KR20110058335A - Naa zeolite membrane and method for fabricating the same - Google Patents

Abstract

PURPOSE: A sodium A(NaA) zeolite separating membrane and a method for manufacturing the same are provided to suppress the generation of defects by improving the uniformity of the NaA zeolite separating membrane. CONSTITUTION: An alumina-based raw material, a silica-based raw material, sodium hydroxide are dissolved in water to obtain an aqueous solution. The aqueous solution is mixed to obtain a hydrothermal solution(S100). NaA zeolite powder is vibrated and pulverized under a wet condition to implement a centrifugal process. Seed crystal slurry is prepared. The seed crystal passes through a support to be attached on the surface of the support(S120). The hydrothermal solution is introduced into a hydrothermal reactor, and the support with the seed crystal is immersed in the hydrothermal solution in order to grow a NaA zeolite layer on the surface of the support(S150).

Description

NAA zeolite separator and its manufacturing method {NaA ZEOLITE MEMBRANE AND METHOD FOR FABRICATING THE SAME}

The present invention relates to a NaA zeolite separation membrane and a method for manufacturing the same, and to a technique for increasing the uniformity of the NaA zeolite separation membrane and suppressing defects to have excellent separation performance.

NaA zeolite is an aluminosilicate mineral in which uniform micro pores having a diameter of 4 내에 in a crystal structure have a three-dimensional periodic arrangement, and a part of SiO ₂ is substituted with Al ₂ O ₃ , and is electrically neutral. It is a substance containing the number of moles of Na ions by twice the number of moles of Al ₂ O ₃ substituted for retention.

Such NaA zeolites are widely used as catalysts, adsorbents, ion exchangers and the like in the industry.

Recently, NaA zeolite separators have been prepared by coating a NaA zeolite layer on a plate or tubular porous ceramic or metal support.

Such NaA zeolite membranes are used for separation of effective materials in energy, environment, chemistry, and biomedical fields, or they are intended to be used as membrane reaction processes that hybridize with catalysts to promote the synthesis of active materials. It is increasing and attracts much attention.

In particular, since NaA zeolite membranes have uniform micropores and high polarity, they are currently reported to have excellent performance in the separation of solvents such as water / nonpolar solvent separation and polar / nonpolar solvent separation. It has not been utilized in membrane reactions, etc., which has been found to be closely related to non-zeolitic pore present in NaA zeolite separation layer.

Therefore, stable production of NaA zeolite membranes, that is, NaA zeolite membranes having uniform and non-zeolite pores, that is free of defects, has been recognized as one of the important technologies in the field of NaA zeolite membranes.

The NaA zeolite separation membranes known to date are hydrothermally treated by attaching NaA zeolite seed crystals having a diameter of 1 to 10 μm to the surface of the support, and then supporting them in a hydrothermal solution made by dissolving alumina-based material, silica-based material, and sodium hydroxide in water. It is manufactured by.

1 is a flowchart illustrating a method of preparing a NaA zeolite separator according to the prior art.

Referring to FIG. 1, first, water glass (10), sodium aluminate (Sodium Aluminate, 20), and sodium hydroxide (Sodium Hydroxide, 30) are prepared in an aqueous solution by dissolving in water (40), followed by a mixing process ( S10) to form a hydrothermal solution (Hydrothermal Solution, 50).

Next, a NaA zeolite seed crystal (Seed) 70 having a diameter of 1 to 10 μm is attached to the surface of the porous support 60 (S20). Seed deposition step (S20) is a dip coating method (method of immersing the support in the seed crystal slurry), spray coating method (spray spraying the seed crystal slurry on the porous support), filtration method (passing the seed crystal slurry through the porous support) Method), a rubbing method (a method of rubbing seed crystal powder directly onto a porous support) and the like.

Next, a porous support 80 with seed crystals was placed in a hydrothermal synthesizer on which the hydrothermal solution 50 was loaded, and a NaA zeolite separation layer was formed on the surface of the support through hydrothermal treatment (S30). 90) is synthesized.

