WO2017155298A2 - Procédé de dessalement sans électricité exploitant le phénomène de polarisation de concentration d'ions en capillaire et structure de dessalement non électrique - Google Patents

Procédé de dessalement sans électricité exploitant le phénomène de polarisation de concentration d'ions en capillaire et structure de dessalement non électrique Download PDF

Info

Publication number
WO2017155298A2
WO2017155298A2 PCT/KR2017/002498 KR2017002498W WO2017155298A2 WO 2017155298 A2 WO2017155298 A2 WO 2017155298A2 KR 2017002498 W KR2017002498 W KR 2017002498W WO 2017155298 A2 WO2017155298 A2 WO 2017155298A2
Authority
WO
WIPO (PCT)
Prior art keywords
desalination
capillary
porous structure
ion concentration
ion
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/KR2017/002498
Other languages
English (en)
Korean (ko)
Other versions
WO2017155298A3 (fr
Inventor
김성재
박성민
이효민
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.)
SNU R&DB Foundation
Original Assignee
Seoul National University R&DB Foundation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from KR1020170027605A external-priority patent/KR101903596B1/ko
Application filed by Seoul National University R&DB Foundation filed Critical Seoul National University R&DB Foundation
Publication of WO2017155298A2 publication Critical patent/WO2017155298A2/fr
Publication of WO2017155298A3 publication Critical patent/WO2017155298A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers

