Interaction of Water with Alkali-Metal Cation-Exchanged X Type Zeolites:  A Temperature-Programmed Desorption (TPD) and X-ray Diffraction Study†

Langmuir ◽  
1999 ◽  
Vol 15 (18) ◽  
pp. 5937-5941 ◽  
Author(s):  
B. Hunger ◽  
O. Klepel ◽  
C. Kirschhock ◽  
M. Heuchel ◽  
H. Toufar ◽  
...  
2015 ◽  
Vol 25 (3) ◽  
pp. 25-34 ◽  
Author(s):  
Laura Alicia Ramírez Llamas ◽  
Araceli Jacobo Azuara ◽  
J. Merced Martínez Rosales

In this paper, layered double hydroxides (LDH) were synthesized and characterized using techniques of Physisorption of Nitrogen, Infrared, Temperature Programmed Desorption, X-Ray Diffraction, TGA and Immersion Microcalorimetry, in order to determine the basic properties of the adsorbent. The methyl orange (MO) is used as a dye and as a result, it is frequently found in effluents from textile industries. The dye adsorption isotherms on LDH were studied as function of pH and temperature. The maximum adsorption capacity of methyl orange on LDH was carried out at pH 5, and the minimum adsorption capacity at pH 11, being 40.2 mg/g and 22.1 mg/g, respectively. Furthermore, the suitable temperature to promote the adsorption of methyl orange on LDH was at 25 °C, as at 35 °C shows a significant decrease. 


Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 807
Author(s):  
Zen Maeno ◽  
Xiaopeng Wu ◽  
Shunsaku Yasumura ◽  
Takashi Toyao ◽  
Yasuharu Kanda ◽  
...  

In this study, the characterization of In-exchanged CHA zeolite (In-CHA (SiO2/Al2O3 = 22.3)) was conducted by in-situ X-ray diffraction (XRD) and ammonia temperature-programmed desorption (NH3-TPD). We also prepared other In-exchanged zeolites with different zeolite structures (In-MFI (SiO2/Al2O3 = 22.3), In-MOR (SiO2/Al2O3 = 20), and In-BEA (SiO2/Al2O3 = 25)) and different SiO2/Al2O3 ratios (In-CHA(Al-rich) (SiO2/Al2O3 = 13.7)). Their catalytic activities in nonoxidative ethane dehydrogenation were compared. Among the tested catalysts, In-CHA(Al-rich) provided the highest conversion. From kinetic experiments and in-situ Fourier transform infrared (FTIR) spectroscopy, [InH2]+ ions are formed regardless of SiO2/Al2O3 ratio, serving as the active sites.


1999 ◽  
Vol 590 ◽  
Author(s):  
Andrea Freitag ◽  
J. A. Rodriguez ◽  
J. Z. Larese

ABSTRACTHigh resolution adsorption isotherms, temperature programmed desorption (TPD), x-ray diffraction (XRD) and x-ray absorption near edge spectroscopy (XANES) methods were used to investigate the interaction of SO2 with high quality MgO powders. The results of these investigations indicate that when SO2 is deposited on MgO in monolayer quantities at temperatures near 100K both SO3 and SO4 species form that are not removed by simply pumping on the pre-dosed samples at room temperature. TPD and XANES studies indicate that heating of pre-dosed MgO samples to temperatures above 350 °C is required for full removal of the SO3/SO4 species. XANES measurements made as a function of film thickness indicate for coverages near monolayer completion that the SO4 species form first.


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