KR20150125183A - Synthetic Method of Kapok-Zeolite hybrid composites - Google Patents

Abstract

The present invention relates to a method for synthesizing a kapok-zeolite composite, which comprises the steps of: (step 1) treating kapok with a surfactant; (step 2) producing a mixture by mixing silica sol, sodium aluminate, sodium hydroxide, tetrapropyl ammonium bromide (TPABr), and water; (step 3) aging the mixture; (step 4) hydrothermally reacting the aged mixture with the treated kapok; (step 5) filtering and washing the synthesized material; and (step 6) drying the filtered and washed synthesized material. Synthesis is performed after surface properties of kapok are changed by using an anion surfactant, so a very uniform zeolite layer is formed on a surface of kapok. Compared to ZSM-5 of Zeolyst Company, heavy metal removing effects are twice excellent.

Description

Synthetic Method of Kapok-Zeolite Hybrid Composites < RTI ID = 0.0 >

More particularly, the present invention relates to a method of synthesizing kapok-zeolite hybrid composites by attaching ZSM-5 zeolite to the surface of a natural fiber Kapok as a template. Kaolin-zeolite complexes.

The zeolite was synthesized in the 1950 's and its crystal structure, molecular size and adsorption characteristics with natural products were investigated. In the 1960' s, synthetic zeolite was used as an industrial catalyst and 100 kinds were synthesized. Catalysts, adsorbents, and additives for detergents. Petrochemicals are used as catalysts in various processes such as catalytic cracking, isomerization and alkylation. Among these, Zeolite Socony Mobile Number 5 (ZSM-5) is a medium pore zeolite with a three-dimensional channel made by hydrothermal method by Argaure and Landolt in 1972. It is a crystalline aluminosilicate with MFI structure. It has a structure in which a straight channel through which pores are linearly passed and a sinusoidal channel in the form of zig-zag are connected by a three-dimensional structure, and has a sine-shaped pore and an oval- I have. Tetrapropyl ammonium bromide (TPABr) and tetrapropyl ammonium hydroxide (TPAOH) are mainly used as structural stabilizers to prevent crystal formation and phase transition after crystal formation during ZSM-5 zeolite crystal formation. These organic amine derivatives In the crystal formation process, cations such as Na ⁺ promote nucleation and TPA ⁺ forms a complex with other ions, so that they have a template function during nucleation.

In addition, Shiyun Sang et al. Synthesized ZSM-5 zeolite using BTA (n-butylamine), ETA (ethylamine), IPA (isopropylamine), EDA (ethylenediamine), ETL (ethanol) and ETL-AM (ethanolammonium).

Synthesis of ZSM-5, a high silica zeolite, is usually carried out in a high-pressure stainless steel vessel by limiting the size of the reaction, since it is usually carried out at a temperature of 140 to 210 ° C for 2 to 5 days. Most of the studies are on optimization studies on the composition, and large processes have a drawback in that they require a lot of capital to manufacture and install the high-pressure reactor.

Korean Patent Registration No. 10-0511638 (Aug. 31, 2005) discloses a process for producing ZSM-5 based zeolite. In the above-mentioned production method, in the hydrothermal synthesis of a zeolite, the porous silica support is treated with an aqueous solution of sodium hydroxide to absorb the aqueous solution of sodium aluminate into a silica source activated inside the pores of the porous silica support, To produce fine and uniform ZSM-5 crystal grains, thereby inhibiting single crystal growth of the ZSM-5 crystal grains trapped in the pores of the porous silica carrier and producing a polycrystalline ZSM-5 aggregate The present invention can remarkably improve the production yield of ZSM-5-based zeolite as well as drastically improve the filtration efficiency after the production, thereby reducing manufacturing cost and eco-friendly effect.

However, a method of synthesizing ZSM-5 zeolite by using Kapok, a natural fiber, has not been studied yet.

KR 10-0511638 B1 Aug. 31, 2005.

It is an object of the present invention to provide a method for synthesizing a kapok-zeolite composite in which Kapok-Zeolite hybrid composites can be synthesized by attaching ZSM-5 based zeolite to the surface using Kapok as a template.

In order to achieve the above object, the present invention provides the following means.

The present invention relates to a method of treating Kapok with a surfactant (step 1); (Step 2) by mixing silica sol, sodium aluminate, sodium hydroxide, Tetrapropyl ammonium bromide (TPABr) and water to form a mixture; Aging the mixture (step 3); Hydrothermal reaction of the treated kapok with the aged mixture (step 4); Filtering and washing the composite (step 5); And drying (step 6) drying the filtered and washed composite. The present invention also provides a method of synthesizing a kapok-zeolite complex.

In the step 1, the surfactant uses an anionic surfactant.

