WO2019163062A1

WO2019163062A1 - Adsorbent and method for preparing adsorbent

Info

Publication number: WO2019163062A1
Application number: PCT/JP2018/006541
Authority: WO
Inventors: 哲郎上山; 優紀川原; 板山　朋聡; 秀二田邉; 裕人村上
Original assignee: 協和機電工業株式会社
Priority date: 2018-02-22
Filing date: 2018-02-22
Publication date: 2019-08-29
Also published as: JPWO2019163062A1; JP6439084B1; JPWO2019163400A1; JP6831157B2; WO2019163400A1

Abstract

[Problem] To provide: an adsorbent which can reduce the total running cost of a water treatment apparatus while preventing membrane obstruction in a reverse osmosis membrane in advance and extending the usable life of the reverse osmosis membrane by selectively adsorbing specific suspended materials or soluble materials which cause membrane obstruction in the reverse osmosis membrane; and a method for preparing the adsorbent. [Solution] This adsorbent 21 preferably comprises a laminate in which, among thermoplastic resins having an average diameter of about 0.5-10 μm, nylon MXD6 resins are laminated, wherein said laminate has a packing density of about 0.20-0.40 g/mL and a specific surface area of about 0.33-6.54 m²/g.

Description

Adsorbent and method for producing adsorbent

The present invention relates to an adsorbent and a method for producing the adsorbent. Specifically, by selectively adsorbing specific suspended substances and soluble substances that cause the membrane blockage of the reverse osmosis membrane, the membrane blockage of the reverse osmosis membrane can be prevented in advance, and the lifetime of the reverse osmosis membrane The present invention relates to an adsorbent and a method for manufacturing the adsorbent that can reduce the running cost of the entire water treatment apparatus.

Demands for collecting and reusing wastewater are increasing due to the recent increase in water demand. Accordingly, water treatment systems that generate pure water from wastewater are widely used in semiconductor factories and the like. As such a water treatment system, for example, in Patent Document 1, first, an organic substance contained in water to be treated is biologically treated, followed by aggregation and solid-liquid separation treatment, and solid-liquid separation treatment water is suspended by membrane filtration treatment. A water treatment system is disclosed in which pure water is generated through a process of treating water to be treated in a wastewater recycling facility equipped with a reverse osmosis membrane (RO membrane) after removing turbid substances and the like.

Here, the reverse osmosis membrane method using a reverse osmosis membrane is a method of obtaining pure water in which treated water is purified by treating salt water with a reverse osmosis membrane at a high pressure. Specifically, desalted water can be produced by applying a pressure equal to or higher than the osmotic pressure to the water to be treated containing salt such as seawater, brine, or wastewater, and allowing the reverse osmosis membrane to permeate.

When drainage recycling equipment equipped with such a reverse osmosis membrane is operated continuously over a long period of time, the reverse osmosis membrane used in reverse osmosis treatment may clog the membrane (fouling), and the amount of filtered water for the treated water may decrease. is there. The causative substances of this membrane clogging are metal and organic matter derived from wastewater, polymeric organic matter generated by biological treatment in the previous stage, metal-based flocculant injected in the previous stage aggregation and solid-liquid separation processing, and metal derived therefrom and polymer aggregation. A part of the agent is included.

Here, among reverse osmosis membranes, a reverse osmosis membrane made of a polyamide-based material in particular has a high desalting rate and excellent organic matter removal properties, but is prone to organic contamination, so the permeation flow rate tends to decrease. There is. For this reason, before supplying to the reverse osmosis membrane, a method of adsorbing and removing contaminants of the water to be treated using an adsorbent such as activated carbon is sometimes used. Since it is adsorbed by the adsorbent, there is a problem that the amount of adsorbent used increases and the cost increases.

For such a problem, for example, in Patent Document 1, an adsorbent filled with an adsorbent made of activated carbon or zeolite as a raw material is used as a pretreatment for a reverse osmosis membrane in order to remove organic substances contained in seawater or brine. By installing it before the reverse osmosis membrane, the concentration of organic substances reaching the reverse osmosis membrane is reduced by the adsorption reaction by the adsorbent and intake by microorganisms grown on the surface of the adsorbent, thereby reducing the membrane blockage of the reverse osmosis membrane Techniques to do this have been proposed.

However, in a method using an adsorbent made of activated carbon or the like as a raw material, adsorption is performed through the pores, and thus substances other than suspended substances and soluble substances to be removed are also adsorbed by the adsorbent. Therefore, for example, when many components other than suspended substances and soluble substances to be removed are contained in the water to be treated, the adsorbent is frequently replaced because it is adsorbed to the adsorbent including these components. There was a problem that it was necessary and the equipment cost increased.

For this problem, for example, Patent Document 2 discloses a water treatment system in which two reverse osmosis membranes are connected in series. Specifically, a first reverse osmosis membrane is provided in the front stage, a second reverse osmosis membrane is provided in the rear stage, and the concentrated water that has not permeated through the first reverse osmosis membrane is filtered through the second reverse osmosis membrane. It is possible to disperse the burden on the reverse osmosis membrane, prevent deterioration of the reverse osmosis membrane as a whole, and extend the useful life of the reverse osmosis membrane.

