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WO2003047733A1 - Membrane semi-permeable hydrophile - Google Patents

Membrane semi-permeable hydrophile Download PDF

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Publication number
WO2003047733A1
WO2003047733A1 PCT/NO2002/000470 NO0200470W WO03047733A1 WO 2003047733 A1 WO2003047733 A1 WO 2003047733A1 NO 0200470 W NO0200470 W NO 0200470W WO 03047733 A1 WO03047733 A1 WO 03047733A1
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WO
WIPO (PCT)
Prior art keywords
water
membrane
salt
skin
semi
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/NO2002/000470
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English (en)
Inventor
Thor Thorsen
Torleif Holt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STATKRAFT SF
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STATKRAFT SF
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Filing date
Publication date
Application filed by STATKRAFT SF filed Critical STATKRAFT SF
Priority to AU2002365862A priority Critical patent/AU2002365862A1/en
Publication of WO2003047733A1 publication Critical patent/WO2003047733A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/002—Forward osmosis or direct osmosis
    • B01D61/0021—Forward osmosis or direct osmosis comprising multiple forward osmosis steps

Definitions

  • the present invention concerns a semi-permeable membrane comprising one layer of a non-porous material (the diffusion skin / the membrahe skin), and one or more layers of a porous material.
  • US 4,283,913 comprises a saturated non-convective water reservoir which captures solar energy and which is used as a separation unit in combination with reverse electro dialysis or pressure retarded osmosis for energy production. From the water reservoir which partly can separate a solution, a higher concentrated stream and a less concentrated stream is passed into two chambers separated with a semi-permeable membrane. Parts of the energy which is created by permeation of the stream with lower concentration through the membrane and the subsequent mixing of the two mentioned streams are transformed into energy before the streams are returned to the water reservoir.
  • the energy potential can in principle be utilized by several technical methods where the energy can be recovered as i.e. steam pressure and stretching of polymers.
  • Two of the technical methods are using semi-permeable membranes, and these are reverse electro dialysis (energy potential as electrical DC voltage) and pressure retarded osmosis, PRO, (energy potential as water pressure).
  • the actual potential for amounts of power seems to be 25 - 50% of the water power which today has been developed in Norway.
  • Power plants based on the present invention do not lead to significant emissions into air or water. Further this form of energy is fully renewable, and is only using natural water as driving force in the same manner as conventional water power plants.
  • the object of the present invention is to allow the commercial utilization of salt power in a bigger scale.
  • An important feature of the present invention is that most of the salt gradient in the membrane is localized in the same layer - the diffusion skin - as the flow resistance. Further the present patent application also consists of a porous carrier material for the diffusion skin with no resistance worth mentioning against water transport and salt diffusion. In the present invention salt therefore does not appear in unfavourably high concentrations in parts of the membrane other than the diffusion skin. According to the present invention membranes with particular inner structures are important. Further the concentration polarization of salt at the fresh water side of the membrane skin is reduced compared to conventional membranes.
  • the pressure energy in the brackish water is in a direct manner recovered hydraulic for the pressurizing of incoming sea water. Thereby a part of the loss which ordinarily would occur in an ordinary water pump for this purpose is avoided. By avoiding this loss the PRO plant according to the present invention can be built on ground level instead of below ground level and nevertheless achieve acceptable efficiency.
  • n is the number of particles, e.g. ions, to which the salt dissociates when it is dissolved in water.
  • R is the gas constant and T is the absolute temperature.
  • the membrane skin (the diffusion skin) is a thin layer, usually on one membrane surface, which is much denser than the rest of the cross section of the membrane.
  • the characteristics of the skin are also vital for the performance of the membrane in PRO.
  • the rest of the cross section of the membrane consists of porous structures of different geometrical forms. These structures serve to support the skin and give all of the membrane the necessary mechanical strength and carry water to the skin.
  • salt will always find its way into the porous structure in the membrane, irrespective of on which side of the membrane the salt water is.
  • the salt will diffuse from salt water to fresh water because diffusion always goes towards a place with lower concentration if this is not counteracted by means of external forces such as an electrical field or by other means.
  • the fresh water flows in the opposite direction, towards the highest salt concentration. This is the principle of the natural osmotic flux.
  • the speed of the salt diffusion increases with the area of free water which is available for this. If the available water area for diffusion is reduced, the diffusion speed will decrease, and for the same reason the velocity of the water will increase.
