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CO2 adsorption behavior of microwave synthesized zeolite beta
Materials Letters 108 (2013) 106–109
Contents lists available at SciVerse ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
CO2 adsorption behavior of microwave synthesized zeolite beta Hyo-Sang You, Hailian Jin, Yong-Hwan Mo, Sang-Eon Park n Laboratory of Nano-Green Catalysis and Nano Center for Fine Chemical Fusion Technology, Department of Chemistry, Inha University, Incheon 402-751, Republic of Korea
art ic l e i nf o
a b s t r a c t
Article history: Received 12 October 2012 Accepted 23 June 2013 Available online 28 June 2013
Zeolite beta was successfully synthesized by direct synthesis with addition of seeds under microwave irradiation. CO2 adsorption properties on the microwave synthesized zeolite beta were investigated at constant temperature 40 1C and absolute pressure 1 atm which compared with zeolite beta synthesized by the conventional hydrothermal method. Microwave synthesized zeolite beta showed higher CO2 adsorption capacity than that of hydrothermal synthesized zeolite beta. Even the surface area of microwave synthesized zeolite beta (463 m2/g) was similar with hydrothermal synthesized one (482 m2/g), higher aluminum contents and the less hydrophilicity of microwave synthesized zeolite beta contributed to the higher adsorption capacity and selectivity of CO2 than those of hydrothermal synthesized one, respectively. & 2013 Elsevier B.V. All rights reserved.
Keywords: Zeolite beta Microwave synthesis CO2 adsorption Hydrophilicity Water adsorption
1. Introduction Zeolites are crystalline aluminosilicates with diverse framework structures considered as efficient adsorbents with high adsorption capacities for wide variety of adsorbates [1,2]. Moreover, these zeolite-based adsorbents show good regeneration properties with fresh adsorption capacities even after recycling several times [3]. Recently, CO2 adsorption on zeolites received much attention due to CO2 as green house gas causing global warming [4–6]. Zeolites showed higher adsorption capacities of CO2 compared with other adsorbents such as hydrotalcites or metal oxide due to their high affinity for polar molecules at low partial pressures and mild temperatures [3,7]. Various types of zeolites such as LTA [8], FAU [9], MOR [10], and MFI [11] have been applied for CO2 adsorption studies and are reported earlier. Zeolite beta is one of typical representative large-pore zeolites having open framework structure with three-dimensional 12membered ring channels (0.76 0.64 and 0.55 0.55 nm) which shows large micropore volume, high surface area, tunable Si/Al ratios and ion-exchange capacities [12,13]. Owing to such unique properties, recently zeolite Beta has been demonstrated as a potential adsorbent for CO2 adsorption. The investigation on zeolite beta for adsorption and separation of CO2, O2, N2, and CH4 was firstly reported by Tezel et al. [14]. They observed that the highest Henry Law constant and good equilibrium separation factors were obtained in the CO2 adsorption among the gas mixtures over zeolite beta. The similar studies were performed
n
Corresponding author. Tel: +82 32 860 7675. Fax: +82 32 872 8670. E-mail address: [email protected] (S.-E. Park)
0167-577X/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.matlet.2013.06.088
on H-beta, Na-beta and monoethanol amine modified beta reported by Liu et al. [15,16]. Very recently, Ahn et al. [17] investigated the effect of ion-exchanged alkali and alkaline cations such as Li+, K+, Cs+, Mg2+, Ca2+ and Ba2+ on CO2 adsorption in zeolite beta. They found that the K+-exchanged zeolite beta showed the highest CO2 adsorption capacity compared with other cations. In general, these earlier studies were performed with zeolites synthesized by the conventional hydrothermal method which required longer synthetic times. According to our previous reports, the microwave-mediated synthesis (MW) could provide not only shorter