Further, Patent Document 3 discloses a water treatment apparatus provided with an adsorbing means using an adsorbent containing a powdery substance obtained by pulverizing a polyamide resin close to a material constituting a reverse osmosis membrane. According to Patent Document 3, since the adsorbent is made of the same polyamide resin as the constituent material of the reverse osmosis membrane, a substance that is easily adsorbed on the reverse osmosis membrane is selectively adsorbed in the adsorbent that is the previous stage. Thus, it is possible to prevent the reverse osmosis membrane from being deteriorated and reduce the amount of the adsorbent used.

JP 2008-73622 A Japanese Patent Laid-Open No. 11-47566 JP 2003-275760 A

However, in the technique disclosed in Patent Document 2 described above, the second reverse osmosis membrane filters concentrated water in which impurities are concentrated, so that the operation burden is large. Therefore, there is a problem that the second reverse osmosis membrane is deteriorated faster than the first reverse osmosis membrane, so that the service life is shortened and the quality of the permeated water obtained is also lowered.

Further, in the technique disclosed in Patent Document 3, the adsorbent uses a pulverized polyamide resin, but the total surface area is not necessarily large, and the amount of the suspended matter to be adsorbed is also adsorbed. It will be limited. For this reason, it is necessary to frequently replace the adsorbent, and the running cost is high, which is not necessarily practical. Furthermore, since powder is used, it is difficult to realize the shape of the product for applying the powder to actual equipment, and the water loss energy becomes too high due to the large pressure loss when water is passed through the powder. There was a problem.

The present invention was devised in view of the above points, and by selectively adsorbing a specific suspended substance or soluble substance that causes the blockage of the reverse osmosis membrane, the reverse osmosis membrane An object of the present invention is to provide an adsorbent capable of preventing membrane clogging and extending the service life of a reverse osmosis membrane and reducing the running cost of the entire water treatment apparatus, and a method for producing the adsorbent. And

In order to achieve the above object, the adsorbent of the present invention comprises a laminate in which a thermoplastic resin having an average diameter of approximately 0.5 to 10 μm is laminated, and the packing density of the laminate is approximately 0.20 to 0.40 g / mL and a specific surface area of about 0.33 to 6.54 m ² / g.

Here, by adopting a thermoplastic resin as the material constituting the adsorbent, it is possible to easily produce fine fibers at a low cost, and also has excellent durability and specific suspended substances and solubility. Substances can be selectively adsorbed.

The average diameter of the thermoplastic resin is approximately 0.5 to 10 μm, the packing density of the laminate in which the thermoplastic resin is laminated is approximately 0.20 to 0.40 g / mL, and the specific surface area is 0.33 to 6 Since the adsorption capacity of the adsorbent can be increased by being .54 m ² / g, a specific suspended substance or soluble substance can be selectively adsorbed in a large amount. For this reason, it is possible to prevent the reverse osmosis membrane installed at the subsequent stage of the adsorbent from deteriorating and maintain the adsorption performance of the reverse osmosis membrane for a long period of time. Furthermore, since the fibers having a small average diameter are laminated, a space between the fibers is appropriately secured, and water permeation due to capillary action also occurs, so that the water flow resistance of the adsorbent can be lowered. Therefore, the water to be treated can be passed through the adsorbent with a small applied pressure. Therefore, the running cost of the whole water treatment apparatus in which the adsorbent is installed can be suppressed.

When the average diameter is larger than 10 μm, the diameter of the fiber constituting the adsorbent is increased, so that the specific surface area of the adsorbent is reduced, so that the adsorption capacity of suspended substances and soluble substances is limited. End up. Therefore, it is necessary to change the adsorbent frequently. Further, since the adsorption reaction time is shortened by reducing the surface area, the treatment performance is reduced, the deterioration of the reverse osmosis membrane installed at the subsequent stage of the adsorbent is accelerated, and the replacement cycle of the reverse osmosis membrane is shortened. For this reason, there exists a possibility that the running cost of the whole water treatment apparatus may rise.

On the other hand, when the average diameter is less than 0.5 μm, there is a manufacturing limit in the melt-blowing method, which is a relatively inexpensive manufacturing method. For example, it is necessary to use an electrospinning method, which may increase the manufacturing cost. is there.

Moreover, in order to make the packing density of a laminated body higher than 0.40 g / mL, it is necessary to adhere | attach fibers to a certain extent, but it is necessary to provide a compression process separately for that purpose, and manufacturing cost rises. There is a fear. Moreover, since the water flow resistance becomes high in the product compressed by such a method, the electric energy required for water flow is increased, and thus the running cost of the entire water treatment apparatus may be increased.

On the other hand, when the packing density is less than 0.20 g / mL, the adsorption capacity of suspended substances and soluble substances by the adsorbent is limited. Therefore, the deterioration of the reverse osmosis membrane installed in the subsequent stage of the adsorbent is accelerated, and the replacement cycle of the reverse osmosis membrane is shortened. Moreover, since the space | gap between fibers becomes large too much, the intensity | strength of an adsorbent becomes weak, it causes the shape loss of an adsorbent at the time of water flow, and there exists a possibility that a treated water quality may deteriorate by being unable to perform a uniform process.

