scholarly journals Improving fouling resistance of seawater desalination membranes via surface modification

2013 ◽  
Vol 3 (3) ◽  
pp. 217-223
Author(s):  
Jong-Min Lee ◽  
Hyun-Woong Lee ◽  
Yeo-Jin Kim ◽  
Hyung-Gyu Park ◽  
Sung-Pyo Hong ◽  
...  
Keyword(s):  
Surface Modification ◽  
Surface Energy ◽  
Membrane Surface ◽  
Cross Flow ◽  
Lower Surface ◽  
Fouling Resistance ◽  
Surface Charges ◽  
Cross Flow Filtration ◽  
Modified Membrane ◽  
Surface Modified

A commercial polyamide seawater reverse osmosis membrane (Woongjin Chemical CSM) was surface-modified with fluoro-compounds. The effect of this surface modification on both water and NaCl permeability before and after organic fouling was investigated. The structural and electrical characteristics of the membrane surface were measured using atomic force microscopy and electrokinetic analysis respectively. When modified, the membrane surface showed only slight changes to the surface roughness and surface charges. The modified membrane also showed highly improved fouling resistance during cross-flow filtration of characteristic seawater organic foulants (humic acid and sodium alginate). Contact angle analysis using the Owens-Wendt theory was used to calculate the surface energy of the modified membrane. Lower surface energy of the modified membrane was identified as the key factor in the improved fouling resistance of the membranes.

scholarly journals Rapid Surface Modification of Ultrafiltration Membranes for Enhanced Antifouling Properties

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 401
Author(s):  
Noresah Said ◽  
Ying Siew Khoo ◽  
Woei Jye Lau ◽  
Mehmet Gürsoy ◽  
Mustafa Karaman ◽  
...  
Keyword(s):  
Surface Modification ◽  
Deposition Time ◽  
Plasma Deposition ◽  
Membrane Surface ◽  
Pure Water ◽  
Plasma Modification ◽  
Surface Hydrophilicity ◽  
Water Cleaning ◽  
Modification Method ◽  
Modified Membrane

In this work, several ultrafiltration (UF) membranes with enhanced antifouling properties were fabricated using a rapid and green surface modification method that was based on the plasma-enhanced chemical vapor deposition (PECVD). Two types of hydrophilic monomers—acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) were, respectively, deposited on the surface of a commercial UF membrane and the effects of plasma deposition time (i.e., 15 s, 30 s, 60 s, and 90 s) on the surface properties of the membrane were investigated. The modified membranes were then subjected to filtration using 2000 mg/L pepsin and bovine serum albumin (BSA) solutions as feed. Microscopic and spectroscopic analyses confirmed the successful deposition of AA and HEMA on the membrane surface and the decrease in water contact angle with increasing plasma deposition time strongly indicated the increase in surface hydrophilicity due to the considerable enrichment of the hydrophilic segment of AA and HEMA on the membrane surface. However, a prolonged plasma deposition time (>15 s) should be avoided as it led to the formation of a thicker coating layer that significantly reduced the membrane pure water flux with no significant change in the solute rejection rate. Upon 15-s plasma deposition, the AA-modified membrane recorded the pepsin and BSA rejections of 83.9% and 97.5%, respectively, while the HEMA-modified membrane rejected at least 98.5% for both pepsin and BSA. Compared to the control membrane, the AA-modified and HEMA-modified membranes also showed a lower degree of flux decline and better flux recovery rate (>90%), suggesting that the membrane antifouling properties were improved and most of the fouling was reversible and could be removed via simple water cleaning process. We demonstrated in this work that the PECVD technique is a promising surface modification method that could be employed to rapidly improve membrane surface hydrophilicity (15 s) for the enhanced protein purification process without using any organic solvent during the plasma modification process.

