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.

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 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 Silica scale mitigation for high recovery reverse osmosis of groundwater for a mining process

Desalination ◽  
2014 ◽  
Vol 340 ◽  
pp. 49-58 ◽  
Author(s):  
P. Sanciolo ◽  
N. Milne ◽  
K. Taylor ◽  
M. Mullet ◽  
S. Gray
Keyword(s):  
Reverse Osmosis ◽  
High Recovery ◽  
Silica Scale

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 Seawater reverse osmosis membrane fouling causes in a full scale desalination plant; through the analysis of environmental issues: raw water quality

2020 ◽  
Vol 7 (2) ◽  
pp. 119-126
Author(s):  
Leila Rezaei ◽  
Mohsen Dehghani ◽  
Amir Hesam Hassani ◽  
Vali Alipour
Keyword(s):  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Field Analysis ◽  
Residual Chlorine ◽  
Stress Tests ◽  
Visual Evaluation ◽  
Desalination Plant ◽  
Improper Use ◽  
Metallic Compounds

Background: Membrane clogging is one of the most important problem for desalination plant operators in Iran, therefore, this study was conducted to investigate the main causes of this problem using field analysis. Methods: In this study, six continuous membranes in a reverse osmosis (RO) pressure vessel under the 33-month service period (April 2017 to November 2019) were selected. The membranes were analyzed through visual evaluation of the outer and inner membrane surface, analyzing the damages and physical harms, oxidative stress tests, iron spot test, fouling chemical analysis using loss on ignition (LOI) tests, X-ray fluorescence (XRF), and Fourier-transform infrared (FTIR) spectroscopy. Results: Particle size distribution in raw seawater (EC = 55 000 µs/cm, turbidity = 11 NTU) was 66.4% smaller than 1 µ and 28.3% between 1 to 1.9 µm. Physical damages were not seen on the membranes but telescopic damages were observed which was due to membrane fouling. Removal efficiencies of turbidity and silt density index (SDI) were 84% and 18%, respectively. Membrane oxidation was also seen. Most of the sediments compositions on the membranes were SiO2 , Al2 O3 , MgO, and Fe2 O3 . Biological fouling was detected on the membranes surface. Conclusion: Inaccurate use of chlorine neutralizer caused the residual chlorine to be present in the membrane entering water, which damaged the membrane. Accumulation of clogging agents on membrane surface showed malfunction of pretreatment function, therefore, revision of design and operation of units is necessary. Biological fouling is due to non-effective pre-chlorination of drinking water. Metallic compounds sedimentation on the membrane is due to improper use of anti-fouling chemicals. High SDI in the influent shows the need to change the cartridge filters.

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 An analysis of the effects of pressure-assisted osmotic backwashing on the high recovery reverse osmosis system

2019 ◽  
Vol 69 (3) ◽  
pp. 298-318 ◽  
Author(s):  
Naveenkumar Ashok Yaranal ◽  
Sneha Kumari ◽  
Selvaraju Narayanasamy ◽  
Senthilmurugan Subbiah
Keyword(s):  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Low Cost ◽  
Water Pressure ◽  
Operating Parameter ◽  
High Recovery ◽  
Cleaning Efficiency ◽  
Membrane Cleaning ◽  
Number Of Leaves ◽  
Ro Membrane

Abstract The low cost simplified method for implementation of pressure-assisted osmotic (PAO) backwash (BW) for spiral wound reverse osmosis (RO) membrane module is presented in this work. The effect of membrane design and an operating parameter concerning the efficiency of PAO membrane BW is analyzed. The following design and operating parameters are considered in this study: (i) spacer thickness, (ii) dimension of the permeate channel, (iii) number of leaves, and (iv) BW water pressure. The performance of PAO BW with respect to membrane cleaning efficiency is analyzed for three different high recovery RO systems by purifying 1,500 liters of water. The membrane cleaning efficiency is measured by examining the rate of permeate quality and quantity decline using ASTM D4516 method. Finally, to quantify the membrane fouling with respect to different high recovery configurations, the thickness, and composition of foulants present in the used membrane's surface are measured by using field emission scanning electron microscope with energy dispersive X-ray (FESEM-EDX). The result concludes that the RO membrane operated at high recovery with PAO BW is found to have less fouling deposits than membrane without PAO BW.

