JP6422032B2 - Flow separation type pore diffusion membrane separation module for concentration - Google Patents

Description

  The present invention relates to a pore diffusion type flat membrane separation module that performs solid-liquid separation using a pore diffusion mechanism of a flat membrane, and more particularly to a membrane module that is suitable for application in the concentration field by a membrane separation module to which a flow separation mechanism is added. The present invention relates to a module that uses a force (axial concentration force) acting so as to move away from a wall surface acting on particles dispersed in a liquid to be treated. Due to the velocity gradient caused by the laminar flow of the liquid, a force generated in a direction perpendicular to the flow acts on the particles. As a result, the particles in the liquid move away from the wall.

    Membrane separation modules that separate and purify substances dissolved or dispersed in a liquid include hollow fiber membrane modules, tubular membrane modules, and flat membrane membrane modules according to the shape of the membrane to be used. In either case, the pressure difference between the membranes is 1 atm or more, and the driving force for transporting the substance is a module for filtration separation mainly using the transmembrane pressure difference. Therefore, the function of the membrane separation module is to remove specific particles (for example, bacteria and viruses) dispersed in the liquid or high molecular weight substances (for example, protein complexes) to be dissolved. Furthermore, in these modules, a structure that can withstand the applied pressure must be further taken against liquid leakage. In the case of a flat membrane, in order to hold the membrane, a part of the flat membrane and the flat membrane support are bonded and fixed with resin etc. Especially when the effective membrane area exceeds 0.1 square meters, the transmembrane pressure difference Supports and containers (housings) that can withstand heat are made of stainless steel or metal and lose the degree of freedom in the form of modules. Alternatively, as in the case of a hollow fiber membrane, a cylindrical module in which a part of the membrane and the container are bonded with a resin or the like is obtained.

  In the membrane filtration method, the transmembrane pressure differential is unavoidable, and this differential pressure usually exceeds 1 atm. In the case of a flat membrane module, this differential pressure is supported by the outermost frame of the module. Therefore, a reinforcing material is added to the outermost frame. The tension applied to the reinforcing material is at least (transmembrane pressure difference / flat membrane area), and the material must withstand several times the force in design.

 In the membrane filtration method, the volumetric flow of liquid is used with the transmembrane pressure as the driving force. It dissolves or disperses in the liquid, and the components are trapped inside the membrane by the sieving effect through the pores of the membrane. Since the object to be removed is clogged in the pores in the membrane, the membrane regeneration process is difficult, and therefore a module that assumes membrane filtration is generally single-use (disposable). Of course, it is also difficult to recover the components concentrated in the membrane.

Since the particle removal rate in the membrane filtration method depends on the relationship between the pore size of the membrane and the particle size of the particles to be removed, the average pore size of the applied membrane decreases as the size of the particles to be removed decreases. I have to do it. That is, in filtration, the average pore size of the membrane of the membrane module is selected corresponding to the particles to be removed. The performance of particle removal can be significantly enhanced by designing the pore structure of the membrane. Increasing this possibility makes it impossible to recover the concentrated particles trapped in the membrane. That is, in the membrane filtration method, increasing the particle removal performance and increasing the concentration recovery rate of the particles have a trade-off relationship.

As the filtration module, an assembly type in which a membrane can be loaded and removed is desirable, but the pressure resistance is required, and the module is complicated and mechanically robust. The membrane pore size of the membrane is generally a module in which a membrane filtration method utilizing the sieving effect of the membrane is assumed, and a module having a fixed average pore size of the membrane. Development research on the concentration of molecules and particles using membrane modules has been studied on the premise of filtration methods. However, none of the measures against membrane furing as an inevitable phenomenon of membrane filtration methods is a method that does not meet the purpose of concentration.

There are filtration methods called parallel filtration, tangential flow filtration, and cross flow filtration as a method for partially eliminating membrane furling, which is a problem in membrane filtration. In this filtration method, the gel layer (or a high concentration polarization layer of a high molecular weight substance) deposited on the membrane surface is a method of suppressing polarization by removing the layer or stirring effect by the force of flow. Even in these methods, since the transmembrane pressure is loaded with a pressure (usually 1 atm or more) necessary to give the filtration speed of the volume flow as filtration, clogging of pores in the membrane always occurs. Since the liquid to be filtered flows in the module, the parallel filtration module is required to have higher pressure resistance than a normal dead-end module. Since the clogging component of the pores in the membrane is a component to be concentrated, even in this case, the concentration by the membrane has not been put into practical use due to the low recovery rate and the high recovery cost.