Surface modification of reverse osmosis membranes with zwitterionic polymer to reduce biofouling

2015 ◽  
Vol 15 (5) ◽  
pp. 999-1010 ◽  
Author(s):  
Ahmed E. Abdelhamid ◽  
Mahmoud M. Elawady ◽  
Mahmoud Ahmed Abd El-Ghaffar ◽  
Abdelgawad M. Rabie ◽  
Poul Larsen ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Tap Water ◽  
Membrane Surface ◽  
Salt Content ◽  
Cross Flow ◽  
Membrane Properties ◽  
Cleaning Efficiency ◽  
Bacteria Growth ◽  
Cross Flow Filtration

The zwitterionic homopolymer poly[2-(methacryloyloxy)ethyl-dimethyl-(3-sulfopropyl) ammonium hydroxide was coated onto the surface of commercial polyamide reverse osmosis (RO) membranes. Aqueous solutions of the polymer at different concentrations were applied to modify the polyamide membranes through an in situ surface coating procedure. After membrane modification, cross-flow filtration testing was used to test the antifouling potential of the modified membranes. The obtained data were compared with experimental data for unmodified membranes. Each test was done by cross-flow filtering tap water for 60 hours. Yeast extract was added as a nutrient source for the naturally occurring bacteria in tap water, to accelerate bacteria growth. Fourier transform infrared spectroscopy, contact angle, scanning electron microscopy, atomic force microscopy, and permeation tests were employed to characterize membrane properties. The results confirmed that modifying the membranes enhanced their antifouling properties and cleaning efficiency, the fouling resistance to bacteria improving due to the increased hydrophilicity of the membrane surface after coating. In addition, the water permeability and salt rejection improved. This in situ surface treatment approach for RO membranes could be very important for modifying membranes in their original module assemblies as it increases water production and reduces the salt content.

Facile fouling resistant surface modification of microfiltration cellulose acetate membranes by using amino acid l-DOPA

2013 ◽  
Vol 68 (4) ◽  
pp. 901-908 ◽  
Author(s):  
Sara Azari ◽  
Linda Zou ◽  
Emile Cornelissen ◽  
Yasushito Mukai
Keyword(s):  
Surface Modification ◽  
Amino Acid ◽  
Cellulose Acetate ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Fouling Resistance ◽  
Widespread Application ◽  
Potential Measurement ◽  
Cellulose Acetate Membranes ◽  
Microfiltration Membranes

A major obstacle in the widespread application of microfiltration membranes in the wet separation processes such as wastewater treatment is the decline of permeates flux as a result of fouling. This study reports on the surface modification of cellulose acetate (CA) microfiltration membrane with amino acid l-3,4-dihydroxy-phenylalanine (l-DOPA) to improve fouling resistance of the membrane. The membrane surface was characterised using Fourier transform infrared spectroscopy (FTIR), water contact angle and zeta potential measurement. Porosity measurement showed a slight decrease in membrane porosity due to coating. Static adsorption experiments revealed an improved resistance of the modified membranes towards the adhesion of bovine serum albumin (BSA) as the model foulant. Dead end membrane filtration tests exhibited that the fouling resistance of the modified membranes was improved. However, the effect of the modification depended on the foulant solution concentration. It is concluded that l-DOPA modification is a convenient and non-destructive approach to enable low-BSA adhesion surface modification of CA microfiltration membranes. Nevertheless, the extent of fouling resistance improvement depends on the foulant concentration.

Ultrafiltration of Aqueous Solutions of Food Dye in the Presence of Surfactants

2017 ◽  
Vol 68 (1) ◽  
pp. 6-10
Author(s):  
George Alexandru Popa ◽  
Daniela Florentina Popa (Enache) ◽  
Dumitra Daniela Slave (Clej) ◽  
Ion Din Spiridon ◽  
Cristina Monica Mirea ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Membrane Surface ◽  
Cross Flow ◽  
Sodium Octanoate ◽  
Food Dye ◽  
Cross Flow Filtration ◽  
Dead End ◽  
Food Dyes ◽  
Flow Filtration ◽  
Quinoline Yellow

The objective of the study is the low-pressure membrane process for treating aqueous solutions containing food dyes and surfactants. The influence of surfactants (SDS � sodium dedecil sulphate, SO � sodium octanoate) in the separation of synthetic food dyes (E104 � quinoline yellow) was analyzed. Polysulfone and polysulfone-polyaniline membranes were used. Dye and surfactant concentrations used were 10% (equivalent to 100g/m3). The pressures used in the ultrafiltration process were 0.1, 0.2 and 0.3 MPa. When dye containing solutions were passed through the membranes, an increase in their flux was observed. The presence of surfactants in the solutions lead to a decline in flux when pressures of 0.1 and 0.2 MPa were used, but an improvement could be seen as the pressure increased to 0.3 MPa, for both dead-end and cross-flow filtration. Using only dead-end alternative, higher fluxes were achieved for both membranes, but it decreases with time due to accumulation on the membrane surface. The use of cross-flow filtration did not allow accumulation on the membrane surface so that the flux was constant in time.The use of anionic surfactants improved the food dye retention. The interactions between membranes and surfactants can be an important factor supporting the efficiency of the ultrafiltration.