  • the diffusion speed will always be reduced by the velocity with which the water flows through the membrane against the diffusion speed, which is analogous to walking contrary to the wind.
  • a limitation of the water area for flow and diffusion within the porous structures in the membrane will therefore with double effect reduce the possibility of the salt to get out of the structure. This will lead to accumulation of salt and high salt concentrations in the structure, also close to the skin. This will reduce the difference in salt concentration over the skin, ⁇ c s , and therefore the osmotic flux, because the osmotic pressure is reduced, see equation (3). Because both flux and pressure is reduced, the energy production will fall drastic because energy is the product of pressure and water flow, i.e. flux.
  • the object of the present invention is therefore to provide a semi-permeable membrane where the diffusion velocity of the water through the porous layer of the membrane increases.
  • the present invention therefore describes a semi-permeable membrane comprising a layer of a non-porous material (the diffusion skin / the membrane skin) and one or more layers of a porous material where the porous material comprises one or more hydrophilic materials which spontaneous are wetted with water.
  • One of the objects of the present invention is to provide a semi-permeable membrane comprising one layer of a non-porous material (the diffusion skin / the membrane skin), and one or more layers of a porous material.
  • the porous material further comprises one or more hydrophilic materials which are spontaneous wetted by water.
  • the pore volume in the porous part of the membrane is filled with more than 60% water when water flows through the membrane, preferably more than 90%.
  • the porous layer of the membrane further comprises pores with a pore size which preferably is bigger than 10 nm.
  • the wetting angle between water and the porous material is less than 60°.
  • wetted porosity in the porous part of the membrane is everywhere more than 5% within volume parts of the membrane of 10 x 10 x 10 ⁇ m (micrometers), and at least 30% in average for the whole of the porous part of the membrane.
  • the permeability for water, A is higher than 5-10 "12 m/sec Pa, and the permeability of salt, B, is less than 8-10 "7 m/s, preferably less than 3-10 "7 m/s in the present invention. Further the diffusion skin / membrane skin of the non- porous material is less than 1 ⁇ m. The thickness of the porous material is less than 200 ⁇ m.
  • porous structure in the membrane is not fully wetted with water, this means that gas (normally air) is contained within the structure. Lack of wetting means that the gas is attracted more by the membrane material than the water and the gas therefore has a tendency to fasten on the walls inside the structure.
  • the gas could occur as bubbles or more or less as a layer on the surface of the membrane material inside the structure. In both cases the gas will reduce the area of the water for flowing and diffusion. Bubbles can fill some pores in the sponge-like structure inside the membrane. The passages between these pores will often be few and more narrow than the diameters of the pores. Thereby larger parts of the structure could be blocked for water passage even if water is present within some of the pores in the structure.
  • membranes or membrane modules where the membranes comprise a thin diffusion skin with natural osmotic properties, and the rest of the membrane has an increased porosity so that salt is not collected here (the porous layer).
  • the membranes can consist of organic polymers, for example polymers based on cellulose or based on nylon.
  • the semi-permeable membrane comprised by the invention can more specific be described as a semi-permeable membrane consisting of one thin layer of a non- porous material (the diffusion skin), and one or more layers of one porous material (the porous layer), where an amount of salt containing water is in contact with one side of the diffusion skin, characterized by the porous layer having properties where a parameter B (salt permeability in the diffusion skin) fullfils the relation:
  • ⁇ is the salt permeability (m/s)
  • zlc s is the difference in salt concentration over the diffusion skin (moles/cm 3 )
  • ⁇ is the porosity
  • x is the thickness of the membrane (m)
  • J is the water flux (m/s)
  • c is the salt concentration (moles/cm 3 )
  • D is the diffusion coefficient of the salt (m 2 /s)
  • ⁇ is tortuosity
  • A m/s/Pa
  • ⁇ c s /c b exp(-d s -J/D) / ⁇ 1 + B - [(exp(d f -J/D + S-J/D) - exp(-d s -J/D)] /J ⁇ (6)
  • c b is the concentration of salt water minus the concentration of salt in the fresh water (moles/cm 3 )
  • df and d s are the thickness of the diffusion films (concentration polarization) at the fresh water side and salt water side, respectively, of the membrane
  • the value of the structure parameter S and thereby the inner structure of the membrane is decisive for its efficiency in pressure retarded osmosis.
  • the structure should have only one thin and non-porous layer wherein salt has considerably lower diffusion velocity than water. All of the other layers must be porous so that salt and water can be transported with as little resistance as possible.
  • Several porous layers can be present to give the membrane the correct mechanical properties and/or as a result of the production method. In those cases where the diffusion skin lies between two or more porous layers, or the membrane is laterally reversed in relation to fresh water and salt water, the expressions will be more complicated, but the following discussion will be valid in the same manner.
