Abstract Corregido

2
Synthesis, characterization and CO 2 capture of Ce supported Y-zeolites A. A. Camacho a , J. Salmones a , M. A. Valenzuela a , B. Zeifert b , T. Vázquez c , J. L. Contreras c a Laboratorio de Catálisis y Materiales, ESIQIE IPN, México D. F., 07738, México b Departamento de Metalurgia, ESIQIE IPN, México D. F., 07738, México c Universidad Autónoma Metropolitana, Azcapotzalco, CBI Energía, México D. F., 02200, México Email: [email protected] Keywords: CO 2 , zeolites, adsorption, cerium CO 2 capture has been suggested as a possible way to mitigate climate change related to the increasing CO 2 concentration in the atmosphere. CO 2 capture technologies from power plant flue gas include chemical absorption by solvents, physical adsorption on solids, cryogenic separation and selective separation by membranes. Post combustion CO 2 capture by Chemical absorption on amine-based liquids has been available commercially, but is expensive and reduces the efficiency of the power plant. Recently, the adsorption driven technologies have been proposed for CO 2 capture from power plant flue gas at much reduced energy penalty. Adsorbents with high surface areas and tailored surface properties that have been reported for CO 2 capture including zeolites, [1,2,3] activated carbons, [4] carbon molecular sieves, [5] metal organic frameworks (MOFs), [6] pillared clays, aluminum phosphates (ALPOs), and metal oxides, [7,8]. Porous carbon materials are attractive due to their high CO 2 uptake capacity and hydrophobicity but show lower CO 2 -over-N 2 selectivity. Although MOFs show very high CO 2 uptake capacity, most of the reported MOFs show low thermal stability and little CO 2 uptake capacity in the low pressure region that is used for CO 2 separation from flue gas streams. Based on the materials properties required for efficient CO 2 separation from N 2 i.e. high adsorption capacity, CO 2 -over-N 2 selectivity, thermal, chemical and mechanical stability, zeolites are promising for CO 2 separation from power-plant flue gas. Cerium oxide has been used for gases capture in automotive catalytic converters [9] because allow the CO 2 adsorption in the strength distribution and number of basic sites present. Hence the system cerium-Y-zeolite is interesting for CO 2 adsorption. In the present work, Y-zeolites have been modified with cerium by aqueous impregnation using zeolite NaY from Zeolyst International and as precursor of cerium Ce(NO 3 ) 3 .6H 2 O, the percentages are 5, 15 ad 20 %w of cerium. Code samples are nCeNaY, where n=%w of cerium. After impregnation, the samples were dried overnight at 80 °C and calcined at 550°C for 3 h, and then characterized by X-Ray Diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), adsorption/desorption isotherms and Temperature Programed Desorption of CO 2 (CO 2 -TPD). XRD results (figure 1) showed the typical pattern for Y-zeolite in all cases but the intensity of the peaks significantly reduced with cerium addition. There were no peaks related to CeO 2 , which could indicate the ionic interchange of cerium into the zeolite, the good dispersion of CeO 2 or maybe a part of cerium ions were interchanged while the rest were oxidized during calcination. By UV-vis DRS (figure 2) CeO 2 shows a large absorption band around 370 nm due to the charge transfer from O (valence band) to Ce (conduction band). On incorporating small amount of cerium on the zeolite support a band around 290–300 nm is observed in all the Ce-supported zeolites [10]. The adsorption/ desorption isotherms (figure 3) show a type I isotherms for all cases, the modification of NaY zeolite modified the surface and pores, as can be seen in the surface area (As) and pore diameter (Dp) results (table 1). The As of the samples was decreasing at increasing the amount of CeO 2 except the 5Ce/NaY. CO 2 -TPD results (figure 4), indicated new basic sites for samples modified with cerium, which means that CO 2 can be adsorbed by physisorption in the zeolitic structure and probably by chemisorption in the CeO 2 basic sites. [1] Tomita T, Nakayama K, Sakai H. Gas separation characteristics of DDR type zeolite membrane. Micropor. Mesopor. Mater. Vol. 68, (2004) 71–5. [2] Merel J, Clausse M, Meunier F. Carbon dioxide capture by indirect thermal swing adsorption using 13X zeolite. Environ. Prog. Vol. 25, (2006) 327–33. [3] Bonenfant D, Kharoune M, Niquette P, Mimeault M, Hausler R. Advances in principal factors influencing carbon dioxide adsorption on zeolites. Sci. Technol. Adv. Mater. Vol. 9, (2008) 1-7. [4] Page SC, Williamson AG, Mason IG. Carbon capture and storage: fundamental thermodynamics and current technology. En. Pol. Vol. 37, (2009) 14–24. [5] Chen J, Loo LS, Wang K. High pressure CO2 adsorption on polymer derived carbon molecular sieve. J. Chem. Eng. Data.Vol. 53 (2008) 2–4. [6] Yazaydin AO, Benin AI, Faheem SA, Jakubczak P, Low JJ, Willis RR, et al. Enhanced CO 2 adsorption in metal-organic frameworks via occupation of open-metal sites by coordinated water molecules. Chem. Mater. Vol. 21, (2009) 25–30.