As a membrane concentration method that has been put to practical use, there is a method of using a reverse osmosis membrane to concentrate only by removing moisture at a transmembrane pressure difference of several tens of atmospheres. So-called non-porous membranes are used so that no physical pores can be observed in the membrane, and the concentration of the concentration target component is such that only the membrane surface is trapped or concentration-polarized. In this method, it is impossible to concentrate only specific components.

The flat film referred to in the present invention has a film thickness of 0.2 μm or more and less than 100 μm, and the ratio of the area of the film plane to the square of the film thickness is 10,000 or more. That is, the shape of the flat film used in the module of the present invention is approximated by a two-dimensional flat shape such as paper. In this module, since the pore diffusion is applied, the transmembrane pressure difference applied is low.
For example, the transmembrane pressure is 0.05 atm or less. Therefore, the film thickness is thinner than the film used for the filtration module. The film thickness of the flat film means not the physical apparent thickness of the flat film but the thickness of the part that controls the permeability of the substance observed with an optical microscope or an electron microscope. The pore diffusion module referred to in the present invention is a membrane separation using a pore diffusion mechanism that occurs under laminar flow where the transmembrane differential pressure is 0.05 atm or less and the strain rate of the flow of liquid to be treated on the membrane surface is 2 / sec or more. Means module.

  Membrane separation that allows separation and concentration of specific substances as well as removal of particles under mild conditions is highly expected to be put to practical use particularly in the biotechnology field. Physiological activity can be maintained because of separation without applying heat. Concentration without applying heat is becoming indispensable in the manufacturing process of biopharmaceuticals and in the manufacturing process of cosmetics and foods. In addition, there is high expectation as a technology that replaces centrifugation as a concentration technology that does not apply heat. In these fields, removal by membrane filtration is now indispensable as a technique for removing infectious fine particles. Similar to membrane filtration, pore diffusion membrane separation technology has been put into practical use not only as a removal method but also as a separation or concentration technology for component molecules.

What is membrane separation technology in the present invention?
(1) The pressure difference (transmembrane pressure difference) between the front and back surfaces of the membrane is used as the driving force for transporting the substance (flowing as a fluid), and a hydrodynamic flow (volume flow) is generated. Membrane filtration technology to remove particles by sieving effect in relation to
(2) The concentration difference between the two liquids through the membrane is used as the driving force for mass transfer, and the difference in the thermal motility (so-called Brownian motion) of the molecules that make up the material without the fluid volume flow. Caused by separation using the difference in the diffusion rate in the pores using the sieving effect, the sieving effect caused by the relationship between the pore size and the particle size of the pores in the membrane, and the laminar flow of the liquid to be treated on the membrane surface Pore separation technology (steady method pore diffusion technology) that separates by utilizing the flow separation effect that occurs in this way, or the stationary method inside the membrane while only the medium that makes up the fluid flows in a volumetric flow with a slight transmembrane pressure difference “Hole diffusion” technology using pore diffusion technology (hereinafter simply referred to as “hole diffusion technology without distinguishing between steady-state pore diffusion technology and“ hole diffusion ”technology)”;
(3) Free volume space created by the difference in affinity between the membrane and the substance and the thermal motility (micro-Brownian motion) of the material polymer constituting the membrane, using the concentration difference across the semipermeable membrane as the driving force for mass transfer Diffusion dialysis technology (conventional dialysis and reverse osmosis) that separates molecules by the difference between the size of the substance and the size of the molecule of the substance,
Means.

Patent Publication 2006-0555780 Patent Publication 2014-24064 K. Kamide, S. Manabe, Polymer J., 13 (No. 5), pp459-479 (1981)

  The present invention provides a membrane concentration module that realizes a membrane concentration method that does not require thermal energy. Without using a membrane filtration method in which the load of the transmembrane pressure is indispensable, (1) diffusion in the pores (Patent Document 1), (2) a sieving mechanism by the pores in the membrane, and (3) the liquid to be treated A flow separation mechanism (defined in Non-Patent Document 1) caused by the strain rate of the film surface is used. That is, an object is to provide a flow separation type concentrating hole diffusion membrane separation module that realizes pore diffusion. By using the module, it is possible to concentrate and collect not only the particle components but also the dissolved molecules while preventing clogging of the pores of the membrane. Furthermore, the membrane module can be regenerated.