Moreover, in order to make the specific surface area larger than 6.54 m ² / g, it is necessary to make the average diameter of the thermoplastic resin less than 0.5 μm or make the packing density higher than 0.40 g / mL. The melt-blowing method, which is a relatively inexpensive manufacturing method, has a manufacturing limit. For example, it is necessary to use an electrospinning method, which may increase the manufacturing cost.

On the other hand, when the specific surface area is less than 0.33 m ² / g, the adsorption capacity of the suspended substance and the soluble substance by the adsorbent is limited. Therefore, the deterioration of the reverse osmosis membrane installed in the subsequent stage of the adsorbent is accelerated, and the replacement cycle of the reverse osmosis membrane is shortened. In addition, since the adsorption capacity per unit mass of the adsorbent decreases, it is necessary to increase the size of the adsorbent in order to ensure a constant amount of adsorption. There is a possibility that the cost increases and the running cost of the entire water treatment apparatus increases.

Further, when the thermoplastic resin is a semi-aromatic polyamide resin, the semi-aromatic polyamide resin is a material having a benzene ring, so that the adsorption performance of a specific suspended substance or soluble substance can be improved. . Therefore, when an adsorbent is installed upstream of a reverse osmosis membrane with a high proportion of benzene rings as a constituent material, suspended substances and soluble substances adsorbed on the reverse osmosis membrane must be adsorbed in advance by the adsorbent. Therefore, deterioration of the reverse osmosis membrane can be prevented, and the adsorption performance of the reverse osmosis membrane can be maintained for a long period of time.

Further, when the thermoplastic resin is an MXD resin, it is easy to adjust the filling density, and therefore, an adsorbent having a high filling density can be produced. Therefore, it is possible to selectively adsorb a large amount of suspended substances and soluble substances on the adsorbent.

In order to achieve the above-mentioned object, the method for producing an adsorbent according to the present invention comprises injecting a molten thermoplastic resin by an air flow so that the average diameter is approximately 0.5 to 10 μm. And a step of winding the thermoplastic resin fiberized by the melt blowing step under a temperature condition equal to or higher than the glass transition point of the thermoplastic resin.

Here, a step of injecting the molten thermoplastic resin by an air flow and melt-blowing the thermoplastic resin to have an average diameter of about 0.5 to 10 μm is provided. It can be.

When the average diameter is larger than 10 μm, the diameter of the fibers constituting the adsorbent becomes large, which lowers the packing density of the adsorbent and reduces the specific surface area. The adsorption capacity is limited. Therefore, it is necessary to change the adsorbent frequently. In addition, since the adsorption reaction time is shortened by reducing the surface area, the processing performance is reduced and the reverse osmosis membrane installed downstream of the adsorbent is deteriorated in a short time, and the reverse osmosis membrane replacement cycle is short. Become. For this reason, there exists a possibility that the running cost of the whole water treatment apparatus may rise.

On the other hand, when the average diameter is less than 0.5 μm, the melt blow method, which is a relatively inexpensive production method, has production limitations, and for example, it is necessary to use an electrospinning method, which may increase the production cost. There is.

Further, by providing a step of winding the fiberized thermoplastic resin under a temperature condition equal to or higher than the glass transition point of the thermoplastic resin, the crystallization of the thermoplastic resin is advanced at a constant speed simultaneously with the winding. be able to. Thereby, since the crystallization of the thermoplastic resin can be gradually advanced simultaneously with the winding of the fiberized thermoplastic resin, an adsorbent having a high packing density and a large specific surface area can be produced.

Further, in the step of melting the thermoplastic resin, when it is melted at a melting temperature of about 250 to 330 ° C., the injected average diameter can be made into a fine fiber shape of about 0.5 to 10 μm. An adsorbent having a high packing density and a large specific surface area can be produced.

In addition, when the melting temperature is 330 ° C. or higher, decomposition of the heat-sparing resin proceeds and gas is generated, and stable fiberization becomes difficult. Therefore, in such a temperature range, the thermoplastic resin cannot be made into fine fibers, such as an average diameter of 0.5 to 10 μm, and the specific surface area is reduced, so that the adsorbent suspended or soluble substances The adsorption capacity is limited.

On the other hand, when the melting temperature is less than 250 ° C., the thermoplastic resin is insufficiently melted and the average diameter cannot be made into a fine fiber shape of about 0.5 to 10 μm. Therefore, since the total surface area is also reduced, the adsorption capacity of suspended substances and soluble substances in the adsorbent is limited.

The step of melt-blowing the thermoplastic resin involves winding the thermoplastic resin, which will be described later, when the thermoplastic resin is injected with an air flow having a temperature of about 300 to 500 ° C. and a flow rate of about 150 to 300 m / sec. In the step of taking, the thermoplastic resin can be wound up and at the same time, the thermoplastic resin can be gradually crystallized and contracted, so that an adsorbent having a high packing density, a large total surface area, and a low water resistance is manufactured. be able to.

