Potential of nanofiltration and low pressure reverse osmosis in the removal of phosphorus for aquaculture

2013 ◽  
Vol 67 (4) ◽  
pp. 831-837 ◽  
Author(s):  
C. P. Leo ◽  
M. Z. Yahya ◽  
S. N. M. Kamal ◽  
A. L. Ahmad ◽  
A. W. Mohammad
Keyword(s):  
Zeta Potential ◽  
Reverse Osmosis ◽  
Low Pressure ◽  
Separation Performance ◽  
Feed Concentration ◽  
Water Contact ◽  
Cross Sectional ◽  
High Feed ◽  
Rich Solution ◽  
Aquaculture Wastewater

Aquaculture activities in developing countries have raised deep concern about nutrient pollution, especially excess phosphorus in wastewater, which leads to eutrophication. NF, NF90, NF450 and XLE membranes were studied to forecast the potential of nanofiltration and low pressure reverse osmosis in the removal of phosphorus from aquaculture wastewater. Cross-sectional morphology, water contact angle, water permeability and zeta potential of these membranes were first examined. Membrane with higher porosity and greater hydrophilicity showed better permeability. Membrane samples also commonly exhibited high zeta potential value in the polyphosphate-rich solution. All the selected membranes removed more than 90% of polyphosphate from the concentrated feed (75 mg/L) at 12 bar. The separation performance of XLE membrane was well maintained at 94.6% even at low pressure. At low feed concentration, more than 70.0% of phosphorus rejection was achieved using XLE membrane. The formation of intermolecular bonds between polyphosphate and the acquired membranes probably had improved the removal of polyphosphate at high feed concentration. XLE membrane was further tested and its rejection of polyphosphate reduced with the decline of pH and the addition of ammonium nitrate.

Intrinsic properties and performances of NF270 and XLE membranes for water filtration

2011 ◽  
Vol 11 (2) ◽  
pp. 186-193 ◽  
Author(s):  
S. N. Diop ◽  
M. A. Diallo ◽  
C. K. Diawara ◽  
D. Cot
Keyword(s):  
Zeta Potential ◽  
Reverse Osmosis ◽  
Low Pressure ◽  
Separation Performance ◽  
Permeability Evolution ◽  
Force Microscopy ◽  
Feed Pressure ◽  
Atomic Force ◽  
Membrane Characterization ◽  
Drinking Water Production

Nanofiltration and low pressure reverse osmosis membranes are well-known in the field of drinking water production and their separation performance is very strongly related to their intrinsic characteristics. The membrane characterization (scanning electron microscopy (SEM), atomic force microscopy (AFM), zeta potential …) was realized on a NF270 and extra-low energy (XLE) membrane. SEM results of virgin NF270 and XLE membranes show that both are about the same thickness whereas that of the active layer of NF270 membrane is weaker than that of the XLE. The AFM measurements show that the roughness of the low pressure reverse osmosis membrane (XLE) is almost 20 times as high as that of nanofiltration (NF270). Zeta potential measurements showed that both membranes are negatively charged in pH (4–12) range. An increase in permeability by increasing feed pressure and temperature was also noted for the two types of membrane; but the permeability evolution for XLE membrane according to the volume factor reduction reveals a fall faster than that of NF270.

Performance of low pressure reverse osmosis membrane (LPROM) for separating mono- and divalent ions

1998 ◽  
Vol 38 (4-5) ◽  
pp. 521-528 ◽  
Author(s):  
Zaini Ujang ◽  
G. K. Anderson
Keyword(s):  
Heavy Metals ◽  
Reverse Osmosis ◽  
Metal Removal ◽  
Feed Solution ◽  
Low Pressure ◽  
Operating Conditions ◽  
Operating Pressure ◽  
Reverse Osmosis Membrane ◽  
Permeate Flux ◽  
Feed Concentration

This paper describes an investigation on the rejection of the divalent anions from ZnSO4 using LPROMs, and to establish the effect of operating pressure, feed concentration and temperature on metal removal, then to compare with the monovalent anions, ZnCl2. A bench-scale spiral wound configuration of sulphonated polysulphone low pressure reverse osmosis membrane (LPROM) was used to remove heavy metals at various operating conditions, i.e. operating conditions, solute concentrations and temperature. The results show that the higher the operating pressure the greater will be the permeate flux for heavy metals from both mono- and divalent anions. At low operating pressure however, metals from the divalent anions give a higher permeate flux than did the monovalent anions. Permeate flux in both mono- and divalent anions is shown to be subsequently increased by a decrease of the concentration of feed solution. Regarding metal removal, metals from divalent anions were rejected more effectively than monovalent anions at all levels of feed concentration.