Definitions

  • the present invention relates to a no-power desalination method and a no-power desalination structure using the capillary ion concentration polarization phenomenon. More specifically, the present invention relates to a non-powered desalination method and a non-powered desalination structure using a capillary ion concentration polarization phenomenon capable of spontaneous desalination without an external driving source.
  • micro / nano fluid-based devices have attracted much attention in applications related to energy and environment beyond the conventional bio systems such as diagnostic systems and drug delivery.
  • desalination mechanisms appearing around the nanoporous structure to which electric fields are applied are identified through current-voltage characteristics, micro / nano fluid-based water purification, desalination and desalination systems have been newly pioneered.
  • micro / nano fluid-based unit desalination cells can be integrated to develop small desalination devices and can be applied to portable desalination devices or portable desalination plants.
  • Ion concentration polarization is one of the main mechanisms in the desalination mechanisms of small desalination / purifiers.
  • Ion concentration polarization refers to a phenomenon in which ions in the electrolyte are separated across the ion selective permeable membrane when an electric field is applied across the ion selective permeable membrane.
  • an ion depletion zone in which ions are lowered around the anode and an ion enrichment zone in which ion concentration is increased around the cathode are generated. Based on these phenomena, studies are being conducted to fabricate ion-selective permeable membranes using bipolar electrodes and nanoporous particles, to fabricate paper-based microchannels, and to capture and concentrate biomaterials.
  • the desalination method using ion concentration polarization not only effectively removes salt from high concentrations of seawater, but also removes bacteria and heavy metals at once, but requires a strong electric field around the ion-selective permeable membrane. Therefore, there is a problem that the power consumed also increases according to the desalination efficiency. Therefore, there is an urgent need for a technique for desalination using minimal power.
  • the present invention focuses on the above-described problems and the desalination mechanism of mangroves, and spontaneous desalination at the boundary between the nanoporous membrane and the brine and nanoelectrodynamic analysis of the phenomenon, enables spontaneous desalination without an external driving source.
  • An object of the present invention is to provide a non-powered desalination method using a capillary ion concentration polarization phenomenon.
  • an object of the present invention is to provide a non-powered desalination structure using a capillary ion concentration polarization phenomenon that can be implemented in a simple structure, miniaturized, portable.
  • CICP capillarity ion concentration polarization
  • the power to infiltrate into the porous structure is provided by the capillary force of the capillary tube included in the porous structure, there is provided a powerless desalination method.
  • the ion depletion zone is formed by generating the capillary ion concentration polarization phenomenon in a region adjacent to the desalination target fluid and the porous structure, and the inside of the capillary of the porous structure is formed. And fresh water may be collected between the porous structure and the ion depletion region boundary.
  • the size of the ion depletion region may be 1 ⁇ m to 10,000 ⁇ m.
  • the porous structure may be a hydrogel.
  • the hydrogel may include 2-hydroxyethyl methacrylate (HEMA) and acrylic acid (AA).
  • HEMA 2-hydroxyethyl methacrylate
  • AA acrylic acid
  • the time for which the capillary ion concentration polarization is maintained may increase.
  • the absorption parameter of the porous structure Is defined as ( ⁇ d cap ) / (4D ⁇ ), where ⁇ is the surface tension, d cap is the diameter of the capillary, ⁇ is the dynamic viscosity of the fluid, and the larger the absorption parameter, the greater the capillary ion concentration polarization.
  • the time that is maintained can be increased.
  • the time for maintaining the capillary ion concentration polarization may increase.
  • the porous structure can be confined in a microchannel to prevent swelling due to salting of the ions.
  • the porous structure is formed in the form of particles, a plurality of the particles are concentrated to form a desalination structure, the ion depletion region is formed in the space between the particles, the desalination structure Fresh water can be collected inside.
  • a non-powered desalination structure comprising a porous structure having a selective permeability to ions, the porous structure includes a plurality of capillaries, selective permeability of the desalination target fluid
  • a non-powered desalination structure in which ions having are imbibition by capillary force of the capillary to induce capillarity ion concentration polarization (CICP).
  • CICP capillarity ion concentration polarization
  • the ion depletion zone is formed by generating the capillary ion concentration polarization phenomenon in a region adjacent to the desalination target fluid and the porous structure, and the inside of the capillary of the porous structure is formed. And fresh water may be collected between the porous structure and the ion depletion region boundary.
  • a plurality of porous structures in the form of particles may be concentrated, and ion depletion regions may be formed in the spaces between the plurality of porous structures, so that fresh water may be collected in the desalination structure.
  • FIG. 1 is an exemplary schematic diagram of a micro / nano fluid-based capillary ion concentration polarization apparatus for explaining the principle of a non-powered desalination method using a capillary ion concentration polarization phenomenon (CICP) according to an embodiment of the present invention.
  • CICP capillary ion concentration polarization phenomenon
  • FIG. 2 is an exemplary photograph of a process of implementing the apparatus of FIG. 1 and the implemented apparatus.
  • 3 and 4 are photographs showing the flow of the fluid by the porous structure according to an embodiment of the present invention.
  • FIG. 5 is a graph representing the length of an imbibition as a function of time and a graph of the rate of dyeing according to one embodiment of the present invention.
  • FIG. 6 is a confocal micrograph showing that fluorescent material collects at the edge of a channel according to an embodiment of the present invention.
  • FIG. 7 is a view showing a spontaneous fresh water process in (a) a centrally connected device, (b), (c) a terminally connected device according to an embodiment of the present invention.
