Advances in principal factors influencing carbon dioxide adsorption on zeolites

Abstract

We report the advances in the principal structural and experimental factors that might influence the carbon dioxide (CO 2 ) adsorption on natural and synthetic zeolites. The CO 2 adsorption is principally govern by the inclusion of exchangeable cations (countercations) within the cavities of zeolites, which induce basicity and an electric field, two key parameters for CO 2 adsorption. More specifically, these two parameters vary with diverse factors including the nature, distribution and number of exchangeable cations. The structure of framework also determines CO 2 adsorption on zeolites by influencing the basicity and electric field in their cavities. In fact, the basicity and electric field usually vary inversely with the Si/Al ratio. Furthermore, the CO 2 adsorption might be limited by the size of pores within zeolites and by the carbonates formation during the CO 2 chemisorption. The polarity of molecules adsorbed on zeolites represents a very important factor that influences their interaction with the electric field. The adsorbates that have the most great quadrupole moment such as the CO 2 , might interact strongly with the electric field of zeolites and this favors their adsorption. The pressure, temperature and presence of water seem to be the most important experimental conditions that influence the adsorption of CO 2 . The CO 2 adsorption increases with the gas phase pressure and decreases with the rise of temperature. The presence of water significantly decreases adsorption capacity of cationic zeolites by decreasing strength and heterogeneity of the electric field and by favoring the formation of bicarbonates. The optimization of the zeolites structural characteristics and the experimental conditions might enhance substantially their CO 2 adsorption capacity and thereby might give rise to the excellent adsorbents that may be used to capturing the industrial emissions of CO 2 .

Feasibility of CO2 adsorption by solid adsorbents: a review on low-temperature systems

“…Additionally, CO 2 adsorption capacity increases with the gas phase pressure and decreases with the rise in adsorption temperature. This trend can be observed in Table 4 (Bonenfant et al 2007;Kamiuto et al 2002;Li et al 2013;Yu et al 2012). The study of Siriwardane et al (2003) suggested that natural zeolites with the highest surface area and sodium (Na) content yield the highest adsorption capacity for CO 2 .…”

“…Lower ratio of Si/Al has higher basicity. Basicity increases the specific interaction between CO 2 and zeolites that resulted in high value of CO 2 adsorption (Bonenfant et al 2007;Ertan 2004). The channel diameter of zeolites ranges from 300 to 1000 pm, while kinetic diameter of CO 2 is about 209 pm.…”

Zeolite Rho: a highly selective adsorbent for CO2/CH4separation induced by a structural phase modification

“…20 Zeolites can accomplish those properties and their use in CO 2 /CH 4 separations is based on the preferential adsorption of 30 CO 2 over CH 4 in the polar cavities and channels of relatively aluminium rich zeolites, such as zeolite 13X, Y (FAU) and A (LTA). [21][22][23][24][25][26] However, the high affinity of low Si/Al ratio zeolites for CO 2 hinders its desorption. Then, recently it has been found that for LTA zeolites the optimum Si/Al ratio for 35 CO 2 adsorption/desorption cycles is in the range 5-15.…”

Effectiveness of urea nanofertilizer based aminopropyltrimethoxysilane (APTMS)-zeolite as slow release fertilizer system

“…Silica dissolution will lead to changes in the structure of the zeolite and the decreasing ratio of Si/Al. The decrease of Si/Al ratio may affect the zeolite adsorption capacity and selectivity towards polar molecules such as water vapor (Bonenfant et al, 2008). Figure 1 shows the XRD pattern of the zeolite before and after activation by 1% HF solution.…”