In the step 2, the Si / Al ratio may be 200. [

In step 4, the hydrothermal synthesis is carried out at a temperature of 150 to 185 DEG C at 200 rpm for 24 hours.

The hydrothermal synthesis is synthesized in an autoclave reactor.

Since the kapok-zeolite complex according to the present invention has an advantage that a uniform zeolite layer is formed on the kapok surface since an anionic surfactant is used to change the surface properties of the kapok, the heavy metal removal effect Is more than twice as good.

1 is a view showing an XRD pattern of a zeolite microtube synthesized in the present invention.
2 is a view showing a TGA of a zeolite microtube synthesized in the present invention.
Fig. 3 is a view showing FT-IR of a zeolite microtube synthesized in the present invention. Fig.
FIG. 4 is a photograph showing the zeolite produced at a reaction temperature of 150 ° C and a Si / Al ratio = 200.
FIG. 5 is a photograph showing a zeolite produced at a reaction temperature of 150 ° C. under a Si / Al ratio = 100.
FIG. 6 is a photograph showing a zeolite produced at a reaction temperature of 150 ° C. and a Si / Al ratio = 25.
7 is a photograph showing a zeolite produced at a reaction temperature of 175 ° C and a Si / Al ratio = 200.
8 is a photograph showing the zeolite produced at a reaction temperature of 175 ° C and Si / Al ratio = 100.
9 is a photograph showing the zeolite produced at a reaction temperature of 175 ° C and Si / Al ratio = 25.
10 is a photograph showing a zeolite produced at a reaction temperature of 185 ° C and a Si / Al ratio = 200.
11 is a photograph showing a zeolite produced at a reaction temperature of 185 캜 and a Si / Al ratio = 100.
12 is a photograph showing a zeolite produced at a reaction temperature of 185 ° C and a Si / Al ratio = 25.
13 is a photograph of a zeolite microtube synthesized by treatment with a cationic surfactant.
14 is a photograph of a zeolite microtube synthesized by treating with an anionic surfactant.
15 is a Schematic diagram illustrating the synthesis of kapok-zeolite.
16 is a graph showing a heavy metal adsorption rate of a kapok-zeolite complex obtained by treating with an anionic surfactant at a synthesis temperature of 150 ° C and a Si / Al ratio of 200;
17 is a graph showing the heavy metal adsorption rate of a kapok-zeolite complex prepared by treating with a cationic surfactant at a synthesis temperature of 185 ° C and a Si / Al ratio of 25;
18 is a graph showing a heavy metal adsorption rate of ZSM-5 of Zeolyst, which is distributed in the market, over time.

Hereinafter, the present invention will be described in detail.

Since ZSM-5 zeolite is hydrothermally synthesized in water, crystals grow in the water, not on the Kapok surface, as the reaction proceeds.

The present invention is characterized in that Kapok-Zeolite hybrid composites are synthesized by allowing zeolite to synthesize on the kapok surface since the surface properties of Kapok are changed by using a surfactant to synthesize zeolite.

First, the synthesis method of the kapok-zeolite complex according to the present invention will be described.

The method of synthesizing the kapok-zeolite complex of the present invention comprises:

Treating Kapok with a surfactant (step 1);

(Step 2) by mixing silica sol, sodium aluminate, sodium hydroxide, Tetrapropyl ammonium bromide (TPABr) and water to form a mixture;

Aging the mixture (step 3);

Hydrothermal reaction of the treated kapok with the aged mixture (step 4);

Filtering and washing the composite (step 5); And

Drying the filtered and washed composite (step 6);

.

In step 1, kapok refers to natural vegetable seed fiber. Since the kaolin surface property is changed by using the above surfactant, when a synthesis is carried out after treatment with an anionic surfactant (SDS), a very uniform zeolite layer can be formed on the surface of the carapace, so that an anionic surfactant is preferably used .

Step 2 is a step for preparing a mixture by mixing silica sol, sodium aluminate, sodium hydroxide, Tetrapropyl ammonium bromide (TPABr) and water.

Factors affecting the synthesis of ZSM-5 include type of silica source, Si / Al ratio, concentration of alkali solution, mixing order of reactants, crystallization temperature, crystallization time, degree of aging and stirring.

In the present invention, silica sol may be used as the silica source, and sodium aluminate may be used as the alumina source.

In the step 3, the mixture is preferably aged for at least 24 hours.

In the step 4, the treated kapok and the aged mixture are preferably hydrothermally synthesized by stirring the mixture at a temperature of 150 to 185 DEG C at 200 rpm for 24 hours.

Step 5 is a step of filtering and washing the compound.

In step 6, the filtered and washed composite is preferably dried at a temperature of 60 DEG C for 24 hours.

After the step 6, a step of calcination at a temperature of 300 to 500 ° C at 3 ° C / min may be added.

