TW201315531A - Seawater desalization pretreatment separation membrane, seawater desalization pretreatment device, seawater desalization device and seawater desalization method - Google Patents

Abstract

The invention provides a seawater desalization pretreatment separation membrane, a seawater desalization pretreatment device, a seawater desalization device and a seawater desalization method, capable of removing transparent exopolymer particles (TEP) at a high removing rate while sustaining a high flux, and constantly supplying sufficient raw water to a reverse osmosis membrane without increasing the pressure. The seawater desalization pretreatment separation membrane of the invention, which is applied to a seawater desalization pretreatment of using a reverse osmosis membrane, is provided with a standard flux 'A' greater than 2 m/d. The definition of the standard flux 'A', in case of performing filtration at a constant flux, a relationship, P2≰1.5×P1, between an average membrane pressure differential P1 that is obtained in an initial period of 30 minutes and an average membrane pressure differential P2 that is obtained in a period of 30 minutes after a period of 120 minutes is elapsed, is the maximum flux. Moreover, in the following expressions, carbohydrate removing rate B = (1 – carbohydrate content of the filtered water/carbohydrate content of the raw water), granular carbon removing rate C = (1 – particulate organic carbon of the filtered water/particulate organic carbon of the raw water), carbohydrate removing rate B or the particulate carbon removing rate C is more than 0.3, preferably more than 0.5, in which particulate organic carbon (POC) is a difference of total organic carbon and dissolved organic carbon.

Description

Separation membrane for seawater desalination pretreatment, seawater desalination pretreatment device, seawater desalination device and seawater desalination method

The present invention relates to a separation membrane for seawater desalination pretreatment which can effectively remove turbidity of seawater, a seawater desalination pretreatment apparatus, a seawater desalination apparatus, and a seawater desalination method.

As one of the desalination treatment methods of seawater, fresh water has been obtained by applying pressure to seawater and passing it through a reverse osmosis membrane (RO membrane, reverse Osmosis Membrane) to obtain fresh water. The reverse osmosis membrane is a semipermeable membrane having ultrafine pores having a diameter of about 0.1 to 0.5 nm, and has a property of allowing only water molecules to selectively pass through without passing impurities such as salt.

However, in seawater as raw water, there are many turbid substances including coarse particles. Therefore, in order to prevent contamination of the reverse osmosis membrane caused by the turbidity, it is usually performed before the treatment of the reverse osmosis membrane to remove the turbidity from the raw water.

As an example of the pretreatment, it is possible to perform sand filtration or filtration using a membrane having a larger pore than the pore of the reverse osmosis membrane, such as microfiltration (MF) or ultrafiltration (UF) and the like. Combination or the like (Non-Patent Document 1).

The term "microfiltration" refers to a method of removing turbidity by passing raw water through a microfiltration membrane (MF membrane) having a pore diameter of about 100 to 1000 nm. Further, ultrafiltration means that the raw water is passed through a pore size of 1 to A method of removing turbidity by an ultrafiltration membrane (UF membrane) of about 100 nm.

Non-Patent Document 1: “Floating Strategy” of the Fukuoka Area Waterway Enterprise Group, [online], [Searched on June 7, 2012], Internet<URL:http://www.f-suiki.or.jp/seawater /facilities/mechanism.php>

However, in seawater, there are about 1 to several ppm of plankton or an adhesive substance called TEP (transparent exopolymer particles) which is secreted extracellularly. The TEP-based main component is a saccharide, and the polymer cross-linked body is infiltrated with water to expand to 100-fold volume of jelly-like particles having a particle diameter of about 1 to 200 μm. The inventors found that the MF film or the UF film is used. When the seawater is filtered, the TEP adheres to the surface of the membrane and expands, further producing fouling (clogging) of the MF membrane or the UF membrane. Further, as the amount of fouling increases, the flux (filter amount per unit area and unit time) rapidly drops.