Novel Spacer Design Using Topology Optimization in a Reverse Osmosis Channel

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Seungjae Oh ◽  
Semyung Wang ◽  
Minkyu Park ◽  
Joon Ha Kim
Keyword(s):  
Topology Optimization ◽  
Reverse Osmosis ◽  
Membrane Surface ◽  
Navier Stokes ◽  
Permeate Flux ◽  
Membrane Channel ◽  
Reference Models ◽  
Membrane Surfaces ◽  
Ro Membrane ◽  
And Performance

The objective of this study is to design spacers using topology optimization in a two-dimensional (2D) crossflow reverse osmosis (RO) membrane channel in order to improve the performance of RO processes. This study is the first attempt to apply topology optimization to designing spacers in a RO membrane channel. The performance was evaluated based on the quantity of permeate flux penetrating both the upper and lower membrane surfaces. Here, Navier–Stokes and convection-diffusion equations were employed to calculate the permeate flux. The nine reference models, consisting of combinations of circle, rectangle, and triangle shapes and zig-zag, cavity, and submerged spacer configurations were then simulated using finite element method so that the performance of the model designed by topology optimization could be compared to the reference models. As a result of topology optimization with the allowable pressure drop changes in the channel, characteristics required of the spacer design were determined. The spacer design based on topology optimization was then simplified to consider manufacturability and performance. When the simplified design was compared to the reference models, the new design displayed a better performance in terms of permeate flux and wall concentration at the membrane surface.

Grafted cellulose acetate reverse osmosis membrane using 2-acrylamido-2-methylpropanesulfonic acid for water desalination

2016 ◽  
Vol 16 (4) ◽  
pp. 1046-1056 ◽  
Author(s):  
Ashraf Morsy ◽  
Shaker Ebrahim ◽  
El-Refaie Kenawy ◽  
Tarek Abdel-Fattah ◽  
Sherif Kandil
Keyword(s):  
Cellulose Acetate ◽  
Reverse Osmosis ◽  
Membrane Surface ◽  
Water Flux ◽  
Contact Angles ◽  
Water Desalination ◽  
Salt Rejection ◽  
Morphological Studies ◽  
Phase Inversion Technique ◽  
Ro Membrane

Reverse osmosis (RO) membranes based on cellulose acetate (CA), were prepared using a phase inversion technique. To improve the hydrophilicity, salt rejection and water flux of these membranes, a novel grafting of 2-acrylamido-2-methylpropanesulfonic acid (AMPSA) was added on the top surface of the CA-RO membranes. The grafted CA-RO membranes were characterized by Fourier transform infrared spectroscopy (FTIR), contact angle, and scanning electron microscopy techniques. It was found that the contact angles were 58° and 45° for pristine CA and 15 wt% grafted CA-RO membranes, respectively, which suggest an increase in the membrane surface hydrophilicity after grafting. The morphological studies of the surface of the pristine CA-RO membrane revealed a typical ridge-and-valley morphology and displayed a relatively high surface roughness of 337 nm, and a significant decrease at 15 wt% of grafted CA-RO membrane to 7 nm. The effect of the grafting percentages of AMPSA on the water flux and salt rejection was studied using a cross flow RO unit. The salt rejection and water flux of the grafted CA-RO membrane with 15 wt% were 99.03% and 6 L/m2h, respectively.

Permeability decline in nanofiltration/reverse osmosis membranes fed with municipal wastewater treated by a membrane bioreactor

2013 ◽  
Vol 67 (9) ◽  
pp. 1994-1999 ◽  
Author(s):  
Katsuki Kimura ◽  
Naoko Ogawa ◽  
Yoshimasa Watanabe
Keyword(s):  
Organic Matter ◽  
Reverse Osmosis ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Membrane Surface ◽  
Chemical Cleaning ◽  
Filtration Resistance ◽  
Cake Layer ◽  
Total Filtration ◽  
Ro Membrane

Decline in the permeability in nanofiltration (NF)/reverse osmosis (RO) membranes that filtered effluents from a membrane bioreactor (MBR) treating municipal wastewater was investigated in this study. Four different 2-inch spiral-wound NF/RO membrane elements were continuously operated for 40 days. The results showed that the amount of deposits on the membrane surface did not affect the degree of permeability decline. Laboratory-scale filtration tests with coupons obtained from the fouled membranes also revealed that the contribution of the gel/cake layer to total filtration resistance was minor. Rather, constituents that were strongly bound to the membranes were mainly responsible for permeability decline. Chemical cleaning of the fouled membranes carried out after removal of the cake showed that silica played an important role in the decline in permeability. A considerable amount of organic matter which was mainly composed of carbohydrates and proteins was also desorbed from the fouled membranes.

Sign in / Sign up

Export Citation Format

Share Document