TWI664016B - Oil water separation device - Google Patents

Abstract

The present invention provides a water-oil separation device suitable for separating an oil-water mixture, comprising: a container and a water-oil separator detachably mounted on a side wall of the container. The oil-water separator includes an oil-water separation membrane comprising: a substrate having a porous structure; a catalytic layer comprising a metal hydroxide and deposited on a surface of the porous structure of the substrate; and comprising a nano a carbon tube, and a hydrophobic oleophilic layer that is catalyzed by the catalytic layer on the surface of the catalytic layer. The oil-water separation device of the present invention has a simple structure and is suitable for mass production, and has an excellent separation effect for oil-water separation.

Description

Oil water separation device

The present invention relates to an oil-water separation device, and in particular to an oil-water separation device having a carbon-water separation membrane on which a carbon nanotube is grown as a water-oil separator.

In recent years, industrial pollution or oily waste water generated by oil leakage has caused a major impact on the environment. Therefore, materials and equipment capable of separating oil and water have been actively researched and developed.

Regarding the oil-water separation technology, techniques that have been widely used include conventional techniques such as gravity separation, centrifugation, electric field method, coagulation method, and absorption method. However, these conventional techniques still fail to achieve excellent oil-water separation efficiency, and cause secondary pollution and an increase in equipment cost.

In view of the technical problems existing in the prior art described above, it is a primary object of the present invention to provide an oil-water separation apparatus incorporating an oil-water separation membrane which has excellent oil-water separation ability and is easy to manufacture.

Another object of the present invention is to provide an oil-water separation device having a hydrophobic and lipophilic oil-water separation membrane. The raw material of the oil-water separation membrane is environmentally friendly and does not cause secondary pollution to the environment when used.

In order to achieve the above object, the present invention provides a water-oil separation device, which is suitable for separating an oil-water mixture, comprising: a container having an accommodating space isolated from the outside, at least one oil-water separator detachably disposed on at least one side wall of the container When the oil-water mixture comes into contact with the oil-water separator from the outside of the container, the oil-water separator only passes the oily substance of the oil-water mixture into the accommodating space, wherein the oil-water separator comprises an oil-water separation membrane, and the oil-water separation membrane has: a substrate having a porous structure, the substrate is made of glass or metal; a catalytic layer comprising a metal hydroxide deposited on the surface of the porous structure of the substrate; and a hydrophobic oleophilic layer comprising a carbon nanotube The catalytic layer is catalytically grown on the surface of the catalytic layer.

In an embodiment of the invention, the oil-water separator further includes: at least one non-return member disposed on a side of the oil-water separation membrane adjacent to the accommodating space, wherein the oily substance passing through the oil-water separation membrane is intended to flow at least When the member is returned, at least one of the non-return members allows only the oily substance to flow into the accommodating space in one direction.

In an embodiment of the invention, at least one oil-water separation membrane is further disposed on the liquid inflow port of the at least one check member.

In an embodiment of the invention, the oil-water separation device further includes: a discharge pipe disposed at a side wall of the container, and discharging the oily substance through the discharge pipe.

In an embodiment of the invention, the substrate is a screen woven from glass fibers or metal fibers.

In an embodiment of the invention, the metal fiber is any one of stainless steel fiber, titanium fiber, iron fiber, and copper fiber.

In an embodiment of the invention, the metal hydroxide is any one of nickel hydroxide, iron hydroxide, and cobalt hydroxide.

In an embodiment of the invention, the carbon nanotubes are grown in a vertical alignment on the surface of the catalytic layer.

In an embodiment of the invention, the carbon nanotube is a multi-walled hollow nanostructure having a diameter of 20 nm and a length of 5 μm.

In an embodiment of the invention, the surface of the carbon nanotube composite has a contact angle with water of 144 degrees or more and a contact angle with the oil of 0 degrees.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings, which are readily understood by those skilled in the art. The invention may be embodied in a variety of variations, and is not limited to the embodiments. The description of the well-known parts is omitted in the following embodiments, and the same reference numerals are used to refer to the same or similar elements.