  • ⁇ c s can be expressed as a function of the "bulk" concentration of salt in the water solution outside the membrane, C b , see equation (6).
  • C b is known
  • J v and J s from equation (1 ) and (2) can be calculated.
  • A, B, S, d f and d s are the thickness of the water films outside the membrane where the salt concentration is changed in relation to the "bulk” concentrations further away. These film thickness are determined by the movement of the water in relation to the membrane and can be measured or estimated separately. In addition, they are less than S and will therefore not influence an osmosis trial as much as the parameter S.
  • the structure parameter S should have a value of 1.5-10 "3 or lower. Such a requirement as to S value makes probable that x cannot have a high value (x less than 200 ⁇ m); ⁇ cannot be too high (lower than 2.5) and ⁇ cannot have a value that is too low, i.e. higher than 50%.
  • the permeability for salt, B is less than 8-10 "7 m/s, preferably less than 3-10 "3 m/s, and the water permeability, A, is higher than 5-10 "12 m/s/Pa.
  • the thickness of the diffusion film on the side containing lesser salt and the side containing more salt is less than 60 ⁇ m, preferably less than 30 ⁇ m.
  • Membrane modules comprise flow breakers consisting of threads of polymers which are forming a net with a square or rhombic pattern. Further, several membranes are packed together to modules (rolled up to spiral membranes) where the distance between adjacent membranes are from 0.4 to 0.8 mm.
  • the channels for the salt containing feed stream are 10-50% filled with one ore more flow breaking devices consisting of threads of polymer which form a net with square or rhombic pattern.
  • the pressure in the salt containing feed stream on the membrane/membrane module is in the area from 6 to 16 bars.
  • the best efficiency in a salt power process is obtained when the pressure difference over the membrane is approximately half of the osmotic pressure.
  • parallel hollow fibers can be placed in layers so that salt water flows on the outside and fresh water on the inside of the fibers, or vice versa. The above mentioned will then be a little altered, but the pressure will be the same.
  • the skin of the membrane can possibly be located either against the sea water or the fresh water. Locating the diffusion skin against the fresh water side will have the advantage that contamination in the fresh water being more readily rejected on the membrane surface because the diffusion skin has far smaller pores compared to the porous layer. Since there is a net volume stream moving in - towards the membrane at the fresh water side, this volume stream will be able to transport different types of impurities which can lead to fouling of the membrane. On the other hand, a continuous water stream from the membrane at the sea water side will contribute to keeping the surface of the membrane clean.
  • the diffusion skin lies at the sea water side since the overpressure will press the diffusion skin against the porous layer. With the diffusion skin at the fresh water side there can be a risk that the diffusion skin loosens from the porous layer, and the membrane can be destroyed.
  • the parameters for the water permeability, A, and the salt permeability, B, are of great importance as to the performance of the membrane.
  • the thickness, porosity and tortuosity of the porous layer will not be of great importance for the energy production.
  • the thickness of this diffusion film is a critical size for the energy production by pressure retarded osmosis. This size has to be determined experimentally from transport trials where flux data are adapted to the actual model. Theoretical calculations with a more complex transport model indicate a thickness of the diffusion film of approximately 25-10 "6 m - 50-10 "6 m.
  • the thickness of the diffusion film on the surface of the membrane facing the sea water side can be reduced by increasing the flow velocity at the sea water side, and by using devices which increase the stirring of the flowing sea water (turbulence promoters). Such efforts will increase the loss by friction during the flow of the sea water, and there will be an optimum point with regard to the sea water rate through a membrane module and the shaping of the membrane module.
  • the concentration polarization of salt will be a small problem at the fresh water side in a good membrane module. This is a great advantage since the fresh water rate has to be low in parts of a good device because most of the fresh water is to be transported through the membrane and over to the sea water.
  • sea water is pressurized before it flows through the membrane module. Then the sea water together with the fresh water which has been transported through the membrane, will expand through a turbine. The pump as well as the turbine will have an efficiency of less than 1 , and energy will consequently be lost in these unit operations.
  • pressure exchange can be used.
  • pressure exchange the pressure in outgoing diluted sea water (brackish water) is used to compress incoming sea water. Only a quantity of water corresponding to the fresh water which flows through the membrane will pass through the turbine, and a far smaller turbine can therefore be used.
  • the high pressure pump for pressurizing the sea water is completely eliminated.