In addition, when the temperature of the air flow at the time of melt-blowing is higher than 500 ° C., decomposition of the heat-sparing resin proceeds and gas is generated, making it difficult to achieve stable fiberization by melt-blowing. In such a temperature range, the thermoplastic resin cannot be made into fine fibers such as an average diameter of 0.5 to 10 μm, so that the specific surface area is reduced and the suspended substance or soluble substance of the adsorbent is reduced. Adsorption capacity is limited.

On the other hand, if the temperature of the air flow at the time of melt blowing is less than 300 ° C., the melted heat-sparing resin is cooled before being formed into a fiber by melt blowing, so that the average diameter is as small as 0.5 to 10 μm. It becomes difficult to make it fibrous. In addition, it is difficult to maintain the temperature at the time of winding above the glass transition point, resulting in an adsorbent with a low packing density, which limits the adsorption capacity of suspended and soluble substances in the adsorbent. End up.

Further, if the flow velocity of the air flow at the time of melt blowing is higher than 300 m / sec, the injected thermoplastic resin is cut before being drawn into fine fibers, and the average diameter is set to 0.5 to 10 μm. Therefore, the adsorption capacity of the suspended substance and the soluble substance of the adsorbent is limited.

On the other hand, if the flow rate of the air flow at the time of melt blowing is less than 150 m / sec, the average diameter of the thermoplastic resin fiberized by injection cannot be made into a fine fiber shape of about 0.5 to 10 μm. For this reason, the packing density of the adsorbent cannot be increased, and the total surface area is also reduced, so that the adsorption capacity of the suspended substance or soluble substance of the adsorbent is limited.

In addition, the step of winding the thermoplastic resin is constant after a predetermined time has elapsed after winding when the surface temperature of the thermoplastic resin during winding is approximately 100 to 150 ° C. The crystallization of the thermoplastic resin can proceed at a rate of Thereby, without melting the laminated body laminated by winding the fiber, it is possible to gradually advance the crystallization after winding, because the entire laminated body shrinks in the radial direction and the length direction, An adsorbent having a high packing density, a large total surface area, and a low water resistance can be produced.

In addition, when the surface temperature of the thermoplastic resin at the time of winding is higher than 150 ° C., the crystallization of the thermoplastic resin at the time of winding is accelerated, so that it is crystallized simultaneously with the winding. For this reason, the shrinkage of the laminate accompanying the crystallization after winding is not promoted, so that the packing density cannot be increased, and the adsorption capacity of the adsorbent suspended substance and the soluble substance is limited.

On the other hand, if the surface temperature of the thermoplastic resin at the time of winding is less than 100 ° C., the crystallization speed of the thermoplastic resin becomes slow, and it takes a long time for the thermoplastic resin to shrink after winding, and the shrinkage rate May fall. As a result, the packing density cannot be increased, and the adsorption capacity of the suspended substance and the soluble substance of the adsorbent is limited.

In addition, after the step of winding up the thermoplastic resin, when it has a step of heating the thermoplastic resin in an oven device under a predetermined temperature condition, the crystallization of the laminated body in which the fibers are laminated is gradually advanced. Since the entire laminate contracts in the radial direction and the length direction, it is possible to produce an adsorbent with a high packing density, a large total surface area, and a low water resistance.

In addition, when the step of winding the thermoplastic resin is followed by the step of passing the thermoplastic resin through warm water at a predetermined temperature, the laminate in which the fibers are laminated is heated by warm water. Crystallization can be further advanced, and the entire laminate shrinks in the radial direction and length direction, so that an adsorbent with a high packing density, a large total surface area, and a low water resistance can be produced. . Furthermore, impurities such as organic substances accumulated in the laminate can be removed by washing by passing warm water.

The adsorbent according to the present invention and the method for producing the adsorbent selectively occlude the membrane of the reverse osmosis membrane by selectively adsorbing a specific suspended substance or soluble substance that causes the membrane occlusion of the reverse osmosis membrane. Can be prevented, the service life of the reverse osmosis membrane can be extended, and the running cost of the entire water treatment apparatus can be reduced.

It is the schematic of the waste water treatment system to which the adsorbent which concerns on embodiment of this invention is applied, (a) is the schematic of a water treatment system, (b) is the schematic of a waste water treatment system. 1A is a perspective view, and FIG. 2B is an XX cross-sectional view of FIG. 1A, illustrating an adsorbent according to an embodiment of the present invention. It is a figure which shows the adsorption body manufacturing apparatus for manufacturing an adsorption body in embodiment of this invention.

Hereinafter, the adsorbent and the method for producing the adsorbent will be described with reference to the drawings for understanding of the present invention.

[Water treatment system]
Fig.1 (a) shows the schematic of the general water treatment system 1 installed in a factory etc., for example. In the water treatment system 1, a part of the treated water W2 flowing out from the tap water (tap water) W1 and the wastewater recycling facility 2 passes through the pure water production apparatus 3 and is produced as high-purity water. Used for applications (product water W21, cooling water W22, washing water W23). The water used in the factory flows into the wastewater treatment facility 4 as factory wastewater W3, a part thereof is discharged as sewage W4, and the remaining part flows into the wastewater recycling facility 2 as wastewater treatment water W5. The wastewater treated water W5 that has flowed into the wastewater recycling facility 2 is recycled after removing suspended substances, and is used again for each application in the factory together with the clean water W1.