Referring to FIG. 1 , an oil-water separation device 100 for separating an oil-water mixture according to an embodiment of the present invention includes a container 110 having an accommodating space 112 isolated from the outside; and a water-oil separator 120 detachably disposed in the container 110. On the side wall. The oil water separators 120 may be disposed on a single side wall in a single one; or the plurality of oil water separators 120 may be respectively disposed on different side walls, or may be disposed on the same side wall. In addition, the size of the oil-water separator 120 is not particularly limited. In the embodiment not shown, the oil-water separator 120 may have the same size as the side wall, that is, the water-oil separator 120 directly serves as a container 110. Side wall. The oil-water separator 120 includes an oil-water separation membrane 122. The oil-water separation membrane 122 is a sieve having superhydrophobic and lipophilic properties. When the external oil-water mixture is in contact with the oil-water separation membrane 122, the superhydrophobic-lipophilic property of the oil-water separation membrane 122 is transmitted. The oily substance is adsorbed by the oil-water separation membrane 122, and is guided by the liquid pressure and gravity, and flows through the pores of the oil-water separation membrane 122 into the accommodating space 112 of the vessel 110. In contrast, moisture is not able to pass through due to hydrophobicity, so that the effect of oil-water separation is achieved.

Hereinafter, the structure and manufacturing method of the oil-water separation membrane 122 according to an embodiment of the present invention will be further described with reference to Figs. 2a to 2c. First, as shown in Fig. 2a, the base material of the oil-water separation membrane 122 is a screen woven from the fibers 1210, and the substrate is pre-cleaned and dried. The substrate is not limited to the screen, and may be a substrate having a porous structure. The fiber of the fiber 1210 is made of a material that can withstand a high temperature of 400 degrees or more without melting, and can be any high temperature resistant material, preferably a glass fiber, or a metal made of any one of stainless steel, titanium, iron, and copper. The fiber, more preferably a metal fiber, is preferably a stainless steel fiber. The hole density of the screen is preferably from 100 to 500 mesh as needed.

Next, as shown in FIG. 2b, a layer of metal hydroxide is deposited as a catalytic layer 1220 on the top surface of the fiber 1210 so as not to fill the mesh holes. After the catalyst layer 1220 is formed, the sample is taken out, washed, and dried. The method of depositing a metal hydroxide to form the catalytic layer 1220 is preferably a chemical bath deposition (CBD) method, immersing the fiber 1210 in a solution containing metal ions, and then adding ammonia water as a precipitant. Alternatively, the metal ions are precipitated by metal hydroxide formation by heating the urea solution to release ammonia to deposit on the surface of the fiber 1210. Furthermore, the source of the metal is preferably one of iron (Fe) ions, cobalt (Co) and nickel (Ni), and the concentration of the metal ions in the solution is preferably 0.5 M to 2.0 M, and the reaction temperature is preferably The reaction time which can be 15 to 20 ° C corresponds to the metal used and the concentration of the solution, preferably 3 s to 1 hr.

Next, as shown in FIG. 2c, a sample deposited with a catalytic layer 1220 is placed in a quartz furnace tube for heating, and the metal hydroxide on the surface of the catalytic layer 1220 is converted into nano metal particles by heating at a high temperature of 400 ° C or higher. At this time, a mixed gas of an inert gas/carbon source is introduced, and the carbon source that is introduced is catalyzed and cleaved upon contact with the nano metal particles, thereby generating carbon atoms/molecules and further depositing on the surface of the nano metal particles. Then, the carbon nanotubes are grown on the surface of the catalytic layer 1220 in a vertically aligned manner, that is, a carbon nanotube is grown on the surface of the catalytic layer 1220 by chemical vapor deposition (CVD) to form a carbon nanotube. The hydrophobic lipophilic layer 1230 then completes the hydrophobic oil-oil-repellent oil-water separation membrane 122 on the fiber 1210 in sequence to form the catalytic layer 1220 and the hydrophobic lipophilic layer 1230. The pressure in the quartz tube can be 5 to 100 torr. The inert gas considers a gas which can provide a carbon source stably generating carbon atoms/molecules in a high temperature environment without side reaction, preferably argon (Ar), and the flow rate of the introduction can be 200 to 500 sccm. The carbon source is considered to be a gaseous substance which can be catalyzed and cleaved into carbon atoms/molecules, preferably acetylene (C ₂ H ₂ ), and the flow rate can be 5 to 15 sccm. The heating temperature takes into account the growth rate of the carbon nanotubes, preferably 400 to 650 ° C, and when the temperature is high, there is a faster growth rate.

The metal hydroxide is used as the catalytic layer because the metal layer is used in the catalytic layer in the prior art. However, in the high temperature environment of CVD, the metal element is alloyed with the metal (especially stainless steel) as a substrate to form an alloy. Lose its catalytic effect. Therefore, in order to avoid the generation of alloys, the prior art forms a buffer layer of alumina on the substrate before plating the metal elements, and the formation of the buffer layer and the plating of the metal elements are all performed through a high vacuum device. Then, when the CVD method is carried out to grow the carbon nanotubes, the required temperature is also as high as 700 to 800 ° C. Therefore, when the oil-water separation membrane 122 is produced by a conventional technique, the finished product size is not limited by the size of the high vacuum apparatus. It also increases equipment and energy costs. In contrast, by the description of another embodiment of the present invention, the formation of a metal hydroxide using the CBD method can be performed at atmospheric temperature and at normal temperature, without special equipment, and is not limited by the size of the apparatus. Further, in the CVD method, it is only necessary to start the reaction at 400 ° C, and thus the energy consumption is also reduced.

