Amine-Modified Mesoporous Silica for CO₂ Adsorption: The Role of Structural Parameters

Abstract

The present study investigated the role of structural parameters such as pore size, pore volume, and specific surface area of mesoporous silica on the CO2 sorption performance of various amine-functionalized adsorbents. A series of mesoporous silica with different structural properties KIT-6, MCM-41, SBA-15, and HV MCM-41 were synthesized and functionalized with pentaethylenehexamine (PEHA) by wet impregnation. The CO2 sorption performances of the sorbents were evaluated using high pressure gas adsorption analyzer. The sorption capacity of adsorbents follows the order: MCM-41 < HV MCM-41 < SBA-15 ≈ KIT-6 at 105 °C and 1 bar. Larger pore size reduces the mass transfer resistance, and large pore volume improves the PEHA distribution inside the pores. The high specific surface area has little impact during adsorption. Due to the 3D structure with interconnected pores, KIT-6 shows the lowest heat of regeneration (57.8 kJ/mol CO2) during adsorption. The PEHA-impregnated KIT-6 (K-60 PEHA) shows the highest sorption capacity 4.48 mol CO2/g at 105 °C and 1 bar. It also exhibit fairly stable sorption performance up to 10 adsorption/desorption cycles between in the temperature range of 90–105 °C.

Piperazine‐modified activated alumina as a novel promising candidate for CO2 capture: experimental and modeling

“…This means that piperazine was loaded into the pores of activated alumina, and the pores were filled with piperazine. In fact, surface modification reduces pore space, which causes a change in specific surface area and the specific volume of the pores . The isotherm of gas adsorption was also in accordance with type 4, which was consistent with the IUPAC classification for mesoporous materials.…”

“…In fact, surface modification reduces pore space, which causes a change in specific surface area and the specific volume of the pores. 46 The isotherm of gas adsorption was also in accordance with type 4, which was consistent with the IUPAC classification for mesoporous materials. Fourier transform infrared spectroscopy is used to determine the functional groups in the adsorbents.…”

Sorbents for the Direct Capture of CO2 from Ambient Air

“…[219] capture.They inferred that alarge pore size or high intrawall pore volume of the support improve the adsorptive properties through enhanced amine accessibility.S upports with large pores also allowed ah igher density of amine groups on the surface to be achieved because of reduced steric hindrance between the grafted triamine species.Arecent study also investigated the role of structural parameters such as pore size,p ore volume,a nd specific surface area of mesoporous silica on the CO 2 sorption performance of various aminefunctionalized sorbents. [223] Theg eneration of monolithic structures formation from aminosilica by an ovel threedimensional (3D) printing method could facilitate the development of amine-grafted silica CO 2 sorbents on practical contactors. [224] Theg roups of Fayaz [225] and Lashaki et al [226] studied the effect of steam exposure on the CO 2 capture performance of amine-grafted silica.…”

A review of N-functionalized solid adsorbents for post-combustion CO2 capture

“…Kishor et al [81] investigated how the long-term stability of amine-loaded silica related to storage time. Even after 6 months, the adsorption capacity of PEHA-loaded KIT-6 was undiminished.…”