At this time, the NaA zeolite seed crystal having a size of 1 ~ 10㎛ has a high particle size, so it is difficult to make a well dispersed slurry state, and thus requires high dispersion control, and synthesizes NaA zeolite powder having some nano-size as seed crystals. Although the use case has been reported, there is a problem that expensive raw materials and a long time highly controlled synthesis process are required to synthesize nano-sized NaA zeolite seed crystals.

In the present invention, NaA zeolite separation membrane, NaA zeolite powder having a diameter of 1 ~ 10㎛ size is used as a seed crystal, but the nano-size NaA zeolite seed crystal is easily prepared by wet vibration milling and centrifugation It is an object of the present invention to provide a NaA zeolite separation membrane having excellent separation performance and a method for producing the same, by which the uniformity of the NaA zeolite layer is remarkably improved and defects are suppressed.

NaA zeolite membrane production method according to the present invention comprises the steps of dissolving alumina-based raw material, silica-based raw material, sodium hydroxide (Sodium Hydroxide) in water to provide an aqueous solution, and mixing the aqueous solution to prepare a hydrothermal solution (Hydrothermal Solution) And wet-pulverizing the NaA zeolite powder and centrifuging to prepare a seed slurry, and passing the seed crystal slurry through the support by vacuum filtration to attach the seed crystal to the surface of the support and the hydrothermal process. And putting the solution in a hydrothermal reactor to support the support on which the seed crystals are attached, and hydrothermal treatment to grow a NaA zeolite layer on the surface of the support.

Here, the alumina-based raw material is characterized in that at least one state of sodium aluminate (Sodium Aluminate), aluminum hydroxide (Aluminium Hydroxide), colloidal alumina, alumina (Alumina) powder, aluminum alkoxide, the silica-based raw material Water glass (Sodium Silicate), silica (Silica) powder, colloidal silica, silicon alkoxide, characterized in that one or more of the state, the addition amount of the silica-based raw material molar converted to silica (SiO ₂ ) The amount is characterized in that the alumina-based raw material is 1 to 3 times the molar amount converted into alumina (Al ₂ O ₃ ).

Next, the addition amount of sodium hydroxide (Sodium Hydroxide) is the molar amount converted from the sodium hydroxide (Sodium Hydroxide) to sodium oxide (Na ₂ O) and sodium oxide (Na ₂ O contained in the alumina-based raw material and silica-based raw material The sum of the molar amounts of _c ) is 2 to 6 times the molar amount of the alumina raw material to alumina (Al ₂ O ₃ ), and the molar amount of water (H ₂ O) in the aqueous solution is the alumina (Al _It is characterized in that 400 to 800 times the molar amount converted to ₂ O ₃ ).

Next, the step of preparing the hydrothermal solution by mixing the aqueous solution is characterized in that for producing for 30 minutes to 48 hours by mixing the aqueous solution at a temperature of 20 ~ 80 ℃. At this time, the NaA zeolite powder is characterized in that using NaA zeolite powder having a diameter of 1 ~ 10㎛.

Next, the wet vibration pulverization is characterized in that it is performed for 1 to 48 hours at 200 ~ 900cycles / min speed using a ceramic ball, the centrifugation is performed for 1 to 60 minutes at 1,000 ~ 15,000rpm speed The seed crystals are characterized in that the diameter of 100 ~ 300nm, the seed crystal slurry is characterized in that the seed crystals are used that is added 0.0005 ~ 0.005% by weight to water.

Next, the vacuum filtration method is characterized in that carried out for 1 to 60 minutes at a pressure of 1 ~ 300torr.

Next, the support is characterized in that the porous ceramic or porous metal having a pore diameter of 0.1 ~ 1㎛, the hydrothermal treatment is carried out for 12 to 48 hours at a temperature of 70 ~ 140 ℃, the NaA The zeolite layer has a thickness of 1 to 20㎛ and is characterized in that it is formed uniformly and densely.

In addition, the NaA zeolite separator according to the present invention is characterized in that it is prepared by the method described above.

Since the NaA zeolite membrane production method according to the present invention uses nano-sized seed crystals, not only the NaA zeolite layer is uniform but also defects are reduced, thereby providing an effect of improving separation performance.

