KR101595741B1 - Preparing method of amin-grafting ZSM-5 zeolite for adsorption of carbon dioxide - Google Patents

Abstract

The present invention relates to a process for producing an amine-modified ZSM-5 zeolite for adsorbing carbon dioxide. According to various embodiments of the present invention, there is provided an amine modified ZSM-5 zeolite for carbon dioxide adsorption which has excellent BET surface area and total pore volume, which is never achieved by the conventional method of producing ZSM-5 zeolite, 5 zeolite. In particular, it has been confirmed that, in the case of using TEA as a structure inducing material or a method of using TPA as a structure inducing material, which has been carried out for preparing ZSM-5 zeolite in the past, The crystallization time can be reduced by 50% or more, so that there is no burden on the process for long-time reaction in the production of the conventional zeolite, so that it can be usefully used as a production method of ZSM-5 zeolite for adsorbing carbon dioxide.

Description

[0001] The present invention relates to an amine-modified ZSM-5 zeolite for adsorbing carbon dioxide,

The present invention relates to a process for producing an amine-modified ZSM-5 zeolite for adsorbing carbon dioxide.

In general, studies are being actively carried out to prevent the release of carbon dioxide, one of the greenhouse gases that have a major impact on global warming, into the atmosphere. The wet method, the dry method, and the membrane separation method are typical methods. The wet absorption method, which is a leading technology, has many problems in the commercial process, but the problem is that the apparatus is corroded and the operation cost is high due to the use of a lot of energy. As a substitute technology to solve this problem, the dry method has recently been attracting attention.

Materials that have been studied as adsorbents for the dry process include zeolite, activated carbon, alumina, metal organic frameworks (MOF), and silica. These adsorbents have a large surface area and pore structure as a porous material and physically adsorb carbon dioxide. These adsorbents can easily separate carbon dioxide adsorbed by low desorption heat, but they have a disadvantage of low low-temperature adsorption amount. Therefore, in order to improve the performance of the low-temperature adsorbent, an amine material may be impregnated.

Among the materials used as dry adsorbents, zeolite has attracted much attention as an adsorbent because of its high specific surface area and excellent thermal and mechanical stability. In the case of using zeolite as an adsorbent, the adsorption of carbon dioxide is considerably influenced by the pore structure of the zeolite.

Among the zeolites, ZSM-5 zeolite forms a three-dimensional pore consisting of a 10-tetrahedron ring, the size of which is intermediate between zeolite A, X and zeolite Y. In addition, it is a kind of pentasil zeolite which is a shape selective catalyst exhibiting unique adsorption and diffusion characteristics. It has a high SiO ₂ / Al ₂ O ₃ ratio, generally has excellent thermal stability, is hydrophobic and has a large Lewis acid point The Briststed acid point is small. In particular, it is known that gasoline oil having a high octane number directly from methanol can be directly obtained by the MTG process and is excellent in selectivity to gasoline oil. The ZSM-5 zeolite having the above characteristics is first developed It has been commercialized and used as a catalyst for petrochemicals.

Interest in industrial manufacturing aspects of ZSM-5 zeolites is focused on homogeneously synthesizing ZSM-5 zeolites with better properties in a more environmentally friendly and inexpensive way.

The ZSM-5 zeolite is prepared by hydrothermal synthesis. The composition of the ZSM-5 zeolite is slightly different from that of the zeolite in terms of method and composition. Generally, the composition of the reaction substrate in the synthesis of zeolite zeolite is aNa ₂ O ㅇ bAl ₂ O ₃ c cSiO _2? DH ₂ O? E (TPA) ₂ O (a / c: 0.02-0.43 c / b: 30?).

ZSM-5, a crystalline zeolite, was synthesized by using a template, which is an organic compound involved in crystal structure formation, in the preparation of ZSM-5 zeolite. The environmental hazards such as pollution, and the economical efficiency in using the organic template which is relatively expensive.

Thus, according to KR-10-2006-0076874, a seed crystal aligning agent, a silica sol solution and an aluminum oxide, which were introduced for kneading and molding, were mixed with ZSM-5 zeolite prepared by a method which does not use an organic template and tetrapropylammonium (TPA) and water vapor to obtain ZSM-5 zeolite. In this case, the step of mixing the aluminum oxide and the silica sol solution, aging for 12-240 hours, and performing the crystallization for 48-240 hours are included, which takes a very long time in aging and crystallization There is a problem.