Further, the method for producing the oil-water separation membrane in the first embodiment of the present invention will be exemplified with reference to the conditions shown in Table 1.

Table 1      Example 1 Example 2 Example 3 Example 4 Hole density (mesh) 300 300 300 300 Nickel sulfate concentration (M) 1 - - - Cobalt sulfate concentration (M) - 0.5 - - Cobalt chloride concentration (M) - - 0.075 Ferric sulfate concentration (M) - 0.5 - Potassium persulfate concentration (M) 0.25 0.25 0.25 - Ammonia concentration (%) 28 28 28 - Urea concentration (M) - - - 0.5 Deposition temperature (°C) 15 15 15 80 Deposition time (min) 2 1 1 30 Quartz tube pressure (torr) 20 20 20 20 Quartz tube temperature (°C) 650 650 650 650 Argon/acetylene flow rate (sccm) 320/10 320/10 320/10 320/10 Catalytic reaction time (min) 20 20 20 10

First, a screen made of stainless steel fibers having a hole density of 300 mesh was provided, and the screen was washed with ultrasonic vibration of acetone and deionized water in sequence, and then dried at 60 ° C in the air.

Next, 4 mL of a 1 M nickel sulfate solution (NiSO ₄ ) was prepared and mixed with 3 mL of 0.25 M potassium persulfate (K ₂ S ₂ O ₈ ) to obtain a nickel ion solution. Soaking the dried sieve in the nickel ion solution, and adding 1 mL of a 28% ammonia aqueous solution at 20 ° C through a CBD method to form nickel hydroxide to form nickel hydroxide and deposit it on the fiber. The topography is formed on the surface to form a nickel hydroxide layer. After standing for 2.5 minutes, the sieve was taken out of the solution, washed with deionized water, and dried at a temperature of 60 ° C in the air. After the step is completed, the surface of the screen is observed.

The above-mentioned screen deposited with nickel hydroxide was placed in a quartz furnace tube, the pressure was controlled at 20 torr and annealed in an argon atmosphere at a temperature of 650 ° C for 5 minutes to gradually convert the surface nickel hydroxide into Nano-nickel metal particles, followed by argon/acetylene (flow rate 320/10 sccm) gas mixture for 20 minutes, acetylene is contacted with nano-nickel metal particles and catalyzed to grow nano-carbon on nano-nickel metal particles The tube forms a hydrophobic oleophilic layer. Thus, an oil-water separation membrane in which a catalytic layer and a hydrophobic lipophilic layer were sequentially formed on a stainless steel mesh was obtained.

Observe the surface of the oil-water separation membrane. The surface of the oil-water separation membrane was further tested for hydrophobic lipophilicity and compared to a screen that was not surface-modified.

Further, referring to the conditions of Table 1, the oil-water separation membranes of Exemplary Examples 2 to 3 were completed in the same manner as in Example 1, and the surface of the oil-water separation membrane was observed in the same manner.

Further, in the example 4, a stainless steel mesh having a hole density of 300 mesh was provided in the same manner as in the example 1.

Next, a cobalt ion solution containing 0.075 M of cobalt chloride (CoCl ₂ ) and 0.5 M of urea was prepared. Soaking the dried stainless steel mesh in the cobalt ion solution, heating to 80 ° C to produce ammonia, reacting cobalt ions to form cobalt hydroxide, and depositing on the surface of the screen to form cobalt hydroxide Floor. After the reaction was added for 30 minutes, the sieve was taken out of the solution, washed with deionized water, and dried at a temperature of 60 ° C in the air.

The above-described screen in which cobalt hydroxide was deposited was placed in a quartz furnace tube, and a catalytic reaction was carried out in the same manner as in Example 1. The time for the catalytic reaction was only 10 minutes and is presented in Table 1.

The produced oil-water separation membrane was passed through a Field-Emission Scanning Electron Microscope (FE-SEM; model: JSM-7610F, manufactured by JEOL Ltd.) and a transmission electron microscope (Transmission Electron Microscopy, TEM). ; Model: JEM-2100F, manufactured by JEOL Ltd.) The growth state of the carbon nanotubes was observed, and the results are shown in Figs. 3a to 3f.