Hereinafter, the constitution and effects of the present invention will be described in more detail through examples. These embodiments are only for illustrating the present invention, and the scope of the present invention is not limited by these embodiments.

Kapok was surface-treated with a surfactant. The mixture was made by mixing silica sol, sodium aluminate, sodium hydroxide, Tetrapropyl ammonium bromide (TPABr) and water. The mixture was aged for 24 hours. The surface treated kapok and the aged mixture were subjected to hydrothermal synthesis by stirring at a temperature of 150 to 185 DEG C at 200 rpm for 24 hours. The compound was filtered and washed with water. The filtered and washed composite was dried at a temperature of 60 캜 for 24 hours to obtain a kapo-zeolite complex.

[Experimental Example 1]

In order to confirm the crystallization characteristics of the ZSM-5 zeolite synthesized in Example 1, an X-ray diffractometer was used to measure the crystallization characteristics in the range of 0 to 50 °. The results are shown in FIG. 1 . When X-rays are irradiated on zeolites, they are expressed in a dispersed form by the regular arrangement of atoms in the structure. The spacing of 2? By Bragg formula n? = 2dsin? Reflects that the zeolite component is symmetrical. Where n = integer, λ = wavelength, d = atomic spacing, and θ = diffraction angle respectively. FIG. 1 shows that the 2θ values show strong characteristic peaks at 7.9, 8.8, 23.1, and 23.9, and these results are consistent with the characteristic peaks of ZSM-5 disclosed by Arguer, Landolt et al.

[Experimental Example 2]

Fig. 2 shows the results of thermal analysis of the ZSM-5 zeolite measured at a heating rate of 10 [deg.] C / min in the range of 0 [deg.] C to 950 [deg.] C to determine the temperature at which TPABr as a template filling the channel is removed. The weight loss curve with temperature showed the removal of NH ⁺ used for water and ion exchange as a primary weight loss at around 200 ℃. The secondary weight reduction shows a weight loss at around 420 ° C and an exothermic peak, which indicates that the TPA ⁺ ion of the template TPABr is removed by the exothermic reaction.

[Experimental Example 3]

The FTIR of the ZSM-5 zeolite synthesized in Example 1 was measured and shown in FIG. The absorption band at ¹ has been found ^{- 1220㎝ -1, 1100㎝ -1, 800㎝} -1, 550㎝ -1, 450㎝ As shown in FIG. It can be seen that as the characteristic adsorption band of ZSM-5 zeolite, crystals having three-dimensional channel pores are formed. Clearly shows the ^{450㎝ -1 T (T = Si,} Al) MFI-type zeolite of D5R (Double five fing) one structure in the inner band -O tetrahedron bending vibration and 550㎝ ^-1 of at. Frequency 800㎝ ^-1, 1100㎝ ^-1, 1220㎝ ^- absorption bands at ^1, is meant to D5R the four chain structure are linked to the existing rotating shaft 2 (two-fold axis).

[Experimental Example 4]

The BET surface area, which is an important characteristic of the catalyst utilization of the zeolite, was measured. The TPA ⁺ ion filling the pores of the zeolite obtained by the synthesis was 99.6 m2 / g, which is a low specific surface area. However, after calcination, a specific surface area of 392 m 2 / g was obtained. This was due to the development of pores in the structure due to removal of TPA ⁺ ions. The high crystallinity of zeolite may also be high. The ZSM-5 value of the literature is known to be about 340 to 410 m 2 / g, which is similar to that of the zeolite microtube synthesized in Example 1.

[Experimental Example 5]

In Example 1, zeolite was prepared by varying the reaction temperature and Si / Al ratio, and the shape of the synthesized material was observed. The results are shown in FIGS. 4 to 12.

Degree Temp. (占 폚) Si / Al Ratio 4
150
200 5 100 6 25 7
175
200 8 100 9 25 10
185
200 11 100 12 25

Referring to FIGS. 4 to 12, it can be seen that the shape of the disk is 1.2 to 2 탆 in overall, and is shaped like a rectangular disk and a flat disk. As a whole, it was observed that the crystal shape was greatly changed according to the composition and temperature of the reaction mixture. As the Si / Al ratio decreased, the uniformity was lost and the shape was diversified. It is considered that when the concentration of alkali is high, the corner portions having high chemical potential during the growth process are rounded by repeating the process of dissolution and growth. It was confirmed that crystals similar to the ZSM-5 form were formed at the Ratio value of 200 and at the temperature range of 150 to 175 ° C., and crystals near to spherical shape were formed at the temperatures higher than that.

[Experimental Example 6]

In Example 1, self-assembling was induced by imparting the ionicity of a surfactant to grow on the surface of Kapok. The zeolite was grown by comparing with a cationic surfactant (CTAB) and an anionic surfactant (SDS), respectively. The results are shown in Figs. 13 and 14.