synthetic times but also unique advantages such as uniform morphology, phase control and the enhanced hydrophobicity compared with the conventional hydrothermal synthesis method (HT) [18]. In continuation to our prior studies on microwave mediated synthesis of zeolite beta under fluoride media [19], in this work we report CO2 adsorption behavior on the microwave synthesized zeolite beta which compared with conventional hydrothermal synthesized zeolite beta. 2. Experimental section Synthesis of zeolite beta: Microwave synthesized zeolite beta (beta-MW)—The microwave synthesized zeolite beta was prepared by following procedure. Initially, the tetraethylammonium hydroxide (TEAOH, Aldrich Co., 40 wt %), sodium aluminate (Junsei Co., 37% Na2O, 54% Al2O3), NaOH (Duksan Co., 93%) and seed solution (commercial zeolite Beta from Zeolyst Co. was dissolved in water) were mixed and vigorously stirred for 5 min. To this
H.-S. You et al. / Materials Letters 108 (2013) 106–109
solution, Ludox HS-40 (Aldrich Co., 40% colloidal silica) was slowly added then stirred for 5 min. The molar composition of synthesis mixture was 1SiO2:0.04Al2O3:0.09Na2O:0.81TEAOH:28.4 H2O. The resulting mixture was loaded in a microwave oven equipped with a Teflon autoclave (CEM Co., MARS-5) and irradiated at 170 1C for 4 h under 1200 W of microwave power. The resulting product was filtered, washed with distilled water and dried at 80 1C for 24 h in the oven. As-synthesized sample was calcined at 550 1C for 6 h in the air. Hydrothermal synthesized zeolite beta (beta-HT)—The synthesis procedure was same with that of Beta-MW except the heating method, whereby the resulted precursor gel in the pressure vessel was loaded to thermal oven at 170 1C for 48 h instead of microwave irradiation. Characterization—Powder X-ray diffraction patterns (XRD) were obtained using Rigaku Miniflex X-ray diffractometer with
107
CuKα radiation source (λ ¼0.154 nm) at 30 kV, 15 mA from 51 to 401. Surface area were determined by the N2 adsorption–desorption isotherms at 77 K (Micromeritics ASAP2020 analyzer). The Scanning Electron Microscope (SEM) was used for observing morphologies using Hitachi S-4300SE and chemical analysis was done by using Inductively Coupled Plasma Spectrometer (ICP; Optima 7300DV). Adsorption isotherms of CO2 and H2O—All samples were pretreated at 140 1C for 4 h under vacuum prior to get CO2 and H2O isotherms. The CO2 isotherms were obtained in Micromeritics ASAP2050 analyzer at constant temperature 40 1C with the absolute pressures range from 1 mmHg to 760 mmHg. For the water adsorption, the isotherms were performed in the same equipment (Micromeritics ASAP2050 analyzer) at constant temperature 25 1C under the relative pressures range from 0.01 to 0.8P/P0.
3. Results and discussion
Fig. 1. XRD patterns of Beta-MW and Beta-HT.
The XRD patterns of microwave synthesized zeolite beta (BetaMW) and conventional hydrothermal synthesized zeolite beta (Beta-HT) are shown in Fig. 1. Both samples exhibited the typical crystalline structure of beta without impurity phase in XRD patterns from the range 5 to 401. On the contrary to conventional hydrothermal synthesis required 48 h for getting highly crystalline structure of zeolite beta, the microwave irradiation enabled the synthesis of zeolite beta with high crystallinity in 4 h under 1200 W power by the seeding method. The SEM images of both Beta-MW and Beta-HT revealed well shaped crystals with uniform sized of 400–500 nm which seemed to be formed by aggregation of small crystallites (Fig. 2). The N2 adsorption–desorption isotherms showed typical type I isotherm with rectangular H4 hysteresis loops at P/P0 40.4 which was the characteristics of typical microporous materials (not shown here) [20]. The surface area of samples estimated employing the Brunauer Emmett and Teller (BET) method from N2 adsorption isotherm at P/P0 in the range of 0.1–0.3. The BET surface area and total pore volume of
Fig. 2. SEM images of (a) Beta-MW and (b) Beta-HT.