[Drainage recycling equipment]
FIG. 1B is a schematic view of the wastewater recycling facility 2 described above. In the wastewater recycling facility 2, an adsorbent 21 according to the present invention is arranged on the upstream side, and a reverse osmosis membrane 22 is arranged on the downstream side in series. The reverse osmosis membrane 22 has a known structure, and specifically includes a membrane separation layer made of a polyamide material. As will be described later, the adsorbent 21 is made of a material having a structure close to the polyamide-based material constituting the reverse osmosis membrane 22, specifically, a polyamide resin.

When the wastewater treated water W5 as the treated water flows into the wastewater recycling facility 2 configured as described above, first, the upstream adsorbent 21 adsorbs to the polyamide-based material among the organic substances contained in the wastewater treated water W5. Suspended substances and soluble substances having the above properties are selectively adsorbed. The wastewater treated water W5 that has passed through the adsorbent 21 subsequently flows into the reverse osmosis membrane 22, and further ionic substances such as salt are removed, and finally, the treated water W2 is out of the system of the wastewater recycling facility 2. To be reused for various purposes in the factory. On the other hand, ionic substances such as salinity in the wastewater treated water W5 separated by the reverse osmosis membrane 22 are discharged out of the wastewater recycling facility 2 and processed as concentrated water W6. Suspended substances and soluble substances selectively adsorbed by the adsorbent 21 are carried out of the system while adsorbed on the adsorbent 21 or used as washing wastewater by regenerating and washing the adsorbent. Is discharged out of the diameter.

At this time, the effluent treated water W5 flowing into the reverse osmosis membrane 22 is quantified by a suspended substance or a soluble substance that is a causative substance of the reverse osmosis membrane 22 due to the adsorbent 21 installed in the preceding stage. Has been removed. Therefore, since the amount of suspended substances and soluble substances adsorbed on the reverse osmosis membrane 22 is suppressed, membrane clogging is unlikely to occur, and the lifetime of the reverse osmosis membrane 22 can be extended.

The above is the overall outline of the water treatment system 1 including the wastewater recycling facility 2 to which the adsorbent 21 according to the present invention is applied. However, the reverse osmosis membrane 22 as described above is not necessarily used as the adsorbent 21 of the present invention. However, the present invention is not limited to the use for the purpose of removing the causative substance of the membrane clogging, but may be used for other purposes. For example, when a forward osmosis membrane is used, such as a drainage concentration / reduction process using a forward osmosis membrane, it is used to reduce the risk of membrane blockage of the forward osmosis membrane and is close to the forward osmosis membrane. It can also be used to prevent membrane clogging of membranes for osmotic pressure power generation. In addition, the adsorbent 21 of the present invention can also be used to selectively adsorb and remove trace substances contained in the water when the wastewater treated water is discharged or when water is taken in the water purification facility. Furthermore, the adsorbent 21 of the present invention can also be used when only the impurities are selectively adsorbed and removed in order to increase the purity in food production, pharmaceutical production, ink production, or the like.

Next, the detailed structure of the adsorbent 21 according to the embodiment of the present invention will be described with reference to FIG.

[Adsorbent]
As will be described later, the adsorbent 21 according to the embodiment of the present invention is manufactured by a melt blowing method, which is a known method of manufacturing a molten thermoplastic resin by drawing it with an air flow, and has become a fine fiber by melt blowing. In order to wind up and form a thermoplastic resin, the thermoplastic resin is composed of a substantially cylindrical laminate 211 having a through hole 212 formed in the center.

Here, the laminate 211 is not necessarily required to be substantially cylindrical. For example, any shape may be used as long as it has a hollow shape such as a square tube or an elliptical tube.

Also, the adsorbent 21 is not necessarily manufactured by the melt blow method. For example, it can be produced by an electrospinning method. However, since the electrospinning method has a high manufacturing cost, the manufacturing method in the embodiment of the present invention will be described based on an example of a melt-blowing method that is a relatively inexpensive manufacturing method.

The adsorbent 21 has an outer diameter d of about 60 to 75 mm and a length l of about 125 to 1000 mm, and the fiber material constituting the laminate 211 has an average diameter of about 0.5 to 10 μm. In addition, as the adsorbent 21 in the embodiment of the present invention, an adsorbent 21 having an outer diameter d of 70 mm and a length l of 125 mm was used.

The thermoplastic resin used as the material of the fiber material is preferably a resin material capable of adjusting the crystallization speed at the time of winding, and as described above, is a polyamide resin, more preferably a semi-aromatic polyamide resin, and particularly an MXD resin. In the embodiment of the present invention, nylon MXD6 resin (manufactured by Mitsubishi Gas Chemical Company, “MX nylon”, grade name “S6001”) is employed as the MXD resin.