As another method for producing ZSM-5 zeolite, CN 103521257 discloses a method for producing ZSM-5 zeolite using an organic amine compound such as ethylamine, diethylamine, triethylamine, propylamine or the like as a template agent, This is 60 hours, which takes a lot of processing time.

In another method for producing ZSM-5 zeolite, KR10-2004-0073712 discloses a method for preparing zeolite by adding aqueous sodium aluminate to a composition comprising a silica source in which water and an aqueous solution of sodium hydroxide are added to a porous silica support to activate the interior of the pore, The zeolite ZSM-5 zeolite is produced by the process of the present invention. However, this process also requires a long process time of about 72 hours.

The object of the present invention is to provide a process for preparing an amine-modified ZSM-5 zeolite for carbon dioxide adsorption which is improved in durability while solving the problem of a process requiring a long reaction time in the production of ZSM-5 zeolite.

(TEA) compound and a tetrapropylammonium (TPA) compound are added to a silica solution and stirred, and then an aqueous solution of an aluminum composition is added thereto. Performing hydrothermal synthesis at a temperature for 10-15 hours to obtain ZSM-5 zeolite crystals; And (2) adding the ZSM-5 zeolite crystals obtained in the step (1) to an amine modifier followed by ultrasonic treatment, to prepare an amine-modified ZSM-5 zeolite for carbon dioxide adsorption.

According to various embodiments of the present invention, there is provided an amine modified ZSM-5 zeolite for carbon dioxide adsorption which has excellent BET surface area and total pore volume, which is never achieved by the conventional method of producing ZSM-5 zeolite, 5 zeolite. In particular, it has been confirmed that, in the case of using TEA as a structure inducing material or a method of using TPA as a structure inducing material, which has been carried out for preparing ZSM-5 zeolite in the past, The crystallization time can be reduced by 50% or more, so that there is no burden on the process for long-time reaction in the production of the conventional zeolite, so that it can be usefully used as a production method of ZSM-5 zeolite for adsorbing carbon dioxide.

Hereinafter, various aspects and various embodiments of the present invention will be described in more detail.

According to one aspect of the present invention, there is provided a process for producing an amine-modified ZSM (carbon monoxide) for carbon dioxide adsorption, which comprises adding a tetraethylammonium (TEA) compound and a tetrapropylammonium -5 zeolite is disclosed.

Preferably, (1) a tetraethylammonium (TEA) compound and a tetrapropylammonium (TPA) compound are added to a silica solution and stirred, then an aqueous solution of an aluminum composition is added, Followed by hydrothermal synthesis to obtain ZSM-5 zeolite crystals; And (2) at least one amine modifier selected from the group consisting of polyethyl imine (PEI), ethylenediamine (EDA), diethylenetriamine (DETA), tetraethylenepentamine (TEPA), and pentaethylenehexamine A step of adding the ZSM-5 zeolite crystals obtained in the step (1) and then subjecting the zeolite crystals to an ultrasonic treatment, thereby producing an amine-modified ZSM-5 zeolite for adsorbing carbon dioxide.

In one embodiment of the present invention, the tetraethylammonium compound and the tetrapropylammonium compound are added at a ratio of 1: 0.5-5 by weight.

In another embodiment of the present invention, the alumina material and silica are added in a weight ratio of 1: 12-18.

In another embodiment of the present invention, in the production of the ZSM-5 zeolite crystals of the step (1), after the hydrothermal synthesis, the reaction product is filtered and dried at a temperature of 100-150 ° C for 10-15 hours And further comprising:

Specifically, the above step (1) is carried out to produce ZSM-5 zeolite having improved specific surface area and pore characteristics.

In the step (1), the silica solution can be prepared by reacting an aqueous solution of silicon and an aqueous solution of NaOH together. The aqueous solution of silicon is a solution in which silicon is dissolved in distilled water and is in a colloidal form, Silicon materials include silicon dioxide (SiO ₂ ), tetraethylorthosilicate (TEOS), sodium silicate (Na ₂ SiO ₃ ), and the like.