Therefore, the inventors of the present invention have studied the method of "pre-treating TEP using a filtration membrane (LF membrane) having an average pore diameter of 1 μm or more before filtration by MF membrane or UF membrane," but the LF membrane also has It is not sufficient to cause a decrease in the flux accompanying the above-mentioned fouling at an early stage.

That is, in the previous processing, there is a negative correlation between the removal rate of the TEP and the flux, and if the removal rate is increased, the scale is generated in a shorter time, and the flux is rapidly decreased. Therefore, by increasing the pressure by the decrease in the blending flux, the flux can be kept constant, so that the raw water from which the TEP has been removed is constantly supplied to the RO membrane.

However, if the pressure rises, it is necessary to clean the film with a drug or the like. Therefore, the cost increases. If it is clogged, the film is not returned even if it is cleaned, and the film replacement is necessary. Therefore, the maintenance cost increases. Moreover, if the flux becomes small, a large membrane area is required, and the equipment cost increases. Also, in order to increase the pressure, a pump of higher strength is required, thus incurring additional equipment costs. Further, in terms of pressure resistance of the film, the increase in pressure is also limited.

Therefore, an object of the present invention is to provide a high-flux that can maintain a high flux while removing TEP at a high removal rate, and can supply a sufficient amount of raw water to the RO membrane without desiring a large amount of pressure. A separation membrane for treatment, a seawater desalination pretreatment apparatus, and a seawater desalination method.

The present inventors have considered that "previously, the separation membrane for the prior treatment uses a porous body having a continuous pore, and captures a TEP having a larger diameter than the pore diameter, and the pores are sealed while being trapped to cause fouling, and the flux is lowered." Therefore, it is sought to capture the TEP film and conduct various experiments and research.

As a result, it is known that polytetrafluoroethylene (PTFE) is suitable as the film. In other words, PTFE is a porous body having a "large pore formed by a block of resin distributed in an island shape" and a "fibril structure in which fine fibers are interlaced between the blocks of the resin". A sufficient flux is ensured by a larger aperture, and on the other hand, even when the diameter of the TEP is larger than that of the TEP, the TEP can be captured by the interlaced fine fibers.

Then, the inventors of the present invention use the standard flux A shown below as an index relating to the assurance of flux, and the saccharide removal rate B shown below as an index relating to the removal rate of TEP, based on the specific value. The film was evaluated.

The standard flux A means that when the filtration is performed with a certain flux, the average inter-membrane pressure difference P1 of the initial 30 minutes and the average inter-membrane pressure difference P2 of 30 minutes after 120 minutes elapse may satisfy P2 ≦ 1.5 × P1. The highest value of flux.

Since TEP is a jelly-like particle containing a saccharide as a main component, the saccharide removal rate B is used as an index relating to the removal rate of TEP, and is obtained by the following formula.

Sugar removal rate B = (1 - the amount of sugar in the filtered water / the amount of sugar in the raw water)

In the calculation of the sugar removal rate B described above, the amount of the sugar is determined by quantitatively analyzing the amount of the sugar in each of the organic substances in the water and summing them up. However, since the organic matter in the water is various, the inventors of the present invention have focused on the TOC (Total Organic) for measuring the total amount of carbon (organism) of organic matter in organic matter in water. Carbon: Total organic carbon).

Further, a useful method has been found in which TOC and DOC (Dissolved Organic Carbon) are measured by using a TOC meter for raw water and filtered water, and POC (Particulate Organic Carbon: suspended organic carbon, granular carbon) is obtained as both The difference is based on the obtained POC and the granular carbon removal rate C obtained by the following formula is used instead of the above-described sugar removal rate B as an index relating to the removal rate of TEP.

Granular carbon removal rate C = (1 - POC in filtered water / POC in raw water)

As a result of performing various experiments on the respective indexes, it was found that the standard flux A was 2 m/d or more, and the saccharide removal rate B or the granular carbon removal rate C was 0.3 or more, preferably 0.5 or more. The membrane can remove TEP with high removal rate while ensuring sufficient flux.