  • Figure 1 describes a PRO plant wherein both fresh water and sea water are fed into separate water filters prior to the streams passing each other on each side of a semi-permeable membrane.
  • a portion of the mixture of permeate and salt water with elevated pressure is passed to a turbine which is connected to a generator for the production of electric power.
  • the rest of the permeate stream is passed to a pressure exchanger where incoming sea water is pressurized.
  • the pressurized sea water is then fed into the membrane module.
  • the plant further comprises water filters for purification of a salt containing and a less salt containing feed stream, one or more semi-permeable membranes or membrane modules.
  • Figure 2 shows the stream pattern for cross-stream in a spiral module.
  • Figure 3 shows stream lines in a spiral module.
  • Figure 4 shows the build-up of the interior structure of a membrane, a non-porous layer, called diffusion skin, and one or more porous layers.
  • Figure 5 shows the relation between pressure on the one side of the membrane which is in contact with a quantity of salt containing water (the sea water side), and osmotic flux.
  • A is 10 "11 m/s/Pa and ⁇ is 3-10 "8 m/s and both are constant, it can be seen that a lower value of S gives better perfomance of the membrane.
  • Technical economic calculations show that S must have a value of 1 ,5-10 "3 m or lower.
  • Figure 7 shows concentration relations along membrane for PRO with conditions as given in table 2 (the salt concentrations at the fresh water side are hardly visible).
  • Figure 8 shows volume flux of water through the membrane for a process with conditions given in table 2.
  • Figure 9 shows that the osmotic flux is increasing with a factor of 8 after a pressure increase from 1 to 4 bar absolute.
  • the gas volume in the membrane, Vg as is then reduced to one fourth because the volume of a gas is in inverse ratio with the pressure.
  • Figure 10 The degree of hydrophobic character can be characterized by the so-called contact angle, ⁇ , between the boundary surface for water and gas where this meets the solid surface of the membrane material inside the structure. This is general knowledge which is described in textbooks of surface chemistry. The angle faces the water phase. This is illustrated in figure 10.
  • Figure 11 shows the principle and a sketch of an apparatus for osmosis trials and measurement of J v and J s . Since there are three parameters which have to be determined, at least three different measurements have to be carried out of salt and/or water flux.
  • Figures 12 and 13 show measured and modelled flux with different salt concentrations for membrane V93/5S.
  • the concentrations and rates of salt water and fresh water, respectively, to the first cell, and the sea water pressure on the membrane, are given by the input conditions, see table 2.
  • the fluxes of water and salt for these conditions are then calculated iteratively from cell to cell by means of the necessary equations.
  • the salt water rate, Q, out from the last cell defines the rate out of the process.
  • the difference between out-rate and in-rate for salt water and the pressure at the salt water side indicates the produced work.
  • the exploitation ratio of fresh water is indicated by the difference between fresh water rate in and out in relation to fresh water rate in.
  • the concentrations over the membrane from the inlet side and to the outlet are shown in figure 7 for a sea water pressure of 13 bars. Because the salt leakage through this membrane is small in this example, the increase of the salt concentration at the fresh water side is hardly noticeable, and reaches a discharge concentration of 0.5 moles/m 3 . Correspondingly the concentration polarization at the fresh water side can be fully neglected.
  • the concentration polarization at the sea water side is considerable, and gives a concentration drop just below 100 moles/m 3 .
  • concentration drop of almost 100 moles/m 3 over the porous layers.
  • the driving concentration difference over the skin of the membrane corresponds to the concentration difference between the surface of the skin against the sea water and the side of the adjacent porous layer which faces the sea water, see figure 7, and amounts to approximately 320 moles/m 3 , or barely 60% of the concentration difference between sea water and fresh water. This illustrates the importance of reducing the polarization effects. This is achieved by minimizing the thickness of the diffusion film at the sea water side (high flow velocity and good stirring), and the thickness of the porous layers.
  • Figure 8 shows the volume flux of water through the membrane as a function of dimensionless position from the inlet side. As the figure shows, the water flux changes relatively little, and the reason for this is that the driving concentration difference also is relatively constant along the membrane, see figure 7.
  • the thickness of the membrane through the porous layers is typically twice the thickness of the layer because of twisting, i.e. a relative membrane thickness of 2.0. Then the effectiveness of the structure in a 10 ⁇ m layer will be reduced from 95 to 50%. In a 20 ⁇ m layer it will be reduced from 88 to 1 %.
  • p 0 is the pressure of the environment, approximately 1 bar, and p is the system pressure.
  • a membrane is placed as a wall between to water containers with stirring.
  • the transport of water and salt throgh the membrane over time, J v and J s , can then be measured.
  • the apparatus which is used for such measurements is shown in the principal drawing in figure 11.