  • FIG. 8 is a photograph showing an ion concentration depletion phase and an ion concentration recovery phase in the capillary ion concentration polarization phenomenon (CICP) of the FIG. 7 device.
  • CICP capillary ion concentration polarization phenomenon
  • FIG. 9 is a graph illustrating cation concentration distribution when ion selectivity is located at the right boundary in (a) ion concentration depletion step and (b) ion concentration recovery step according to an embodiment of the present invention.
  • 10 is a graph showing (a) the lowest concentration change of cations according to the absorption parameter and (b) the lowest concentration change of cations according to the stolen equilibrium concentration according to an embodiment of the present invention.
  • FIG. 11 is a schematic view illustrating a non-powered desalination structure formed by densely forming a plurality of particle-shaped porous structures according to an exemplary embodiment of the present invention.
  • the present invention is characterized by using ion selectivity and capillary force of a porous structure such as a hydrogel made of nanomesh, as a power source, unlike the existing desalination technology applying an electric field around the nanoporous membrane.
  • a porous structure such as a hydrogel made of nanomesh
  • the nanoporous structure As the nanoporous structure absorbs the fluid by capillary force, the nanoporous structure generates an ionic flux, through which ion concentration polarization occurs.
  • this phenomenon is called “Capillarity ion concentration polarization” (CICP), and the capillary ion concentration polarization phenomenon is described as a new concept.
  • CICP Capillarity ion concentration polarization
  • FIG. 1 is an exemplary schematic diagram of a micro / nano fluid-based capillary ion concentration polarization apparatus for explaining the principle of a non-powered desalination method using a capillary ion concentration polarization phenomenon (CICP) according to an embodiment of the present invention.
  • FIG. 2 is a process of implementing the apparatus of FIG. 1 (FIG. 3A) and an example photograph of the implemented apparatus (FIGS. 3B and 3C).
  • 1 and 2 are only one exemplary design for explaining the CICP, it should be noted that the no-power desalination method and the no-power desalination structure of the present invention are not necessarily limited to this design.
  • Figs. 1 and 2 illustrate the principle of CICP as an example of a microchannel, but it is noted that CICP may also occur in a macro environment.
  • the central / end connected device may include a micro channel 10 and a porous structure 20.
  • the micro channel 10 may be provided at both ends with an inlet for injecting a desalination target fluid 12 for desalination.
  • the microchannel 10 may have a long shape in one direction so that the desalination target fluid 12 has a structure that is easy to move along the path.
  • the desalination target fluid 12 is representative of seawater containing salts, but may also include blood containing red blood cells / white blood cells, wastewater containing heavy metals, and the like.
  • the porous structure 20 may be disposed on one surface (lower surface) of the micro channel 10 in a direction perpendicular to the length direction of the micro channel 10.
  • the porous structure 20 may be arranged to intersect at the central portion of the microchannel 10 in a centrally connected device (see FIGS. 1A and 3B).
  • the porous structure 20 may be disposed in the vertical direction at the distal end of the microchannel 10 (see FIGS. 1B and 3C).
  • the centrally connected device has the advantage of being easy to inject or flush out the sample (desalination target fluid 12), but has the effect of residual flow, and the terminally connected device is difficult to inject the sample but can effectively suppress the residual flow.
  • the porous structure 20 may have selective permeability to ions. In addition, it may include a plurality of capillaries (not shown) that can cause the capillary force therein.
  • the porous structure 20 formed in the form of a membrane is used to confine the porous structure 20 in the channel, but there is no limitation in shape, and in the form of particles, spheres, etc. It may be formed.
  • the porous structure 20 is a material in which nano / micro pores are formed on the surface and the inside thereof, and a hydrogel may correspond thereto.
  • the pores are formed in the form of capillaries and can suck fluid.
  • the porous structure 20 is monomer 2-hydroxyethyl methacrylate (HEMA), acrylic acid (AA), cross-linker ethylene glycol dimethacrylate (EGDMA), photoinitiator 2,2-dimethoxy Hydrogels via a mixture of -2 phenyl-actophenone (DMPA) can be used.
  • HEMA 2-hydroxyethyl methacrylate
  • AA acrylic acid
  • EGDMA cross-linker ethylene glycol dimethacrylate
  • DMPA photoinitiator 2,2-dimethoxy Hydrogels via a mixture of -2 phenyl-actophenone
  • the mixing ratio (HEMA: AA: EGDMA: DPMA) is a mass ratio of 32.51: 6: 0.41: 1.25 (5: 1 hydrogel), or 32.51: 18: 0.41: 1.25 (5: 3 hydrogel).
  • the porous structure 20 may use Nafion, capillary bundles, or the like, as long as it has a selective permeability to ions and at the same time has a capillary force for sucking fluid, including a plurality of capillaries. It may be.
  • the capillary of the porous structure 20 may be formed in a narrow and long shape such that the capillary force may be induced by a capillary phenomenon.
  • Capillary phenomenon is the absorption of liquid along the capillary tube. If the attraction force between the water molecule and the capillary is stronger than the cohesive force between the water molecules, a thin water molecule film is formed through the capillary tube. It will suck up the water. The water rises to a height where the weight of the attracted water column is equal to the attraction between the capillaries.
  • Such capillary force is observed, for example, when water penetrates into an absorbent paper or cloth on its own, and water or nutrients absorbed from the root of a plant spread through the whole plant.
  • Ion concentration polarization is one of the electrochemical transfer phenomena observed around nanostructured structures. It is theoretically known that when the thickness of the electric double layer is similar to the size of the nanomembrane, the double layer overlaps inside the nanomembrane to show single ion permeability. As the charges such as wall charges do not pass through the nanomembrane due to diffusion and drift force, only ions having opposite charges to the wall charge pass through, resulting in depletion and excess of ions at the nanomembrane interface. The strong electrical repulsive force is applied between the ions that do not pass through the nano-membrane, and both cations and anions are affected, and a concentration gradient occurs in the diffusion boundary layer on the surface of the ion-exchange membrane. It is called a phenomenon.
