JPS5857207B2 - Oil-water separation material and method for treating oil-containing water using it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil-water separation material and a method for treating oil-containing water using the same. wood and
The present invention relates to a method of effectively separating oil from oil-containing water using this method.

BACKGROUND OF THE INVENTION With the remarkable industrial development and improvement of people's lives in recent years, water pollution has progressed rapidly and over a wide area, and has become a major social problem.

The largest quantity of this water pollution is oil.In particular, oil pollution in the sea areas around crude oil storage bases caused by tanker ballast water accumulates. There is a strong desire to establish processing technology as soon as possible from the perspective of resource conservation through cyclical reuse.

The main oil-containing wastewater treatment methods currently in use include the parallel plate levitation method (API, PPI, CPI), adsorption method, centrifugation method, flocculation method, and biological treatment method, but none of these methods is perfect. Good and difficult.

This is because the properties of oil-containing wastewater are not uniform, such as floating oil, dispersed oil,
This is largely due to the complex state of emulsified oil.

In this way, oil-containing wastewater contains various forms of oil, so
In order to remove this oil, first, large oil droplets (>60μ) are brought to the surface by flotation treatment, then oil droplets larger than 10μ are separated using a coalescer, and then adsorption, coagulation treatment, or biological Oil droplets smaller than 10μ can be treated by treatment, but these methods require expensive equipment or a large site area, and the treatment effect for particles smaller than 10μ is not necessarily perfect. It is difficult to process oil droplets ranging in size from large to small in the process.

The present inventors have conducted extensive research to resolve the deficiencies of the conventional oil-containing wastewater treatment methods, discovered the excellent oil-containing wastewater treatment ability possessed by three-dimensional coconut shell fiber aggregates, and have completed the present invention.

That is, the oil/water separation material of the present invention is characterized in that it is composed of a three-dimensional aggregate of coconut shell fibers, and the intersecting portions of the coconut shell fibers are adhered and fixed with an ethylene-vinyl acetate-vinyl chloride terpolymer. That is.

Furthermore, the method for treating oil-containing water of the present invention comprises a three-dimensional aggregate of coconut shell fibers, and the intersecting parts of the coconut shell fibers are adhered and fixed with an ethylene-vinyl acetate-vinyl chloride terpolymer. The oil-water separation material is brought into contact with the oil-containing water, and at the same time, air bubbles are introduced into the oil-containing water from below the oil-water separation material and the air bubbles are caused to pass through the oil-water separation material. .

Here, the coconut shell fiber is a fiber obtained from the husk (outer skin part) of a coconut, and the husk usually consists of long fibers, short fibers, and coir dust.

First, the coconut is separated into husks and seeds, soaked in husk water for fermentation and scouring, washed with water and dried, then combed out long fibers and removed short fibers and coir dust to produce coconut shell fibers. .

It is usually commercialized in the form of a crimped rope.

It should be noted that the suitable coconut fruit to be used as a raw material for coconut shell fiber is one whose outer skin is rich in fiber.
nucifera), Cocos butyracea (Cocos
butyracea) etc.] are preferred.

The obtained coconut shell fibers are generally brown or dark brown, have a coarse hair-like feel, and have a fiber length of 10 to 20 CrIL and a diameter of 0.03 to 0.1 crIL.

Next, these coconut shell fibers are randomly intertwined and intertwined three-dimensionally, and bonded and fixed with the intersecting portion of ethylene-vinyl acetate-vinyl chloride terpolymer, resulting in a three-dimensional aggregate of coconut shell fibers. is obtained.

The fibers are usually entangled by manually loosening the coconut shell fibers, but they may also be intertwined appropriately using a machine.

As the adhesive for bonding and fixing the fibers to each other, an ethylene-vinyl acetate-vinyl chloride terpolymer is used.

Assuming that an adhesive with a solid content of 50% is used, the amount of adhesive used is usually 100 g per 100 g of coconut shell fiber.
P to 40C1, preferably coconut shell fiber 1
100i to 2009' per 002.

Coconut shell fibers are treated with an adhesive by intertwining and intersecting the coconut shell fibers, then applying or adhering an adhesive to adhere the intersecting portions of the coconut shell fibers, and then drying and fixing this.

The three-dimensional aggregate of coconut shell fibers obtained by adhesive treatment (hereinafter referred to as fiber aggregate) can be used in its bulk form, but it can also be compressed with a roll or press to form a more dense form. It is preferable to use

The bulk density of the fiber aggregate obtained by compression is usually 0.0
It is in the range of 1 to 0.1, preferably 0.03 to 0.0
It is 4.