  In the present invention, it is most important to design the flow path in the module that efficiently laminates the liquid to be treated on the flat membrane surface. The design is such that the transmembrane pressure difference is maintained at 0.05 atm or less at all locations on the flat membrane, and the strain rate of the liquid to be treated on the membrane plane is set to a predetermined value or more. In particular, in membrane concentration, the liquid to be treated flows repeatedly on the membrane surface, so that the membrane surface must be stable over time. There is also a need for a flow path design that prevents irreversible clogging of the pores in the membrane or on the membrane surface or furling of the membrane surface.

      The first feature of the present invention is that it is required to be used under the condition that the transmembrane pressure difference in this module is stably operated at 0.05 atm or less. In order to satisfy this condition, the cross-sectional area of the flow path as a module must be greater than a certain value, and the length of the flow path must be less than or equal to the value determined by the cross-sectional area, the viscosity of the liquid to be treated, and the flow rate. This is based on the premise that the mechanism for preventing the fluctuation of the transmembrane pressure difference limits the overall shape of the module. This pressure stability condition was set based on the experimental fact that the fluctuation of the transmembrane pressure difference accelerated the clogging of the membrane. Here, the stable pressure means that the transmembrane pressure does not exceed 0.1 atm even if pulsating. This condition is the homogeneity of the flow path of the module, the position of the outlet of the flow path on the primary side, the location where the flow path is open to the atmosphere, and the operating conditions ( Limiting the transmembrane pressure and flow rate). The homogeneity of the flow path is required so that there is no portion where the transmembrane pressure difference temporarily becomes 0.2 atmospheres or more, or there is no portion where the pressure is 0.2 atmospheres or more even locally. Clogging progresses from non-uniform locations.

The second feature of the present invention is that the flow path on the primary side in the module is designed so that the liquid to be processed flowing along the membrane surface becomes a laminar flow. The liquid that permeates and flows out of the membrane is defined as a secondary side liquid, and the flow path of the liquid is referred to as a secondary side flow path. The walls forming the primary channel are all smooth solid surfaces, and there are no depressions or corners that can cause turbulence in the primary channel. In a flow that is a laminar flow, the flow of the liquid on the surface of the flat membrane that forms part of the flow path through which the liquid to be processed flows is important. The discovery that the flow separation effect appears if this flow is a laminar flow gave rise to a flow separation type module of the present invention. The appearance of laminar flow will be described later (a) and (b)
This is possible if the liquid flow in the primary flow path of the region is set to a Reynolds number of 2000 or less. In order to realize a function unit of 2000 or less, the flow thickness may be reduced. A laminar flow is realized in the subdivided flow path only by subdividing the width of the flow paths in the (a) and (b) regions in the primary flow path along the flow path .

The third feature of the module according to the present invention is a hole diffusion module, in which (a) a laminar flow in which a channel having a length of 3 cm or more is connected to the primary channel of the liquid to be treated without substantially disturbing the laminar flow. (B) A channel having a length of 6 cm or more, and among the four walls forming the channel, two parallel surfaces are smooth solid plates, and the remaining two surfaces are flat membranes. A space part constituted by a membrane surface, and a diffusion part in a hole accompanied by flow separation in the space part, and (c) a plurality of parts constituted by a back plane of the flat membrane and partitioning the space part. And (d) a fluid accumulation region in which a plurality of the flow paths are integrated, and at least four types of regions.

Details of the four regions are as follows.
(A) Laminarization region of the liquid; in the region of (a), the region is provided so that the primary side liquid can be transferred by a smooth long spring, and is connected to the inlet of the primary side liquid into the module. The length of the flow path in this region must be 3 cm or more. The longer it is, the better, but it is not necessary to be 45 cm or more. The cross-sectional shape of the primary-side liquid channel (abbreviated as primary-side channel) in this region is preferably the same as that in region (A). (A) A solid (plastics plate) having a smooth surface other than the flat membrane used in the region (b ) is desirable as a material of the wall forming the primary flow path. The case where the laminar flow region of the primary fluid into the module which is part of (a) and the region of (a) are integrated, and the case where the primary side liquid into the module which is part of (a) is integrated. If the entrance portion is designed to be detachable, it becomes easy to give only the sanitary property only to the region (a).

(A) In-hole diffusion region with flow separation through a membrane; (A) A region connected to a plurality of trickles without disturbing the flow of the liquid coming out of the region. The cross section of the flow path is barrel-shaped in units of trickle flow paths. Of the four walls forming the shape of the barrel, the two parallel surfaces are smooth solid plate-like bodies and the other two arc-shaped surfaces. Of these, at least one surface is constituted by the film surface of the flat film. The flat membrane is a region where a convex surface is formed and through-hole diffusion accompanied by flow separation occurs through the membrane. In this region, the function of separating, concentrating, removing, and isolating substances is exhibited, so the fluid must be laminar in the flow path. The strain rate at the flat membrane surface of the fluid flow in the region should be 2 / sec or more. Desirably, it is 20 / second or more and 200 / second or less.