Degree Temp. (占 폚) Si / Al Ratio Kapok Per-treatment


13





150
200


CTAB




100 25
175
200 100 25
185
200 100 25 14 150 200 SDS

The composition of Table 2 was synthesized, treated with a cationic surfactant (CTAB), and then grown on Kapok. The results are shown in FIG. 13. The zeolite was not uniformly grown regardless of the zeolite synthesis composition and the zeolite form was not uniformly synthesized.

In the case of FIG. 14 treated with an anionic surfactant (SDS), it is not uniformly arranged as compared with the cationic surfactant, but is relatively well grown inside and outside the Kapok.

As shown in FIG. 15, in the case of the cationic surfactant, the TPABr used as a template in the synthesis of the zeolite extends from the outer side of the Kapok to crystallize the zeolite particles and is difficult to grow in the Kapok. On the other hand, the anionic surfactant, It can be concluded that the interactions of prominent ammonium ions have resulted in the growth of zeolite particles from the outer surface.

[Experimental Example 7]

The hydrothermal synthesis of stainless steel pressure vessel and autoclave reactor was compared at high temperature and high pressure. In the autoclave reactor, it was crystallized as a flat disc or circular form of zeolite, and crystallized zeolite was well grown on Kapok. On the other hand, when hydrothermal synthesis was carried out in a stainless steel pressure vessel, the shape of the zeolite was hard to find and the silica particles were attached to the Kapok. As a result, hydrothermal synthesis at high temperature and high pressure conditions should be carried out in order to induce zeolite synthesis and self-assembling.

[Experimental Example 8]

The degree of heavy metal adsorption of the kapok-zeolite complex synthesized in the present invention was examined. The adsorption removal rate was determined according to the following equation.

Adsorption removal rate (%) = (Ci - Cf) * 100 / Ci

(Ci = initial concentration of the sample (ppm), Cf = concentration of the sample after the adsorption reaction (ppm))

Fig. 16 shows heavy metal adsorption removal ratios of the kapok-zeolite complex prepared by treating with an anionic surfactant in Example 1 at a synthesis temperature of 150 ° C and a Si / Al ratio of 200.

FIG. 17 shows the heavy metal adsorption removal rate of the kappa-zeolite complex prepared by treating with a cationic surfactant in Example 1 and having a synthesis temperature of 185 ° C. and a Si / Al ratio of 25.

FIG. 18 shows the heavy metal adsorption removal rate of ZSM-5 from Zeolyst, which is commercially available.

16 and 17, the concentration of heavy metal elements in the heavy metal solution decreased with increasing agitation time. As a result, it can be seen that heavy metals except Pb are removed within 30 minutes. Adsorption removal rates were in the order of Cr>Cu>Zn>Ni> Pb.

Referring to FIG. 16, the adsorption rate of heavy metal was highest at 22% in the case of Zeolite synthesized by treatment with an anionic surfactant, and in FIG. 17, the adsorption rate of Zeolite synthesized by treatment with a cationic surfactant was 15%. It can be seen that Kapok is basically adsorbed into pores and zeolite developed pores even though they are not completely formed in structural or morphological form.

On the other hand, FIG. 18 shows that the heavy metals adsorption rate of ZSM-5 of Zeolyst, which is distributed in the market, is about 10% in case of Cr.

Therefore, it can be seen that the kapok-zeolite composite according to the present invention is twice or more superior to ZSM-5 of Zeolyst, which is in the market, over time to remove heavy metals.

Unlike ZSM-5 having an irregular arrangement, the kapok-zeolite composite according to the present invention is in the form of a fiber and can be interpreted as having a favorable structure for adsorption and a high specific surface area, resulting in a high removal rate.

Claims (5)

Treating Kapok with a surfactant (step 1);
(Step 2) by mixing silica sol, sodium aluminate, sodium hydroxide, Tetrapropyl ammonium bromide (TPABr) and water to form a mixture;
Aging the mixture (step 3);
Hydrothermal reaction of the treated kapok with the aged mixture (step 4);
Filtering and washing the composite (step 5); And
Drying the filtered and washed composite (step 6);
≪ / RTI >
2. The method according to claim 1, wherein, in step 1,
Wherein said surfactant is an anionic surfactant.
2. The method according to claim 1, wherein in step 2,
Synthesis method of kappa - zeolite complex having Si / Al ratio of 200.
2. The method of claim 1, wherein in step 4,
Wherein said hydrothermal synthesis is carried out at a temperature of from 150 to 185 DEG C at 200 rpm for 24 hours to synthesize a kappa-zeolite complex.
5. The method of claim 4,
The hydrothermal synthesis is a synthesis method of a kapok-zeolite complex synthesized in an autoclave reactor.

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