Further, m/d represents a filtration flow rate (m ³ ) per unit area (1 m ² ) of one day (day).

The PTFE was evaluated based on the above-mentioned respective indexes. As a result, it was confirmed that the standard film A was about 1.5 m/d, and the PTFE was 2 m/d or more. The PTFE was remarkably excellent in numerical value. Further, as for the saccharide removal rate B and the granulated carbon removal rate C, it was also confirmed that if it is PTFE, the removal rate of 0.4 or more which was not obtained by the previous film material is exhibited, and in this respect, PTFE is also numerically Significantly excellent.

By using a film having a standard flux A of 2 m/d or more and a saccharide removal rate B or a granular carbon removal rate C of 0.3 or more, preferably 0.5 or more, it is possible to ensure sufficient flux while High removal rate for TEP removal.

The above evaluation results are not limited to the PTFE film, and it is considered that the same evaluation result can be obtained as long as it is a porous body having a large pore structure and a fibril structure.

Further, when the value obtained by multiplying the standard flux A by the saccharide removal rate B or the granulated carbon removal rate C is used as an index, the multiplier effect is obtained when the value is 2 or more, and it is extremely excellent. Before processing. PTFE also meets this value. The above value is more preferably 5 or more, still more preferably 10 or more.

The inventions of claims 1 to 18 are based on these findings. That is, the invention of claim 1 is a separation membrane for seawater desalination pretreatment, which is used for treatment before seawater desalination using a reverse osmosis membrane, characterized in that the standard flux A is 2 m/d or more, The standard flux A is defined as "When filtering with a certain flux, the average inter-membrane pressure difference P1 of the initial 30 minutes and the average inter-membrane pressure difference P2 of 30 minutes after 120 minutes have passed P2≦1.5×P1 The highest value of the flux is "", and the sugar removal rate B shown by the following formula is 0.3 or more.

Sugar removal rate B = (1 - the amount of sugar in the filtered water / the amount of sugar in the raw water)

The invention of claim 2 is the separation membrane for seawater desalination pretreatment according to claim 1, wherein the saccharide removal rate B is 0.5 or more.

Further, the invention of claim 10 is a separation membrane for seawater desalination pretreatment, which is used for treatment before seawater desalination using a reverse osmosis membrane, characterized in that the standard flux A is 2 m/d or more, The standard flux A is defined as "When filtering with a certain flux, the average inter-membrane pressure difference P1 of the initial 30 minutes and the average inter-membrane pressure difference P2 of 30 minutes after 120 minutes have passed P2≦1.5×P1 The highest value of the flux is "", and the granular carbon removal rate C shown by the following formula is 0.3 or more.

Granular carbon removal rate C = (1 - POC in filtered water / POC in raw water)

Among them, POC: the amount of organic carbon in the suspension (the difference between the total organic carbon and the dissolved organic carbon)

The invention of claim 11 is the separation membrane for seawater desalination pretreatment according to claim 10, wherein the particulate carbon removal rate C is 0.5 or more.

In addition, the invention of claim 3, wherein the separation membrane for pre-seawater desalination treatment is made of polytetrafluoroethylene.

The invention of claim 4, wherein the separation membrane for pre-seawater desalination treatment has a pore diameter of 1 μm or more.

In the present invention, it is preferred to use a LF film having a pore diameter of 1 μm or more. Here, the pore diameter of the membrane is represented by an average pore diameter. The average pore diameter refers to the pore diameter determined by the bubble point method (air flow method).

Specifically, the IPA bubble point value (pressure) measured using isopropyl alcohol and based on ASTM F316 is set to P (Pa), and the surface tension (dynes/cm) of the liquid is set to γ, and B is set to In the case of a capillary constant, the pore diameter means a diameter d (μm) represented by the following formula. Further, the average pore diameters of the MF membrane, the UF membrane, and the like are also the same.

d=4Bγ/P

The LF membrane has an average pore diameter of 1 μm or more, so that the flow rate (flux) per unit membrane area can be increased, and on the contrary, a smaller apparatus can be used to obtain a desired treatment amount. The smaller the average pore size of the LF film, the more the smaller particles can be removed, and the removal rate of the organic particles such as turbidity or TEP in the pretreatment is improved. On the other hand, the smaller the average pore diameter of the LF film, the smaller the flow rate (flux) per unit membrane area becomes. Therefore, the optimum pore diameter is selected in consideration of the removal rate required for organic particles such as turbidity or TEP and the flow rate (flux) per unit membrane area.

