KR20140088985A - Method for synthesizing zeolite using fly ash - Google Patents

Method for synthesizing zeolite using fly ash Download PDF

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KR20140088985A
KR20140088985A KR1020120158371A KR20120158371A KR20140088985A KR 20140088985 A KR20140088985 A KR 20140088985A KR 1020120158371 A KR1020120158371 A KR 1020120158371A KR 20120158371 A KR20120158371 A KR 20120158371A KR 20140088985 A KR20140088985 A KR 20140088985A
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molar ratio
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이창한
박종원
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부산가톨릭대학교 산학협력단
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    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J39/00—Cation exchange; Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
    • B01J39/08—Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
    • B01J39/14—Base exchange silicates, e.g. zeolites
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    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
    • C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
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Abstract

The present invention relates to a method for synthesizing zeolite using fly ash (FA) for having high degree of crystalinity and excellent ion-exchange capacity by optimizing a ratio of SiO_2/Al_2O_3 and an alkali content as a variable of zeolite synthesis using FA, adds Na_2CO_3 to FA including SiO_2 and Al_2O_3 and is characterized by synthesizing zeolite having the characteristics of NA-A type zeolite by increasing a mole ratio of Na_2CO_3/FA in order to be 0.9 or more when a mole ratio of SiO_2/Al_2O_3 is 1.5 or more.

Description

METHOD FOR SYNTHESIZING ZEOLITE USING FLY ASH BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zeolite-

The present invention relates to a zeolite synthesis method using a fly ash, and more particularly fly ash (Fly Ash; hereinafter FA) to a zeolite synthesis parameters using the alkali content and the SiO 2 / Al 2 O 3 molar ratio optimized in excellent and high crystallinity, the The present invention relates to a zeolite synthesis method using a fly ash having an ion exchange capacity.

Rapid industrialization has increased demand for energy, and various energy sources such as coal, nuclear power, and renewable energy are being used.

Among them, coal is used as raw material for thermal power generation worldwide due to abundant reserves, stability of supply source and low price, and it discharges a large amount of incineration ash, including fly ash during the combustion process. The amount of coal fly ash in the world is estimated to be about 480 million tons. Domestic coal fly ash production is gradually increasing from 2 million tons in 1989, 5.84 million tons in 2006, and 7.3 million tons in 2010.

Coal fly ash is composed of mullite, quartz, hematite, which are mainly composed of SiO 2 , Al 2 O 3 and Fe 2 O 3 . Because these components have pozzolanic activity, coal fly ash is mostly recycled as an admixture for concrete and concrete. Recycling methods of converting zeolite into high value-added materials by using a large amount of silica and alumina contained in the coal fly ash material are attracting attention.

In the conventional zeolite synthesis method using fly ash, it has been reported that the concentration of Si 4 + and Al 3 + in the solution influences the zeolite crystal structure such as Na-A and Na-X type using hydrothermal synthesis using high concentration NaOH Tanaka et al., 2009). In addition, the optimal synthesis conditions were suggested by evaluating the efficiency of zeolite synthesis depending on the crystallinity and crystal structure of Na-P type in the hydrothermal synthesis according to the type of alkali added using high concentration NaOH, KOH and Na 2 CO 3 (Murayama et al. , 2002). By using a zeolite prepared from coal fly ash compared to Co 2+, Cr 3 +, Cu 2 +, Ni 2 + , and Zn + 2 selective adsorption and recovery of the performance of the ion were evaluated for efficacy as metal ion adsorbent (Hui et al., 2005). By using a synthetic zeolite compare Co 2 +, Cu 2 +, and Ni 2+ ion adsorption properties of the Cu 2 + ions having a high selectivity, heavy metals in the natural zeolite (Pb 2 +, Cd 2 +, Cu 2 + , Zn 2 + , Ni 2 + ) selectivity silver ion is an important factor (Lee, 1999, Mishra et al., 2006). Natural and synthetic zeolites have been used as adsorbents and catalysts for various applications because of their ion exchange capacity, molecular sieving effect, selective adsorption power, dehydration and reabsorption properties (Oh, YH, 1999) . In order to increase the added value of coal fly ash discharged from thermal power plants, researches on the synthesis of zeolite from fly ash have been actively carried out (Inada et al., 2005; Wang et al., 2008; Ye et al., 2008; al., 2008).

However, there is no clear standard for the structure, crystallinity, and ion exchange capacity of synthetic zeolite depending on the alkali content, SiO 2 / Al 2 O 3 mole ratio of the mixed material as synthesis parameters in the synthesis of zeolite using fly ash, It is true that it falls.

The present invention has been made in order to solve the above problems, and its object is to optimize the alkali content and the SiO 2 / Al 2 O 3 molar ratio as synthesis variables in the synthesis of zeolite using fly ash, And a method for synthesizing zeolite using fly ash.