  The flat membrane forming the region (a) has an average pore diameter of the membrane surface smaller than that of the back surface, the membrane surface smoothness of the membrane is 10 μm or less, and the physical apparent thickness is 100 μm or less. The average pore diameter in the velocity method is 10 μm or less, 10 nm or more, the porosity is 60% or more, the bubble point in water is 0.1 atmosphere or more, and the flat membrane is a nonwoven fabric made of a hydrophilic material or A polymer porous membrane is desirable. In particular, in the concentration module, it is more desirable that the thickness of the layer showing the ability to capture particles on the membrane surface is 100 nm or more and 20 μm or less.

  (B) The cross-sectional shape of the basic unit constituting the flow path is two parallel walls with a height of 2 mm or more and less than 10 mm, and two flat plates that form a pair of arcs with a width of 2 mm or more and less than 40 mm. It is desirable to have a barrel shape expressed by a convex wall made of a film. By making the cross-sectional shape similar to the shape and size of the channel in the laminar flow channel region of (a), a smooth flow can be ensured at the connecting portion between (a) and (b). Due to the presence of the two parallel walls, it is easy to ensure a smooth flow at the connecting portion. The length of the flow path of (a) is not less than 700 mm and not less than 700 mm. When the length of the flow path exceeds 700 mm, it is difficult to stably maintain the transmembrane pressure difference at 0.05 atmospheric pressure or less.

    (C) A space area constituted by the back surface of the flat membrane; (c) a parallel wall part of (a) and a wall part that exists symmetrically with the flat film as a mirror surface are provided in the space part of the storage area of (c) Thus, the cross-sectional shape of the flow path (A) can be maintained. The transmembrane pressure difference can be stably maintained by the presence of the same wall portion through the flat wall and the parallel wall portion constituting the flow path shown in (a). The wall in this region serves as a flow path for the diffusion liquid and a support for the flat membrane. The space region also serves as a reservoir for the diffusion liquid. A wall for guiding the diffusion liquid may be provided in the space. By providing the guiding wall with the role of a flat membrane support, it is possible to prevent the membrane from vibrating even when the strain rate on the membrane surface is 100 / sec or more. Caused by deformation and transmembrane pressure due to swelling of the flat membrane when immersed in water due to the presence of parallel walls in a mirror-symmetrical relationship through the flat membrane in the areas (a) and (c) The appearance of irregularities on the film surface due to the mechanical deformation of the flat film can be prevented.

      Due to the existence of the laminar flow channel area (a), the fluid flows on the surface of the flat membrane while drawing smooth streamlines on the surface of the flat membrane. By drawing complex figures of streamlines on the membrane surface, clogging of the pores of the membrane progresses, and the discovery of the fact that solute intrudes into the membrane using the transmembrane pressure as a driving force (A) of the present invention. ) Led to the need for an area. When the length of the flow path in the area (a) is 3 cm or more, the flow separation by the laminar flow on the film surface in the area (a), that is, the larger the molecular weight (or particle diameter), the larger the membrane surface. The phenomenon of flowing away (this is called the flow separation effect) becomes remarkable. In order to stably maintain the laminar flow realized in (a) in the (b) region, the wall surface forming the flow path of (b) needs to be smooth. Further, it is desirable that the cross-sectional area of the flow path is uniform within the flow path in the region (a). One surface of the wall surface forming the flow path or two parallel surfaces are constituted by the film surface of the flat film. The existence of the laminar flow maintaining zone in (c) is indispensable when the modules are connected in series, and even when not connected, it is necessary for connecting with the inlet / outlet of the module with smooth streamlines. In the space formed by the back surface of the membrane in (d), the flat membrane is placed at an angle at which a plate-like body similar to the plate-like body constituting the channel in (a) intersects the direction of the channel. Dynamically supports and forms a flow path for the diffusion liquid. The cross-sectional area of the flow path of the diffusion liquid is more than twice the cross-sectional area of the flow path of (A), and does not play a role in controlling the flow of the diffusion liquid.

  The fourth feature of the present invention is that the three regions (a), (b) and (c) are connected by a common common plane, and the liquid flow in the flow path and the flat membrane surface are substantially parallel. In that point. That is, the regions (a) and (a) are connected in series at substantially the same height, and the region (c) is arranged in parallel in parallel through the flat membrane of the region (a). By this connection, the laminar flow in the (a) region can be stably maintained.