The invention of claim 5, wherein the separation membrane for seawater desalination pretreatment is not hydrophilized.

When the film is a polymer film (hydrophobic polymer film) made of a hydrophobic material such as a PTFE film, in general, in order to improve the affinity with the liquid to be treated, for example, a hydrophilic compound such as vinyl alcohol can be used. The surface cross-linking method hydrophilizes the PTFE film.

However, the inventors of the present application have found that when used as a separation membrane for pretreatment, high-flux can be ensured by not performing hydrophilization processing for crosslinking and immobilizing a hydrophilic material on the surface of the membrane. Sugar removal rate or granular carbon removal rate.

Further, unlike such processing, it is preferred to use a "hydrophilization method in which a film is brought into contact with a hydrophilic alcohol before the liquid to be treated is passed, and the surface of the film is covered with a hydrophilic alcohol (including pores)". deal with. Examples of the hydrophilic alcohol include ethanol and propanol, and in particular, isopropyl alcohol can be preferably used.

The invention of claim 6 and 15 is a seawater desalination pretreatment apparatus characterized by using a separation membrane for seawater desalination pretreatment according to claims 1 and 10 as a filtration membrane.

Since the separation membrane for seawater desalination pretreatment which can sufficiently remove the organic matter and sufficiently suppress the decrease in the flux is used, a sufficient amount of the raw water from which the organic matter has been removed can be stably supplied to the seawater desalination apparatus.

The invention of claim 7 and 16 is a seawater desalination pretreatment apparatus of the sixth and fifteenth patent application, wherein the use of the separation membrane for pretreatment of seawater desalination having the scope of claims 1 and 10 is used. After the treatment means, a treatment means using a microfiltration membrane or an ultrafiltration membrane is provided.

By further arranging a microfiltration membrane or an ultrafiltration membrane having a smaller pore size, it is possible to provide a seawater desalination pretreatment apparatus having excellent filtration characteristics, which can further remove fine turbidity other than the organic matter removed by the separation membrane for seawater desalination pretreatment. quality.

The invention of claim 8 and 17 is a seawater desalination apparatus characterized by having a seawater desalination pretreatment apparatus according to claims 6 and 15 and a desalination treatment apparatus using a reverse osmosis membrane.

By using a seawater desalination pretreatment apparatus excellent in filtration characteristics, it is possible to supply raw water in which organic matter is sufficiently removed, so that a seawater desalination apparatus can be provided which can be removed even after a long period of time by a desalination treatment apparatus using a reverse osmosis membrane. In the case of salt treatment, it is also possible to suppress the occurrence of scale on the RO membrane.

The invention of claim 9 and 18 is a seawater desalination method characterized in that the raw water filtered by the seawater desalination pretreatment apparatus according to Items 6 and 15 of the patent application scope is desalted by a reverse osmosis membrane method.

Since the raw water in which the organic substance is sufficiently removed is subjected to desalting treatment, even when the desalting treatment is carried out for a long period of time, it is possible to suppress the occurrence of scale on the RO membrane.

According to the present invention, high-flux can be maintained while removing TEP at a high removal rate, and a sufficient amount of raw water can be constantly supplied to the RO membrane without increasing the pressure.

Hereinafter, the present invention will be described based on embodiments with reference to the drawings.

Separation membrane

First, the separation membrane for seawater desalination treatment of the present embodiment will be described. Fig. 1 is a view for explaining a separation membrane of the embodiment. Fig. 1(a) is a schematic view showing the separation membrane in a plane.