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H.-S. You et al. / Materials Letters 108 (2013) 106–109
Table 1 Textural and adsorption properties of Beta-MW and Beta-HT. Catalysts
BET surface areaa(m2/g)
Total pore volumeb (cm3/g)
CO2 adsorption capacityc (mmol/g)
H2O adsorption capacityd (mmol/g)
Selectivity on adsorbed CO2e (%)
SiO2/Al2O3f
Beta-MW Beta-HT
463 483
0.28 0.29
2.16 1.94
10.5 11.4
17.1 14.5
15.9 18.6
a
BET surface area obtained from N2 adsorption isotherm in the relative pressure range of 0.1–0.3. Total pore volume was derived at P/P0 ¼ 0.97. c The capacity was obtained at absolute pressure 760 mmHg. d The capacity was obtained at relative pressure 0.8 P/P0. e The selectivity on CO2 was calculated by CO2 adsorption capacity/CO2+H2O adsorption capacity. f The molar ratio was calculated from Aluminum concentration obtained by ICP. b
Fig. 3. (a) CO2 and (b) water adsorption isotherms of Beta-MW and Beta-HT.
Beta-MW were 463 m2/g and 0.28 cm3/g, respectively (Table 1). It was similar with those of Beta-HT (483 m2/g and 0.29 cm3/g). Generally, the adsorption of CO2 behavior into zeolites is influenced by the electric field generated by the presence of cation and surface silanol group. Fig. 3a showed the CO2 adsorption isotherms of both Beta-MW and Beta-HT obtained at constant temperature 40 1C with the absolute pressures range from 1 to 760 mmHg. The equilibrium adsorption capacity for CO2 on BetaMW (2.16 mmol/g at 760 mmHg) was higher than that of Beta-HT (1.94 mmol/g at 760 mmHg) even having similar surface area and total pore volume as summarized in Table 1. The enhanced adsorption capacity for CO2 on Beta-MW was mainly attributed to higher Al content which can be seen from lower molar ratio of SiO2/Al2O3. As earlier report by Dunne et al. [21] the adsorption properties of zeolite affected due to higher sodium content. The presence of Al atom in zeolites introduced negative framework charges which require charge-compensating Na+ cation which enables zeolites to adsorb acidic gas such as CO2 [3]. Another more effective enhancement on CO2 selectivity was resulted from less hydrophilicity property of Beta-MW which was confirmed by water adsorption isotherms at constant temperature 25 1C with the relative pressures at P/P0 from 0.01 to 0.8 as shown in Fig. 3b. The water absorbed amount of Beta-MW was 10.5 mmol/g at relative pressure 0.8 P/P0 which was lower than that of Beta-HT (11.3 mmol/g) in Table 1. Moreover, the selectivity on CO2 over Beta-MW (17.1%) was higher than Beta-HT (14.5%). It was indicated that the Beta-MW is relatively less hydrophilic compared with Beta-HT. This observation was in agreement with our previous studies on microwave synthesized zeolites [22].
4. Conclusion The zeolite beta with high crystallinity was rapidly synthesized within 4 h under microwave irradiation without fluoride media. The microwave synthesized zeolite beta exhibited enhanced CO2 adsorption capacity (2.16 mmol/g) and selectivity on CO2 (17.1%) than those of conventional hydrothermal synthesized zeolite beta (1.94 mmol/g and 14.5%) even similar BET surface area and pore volume. This result was not only attributed to high aluminum content but also less hydrophilicity of microwave synthesized zeolite.
Acknowledgment This work was supported by the Korea Institute of Energy Research (KIER) (No. KIER-B1-2408) and National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 20090083525). References [1] Park SE, Jiang NZ. Morphological synthesis of zeolite. In: Cejka J, Corma A, editors. Zeolite and catalysis synthesis. reaction and application. Weinhein: Wiley-VCH4CO. KGaA; 2010. p. 131–50. [2] Walton KS, Abney MB, Levan MD. Microporous Mesoporous Mater 2006;91:78–84. [3] Choi S, Drese JH, Jones CW. ChemSusChem 2009;2:794–854. [4] Haszeldine RS. Science 2009;325:1647–52. [5] Miyamoto M, Fujioka Y, Yogo K. J Mater Chem 2012;22:20186–9.