The fifth feature of the present invention is that (a) the flat membrane forming the flow path in the region is made of a hydrophilic material.
In the case of the module for concentration, it is desirable that the module is made of cellulose having particularly high hydrophilicity. The flat membrane constituting the module of the present invention has the most important role in governing the transport properties of materials. Therefore, it is desirable that the characteristics as a flat film have the following characteristics.
That is, (1) The average pore diameter calculated by the filtration rate method is 10 nm or more and less than 10 μm.
The processing speed as a module is not determined only by the pore characteristics of the flat membrane, but mainly by the transmembrane pressure difference and the strain rate on the membrane surface. Therefore, the demand for the average pore size is determined by the substance to be concentrated by processing. For example, the average pore size is 60 nm for virus concentration, 700 nm for bacterial concentration, and 25 nm for prion concentration.
(2) The porosity is 60% or more.
Since the mass transport rate by pore diffusion is proportional to the porosity, the larger the porosity, the better. Unlike membrane filtration, the mechanical stress (transmembrane differential pressure) applied to the membrane is small, so there is little need to set an upper limit for the porosity.
(3) The smoothness of the flat film surface is 10 μm or less.
The smoothness is the size of the basic structure constituting the flat membrane (fibers in the case of non-woven fabrics, average pore diameter of the surface in the case of porous membranes or secondary particles in the case of membrane formation by the microphase separation method). It is defined as 3 times. This smoothness is a measure for setting the thickness of the laminar flow on the film surface.
(4) The physical apparent film thickness of the flat film is 100 μm or less.
In the case where the flat film is formed of two or more kinds of structures, the apparent film thickness contributes to the thickness even in a portion that is not dominant in mass transport. Including this part, it is defined as the physical apparent film thickness of the flat film. In pore diffusion, since the concentration gradient becomes an important driving force in mass transport, the apparent film thickness is preferably as thin as possible. In particular, it is desirable that the module intended for concentration is thinner than that for removal.

  The flow paths in the areas (a) and (b) are formed by a plurality of trickles. The cross-sectional shape of one trickle channel (unit channel) is preferably a rectangular parallelepiped or barrel. By setting the height to 2 mm or more and less than 10 mm, the strain rate of the flow on the flat membrane surface accompanying the liquid flow can be easily achieved to 2 / second or more. It has been experimentally clarified that increasing the strain rate increases the flow separation effect. When the strain rate is increased, the transmembrane pressure difference increases, and the pressure gradient in the flow path also increases. These factors that increase the transmembrane pressure are significant when the cross-sectional area of the flow path is reduced. The width of the flow path is 2 mm or more and less than 40 mm. If the width is too large, a flow shortcut is likely to occur, and the flow separation effect is difficult to appear. The length of the flow path is preferably not less than the width and less than 700 mm. It is necessary to shorten the channel length in order to maintain the transmembrane pressure difference below 0.05 atm on all sides of the flat membrane.

  In the present invention, the transmembrane pressure difference is maintained at 0.05 atm or less at all points of the flat membrane, which is indispensable to make the contribution of membrane filtration zero. The transmembrane pressure difference is the most important operating condition for realizing that only molecules (usually water) constituting the liquid medium pass through the pores of the membrane in a volume flow. When membrane filtration occurs, the pores of the membrane are clogged, and it is generally not desirable as a module for concentration that requires long-term operation. For this reason, laminar flow in the flow path in the region (a) is realized, and a transmembrane pressure difference is applied after a predetermined strain rate is achieved. On the contrary, the operation of giving the strain rate after applying the transmembrane pressure must be avoided because the membrane is clogged. By discovering this clogging phenomenon, the necessity of the area (a) was found.

        The module of the present invention enables pore diffusion membrane separation to be easily performed with good reproducibility. The effect of separation, concentration, removal and sequestration, which is a feature of pore diffusion membrane separation, can be demonstrated in a continuous and scalable manner from the laboratory scale to the practical scale. In the module of the present invention, a series of solutions having different component compositions can be continuously recovered from the side of the diffusion solution after separation of the pore diffusion membrane, and a solution in which a specific component is concentrated at a predetermined magnification can be simultaneously recovered. This module can be operated stably over a long period of time, and is optimal for a concentration module. In the module, a pressure-resistant member is not added by taking advantage of the low load pressure. Therefore, pressure resistance is not required as a member necessary for module production, and the module weight per effective membrane area can be easily reduced to 1/2 or less that of a conventional membrane module for membrane filtration. As a completeness test, the pressure hold method can be adopted, and the load pressure at that time is 0.1 atm.