scholarly journals REJECTION CHARACTERISTICS OF ORGANOCHLORINE PESTICIDES BY LOW PRESSURE REVERSE OSMOSIS MEMBRANE

2018 ◽  
Vol 6 (2) ◽  
Author(s):  
Woro Nastiti Utami ◽  
Rofiq Iqbal ◽  
I Gede Wenten
Keyword(s):  
River Water ◽  
Reverse Osmosis ◽  
Organochlorine Pesticides ◽  
Low Pressure ◽  
Permeate Flux ◽  
Operational Parameters ◽  
Feed Concentration ◽  
Ph Variation ◽  
Artificial Water ◽  
Reverse Osmosis Unit

The  increased  use  of  pesticides  has  led  to many  benefits  such  as  advanced  productivity and lower maintenance costs  in agriculture. On the other hand, their  adverse  effects  have  also  grown : an increase of  the risks to the ecosystem and human health. Pressure driven technique such as reverse osmosis and nanofiltration have the potentiality to remove hazardous organic micropollutants such as pesticides. The rejection characteristic of artificial water with 10 ppb concentration of endosulfan and organochlorine pesticides from upper Citarum water shed sample were investigated with a commercial low pressure reverse osmosis unit on laboratory scale. Rejection and flux were measured with a varied operational parameters ; pH, pressure, and feed concentration. Endosulfan rejection was achieved 80% with all varied operational parameters. There was a little dependence permeate flux and percent of rejection on pH. An increasing pressure caused a higher permeate flux while there was no effect of an increasing pressure to higher percentage of endosulfan rejection. An increasing feed concentration caused a lower permeate flux due to an increasing osmotic pressure.  An increasing feed concentration also result in an increasing percent of endosulfan rejection. Organochlorine pesticides found in river water sample which are lindane, aldrin, and heptachlor were all rejected 100%. This may be caused by natural organic matter present in river water and hydrophobicity. Percent rejection was constant to pressure and pH variation. Keywords : Low Pressure Reverse Osmosis, Organochlorine Pesticides, Pressure, pH, Feed Concentration

scholarly journals A New Method for a Polyethersulfone-Based Dopamine-Graphene (xGnP-DA/PES) Nanocomposite Membrane in Low/Ultra-Low Pressure Reverse Osmosis (L/ULPRO) Desalination

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 439
Author(s):  
Lwazi Ndlwana ◽  
Mxolisi M. Motsa ◽  
Bhekie B. Mamba
Keyword(s):  
Reverse Osmosis ◽  
Photoelectron Spectroscopy ◽  
Phase Inversion ◽  
Low Pressure ◽  
Inversion Method ◽  
Synthetic Approach ◽  
Operating Pressure ◽  
Cross Sectional ◽  
Drying Time ◽  
Salt Rejection

Herein we present a two-stage phase inversion method for the preparation of nanocomposite membranes for application in ultra-low-pressure reverse osmosis (ULPRO). The membranes containing DA-stabilized xGnP (xGnP-DA-) were then prepared via dry phase inversion at room temperature, varying the drying time, followed by quenching in water. The membranes were characterized for chemical changes utilizing attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The results indicated the presence of new chemical species and thus, the inclusion of xGnP-DA in the polyethersulfone (PES) membrane matrix. Atomic force microscopy (AFM) showed increasing surface roughness (Ra) with increased drying time. Scanning electron microscopy (SEM) revealed the cross-sectional morphology of the membranes. Water uptake, porosity and pore size were observed to decrease due to this new synthetic approach. Salt rejection using simulated seawater (containing Na, K, Ca, and Mg salts) was found to be up to stable at <99.99% between 1–8 bars operating pressure. After ten fouling and cleaning cycles, flux recoveries of <99.5% were recorded, while the salt rejection was <99.95%. As such, ULPRO membranes can be successfully prepared through altered phase inversion and used for successful desalination of seawater.

Analysis and calculation of the process of low-pressure reverse osmosis during recycling of hygienic water

2019 ◽  
pp. 28-36
Author(s):  
Leonid S. Bobe ◽  
Nikolay A. Salnikov
Keyword(s):  
Mass Transfer ◽  
Reverse Osmosis ◽  
Life Support ◽  
Space Station ◽  
Low Pressure ◽  
Operating Pressure ◽  
Life Support System ◽  
Cleaning Agent ◽  
The Difference ◽  
Pressure Channel

Analysis and calculation have been conducted of the process of low-pressure reverse osmosis in the membrane apparatus of the system for recycling hygiene water for the space station. The paper describes the physics of the reverse osmosis treatment and determines the motive force of the process, which is the difference of effective pressures (operating pressure minus osmotic pressure) in the solution near the surface of the membrane and in the purified water. It is demonstrated that the membrane scrubbing action is accompanied by diffusion outflow of the cleaning agent components away from the membrane. The mass transfer coefficient and the difference of concentrations (and, accordingly, the difference of osmotic pressures) in the boundary layer of the pressure channel can be determined using an extended analogy between mass transfer and heat transfer. A procedure has been proposed and proven in an experiment for calculating the throughput of a reverse osmosis apparatus purifying the hygiene water obtained through the use of a cleaning agent used in sanitation and housekeeping procedures on Earth. Key words: life support system, hygiene water, water processing, low-pressure reverse osmosis, space station.