In the embodiment of the present invention, an example in which the above-described nylon MXD6 is adopted is shown. For example, nylon 6 resin (trade name “Amilan”, grade name “CM1017” manufactured by Toray Industries, Inc.), recycled nylon 6 Resin (trade name “Tanadine”, grade name “TN200” manufactured by Takayasu Co., Ltd.), nylon 66 resin (trade name “Amilan”, grade name “CM3007” manufactured by Toray Industries, Inc.), recycled nylon 66 resin (Takayasu Co., Ltd.) Product name "Tanadine", grade name "TN720"), recycled nylon 6-MXD resin (manufactured by Takayasu Co., Ltd., trade name "Tanadine", grade name "6N-MXD33"), polyamide resin (Mitsubishi Gas Chemical Co., Ltd.) , “LEXTER”, grade name “8000”), polypropylene resin (manufactured by Sun Aroma Co., Ltd., trade name “SUN ALO” -", Grade name" PLA00A "), polystyrene resin (manufactured by PS Japan Co., Ltd., trade name" PSJ-polystyrene ", grade name" GPPS679 "), polyethylene terephthalate resin (manufactured by Kuraray Co., Ltd., trade name" Kurapet "), grade The name “KS710B”) and the like can be selected and adopted as appropriate.

[Adsorbent manufacturing equipment]
Next, the adsorbent manufacturing apparatus 5 for manufacturing the adsorbent 21 will be described with reference to FIG. The adsorbent manufacturing apparatus 5 mainly includes a melt injection apparatus 51, a hot air apparatus 52, and a winding apparatus 53.

The melt injection device 51 includes a hopper 511 for introducing a thermoplastic resin, a screw 513 that is extruded through a motor 512 while melting the thermoplastic resin introduced from the hopper 511 at a high temperature, and an injection for injecting the molten thermoplastic resin. It consists of an injection nozzle 514.

In addition, a heater (not shown) is built in the melt injection apparatus 51 along the axial direction of the screw 513, and the thermoplastic resin introduced from the hopper 511 is melted at a predetermined temperature by the heater. It is like that.

Furthermore, the injection nozzle 514 is provided with an air inlet (not shown), and the air inlet is connected to an external compressor (not shown). In addition, a pressure reducing valve that controls the air pressure from the compressor, a flow meter that measures the air flow rate, and a regulator that adjusts the air flow rate (for example, a needle valve) are connected between the pipes that connect the compressor to the air heating device. May be.

The molten thermoplastic resin is formed into fine fibers by being sprayed with high-temperature and high-speed hot air when it is injected from the injection nozzle 514.

The warm air device 52 blows warm air at a constant temperature against the fiberized thermoplastic resin, so that the surface temperature of the thermoplastic resin during winding by the winding device 53 described later is equal to or higher than the glass transition point. This is a device for adjusting the temperature so that

Here, it is not always necessary to provide the warm air device 52. Any device may be used as long as the temperature can be adjusted so that the surface temperature of the thermoplastic resin at the time of winding by the winding device 53 is equal to or higher than the glass transition point.

The winding device 53 includes a core bar 531 for winding up the thermoplastic resin that has been melt blown into fine fibers. One end of the core bar 531 is attached to the motor 532, and the motor 532 is rotated according to the number of rotations of the motor 532. It is configured to rotate at a constant rotational speed and to reciprocate along the axial direction of the core bar 531. Note that the distance L between the core bar 531 and the injection nozzle 514 is arranged at a position approximately 15 to 20 cm apart.

Here, the distance L between the core bar 531 and the injection nozzle 514 is not necessarily separated by about 15 to 20 cm. However, as a result of examination by the inventors, by separating the distance L between the core bar 531 and the injection nozzle 514 by about 15 to 20 cm, the thermoplastic resin in the form of fibers is wound around the core bar 531 as described later. The surface temperature at the time of taking becomes the temperature suitable for the crystallization of the thermoplastic resin, and the adsorbent 21 having a high packing density and a large specific surface area can be obtained.

Next, a method for manufacturing the adsorbent 21 using the adsorbent manufacturing apparatus 5 as described above will be described.

<Step of introducing thermoplastic resin into melt injection apparatus (S1)>
First, a predetermined amount of nylon MXD6 resin is introduced into the melt injection apparatus 51 from the hopper 511 as a thermoplastic resin.

<Step of melting thermoplastic resin (S2)>
Next, the charged thermoplastic resin is melted and softened by a heater under a temperature condition of approximately 250 to 330 ° C., and the softened thermoplastic resin is extruded toward the injection nozzle 514 by a screw 513.

Here, the melting condition is not necessarily about 250 to 330 ° C. However, as a result of repeated investigations by the inventors, the average diameter of the thermoplastic resin when it is fiberized is as fine as about 0.5 to 10 μm by melting under a temperature condition of about 250 to 330 ° C. In addition, the adsorbent 21 having a high packing density and a large specific surface area was obtained for the laminated body 211 after winding.

<Step of fiberizing thermoplastic resin (S3)>
The thermoplastic resin softened by melting is injected together with high-temperature and high-speed hot air from the injection nozzle 514 toward the core bar 531 of the winding device 53. At this time, the temperature of hot air is set to about 300 to 500 ° C., and the flow rate is set to about 150 to 300 m / sec. Thus, by injecting the thermoplastic resin from the injection nozzle 514 with high-temperature and high-speed hot air, the thermoplastic resin can be melt blown into a fine fiber.