H.-S. You et al. / Materials Letters 108 (2013) 106–109
[6] Bezerra DP, Oliveira RS, Vieira RS, Cavalcante Jr CL, Azevedo DCS. . Adsorption 2011;17:235–46. [7] Alessandro DMD, Smit B, Long JR. Angew Chem Int Ed. 2010;49:6058–82. [8] Akten ED, Sriwardane R, Sholl DS. Energy Fuels 2003;17:977–83. [9] Boisgontier CD, Parmentier J, Faour A, Patarin J, Pirngruber GD. Energy Fuels 2010;24:3595–602. [10] Sanchez AG, Ania CO, Parra JB, Dubbeldam D, Vlugt TJH, Krishna R, et al. J Phys Chem C 2009;113:8814–20. [11] Perez EG, Parra JB, Ania CO, Sanchez AG, van Baten JM, Krishna R, et al. Adsorption 2007;13:469–76. [12] Higgins JB, LaPierre RB, Schlenker JL, Rohrman AC, Wood JD, Kerr GT, et al. Zeolites 1983;8:446–52. [13] Newsam JM, Treacy MMJ, Koetsier WT, De Gruyter CB. Proc R Soc London A 1988;420:375–405.
[14] [15] [16] [17] [18] [19] [20] [21] [22]
109
Li P, Tezel FH. Microporous Mesoporous Mater 2007;98:94–101. Xu X, Zhao X, Sun L, Liu X. J Nat Gas Chem 2008;17:391–6. Xu X, Zhao X, Sun L, Liu X. J Nat Gas Chem 2009;18:167–72. Yang ST, Kim J, Ahn WS. Microporous Mesoporous Mater 2010;135:90–4. Park SE, Chan JS, Hwang YK, Kim DS, Jhung SH, Hwang JS. Catal Surv Asia 2004;2:91–110. Kim DS, Chang JS, Hwang JS, Park SE, Kim JM. Microporous Mesoporous Mater 2004;68:77–82. Kruk M, Jaroniec M. Chem Mater 2001;13:3169–83. Dunne JA, Rao M, Sircar S, Gorte RJ, Myers AL. Langmuir 1996;12:5896–904. Xu CH, Jin T, Jhung SH, Chang JS, Hwang JS, Park SE. Catal Today 2006;111:366–72.
Contents lists available at SciVerse ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/matlet
CO2 adsorption behavior of microwave synthesized zeolite beta Hyo-Sang You, Hailian Jin, Yong-Hwan Mo, Sang-Eon Park n Laboratory of Nano-Green Catalysis and Nano Center for Fine Chemical Fusion Technology, Department of Chemistry, Inha University, Incheon 402-751, Republic of Korea
art ic l e i nf o
a b s t r a c t
Article history: Received 12 October 2012 Accepted 23 June 2013 Available online 28 June 2013
Zeolite beta was successfully synthesized by direct synthesis with addition of seeds under microwave irradiation. CO2 adsorption properties on the microwave synthesized zeolite beta were investigated at constant temperature 40 1C and absolute pressure 1 atm which compared with zeolite beta synthesized by the conventional hydrothermal method. Microwave synthesized zeolite beta showed higher CO2 adsorption capacity than that of hydrothermal synthesized zeolite beta. Even the surface area of microwave synthesized zeolite beta (463 m2/g) was similar with hydrothermal synthesized one (482 m2/g), higher aluminum contents and the less hydrophilicity of microwave synthesized zeolite beta contributed to the higher adsorption capacity and selectivity of CO2 than those of hydrothermal synthesized one, respectively. & 2013 Elsevier B.V. All rights reserved.