The separation membrane of the present embodiment is a porous membrane made of PTFE, and as shown in Fig. 1(a), the plurality of nodule portions 1 and a plurality of fine fibers (fibrils) having a thickness of 1 μm or less in which the nodule portions 1 are connected to each other are used. In the third embodiment, a plurality of pores 2 are formed between the respective nodule portions 1.

Fig. 1(b) is a schematic view showing a state in which the jelly-like object M is captured by the structure of the nodule portion 1 and the fine fibers 3. Since the fine fibers 3 are randomly interlaced in the plane direction and the thickness direction, even if the pore diameter of the pores 2 is large, the entire thickness direction of the film can be surely captured and the sugar-based composition is jelly-like. carbon. By removing the jelly-like carbon, the total amount of carbon (TOC) in the raw water is reduced, wherein the granular carbon (POC) is reduced. Thereby, for example, the film of 5 m/d can filter the sugar at a high removal rate while maintaining a high throughput as compared with the previous separation membrane of about 1.5 m/d.

2. Determination of flux

The flux is determined to be a flux that satisfies P2≦1.5×P1 between the average inter-membrane differential pressure P1 of the initial 30 minutes and the average inter-membrane differential pressure P2 of 30 minutes after 120 minutes of filtration by a certain flux. The highest value is set to standard flux A.

3. Determination of removal rate

Next, a method of measuring the removal rate will be described. The removal rate is usually evaluated by the sugar removal rate, and the granular carbon removal rate may be evaluated in place of the sugar removal rate from the viewpoint of the easiness of measurement.

(1) Sugar removal rate

The sugar removal rate is expressed by the following formula, and the amount of sugar in the filtered water and the amount of the sugar in the raw water are measured by sugar analysis:

Sugar removal rate = 1 - the amount of sugar in the filtered water / the amount of sugar in the raw water.

Specifically, a sugar analyzer, for example, a sugar analyzer ICS-3000 manufactured by Dionex Co., Ltd., which has an electrochemical detector, is used to quantitatively analyze various sugars in water, and the sum thereof is expressed in ppm.

(2) Granular carbon removal rate

The granular carbon removal rate is expressed by the following formula, and the POC system in the filtered water and the raw water is calculated in the following order:

Granular carbon removal rate = 1 - POC in filtered water / POC in raw water.

I. The TOC of the sample (raw water and filtered water) was measured by TOC.

II. The sample was filtered with a filter having a pore size of 0.1 μm (by which 100% of the POC was removed and only DOC remained in the filtered water).

III. The DOC contained in the filtered water was measured by a TOC meter.

IV. Calculate the POC based on the measured TOC and DOC by the following formula:

POC=TOC-DOC.

In the above, TOC indicates the total amount of carbon in the organic compound present in the raw water (Total Organic Carbon), and DOC indicates the amount of carbon in the organic compound present in the filtered water (Dissolved Organic Carbon). POC indicates the removed particulate carbon (Particulate Organic Carbon).

Further, the TOC is measured by a combustion oxidation non-dispersive infrared absorption method. Specifically, the platinum is used to burn the organic matter with high purity air or oxygen at a high temperature. The concentration of carbon dioxide produced by combustion was measured by a gas analyzer, and TOC was measured. As the TOC meter, for example, the TOC-Vc series manufactured by Shimadzu Corporation is used.

4. Seawater desalination device

Next, the desalination device will be described. The seawater desalination apparatus shown in Fig. 2 is composed of a pretreatment apparatus 11 and a desalination apparatus 10 for demineralizing pretreated seawater. The arrow in the figure indicates the flow of water as the object of treatment, and a pump is disposed in the front stage of the pretreatment device 11.