Here, it is not always necessary that the hot air temperature is about 300 to 500 ° C. and the flow rate is 150 to 300 m / sec. However, as a result of examination by the inventors, the average diameter of the thermoplastic resin when melt blown is about 0.5 by setting the hot air temperature to about 300 to 500 ° C. and the flow rate to 150 to 300 m / sec. It was able to be set to ˜10 μm.

<Step of winding up thermoplastic resin (S4)>
The thermoplastic resin that has become fine fibers is wound around a core rod 531 that rotates at a constant rotational speed (approximately 45 rpm) and reciprocates at a constant reciprocating speed (approximately 4 to 25 mm / sec). A fiber laminate 211 having a length and a thickness is formed. At this time, the temperature adjustment is performed by the warm air device 52 so that the surface temperature of the thermoplastic resin when being wound by the winding device 53 is approximately 120 to 150 ° C.

Here, the rotational speed of the core bar 531 is not necessarily about 45 rpm, and the reciprocating speed is not necessarily about 4 to 25 mm / sec. However, as a result of the study by the inventors, the surface temperature of the thermoplastic resin at the time of winding is set to a range of 120 to 150 ° C. by using the rotation speed, the forward movement, and the reciprocating speed. However, shrinkage can be achieved by proceeding with crystallization of the laminate, and an adsorbent with a high packing density can be produced.

Further, the core bar 531 does not necessarily need to be reciprocated in the axial direction. For example, by arranging a plurality of injection nozzles 514 along the length direction of the core bar 531, the stacked body 211 can be configured without reciprocating the core bar 531.

<Step of heating the adsorbent (S6)>
When the winding of the thermoplastic resin in the form of fine fibers is completed by the above-described winding process (S5), the adsorbent made of the laminated body 211 is removed from the core bar 531 and heated for a certain time with a heating device such as an oven. Is done.

Here, it is not always necessary to heat the adsorbent 21. For example, after completion of winding in the winding step (S5), when it can be determined that the crystallization of the thermoplastic resin has progressed sufficiently and the laminated body 211 is sufficiently contracted, a heating device is used again. There is no need to heat the adsorbent 21. Therefore, this process (S6) can be suitably implemented according to the temperature conditions in the winding process (S5).

<Step of cleaning the adsorbent (S7)>
If it can be determined that the multilayer body 211 is sufficiently contracted, a certain amount of cleaning water (warm water) is removed in order to remove minute impurities and the like mixed and accumulated in the multilayer body 211 in the winding step (S5). ) Is passed through the adsorbent 21.

Here, it is not always necessary to perform the step (S7) of cleaning the adsorbent 21. In the winding step (S5), when it can be determined that no impurities are mixed in the stacked body 211, this step need not be performed.

Also, it is not always necessary to use warm water as cleaning water. However, when the laminated body 211 constituting the adsorbent body 21 is not sufficiently contracted by passing warm water having a constant temperature through the adsorbent body 21, the laminated body 211 is further contracted by the heating effect of the hot water. Therefore, the packing density of the entire adsorbent 21 can be increased.

As described above, in the present invention, the surface temperature of the thermoplastic resin at the time of winding is equal to or higher than the glass transition point of nylon MXD6 and is in a temperature range where crystallization is moderately promoted. A condition is set. By setting in this way, crystallization of the fine fibrous thermoplastic resin constituting the laminated body 211 can be delayed in the winding stage, and therefore the laminated body 211 that forms the three-dimensional network structure is provided. Can be obtained. Then, as time elapses after the winding is completed, the laminated body 211 having a three-dimensional network structure is gradually crystallized, so that the entire laminated body 211 contracts in the radial direction and the length direction. Along with this shrinkage, the packing density of the laminate 211 is increased, so that an adsorbent having a large specific surface area and a low water resistance can be manufactured.

The adsorbent 21 manufactured by the above manufacturing method will be described based on Table 1 below. In Examples 1 to 5 and Comparative Examples 1 to 4 shown below, nylon MXD6 is used as the thermoplastic resin, and the adsorbent 21 has a diameter of 70 mm and a length of 125 mm. Used and compared.

[Example 1]
The production conditions in the adsorbent production apparatus 5 were set so that the average diameter was 0.52 μm, and the surface temperature during winding was 135 ° C., the packing density was 0.34 g / mL, and the specific surface area was 6.30 m ² / g of adsorbent 21 was obtained.

[Example 2]
The production conditions in the adsorbent production apparatus 5 were set so that the average diameter was 2.44 μm and the surface temperature during winding was 120 ° C., the packing density was 0.29 g / mL, and the specific surface area was 1.34 m ² / g of adsorbent 21 was obtained.

[Example 3]
The production conditions in the adsorbent production apparatus 5 were set so that the average diameter was 3.82 μm and the surface temperature during winding was 115 ° C., the packing density was 0.26 g / mL, and the specific surface area was 0.817 m ² / g of adsorbent 21 was obtained.

[Example 4]
The production conditions in the adsorbent production apparatus 5 are set so that the average diameter is 7.01 μm and the surface temperature during winding is 115 ° C., the packing density is 0.21 g / mL, and the specific surface area is 0.471 m ² / g of adsorbent 21 was obtained.
[Example 5]
The production conditions in the adsorbent production apparatus 5 were set so that the average diameter was 9.98 μm, and the surface temperature during winding was 115 ° C., the packing density was 0.28 g / mL, and the specific surface area was 0.327 m ² / g of adsorbent 21 was obtained.