The optimum alkali content and SiO 2 / Al 2 O 3 It is an object of the present invention to provide a zeolite synthesis method using fly ash which improves the exchangeability of Cu 2 + and Zn 2 + ions by using a zeolite having a high crystallinity synthesized at a molar ratio.

According to an aspect of the present invention, there is provided a zeolite synthesis method of adding Na 2 CO 3 to a fly ash containing SiO 2 and Al 2 O 3 , wherein when the molar ratio of SiO 2 / Al 2 O 3 is 1.5 or more, Na 2 CO 3 / FA molar ratio is increased to 0.9 or more to synthesize a zeolite having the characteristics of NA-A type zeolite.

Preferably, when the molar ratio of SiO 2 / Al 2 O 3 is 1.5, the molar ratio of Na 2 CO 3 / FA is adjusted to 1.8 to 2.4.

Preferably, when the molar ratio of SiO 2 / Al 2 O 3 is 2.0, the molar ratio of Na 2 CO 3 / FA is increased to 0.6 or more.

Preferably, the molar ratio of Na 2 CO 3 / FA is adjusted to 1.2 to 1.8.

Preferably, when the molar ratio of SiO 2 / Al 2 O 3 is 2.5, the molar ratio of Na 2 CO 3 / FA is increased to 1.2 or more.

Preferably, when the molar ratio of SiO 2 / Al 2 O 3 is 3.0, the molar ratio of Na 2 CO 3 / FA is increased to 1.2 or more.

Preferably, the molar ratio of Na 2 CO 3 / FA is adjusted to 1.8 to 2.4.

According to another aspect of the present invention, there is provided a zeolite synthesis method of adding Na 2 CO 3 to a fly ash containing SiO 2 and Al 2 O 3 , wherein when the molar ratio of Na 2 CO 3 / FA is 0.6 or more, 2 / Al 2 O 3 is increased to 1.5 or more to synthesize a zeolite having characteristics of NA-A type zeolite.

Preferably, when the molar ratio of Na 2 CO 3 / FA is 0.6, the molar ratio of SiO 2 / Al 2 O 3 is increased to 2.0 or more.

Preferably, when the molar ratio of Na 2 CO 3 / FA is 1.2, the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 1.5 to 4.0.

Preferably, the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 2.0.

Preferably, when the molar ratio of Na 2 CO 3 / FA is 1.8, the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 1.5 to 4.0.

Preferably, the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 2.0.

Preferably, when the molar ratio of Na 2 CO 3 / FA is 2.4, the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 1.5 to 4.0.

According to another aspect of the present invention, there is provided a zeolite synthesis method of adding Na 2 CO 3 to a flyash comprising SiO 2 and Al 2 O 3 , wherein the molar ratio of Na 2 CO 3 / FA is increased, Characterized by synthesizing a zeolite having characteristics of a high NA-A type zeolite.

Preferably, the molar ratio of Na 2 CO 3 / FA is adjusted to 1.2 to 2.4.

Preferably, when the molar ratio of Na 2 CO 3 / FA is 1.8, the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 1.5 to 4.0, wherein the molar ratio of SiO 2 / Al 2 O 3 is high And the crystallinity is increased.

Preferably, when the molar ratio of Na 2 CO 3 / FA is 2.4, the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 2.0 to 4.0, wherein the molar ratio of SiO 2 / Al 2 O 3 is high And the crystallinity is increased.

According to another aspect of the present invention, there is provided a zeolite synthesis method of adding Na 2 CO 3 to a fly ash containing SiO 2 and Al 2 O 3 , wherein the molar ratio of Na 2 CO 3 / FA is increased to perform cation exchange Characterized in that a zeolite having the characteristics of a NA-A type zeolite having a high capability is synthesized.

Preferably, the molar ratio of Na 2 CO 3 / FA is adjusted to 1.2 to 2.4.

Preferably, the SiO 2 / Al 2 O 3 molar ratio is in the range of 1.5 to 4.0 and has the ability to exchange Cu 2 + ions.

Preferably, the SiO 2 / Al 2 O 3 molar ratio is in the range of 1.5 to 4.0 and has an ion exchange capacity of Zn 2 + .

According to the present invention, the alkali content and the SiO 2 / Al 2 O 3 ratio of the mixed material are optimized as synthesis parameters in the synthesis of zeolite using fly ash, thereby improving the structure and crystallinity of the synthetic zeolite.

The optimum alkali content and SiO 2 / Al 2 O 3 It also has the effect of improving the exchange capacity of Cu 2 + and Zn 2 + ions by using a zeolite having a high crystallinity synthesized in the ratio.