scholarly journals Understanding the Role of Pattern Geometry on Nanofiltration Threshold Flux

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 445
Author(s):  
Anna Malakian ◽  
Zuo Zhou ◽  
Lucas Messick ◽  
Tara N. Spitzer ◽  
David A. Ladner ◽  
...  
Keyword(s):  
Membrane Surface ◽  
Cross Flow ◽  
Cake Filtration ◽  
Cross Flow Filtration ◽  
Colloidal Fouling ◽  
Computational Fluid Dynamics Simulations ◽  
Flow Filtration ◽  
Dynamics Simulations ◽  
The Relationship

Colloidal fouling can be mitigated by membrane surface patterning. This contribution identifies the effect of different pattern geometries on fouling behavior. Nanoscale line-and-groove patterns with different feature sizes were applied by thermal embossing on commercial nanofiltration membranes. Threshold flux values of as-received, pressed, and patterned membranes were determined using constant flux, cross-flow filtration experiments. A previously derived combined intermediate pore blocking and cake filtration model was applied to the experimental data to determine threshold flux values. The threshold fluxes of all patterned membranes were higher than the as-received and pressed membranes. The pattern fraction ratio (PFR), defined as the quotient of line width and groove width, was used to analyze the relationship between threshold flux and pattern geometry quantitatively. Experimental work combined with computational fluid dynamics simulations showed that increasing the PFR leads to higher threshold flux. As the PFR increases, the percentage of vortex-forming area within the pattern grooves increases, and vortex-induced shielding increases. This study suggests that the PFR should be higher than 1 to produce patterned membranes with maximal threshold flux values. Knowledge generated in this study can be applied to other feature types to design patterned membranes for improved control over colloidal fouling.

Numerical Simulation of Filtration of Charged Oil Particles in Stationary and Rotating Tubular Membranes

2015 ◽  
Author(s):  
Sina Jahangiri Mamouri ◽  
Volodymyr V. Tarabara ◽  
André Bénard
Keyword(s):  
Flow Field ◽  
Electric Field ◽  
Electric Potential ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Cross Flow ◽  
Solid Cylinder ◽  
Permeate Flux ◽  
Cross Flow Filtration ◽  
Flow Filtration

Cross flow filtration (CFF) is a common membrane separation process with applications in food, biochemical and petroleum industries. In particular, membranes can be used for liquid-liquid separation processes such as needed in oil-water separation. A major challenge in cross flow filtration is membrane fouling. It can decrease significantly the permeate flux and a membrane’s efficiency. Membrane fouling can be mitigated by inducing shear on the membrane’s surface and this can be enhanced by inducing a swirl in the flow. In addition, a possible approach to improve membrane efficiency consists of repelling droplets/particles from the porous surface toward the centerline using a repulsive electric force. For this purpose, the surface of the membrane can be exposed to electric potential and droplets/particles are also induced to have the same electric charge. In this work, numerical simulations of charged non-deformable droplets moving within an axially rotating charged tubular membrane are performed. The results show that by increasing the electric potential on the membrane surface, the repelling force increases which obviously improves the grade efficiency of the membrane. However, the electric field gradients found in the flow field require large potentials on the membrane surface to observe a noticeable effect. Hence, a smaller solid cylinder is located in the centerline of the flow channel with zero potential. This solid cylinder enhances the electric field gradient in the domain which results in higher repelling forces and larger grade efficiency of the membrane at small potentials. The addition of a small cylinder in the flow field also improves the grade efficiency increases due to the higher shear stress near the membrane surface.

scholarly journals Improving Water Permeability of Hydrophilic PVDF Membrane Prepared via Blending with Organic and Inorganic Additives for Humic Acid Separation