The oil-water separation material obtained as described above has lipophilicity to adsorb oil from the oil film in the bubbles when it comes into contact with oil-containing water and bubbles, as described below, and its lipophilicity is Once adsorbed, the oils coalesce into large particles that separate from the oil-water separation material.

In addition, the oil-water separator has an excellent ability to treat oil-containing wastewater, such as having sufficient fiber spacing to allow air bubbles to rise while coming into close contact with the oil-water separator.

Next, the oil-water separation material is installed in an oil-containing wastewater treatment device, and while the oil-water separation material is brought into contact with the oil-containing water, gas is passed through the oil-water separation material in the form of bubbles.

As the bubbles pass through, the oil-containing water gradually becomes cleaner, and the oil content is separated and removed.

After the treatment is completed, the oil-water separation material is removed, or the oil-containing water is removed while the oil-water separation material is left as it is, and new oil-containing water is added to introduce air bubbles to continue the wastewater treatment.

Here, the installation location of the oil-water separation material is usually the water surface of the oil-containing water,
It may be installed underwater or at the bottom of an oil-containing water, but it is preferable to install it in contact with the water surface or at the bottom of an oil-containing water.

The amount of oil-water separation material used depends on the oil content of the oil-containing water and its relationship with the equipment dimensions, but usually the oil-containing water is 100 mA'
0.02 to 2.02 of the oil/water separating material is used, preferably 0.1f to 0.51.

The oil-water separation material is aerated at the same time as it comes into contact with oil-containing water, and air is usually used as the aeration gas, but nitrogen gas, carbon dioxide gas, etc. may also be used depending on the properties of the oil.

Further, the bubble formation of ventilation gas is generally carried out using a porous plate, a perforated plate, a lattice plate, etc.

In general, the larger the amount of aeration, the faster a high oil removal rate can be achieved, and the smaller the amount of aeration, the longer time will be required, but it can be selected appropriately depending on the amount of oil-containing water to be treated.

The oil treatment ability of the oil-water separation material varies depending on the oil content in the oil-containing water, but the oil content is 60% per 12 oil-water separation materials.
Normally, water containing oil of 0 ppm to 11,000 ppm is
~8QOmA' can be processed.

Generally, when this throughput is exceeded, the oil removal rate gradually decreases, so the oil/water separation material can be taken out, the oil content removed, and used repeatedly after drying.

The method for treating oil-containing water of the present invention can treat oil droplets ranging in size from large to small, but it is usually possible to treat oil droplets with a diameter of 1μ or more, and oil droplets with a diameter of 2μ or more can be treated. Preferred for droplet processing.

The oil removal and separation mechanism in the oil-containing water treatment method of the present invention will be explained as follows.

Oil droplets in the waste water that come into contact with the air bubbles due to the formation of air bubbles move to the gas-water interface and rise while forming an oil film at the interface due to diffusion pressure.

When this gas-oil film comes into contact with the coconut shell fibers, a fiber-gas overnight system is generated, the oil migrates onto the fibers, and only the air bubbles rise.

On the other hand, the fibers receive oil from the bubbles that rise one after another, and in the intense disturbance caused by the bubbles and water inside the molded object, the attached oil is pushed up, combines with other attached oil, and passes through the formed object. is formed into large oil droplets that float to the surface of the liquid.

In this case, some of the oil becomes a W2O type emulsion and becomes large particles while coagulating with each other.

As described above, the oil-water separation material of the present invention only temporarily adsorbs oil without reaching adsorption saturation (it acts as a type of coalescer, so a large amount of oil can be treated with a small amount of material).

As described above, the oil-water separation material of the present invention provides the following effects.

(b) Since the intersecting parts of coconut shell fibers are bonded and fixed with ethylene-vinyl acetate-vinyl chloride terpolymer,
The oil separation effect can be significantly enhanced compared to when the intersecting portions of coconut shell fibers are bonded and fixed with natural rubber latex, or when the intersecting portions of coconut shell fibers are not bonded or fixed at all.

Such remarkable effects of the oil-water separation material of the present invention can only be achieved by the combination of coconut shell fibers and the ethylene-vinyl acetate-vinyl chloride terpolymer, and natural fibers other than coconut shell fibers or synthetic If the fibers are similarly bonded and fixed with ethylene-vinyl acetate-vinyl chloride, the remarkable oil-water separation effect of the present invention cannot be obtained.