Also, the TEA compound and the TPA compound are structure-inducing materials used for forming pores in the zeolite. Among the methods that have been performed to prepare the conventional ZSM-5 zeolite by using the TEA compound and the TPA compound together, only the TEA compound The reaction can be carried out for a short time (10-12 hours), unlike the case where it is used as an induction material (crystallization is performed for 72 hours or more) and the case where only TPA compound is used as a structure inducing material (crystallization is performed for 60 hours or more) There is no burden on the process of performing the reaction for a long time.

In addition, when the TEA compound and the TPA compound were used together, it was confirmed that the yield was increased by 10-15% or more as compared with the case of using the TEA compound or the TPA compound, respectively.

On the other hand, the tetraethylammonium compound and the tetrapropylammonium compound have different specific surface area, total pore volume, and crystallization speed depending on the addition method. However, the addition of the tetraethylammonium compound and the tetrapropylammonium compound simultaneously increases the micropore formation rate and crystallization rate, Can be achieved.

If the tetraethylammonium compound is added first and then the tetrapropylammonium compound is added later, or if the tetrapropylammonium compound is added first and then tetraethylammonium is added, the reaction time will not be shortened, There may be a problem that the specific surface area is decreased, and the durability is deteriorated, so that the performance deterioration and the process life can be reduced.

Furthermore, the TEA compound and the TPA compound are preferably added in a weight ratio of 1: 0.5-5. When the weight ratio of the TEA compound and the TPA compound is less than the lower limit, the total pore volume is lowered If it is higher than the upper limit value, side reactions may occur and yield may be lowered.

In the step (1), the step of hydrothermally synthesizing ZSM-5 zeolite crystals may be followed by filtration of the reaction product and drying at a temperature of 100-150 ° C for 10-15 hours.

In the drying process, if the heat treatment is performed at a high temperature, the moisture inside the pores may expand and the pores may be broken, and the durability may be lowered due to sudden water evaporation. Therefore, the drying is performed at a temperature of 100-150 ° C for 10-15 hours It is preferable to remove moisture remaining in the pores.

The step (2) is carried out to modify the amine to increase the carbon dioxide adsorption rate of the ZSM-5 zeolite.

When zeolite is used as an adsorbent, when the amount of adsorbed water contained in the gas is increased, the zeolite becomes acidic and becomes unstable. When the zeolite is modified with amine, the adsorption of moisture can be suppressed The carbon dioxide adsorption rate can be increased.

On the other hand, when the ultrasonic wave is used in the step (2), there is an advantage that a catalyst is not needed for modifying the surface of the zeolite. If the ultrasonic wave is treated in a range exceeding 25-35 minutes, the problem that the bonding of the amine modifier and zeolite is deteriorated Can be.

According to one embodiment of the present invention, the amine modifier in step (2) is not particularly limited as long as it is a material capable of modifying the zeolite surface and capable of introducing an amine group into the zeolite surface. Preferably, the amine modifier is polyethylimine (PEI) At least one selected from ethylene diamine (EDA), diethylene triamine (DETA), tetraethylene pentaamine (TEPA) and pentaethylene hexaamine (PEHA) is used in a C ₁ -C ₆ linear or branched alcohol And more preferably polyethyl imine can be diluted in methanol.

In another embodiment of the present invention, the ZSM-5 zeolite crystals of step (2) and the amine modifier are added in a weight ratio of 1: 0.3-0.4.

According to an embodiment of the present invention, when the weight ratio of the ZSM-5 zeolite crystals and the amine modifier is out of the above range, when the ZSM-5 zeolite is below the lower limit value, the efficiency of introducing an amine group on the ZSM-5 zeolite surface is low, If the upper limit of the above range is exceeded, a side reaction may occur more frequently and the yield of zeolite modified with amine may be lowered, so that the carbon dioxide adsorption performance may be decreased.

In another embodiment of the present invention, the ZSM-5 zeolite crystal has a sodium ion as a cation, and the composition of the ZSM-5 zeolite crystal is Na ₂ O: SiO ₂ : Al ₂ O ₃ = 10-18: -150: 3-15, wherein the amine-modified ZSM-5 zeolite has a specific surface area of 290-300 m 2 / g and a pore volume of 0.2-0.3 cm 3 / g; And the pore diameter is 1-50 nm.