In addition, according to the method for preparing NaA zeolite membrane according to the present invention, the nano-sized seed crystals are obtained by the method of wet vibration milling and centrifugation. It provides an effect that can improve manufacturing reliability.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, only the present embodiments to make the disclosure of the present invention complete, and those skilled in the art to which the present invention pertains. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Throughout the specification, reference numerals refer to like elements.

Hereinafter, the NaA zeolite membrane and the method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a flowchart illustrating a method of preparing a NaA zeolite separator according to the present invention.

Referring to FIG. 2, first, as a raw material for manufacturing a NaA zeolite separator, water glass 110, which is one of silica-based raw materials, sodium aluminate 120, and sodium hydroxide 130, which is one of alumina-based raw materials, is water 140. After dissolving in an aqueous solution, a mixing and aging process (S100) is performed to form a hydrothermal solution (Hydrothermal Solution, 150).

Next, a NaA zeolite seed crystal (Seed, 170) having a diameter of 100-300 nm is attached to the surface of the porous support 160 (S120). At this time, the NaA seed crystal having a nano size is prepared by vibration grinding (S130) and centrifugation (S140) of 1 ~ 10㎛ NaA zeolite powder 190, which is easy to obtain.

Next, the porous support 180 with seed crystals is placed in the hydrothermal synthesizer on which the hydrothermal solution 150 is loaded, and the NaA zeolite membrane 200 is formed by forming a NaA zeolite layer on the surface of the support through hydrothermal treatment (S150). Synthesize

Here, the alumina-based raw material as the raw material for forming the hydrothermal solution 150 may be used in the form of one or more of sodium aluminate, aluminum hydroxide, colloidal alumina, alumina powder, aluminum alkoxide. Can be.

The silica-based raw material may be used in the form of at least one of water glass, sodium silicate, silica powder, colloidal silica, and silicon alkoxide.

At this time, the SiO ₂ / Al ₂ O ₃ molar ratio of silicon oxide (SiO ₂ ) of the silica-based material and aluminum oxide (Al ₂ O ₃ ) of the alumina-based material is appropriately determined according to the composition of the desired NaA zeolite, but preferably It is 1-3, More preferably, it is set to two. That is, the addition amount of the silica-based raw material is preferably such that the molar amount converted into silica (SiO ₂ ) is 1 to 3 times the molar amount converted into alumina (Al ₂ O ₃ ). When the molar ratio is less than 1, the formation of Na zeolite separation layer becomes difficult, and thus the separation membrane performance may be reduced. Can be.

Next, the sodium oxide in the hydrothermal solution (Na ₂ O) are determined by means of a sodium (Na ₂ O) oxide contained in the sodium (NaOH) and silica-based material and the alumina-based raw material hydroxide was added, and sodium oxide in the hydrothermal solution ( The molar ratio of Na ₂ O / Al ₂ O _{3 of} Na ₂ O) and aluminum oxide (Al ₂ O ₃ ) is appropriately determined according to the composition of the desired zeolite, but is preferably 2 to 6, more preferably 4.5 Good to do. That is, the amount of the sodium (Sodium Hydroxide) hydroxide is a molar amount in terms of sodium (Na ₂ O) oxide and the alumina based material and a silica-containing said alumina sum of the molar amount of the sodium (Na ₂ O) oxide contained in the raw material system is preferably a raw material of alumina (Al ₂ O ₃₎ times 2 to 6 in terms of the molar amount. In this case, when the molar amount is added less than 2 times, NaA zeolite separation layer is difficult to form, and the membrane performance may be degraded. When the molar amount is more than 6 times, the separation layer becomes thick and heterogeneous, resulting in poor separation performance. You can.

Meanwhile, the water (H ₂ O) in the hydrothermal solution 150 is determined by the added water 140, silica-based raw material, alumina-based raw material, and water (H ₂ O) contained in an aqueous solution of sodium hydroxide 130, H ₂ O / Al ₂ O ₃ of water (H ₂ O) and aluminum oxide (Al ₂ O ₃ ) in the hydrothermal solution 150 The molar ratio is appropriately determined depending on the composition of the desired NaA zeolite, but preferably 400 to 800, more preferably 600.