(b) Since the oil/water separating material is composed of coconut shell fibers,
As described below, when it comes into contact with oil-containing water and air bubbles, it has lipophilic properties to adsorb oil from the oil film in the air bubbles, and as a result, the adsorbed oils coalesce together and form large particles. and is separated from the oil/water separation material.

In other words, it has a function as a coalescer.

←→ Since the oil/water separation material is a three-dimensional aggregate of coconut shell fibers, it has a fiber spacing that allows air bubbles to rise through the separation material while coming into close contact with the separation material, thereby preventing the above-mentioned coalescence of oil particles. ,
Withdrawal is carried out effectively.

(Y) If the oil removal rate of the oil-water separation material decreases, it can be regenerated by simply taking out the oil-water separation material, removing the oil, and drying it, which has the advantage of being able to be used repeatedly.

Moreover, since it is mainly composed of natural coconut shell fibers, it can be incinerated, thereby avoiding air pollution as much as possible.

Further, a large amount of sludge waste is not generated as in coagulation and sedimentation treatment.

(The bulk density of the three-dimensional aggregate of coconut shell fibers is 0.03 to 0.
．． 04 is extremely small, so only a very small amount of oil/water separation material is required, and the processing capacity is extremely large. No change observed.

(f) Since ethylene-vinyl acetate-vinyl chloride terpolymer is used as an adhesive to bond and fix coconut shell fibers to each other, the shape stability of the three-dimensional aggregate is
Water resistance and lipophilicity can be further improved.

Further, according to the method for treating oil-containing water of the present invention, the following effects are further achieved.

As described in (g) and (b), the coconut shell fibers absorb oil from the rising air bubbles, and this oil is combined with other attached oil to form large oil droplets.

In this way, oil is only temporarily adsorbed on the oil-water separation material and does not reach adsorption saturation, so a large amount of oil can be treated with a small amount of material.

(7) Therefore, it is possible to downsize the device, and the site area can be saved.

(S) By using it in combination with other oil adsorbents such as kapok fiber, separated oil droplets can be adsorbed to these oil adsorbents.

(v) Rather than using a simple forced floating method of oil, the bubbles rise in the oil-water separation material, so no convection occurs as the bubbles rise.

Therefore, due to convection, the oil that has risen does not fall again, and the oil-containing water is purified in a short time.

Next, examples of the present invention will be described.

Note that the present invention is not limited to such embodiments, and can be freely modified within the scope of the technical idea of the present invention.

Example 1 Coconut shell fibers twisted in a 0-ply shape are loosened, and in the curled state, small amounts are placed on an air stream and sprinkled on the surface of a flat table. /
A bulky fiber aggregate of m was made.

Next, an ethylene-vinyl acetate-vinyl chloride terpolymer emulsion is prepared, and this is applied or adhered to the fiber aggregate using a known coating device such as a spray, roll coater, flow coater, or knife coater. ,
Then, it was dried by hot air, infrared irradiation, or the like to remove water in the coating solution and form a coating film.

The amount of coating liquid is 4oo as dry solid content? The weight was 0.5 kg per m fiber aggregate.

Moreover, the bulk density was 0.03 to 0.04.

After applying the coating liquid, the dried aggregate is preheated to 80 to 160°C for about 5 minutes using methods such as hot air or infrared rays, and then heated with a heated roll or press of any thickness for about 1 minute. After compression, it was cooled to obtain a sheet-like oil-water separation material.

Example 2 111 parts of water and 51 parts of sodium chloride are placed in a mixer, and about 0.51 part of heavy oil A is added thereto. When the mixture is stirred for 5 minutes, the heavy oil A is completely dispersed and cloudy oil-containing water is obtained.

As a result of particle size distribution measurement, the average particle size of these oil droplets was 2.5μ
The log standard deviation was 0.26.

Inject 75 ml of this oil-containing water into a glass tube with a diameter of 2.1 (1'771) equipped with a glass filter of 3 mm at the bottom.
The liquid column had a height of approximately 21.5 CrIL.

In this glass tube, 0.2 mm of the oil-water separation material produced by the method described in Example 1 was placed, and the top of the separation material was placed about 0.2 mm below the liquid level.
It was fixed at 5-1cIrL.