Transcript of Abstract Corregido

Page 1: Abstract Corregido

Synthesis, characterization and CO2 capture of Ce supported Y-zeolites

A. A. Camacho a , J. Salmones a, M. A. Valenzuela a, B. Zeifert b, T. Vázquez c, J. L. Contreras c

a Laboratorio de Catálisis y Materiales, ESIQIE IPN, México D. F., 07738, México

b Departamento de Metalurgia, ESIQIE IPN, México D. F., 07738, México

c Universidad Autónoma Metropolitana, Azcapotzalco, CBI Energía, México D. F., 02200, México

Email: [email protected]

Keywords: CO2, zeolites, adsorption, cerium

CO2 capture has been suggested as a possible way to mitigate climate change related to the increasing CO2 concentration in the atmosphere. CO2 capture technologies from power plant flue gas include chemical absorption by solvents, physical adsorption on solids, cryogenic separation and selective separation by membranes. Post combustion CO2

capture by Chemical absorption on amine-based liquids has been available commercially, but is expensive and reduces the efficiency of the power plant. Recently, the adsorption driven technologies have been proposed for CO2 capture from power plant flue gas at much reduced energy penalty. Adsorbents with high surface areas and tailored surface properties that have been reported for CO2 capture including zeolites, [1,2,3] activated carbons, [4] carbon molecular sieves, [5] metal organic frameworks (MOFs), [6] pillared clays, aluminum phosphates (ALPOs), and metal oxides, [7,8]. Porous carbon materials are attractive due to their high CO2

uptake capacity and hydrophobicity but show lower CO2-over-N2

selectivity. Although MOFs show very high CO2 uptake capacity, most of the reported MOFs show low thermal stability and little CO2 uptake capacity in the low pressure region that is used for CO2 separation from flue gas streams. Based on the materials properties required for efficient CO2 separation from N2 i.e. high adsorption capacity, CO2-over-N2

selectivity, thermal, chemical and mechanical stability, zeolites are promising for CO2 separation from power-plant flue gas.Cerium oxide has been used for gases capture in automotive catalytic converters [9] because allow the CO2 adsorption in the strength distribution and number of basic sites present. Hence the system cerium-Y-zeolite is interesting for CO2 adsorption.In the present work, Y-zeolites have been modified with cerium by aqueous impregnation using zeolite NaY from Zeolyst International and as precursor of cerium Ce(NO3)3.6H2O, the percentages are 5, 15 ad 20 %w of cerium. Code samples are nCeNaY, where n=%w of cerium. After impregnation, the samples were dried overnight at 80 °C and calcined at 550°C for 3 h, and then characterized by X-Ray Diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), adsorption/desorption isotherms and Temperature Programed Desorption of CO2 (CO2-TPD).XRD results (figure 1) showed the typical pattern for Y-zeolite in all cases but the intensity of the peaks significantly reduced with cerium addition. There were no peaks related to CeO2, which could indicate the ionic interchange of cerium into the zeolite, the good dispersion of CeO2

