CO₂ Sorption on Mesoporous Solids: Effect of Temperature and Water Content

Abstract

CO2 captured by solid adsorbents is considered one of the promising technologies for carbon capture and sequestration. The sorption equilibria of CO2 on commercial CO2 adsorbents (silica gel and Norit SX2) and synthesized CaO were measured experimentally by using a volumetric method in a temperature range of 0–8 °C, at which CO2 hydrate is stable to form. The CO2 uptake increases with decreasing temperature in silica gel and Norit SX2 on a dry basis; differs in CaO as the adsorption rate of CO2 in calcium-based sorbent is high at higher temperatures. The effect of water content on the samples studied was measured at a temperature of 2 °C on a wet basis. The highest CO2 amount adsorbed was obtained at the lowest value of water ratio studied (R w = 0.03), which is close to CO2 sorption in a dry basis. However, the adsorption capacities on wet synthesized CaO were water-content dependent, of which the highest sorption capacity was obtained at a particular isotherm with a water ratio of 0.67. It can be concluded that CaO has the ability to be further utilized for CO2 separation in the presence of a minute quantity of water.

Thermal Decomposition of Biomineralized Calcium Carbonate: Correlation between the Thermal Behavior and Structural Characteristics of Avian Eggshell

“…CO 2 capture and storage by means of reversible solid–gas reactions have been studied as a potential method for reducing anthropogenic CO 2 and mitigating the greenhouse effect. − As such, alkaline and alkaline earth oxides and hydroxides have long been studied as potential CO 2 adsorbents. − Among other processes, CaO carbonation to form CaCO 3 and thermal decomposition of the CaCO 3 to reproduce CaO are the most extensively studied processes in terms of reaction kinetics, thermodynamics, and morphology: CaO (s) + CO 2 (g) ⇄ CaCO 3 (s). − Both the carbonation of CaO and the thermal decomposition of CaCO 3 are complex heterogeneous processes that are controlled by various physico-geometrical processes and reaction conditions including the partial pressure of CO 2 . The formation of surface product layers of CaCO 3 and CaO during carbonation and decomposition processes, respectively, is the most characteristic physico-geometrical factor controlling the heterogeneous kinetics, and it is generally seen for the reactions in solid–gas systems. − Because the diffusion of CO 2 through surface product layers is necessary for CO 2 intake and uptake, complete formation of CaCO 3 through the carbonation of CaO cannot be achieved in many cases due to the blocking of CO 2 diffusion by the surface product layer. , In addition, deterioration of the CO 2 absorption capacity is generally observed with repeated carbonation–decarbonation cycles .…”

CO2 Sorption Properties over Ordered Mesoporous Carbon CMK-3 in the Presence of MDEA Solution

“…modified activated carbon using three different amines (DEA, MDEA, and TEPA), with the highest CO 2 sorption capacity being 5.63 mmolCO 2 /g adsorbent. Gas hydrates can be utilized in the field of carbon dioxide capture and storage. , Sun et al noted that the CO 2 sorption capacity in the presence of water reaches 1.5 times as much as that of dry carbon. Zhou et al investigated the CO 2 storage of CMK-3 in the presence of pure water, and 42 mmol/g was adsorbed at 275 K and 3.6 MPa when the mass ratio of water to dry carbon was 2.35.…”