The amine-modified ZSM-5 zeolite has an adsorption amount of carbon dioxide of 2.0-2.5 mmol / g.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope and content of the present invention can not be construed to be limited or limited by the following Examples. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the present invention as set forth in the following claims. It is natural that it belongs to the claims.

Example 1

(1) Step 1: Preparation of ZSM-5 zeolite

1.89 g of NaAlO ₃ was added to 61.29 g of distilled water and mixed for 3 hours to prepare an alumina solution. 80 g of silica colloidal solution (24 g of silica) and 32.58 g of 10 wt% aqueous NaOH solution were added to 61.29 g of distilled water, To prepare a silica solution.

0.32 g of tetrapropylammonium bromide (TPA-Br) and 0.25 g of tetraethylammonium bromide (TEA-Br) (TPA-Br / TEA-Br weight ratio = about 1.3: 1) were simultaneously added to the silica solution for 3 hours The alumina solution was added and stirred for 1 hour, followed by hydrothermal synthesis reaction at 190 ° C for 12 hours.

After completion of the reaction, the mixture was filtered, and then dried at 120 DEG C for 12 hours to obtain ZSM-5 zeolite crystals.

ZSM-5 zeolite obtained in the above has a sodium ion as a cation, the zeolite during manufacture, the molar ratio of the compound is _{Na 2 O: SiO 2: TEA} + TPA: Al 2 O 3: H 2 O = 13: 100: 3: 10: 2900.

(2) Step 2: Preparation of amine-modified ZSM-5 zeolite

0.7 g of the adsorbent crystal was added to a solution of 0.25 g of polyethyleneimine (PEI) dissolved in 10 ml of methanol, and sonicated for 30 minutes to dry the amine-impregnated adsorbent at 60 ° C for 12 hours to obtain a carbon dioxide adsorbent.

Example 2

A carbon dioxide adsorbent was obtained in the same manner as in Example 1 except that 0.3 g of PEI was used instead of 0.25 g of PEI.

Example 3

A carbon dioxide adsorbent was obtained in the same manner as in Example 1 except that TPA and TEA were added at a weight ratio of 3: 1 instead of 1.3: 1 at a weight ratio of TPA and TEA.

Example 4

A carbon dioxide adsorbent was obtained in the same manner as in Example 1 except that TPA and TEA were added at a weight ratio of 6: 1 instead of 1.3: 1 at a weight ratio.

Example 5

A carbon dioxide adsorbent was obtained in the same manner as in Example 1 except that TPA and TEA were added at a weight ratio of 0.3: 1 instead of 1.3: 1 at a weight ratio.

Comparative Example 1

Carbon dioxide adsorbent was obtained in the same manner as in Example 1 except that TPA-Br was used in an amount corresponding to the amount of TEA-Br instead of using TEA-Br.

At this time, the hydrothermal synthesis reaction time was 48 hours.

Comparative Example 2

Carbon dioxide adsorbent was obtained in the same manner as in Example 1 except that TPA-Br was not used but TEA-Br was used as much as the content.

At this time, the hydrothermal synthesis reaction time was 52 hours.

Experimental Example 1

The specific surface area and the total pore volume of the zeolite adsorbent prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were measured, and the results are shown in Table 1 below. Micromeritics ASAP 2020 was used as the analyzing instrument. Before the measurement, the adsorbent samples of Examples 1 to 4 and Comparative Examples 1 and 2 were pretreated at 400 ° C. for 4 hours under a vacuum condition, and then the adsorbent samples were measured at -195.6 ° C. Nitrogen adsorption / desorption was performed.

The surface area was calculated using the Brunauer-Emmett-Teller (BET) method and the pore volume was calculated using the Barrett-Joyner-Halenda (BJH) model.

division ZSM-5 types BET surface area
[m ² / g] Total volume
[cm ³ / g] Example 1 TEA + TPA 294.6463 0.2391 Example 2 TEA + TPA 293.7256 0.2387 Example 3 TEA + TPA 290.5103 0.2179 Example 4 TEA + TPA 293.4225 0.2247 Comparative Example 1 TEA 270.9243 0.1807 Comparative Example 2 TPA 282.1550 0.2148

As shown in Table 1, in the case of the zeolite adsorbents prepared in Examples 1 to 4 according to the present invention, zeolite prepared by using only TEA as a porogen in Comparative Example 1 or TPA alone in Comparative Example 2 It was confirmed that BET surface area and total pore volume were superior to the prepared zeolite.