        The power required to operate the module of the present invention is a 0.05 atm pressure source and a flow rate source for laminar flow, both of which consume less energy than membrane filtration. Furthermore, since there is little possibility of liquid leakage from the module, a free flow path design is possible. Since it is easy to connect a plurality of modules of the present invention in series or in parallel, it is easy to build a system having a large membrane area necessary for practical use.

        FIG. 1 shows an example of the module of the present invention. FIG. 1a at the top shows a schematic diagram of five sheets (sheets 1, 2, 3, 4, and 5 in FIG. 1) constituting the module of the present invention. The most important part (sheet 3) is shown in the center of FIG. 1a. It is composed of a plurality of (9 in FIG. 1) channels (4.5) in length in the laminar flow channel region (a) and 4.5 cm in length (a) directly connected to the channel (a). The in-hole diffusion region accompanied by the flow separation and the fluid accumulation region (d) (in FIG. 1, a plurality of flow paths are connected to and integrated with the external system at the outlet of the module) are connected in the same plane. The walls of the regions (a), (b), (c), and (d) are made of polycarbonate except for the flat membrane 1.

In the region shown in FIG. 1 (a), the fluid flows in a laminar flow, flow separation occurs in the flow, and diffusion in the pores occurs in the flat membrane. A cross-sectional view of the flow path in region (A) is given in FIG. As shown in this cross-sectional view, when the fluid is flowing in the cross-sectional shape, the flow path has a barrel shape due to the deformation of the film due to the transmembrane pressure difference.
The channel height is 4 mm and the channel width is 5 mm. The two parallel plate-like bodies forming the flow path are made of polycarbonate and have a thickness of 0.5 mm. The length of the channel is 18 cm. In the area (A) on the inlet side of the flow path, there are nine flow paths connected to the flow path in the area (A), and the cross-sectional shape is a rectangle of 4 mm × 5 mm. The inlet of this channel is connected to a urethane tube (made by CHIYODA) 5 having an inner diameter of 4.5 mm and an outer diameter of 6.0 mm. The connecting portion is made of a silicon-based adhesive, and the polycarbonate wall of the flow path in the region (A) and the tube 5 are in close contact with each other.

The sheet indicated by 1 in FIG. 1 is a porous flat membrane. This is a regenerated cellulose membrane having an average pore diameter of 80 nm and a thickness of 100 μm formed by a microphase separation method. The hole diameter ratio between the front and back surfaces (measured with an electron microscope) is 1/3. The average pore diameter of the two sheets (flat membranes) 1 in the figure is the same. The flat membrane is set so that the surface of the flat membrane comes to the side of the sheet 3 that is in contact with the two front and back surfaces. That is, the flat membrane surface is in contact with the liquid flowing in the flow path (A). The flat membrane 1 and the sheet 3 are brought into close contact with an adhesive or in contact with grease or the like. When the material of the sheet 3 is polycarbonate and the material of the flat membrane 1 is regenerated cellulose as the adhesive, a urethane adhesive is used.
For the adhesion between the flat membrane 1 and the sheet 3, a physical adhesion method such as packing may be employed. The central sheet 3 has an inlet 5 for the liquid to be processed and is directly connected to the connection port to the region (d). The liquid that has passed through the inlet 5 becomes a laminar flow in the region (a) (the cross-sectional shape of the channel is shown in the section cc in FIG. 1c), passes through the channel in the region (a), After passing through (d), exit the exit 6 and lead out of the module. Sheets 2 and 4 are manufactured by laminating two thin polycarbonate plates having a thickness of 0.5 mm at regular intervals of 3 to 5 mm. A storage area of the region (c) is formed by the stacked stepped body (so-called polydan plate-like body). That is, when two thin plate-like bodies are laminated, they are molded and fused with a strip-like object constituting a wall surface arranged in parallel to support both plate-like bodies. This parallel wall surface exists symmetrically with the parallel wall surface of the region (a) and the flat membrane 1 as a mirror surface. The symmetrical wall forms the space between the sheets 2 and 3, giving the section aa and the section bb in FIG. Since the sheets 2 and 4 are two-tiered laminates having a rectangular space, rectangular spaces are prepared as shown in the sectional view of FIG. 1c.