Next, in the step of preparing a hydrothermal solution 150 by mixing the aqueous solution (S100), it is preferable to prepare the aqueous solution by mixing for 30 minutes to 48 hours at a temperature of 20 ~ 80 ℃. When the temperature of the aqueous solution is maintained at less than 20 ℃ and less than 30 minutes, the separation performance of the zeolite separation membrane may be lowered, and if more than 48 hours at a temperature exceeding 80 ℃ there is also a problem that can not obtain a uniform zeolite separator .

Next, the support 180 uses a zeolite seed crystal 170 of 100 to 300 nm attached to the surface of the support 160. Here, attaching the zeolite seed crystals to the support is for coating the zeolite crystals in such a way as to grow on the support mainly. Therefore, seed crystals of less than 100 nm are insufficient to obtain an adhesion effect, and if it exceeds 300 nm, the uniformity and compactness of the zeolite separator may be degraded.

Next, the support 160 to which the seed crystal 170 is to be attached (S120) may be any one selected from porous ceramics and a porous metal. Ceramics include materials such as mullite, alumina, silica, titania, zirconia, silicon carbide, and the like, and as the metal, stainless steel, sintered nickel, a mixture of sintered nickel and iron may be used. Ceramics are preferred because they are difficult to elute in the liquid as the material of the support, and alumina is particularly preferred.

Here, it is preferable that the average pore diameter of the support body 160 to which the seed crystals 170 are to be attached (S120) is 0.1 to 1 μm. If the average pore diameter is less than 0.1 μm, the termination crystals are difficult to adhere to the pores of the porous support, which may cause a problem that the zeolite separation layer formed on the support is peeled off. On the other hand, when the average pore diameter exceeds 1 μm, defects such as pinholes may occur in the zeolite separation layer formed on the support.

In addition, the porosity of the support 160 to which the seed crystal 170 is to be attached (S120) is preferably 20 to 50%, more preferably 30 to 40%. If the porosity is less than 20%, the permeation rate becomes small and the permeation flow rate tends to be low. On the other hand, when the porosity exceeds 50%, the self supporting property (mechanical strength) of the support tends to be low. Therefore, when the porosity is 30 to 40%, it is possible to obtain a zeolite separation membrane having sufficiently high permeation flux and mechanical strength.

The shape of the support body 160 to which the seed crystals 170 are to be attached (S120) described above may be tubular, tubular, hollow fiber, plate, multi-tube monolith, or honeycomb ( Honeycomb shape) and pellet shape. The shape may be appropriately determined according to the use and treatment capacity of the NaA zeolite separator.

Next, the zeolite seed crystal 170 preferably has a diameter of 100 ~ 300nm prepared by wet vibration milling (S130) and centrifugation (S140) of 1 ~ 10㎛ NaA zeolite powder (190). If the average seed crystal diameter is less than 100 nm, it is difficult to secure a uniform and desired thickness of the NaA zeolite separation layer due to the small amount of seed crystals attached to and inside the porous support, and if the average seed crystal diameter exceeds 300 nm, The seed crystal may be excessively attached to the surface of the support to cause peeling or non-uniformity of the NaA zeolite layer formed on the support.

Here, the wet vibration mill (S130) for producing the seed crystals 170 is 1 ~ 10 ㎛ diameter NaA zeolite powder 190 put in a ceramic ball, water and vibration-based vibration mill 1 200 ~ 900cycles / min speed It is preferable to perform 48 hours, and more preferably, 24 hours at 500 cycles / min. At this time, the weight ratio of NaA zeolite powder: ceramic ball: water is preferably 1, 90, 20. In the present invention, the batch size was fixed by 20 ml of water. In addition, as the ceramic ball, silicon carbide, silicon nitride, alumina, zirconia, etc. may be used, but it is preferable to use an alumina ball, which is one of the zeolite components, and the diameter of the alumina ball may be about 1 mm.