  • Ion concentration polarization may form an ion depletion zone in which the concentration of ions is significantly reduced.
  • This ion depletion region may be comprised of freshwater components as the concentration of ions and many other inorganic salts is reduced.
  • the ion depletion region may be composed of fresh water components excluding salts included in sea water, for example, Cl ⁇ , Na + , as well as many inorganic salts.
  • ion concentration polarization is a phenomenon that occurs when an ionic substance, for example, an inorganic ion, an organic acid, an amino acid, or the like is separated by using an ion exchange membrane, and is mainly driven by electromotive force as a driving force of mass transfer. I use it.
  • the desalination method / apparatus of the present invention may cause the ion concentration polarization phenomenon by using the capillary force and ion selective permeation characteristics of the porous structure 20 as a transfer mechanism of ions.
  • CICP capillarity ion concentration polarization
  • the size of the ion depletion region (ion depletion layer) formed by the capillary ion concentration polarization may vary depending on the structure in which the nanoporous structure 20 such as the microchannel structure and the macro structure and the desalination target fluid 12 are in contact with each other. However, it may have a size of about 1 ⁇ 10,000 ⁇ m.
  • the non-powered desalination method of the present invention comprises the steps of: (a) contacting the desalination target fluid 12 with the porous structure 20 having selective permeability to ions, (b) the selective permeability of the desalination target fluid 12 Imbibition of ions having a porosity into the porous structure 20 to induce capillarity ion concentration polarization (CICP), and a force for salivating ions having selective permeability into the porous structure 20 Is characterized in that by the capillary force of the capillary tube included in the porous structure (20).
  • CICP capillarity ion concentration polarization
  • Capillary ion concentration polarization occurs in a region where the desalination target fluid 12 and the porous structure 20 are adjacent to form an ion depletion zone, and the inside of the capillary and the porous structure 20 of the porous structure 20 is formed. And fresh water is collected between and the ion depletion region boundary (P).
  • the non-powered desalination structure of the present invention is a non-powered desalination structure including a porous structure 20 having a selective permeability to ions, the porous structure 20 includes a plurality of capillaries, the desalination target fluid 12 Ions having selective permeability are imbibitioned by capillary force of the capillary to induce capillarity ion concentration polarization (CICP).
  • CICP capillarity ion concentration polarization
  • CICP capillary ion concentration polarization phenomenon
  • the primary material for forming channels in CICP devices is polydimetiyl-siloxane (PDMS, Sylgard 184 Silicone elastomer kit, Dow Corning, USA).
  • the final device consists of two layers: the lower layer is filled with hydrogel and the upper layer is made up of microchannels for brine.
  • a silicon master lithographically lithography with a SU8 photosensitizer is used to form a channel of 400 ⁇ m ⁇ 50 ⁇ m ⁇ 16 mm in the lower layer and 100 ⁇ m ⁇ 15 in the upper layer.
  • a channel of ⁇ m (depth) ⁇ 10 mm (length) is formed.
  • PDMS and a curing agent were mixed at a ratio of 10: 1, poured into the master, and heated to an oven at 75 ° C. for 4 hours to complete.
  • the hydrogel mixture is then injected into the formed microchannels.
  • the hydrogel mixture is composed of monomer 2-hydroxyethyl methacrylate (HEMA), acrylic acid (AA), cross-linker ethylene glycol dimethacrylate (EGDMA), photoinitiator 2,2-dimethoxy-2 phenyl-actophenone (DMPA) Mixtures can be used.
  • HEMA monomer 2-hydroxyethyl methacrylate
  • AA acrylic acid
  • EGDMA cross-linker ethylene glycol dimethacrylate
  • DMPA photoinitiator 2,2-dimethoxy-2 phenyl-actophenone
  • the mixing ratio (HEMA: AA: EGDMA: DPMA) is a mass ratio of 32.51: 6: 0.41: 1.25 (5: 1 hydrogel), or 32.51: 18: 0.41: 1.25 (5: 3 hydrogel). have.
  • the mixing ratio of HEMA and AA plays a role in influencing capillary ion concentration polarization.
  • the polymerization is performed by irradiating the UV (WUV-L50, Daihan Scientific, Korea) at about 3 mW / cm 2 for about 8 minutes.
  • the hydrogel polymerized by the increased adhesion due to the plasma treatment is filled in the PDMS mold. Filled sewage gels are initially hard, brittle and dry, whereas when CICP develops and retains moisture, they form a flexible and tough gel.
  • microchannel-patterned PDMS is bonded onto the hydrogel filled PDMS using oxygen plasma. Then, saline water (desalination target fluid 12) is injected into the microchannel and brought into contact with the hydrogel.
  • FIG. 2B When driving the CICP phenomenon, two designs, a centrally connected device (FIG. 2B) and a terminally connected device (FIG. 2C), were applied.
  • Hydrogels generally have a property of swelling, so that the surface tension is changed by swelling and osmo-poro-elastic, which absorbs fluid.
  • the nature of the gel was minimized by confinement and confinement in the microchannel.
  • the hydrogel trapped in the micro-channel absorbs the fluid but maintains little swelling.
  • the hydrogel absorbs water, and only the capillary force is considered.
  • 3 and 4 are photographs showing the flow of the fluid 12 by the porous structure 20 according to an embodiment of the present invention.
  • the total volume V water of the desalination target fluid 12 disappeared by the capillary force can be estimated as the velocity of the particles.
  • the hydrogel has a property to fluoresce itself before absorbing the aqueous solution. Then, when the aqueous solution is absorbed, the fluorescence is gradually lost from the absorbed portion, and the volume (V wet ) in which the fluid is immersed in the hydrogel for a predetermined time can be calculated by tracking the interface. Through this, (V water / V wet ) value was calculated to be about 0.1, and this was used as an important parameter in the theoretical calculation.
  • the aqueous solution absorbed in the hydrogel is desalted, and can be seen collected in the hydrogel (nano / micro pores).
  • FIG. 5 is a graph representing the length of an imbibition as a function of time and a graph of the rate of dyeing according to one embodiment of the present invention.
  • the conventional ion concentration polarization is formed by an external electromotive force, and creates an ion depletion region where the ion is extremely low on the anode side of the nanochannel, and an ion saturation region where ions accumulate on the cathode side.