      As the flat membrane 1 in FIG. 1, a cellulose acetate porous membrane or a regenerated cellulose porous membrane produced by a microphase separation method or a nonwoven fabric laminated with long fibers is used. When the average pore diameter of the flat membrane is 0.5 μm, a collected liquid from which bacteria have been removed (corresponding to the membrane permeate) is obtained, and the bacteria are concentrated in the primary liquid. In a regenerated cellulose porous membrane having an average pore size of 80 nm, viruses are also concentrated in the primary side liquid. FIG. 1b shows an elevation view of the module. FIG. 1c shows cross-sectional views along the aa, bb, and cc planes.

Preparing a module hole diffusion method shown in FIG. The parts required for the assembly of the module are two flat membranes 1 (both of them can be combined with membranes having different average pore sizes from those having the same average pore size, but in this embodiment, the same membrane is used. shown), FIG. 1 and similar sheet 2 primary flow path is provided, sheet 2 to provide a flow path for the secondary liquid membrane permeate formed in the support body for suppressing deformation of the flat membrane 1 , And one sheet 4 each. Sheets 2, 3 and 4
All of these are manufactured by cutting a commercially available plastic cardboard sheet (corrugated cardboard sheet manufactured by melt molding of plastics). A urethane tube 5 is attached to the sheet 3. The flat membrane sheet 1 was produced by a microphase separation method (Kenji Kende et al., Polymer Journal, 34, 205 (1977)). The film thickness of the porous acetate membrane produced by this method was 80 μm, the average pore size by the water filtration method was 80 nm, and the porosity was 80%. From observation with an electron microscope, the ratio of the hole diameters on the front and back surfaces was 1: 3. The basic unit channels (thickness 4) subdivided into nine (9 ) channels (regions) in the sheet 3 by cutting from a commercially available Pradan sheet as a base material before the cutting of the sheets 2, 3 and 4 mm, width 4 mm, length 100 mm), and the flow path in the region (a) was left without cutting. The number of the flow paths is nine. The plate-like body of the wall forming the flow path has a role of supporting the flat membrane sheet 1. The plate-like body and the flat membrane sheet 1 are bonded and fixed with a urethane-based adhesive. The thickness of the plate was 0.5 mm. The two membrane surfaces of the flat membrane 1 and the end portion of the plate-like body that is the wall portion of the sheet 3 were bonded with a two-component urethane resin. In the region (a) of the sheet 3, nine urethane tubes (made by CHITODA) having an inner diameter of 4.5 mm and an outer diameter of 6.0 mm shown in FIG. The plate-like body forming the walls of the sheets 2 and 4 shows the deformation of the flat membrane 1 that occurs when the liquid flows in the flow path in the sectional view taken along the line BB in FIG. 1c . Flat membrane 1 is deformed in a convex shape, the wall portion plane is a barrel-shaped cross section shape closer to the rectangular shape showing a straight line.

      The sheets 2 and 4 are bonded to the upper and lower sides of the sheet 3 to which two flat films are bonded. At this time, the adhesive portion is a portion other than the flat membrane 1 forming the flow path of the region (A), and is embedded so that the liquid flowing through the flow path does not flow out of the module. The module of the present invention is completed by embedding pipes or tubes for connection with an external system at the inlet 5 and the outlet 6 of the flow path. Since the entrances 7 and 8 of the sheets 2 and 4 serve as the exit for the diffusion liquid, the number of entrances is appropriately selected according to the purpose. In some cases, the diffusion liquid outlet is provided with a flow rate adjusting cock to control the flow rate of the diffusion liquid. In this case, the average pore diameter of the flat membrane is 100 nm or more and the film thickness is 100 μm or less, or the transmembrane pressure difference exceeds 0.03 atm.

The outlet 6 of the seat 3 is opened to atmospheric pressure so that the maximum transmembrane pressure for the module is 0.03 atm, and the water head pressure difference at the inlet 5 is less than 30 cm head of water column. A liquid circuit was prepared, and pore diffusion accompanied by flow fractionation of an aqueous solution containing 2000 ppm of ferric hydroxide kloid having an average pore diameter of 30 nm was performed using this circuit. The average velocity U of the liquid to be treated inside the flow path was 5.7 cm / s and the flow thickness was 0.3 cm. Therefore, the strain rate on the film surface was 76 sec ⁻¹ .

When the transmembrane pressure was 0.005 atm, the membrane filtration rate was 1.0 liter / m ² / hr, the particle concentration in the recovered liquid was 20 ppm or less, and the particle concentration in the primary liquid was 3850 ppm. The membrane permeability of the particles was 0.01 or less. Therefore, the logarithmic divisor of the particles in this module was 2 or more. The concentration rate of the particles was 1.92 times. The solution volume on the primary side was initially 2.5 liters but was about 1.3 liters after 48 hours.