In addition, the centrifugation (S140) for producing the seed crystals 170 is preferably performed for 1 to 60 minutes at a speed of 1000 ~ 15000rpm, more preferably 10 minutes at 6000rpm. The purpose of centrifugation is to fractionate and remove relatively large particles in the high concentration slurry obtained by the wet vibration grinding (S130). The seed crystal slurry obtained after centrifugation is well dispersed and stored for dilution with water so that the total volume is 200 ml for future use. At this time, the weight% of the seed crystals in the seed crystal storage slurry is 0.1% by weight.

Next, the seed crystal attachment step (S120) to the support is performed by the dip coating method (the method of dipping the support body in the seed crystal slurry), the spray coating method (the method of spray spraying the seed crystal slurry on the porous support), and the filtration method (the seed crystal slurry). Is preferably passed through a porous support). More preferably, vacuum filtration (a method of passing the seed crystal slurry through a vacuum through the porous support) is preferably used.

Here, the seed crystal slurry in the vacuum filtration process was prepared by diluting the seed crystal storage slurry in water again, and the weight of the seed crystal slurry may be adjusted by changing the amount of the seed crystal storage slurry added to water. It is 0.0005 to 0.005 weight%, More preferably, it is 0.0026 weight%.

In addition, the pressure of the vacuum portion in the seed crystal attachment process (S120) by vacuum filtration is preferably performed for 1 to 60 minutes at 1 to 300 torr, more preferably 20 minutes at 150 torr.

In addition, after the zeolite seed crystal is attached to the support (S120), it is preferable to dry the support and the seed crystal attached thereto. By drying the support and the seed crystals attached thereto, the adhesion state of the seed crystals can be further strengthened. It is preferable to perform drying at 70-120 degreeC temperature.

Next, the hydrothermal treatment (S150) is preferably performed for 12 to 48 hours at a temperature of 70 ~ 140 ℃. In this case, when the temperature of the hydrothermal solution 150 is less than 70 ° C. and the holding time is less than 12 hours, sufficient NaA zeolite separation membrane 200 may not be formed, and thus the resolution may be reduced. In addition, when the temperature of the hydrothermal solution 150 exceeds 140 ℃, and the retention time exceeds 48 hours, an undesired zeolite phase is formed on the surface of the NaA zeolite separator 200 or the membrane thickness becomes thick, resulting in a decrease in resolution. Can be.

NaA zeolite membrane according to the present invention can be easily produced through the above-described process. NaA zeolite membranes were prepared using conventional seed crystals having a size of 1 to 10 μm or using expensive raw materials and nanoscale seed crystals by a precisely controlled process. However, NaA zeolite membranes according to the present invention are reliably By producing nano-sized seed crystals in a simple, low-cost process and using them for the production of NaA zeolite membranes, it is possible to stably produce a uniform, defect-free NaA zeolite membrane.

Hereinafter, the NaA zeolite separator according to the present invention will be described in more detail based on Examples and Comparative Examples.

Example 1

As a hydrothermal solution raw material, as shown in FIG. 2, water glass, sodium aluminate, sodium hydroxide (NaOH) was dissolved in water to prepare an aqueous solution, and then stirred at 28 ° C for 24 hours to prepare a hydrothermal solution. Prepared. The total volume of the hydrothermal solution was 500 ml, and the moles of Al ₂ O ₃ , SiO ₂ , Na ₂ O, and H ₂ O in the hydrothermal solution were 1, 2, 4.5, and 600, respectively.

1 g of NaA zeolite powder was wet-pulverized for 24 hours at 500 cylces / min using 20 g of water and 90 g of diameter 1 mm alumina balls, centrifuged at 6000 rpm for 10 min and diluted in 200 g of water to obtain 0.1 wt% seed crystal storage slurry. Produced. 4 ml of the prepared seed crystal storage slurry was extracted and diluted in 150 g of water to prepare a 0.0026 wt% seed crystal slurry.

Next, a 0.0026% by weight seed crystal slurry was brought into contact with the outer surface of the alpha-alumina support having a length of 40 cm, an outer diameter of 8 mm, a pore diameter of 35%, and an average pore diameter of 0.1 µm, and the internal pressure was maintained at 150 torr for 20 minutes, followed by 100 ° C. It was dried for 12 hours to prepare a seed crystal attached support.

