scholarly journals Modification of a polyamide reverse osmosis membrane by heat treatment for enhanced fouling resistance

2013 ◽  
Vol 13 (6) ◽  
pp. 1553-1559 ◽  
Author(s):  
Takahiro Fujioka ◽  
Long D. Nghiem
Keyword(s):  
Heat Treatment ◽  
Reverse Osmosis ◽  
Membrane Surface ◽  
Pure Water ◽  
Surface Characteristics ◽  
Skin Layer ◽  
Secondary Effluent ◽  
Fouling Resistance ◽  
Flux Decline ◽  
Ro Membrane

The use of heat treatment to improve solute rejection and fouling resistance of a polyamide reverse osmosis (RO) membrane was investigated in this study. Heat treatment was carried out by immersing the membrane samples in Milli-Q water at 70 °C for a specific duration. Heat treatment (24 h) reduced the pure water permeability from 4.1 to 2.8 L/m2hbar but improved conductivity rejection from 95.5 to 97.0%. As a result, a correlation was observed between changes in the two parameters. Marginal changes in the membrane surface characteristics (i.e. zeta potential, hydrophobicity, chemistry and roughness) were observed as a result of heat treatment. Heat treatment significantly improved the fouling resistance property of the RO membrane. When the secondary effluent was filtrated at an elevated permeated flux, the virgin RO membrane exhibited 30% flux decline while the heat-treated membrane showed only 12% flux decline. This is possibly because heat treatment resulted in a denser cross-linked active skin layer, thus reducing the blockage caused by small organic foulants.

scholarly journals Fouling behaviour of a reverse osmosis membrane by three types of surfactants

2012 ◽  
Vol 2 (1) ◽  
pp. 40-46 ◽  
Author(s):  
Naoyuki Kishimoto ◽  
Honami Kimura
Keyword(s):  
Surface Charge ◽  
Reverse Osmosis ◽  
Anionic Surfactant ◽  
Membrane Fouling ◽  
Surfactant Concentration ◽  
Membrane Surface ◽  
Pure Water ◽  
Ionic Surfactants ◽  
Lauryl Sulfate ◽  
Ro Membrane

The fouling behaviour of a reverse osmosis (RO) membrane by three types of surfactants and a countermeasure to the fouling were studied. The filtration experiments showed that the permeability during filtration depended on the surfactant concentration and the charge of surfactant. Higher surfactant concentration deteriorated the permeability due to the concentration polarization. A negatively charged anionic surfactant, sodium lauryl sulfate (SLS), had less influence on the permeability than cationic and non-ionic surfactants. As the RO membrane used in this research had a hydrophilic and negatively charged membrane surface, adsorption of the anionic surfactant was prevented by the electrostatic force between the membrane surface and the hydrophilic group of the surfactant. To control the fouling by the cationic and non-ionic surfactants, addition of SLS to the surfactant solution was tested. Consequently, the addition of excess SLS changed the surface charge of aggregates into more negative value and the permeability during filtration was successfully improved. Furthermore, the drop in pure water permeability after filtration was not observed by the addition of excess SLS. Thus, the modification of charge of solutes to the same sign of the membrane surface charge was thought to be useful to control a membrane fouling by surfactants.

scholarly journals Effect of heat treatment on fouling resistance and the rejection of small and neutral solutes by reverse osmosis membranes

2014 ◽  
Vol 15 (3) ◽  
pp. 510-516 ◽  
Author(s):  
Takahiro Fujioka ◽  
Nagayasu Oshima ◽  
Ryoichi Suzuki ◽  
Michael Higgins ◽  
William E. Price ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Reverse Osmosis ◽  
Free Volume ◽  
Membrane Fouling ◽  
Volume Fraction ◽  
Membrane Surface ◽  
Feed Solution ◽  
Membrane Properties ◽  
Permeate Flux ◽  
Fouling Resistance

The effects of heat treatment on membrane fouling resistance and the rejection of small and neutral solutes by reverse osmosis (RO) membranes were elucidated. RO membrane modification by heat treatment reduced fouling and improved boron rejection. However, heat treatment also caused a decrease in the water permeability of RO membranes. Significant improvement on fouling resistance by heat treatment was observed when RO concentrate was used to simulate a feed solution with high fouling propensity. The improved fouling resistance is likely to be due to changes in the hydrophobic interaction between the membrane surface and foulants. Boron rejection by the ESPA2 membrane was enhanced by heat treatment from 26 to 68% (when evaluated at the permeate flux of 20 L/m2 h). Positron annihilation lifetime spectroscopy revealed that heat treatment did not significantly influence the free-volume hole-radius of the membrane active skin layer. The results reported in this study suggested that changes in the other membrane properties such as free-volume fraction and thickness may be the main cause improving boron rejection.

scholarly journals Influence of bulk concentration on the organisation of molecules at a membrane surface and flux decline during reverse osmosis of an anionic surfactant