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4099 ◽  
Author(s):  
Nasrul Arahman ◽  
Sri Mulyati ◽  
Afrillia Fahrina ◽  
Syawaliah Muchtar ◽  
Mukramah Yusuf ◽  
...  
Keyword(s):  
Humic Acid ◽  
Water Permeability ◽  
Polyvinylidene Fluoride ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Cross Flow ◽  
Chemical Compositions ◽  
Separation Performance ◽  
Pvdf Membrane ◽  
Cross Flow Filtration

The removal of impurities from water or wastewater by the membrane filtration process has become more reliable due to good hydraulic performance and high permeate quality. The filterability of the membrane can be improved by having a material with a specific pore structure and good hydrophilic properties. This work aims at preparing a polyvinylidene fluoride (PVDF) membrane incorporated with phospholipid in the form of a 2-methacryloyloxyethyl phosphorylcholine, polymeric additive in the form of polyvinylpyrrolidone, and its combination with inorganic nanosilica from a renewable source derived from bagasse. The resulting membrane morphologies were analyzed by using scanning electron microscopy. Furthermore, atomic force microscopy was performed to analyze the membrane surface roughness. The chemical compositions of the resulting membranes were identified using Fourier transform infrared. A lab-scale cross-flow filtration system module was used to evaluate the membrane’s hydraulic and separation performance by the filtration of humic acid (HA) solution as the model contaminant. Results showed that the additives improved the membrane surface hydrophilicity. All modified membranes also showed up to five times higher water permeability than the pristine PVDF, thanks to the improved structure. Additionally, all membrane samples showed HA rejections of 75–90%.

scholarly journals Surface Modification of Polyamide Ultrafiltration Membrane by Plasma Polymerisation of Acrylic Acid

2020 ◽  
Vol 49 (12) ◽  
pp. 3043-3050
Author(s):  
A. Suhaimi ◽  
E. Mahmoudi ◽  
K.S. Siow ◽  
M.F. Mohd Razip Wee
Keyword(s):  
Surface Modification ◽  
Acrylic Acid ◽  
Deposition Time ◽  
Cross Flow ◽  
Permeate Flux ◽  
Filtration Membrane ◽  
Cross Flow Filtration ◽  
Membrane Fabrication ◽  
Flow Filtration ◽  
Fouling Reduction

Increase in hydrophilicity of the filtration membrane could attribute to the fouling reduction and overall filtration performance. In this study, we employ a surface modification on polyamide (PA) membrane by using plasma polymerization with acrylic acid as the precursor by varying the deposition time from 1 to 10 min to induce hydrophilic surface of the membrane without changing the bulk properties of PA membrane. Cross-flow filtration of humic acid using the modified PA membrane was conducted to measure permeates flux and rejection. We calculate the fouling tendencies of each membrane and the result indicates the best performance from sample with 7 min deposition time in terms of permeate flux, rejection and the lowest fouling tendencies. Therefore, this proposed technique could be useful to further improve the commercial filtration membrane; without changing the membrane fabrication process.

Evaluation of Virus Removal in Membrane Separation Processes Using Coliphage Qβ

1993 ◽  
Vol 28 (7) ◽  
pp. 9-15 ◽  
Author(s):  
Taro Urase ◽  
Kazuo Yamamoto ◽  
Shinichiro Ohgaki
Keyword(s):  
Membrane Separation ◽  
Membrane Surface ◽  
Cross Flow ◽  
Pond Water ◽  
High Concentration ◽  
Separation Processes ◽  
Surface Deposit ◽  
Virus Removal ◽  
Cross Flow Filtration ◽  
Flow Filtration

Virus removal in membrane separation processes was investigated by employing coliphage Qβ as a tracer. Several types of microfiltration membrane and ultrafiltration membrane were tested. Two types of filtration experiments were carried out; dead-end filtration and cross-flow filtration. The membrane surface deposits played an important role in the rejection of viruses in the filtration of activated sludge and pond-water, whereas acrylate polymer cake did not affect the rejection of Qβ. The leakage of ultrafiltration membranes was well examined by the high concentration of Qβ applied. The major part of the rejected coliphages were adsorbed onto the membrane and in its surface deposit.

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