Subsequently, in a state in which 330 ml of a hydrothermal solution was put in a volume of 400 ml hydrothermal synthesizer, the substrate was attached to the seed crystals, and the hydrothermal synthesizer was sealed. To dry to prepare a NaA zeolite separator.

Comparative Example 1

The hydrothermal solution was prepared in the same manner as in Example 1, and the number of moles of Al ₂ O ₃ , SiO ₂ , Na ₂ O, and H ₂ O in the hydrothermal solution was 1, 2, 4.5, and 600, respectively.

1 g of NaA zeolite powder was dispersed in 1000 g of water by mixing with ultrasonic process to prepare 0.1 wt% seed crystal slurry, followed by extracting 160 ml.

0.1 wt% seed crystal slurry was brought into contact with the outer surface of the alpha-alumina support used in Example 1, and the internal pressure was maintained at 150 torr for 20 minutes, followed by drying at 100 ° C. for 12 hours to attach seed crystals. Prepared support was prepared.

Next, the 330 ml of the hydrothermal solution in the hydrothermal solution was placed in a volume 400 ml hydrothermal synthesizer, and the supporting body with the seed crystals was supported.The hydrothermal synthesizer was sealed and then hydrothermally treated at 100 ° C. for 24 hours, followed by washing with water at least 5 times To dry to prepare a NaA zeolite separator.

The NaA zeolite membrane prepared as described above was evaluated as follows.

[Fine structure]

The microstructures of the NaA zeolite separators according to Examples 1 and Comparative Example 1 above were evaluated by observing the fracture surface with a scanning electron microscope. The uniformity of the NaA zeolite separation layer formed according to the aspect of the fracture surface can be determined.

[Separation factor]

Separation performance of the zeolite separator according to each of Example 1 and Comparative Example 1 can be evaluated by the separation coefficient. The separation coefficient is, for example, when separating water and ethanol, the concentration of water in the mixed liquid before separation is A1 mol% and the concentration of ethanol is A2 mol%, and the concentration of water in the liquid or gas that has passed through the NaA zeolite membrane It is a value represented by (B1 / B2) / (A1 / A2) making B1 mol% and ethanol concentration B2 mol%.

The larger the separation coefficient, the better the separation performance, which means that there is no defect in the membrane.

Permeate Flow Rate

The water permeation flux of the zeolite separation membranes according to Examples 1 and Comparative Example 1 may be evaluated from the total permeation flux and the concentration of the permeate material. The permeation flow rate refers to the amount of liquid or gas permeating the NaA zeolite membrane at a unit time and a unit area. The permeation flow rate can be judged to be excellent in practicality as the permeation flow rate is large while having an excellent separation coefficient.

The characteristics of the NaA zeolite separators obtained in Example 1 and Comparative Example 1 are shown in Table 1 below. Scanning electron micrographs of the wavefronts and scanning electron micrographs of seed crystals prepared by wet vibration grinding and centrifugation were 3A, 3B, 4A, and 4B.

Figure 3a is a scanning electron micrograph of the diameter of 1 ~ 10㎛ NaA zeolite powder used in the present invention, Figure 3b is a scanning electron micrograph of seed crystals developed by wet vibration grinding and centrifugation in the present invention.

In the present invention, as shown in FIG. 3a, by 1 to 10 μm NaA zeolite powder, by wet vibration milling and centrifugation, seed crystals having a diameter of 100 to 300 nm as shown in FIG. 3b can be seen. Such seed crystals can be used to prepare a homogeneous and dense NaA zeolite separation membrane according to the present invention.

Figure 4a is a scanning electron micrograph of the wavefront of NaA zeolite membrane prepared according to the present invention, Figure 4b is a scanning electron micrograph of the wavefront of NaA zeolite membrane prepared according to the prior art.

Referring to each of the scale bars of FIGS. 4A and 4B, the separation layer of the NaA zeolite separator of the present invention obtained in Example 1 has a very uniform thickness of 7 μm (see FIG. 4A), but is obtained by Comparative Example 1 It can be seen that the separation layer of the NaA zeolite membrane is very heterogeneous with an average thickness of 5 μm (see FIG. 4B).