Keywords: Zeolite beta Microwave synthesis CO2 adsorption Hydrophilicity Water adsorption
1. Introduction Zeolites are crystalline aluminosilicates with diverse framework structures considered as efficient adsorbents with high adsorption capacities for wide variety of adsorbates [1,2]. Moreover, these zeolite-based adsorbents show good regeneration properties with fresh adsorption capacities even after recycling several times [3]. Recently, CO2 adsorption on zeolites received much attention due to CO2 as green house gas causing global warming [4–6]. Zeolites showed higher adsorption capacities of CO2 compared with other adsorbents such as hydrotalcites or metal oxide due to their high affinity for polar molecules at low partial pressures and mild temperatures [3,7]. Various types of zeolites such as LTA [8], FAU [9], MOR [10], and MFI [11] have been applied for CO2 adsorption studies and are reported earlier. Zeolite beta is one of typical representative large-pore zeolites having open framework structure with three-dimensional 12membered ring channels (0.76 0.64 and 0.55 0.55 nm) which shows large micropore volume, high surface area, tunable Si/Al ratios and ion-exchange capacities [12,13]. Owing to such unique properties, recently zeolite Beta has been demonstrated as a potential adsorbent for CO2 adsorption. The investigation on zeolite beta for adsorption and separation of CO2, O2, N2, and CH4 was firstly reported by Tezel et al. [14]. They observed that the highest Henry Law constant and good equilibrium separation factors were obtained in the CO2 adsorption among the gas mixtures over zeolite beta. The similar studies were performed
n
Corresponding author. Tel: +82 32 860 7675. Fax: +82 32 872 8670. E-mail address: [email protected] (S.-E. Park)
0167-577X/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.matlet.2013.06.088
on H-beta, Na-beta and monoethanol amine modified beta reported by Liu et al. [15,16]. Very recently, Ahn et al. [17] investigated the effect of ion-exchanged alkali and alkaline cations such as Li+, K+, Cs+, Mg2+, Ca2+ and Ba2+ on CO2 adsorption in zeolite beta. They found that the K+-exchanged zeolite beta showed the highest CO2 adsorption capacity compared with other cations. In general, these earlier studies were performed with zeolites synthesized by the conventional hydrothermal method which required longer synthetic times. According to our previous reports, the microwave-mediated synthesis (MW) could provide not only shorter synthetic times but also unique advantages such as uniform morphology, phase control and the enhanced hydrophobicity compared with the conventional hydrothermal synthesis method (HT) [18]. In continuation to our prior studies on microwave mediated synthesis of zeolite beta under fluoride media [19], in this work we report CO2 adsorption behavior on the microwave synthesized zeolite beta which compared with conventional hydrothermal synthesized zeolite beta. 2. Experimental section Synthesis of zeolite beta: Microwave synthesized zeolite beta (beta-MW)—The microwave synthesized zeolite beta was prepared by following procedure. Initially, the tetraethylammonium hydroxide (TEAOH, Aldrich Co., 40 wt %), sodium aluminate (Junsei Co., 37% Na2O, 54% Al2O3), NaOH (Duksan Co., 93%) and seed solution (commercial zeolite Beta from Zeolyst Co. was dissolved in water) were mixed and vigorously stirred for 5 min. To this
H.-S. You et al. / Materials Letters 108 (2013) 106–109
solution, Ludox HS-40 (Aldrich Co., 40% colloidal silica) was slowly added then stirred for 5 min. The molar composition of synthesis mixture was 1SiO2:0.04Al2O3:0.09Na2O:0.81TEAOH:28.4 H2O. The resulting mixture was loaded in a microwave oven equipped with a Teflon autoclave (CEM Co., MARS-5) and irradiated at 170 1C for 4 h under 1200 W of microwave power. The resulting product was filtered, washed with distilled water and dried at 80 1C for 24 h in the oven. As-synthesized sample was calcined at 550 1C for 6 h in the air. Hydrothermal synthesized zeolite beta (beta-HT)—The synthesis procedure was same with that of Beta-MW except the heating method, whereby the resulted precursor gel in the pressure vessel was loaded to thermal oven at 170 1C for 48 h instead of microwave irradiation. Characterization—Powder X-ray diffraction patterns (XRD) were obtained using Rigaku Miniflex X-ray diffractometer with
107
CuKα radiation source (λ ¼0.154 nm) at 30 kV, 15 mA from 51 to 401. Surface area were determined by the N2 adsorption–desorption isotherms at 77 K (Micromeritics ASAP2020 analyzer). The Scanning Electron Microscope (SEM) was used for observing morphologies using Hitachi S-4300SE and chemical analysis was done by using Inductively Coupled Plasma Spectrometer (ICP; Optima 7300DV). Adsorption isotherms of CO2 and H2O—All samples were pretreated at 140 1C for 4 h under vacuum prior to get CO2 and H2O isotherms. The CO2 isotherms were obtained in Micromeritics ASAP2050 analyzer at constant temperature 40 1C with the absolute pressures range from 1 mmHg to 760 mmHg. For the water adsorption, the isotherms were performed in the same equipment (Micromeritics ASAP2050 analyzer) at constant temperature 25 1C under the relative pressures range from 0.01 to 0.8P/P0.