Figure 1 is a SEM image of FA and Z-WK used in zeolite synthesis.
2 is a view for explaining a process of synthesizing zeolite using fly ash.
FIGS. 3 to 7 show XRD patterns of the synthesized zeolite according to the Na 2 CO 3 / FA molar ratio, respectively. FIG.
8 to 11 are diagrams showing XRD patterns of synthetic zeolite according to the molar ratio of SiO 2 / Al 2 O 3 .
12 is Na 2 CO 3 / FA molar ratio of SiO 2 / Al 2 O 3 as 0.6 days Lt; RTI ID = 0.0 > SEM < / RTI >
13 is Na 2 CO 3 / FA molar ratio of SiO 2 / Al 2 O 3 as 1.2 days Lt; RTI ID = 0.0 > SEM < / RTI >
14 is Na 2 CO 3 / FA molar ratio of SiO 2 / Al 2 O 3 as 1.8 days Lt; RTI ID = 0.0 > SEM < / RTI >
15 is Na 2 CO 3 / FA molar ratio of SiO 2 / Al 2 O 3 as 2.4 days Lt; RTI ID = 0.0 > SEM < / RTI >
16 is a diagram showing the degree of crystallization according to the molar ratio of Na 2 CO 3 / FA.
17 is a diagram showing the degree of crystallization according to the molar ratio of SiO 2 / Al 2 O 3 ;
18 is a graph showing Cu 2 + ion exchange capacity in a zeolite according to the molar ratio of SiO 2 / Al 2 O 3 ;
19 is a graph showing the Zn 2 + ion exchange capacity in a zeolite according to the molar ratio of SiO 2 / Al 2 O 3 ;

Hereinafter, a method for synthesizing zeolite using fly ash according to the present invention will be described in detail with reference to the accompanying drawings.

Experimental material

In order to synthesize zeolite, a fly ash of H Company was used. The characteristics of fly ash are the same as those of Table 1 (Chemical composition of FA and the Z-WK).

Sample Composition (wt%) Total SiO 2 Al 2 O 3 Na 2 O CaO SO 3 Fe 2 O 3 MgO TiO 2 etc. FA 51.06 17.37 0.75 14.15 4.69 6.84 1.63 0.65 2.86 100 Z-WK 47.32 34.87 17.66 0.07 0.03 0.03 - - 0.02 100

Reagent grade zeolite (Wako, zeolite 4A; hereinafter Z-WK) was used as the Na-A zeolite standard material. Figure 1 is a SEM image of FA and Z-WK used in zeolite synthesis.

Experimental Method

end. Zeolite synthesis

The method of synthesis of zeolite using fly ash is based on the hydrothermal synthesis method (Murayama et al. (2002)) and the melting, melting and hydrothermal synthesis method (Molina et al. Were applied. The process of synthesizing zeolite using fly ash is shown in Fig.

Na 2 CO 3 / FA molar ratio is 0.6 ~ 4.0 (w / w) in the baked for one hour at 900 ℃ and injecting a plastic material into a Teflon reactor of 500mL was added to NaAlO 2 SiO 2 / Al 2 O 3 The molar ratio was adjusted to 1.5 to 4.0. In order to increase the synthesis efficiency, 1 wt% of Z-WK was added. The mixed material was stirred at room temperature for 5 hours, then heated to 90 ° C for 1 hour, and stirred at 90 ° C for 5 hours. The synthesized material was filtered and washed, and dried at 105 to 110 ° C for 24 hours.

Table 2 below shows the experimental results for the Na 2 CO 3 / FA molar ratio, the NaAlO 2 addition amount, and the SiO 2 / Al 2 O 3 And the molar ratio.

FA contents (10g) Additive SiO 2 / Al 2 O 3 (mol / mol) SiO 2 (mol) Al 2 O 3 (mol) Na 2 CO 3 (g) NaAlO 2 (g) 0.085 0.017 6 12.3 1.5  7.9 2.0  5.3 2.5  3.5 3.0  1.3 4.0 9 12.3 1.5 12 12.3 1.5  7.9 2.0  5.3 2.5  3.5 3.0  1.3 4.0 18 12.3 1.5  7.9 2.0  5.3 2.5  3.5 3.0  1.3 4.0 24 12.3 1.5  7.9 2.0  5.3 2.5  3.5 3.0  1.3 4.0 30 12.3 1.5 40 12.3 1.5

In order to control the molar ratio of SiO 2 / Al 2 O 3 in the flyash, the addition amount of NaAlO 2 was calculated in the following manner. First, the amounts of SiO 2 and Al 2 O 3 in the 10 g fly ash were calculated as shown in Table 2.

I. Metal adsorption experiment

Adsorption performance of Cu 2 + and Zn 2 + ions was analyzed to compare cation exchange capacity of zeolite. Heavy metal standard solutions were prepared using reagent grade Cu (NO 3 ) 2 · 3H 2 O (Junsei Co., 99%) and Zn (NO 3 ) 2 · 6H 2 O (Shinyo Co., 95% / L. ≪ / RTI > The pH of the aqueous solution was adjusted to 4 using HNO 3 (Samchun, 60%) since the aqueous solution of Cu 2 + and Zn 2 + ions forms a hydrate at pH 6 or higher. Adsorption experiments were carried out by adding 0.2 g of synthetic zeolite in a 250 mL Erlenmeyer flask with Cu 2 + and Zn 2 + aqueous solutions, stirring the mixture at 30 ° C and 130 rpm for 2 hours using a water bath, The supernatant was collected by centrifugation at 2000 rpm for 5 minutes using a centrifuge to collect the supernatant, and the concentration of heavy metals was measured using an atomic absorption spectrophotometer (AAS: PerkinElmer, AAnalyst 300).