In addition, while no defects were observed in the separation layer of the NaA zeolite separation membrane of the present invention obtained in Example 1 (see FIG. 4A), defects between crystal grains, that is, non-zeolite, were present in the separation layer of the NaA zeolite separation membrane obtained in Comparative Example 1 It can be seen that a large amount of pores (see Fig. 4b).

Therefore, it can be seen that the separation layer of the NaA zeolite membrane according to the present invention is very homogeneous and has a dense structure. However, since it is practically difficult to measure this in a specific numerical range, the expression “homogeneous and dense” used in the present invention is inevitably used, and if the criteria should be identified, homogeneity and It shall be judged the density.

Next, Table 1 shows the separation of NaA zeolite membranes obtained in Example 1 and Comparative Example 1 at 60 ° C. for 5 wt% water-95 wt% ethanol and 1 wt% water-99 wt% ethanol mixture. It shows the result of measuring the performance.

 TABLE 1

Amount of water in the water-alcohol mixture
(weight%) Separation temperature
(℃) Water / Ethanol Separation Coefficient Total penetration flow rate
(kg / m ² hr) Example 1 5 60 52,606 0.06 One 60 49,000 0.04 Comparative Example 1 5 60 110 1.2 One 60 50 1.0

The NaA zeolite membrane obtained in Example 1 exhibited a very good separation coefficient of 52,606 with respect to the 5 wt% water-95 wt% ethanol mixture, whereas the NaA zeolite separator obtained in Comparative Example 1 was 5 wt% water-95 wt%. A low separation coefficient of 110 is shown for the% ethanol mixture.

This proves that there are no defects such as non-zeolitic pores in the separation layer of the NaA zeolite membrane obtained by the present invention, and the scanning electron micrograph of FIG. 4A clearly shows the fact.

In Examples NaA zeolite separation membrane of the present invention obtained in 1 NaA zeolite membrane is very large water permeation to 1.2kg / m ² hr obtained in the other hand, shows a very low water permeation flow rate of 0.06kg / m ² hr, Comparative Example 1 Indicates the flow rate.

The high permeation flux of the NaA zeolite membrane obtained in Comparative Example 1 is shown by the non-zeolite pores, which can be clearly seen in the scanning electron micrograph of FIG. 4B.

Here, the non-zeolitic pores, that is, the defect-free NaA zeolite membranes are capable of the complete separation of water / alcohol, so that the degradation coefficient of separation may occur when the weight% of water in the water-alcohol mixture is reduced to 5% by weight or less. Does not occur. That is, the NaA zeolite membrane of the present invention was able to obtain a 49,000 separation coefficient even with respect to a mixed solution in which the weight% of water was 1% by weight.

Therefore, when the NaA zeolite membrane of the present invention is applied to a water / alcohol separation process, an energy-intensive heat exchanger mounted to prevent alcohol leakage in the water / alcohol separation process equipped with a conventional NaA zeolite membrane is effectively mounted. It is possible to drive. In addition, since the NaA zeolite membrane of the present invention is relatively free from defects such as non-zeolite pores, it may be effective when applied to a membrane reaction process requiring gas separation or gas permeation.

Therefore, the method for producing NaA zeolite separator according to the present invention can provide a process for preparing a zeolite separator in which the separation layer is uniform and free from defects.

Although the above has been described with reference to one embodiment of the present invention, various changes and modifications can be made at the level of those skilled in the art. Such changes and modifications may belong to the present invention without departing from the scope of the present invention. Therefore, the scope of the present invention will be determined by the claims described below.

1 is a flow chart illustrating a method for preparing a NaA zeolite membrane according to the prior art.

Figure 2 is a flow chart illustrating a method for producing a NaA zeolite separator according to the present invention.

Figure 3a is a scanning electron micrograph of the diameter of 1 ~ 10㎛ NaA zeolite powder used in the present invention.

Figure 3b is a scanning electron micrograph of seed crystals developed by wet vibration grinding and centrifugation in the present invention.