  • These mechanisms are generated by electric fields and electrodynamic flows, and the important point is that ion concentration polarization can act as an electric filter.
  • the virtual wall pushes charged particles out of the ion depletion region and serves as a mechanism for seawater desalination / purification or for trapping biomolecules.
  • ion concentration polarization can be generated by other methods than by applying an electric field from the outside. That is, the ion concentration polarization phenomenon should occur in the capillary ion concentration polarizer.
  • FIG. 6 is a confocal micrograph showing that fluorescent material gathers at the edge of channel 10 in accordance with one embodiment of the present invention.
  • fluorescent materials gather at the corners of the microchannel 10. This may be seen as a phenomenon in which the fluorescent material is pushed upward of the channel 10 while the ion concentration polarization occurs initially.
  • ion concentration polarization is formed by ion depletion region within a few seconds by the application of an external strong electric field, the fluorescent material is pushed directly to the outside of the channel.
  • the capillary ion concentration polarization phenomenon since the generation rate is very slow, it can be observed that the fluorescent material initially collects in the upper corner portion of the channel 10. If there is no ion concentration polarization, since the fluorescent material is not pushed out, the fluorescence should appear throughout the channel 10. However, in the present invention, since the capillary ion concentration polarization phenomenon is induced, only the upper edge of the channel 10 Fluorescence may appear.
  • FIG. 7 is a view showing a spontaneous fresh water process in (a) a centrally connected device, (b), (c) a terminally connected device according to an embodiment of the present invention.
  • Figure 7 (a) after 5 hours in a hydrogel of HEMA: AA 5: 1
  • Figure 7 (b) after 35 hours in a hydrogel of HEMA: AA 5: 1
  • the ion depletion region in the capillary ion concentration polarization phenomenon requires a long time of several hours or more.
  • 7 shows an optical image of the change in brightness of the fluorescent material. Each picture represents a picture when the ion depletion region is maximized.
  • capillary ion concentration polarization has a linear form or a more linear concentration form, which is a shape that appears only in capillary ion concentration polarization.
  • the concentration of the fluorescent material around the hydrogel decreases by about 80 to 90%. I thought that the fluorescent material would behave similar to the behavior of the ions, so the ion concentration would also decrease.
  • the ion concentration polarization is formed asymmetrically, which is considered to be a difference in the experimentally generated pressure distribution on both sides of the channel.
  • Is a dimensionless spatial coordinate for the distance away from the ion-selective permeable membrane Represents the dimensionless ionic flux of cations passing into the permeable membrane.
  • the ion depletion region is formed asymmetrically because in the case of the centrally connected device, residual flow is generated at both ends of the hydrogel according to the height difference between the solutions at both ends.
  • the speed of the total flow on the right increases and the speed of the total flow on the left decreases.
  • Theoretical analysis shows that ion depletion regions are better formed at lower peclet counts than at high peclet counts. Since the Peclet number is related to the velocity of the flow, it can be interpreted that the left side of the ion depletion region is stronger than the right side.
  • FIG. 8 is a photograph showing an ion concentration depletion phase and an ion concentration recovery phase in the capillary ion concentration polarization phenomenon (CICP) of the FIG. 7 device.
  • the capillary ion concentration polarization phenomenon in the CICP system is formed and maintained over several hours or tens of hours depending on the composition of the porous structure 20 and the structure of the microchannel 10.
  • the ion depletion region disappears and returns to its original concentration. This phenomenon did not occur in the conventional ion concentration polarization phenomenon, because the existing ion concentration polarization is generated by applying a voltage, it is maintained until the external power off.
  • (A), (b), (c) of FIG. 8 are photographs taken at 1, 7 and 8 hour intervals, respectively. Note that the rate at which the concentration is restored in the ion concentration recovery step and the rate at which the ion depletion region is formed are different.
  • u imb Is the absorption rate, S is the absorption parameter, and t is the time.
  • u imb induces capillary ion concentration polarization, which is proportional to t -0.5 . In other words, the rate of absorption decreases with time. Details on this will be described later.
  • FIG. 9 is a graph illustrating cation concentration distribution when ion selectivity is located at the right boundary in (a) ion concentration depletion step and (b) ion concentration recovery step according to an embodiment of the present invention.
  • the behavior of the capillary ion concentration polarization over time has been studied.
  • the ion concentration depletion step using the selected parameters, which will be described later, is shown in FIG. You can think of it as ⁇ 0.4. However, after this step, the ion concentration depletion step is changed to the ion concentration recovery step as shown in Fig. 9 (b), because the absorption rate decreases.
  • the rate of absorption decreases gradually in both the ion concentration depletion step and the ion concentration recovery step, but in the ion concentration depletion step, the behavior of ions caused by infiltration into the porous structure is greater than the diffusion of ionic species induced by diffusion. . Then, as the force of diffusion increases, the process returns to the ion concentration recovery stage.
  • 10 is a graph showing (a) the lowest concentration change of cations according to the absorption parameter and (b) the lowest concentration change of cations according to the stolen equilibrium concentration according to an embodiment of the present invention.
  • the absorption parameter is a value that can be adjusted according to the absorption amount of the hydrogel.
  • the absorption parameter is defined as ( ⁇ d cap ) / (4D ⁇ ), where ⁇ is the surface tension, d cap is the diameter of the capillary, and ⁇ is the dynamic viscosity of the fluid. Increasing ⁇ and d cap or decreasing ⁇ increases the rate of absorption of the fluid.