Analysis method

The composition and structure of the zeolite were determined by using an X-ray diffraction analyzer (XRD: D8 Advance, Bruker AXS) and an X-ray fluorescence analyzer (XRF: PHILPS PW2400). To confirm the optical structure of the zeolite, SEM: Hitachi, S-4200). The XRD analysis conditions were set to 40 kV and 40 mA using Cu Ka ray (λ = 1.54 Å), and the pow- er-shaped specimen was injected to adjust the 2θ (diffraction angle) from 5 ° to 50 ° to 0.02 ° step (3s / step). The XRF specimen was dried at 105 ° C for about 28 hours to prepare a pellet. The analysis conditions of the XRF were set to 50 kV and 600 μA for the acceleration voltage and for the analysis time to 200 seconds, respectively.

Results and discussion

1. Effect of zeolite synthesis conditions

end. Na 2 CO 3 / FA Mole ratio

The effect of the alkali addition was examined by comparing the structure and the characteristics of the synthesized zeolite after controlling the Na 2 CO 3 / FA molar ratio in the range of 0.6 to 4.0 as shown in Table 2. Figure 3 shows the XRD pattern of the synthesized zeolite according to the Na 2 CO 3 / FA molar ratio. The peaks of zeolite were not observed at Na 2 CO 3 / FA molar ratio of 0.6, indicating that SiO 2 and Al 2 O 3 contained in fly ash could not be synthesized with zeolite. The peak of Na-A type zeolite at the same 2θ (7.18, 10.17, 12.46, 16.11, 21.67, 23.99, 26.11, 27.11, 29.94) position as that of Z-WK under the condition of Na 2 CO 3 / I could confirm.

This peak was almost at the same position as the XRD peak of Na-A type zeolite (Na 12 Al 12 Si 12 O 48 .27.4H 2 O). The peak of the Na-A zeolite tended to increase with increasing Na 2 CO 3 / FA molar ratio from 1.2 to 2.4. In the conventional hydrothermal synthesis, the amount of Si and Al eluted from fly ash was compared according to the alkali concentration. At 2.0 and 3.5 M NaOH concentrations, 0.2 and 0.3 M and 0.05-0.18 M of Si and Al were eluted, respectively. In this condition, SiO 2 / Al 2 O 3 The molar ratio of 1.7 makes it possible to synthesize Na-Pl type zeolite, but SiO 2 / Al 2 O 3 The results of the synthesis of hydroxysodalite and the absence of zeolite were reported under the condition that the molar ratio is 1.0.

In the fusion / hydrothermal synthesis method of the present invention, it was confirmed that when the molar ratio of Na 2 CO 3 / FA is increased, much blue-green Si and Al are eluted on the surface of the calcined material. Therefore, when the molar ratio of Na 2 CO 3 / FA is low, it is considered that the synthesis of Na-A type zeolite is hardly proceeded because the elution amount of Si and Al is small. As Na 2 CO 3 / FA molar ratio is increased, Na- And the peak of the < / RTI > However, when Na 2 CO 3 / FA molar ratio was 3.0, the peak of Na-A type zeolite tended to decrease again. In the present invention, the optimum Na 2 CO 3 / FA molar ratio in which Na-A type zeolite can be synthesized is SiO 2 / Al 2 O 3 The molar ratio was in the range of 1.8 to 2.4 under the condition of 1.5.

SiO 2 / Al 2 O 3 The effect of alkali addition on the molar ratio of Na 2 CO 3 / FA and SiO 2 / Al 2 O 3 The molar ratios were controlled in the range of 0.6 ~ 2.4 and 1.5 ~ 3.0, respectively, and the structure and properties of the synthesized zeolite were compared. FIG. 4 shows an XRD pattern according to the molar ratio of Na 2 CO 3 / FA when the molar ratio of SiO 2 / Al 2 O 3 is 1.5. Peaks of zeolite were not observed at Na 2 CO 3 / FA molar ratio of 0.6, and the synthesis of SiO 2 and Al 2 O 3 contained in fly ash was hardly proceeded with zeolite. However, a peak at the same position as Z-WK could be confirmed under the condition of Na 2 CO 3 / FA molar ratio of 1.2 or more as shown in FIG. 4 (b). FIG. 5 shows an XRD pattern according to the molar ratio of Na 2 CO 3 / FA when the molar ratio of SiO 2 / Al 2 O 3 is 2.0. When the Na 2 CO 3 / FA molar ratio is 0.6, the peak of the Na-A type zeolite begins to appear unlike in FIG. 4, and the peak of the Na-A type zeolite at a Na 2 CO 3 / FA molar ratio of 1.2 to 1.8 peak was found to be highest, and a peak corresponding to calcite (CaO) was observed at a Na 2 CO 3 / FA molar ratio of 2.4 to 2θ of 29.45. 6 is a SiO 2 / Al 2 O 3 XRD pattern of the zeolite synthesized by controlling the molar ratio to 2.5. When the Na 2 CO 3 / FA molar ratio is 0.6, no peak appears as shown in FIG. 4 (a), and when the Na 2 CO 3 / FA molar ratio is 1.2 or more, the Na- The peak of the zeolite was confirmed. 7 is a SiO 2 / Al 2 O 3 The XRD pattern of the zeolite synthesized by controlling the molar ratio to 3.0 is shown. FIG. 7 (b) is a cross-sectional view of the SiO 2 / Al 2 O 3 Although the molar ratio showed a lower peak height than that of 1.5 to 2.5, the peak of Na-A type zeolite was high at the Na 2 CO 3 / FA molar ratio of 1.8 and 2.4. SiO 2 / Al 2 O 3 The molar ratio of SiO 2 / Al 2 O 3 The calcite peaks corresponding to the impurities were increased in the molar ratios of 2.5 and 3.0.