(1) Pretreatment device

The pretreatment apparatus 11 is provided with the separation membrane of the above structure. It can be configured by filtering only one stage of the separation membrane described above, or as the first pretreatment apparatus including the separation membrane having the above configuration, and the ultrafiltration using the UF membrane or the microfiltration using the MF membrane. 2 The pre-processing device is configured by filtering two stages of the pre-processing device. Even if the first-stage filtration has a sufficient effect of removing the sugar, it is effective in reducing the membrane area of the entire pretreatment apparatus, but it is possible to increase the filtration of the object to be further removed by performing two-stage filtration. degree.

(2) Desalination device

The desalination apparatus 10 has a reverse osmosis membrane having a pore diameter of about 1 to 2 nm. The desalination apparatus 10 may be composed of a spiral reverse osmosis membrane or a tubular reverse osmosis membrane, or may be composed of a hollow fiber membrane, and a structure for treating a large amount of seawater must be formed.

In the seawater desalination apparatus configured as described above, first, the seawater is passed through the separation membrane by the pretreatment apparatus 11, and the organic turbidity or the inorganic solid matter in the seawater is filtered and removed. Then, the seawater from which the organic turbidity or the inorganic solid matter has been removed by the previous treatment device 11 is desalted by the desalination device 10 to obtain fresh water.

When the capacity of the pretreatment device 11 or the desalination device 10 is lowered due to long-time operation, the backwashing can be performed to restore the ability, and the sea salt desalination treatment can be repeatedly used.

The seawater desalination pretreatment apparatus 11 using the separation membrane of the present invention filters and removes organic turbid or inorganic solids in seawater by the separation membrane. Therefore, the clogging in the desalination apparatus can be effectively prevented, the desalination apparatus can be miniaturized, and the desalination cost can be reduced.

[Examples]

Hereinafter, a treatment apparatus before using the separation membrane of the present invention will be described based on examples.

(Example 1)

In the present example, the evaluation of the separation membrane was carried out using the granular carbon removal rate.

Filter

Using seawater as raw water, filtration was carried out using a hydrophilic TT method prior to use of the separation membrane of the present invention. Here, the hydrophilic TT method is a method in which a treatment method of a membrane having a fibril structure used in the present invention is named, and a hydrophilic polymer is surface-crosslinked to a hydrophilic membrane (PTFE-made LF membrane). ) is called "hydrophilic TT film", and TT is named after the first letter of TEP Trap. The following "hydrophobic TT method" is a method in which a hydrophobic film which is not subjected to hydrophilization processing is used (the hydrophilization treatment using an alcohol is first performed).

(1) Hollow fiber module

A hollow fiber membrane module provided with a PTFE hollow fiber membrane (Poreflon (registered trademark), model: TBW-2311-200) having a fibril structure was used. The details of the hollow fiber membrane module are as follows.

Standard flux: 10 m/d

Hollow fiber membrane: 360 roots

Effective length 1000 mm

Hollow fiber outer diameter 2.3 mm

Hollow fiber inner diameter 1.1 mm

Hollow fiber membrane thickness 600μm

Aperture 2.0μm (average particle blocking ratio is 90% or more)

Porosity 70%

Here, the porosity = 100 × {1 - (hollow fiber resin volume cc) / total hollow fiber volume cc)}

Hollow fiber resin volume = hollow fiber weight g / PTFE density

Total hollow fiber volume = hollow fiber cross-sectional area cm ² × length cm

(2) Filter conditions

Pressure: Filtration at a pressure of 50 kPa.

2. Determination of flux and removal rate

(1) Measuring method

I. Determination of flux

The flux is measured based on the amount of filtered water accumulated in the graduated cylinder for a certain period of time.

II. Determination of granular carbon removal rate

The particulate carbon removal rate was measured using a TOC meter (total organic carbon meter) of a TOC-Vc combustion catalyst oxidation method manufactured by Shimadzu Corporation. Furthermore, bauxite, aluminum and iron were also analyzed as a reference.

(2) Measurement results

I. Flux

The flux is 10 m/d.

II. Removal rate

The measurement results are shown in Table 1.

According to Table 1, the POC system was removed from 0.23 ppm to 0 ppm, that is, removed at a granular carbon removal rate of 1.0. Furthermore, it is confirmed that bauxite, aluminum, and iron can also be removed.