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  • Engineering & Computer Science (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

L'invention concerne une membrane semi-perméable composée d'une couche de matériau non poreux (couche de diffusion/peau de la membrane) et d'une ou plusieurs couches de matériau poreux, ladite couche poreuse contenant un ou plusieurs matériaux hydrophiles humidifiés spontanément par l'eau.
PCT/NO2002/000470 2001-12-07 2002-12-09 Membrane semi-permeable hydrophile Ceased WO2003047733A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002365862A AU2002365862A1 (en) 2001-12-07 2002-12-09 Hydrophile semipermeable membrane

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO20016012 2001-12-07
NO20016012A NO20016012L (no) 2001-12-07 2001-12-07 Hydrofil semipermeabel membran

Publications (1)

Publication Number Publication Date
WO2003047733A1 true WO2003047733A1 (fr) 2003-06-12

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PCT/NO2002/000470 Ceased WO2003047733A1 (fr) 2001-12-07 2002-12-09 Membrane semi-permeable hydrophile

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AU (1) AU2002365862A1 (fr)
NO (1) NO20016012L (fr)
WO (1) WO2003047733A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008137082A1 (fr) * 2007-05-02 2008-11-13 Yale University Procédé de conception de membranes utiles dans des processus membranaires osmotiques
CN102442715A (zh) * 2011-11-04 2012-05-09 国家海洋局天津海水淡化与综合利用研究所 一种压力延迟渗透/反渗透组合式脱盐方法
US8181794B2 (en) 2009-08-24 2012-05-22 Oasys Water, Inc. Forward osmosis membranes
US9156006B2 (en) 2009-12-03 2015-10-13 Yale University High flux thin-film composite forward osmosis and pressure-retarded osmosis membranes
US9186627B2 (en) 2009-08-24 2015-11-17 Oasys Water, Inc. Thin film composite heat exchangers
JP2018034149A (ja) * 2016-08-30 2018-03-08 財團法人工業技術研究院Ｉｎｄｕｓｔｒｉａｌ Ｔｅｃｈｎｏｌｏｇｙ Ｒｅｓｅａｒｃｈ Ｉｎｓｔｉｔｕｔｅ 正浸透プロセスに用いられるイオン液体およびそれを用いた正浸透プロセス