2016 ◽  
Vol 499 ◽  
pp. 257-268 ◽  
Author(s):  
Zhaohuan Mai ◽  
Vincent Butin ◽  
Mohammed Rakib ◽  
Haochen Zhu ◽  
Murielle Rabiller-Baudry ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Anionic Surfactant ◽  
Membrane Surface ◽  
Bulk Concentration ◽  
Flux Decline

Topology Optimization of Spacers for Maximizing Permeate Flux on Membrane Surface in Reverse Osmosis Channel

2011 ◽  
Author(s):  
Seungjae Oh ◽  
Semyung Wang ◽  
Minkyu Park ◽  
Joonha Kim
Keyword(s):  
Topology Optimization ◽  
Pressure Drop ◽  
Reverse Osmosis ◽  
Membrane Surface ◽  
Design Development ◽  
Permeate Flux ◽  
Membrane Channel ◽  
Initial Attempt ◽  
Membrane Surfaces ◽  
Ro Membrane

The objective of this study is to design spacers using fluid topology optimization in 2D crossflow Reverse Osmosis (RO) membrane channel to improve the performance of RO processes. This study is an initial attempt to apply topology optimization to designing spacers in RO membrane channel. The performance was evaluated by the quantity of permeate flux penetrating both upper and lower membrane surfaces. A coupled Navier-Stokes and Convection-Diffusion model was employed to calculate the permeate flux. To get reliable solutions, stabilization methods were employed with standard finite element method. The nine reference models which consist of the combination of circle, rectangular, triangle shape and zigzag, cavity, submerge configuration of spacers were simulated. Such models were compared with new model designed by topology optimization. The permeate flux at both membrane surfaces was determined as an objective function. In addition, permissible pressure drop along the channel and spacer volume were used as constraints. As a result of topology optimization as the permissible pressure drop changes in channel, characteristics of spacer design development was founded. Spacer design based on topology optimization was reconstructed to a simple one considering manufactuability and characteristics of development spacer design. When a simplified design was compared with previous 9 models, new design has a better performance in terms of permeate flux and wall concentration at membrane surface.

scholarly journals Silica scale formation and effect of sodium and aluminium ions -29Si NMR study

2016 ◽  
Vol 2 (1) ◽  
pp. 174-185 ◽  
Author(s):  
L. Lunevich ◽  
P. Sanciolo ◽  
A. Smallridge ◽  
S. R. Gray
Keyword(s):  
Reverse Osmosis ◽  
Membrane Surface ◽  
Scale Formation ◽  
Significant Problem ◽  
29Si Nmr ◽  
High Recovery ◽  
Desalination Plant ◽  
Nmr Study ◽  
Silica Scale ◽  
Ro Membrane

Silica scale formation on reverse osmosis (RO) membrane surface is a significant problem for operation of high recovery RO desalination plant.

scholarly journals COMBINATION OF REVERSE OSMOSIS AND ELECTRODEIONIZATION FOR SIMULTANEOUS SUGAR RECOVERY AND SALTS REMOVAL FROM SUGARY WASTEWATER

REAKTOR ◽  
2011 ◽  
Vol 11 (2) ◽  
pp. 91 ◽  
Author(s):  
I.N. Widiasa ◽  
I Gede Wenten
Keyword(s):  
Cation Exchange ◽  
Reverse Osmosis ◽  
Membrane Surface ◽  
Type I ◽  
Sugar Solution ◽  
Sugar Recovery ◽  
Permeate Flux ◽  
Strong Base ◽  
Ro Membrane ◽  
Exchange Membrane

An integrated membrane system combining reverse osmosis (RO) and electrodeionization (EDI) is used for simultaneous sugar concentration and salts removal from a synthetic dilute sugar solution as a model of sugar-containing wastewater. The RO system uses a thin film composite RO membrane (Saehan CSM, RE1812-60). Meanwhile, the EDI stack has two diluted compartments, one concentrated compartment, one anode compartment, and one cathode compartment. Commercially available cation exchange membrane (MC-3470) and anion exchange membrane (MA-3475) are used as ionic selective barriers of the EDI stack. Both diluate and concentrate compartments are filled with mixed ion exchange resins (purolite strong acid cation exchange, C-100E and strong base type I anion resins, A-400). Two different operation modes, i.e. RO-EDI and EDI-RO, were assessed. The experimental results show that the observed sugar rejection of RO membrane is more than 99.9% and there is no sugar loss in the EDI stack. This indicates that the hybrid process allows almost total sugar recovery. In addition, significant reduction of salts content from the concentrated sugar solution is obtained. From permeate flux and permeate purity points of view, however, the EDI-RO configuration seems superior to the RO-EDI configuration. It should be emphasized that scale formation on the membrane surface of the concentrate compartment side has to be controlled.

scholarly journals Industrial water reclamation using polymeric membranes – case studies involving a car manufacturer and a beverage producer

2013 ◽  
Vol 3 (4) ◽  
pp. 357-372 ◽  
Author(s):  
Bernard A. Agana ◽  
Darrell Reeve ◽  
John D. Orbell
Keyword(s):  
Membrane Surface ◽  
Oxygen Demand ◽  
Low Pressure ◽  
Polymeric Membranes ◽  
Wastewater Reclamation ◽  
Cathodic Electrodeposition ◽  
Flux Decline ◽  
Wastewater Stream ◽  
Ro Membrane ◽  
Uf Membranes