SiO 2 / Al 2 O 3 The peak of Na-A type zeolite was high in the Na 2 CO 3 / FA molar ratio of 1.2 ~ 1.8 under the condition of the molar ratio of 2.0, but calcite peak was hardly formed. However, SiO 2 / Al 2 O 3 In the condition of molar ratio of 2.5 or more, the peak of Na-A type zeolite was high at the Na 2 CO 3 / FA molar ratio of 1.2 to 2.4, but the calcite peak also tended to be high. Therefore, the optimum SiO 2 / Al 2 O 3 The molar ratio of Na 2 CO 3 / FA ranged from 1.2 to 1.8 at a molar ratio of 2.0.

I. SiO 2 / Al 2 O 3 Mole ratio

SiO 2 / Al 2 O 3 molar ratio is compared to the structure and characteristics of the zeolite composite by adjusting the range 1.5 to 4.0. FIG. 8 shows the XRD pattern of the synthetic zeolite according to the molar ratio of SiO 2 / Al 2 O 3 at Na 2 CO 3 / FA molar ratio of 0.6. When the SiO 2 / Al 2 O 3 molar ratio was 2.0, it was confirmed that the peaks of the Na-A type zeolite were formed at a low intensity peak, unlike the other Na 2 CO 3 / FA molar ratio, in FIG. 8 (b). Figure 9 shows the XRD pattern of the synthetic zeolite of the SiO 2 / Al 2 O 3 mole ratio in the Na 2 CO 3 / FA molar ratio of 1.2. The peak of the Na-A type zeolite was found to be high at the SiO 2 / Al 2 O 3 molar ratio of 1.5 to 3.0, and the SiO 2 / Al 2 O 3 It has a maximum peak height when the molar ratio is 2.0, and SiO 2 / Al 2 O 3 As the molar ratio increased, the peak height gradually decreased, and SiO 2 / Al 2 O 3 When the molar ratio was 4.0 or more, the peak height tended to decrease. FIG. 10 shows the XRD pattern of synthetic zeolite according to the molar ratio of SiO 2 / Al 2 O 3 at Na 2 CO 3 / FA molar ratio of 1.8. Na 2 CO 3 / FA molar ratio of 1.8 is seen a high peak at a SiO 2 / Al 2 O 3 molar ratio, and it was confirmed that the SiO 2 / Al 2 O 3 molar ratio shown in Fig calcite peak height at 2.5 and 3.0. Figure 11 shows the XRD pattern of the synthetic zeolite of the SiO 2 / Al 2 O 3 mole ratio in the Na 2 CO 3 / FA molar ratio of 2.4. 10 shows that the Na-A type zeolite peaks exhibit high strength in the entire SiO 2 / Al 2 O 3 molar ratio, but the height of the calcite peak in the range of SiO 2 / Al 2 O 3 molar ratio of 2.5 to 4.0 Of the total population.

Melting and analysis of the XRD pattern of using a hydrothermal synthesis method produced according to the Na 2 CO 3 / FA molar ratio with SiO 2 / Al 2 O 3 molar ratio of zeolite and the Z-WK in accordance with the Na 2 CO 3 / FA molar ratio higher A Na-A zeolite peak appears at the same position. In the case of a synthetic zeolite with the fly ash in accordance with this result Na 2 CO 3 is estimated that the degree of crystallization of Na-A type zeolite is increased in accordance with the / FA molar ratio, the SiO 2 / Al When a Na 2 CO 3 / FA molar ratio is low 2 O 3 molar ratio has a great influence on the synthesis of Na-A type zeolite, but as the molar ratio of Na 2 CO 3 / FA increases, SiO 2 / Al 2 O 3 It was confirmed that most of the Na-A type zeolite peaks were present regardless of the molar ratio.