3. Results and discussion
Fig. 1. XRD patterns of Beta-MW and Beta-HT.
The XRD patterns of microwave synthesized zeolite beta (BetaMW) and conventional hydrothermal synthesized zeolite beta (Beta-HT) are shown in Fig. 1. Both samples exhibited the typical crystalline structure of beta without impurity phase in XRD patterns from the range 5 to 401. On the contrary to conventional hydrothermal synthesis required 48 h for getting highly crystalline structure of zeolite beta, the microwave irradiation enabled the synthesis of zeolite beta with high crystallinity in 4 h under 1200 W power by the seeding method. The SEM images of both Beta-MW and Beta-HT revealed well shaped crystals with uniform sized of 400–500 nm which seemed to be formed by aggregation of small crystallites (Fig. 2). The N2 adsorption–desorption isotherms showed typical type I isotherm with rectangular H4 hysteresis loops at P/P0 40.4 which was the characteristics of typical microporous materials (not shown here) [20]. The surface area of samples estimated employing the Brunauer Emmett and Teller (BET) method from N2 adsorption isotherm at P/P0 in the range of 0.1–0.3. The BET surface area and total pore volume of
Fig. 2. SEM images of (a) Beta-MW and (b) Beta-HT.
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H.-S. You et al. / Materials Letters 108 (2013) 106–109
Table 1 Textural and adsorption properties of Beta-MW and Beta-HT. Catalysts
BET surface areaa(m2/g)
Total pore volumeb (cm3/g)
CO2 adsorption capacityc (mmol/g)
H2O adsorption capacityd (mmol/g)
Selectivity on adsorbed CO2e (%)
SiO2/Al2O3f
Beta-MW Beta-HT
463 483
0.28 0.29
2.16 1.94
10.5 11.4
17.1 14.5
15.9 18.6
a
BET surface area obtained from N2 adsorption isotherm in the relative pressure range of 0.1–0.3. Total pore volume was derived at P/P0 ¼ 0.97. c The capacity was obtained at absolute pressure 760 mmHg. d The capacity was obtained at relative pressure 0.8 P/P0. e The selectivity on CO2 was calculated by CO2 adsorption capacity/CO2+H2O adsorption capacity. f The molar ratio was calculated from Aluminum concentration obtained by ICP. b
Fig. 3. (a) CO2 and (b) water adsorption isotherms of Beta-MW and Beta-HT.
Beta-MW were 463 m2/g and 0.28 cm3/g, respectively (Table 1). It was similar with those of Beta-HT (483 m2/g and 0.29 cm3/g). Generally, the adsorption of CO2 behavior into zeolites is influenced by the electric field generated by the presence of cation and surface silanol group. Fig. 3a showed the CO2 adsorption isotherms of both Beta-MW and Beta-HT obtained at constant temperature 40 1C with the absolute pressures range from 1 to 760 mmHg. The equilibrium adsorption capacity for CO2 on BetaMW (2.16 mmol/g at 760 mmHg) was higher than that of Beta-HT (1.94 mmol/g at 760 mmHg) even having similar surface area and total pore volume as summarized in Table 1. The enhanced adsorption capacity for CO2 on Beta-MW was mainly attributed to higher Al content which can be seen from lower molar ratio of SiO2/Al2O3. As earlier report by Dunne et al. [21] the adsorption properties of zeolite affected due to higher sodium content. The presence of Al atom in zeolites introduced negative framework charges which require charge-compensating Na+ cation which enables zeolites to adsorb acidic gas such as CO2 [3]. Another more effective enhancement on CO2 selectivity was resulted from less hydrophilicity property of Beta-MW which was confirmed by water adsorption isotherms at constant temperature 25 1C with the relative pressures at P/P0 from 0.01 to 0.8 as shown in Fig. 3b. The water absorbed amount of Beta-MW was 10.5 mmol/g at relative pressure 0.8 P/P0 which was lower than that of Beta-HT (11.3 mmol/g) in Table 1. Moreover, the selectivity on CO2 over Beta-MW (17.1%) was higher than Beta-HT (14.5%). It was indicated that the Beta-MW is relatively less hydrophilic compared with Beta-HT. This observation was in agreement with our previous studies on microwave synthesized zeolites [22].
