N2 and CO2 Adsorption by Soils with High Kaolinite Content from San Juan Amecac, Puebla, México

Abstract

Carbon dioxide (CO 2 ) is considered one of the most important greenhouse gases in the study of climate change. CO 2 adsorption was studied using the gas chromatography technique, while the Freundlich and Langmuir adsorption models were employed for processing isotherm data in the temperature range of 473-573 K. The isosteric heat of adsorption was calculated from the Clausius-Clapeyron equation. Moreover, the thermodynamic properties ∆G, ∆U, and ∆S were evaluated from the adsorption isotherms of Langmuir using the Van't Hoff Equation. The four soil samples were recollected from San Juan Amecac, Puebla, Mexico, and their morphologies were investigated through X-ray diffraction (XRD) and N 2 adsorption at 77 K. The SJA4 soil has a crystalline Kaolinite phase, which is one of its non-metallic raw materials, and N 2 isotherms allowed for the determination of pore size distributions and specific surface areas of soil samples. The Barrett-Joyner-Halenda (BJH) distribution of pore diameters was bimodal with peaks at 1.04 and 3.7 nm, respectively. CO 2 adsorption showed that the SJA1 soil afforded a higher amount of adsorbed CO 2 in the temperature range from 453 to 573 K followed by SJA4 and finally SJA2, classifying this process as exothermic physisorption.

Critical Admission Temperature of H2 and CH4 in Nanopores of Exchanged ERI Zeolites

“…This value, also called isostatic enthalpy of adsorption, represents the energy of interaction between the zeolite and the adsorbed gases. This equation assumes the adsorbate behaves as an ideal gas and the molar volume of the adsorbed phase is minimal compared to that of the adsorbate [31].…”

Nanoporosity and Isosteric Enthalpy of Adsorption of CH4, H2, and CO2 on Natural Chabazite and Exchanged

“…Figure 2 shows the diffraction patterns of the zeolites under study. The powder patterns were analyzed according to the Rietveld method [26], using the High Score Plus 3.0 software [27]. Crystalline phases were identified using the database of the International Centre for Diffraction Data for Inorganic Substances (Inorganic Crystal Structure Database).…”

Effect of Intercalation Agents on Morphology of Exfoliated Kaolinite

“…To prepare the kaolinite/quaternary ammonium salts intercalation compounds (K-Qas), approximately 1 g of methoxy-modified kaolinite was added into a 20 mL of 1 mol/L solution of quaternary ammonium salts in methanol and stirred under room temperature for 72 h. The precipitations were centrifuged and the excess quaternary ammonium salt was removed by washing six times with fresh ethanol. Then the resulting products were dried at 80 • C for 24 h. The dried products were denoted as K-Qa-C n (n = 4,6,8,10,12,14,16,18). To prepare the kaolinite/fatty acid intercalation compounds (K-Fas), a 1 mol/L solution of fatty acid in water was prepared at 80 • C firstly; 2 g of wet methoxy-modified kaolinite was added into 20 mL of the prepared solution and stirred for 72 h at the same temperature.…”

“…Kaolinite is a widely studied and applied class of phyllosilicate minerals [1][2][3][4][5][6]. Because of its specific physical and chemical properties, it has been used as a pigment for coatings, a filler for paper and polymers, an extender for water-based paints and inks, and a major component of ceramics [7][8][9][10][11].…”