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4193267A (en) * 1977-02-25 1980-03-18 Ben-Gurion University Of The Negev Research & Development Authority Method and apparatus for generating power utilizing pressure-retarded osmosis
US4891135A (en) * 1988-01-25 1990-01-02 Hoechst Aktiengesellschaft Macroporous, asymmetric, hydrophilic polyaramide membrane
US5037555A (en) * 1990-07-09 1991-08-06 Texaco Inc. Desalination of water
EP0498348A1 (fr) * 1991-02-04 1992-08-12 Japan Gore-Tex, Inc. Membrane composite incluant une membrane de séparation
SE507377C3 (sv) * 1996-09-03 1998-06-29 Electrolux Ab Membran med osmotiska egenskaper baserat paa polyetylenglykoldiakrylat foerfarande foer framstaellning daerav samt anvaendning av detta membran vid vattenrening med omvaend osmos
US6026968A (en) * 1996-05-13 2000-02-22 Nitto Denko Corporation Reverse osmosis composite membrane
WO2002013955A1 (fr) * 2000-08-04 2002-02-21 Statkraft Sf Membrane semi-permeable, procede de production d'energie et dispositif

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4193267A (en) * 1977-02-25 1980-03-18 Ben-Gurion University Of The Negev Research & Development Authority Method and apparatus for generating power utilizing pressure-retarded osmosis
US4891135A (en) * 1988-01-25 1990-01-02 Hoechst Aktiengesellschaft Macroporous, asymmetric, hydrophilic polyaramide membrane
US5037555A (en) * 1990-07-09 1991-08-06 Texaco Inc. Desalination of water
EP0498348A1 (fr) * 1991-02-04 1992-08-12 Japan Gore-Tex, Inc. Membrane composite incluant une membrane de séparation
US6026968A (en) * 1996-05-13 2000-02-22 Nitto Denko Corporation Reverse osmosis composite membrane
SE507377C3 (sv) * 1996-09-03 1998-06-29 Electrolux Ab Membran med osmotiska egenskaper baserat paa polyetylenglykoldiakrylat foerfarande foer framstaellning daerav samt anvaendning av detta membran vid vattenrening med omvaend osmos
WO2002013955A1 (fr) * 2000-08-04 2002-02-21 Statkraft Sf Membrane semi-permeable, procede de production d'energie et dispositif

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008137082A1 (fr) * 2007-05-02 2008-11-13 Yale University Procédé de conception de membranes utiles dans des processus membranaires osmotiques
US8181794B2 (en) 2009-08-24 2012-05-22 Oasys Water, Inc. Forward osmosis membranes
US8460554B2 (en) 2009-08-24 2013-06-11 Oasys Water, Inc. Forward osmosis membranes
US9186627B2 (en) 2009-08-24 2015-11-17 Oasys Water, Inc. Thin film composite heat exchangers
US9463422B2 (en) 2009-08-24 2016-10-11 Oasys Water, Inc. Forward osmosis membranes
US9156006B2 (en) 2009-12-03 2015-10-13 Yale University High flux thin-film composite forward osmosis and pressure-retarded osmosis membranes
CN102442715A (zh) * 2011-11-04 2012-05-09 国家海洋局天津海水淡化与综合利用研究所 一种压力延迟渗透/反渗透组合式脱盐方法
JP2018034149A (ja) * 2016-08-30 2018-03-08 財團法人工業技術研究院Ｉｎｄｕｓｔｒｉａｌ Ｔｅｃｈｎｏｌｏｇｙ Ｒｅｓｅａｒｃｈ Ｉｎｓｔｉｔｕｔｅ 正浸透プロセスに用いられるイオン液体およびそれを用いた正浸透プロセス

Also Published As

Publication number Publication date
AU2002365862A1 (en) 2003-06-17
NO20016012L (no) 2003-06-10
NO20016012D0 (no) 2001-12-07

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