FIG.2CO3/ FA molar ratio of 0.62/ Al2O3 SEM image of the synthesized compound according to the molar ratio is shown. The crystal structure of the synthesized material was compared with the Z-WK crystal structure of FIG. 1 (b), and the crystal structure of the cube was not observed, indicating that Na-A type zeolite was not synthesized. Fig.2CO3/ FA molar ratio of 1.2. Unlike the result of the Na-A type zeolite peak being clearly observed in the XRD pattern shown in Fig. 9 (b), SiO2/ Al2O3 A part of the cube having the crystal structure of the Na-A type zeolite could be observed under the condition of the molar ratio of 2.0,2/ Al2O3In the molar ratio, the formation of the crystal structure was hardly achieved. Fig.2CO3/ FA molar ratio of 1.8. SiO2/ Al2O3 When the molar ratio was 1.5, relatively small cube of about 1 ~ 2 ㎛ was observed, and SiO2/ Al2O3 As the molar ratio increased, it was confirmed that the Na-A type zeolite crystals grow at a diameter of about 3 탆 or more. Fig.2CO3/ FA molar ratio is 2.4. 14,2/ Al2O3 A cube of Na-A type zeolite having a diameter of about 3 to 5 탆 was identified in the range of 2.0 to 3.0 in mole ratio,2/ Al2O3It was confirmed that crystals grow as the molar ratio increases. And SiO2/ Al2O3When the molar ratio was 4.0, the largest crystal structure was confirmed. As a result, Na2CO3/ FA molar ratio is low, it is judged that the formation of zeolite crystals does not occur properly because the amounts of Si and Al eluted from fly ash are small. Also, Na2CO3SEM image shows that the diameter of the cube becomes gradually larger as the Na / A mole ratio increases.

2. Crystallinity comparison

To compare the efficiency of synthesis of the Na-A type zeolite synthesized under various Na 2 CO 3 / FA molar ratios (0.6 to 2.4) and SiO 2 / Al 2 O 3 molar ratios (1.5 to 4.0) A type zeolite peak value corresponding to the proposed 2θ (7.18, 10.17, 12.46, 16.11, 21.67, 23.99, 26.11, 27.11, 29.94) position is integrated and the sum is divided by the value of Z-WK, Type zeolite. The crystallinity for the reference material (Na-A zeolite) is the peak size fraction of the crystallization material and can represent the purity of the reference material. The crystallinity of the synthetic zeolite was calculated using the following equation (1).

Figure pat00001

The Na 2 CO 3 / FA molar ratio and the SiO 2 / Al 2 O 3 molar ratio are in the range of 0.6 to 2.4 and 1.5 to 4.0, respectively, as shown in Table 3 below (Table 3) And the crystallinity of the Na-A type zeolite synthesized under the above conditions is calculated according to the above formula (1).

SiO 2 / Al 2 O 3 ratio

Na 2 CO 3 / FA ratio 1.5 2.0 2.5 3.0 4.0 0.6 26.89 34.80 24.12 21.54 23.50 1.2 41.18 46.46 43.09 40.75 34.77 1.8 52.68 52.95 54.97 54.23 48.16 2.4 48.56 51.56 54.93 53.23 51.05

The crystallization degree of Na 2 CO 3 / FA was 0.6 and the molar ratio of SiO 2 / Al 2 O 3 was in the range of 1.5 ~ 2.0. The ratio of Na 2 CO 3 / FA was 1.8 ~ 2.4 at SiO 2 / The crystallinity was 50% or more regardless of the Al 2 O 3 molar ratio. When the molar ratio of SiO 2 / Al 2 O 3 was 2.5, the maximum crystallinity was 54.97%. 16 shows the degree of crystallization according to the molar ratio of Na 2 CO 3 / FA. As the molar ratio of Na 2 CO 3 / FA increased from 0.6 to 2.4, the degree of crystallization gradually increased. When the molar ratio of Na 2 CO 3 / FA was 1.8 or more, the molar ratio of SiO 2 / Al 2 O 3 The degree of crystallization tended to increase. FIG. 17 shows the degree of crystallization according to the molar ratio of SiO 2 / Al 2 O 3 . The condition of Na 2 CO 3 / FA molar ratio of 0.6 and 1.2 shows a relatively high degree of crystallization at a molar ratio of SiO 2 / Al 2 O 3 of Na-A type zeolite of 2.0, but when the molar ratio of Na 2 CO 3 / FA is 1.8 or more The crystallinity of Na-A type zeolite increased to about 50%, and it was found that it was hardly affected by the molar ratio of SiO 2 / Al 2 O 3 .

