“Low Cost” Pore Expanded SBA-15 Functionalized with Amine Groups Applied to CO2 Adsorption

Abstract

The CO2 adsorption capacity of different functionalized mesoporous silicas of the SBA-15 type was investigated and the influence of textural properties and the effect of the silicon source on the CO2 uptake studied. Several adsorbents based on SBA-15 were synthesized using sodium silicate as silicon source, replacing the commonly used tetraethyl orthosilicate (TEOS). Thus, we synthesized three couples of supports, two at room temperature (RT, RT-F), two hydrothermal (HT, HT-F) and two hydrothermal with addition of swelling agent (1,3,5-triisopropylbenzene) (TiPB, TiPB-F). Within each couple, one of the materials was synthesized with ammonium fluoride (NH4F). The supports were functionalized via grafting 3-aminopropyltriethoxysilane (APTES) and via impregnation with polyethylenimine ethylenediamine branched (PEI). The adsorption behavior of the pure materials was described well by the Langmuir model, whereas for the amine-silicas, a Dualsite Langmuir model was applied, which allowed us to qualify and quantify two different adsorption sites. Among the materials synthesized, only the SBA-15 synthesized at room temperatures (RT) improved its properties as an adsorbent with the addition of fluoride when the silicas were functionalized with APTES. The most promising result was the TiPB-F/50PEI silica which at 75 °C and 1 bar CO2 captured 2.21 mmol/g.

Evaluation of porous clay heterostructures modified with amine species as adsorbent for the CO2 capture

“…However, this technique displays several drawbacks related to the high energy consumption required for their regeneration and the high evaporation of the amine species due to their low thermal stability, which causes corrosion of equipment and the loss of effectiveness along the time [3,4]. In the last decade, the use of porous materials, such as zeolites [5][6][7], carbons [8,9], metal organic frameworks (MOF) [10,11], metal oxides [12,13], layered double hydroxides (LDH) [14,15] or porous silicas [4,[16][17][18][19] have shown to be an alternative to the aqueous alkylamine solutions for the selective CO 2 capture. These materials can be used as molecular sieves with narrow pore size, which favors the specific solid-gas interactions.…”

CO2 Adsorption of Materials Synthesized from Clay Minerals: A Review

“…The design of homogeneous porous silica has been developed in the last 25 years. Many scientific groups have synthesized several porous silicas with different porosity and morphology such as MCM-41, MCM-48, SBA-15, HMS or mesocellular foams [12][13][14][15][16]. In all cases, the CO 2 adsorption capacity is directly related to the microporosity of the synthesized porous silica, although the CO 2 adsorption capacity is limited compared to the structure of the MOFs [2].…”

Natural and Modified Montmorillonite Clays as Catalysts for Synthesis of Biolubricants

“…However, the bands located at 520 and 460 cm −1 , ascribed to Si–O–Al and Si–O–Si bending vibration modes, hardly suffer modifications after the acid treatment [ 33 ]. Finally, the band located at about 1640 cm −1 is assigned to H–O–H bending vibration [ 36 ]. In the case of the FTIR spectrum of the PILC sample, the intensities of Si–O–Al and Mg–O–Al mode vibrations decrease, even these bands disappear, while the Al–O– bands are maintained.…”