This study presents the evaluation of different polymeric membranes for the reclamation of wastewater generated by two manufacturers. Specifically, ultrafiltration (UF) membranes were evaluated for wastewater pretreatment use while nanofiltration (NF) and reverse osmosis (RO) membranes were evaluated for wastewater reclamation use. Results show that both the UF membranes used were not suitable for pretreatment of the oily wastewater stream due to the presence of suspended cathodic electrodeposition (CED) paint particles. The CED paint particles rapidly deposit on the membrane surface resulting in severe fouling and very low permeate fluxes. With respect to the metals and beverage wastewater streams, the polyvinylidine-difluoride (PVDF) UF membrane was shown to be more suitable for pretreatment than the polyacrylonitrile UF membrane. The PVDF-UF membrane had relatively lower flux decline rates, higher turbidity and higher total organic carbon reduction rates. Meanwhile, the low-pressure RO membrane proved to be suitable for wastewater reclamation of the oily and beverage wastewater streams – showing low flux decline rates, high conductivity and high chemical oxygen demand reduction rates. In terms of reclaiming the metals wastewater stream, the NF membrane proved more suitable than the low-pressure RO membrane. The NF membrane had relatively higher permeate fluxes and metals rejection rates compared to the RO membrane.

scholarly journals Surface grafting of polyvinyl alcohol (PVA) cross-linked with glutaraldehyde (GA) to improve resistance to fouling of aromatic polyamide thin film composite reverse osmosis membranes using municipal membrane bioreactor effluent

2019 ◽  
Vol 14 (3) ◽  
pp. 614-624 ◽  
Author(s):  
Godwill Kasongo ◽  
Chad Steenberg ◽  
Bradley Morris ◽  
Gracia Kapenda ◽  
Nurah Jacobs ◽  
...  
Keyword(s):  
Surface Modification ◽  
Reverse Osmosis ◽  
Membrane Bioreactor ◽  
Pure Water ◽  
Water Flux ◽  
Film Composite ◽  
Thin Film Composite ◽  
Flux Decline ◽  
Pure Water Flux ◽  
The Impact

Abstract Membrane surface modification is a favourable method to handle fouling during wastewater treatment processes. In this study, grafting of polyvinyl alcohol (PVA) through cross-link with Glutaraldehyde was applied to a thin film composite reverse osmosis membrane to enhance the resistance to flux decline. The analytical analyses attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy were performed to evaluate the impact of surface modification. Biofouling using Escherichia coli (E. coli) bacterial solution and fouling tests using a bench scale reverse osmosis system with a simulated secondary effluent from a membrane bioreactor were used to assess the impact of the surface modification initiated on antifouling properties of the membrane. It was shown that the morphological structure and the chemical properties of the membrane were altered, whereas the pure water flux slightly decreased after modification. Although a slight decrease of salt rejection was observed, the membrane resistance to fouling improved and the biofouling model used revealed the anti-biofouling capacity of the membrane. The flux decline and flux recovery ratios improved with an increase in PVA concentration. The sterilization ratio increased from 33.8 to 36.8% and the pure water flux decline decreased from 46.04 to 25.94% after modification.

Comparative Study on the Treatment of Biologically Treated Textile Effluent by Nanofiltration and Reverse Osmosis for Water Reuse

2012 ◽  
Vol 441 ◽  
pp. 584-588
Author(s):  
San Chuan Yu ◽  
Zhi Wen Chen ◽  
Mei Hong Liu ◽  
Jing Wei Zhao
Keyword(s):  
Reverse Osmosis ◽  
Water Reuse ◽  
Cross Flow ◽  
Water Shortage ◽  
Nanofiltration Membrane ◽  
Reverse Osmosis Membrane ◽  
Permeate Flux ◽  
Flux Decline ◽  
Salinity Reduction ◽  
Ro Membrane

In view of the water shortage, the increasingly severe regulations as well as the release thresholds, it is becoming increasingly necessary to reuse the textile effluents. This work concerned the treatment of textile plant effluent after conventional biological processing by membrane technology for water reuse. Desal5 DK nanofiltration (NF) membrane and BW30 reverse osmosis (RO) membrane were investigated in this study in terms of COD and color removal, salinity reduction as well as permeate flux through cross-flow permeation tests. The results showed that the Desal5 DK nanofiltration membrane exhibited higher stabilized water permeability and flux decline than the reverse osmosis membrane because of its higher porosity and tendency towards fouling. The BW30 reverse osmosis membrane reduced salinity to a great extent than the Desal5 DK nanofiltration membrane. While the nanofiltration membrane exhibited better COD removal efficiency compared to the RO membrane, possibly due to its sieving removal mechanism. The treated water with good enough quality could be recycled back into the process, thereby offering economical benefits by reducing the water consumption and wastewater treatment cost.

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.

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