Experimental Example 2

Table 2 shows the results of comparing the adsorption amounts of carbon dioxide according to the PEI contents of the structure-inducing materials of the zeolite adsorbents prepared in Examples 1 to 4 and Comparative Examples 1 and 2.

The amount of carbon dioxide adsorption was determined by thermogravimetric analysis.

First, the ZSM-5 adsorbent samples prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were pretreated under a nitrogen atmosphere at 100 ° C. for 70 minutes, cooled to 40 ° C., and then carbon dioxide gas The amount of adsorbed carbon dioxide on the zeolite was measured by confirming the weight change of the zeolite adsorbent according to the present invention.

division PEI contents
(PEI loading) Quantity of CO ₂ adsorption (mmol / g) 0 g 0.25 g
(33.3%) 0.3 g
(37.5%) Example 1 TEA + TPA 1.3732 2.4881 2.2292 Example 2 TEA + TPA 1.3852 2.4921 2.2382 Example 3 TEA + TPA 1.2965 2.2854 2.1621 Example 4 TEA + TPA 1.3511 2.4110 2.1948 Comparative Example 1 TEA 1.2640 2.2554 2.1380 Comparative Example 2 TPA 1.3288 2.3554 2.1568

As shown in Table 2, in the case of the zeolite adsorbents prepared in Examples 1 to 4 according to the present invention, only the TEA was used in Comparative Example 1, or the adsorption of carbon dioxide on the zeolite adsorbent prepared using TPA alone in Comparative Example 2 Of the total.

Particularly, the result of showing a better carbon dioxide adsorption rate in Example 1-4 in which the hydrothermal synthesis time is shorter than that of Comparative Examples 1 and 2 in which hydrothermal synthesis time is 48 hours and 52 hours, respectively, is much shorter (10-12 hours) .

As described above, when ZSM-5 zeolite is prepared by the process according to the present invention, the BET surface area and the BET surface area of the ZSM-5 zeolite prepared using TEA or TPA, which are conventionally used as a structure inducing material, The zeolite can be advantageously used as a production method of ZSM-5 zeolite because it has excellent total pore volume, excellent carbon dioxide adsorption amount, and can reduce the crystallization time which is the most problematic in the conventional ZSM-5 zeolite production by more than 50%.

Claims (9)

delete (1) A triethylamine compound and a tripropylamine compound are simultaneously added to a silica solution at a weight ratio of 1: 0.5-5 and stirred, and then an aqueous alumina solution is added. Followed by filtration and drying at a temperature of 100-150 DEG C for 10-15 hours to obtain ZSM-5 zeolite crystals; And
(2) The ZSM-5 zeolite crystals obtained in the above step (1) are added to at least one amine modifier selected from polyethylimine, ethylenediamine, diethylenetriamine, tetraethylenepentamine and pentaethylenehexamine, And ultrasonic treatment,
Wherein the ZSM-5 zeolite crystals and the amine modifier of step (2) are added in a weight ratio of 1: 0.3-0.4.
delete 3. The method of claim 2, wherein the alumina material and silica are added in a weight ratio of 1: 12-18 by weight to the amine-modified ZSM-5 zeolite for carbon dioxide adsorption.
delete delete The zeolite zeolite according to claim 2, wherein the ZSM-5 zeolite crystal has a sodium ion as a cation,
Wherein the composition of the ZSM-5 zeolite crystals is a molar ratio of Na ₂ O: SiO ₂ : Al ₂ O ₃ = 10-18: 30-150: 3-15. Way.
The zeolite according to claim 2, wherein the amine-modified ZSM-5 zeolite has a specific surface area of 290-300 m 2 / g,
The pore volume is 0.2-0.3 cm < 3 > / g;
Characterized in that the pore diameter is 1-50 nm. ≪ RTI ID = 0.0 > 15. < / RTI >
The method of claim 2, wherein the amine-modified ZSM-5 zeolite has an adsorption amount of carbon dioxide of 2.0-2.5 mmol / g.