  • the Washburn equation is used to describe absorption through a single capillary, but recent studies have shown that the washburn equation can also be used for absorbent mesh structures.
  • non-dimensional Donnan equilibrium concentration Is related to the amount of internal charge in the film.
  • the greater the internal charge of the membrane the higher the ionic flux passing through the membrane, and thus the longer the ion concentration depletion stage can be maintained. 10 (b) It can be seen that the ion concentration depletion step is maintained long when the value is fixed to 10.
  • the microchannels are L in length and filled with 1: 1 electrolyte solution.
  • the space between the reservoir and the membrane surface is the space that can be theoretically analyzed. The flow potential generated by absorption through the membrane was ignored, so the effects of surface conduction or electro-osmotic flow were not considered. Therefore, the domain is simply substituted in 1D form.
  • t time
  • c i concentration of the i-th species
  • J i flow rate per mole of ions along the x-axis.
  • D i is the diffusion coefficient of the i th species
  • F is the Faraday constant
  • R is the gas constant
  • T is the absolute temperature
  • ⁇ is the potential
  • u is the flow velocity in the x direction.
  • the part on the right in Eq. (5) means diffusion, electro-migration, and convection, respectively.
  • no voltage is applied, but related items are used because electrical interactions must be considered. This interaction is shown in the Poisson equation as follows.
  • ⁇ f is the electrical permittivity of the electrolyte solution
  • c + and c ⁇ represent the concentrations of cations and anions, respectively.
  • the ion flow portion of the convective term is usually the term obtained by combining the Stokes equation, the continuity equation, and the differential equations (4) to (6).
  • the simple model proposed in the work of Dhopeshwarkar et al. the ion concentration polarization was induced by the external voltage, so the microchannel-nano channel-microchannel analysis was performed.
  • the capillary ion concentration polarization phenomenon only two portions of the microchannel-nanochannel were analyzed. This is necessary. Thus, there is one less domain than in Dhopeshwarkaret al.'S work.
  • the flow rate u in the microchannel, the convective flow through the membrane by absorption has the following relationship with the absorption rate U imb .
  • Equations (17) and (18) are values representing concentrations and potentials in the microchannels, respectively.
  • S is defined as ⁇ d cap / 4 ⁇ . Since u imb is proportional to t ⁇ 0.5 , the ion concentration depletion step gradually disappears in capillary ion concentration polarization.
  • the dimensionless equations (5)-(6) can be solved at the appropriate boundary conditions to obtain the spatiotemporal concentration distribution.
  • Equation (14) Each is a variable in equation (14), the characteristic time ⁇ D Is L 2 / D, and the characteristic speed is set to D / L.
  • Equation (25) shows that in a quasi-steady state, the change in electrochemical potential is ) 0, only the movement by convection into the membrane can be considered.
  • the Donnan equilibrium concentration in nanoporous membranes is depicted in equations (26) and (27), which means that the flow of anions into the membrane does not pass into the membrane by ideal cation selectivity. Equations (21) and (22) and boundary conditions (24) to (27) were calculated numerically.
  • FIG. 11 is a schematic view illustrating a non-powered desalination structure 30 formed by densely forming a plurality of particle-shaped porous structures 20 ′ according to an exemplary embodiment of the present invention.
  • FIG. 11 exemplarily illustrates a non-powered desalination structure 30 formed by dense a plurality of particle-type porous structures 20 ′, which may be referred to as “artificial soils”.
  • the non-powered desalination structure 30 of the present invention is not limited to the form of the present example, and may be changed to various forms within a range capable of collecting fresh water in the desalination structure.
  • the porous structure 20 ′ of FIG. 11 may have a particle shape. That is, a material having a selective permeability to ions such as hydrogel and Nafion and at the same time having a capillary force that sucks a fluid, including a plurality of capillaries, may be made into particles to form a porous structure 20 ′.
  • An ion depletion zone may be formed by a capillary ion concentration polarization phenomenon in a portion where the desalination target fluid B such as brine and the respective particles are adjacent to each other.
  • Ion depletion region may be formed having a size of about 1 ⁇ 10,000 ⁇ m. Therefore, fresh water may be collected between the inside of each particle (nano / micro pores) and the ion depletion region boundary P.
  • ion depletion regions may be formed to overlap each other in the inside of the dense mass 30 (ie, the space between the particles and the particles). And, the outside of the dense mass 30 may be in contact with the desalination target fluid (B).
  • the lump 30 (the non-power desalination structure 30) in which the plurality of particles are concentrated forms a macro structure, and when immersed in the desalination target fluid B, fresh water may be collected therein. Therefore, since the desalination water of the 90% or more can be collected inside the dense mass of particles until the ion concentration depletion step, the collected water can be utilized in various ways. For example, if the plant roots can be plugged into normal growth, it can be used as artificial soil. Then, after the contact with the desalination target fluid (B) is blocked before changing to the ion concentration recovery step, the porous structure 20 'is dried, and then contacted with the desalination target fluid (B) again, it is repeatedly used for desalination. Can be.
  • the present invention proposes a novel ion concentration polarization phenomenon based on a capillary tube.
  • Capillary forces embedded in the nanoporous network instead of an external electric field cause ion selective flow and form ion depletion regions around the porous structure. Since the state-of-the-art desalination mechanism filters by particle size, a lot of electrical energy is required, and when the development of a small sized desalination / purification system is required, the mechanism of capillary ion concentration polarization is driven without an external power source.
  • This spontaneous desalting mechanism can be used in disaster or underdeveloped areas. In order to implement such a system, a weak flow around the nanoporous membrane must be maintained, the charge inside the membrane must be increased to increase ion selectivity, and the absorption must be maintained for a long time.