3. Ion exchange capacity of zeolite

Adsorption performance of the synthesized zeolite was analyzed to evaluate the exchange ability of Cu 2 + and Zn 2 + ions. The concentrations of Cu 2 + and Zn 2 + ions were 3.125 and 3.058 mmol / L, respectively, and the pH of the solution was adjusted to 4. FIG. 18 shows the Cu 2 + ion exchange capacity in the zeolite according to the SiO 2 / Al 2 O 3 mole ratio. Cu 2 + ion exchange capacity is Z-WK is 1.40 mmol / g was, SiO 2 / Al 2 O 3 molar ratio is 1.5 days when 0.60 ~ 0.98 mmol / g of Cu 2 + having an ion exchange capacity SiO 2 / Al 2 O 3 molar ratio, the Cu 2 + ion exchange capacity tended to increase and the highest Cu 2 + ion exchange capacity in the range of 1.05 ~ 1.12 mmol / g when SiO 2 / Al 2 O 3 molar ratio was 2.5 . When in the condition of pH 4 Cu 2 + ion exchange when Na 2 CO 3 / FA molar ratio with SiO 2 / Al 2 O 3 molar ratio of 2.4 and 2.5 each one has the highest Cu 2 + ion exchange capacity of 1.12 mmol / g , And Z-WK, the performance was 80% as compared with the Cu 2 + ion exchange capacity of Z-WK. FIG. 19 shows the Zn 2 + ion exchange capacity in the zeolite according to the molar ratio of SiO 2 / Al 2 O 3 . Zn 2 + ion exchange capacity is Z-WK is 1.50 mmol / g was, SiO 2 / Al 2 O 3 molar ratio is 1.5 days when 0.87 ~ 1.06 mmol / g for Zn 2 + having an ion exchange capacity SiO 2 / Al 2 O 3 , the Zn 2 + ion exchange capacity tended to increase with increasing molar ratio, and the highest Zn 2 + ion exchange capacity was observed in the range of 1.17 ~ 1.26 mmol / g at SiO 2 / Al 2 O 3 molar ratio of 2.5 . The maximum Zn 2 + ion exchange capacity of 1.26 mmol / g when the Na 2 CO 3 / FA molar ratio and the SiO 2 / Al 2 O 3 molar ratio were 2.4 and 2.5 at the exchange of Zn 2 + ion at pH 4, respectively, Compared with Z-WK, Z-WK showed 84% performance compared with Zn 2 + ion exchange capacity. As the Si / Al ratio increases, the cation exchange capacity increases. At 2.0, the maximum cation exchange capacity is 2.30 mmol / g. As the Na 2 CO 3 / FA molar ratio increased, the Cu 2 + and Zn 2 + ion exchange capacity of the synthesized zeolite increased. In addition, Na 2 CO 3 / FA molar ratio of Na-A type zeolite in the range 1.2 to 2.4 and a crystallinity Cu 2 + and Zn 2 Ion exchange capacity was increased.

conclusion

The present coal fly ash (FA) Na 2 CO 3 / FA molar ratio with SiO 2 / Al 2 O 3 ratio exchange capacity of the synthetic zeolite and the Cu 2 +, Zn 2 + ions with different using generated in H used in the invention The following conclusions were obtained.

1. Effect of Na 2 CO 3 / FA molar ratio of (0.6 ~ 4.0) in the zeolite synthesis using the fly ash is SiO 2 / Al 2 O 3 Na -A when the molar ratio is 1.8 days Na 2 CO 3 / FA in the molar ratio 1.5 of the conditions Type zeolite showed the highest peak and the peak gradually decreased with increasing Na 2 CO 3 / FA molar ratio. The synthesized materials with Na 2 CO 3 / FA molar ratios ranging from 1.8 to 2.4 showed a crystal structure of cube having the characteristics of Na-A type zeolite on the SEM image.

2. SiO 2 / Al 2 O 3 The synthesis conditions of the Na-A type zeolite in the range of the molar ratio of 1.5 to 4.0 were Na 2 CO 3 / FA molar ratio and SiO 2 / Al 2 O 3 The molar ratios were 1.8 and 2.0, respectively. In this condition, Na-A type zeolite with 52.95% crystallinity could be synthesized without the formation of other crystal structures such as caclite. In addition, a material such as cacite is generated but the maximum crystallinity is 54.97%. The condition of Na 2 CO 3 / FA and SiO 2 / Al 2 O 3 And the molar ratios were 1.8 and 2.5, respectively.

3. As the Na 2 CO 3 / FA molar ratio increases, the XRD peak and crystallinity of the synthesized zeolite are increased. SEM image analysis shows that the crystal structure grows in the range of about 1 ~ 5 ㎛.

4. The cation exchange capacity of Cu and Zn at pH 4 was in the range of 0.6 ~ 1.12 and 0.87 ~ 1.26 mmol / g, respectively, and the zeolite contents of the synthesized zeolite were 80 ~ 84% performance was achieved. The crystallinity and cation exchange capacity of the synthesized zeolite increased with increasing Na 2 CO 3 / FA molar ratio.