As described above, when the separation membrane for seawater desalination treatment of the present invention is used, the flux can be increased, and the removal rate can be further improved.

(Example 2)

In the present example, the evaluation of the separation membrane was carried out using the sugar removal rate.

Filter

The seawater along the coast of Shizuoka City, Shizuoka Prefecture is used as the raw water, and is filtered using a hydrophilic TT method and a hydrophobic TT method prior to the separation membrane of the present invention. Further, for comparison, filtration was carried out using a wire mesh of 2 μm mesh. The same as Example 1 except for the measurement below.

2. Determination

(1) Determination of sugar removal rate

The removal rate of TOC and galactose and glucose was determined by sugar analysis. Specifically, the analysis was performed in the following order.

a. Preparation of the sample

A sample of 980 mL (ml) was lyophilized in portions and thoroughly washed with water to make it accurately 100 mL.

b. Hydrolysis

1 mL of the prepared sample and 1 mL of 4 mol/L trifluoroacetic acid were mixed, and after cooling under reduced pressure, the mixture was heated at 100 ° C for 3 hours to carry out hydrolysis.

After standing to cool to room temperature, the solvent was distilled off by a centrifugal evaporator, and 1 mL of water was accurately added and irradiated with ultrasonic waves.

This solution was placed in a filter unit (0.45 μm) to which an ion exchange resin was added, and centrifuged (10000 rpm) for 1 minute to prepare a sample solution.

c. Preparation of standard solution

10 mg of arabinose, glucose, galactose, fructose, mannose and rhamnose were added to the water to make it exactly 50 mL. Accurately take 5 mL of this solution and add water to make it exactly 50 mL to make a standard solution. Standard solution 1 (about 0.2 μg/mL, respectively), standard solution 2 (about 1 μg/mL, respectively), and standard solution 3 (about 5 μg/mL, respectively) were prepared by accurately diluting the standard solution with water.

d. Measurement conditions

Sugar Analyzer: manufactured by Dionex, Japan, ICS-3000

Detector: electrochemical detector

Column: CarboPacPA10 (4 mmI.D×250 mm)

Column temperature: a certain temperature around 25 ° C

Mobile phase A: 10 mmol/L sodium hydroxide solution

Mobile phase B: 200 mmol/L sodium hydroxide solution

The gradient conditions are shown in Table 2.

Flow rate: 1 mL

Injection volume: 25μL

(2) Measurement result of removal rate

The results are shown in Table 3.

As can be seen from Table 3, the saccharide removal rate was calculated as follows, and galactose and glucose were preferably removed as compared with the metal wire mesh.

Sugar removal rate B = (1 - the amount of sugar in the filtered water / the amount of sugar in the raw water)

Sugar in seawater: 0.021+0.031=0.052 ppm

Hydrophilic TT filtrate: 0.012+0.022=0.034 ppm

In hydrophobic TT filtrate: 0.006+0.012=0.018 ppm

therefore,

The removal rate of hydrophilic TT sugar B=(1-0.034/0.052)=0.34

Sugar removal rate of hydrophobic TT B=(1-0.018/0.052)=0.65

As described above, according to the present invention, the organic turbidity can be removed with high efficiency, and clogging of the desalination apparatus can be prevented for a long period of time, and the cost can be reduced. Moreover, it is understood that this effect is large in the hydrophobic TT method as compared with the hydrophilic TT method.

The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments. The above embodiments can be variously modified within the scope and equivalent of the present invention.

1. . . Nodule

2. . . Fine hole

3. . . Fine fiber

10. . . Desalting device

11. . . Pretreatment device

M. . . Object

Fig. 1 is a view showing a separation membrane of the present embodiment, (a) is a schematic view showing a separation membrane in a plane, and (b) is a schematic view showing a state in which a jelly-like object M is captured by a structure of a nodule portion and a fine fiber. .