Landscapes

  • Health & Medical Sciences (AREA)
  • Clinical Laboratory Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)

Abstract

La présente invention concerne un procédé de dessalement sans électricité exploitant le phénomène de polarisation de concentration d'ions en capillaire et une structure de dessalement non électrique. Un procédé de dessalement sans électricité selon un mode de réalisation de la présente invention comprend les étapes suivante : (a) la mise en contact d'une structure poreuse (20) présentant une perméabilité sélective vis-à-vis d'ions avec un fluide cible de dessalement (12) ; et (b) l'initiation d'une polarisation de concentration d'ions en capillaire (CICP) par imbibition d'ions présentant une perméabilité sélective du fluide cible de dessalement (12) dans la structure poreuse (20), la force pour imbiber les ions présentant une perméabilité sélective dans la structure poreuse (20) étant due à une force capillaire d'un capillaire contenu dans la structure poreuse (20).
PCT/KR2017/002498 2016-03-10 2017-03-08 Procédé de dessalement sans électricité exploitant le phénomène de polarisation de concentration d'ions en capillaire et structure de dessalement non électrique Ceased WO2017155298A2 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR10-2016-0029071 2016-03-10
KR20160029071 2016-03-10
KR1020170027605A KR101903596B1 (ko) 2016-03-10 2017-03-03 모세관 이온 농도 분극 현상을 이용한 무전원 담수화 방법 및 무전원 담수화 구조물
KR10-2017-0027605 2017-03-03