Figure 4a is a scanning electron micrograph of the wavefront of NaA zeolite membrane prepared according to the present invention.

Figure 4b is a scanning electron micrograph of the wavefront of NaA zeolite membrane prepared according to the prior art.

Claims (17)

Dissolving alumina-based raw materials, silica-based raw materials, and sodium hydroxide in water to prepare an aqueous solution; Preparing a hydrothermal solution by mixing the aqueous solution; Wet vibrating the NaA zeolite powder and centrifuging to prepare a seed slurry; Passing the seed crystal slurry through the support by vacuum filtration to attach the seed crystal to the support surface; And And inserting the hydrothermal solution into a hydrothermal reactor to support a support on which the seed crystals are attached, and hydrothermal treatment to grow a NaA zeolite layer on the surface of the support. The method of claim 1, The alumina-based raw material is a sodium aluminate (Sodium Aluminate), aluminum hydroxide (Aluminium Hydroxide), colloidal alumina, alumina (Alumina) powder, aluminum alkoxide manufacturing method of NaA zeolite separation membrane, characterized in that at least one state. The method of claim 1, The silica-based raw material is a water glass (Sodium silicate), sodium silicate (Sodium Silicate), silica (Silica) powder, colloidal silica, silicon alkoxide, characterized in that the NaA zeolite separator manufacturing method. The method of claim 1, The addition amount of a silica-based raw material is a NaA zeolite separator manufacturing method, characterized in that the molar amount converted into silica (SiO ₂ ) is 1 to 3 times the molar amount converted from the alumina raw material to alumina (Al ₂ O ₃ ). The method of claim 1, Molar amount of the amount of addition of sodium (Sodium Hydroxide) a sodium (Na ₂ O) of sodium (Na ₂ O) oxide contained in the molar amount and the alumina-based material and a silica-containing material in terms of oxidizing the hydroxide in the sodium (Sodium Hydroxide) hydroxide The sum of the NaA zeolite membrane production method, characterized in that 2 to 6 times the molar amount of the alumina-based raw material converted to alumina (Al ₂ O ₃ ). The method of claim 1, The molar amount of water (H ₂ O) in the aqueous solution is a NaA zeolite separation membrane manufacturing method, characterized in that 400 to 800 times the molar amount of the alumina-based raw material converted to alumina (Al ₂ O ₃ ). The method of claim 1, The method of preparing a hydrothermal solution by mixing the aqueous solution may include preparing the NaA zeolite membrane by mixing the aqueous solution at a temperature of 20 to 80 ° C. for 30 minutes to 48 hours. The method of claim 1, The NaA zeolite powder is a NaA zeolite separator, characterized in that the NaA zeolite powder having a diameter of 1 ~ 10㎛. The method of claim 1, The wet vibration milling method of manufacturing a NaA zeolite membrane, characterized in that performed for 1 to 48 hours at a rate of 200 ~ 900cycles / min using a ceramic ball. The method of claim 1, The centrifugation is NaA zeolite membrane production method, characterized in that performed for 1 to 60 minutes at a speed of 1,000 ~ 15,000rpm. The method of claim 1, The seed crystals are NaA zeolite membrane production method characterized in that the diameter of 100 ~ 300nm. The method of claim 1, The seed crystal slurry is NaA zeolite membrane production method, characterized in that the seed crystals are added 0.0005 to 0.005% by weight in water. The method of claim 1, The vacuum filtration method is NaA zeolite membrane production method characterized in that performed for 1 to 60 minutes at a pressure of 1 ~ 300torr. The method of claim 1, The support is a method of producing a NaA zeolite membrane, characterized in that the porous ceramic or porous metal having a pore diameter of 0.1 ~ 1㎛. The method of claim 1, The hydrothermal treatment is NaA zeolite membrane production method characterized in that performed for 12 to 48 hours at a temperature of 70 ~ 140 ℃. The method of claim 1, The NaA zeolite layer has a thickness of 1 ~ 20 ㎛ and uniformly and densely formed method of manufacturing a NaA zeolite membrane. A zeolite separation membrane prepared by any one of claims 1 to 16.

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