[Comparative Example 1]
The production conditions in the adsorbent production apparatus 5 were set so that the average diameter was 3.04 μm and the surface temperature during winding was 95 ° C., the packing density was 0.14 g / mL, and the specific surface area was 1.08 m ² / g of adsorbent 21 was obtained.

[Comparative Example 2]
The production conditions in the adsorbent production apparatus 5 were set so that the average diameter was 13.4 μm and the surface temperature during winding was 115 ° C., the packing density was 0.21 g / mL, and the specific surface area was 0.174 m ² / g of adsorbent 21 was obtained.

[Comparative Example 3]
The production conditions in the adsorbent production apparatus 5 were set so that the average diameter was 23.1 μm and the surface temperature during winding was 115 ° C., the packing density was 0.30 g / mL, and the specific surface area was 0.162 m ² / g of adsorbent 21 was obtained.
[Comparative Example 4]
The production conditions in the adsorbent production apparatus 5 were set so that the average diameter was 42.9 μm and the surface temperature during winding was 115 ° C., the packing density was 0.26 g / mL, and the specific surface area was 0.079 m ² / g of adsorbent 21 was obtained.

[Table 1]

From the results of Table 1 above, it can be seen that the adsorbents 21 of Examples 1 to 5 have higher adsorbability of suspended substances and soluble substances than the adsorbents 21 of Comparative Examples 1 to 4. . That is, in Examples 1 to 5, the average diameter is 0.5 to 10 μm, the surface temperature of the thermoplastic resin during winding is equal to or higher than the glass transition point of nylon MXD6, and the crystallization is moderate. Conditions in each manufacturing process are set so as to be a temperature region that advances. In the winding stage, crystallization of the fine fibrous thermoplastic resin constituting the laminate 211 can be delayed, so that the laminate 211 forming a three-dimensional network structure can be obtained. Furthermore, as time elapses after winding is completed, the laminated body 211 having a three-dimensional network structure gradually crystallizes, so that the entire laminated body 211 contracts in the radial direction and the length direction. Accordingly, since the packing density of the stacked body 211 is increased, the adsorbent 21 having a large specific surface area and a high adsorbing ability can be manufactured.

As described above, the adsorbent according to the present invention and the method for producing an adsorbent selectively adsorb a specific suspended substance or soluble substance that causes the membrane clogging of the reverse osmosis membrane. Membrane blockage can be prevented in advance, the service life of the reverse osmosis membrane can be extended, and the running cost of the entire water treatment apparatus can be reduced.

DESCRIPTION OF SYMBOLS 1 Water treatment system 2 Waste water recycling equipment 21 Adsorbent body 211 Laminated body 212 Through-hole 22 Reverse osmosis membrane 3 Pure water production apparatus 4 Waste water treatment equipment 5 Adsorbent body production apparatus 51 Melt injection apparatus 511 Hopper 512 Motor 513 Screw 514 Injection nozzle 52 Temperature Winding device 53 Winding device 531 Core rod 532 Motor W1 Water supply (tap water)
W2 Treated water W21 Product water W22 Cooling water W23 Wash water W3 Factory wastewater W4 Sewage W5 Wastewater treated water W6 Concentrated water

Claims

It consists of a laminate in which a thermoplastic resin having an average diameter of about 0.5 to 10 μm is laminated. The laminate has a packing density of about 0.20 to 0.40 g / mL and a specific surface area of about 0.33 to 6 Adsorbent that is .54 m 2 / g.
The adsorbent according to claim 1, wherein the thermoplastic resin is a semi-aromatic polyamide resin.
The adsorbent according to claim 1, wherein the thermoplastic resin is a nylon MXD6 resin.
Injecting the molten thermoplastic resin by an air flow and melt-blowing the thermoplastic resin to have an average diameter of about 0.5 to 10 μm;
Winding the thermoplastic resin fiberized by the melt-blowing step under a temperature condition equal to or higher than the glass transition point of the thermoplastic resin.
The thermoplastic resin is
The method for producing an adsorbent according to claim 4, wherein the adsorbent is melted at a melting temperature of about 250 to 330 ° C.
The step of melt blowing the thermoplastic resin includes:
The method for producing an adsorbent according to claim 4, wherein the thermoplastic resin is injected with an air flow having a temperature of about 300 to 500 ° C and a flow rate of about 150 to 300 m / sec.
The step of winding the fiberized thermoplastic resin includes:
The method for producing an adsorbent according to claim 4, wherein the surface of the thermoplastic resin is wound under a temperature condition of approximately 100 to 150 ° C.
After the step of winding up the thermoplastic resin,
The method for producing an adsorbent according to claim 4, further comprising a step of heating the thermoplastic resin under a predetermined temperature condition with a heating device.
After the step of winding up the thermoplastic resin,
The method for producing an adsorbent according to claim 4, further comprising a step of passing warm water having a predetermined temperature through the thermoplastic resin.