The length occupied by the separating material was approximately 3 CIrL in the glass tube.

When air was passed through this through a glass filter at a flow rate of 40 rrLl for 1 minute, the oil-containing water began to become clear after about 10 minutes.

After 20 minutes, stop the air, collect sample water 5m/separate liquid F
The mixture was placed in a funnel, 10 m of hydrous carbon tetrachloride was added, and the mixture was vigorously shaken for 5 minutes.

After standing still, the carbon tetrachloride layer separated into two layers was separated, and the carbon tetrachloride layer was separated with E paper.
After filtering, the color of the p solution was compared at 260 nm using hydrous carbon tetrachloride as a blank.

The A heavy oil concentration was determined from the calibration curve to be 20 ppm.

The oil concentration in the oil-containing water determined in the same manner was 400 ppm, and therefore the oil removal rate was 95.0%.

Next, the coconut shell fiber aggregate treated with natural rubber latex,
The oil-impregnated water was treated in the same manner as above using untreated coconut shell fibers and other similar natural and synthetic fiber materials.

The results are shown in Table 1.

As is clear from Table 1, the oil removal rate of the three-dimensional aggregate of coconut shell fibers treated with the terpolymer emulsion is higher than that of the natural rubber latex-treated and untreated coconut shell fibers. However, when other natural and synthetic fibers are used, the oil-water separation effect is significantly reduced.

In addition, fibers other than coconut shell fibers can be ethylene-vinyl acetate-
The vinyl chloride terpolymer emulsion or natural rubber latex was treated in the same manner as above to produce an oil-water separation material, and oil-containing water was treated in the same manner as above.

The results are shown in Table 1A.

As is clear from the iIA table, when fibers other than coconut shell fibers are treated with ethylene-vinyl acetate-vinyl chloride terpolymer emulsion or natural rubber latex,
In either case, it is clear that the oil removal rate is significantly inferior to that of coconut shell fiber.

Example 3 * * The amount of oil-water separation material made of a three-dimensional aggregate of coconut shell fibers treated with the ethylene-vinyl acetate-vinyl chloride terpolymer emulsion produced by the method of Example 1 was changed, and the examples were Changes in oil concentration over a fixed period of time were measured according to the apparatus and method of 2.

The results are shown in Table 2.

As is clear from Table 2, 0.02 f/100rr
Even when using a small amount of oil/water separation material such as TL, the oil concentration can be sufficiently reduced in about 1 hour. The concentration has already decreased to several tens of ppm through treatment, and reaches a concentration of around 10 ppm in about 30 minutes.

It is clear that if a slightly larger amount of oil-water separation material is used, the clarification effect at the initial stage is slightly reduced, but sufficient performance can be achieved by aeration treatment for 30 minutes or more.

Example 4 In the case where the top of the oil-water separation material made of a coconut shell fiber aggregate treated with an ethylene-vinyl acetate-vinyl chloride terpolymer emulsion was set at 1 crfL below the surface of the oil-containing ice water (installed at the top), the oil-water separation material We compared and studied three cases: a case where the material was placed between the surface of the oil-containing ice water and the bottom (center installation), and a case where the bottom of the oil-water separation material was placed 2 cm above the bottom of the oil-containing water (bottom installation).

The results are shown in Table 3.

As shown in Table 3, there is no particular difference in the oil removal rate depending on the location where the oil/water separation material is installed, but the oil removal rate is generally higher when installed at the bottom and the top, and when installed at the center, the oil removal rate is higher. There is a tendency for performance to deteriorate slightly.

Example 5 Using an oil-water separation material made of a three-dimensional aggregate of coconut shell fibers treated with an ethylene-vinyl acetate-vinyl chloride terpolymer emulsion produced by the method of Example 1, the apparatus and method of Example 2 were used. Accordingly, the relationship between aeration amount and oil removal rate was investigated.

The installation position of the oil/water separation material was the top installation method described in Example 4.

The study results are shown in Table 4.

As is clear from Table 4, in general, the larger the amount of aeration, the faster a high removal rate is reached; for example, 94% of the oil can be removed by aeration for 5 minutes.

When the aeration rate is reduced, it tends to take a long time to reach a high removal rate, and in actual cases, it is necessary to set the aeration rate in consideration of the balance between the aeration rate and the amount of processing liquid.