      The present invention can be used in industries that require a step of concentrating and collecting fine particles using a membrane or a step of concentrating a protein chamber. It can be used for concentration / removal in bioprocesses such as fine inorganic particles, viruses, cells, bacteria, and yeast. For example, in the production process of food and cosmetics in addition to biopharmaceuticals, if the fine particles are yeast, it is also used in the fermentation industry. It is also applied to the concentration and removal of fine particles in nanotechnology, where future progress is expected.

Typical example of the module of the present invention

Fig. 1a: Schematic diagram of the module of the present invention; composed of 3 Pradan sheets and 2 porous flat membrane sheets.
FIG. 1b: Elevated view of the module of the present invention; a view corresponding to observation from a cross-sectional direction of the porous flat membrane sheet.
Fig. 1c: Cross-sectional views in the direction of AA, BB, CC in Fig. 1b; cross-section BB shows the cross-sectional shape of the primary flow path in the region (A) (barrel shape close to a rectangle) .
1. Porous flat membrane sheet, 2; Pradan-like sheet with region (c), and Pradan-like sheet are two plastic plates placed in parallel at regular intervals, and a plurality of strips to maintain this interval This means a corrugated sheet in which plastic thin plates are fused at right angles to a flat plate. It has an outlet 7 for the flow path (secondary side flow path) of the membrane permeation liquid (secondary side liquid) of the sheet . 3; Pradan-like sheet processed to have a region (A), a region (A), and a region (D). 4; Pradano-shaped sheet having a region (c), having a membrane permeate outlet 8; 5: It is comprised by the number of tubes of the number of the inlet tube to area | region (a) and the flow path of area | region (a) and (b). 6: Present only in the sheet 3 at the outlet to the outside system of the flow path of the sheet 3. (A) means the region (A), and is present only in the sheet 3 in the flow passage region where laminarization occurs. The cross-sectional shape of the flow path is a rectangular shape composed of two sides of a flat plate and two sides of a flat membrane sheet, but when a transmembrane pressure difference is applied, the flat membrane sheet is slightly deformed up and down to become a barrel shape. . (A): A region (a) meaning a diffusion region in a hole with flow separation. (C) means a region (c), which is a region present in the sheets 2 and 4 having the outlet 7 or the outlet 8 of the liquid in the membrane permeate storage region . (D) means the region (d) and has the outlet 6 of the primary solution module , which is present only in the sheet 3 .

Claims (3)

    Porous diffusion membranes used in membrane separation processing in which the pressure difference between the membranes is 0.05 atmospheres or less under the condition that the liquid to be treated flows in a laminar flow along the membrane surface of the flat membrane of the membrane separation medium The module includes (a) a channel area for laminating the liquid in a channel having a length of 3 cm or more, and (b) a channel having a length of 6 cm or more that is directly connected to the channel area. Of the four walls that form the surface, two parallel surfaces are smooth solid plates, and the remaining two surfaces are in-pore diffusion regions with flow fractionation composed of the membrane surface of the flat membrane, and (C) a storage area for the diffusion liquid having a plurality of wall portions for partitioning the space portion in a space portion constituted by the back surface of the flat membrane; and (d) a fluid accumulation region in which a plurality of the flow paths are integrated. The two regions (a) and (b) are connected on the same common plane so that the liquid flow in the flow path of the two regions and the membrane surface are substantially the same. Parallel to (A) and (c) are adjacent to and integrated with each other through the flat membrane, and (a), (c) and (d) each have at least one connected to the external system. A pore diffusion membrane separation module for concentration, characterized by having an inlet / outlet.   The flat membrane of (a) according to claim 1 has an average pore diameter of the membrane surface smaller than that of the back surface, the membrane surface smoothness of the membrane is 10 μm or less, and the physical apparent thickness is 100 μm or less. The average pore diameter in the velocity method is 10 μm or less, 10 nm or more, the porosity is 60% or more, the bubble point in water is 0.1 atmosphere or more, and the flat membrane is a nonwoven fabric made of a hydrophilic material or A pore diffusion membrane separation module for concentration, which is a polymer porous membrane, and (a) and (d) are detachable. The space part of the storage area of (c) according to claim 1, claim 2 or claim 3 is also provided with a parallel wall part of (a) and a wall part that exists symmetrically with the flat membrane as a mirror surface. A pore diffusion membrane separation module.

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