Fig. 2 is a block diagram showing the configuration of a seawater desalination apparatus including a processing apparatus before using the separation membrane of the present invention.

Claims (18)

A separation membrane for pretreatment of seawater desalination is used for pretreatment of seawater desalination using a reverse osmosis membrane; wherein the standard flux A is 2 m/d or more, and the standard flux A is defined as: filtering with a certain flux When the average inter-membrane differential pressure P1 of the initial 30 minutes and the average inter-membrane differential pressure P2 of 30 minutes after 120 minutes have elapsed, the highest value of the flux of P2 ≦ 1.5 × P1 is satisfied; and the following formula The sugar removal rate B is 0.3 or more, and the sugar removal rate B = (1 - the amount of sugar in the filtered water / the amount of the sugar in the raw water). The separation membrane for pretreatment of seawater desalination according to the first aspect of the invention, wherein the saccharide removal ratio B is 0.5 or more. The separation membrane for seawater desalination pretreatment according to the first aspect of the invention, wherein the separation membrane for seawater desalination treatment is made of polytetrafluoroethylene. The separation membrane for seawater desalination pretreatment according to the first aspect of the invention, wherein the separation membrane for seawater desalination treatment has a pore diameter of 1 μm or more. The separation membrane for seawater desalination pretreatment according to the first aspect of the invention, wherein the separation membrane for pre-seawater desalination treatment is not hydrophilized. A seawater desalination pretreatment apparatus using the separation membrane for seawater desalination pretreatment of the first application of the patent scope as a filtration membrane. The seawater desalination pretreatment apparatus according to claim 6 of the patent application, wherein, before using the pretreatment means for the separation membrane for pre-seawater desalination treatment of claim 1 of the patent application, before using the microfiltration membrane or the ultrafiltration membrane Means of treatment. A seawater desalination device having a seawater desalination pretreatment device according to claim 6 and a desalination treatment device using a reverse osmosis membrane. A seawater desalination method is a desalination treatment of raw water filtered by a seawater desalination pretreatment device according to item 6 of the patent application scope by a reverse osmosis membrane method. A separation membrane for pretreatment of seawater desalination is used for pretreatment of seawater desalination using a reverse osmosis membrane; wherein the standard flux A is 2 m/d or more, and the standard flux A is defined as: filtering with a certain flux When the average inter-membrane differential pressure P1 of the initial 30 minutes and the average inter-membrane differential pressure P2 of 30 minutes after 120 minutes have elapsed, the highest value of the flux of P2 ≦ 1.5 × P1 is satisfied; and the following formula The granular carbon removal rate C is 0.3 or more, and the granular carbon removal rate C=(1 - POC in filtered water/POC in raw water), wherein POC: suspended organic carbon amount (total organic carbon amount and dissolved organic carbon) The difference between the amounts). The separation membrane for pretreatment of seawater desalination according to claim 10, wherein the particulate carbon removal rate C is 0.5 or more. The separation membrane for pretreatment of seawater desalination according to claim 10, wherein the separation membrane for pretreatment of seawater desalination is made of polytetrafluoroethylene. The separation membrane for seawater desalination pretreatment according to claim 10, wherein the separation membrane for pre-seawater desalination has a pore diameter of 1 μm or more. The separation membrane for pretreatment of seawater desalination according to claim 10, wherein the separation membrane for pretreatment of seawater desalination is not hydrophilized. A seawater desalination pretreatment apparatus using the separation membrane for pre-seawater desalination treatment of claim 10 as a filtration membrane. The seawater desalination pretreatment device according to claim 15 of the patent application, wherein, before using the pretreatment means for the separation membrane for seawater desalination treatment of claim 10, before using the microfiltration membrane or the ultrafiltration membrane Means of treatment. A seawater desalination device comprising a seawater desalination pretreatment device according to claim 15 and a desalination treatment device using a reverse osmosis membrane. A seawater desalination method is a desalination treatment of raw water filtered by a seawater desalination pretreatment device according to item 15 of the patent application scope by a reverse osmosis membrane method.