or maybe a part of cerium ions were interchanged while the rest were oxidized during calcination.By UV-vis DRS (figure 2) CeO2 shows a large absorption band around 370 nm due to the charge transfer from O (valence band) to Ce (conduction band). On incorporating small amount of cerium on the zeolite support a band around 290–300 nm is observed in all the Ce-supported zeolites [10]. The adsorption/ desorption isotherms (figure 3) show a type I isotherms for all cases, the modification of NaY zeolite modified the surface and pores, as can be seen in the surface area (As) and pore diameter (Dp) results (table 1). The As of the samples was decreasing at increasing the amount of CeO2 except the 5Ce/NaY.CO2-TPD results (figure 4), indicated new basic sites for samples modified with cerium, which means that CO2 can be adsorbed by physisorption in the zeolitic structure and probably by chemisorption in the CeO2 basic sites.

[1] Tomita T, Nakayama K, Sakai H. Gas separation characteristics of DDR type zeolite membrane. Micropor. Mesopor. Mater. Vol. 68, (2004) 71–5.

[2] Merel J, Clausse M, Meunier F. Carbon dioxide capture by indirect thermal swing adsorption using 13X zeolite. Environ. Prog. Vol. 25, (2006) 327–33.

[3] Bonenfant D, Kharoune M, Niquette P, Mimeault M, Hausler R. Advances in principal factors influencing carbon dioxide adsorption on zeolites. Sci. Technol. Adv. Mater. Vol. 9, (2008) 1-7.

[4] Page SC, Williamson AG, Mason IG. Carbon capture and storage: fundamental thermodynamics and current technology. En. Pol. Vol. 37, (2009) 14–24.

[5] Chen J, Loo LS, Wang K. High pressure CO2 adsorption on polymer derived carbon molecular sieve. J. Chem. Eng. Data.Vol. 53 (2008) 2–4.

[6] Yazaydin AO, Benin AI, Faheem SA, Jakubczak P, Low JJ, Willis RR, et al. Enhanced CO2 adsorption in metal-organic frameworks via occupation of open-metal sites by coordinated water molecules. Chem. Mater. Vol. 21, (2009) 25–30.

[7] Deroche I, Gaberova L, Maurin G, Llewellyn P, Castro M, Wright P. Adsorption of carbon dioxide on SAPO STA-7 and ALPO-18: grand canonical ensemble monte carlo simulations and microcalorimetry measurements. Adsorption. Vol. 14, (2008) 7-13.

[8] Yang Q, Lin YS. Kinetics of carbon dioxide sorption on perovskite type metal oxides. Ind. Eng. Chem. Res. Vol. 45, (2006) 2-10.

[9] Bharali, Pankaj, Design of novel nanosized ceria-based multicomponent composites oxides for catalytic applications, Ph.D. Thesis Hyderabad, India, 2011.

[10] J. Krishna Reddy, G. Suresh, C.H. Hymavathi, V. Durga Kumari, M. Subrahmanyam. Cat. Tod. Vol. 141, (2009) 89-93.

Figure 1. DRX of: a) NaY, b) 5Ce/NaY, 15Ce/NaY and

20Ce/NaY

Figure 2. UV-vis of: a) NaY, b) 5Ce/NaY, c) 15Ce/NaY

and 20Ce/NaY

Figure 3. Adsorption/desorption

isotherms of NaY, 5Ce/NaY, 15Ce/NaY and 20Ce/NaY

Figure 4. CO2-TPD of: a) NaY, b) 5Ce/NaY, 15Ce/NaY

and 20Ce/NaY

Table 1. Results of surface area (As) and pore diameter (Dp)Sample As (m2/g) Dp (Å)

NaY 1019.13 15.0065Ce/NaY 868.1007 14.90915Ce/NaY 908.5316 14.89620Ce/NaY 885.7841 14.972