Example 6 An oil/water separation material of 0.7707 P consisting of a three-dimensional aggregate of coconut shell fibers treated with an ethylene-vinyl acetate-vinyl chloride terpolymer emulsion was taken and impregnated with about 500 ppm of oil according to the method described in Example 2. 11.5 ml of water
It was treated for 30 minutes at an aeration rate of rrtl/c4/min, and then the oil-impregnated water was renewed and treated in the same manner.

When the total amount of treated oil-containing water reached 700 m13, the oil removal rate decreased, so the oil-water separation material was taken out and air-dried.

Next, using this dried product, oil-impregnated water was treated again in the same manner as above.

The results are shown in Table 5. Table 5 shows the procedure for air-drying the oil-water separation material after the total amount of oil-containing water treated reaches approximately 700rd.
Although we have shown an example in which air-dried material is used repeatedly, almost the same oil removal effect as when using new oil-water separation material is achieved, and it is clear that used oil-water separation material can be activated by drying. .

In addition, in the case of Table 5, in the first treatment, approximately 0.30
12 was removed, second time 0.318f, third time 0.33
1'? was removed, whereas the dry weight after the first use increased by 0.048 g and by 0.008 P after the second use.The method of the present invention does not simply adsorb oil;
It is understood that this is due to a catalytic action that facilitates the adsorption, coalescence, and separation of oil components.

Example 7 According to the method of Example 2, aeration treatment was performed for 20 minutes using 1.28S' of an oil/water separation material made of a three-dimensional aggregate of coconut shell fibers treated with an ethylene-vinyl acetate-vinyl chloride terpolymer emulsion. The particle size distribution of the oil-containing water sample and the oil-containing ice stock solution before aeration was determined using a Coulter counter, and the removal rate was calculated for each particle size.

The results are shown in Table 6.

Amount of oil-water separation material used - 1,7?7100ml Amount of oil-containing water aeration -11,5 rul/(, ii /min NaC1 concentration -0,
5% Sampling 20 minutes after aeration As shown in Table 6, the oil removal rate depends on the oil droplet size.

The diameter of oil-impregnated water/oil droplets to be treated is generally 1**μ or more, preferably 2 to 3μ or more.

Example 8 The effect of adjusting the oil droplet diameter by sodium chloride described in Example 7 can also be more effectively achieved by using aluminum salts.

Table 7 shows the removal effect by adding aluminum sulfate.

When only 0.05% of aluminum sulfate is added, the average diameter of oil droplets becomes 5.8μ, and the removal rate becomes 94% or more.

Since the aluminum sulfate used is a water-containing substance, a high removal effect can be achieved by adding about 4 ppm of aluminum.

Example 9 Using a glass tube with a diameter of 5crrL, the liquid volume was 600wLI
An oil-water separation material made of a three-dimensional aggregate of coconut shell fibers treated with an ethylene-vinyl acetate-vinyl chloride terpolymer emulsion was subjected to aeration treatment to remove oil-containing water according to the method described in Example 2, except that 3 and 3 were left blank. The results are shown in Table 8i.

It is clear that even if the processing equipment and liquid volume are increased in size as described above, the oil removal of the present invention can be carried out just as effectively.

Example 10 Crude oil was used instead of A heavy oil, and the concentration of thorium chloride was set to 3.
1000 ppm of oil-containing water was added to ethylene-vinyl acetate according to the apparatus and method described in Example 2, except that the
It was treated with an oil-water separation material made of a three-dimensional aggregate of coconut shell fibers treated with a vinyl chloride terpolymer emulsion.

The results are shown in Table 9. Table 9 shows the oil concentration after 20 minutes of aeration, but in reality the oil is clarified by about 10 minutes of aeration, and the method of the present invention produces excellent oil that does not deteriorate, regardless of the type of oil being treated. It is clear that the removal effect is shown.

Claims (1)

[Claims] 1. Consists of a three-dimensional aggregate of coconut shell fibers, characterized in that the intersecting parts of the coconut shell fibers are bonded and fixed with an ethylene-vinyl acetate-vinyl chloride terpolymer. Oil/water separation material. 2. Bringing an oil-water separation material made of a three-dimensional aggregate of coconut shell fibers, in which the intersecting portions of the coconut shell fibers are adhered and fixed with an ethylene-vinyl acetate-vinyl chloride terpolymer, into contact with oil-containing water; And at the same time, a method for treating oil-containing water characterized by introducing air bubbles into the oil-containing water from below the oil-water separation material and allowing the bubbles to pass through the oil-water separation material.