scholarly journals Batch Reverse Osmosis Desalination Modeling under a Time-Dependent Pressure Profile

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 173
Author(s):  
Abdeljalil Chougradi ◽  
François Zaviska ◽  
Ahmed Abed ◽  
Jérôme Harmand ◽  
Jamal-Eddine Jellal ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Reverse Osmosis ◽  
Specific Energy ◽  
Energy Demand ◽  
Specific Energy Consumption ◽  
Pressure Profile ◽  
Recovery Ratio ◽  
Feed Concentration ◽  
Energetic Performance ◽  
Feed Volume

As world demand for clean water increases, reverse osmosis (RO) desalination has emerged as an attractive solution. Continuous RO is the most used desalination technology today. However, a new generation of configurations, working in unsteady-state feed concentration and pressure, have gained more attention recently, including the batch RO process. Our work presents a mathematical modeling for batch RO that offers the possibility of monitoring all variables of the process, including specific energy consumption, as a function of time and the recovery ratio. Validation is achieved by comparison with data from the experimental set-up and an existing model in the literature. Energetic comparison with continuous RO processes confirms that batch RO can be more energy efficient than can continuous RO, especially at a higher recovery ratio. It used, at recovery, 31% less energy for seawater and 19% less energy for brackish water. Modeling also proves that the batch RO process does not have to function under constant flux to deliver good energetic performance. In fact, under a linear pressure profile, batch RO can still deliver better energetic performance than can a continuous configuration. The parameters analysis shows that salinity, pump and energy recovery devices efficiencies are directly linked to the energy demand. While increasing feed volume has a limited effect after a certain volume due to dilution, it also shows, interestingly, a recovery ratio interval in which feed volume does not affect specific energy consumption.

scholarly journals Effects of Operating Parameters on Ionic Liquid Membrane to Remove Humidity in a Green Continuous Process

Membranes ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 65
Author(s):  
Xueru Yan ◽  
Alexandre Favard ◽  
Stéphane Anguille ◽  
Marc Bendahan ◽  
Philippe Moulin
Keyword(s):  
Ionic Liquid ◽  
Flow Rate ◽  
Continuous Process ◽  
Hybrid Process ◽  
Absolute Pressure ◽  
Mechanical Resistance ◽  
Operating Parameters ◽  
Separation Performance ◽  
Feed Concentration ◽  
Time Operation

Membrane processes are promising methods to separate gases from feed streams without phase changing. A hybrid process, the combination of ionic liquids with a ceramic membrane (ILM), has been developed for humidity removal in a green continuous process. This new concept provides a more efficient and available ionic liquid (IL)-based membrane regeneration process, which just switches the moist feed stream to dry air. Furthermore, the ILM presents high stability and mechanical resistance during long-time operation. In addition, the influences of several operating parameters, including flow rate, temperature, absolute pressure, and feed concentration on process efficiency were investigated. The lower inlet flow rate was found to be favorable for drying humid air. Moreover, when the pressure increased, the mass of absorbed water was increased, while the feed concentration had no significant effects on the membrane separation performance. However, the operating temperature had a great effect on humidity removal. It is necessary to note that the processes at room temperature can limit the energy consumption. The absorbing process of ILM remained efficient after several absorption desorption cycles. Therefore, the new ILM hybrid process that has been developed has great potential for consecutive humidity removal processes.

Dehydration of water/pyridine mixtures by pervaporation using cellulose acetate/ polyacrylonitrile blend membrane

2011 ◽  
Vol 63 (8) ◽  
pp. 1695-1700 ◽  
Author(s):  
J. H. Lv ◽  
G. M. Xiao
Keyword(s):  
Cellulose Acetate ◽  
Separation Factor ◽  
Experimental Results ◽  
Separation Performance ◽  
Permeation Flux ◽  
Feed Concentration ◽  
Blend Membrane ◽  
Pyridine Solution ◽  
Operation Temperature

Cellulose acetate/ polyacrylonitrile (CA/PAN) membranes were prepared and used to separate pyridine / water mixtures by pervaporation. The membranes were characterized through SEM. The effects of feed concentration, operation temperature and downstream pressure on the separation performance were evaluated. Experimental results indicated the increase of operation temperature could raise the permeation flux and the separation factor, while increasing feed concentration and downstream pressure would raise the separation factor and decrease the permeation flux. Under the conditions that pyridine solution was 99 wt.%, operation temperature was 323 K and downstream pressure was 20 mmHg, the CA/PAN blend membrane showed its best separation performance that the permeation flux was 56 · g · m−2 h−1 and the separation factor was 182.

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