Figures 3a and 3b show low resolution/high resolution FE-SEM images after depositing nickel hydroxide on a stainless steel screen, while Figures 3c and 3d show low resolution/high after growth of carbon nanotubes on stainless steel screens. Analyze the FE-SEM image. It can be observed from Fig. 3c and Fig. 3d that the carbon nanotubes grown by the CVD method have a uniform outer diameter of about 20 nm and a length of about 5 μm. Further, it was observed from the low-resolution/high-resolution TEM images of Figs. 3e and 3f that the carbon nanotubes were multi-walled hollow nanostructures.

Further, in FIGS. 3g to 3i, in the examples 2 to 4, the low-resolution FE-SEM image after the carbon nanotubes are grown on the stainless steel screen can also be observed that the structure is similarly formed on the surface of the screen. Carbon nanotubes.

Next, the hydrophobic and lipophilicity test of the sample was carried out, and the finished sample was lightly placed on the surface of the water to observe whether the sample sank into the water. In addition, a drop of water and oil were dropped on the surface of the sample placed horizontally to observe the contact angle between the water drop and the oil droplet and the surface of the sample, and the results are shown in Figs. 4a to 4c.

As shown in Figure 4a, after the stainless steel mesh without surface modification and surface modification was placed on the water surface, the stainless steel mesh without surface modification was not hydrophobic and then submerged, and the surface modified stainless steel mesh was subjected to The buoyancy generated by the surface hydrophobicity floats on the water surface. As shown in Figures 4b and 4c, when water droplets and oil droplets are respectively dropped on the surface of the oil-water separation membrane, the contact angle of water droplets with the surface is observed to be above 144 degrees (Fig. 4b), and the oil droplets rapidly penetrate into the oil water. In the pores on the surface of the separation membrane, the contact angle was defined as 0 degree (Fig. 4a). It was thus confirmed that the superhydrophobic and lipophilic properties of the oil-water separation membrane were able to absorb oil droplets and repel water droplets.

The oil-water separation membrane described above was installed in the oil-water separator 100 of Fig. 1, and the oil-water separator 100 was placed in an oil-water mixture for oil-water separation test. When the oil-water separator 100 floats on the liquid surface and the oily substance comes into contact with the oil-water separation membrane 122, the oil-soluble substance 511 is adsorbed by the lipophilicity of the oil-water separation membrane 122, and the oily substance is further guided by the liquid pressure and gravity. The pores of the oil-water separation membrane 122 flow into the accommodating space 112, and the water cannot enter the accommodating space 112 because the superhydrophobic repellent of the oil-water separation membrane 122 cannot pass through the pores, thereby achieving the effect of oil-water separation.

When the oily substance in the accommodating space 112 is accumulated to a certain volume, the oily substance can be discharged from the detaching port by disassembling the oil water separator 120.

Then, the oil-water mixture containing gasoline, diesel oil, baby oil, salad oil, or motor oil is passed through the oil-water separation device 100 to which the oil-water separation membrane 122 is attached, and the oil-water separation efficiency is tested, and the separation rate (%) is obtained by the following calculation formula: Rate (%) = Wherein V ₀ represents the volume of the oily substance in the mixture before separation, and V represents the volume of the oily substance collected after the separation.

The results of the separation are shown in Table 2. The oil-water separation membrane 122 was used for oil-water separation, and the separation rates were all above 99%.

Table 2   Oil-water mixture composition Separation rate (%) Gasoline/water 99.8 Diesel/water 99.8 Baby oil/water 99.7 Salad oil/water 99.3 Oil/water 99.5

Through the above description, the present invention provides a hydrophobic and lipophilic oil-water separation membrane 122 which has excellent oil-water separation ability. In addition, due to its simple structure, it is suitable for mass production.

Further, the base material of the oil-water separation membrane 122 is a material having a certain mechanical strength, is not easily damaged during use, and can be recycled and reused, thereby reducing secondary pollution to the environment.

In another embodiment of the present invention, the oil-water separation device 100' may be a stationary oil-water separation device, for example, fixing the oil-water separation device to a predetermined wall surface, and as shown in FIG. 5, on the side wall of the oil-water separation device 100'. The discharge pipe 130 is installed so that the oily substance can be quickly discharged to the waste oil treatment device or the like (not shown) via the discharge pipe 130, so that it is possible to simplify the disassembly of the oil water separator and then dump the oil water separation device in order to discharge the waste oil from the removal port. The complicated process.