As described above, an optimal embodiment has been disclosed in the drawings and specification. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (20)

A zeolite synthesis method for adding Na 2 CO 3 to a flyash (FA) comprising SiO 2 and Al 2 O 3 ,
Wherein when the molar ratio of SiO 2 / Al 2 O 3 is 1.5 or more, the molar ratio of Na 2 CO 3 / FA is increased to 0.9 or more to synthesize a zeolite having the characteristics of NA-A type zeolite.
The method according to claim 1,
Wherein the molar ratio of Na 2 CO 3 / FA is adjusted to 1.8 to 2.4 when the mole ratio of SiO 2 / Al 2 O 3 is 1.5.
The method according to claim 1,
Wherein when the molar ratio of SiO 2 / Al 2 O 3 is 2.0, the molar ratio of Na 2 CO 3 / FA is adjusted to 1.2 to 1.8.
The method according to claim 1,
Wherein the molar ratio of Na 2 CO 3 / FA is increased to 1.2 or more when the molar ratio of SiO 2 / Al 2 O 3 is 2.5.
The method according to claim 1,
Wherein the molar ratio of Na 2 CO 3 / FA is increased to 1.2 or more when the mole ratio of SiO 2 / Al 2 O 3 is 3.0.
6. The method of claim 5,
Wherein the molar ratio of Na 2 CO 3 / FA is adjusted to 1.8 to 2.4.
A zeolite synthesis method for adding Na 2 CO 3 to a flyash (FA) comprising SiO 2 and Al 2 O 3 ,
Na 2 CO 3 / FA when the molar ratio of 0.6 or more, the zeolite synthesis method characterized in that the synthetic zeolite and the molar ratio of SiO 2 / Al 2 O 3 is increased by 1.5 or more NA with characteristics of A-type zeolite.
8. The method of claim 7,
Wherein when the molar ratio of Na 2 CO 3 / FA is 1.2, the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 1.5 to 4.0.
9. The method of claim 8,
Wherein the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 2.0.
8. The method of claim 7,
The Na 2 CO 3 / FA when the molar ratio of 1.8 days, synthetic zeolite characterized in that fits with the SiO 2 / Al 2 O 3 1.5 to 4.0 and the molar ratio of.
11. The method of claim 10,
Wherein the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 2.0.
8. The method of claim 7,
Wherein the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 1.5 to 4.0 when the molar ratio of Na 2 CO 3 / FA is 2.4.
A zeolite synthesis method for adding Na 2 CO 3 to a flyash (FA) comprising SiO 2 and Al 2 O 3 ,
Wherein the molar ratio of Na 2 CO 3 / FA is increased to synthesize a zeolite having characteristics of NA-A type zeolite having a high degree of crystallinity.
14. The method of claim 13,
Wherein the molar ratio of Na 2 CO 3 / FA is adjusted to 1.2 to 2.4.
15. The method of claim 14,
When the molar ratio of Na 2 CO 3 / FA is 1.8, the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 1.5 to 4.0. The higher the molar ratio of SiO 2 / Al 2 O 3 is, the higher the crystallinity Lt; RTI ID = 0.0 > zeolite < / RTI >
15. The method of claim 14,
When the molar ratio of Na 2 CO 3 / FA is 2.4, the molar ratio of SiO 2 / Al 2 O 3 is adjusted to 2.0 to 4.0. The higher the mole ratio of SiO 2 / Al 2 O 3 is, the higher the crystallinity Lt; RTI ID = 0.0 > zeolite < / RTI >
A zeolite synthesis method for adding Na 2 CO 3 to a flyash (FA) comprising SiO 2 and Al 2 O 3 ,
Wherein the molar ratio of Na 2 CO 3 / FA is increased to synthesize a zeolite having characteristics of NA-A type zeolite having high cation exchange ability.
18. The method of claim 17,
Wherein the molar ratio of Na 2 CO 3 / FA is adjusted to 1.2 to 2.4.
18. The method of claim 17,
Wherein the SiO 2 / Al 2 O 3 molar ratio is from 1.5 to 4.0 and has an ion exchange capacity of Cu 2 + .
18. The method of claim 17,
Zeolite synthesis in that the SiO 2 / Al 2 O 3 molar ratio is from 1.5 to 4.0 characterized in that it contains the ion-exchange capacity of the Zn + 2.
KR1020120158371A 2012-12-31 2012-12-31 Method for synthesizing zeolite using fly ash KR20140088985A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107697927A (en) * 2017-11-14 2018-02-16 江苏理工学院 A kind of preparation method using flyash as the NaA molecular sieve of raw material
KR20230062969A (en) * 2021-11-01 2023-05-09 한국해양대학교 산학협력단 Manufacturing method of zeolite-p using residual by-products generated in the indirect carbonation process

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107697927A (en) * 2017-11-14 2018-02-16 江苏理工学院 A kind of preparation method using flyash as the NaA molecular sieve of raw material
KR20230062969A (en) * 2021-11-01 2023-05-09 한국해양대학교 산학협력단 Manufacturing method of zeolite-p using residual by-products generated in the indirect carbonation process

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