4. Conclusion The zeolite beta with high crystallinity was rapidly synthesized within 4 h under microwave irradiation without fluoride media. The microwave synthesized zeolite beta exhibited enhanced CO2 adsorption capacity (2.16 mmol/g) and selectivity on CO2 (17.1%) than those of conventional hydrothermal synthesized zeolite beta (1.94 mmol/g and 14.5%) even similar BET surface area and pore volume. This result was not only attributed to high aluminum content but also less hydrophilicity of microwave synthesized zeolite.
Acknowledgment This work was supported by the Korea Institute of Energy Research (KIER) (No. KIER-B1-2408) and National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 20090083525). References [1] Park SE, Jiang NZ. Morphological synthesis of zeolite. In: Cejka J, Corma A, editors. Zeolite and catalysis synthesis. reaction and application. Weinhein: Wiley-VCH4CO. KGaA; 2010. p. 131–50. [2] Walton KS, Abney MB, Levan MD. Microporous Mesoporous Mater 2006;91:78–84. [3] Choi S, Drese JH, Jones CW. ChemSusChem 2009;2:794–854. [4] Haszeldine RS. Science 2009;325:1647–52. [5] Miyamoto M, Fujioka Y, Yogo K. J Mater Chem 2012;22:20186–9.
H.-S. You et al. / Materials Letters 108 (2013) 106–109
[6] Bezerra DP, Oliveira RS, Vieira RS, Cavalcante Jr CL, Azevedo DCS. . Adsorption 2011;17:235–46. [7] Alessandro DMD, Smit B, Long JR. Angew Chem Int Ed. 2010;49:6058–82. [8] Akten ED, Sriwardane R, Sholl DS. Energy Fuels 2003;17:977–83. [9] Boisgontier CD, Parmentier J, Faour A, Patarin J, Pirngruber GD. Energy Fuels 2010;24:3595–602. [10] Sanchez AG, Ania CO, Parra JB, Dubbeldam D, Vlugt TJH, Krishna R, et al. J Phys Chem C 2009;113:8814–20. [11] Perez EG, Parra JB, Ania CO, Sanchez AG, van Baten JM, Krishna R, et al. Adsorption 2007;13:469–76. [12] Higgins JB, LaPierre RB, Schlenker JL, Rohrman AC, Wood JD, Kerr GT, et al. Zeolites 1983;8:446–52. [13] Newsam JM, Treacy MMJ, Koetsier WT, De Gruyter CB. Proc R Soc London A 1988;420:375–405.
[14] [15] [16] [17] [18] [19] [20] [21] [22]
109
Li P, Tezel FH. Microporous Mesoporous Mater 2007;98:94–101. Xu X, Zhao X, Sun L, Liu X. J Nat Gas Chem 2008;17:391–6. Xu X, Zhao X, Sun L, Liu X. J Nat Gas Chem 2009;18:167–72. Yang ST, Kim J, Ahn WS. Microporous Mesoporous Mater 2010;135:90–4. Park SE, Chan JS, Hwang YK, Kim DS, Jhung SH, Hwang JS. Catal Surv Asia 2004;2:91–110. Kim DS, Chang JS, Hwang JS, Park SE, Kim JM. Microporous Mesoporous Mater 2004;68:77–82. Kruk M, Jaroniec M. Chem Mater 2001;13:3169–83. Dunne JA, Rao M, Sircar S, Gorte RJ, Myers AL. Langmuir 1996;12:5896–904. Xu CH, Jin T, Jhung SH, Chang JS, Hwang JS, Park SE. Catal Today 2006;111:366–72.