CO2 sorption in wet ordered mesoporous silica kit-6: effects of water content and mechanism on enhanced sorption capacity

Abstract

The sorption isotherms of CO 2 in wet ordered mesoporous silica KIT-6 with different amounts of pre-adsorbed water were firstly collected experimentally using a volumetric method in the temperature range of 275-281 K. The isotherms show an inflection point indicating CO 2 hydrates form in the pore spaces which is proofed by the enthalpy change calculated at the inflection pressure, and the quantity of water content shows considerable effect on the sorption capacity of CO 2 . The highest enhancement of sorption capacity in the presence of water is observed in wet KIT-6 sample with water loadings of 2.48, which is about 12.80 mmol/g and 1.86 times than that on dry sample. However, the saturation capacity is still far less than that what can be stored merely in the form of hydrates due to the low ratio of water utilization because of the large pore and the polar surface of KIT-6.

APTES grafted ordered mesoporous silica KIT-6 for CO2 adsorption

“…CCS is important to mitigate the global warming and its consequences by capture of CO 2 from large anthropogenic sources. Aqueous alkanolamines and chilled ammonia based absorption process [5,6], membrane separation process [7,8], novel cryogenic process [9], algal biomass process [10,11] and porous solid adsorption process [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] are most commonly used for CO 2 capture. Among these processes aqueous alkanolamine especially monoethanolamine (MEA) and diethanolamine (DEA) based absorption process is well known with significant commercial application for CO 2 capture.…”

Sorption equilibria of CO2 on synthesized CaO in the presence of water

“…Since each isotherm starts at a pressure reading of zero, it is necessary to place the system in a vacuum [17]. Thus, the wet sample was cooled to -20°C for 4 h to minimize the loss of water due to vaporization [18]. Then, the temperature of the chamber was raised to the specified value before sorption measurement was started [5].…”

“…1, it can be observed that the hydrate is started to form at pressure around 25 bar for curves 4 and the hydrate formation pressure increases for curves 2 and 3. The phenomenon may due to insufficient amount of pre-adsorbed water to trap CO 2 molecules for formation of CO 2 hydrate in which only the smaller pores are firstly filled with water [18]. When hydrate is formed in small pores, very high excess Gibbs free energies is produced on the surface and required higher formation pressure [18].…”

“…The phenomenon may due to insufficient amount of pre-adsorbed water to trap CO 2 molecules for formation of CO 2 hydrate in which only the smaller pores are firstly filled with water [18]. When hydrate is formed in small pores, very high excess Gibbs free energies is produced on the surface and required higher formation pressure [18]. It is apparent that the lower CO 2 capture capacities by CaO are obtained when there too much water content (curves 6, 7 and 8) as illustrated in Fig.…”

Adsorption of Carbon Dioxide by Reusing Drinking Water Treatment Plant Sludge

“…They have gained attention in recent years [3] as the concentration of CO2 increases from 278 ppm to about 405 ppm from 1970 to 2017 as measured by Global Monitoring Division of NOAA/Earth System Research Laboratory [4]. Various CO2 removal methods such as absorption [5][6][7], membrane separation [8,9], cryogenic distillation [10] and adsorption [11][12][13][14][15] have been developed. Among these techniques, an adsorption technique received great attention due to its highly energy efficient and several other competitive advantages [3,16,17].…”