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.

scholarly journals Elution Is a Critical Step for Recovering Human Adenovirus 40 from Tap Water and Surface Water by Cross-Flow Ultrafiltration

2016 ◽  
Vol 82 (16) ◽  
pp. 4982-4993 ◽  
Author(s):  
Hang Shi ◽  
Irene Xagoraraki ◽  
Kristin N. Parent ◽  
Merlin L. Bruening ◽  
Volodymyr V. Tarabara
Keyword(s):  
Surface Water ◽  
Hydrophobic Interactions ◽  
Tap Water ◽  
Calf Serum ◽  
Cross Flow ◽  
Human Adenovirus ◽  
Deionized Water ◽  
Feed Water ◽  
Eluent Composition ◽  
Cross Flow Filtration

ABSTRACTThis paper examines the recovery of the enteric adenovirus human adenovirus 40 (HAdV 40) by cross-flow ultrafiltration and interprets recovery values in terms of physicochemical interactions of virions during sample concentration. Prior to ultrafiltration, membranes were either blocked by exposure to calf serum (CS) or coated with a polyelectrolyte multilayer (PEM). HAdV 40 is a hydrophobic virus with a point of zero charge between pH 4.0 and pH 4.3. In accordance with predictions from the extended Derjaguin-Landau-Verwey-Overbeek theory, the preelution recovery of HAdV (rpre) from deionized water was higher with PEM-coated membranes (rprePEM= 74.8% ± 9.7%) than with CS-blocked membranes (rpreCS= 54.1% ± 6.2%). With either membrane type, the total virion recovery after elution (rpost) was high for both deionized water (rpostPEM= 99.5% ± 6.6% andrpostCS= 98.8% ± 7.7%) and tap water (rpostPEM= 89% ± 15% andrpostCS= 93.7% ± 6.9%). The nearly 100% recoveries suggest that the polyanion (sodium polyphosphate) and surfactant (Tween 80) in the eluent disrupt electrostatic and hydrophobic interactions between the virion and the membrane. Addition of EDTA to the eluent greatly improved the elution efficacy (rpostCS= 88.6% ± 4.3% andrpostPEM= 87.0% ± 6.9%) with surface water, even when the organic carbon concentration in the water was high (9.4 ± 0.1 mg/liter). EDTA likely disrupts cation bridging between virions and particles in the feed water matrix or the fouling layer on the membrane surface. For complex water matrices, the eluent composition is the most important factor for achieving high virion recovery.IMPORTANCEHerein we present the results of a comprehensive physicochemical characterization of HAdV 40, an important human pathogen. The data on HAdV 40 surface properties enabled rigorous modeling to gain an understanding of the energetics of virion-virion and virion-filter interactions. Cross-flow filtration for concentration and recovery of HAdV 40 was evaluated, with postelution recoveries from ultrapure water (99%), tap water (∼91%), and high-carbon-content surface water (∼84%) being demonstrated. These results are significant because of the very low adenovirus recoveries that have been reported, to date, for other methods. The recovery data were interpreted in terms of specific interactions, and the eluent composition was designed accordingly to maximize HAdV 40 recovery.

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 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.

Rapid novel test for the determination of biofouling potential on reverse osmosis membranes

2016 ◽  
Vol 73 (12) ◽  
pp. 2978-2985 ◽  
Author(s):  
Cervinia V. Manalo ◽  
Masaki Ohno ◽  
Tetsuji Okuda ◽  
Satoshi Nakai ◽  
Wataru Nishijima
Keyword(s):  
Reverse Osmosis ◽  
Fluorescence Intensity ◽  
Biofilm Formation ◽  
Membrane Surface ◽  
Cross Flow ◽  
Direct Analysis ◽  
Novel Method ◽  
Ro Membrane ◽  
Flow Experiments

Abstract A novel method was proposed to determine biofouling potential by direct analysis of a reverse osmosis (RO) membrane through fluorescence intensity analysis of biofilm formed on the membrane surface, thereby incorporating fouling tendencies of both feedwater and membrane. Evaluation of the biofouling potential on the RO membrane was done by accelerated biofilm formation through soaking of membranes in high biofouling potential waters obtained by adding microorganisms and glucose in test waters. The biofilm formed on the soaked membrane was quantified by fluorescence intensity microplate analysis. The soaking method's capability in detecting biofilm formation was confirmed when percentage coverage obtained through fluorescence microscopy and intensity values exhibited a linear correlation (R2 = 0.96). Continuous cross-flow experiments confirmed the ability and reliability of the soaking method in giving biofouling potential on RO membranes when a good correlation (R2 = 0.87) between intensity values of biofilms formed on the membrane during soaking and filtration conditions was obtained. Applicability of the test developed was shown when three commercially available polyamide (PA) RO membranes were assessed for biofouling potential. This new method can also be applied for the determination of biofouling potential in water with more than 3.6 mg L−1 easily degradable organic carbon.

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 Important Approaches to Enhance Reverse Osmosis (RO) Thin Film Composite (TFC) Membranes Performance

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 68 ◽  
Author(s):  
Ahmed Al Mayyahi
Keyword(s):  
Thin Film ◽  
Reverse Osmosis ◽  
Membrane Surface ◽  
Membrane Properties ◽  
Major Type ◽  
Future Research ◽  
Human Consumption ◽  
Film Composite ◽  
Thin Film Composite ◽  
Tfc Membrane

Thin film composite (TFC) membrane, which consists of polyamide (PA) active film rests on porous support layer, has been the major type of reverse osmosis (RO) membrane since its development by Cadotte in the 1970s, and has been remarkably used to produce clean water for human consumption and domestic utilization. In the past 30 years, different approaches have been exploited to produce the TFC membrane with high water flux, excellent salt rejection, and better chlorine/fouling resistance. In this brief review, we classify the techniques that have been utilized to improve the RO-TFC membrane properties into four categories: (1) Using alternative monomers to prepare the active layer; (2) modification of membrane surface; (3) optimization of polymerization reactions; and (4) incorporation of nanoparticles (NPs) into the membrane PA layer. This review can provide insights to guide future research and further propel the RO TFN membrane.

Sign in / Sign up

Export Citation Format

Share Document