of the pores of CNTs in the membranes. The frictionless water transport from vertically oriented f-MWCNTs were verified to facilitate remarkable enhancement in the water flux through the membranes. The water transportation speed, as well as rejection, of selected heavy metals increases nearly about 3 times and 2–3.5 times, respectively, than the pristine PES membrane, depending upon CNTs loading. Low working pressure and good retention properties make these membranes to be an ideal for the application of highly efficient filtration units.

scholarly journals High-performance cellulose acetate/polysulfone blend ultrafiltration membranes for removal of heavy metals from water

2017 ◽  
Vol 75 (10) ◽  
pp. 2422-2433 ◽  
Author(s):  
Pourya Moradihamedani ◽  
Abdul Halim Abdullah
Keyword(s):  
Heavy Metals ◽  
Cellulose Acetate ◽  
High Performance ◽  
Water Flux ◽  
Polymer Composition ◽  
Permeate Flux ◽  
Ultrafiltration Membranes ◽  
Pore Former ◽  
Phase Inversion Technique ◽  
The Impact

Neat cellulose acetate (CA) and CA/polysulfone (PSf) blend ultrafiltration membranes in the presence of polyvinylpyrrolidone as a pore former were prepared via a phase inversion technique. The prepared membranes were characterized by Fourier transform infrared, scanning electron microscopy, mechanical strength, water content, porosity, permeate flux and heavy metals (Pb2+, Cd2+, Zn2+ and Ni2+) rejection to comprehend the impact of polymer blend composition and additive on the properties of the modified membranes. The water flux expanded by increasing of PSf content in the polymer composition. CA/PSf (60/40) had the highest flux among prepared membranes. Prepared blend membranes were able to remove heavy metals from water in the following order: Pb2+ > Cd2+ > Zn2+ > Ni2+. The CA/PSf (80/20) blend membrane had great performance among prepared membranes due to the high heavy metals removal and permeate flux.

Enhancing Water Permeability with Super-hydrophilic Metal-Organic Frameworks and Hydrophobic Straight Pores

2021 ◽  
Author(s):  
Mehdi Habibollahzadeh ◽  
Juran Noh ◽  
Liang Feng ◽  
Hong-Cai Zhou ◽  
Ahmed Abdel-Wahab ◽  
...  
Keyword(s):  
Osmotic Pressure ◽  
Water Permeability ◽  
Metal Organic Frameworks ◽  
Water Flux ◽  
Forward Osmosis ◽  
High Water ◽  
Metal Organic

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...

scholarly journals Single-File Water Flux Through Two-Dimensional Nanoporous Membranes

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.

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

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
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).

Influence of Hydrophilic Polymer on Pure Water Permeation, Permeability Coefficient, and Porosity of Polysulfone Blend Membranes

2014 ◽  
Vol 931-932 ◽  
pp. 168-172 ◽  
Author(s):  
Asmadi Ali ◽  
Mohamad Awang ◽  
Ramli Mat ◽  
Anwar Johari ◽  
Mohd Johari Kamaruddin ◽  
...  
Keyword(s):  
Permeability Coefficient ◽  
Pure Water ◽  
Polymer Concentration ◽  
Water Flux ◽  
Hydrophilic Polymer ◽  
Hydrophobic Property ◽  
Water Permeation ◽  
Blend Membranes ◽  
Wet Phase Inversion ◽  
Pure Water Flux

It is well known that membrane with hydrophobic property is a fouling membrane. Polysulfone (PSf) membrane has hydrophobic characteristic was blended with a hydrophilic polymer, cellulose acetate phthalate (CAP) in order to increase hydrophilicity property of pure PSf membrane. In this study, membrane casting solutions containing 17 wt% of polymer was prepared via wet phase inversion process. The pure PSf membrane was coded as PC-0. PSf/CAP blend membranes with blend composition of 95/5, 90/10, 85/15 and 80/20 wt% of total polymer concentration in the membrane casting solutions were marked as PC-5, PC-10, PC-15 and PC-20 respectively. All of the membranes were characterized in terms of pure water flux and permeability coefficient in order to study their hydrophilicity properties. The investigated results shows that increased of CAP composition in PSf blend membranes has increased pure water flux, permeability coefficient and porosity of the blend membrane which in turn formed membrane with anti-fouling property.

Slow hydrophobic hydration induced polymer ultrafiltration membranes with high water flux

2014 ◽  
Vol 471 ◽  
pp. 27-34 ◽  
Author(s):  
Kun Wang ◽  
Xiaocheng Lin ◽  
Gengping Jiang ◽  
Jefferson Zhe Liu ◽  
Lei Jiang ◽  
...  
Keyword(s):  
Water Flux ◽  
Hydrophobic Hydration ◽  
High Water ◽  
Ultrafiltration Membranes

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

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.

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

2005 ◽  
Vol 289 (1) ◽  
pp. C33-C41 ◽  
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.

scholarly journals Mineralogical, Textural and Physical Characterisation to Determine Deterioration Susceptibility of Irulegi Castle Lime Mortars (Navarre, Spain)

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 584 ◽  
Author(s):  
Graciela Ponce-Antón ◽  
Anna Arizzi ◽  
Maria Zuluaga ◽  
Giuseppe Cultrone ◽  
Luis Ortega ◽  
...  
Keyword(s):  
Size Range ◽  
Local Environment ◽  
High Water ◽  
Absorption Capacity ◽  
Annual Rainfall ◽  
High Porosity ◽  
Repair Mortar ◽  
Lime Mortars ◽  
Historical Heritage ◽  
High Degree

Archaeological lime mortars from the Tower Keep and West perimeter wall of Irulegi Castle (Navarre, Spain) were analysed to determine susceptibility to deterioration. Chemical, mineralogical, textural and physical characterisation was performed by different tests and multianalysis techniques in order to determine the intrinsic features of the original historical mortars at the castle. Samples from the Tower Keep are more prone to deteriorate compared with the West perimeter wall due to high water absorption capacity and high porosity. A high degree of pore interconnection, high desorption index and the presence of high pore volume in the 0.01 to 1 µm size range affect the mortar durability since pores retain water longer inside the mortar. Local environment conditions with persistent annual rainfall, high humidity and temperature variations contribute to the decay process of the original mortar. Characterisation of historical mortars not only allows better understanding of susceptibility to deterioration but also helps the design of compatible and durable repair mortar for future interventions on historical heritage. Compatibility of new materials with the historical mortar will be ensured by studying mortar characteristics and properties.

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