Publications (2)

Publication Number Publication Date
WO2017155298A2 true WO2017155298A2 (fr) 2017-09-14
WO2017155298A3 WO2017155298A3 (fr) 2017-11-02

Family

ID=59789669

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2017/002498 Ceased WO2017155298A2 (fr) 2016-03-10 2017-03-08 Procédé de dessalement sans électricité exploitant le phénomène de polarisation de concentration d'ions en capillaire et structure de dessalement non électrique

Country Status (1)

Country Link
WO (1) WO2017155298A2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10669572B2 (en) 2017-05-31 2020-06-02 University Of Notre Dame Du Lac Ultra-sensitive multi-target lateral flow molecular assay with field-induced precipitation

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20000063266A (ko) * 2000-06-12 2000-11-06 박연수 오,폐수의 불순물 무동력 여과처리장치
JP2004283798A (ja) * 2003-03-25 2004-10-14 Masato Kino 膜を用いた液分離装置
KR101387136B1 (ko) * 2012-03-09 2014-04-21 고려대학교 산학협력단 담수화 방법 및 담수화 장치
JP6073072B2 (ja) * 2012-04-27 2017-02-01 株式会社キコーコーポレーション ナノファイバー不織布を用いたろ過装置
KR20150094955A (ko) * 2014-02-12 2015-08-20 서울대학교산학협력단 무전원 담수화 기능을 가지는 구조물 및 무전원 담수화 방법

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10669572B2 (en) 2017-05-31 2020-06-02 University Of Notre Dame Du Lac Ultra-sensitive multi-target lateral flow molecular assay with field-induced precipitation

Also Published As

Publication number Publication date
WO2017155298A3 (fr) 2017-11-02

Similar Documents

Publication Publication Date Title
Li et al. Solution‐pH‐modulated rectification of ionic current in highly ordered nanochannel arrays patterned with chemical functional groups at designed positions
He et al. Tuning transport properties of nanofluidic devices with local charge inversion
Kishi et al. Reversible volume change of microparticles in an electric field
ES2037273T3 (es) Proceso de focalizacion isoelectrica y medios para llevar a cabo dicho proceso.
Park et al. Capillarity ion concentration polarization as spontaneous desalting mechanism
Oh et al. Capillarity ion concentration polarization for spontaneous biomolecular preconcentration mechanism
BRPI0418670B1 (pt) método de separação de partículas sólidas de uma suspensão comprendendo um líquido e método decontrole da consolidação de um leito de partículas sólidas dentro de um líquido.
Jung et al. Fabrication of temperature-and pH-sensitive liquid-crystal droplets with PNIPAM-b-LCP and SDS coatings by microfluidics
Rubin et al. Induced-charge capacitive deionization: the electrokinetic response of a porous particle to an external electric field
JP2013520298A (ja) 動電学的流体システム
WO2017155298A2 (fr) Procédé de dessalement sans électricité exploitant le phénomène de polarisation de concentration d'ions en capillaire et structure de dessalement non électrique
Li et al. Electric field-controlled ion transport in TiO2 nanochannel
Nagasawa et al. Electrophoresis of polyelectrolyte in salt solutions
CN110038443A (zh) 一种缓解碳纤维纸-聚醚砜复合导电分离膜污染的方法
CN103275174B (zh) 一种通用型聚丙烯酰胺凝胶蛋白质快速分离和染色试剂盒
Lee et al. Microfluidic devices with permeable polymer barriers for capture and transport of biomolecules and cells
Matovic et al. Field effect transistor based on ions as charge carriers
US12201942B2 (en) Boron-nitride nanotube membranes
Li et al. Polyvinylsilazane layer coating and its application in poly (dimethylsiloxane) microchip electrophoresis
Wang et al. Bulk modification of polymeric microfluidic devices
KR20170106202A (ko) 모세관 이온 농도 분극 현상을 이용한 무전원 담수화 방법 및 무전원 담수화 구조물
Yang et al. Gated ion transport through layered graphene oxide membranes
Chaudry Water and ions transport mechanism in hyperfiltration with symmetric cellulose acetate membranes
Guelch et al. Electrochemical stimulation and control of electroactive polymer gels
WO2015122613A1 (fr) Structure à fonction de dessalement non motorisée et procédé de dessalement non motorisé

Legal Events

Date Code Title Description
NENP Non-entry into the national phase in:

Ref country code: DE

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17763559

Country of ref document: EP

Kind code of ref document: A2

122 Ep: pct application non-entry in european phase

Ref document number: 17763559

Country of ref document: EP

Kind code of ref document: A2