In another embodiment of the present invention, as shown in FIG. 6a, the oil-water separation device 200 may further be provided with a check member 124 on the side of the oil-water separation membrane 122 adjacent to the accommodating space 112, when the oil is passed through the oil-water separation membrane 122. When the material is to flow through the check member 124, the check member 124 allows only the oily substance to flow into the accommodating space 112 in one direction, so that the oily substance is caused by the internal liquid pressure in order to avoid excessive accumulation of oily substances in the accommodating space 112. It is larger than the external liquid pressure, and flows out from the accommodating space 112 in the reverse direction. Fig. 6b is a cross-sectional view of Fig. 6a showing the state in which the oily substance flows into the accommodating space 112, and the check member 124 is opened and allowed to flow.

The check member 124 may be any valve member as long as it can flow an oily substance and cannot flow out, and the material of the valve member is not limited. Further, the oil-water separation membrane 122 may be provided separately from the check member 124, and the oil-water separation membrane 122 may be installed on the liquid inlet of the check member 124 (that is, the check member 124 already contains the oil-water separation membrane 122).

Although the above embodiment of the present invention only lists the embodiment in which the oil-water separation membrane 122 is square, the oil-water separation membrane may be arbitrarily changed according to the shape of the side wall of the container 110 or the shape of the flow path of the check member 124, for example, It is a spherical surface, a circle, and the like. Thus, in another embodiment of the present invention, not only a water-water separation device which is simple in manufacturing and manufacturing, but also a function of avoiding backflow of oily substances is provided.

100, 100', 200‧‧‧ oil-water separation device

110‧‧‧ container

112‧‧‧ accommodating space

120‧‧‧Water separator

122‧‧‧ Oil-water separation membrane

124‧‧‧Return component

130‧‧‧Draining tube

1210‧‧‧Substrate

1220‧‧‧ Catalytic layer

1230‧‧‧hydrophobic oleophilic layer

1 is a schematic view of a water-oil separation apparatus according to an embodiment of the present invention; and FIGS. 2a to 2c are schematic views showing the structure of an oil-water separation membrane contained in a water-oil separation apparatus according to an embodiment of the present invention; and FIGS. 3a to 3i are an embodiment of the present invention; An electron microscope image of the oil-water separation membrane contained in the oil-water separation device in the example; FIG. 4a to FIG. 4c are photographs showing hydrophobicity and lipophilicity of the oil-water separation membrane contained in the oil-water separation device according to an embodiment of the present invention; FIG. A schematic diagram of an oil-water separation device of an embodiment; and Figures 6a to 6b are schematic views of a water-oil separation device according to still another embodiment of the present invention.

Claims (10)

An oil-water separation device, which is suitable for separating an oil-water mixture, comprising: a container having an accommodating space isolated from the outside, at least one oil-water separator detachably disposed on at least one side wall of the container, when When the oil-water mixture is in contact with the oil-water separator from the outside of the container, the oil-water separator only passes an oily substance of the oil-water mixture into the accommodating space, wherein the oil-water separator includes an oil-water separation membrane. The oil-water separation membrane has: a substrate having a porous structure, the substrate is made of glass or metal; and a catalytic layer comprising a metal hydroxide directly deposited on the surface of the porous structure of the substrate; And a hydrophobic oleophilic layer comprising a carbon nanotube through which the catalytic layer is catalytically grown on the surface of the catalytic layer. The oil-water separation device of claim 1, wherein the oil-water separator further comprises: at least one non-return member disposed on a side of the oil-water separation membrane adjacent to the accommodating space, wherein When the oily substance of the oil-water separation membrane is to flow through the at least one non-return member, the at least one non-return member allows only the oily substance to flow into the accommodating space in one direction. The oil-water separation device according to claim 2, wherein the at least one oil-water separation membrane is further disposed on the liquid inflow port of the at least one non-return member. The oil-water separation device of claim 1, wherein the oil-water separation device further comprises: A discharge pipe is disposed at a side wall of the container through which the oily substance is discharged. The oil-water separation device according to claim 1, wherein the substrate is a screen woven from glass fibers or metal fibers. The oil-water separation device according to claim 5, wherein the metal fiber is any one of stainless steel fiber, titanium fiber, iron fiber, and copper fiber. The oil-water separation device according to claim 1, wherein the metal hydroxide is any one of nickel hydroxide, iron hydroxide, and cobalt hydroxide. The oil-water separation device according to claim 1, wherein the carbon nanotubes are grown on the surface of the catalytic layer in a vertically aligned manner. The oil-water separation device according to claim 1, wherein the carbon nanotube has a multi-wall hollow nanostructure and has a diameter of 20 nm and a length of 5 μm. The oil-water separation device according to claim 1, wherein the surface of the carbon nanotube composite has a contact angle with water of 144 degrees or more and a contact angle with the oil of 0 degrees.