Direct Air Capture of CO₂ with Metal Nitrate-Doped, Tetraethylenepentamine-Functionalized SBA-15 Adsorbents

Abstract

Direct air capture (DAC) by solid amine adsorbents is a promising route to mitigate CO2 emissions from distributed sources and confined spaces. However, a capacity–stability trade-off of supported amine adsorbents often exists for DAC applications. Herein, we report that a KNO3-doped, tetraethylenepentamine (TEPA)-functionalized SBA-15 adsorbent (i.e., 50TEPA-4.5K/SBA-15) has a high CO2 adsorption capacity and good cycling stability for DAC. 50TEPA-4.5K/SBA-15 is synthesized by successive impregnation of KNO3 (4.5 wt %) and TEPA (50 wt %) onto SBA-15 and evaluated using a fixed-bed adsorber in cyclic operation (adsorption at 30 °C in 440 ppm of CO2 and 50% relative humidity and desorption at 90 °C in pure N2). 50TEPA-4.5K/SBA-15 possesses good antioxidation properties; moreover, its CO2 adsorption capacity stabilizes at 5.45 mmolCO2 /gadsorbent in 10 consecutive adsorption–desorption cycles, which is much higher than that of 50TEPA/SBA-15 (3.64 mmolCO2 /gadsorbent) and also outperforms that of TEPA-functionalized adsorbents in the literature. This study provides new opportunities to develop high-performance solid amine adsorbents for DAC applications.

Metal ion-supported mesoporous silica materials for the removal of sulfamethizole from water

“…26,27 In recent years, metal-doped SBA-15 porous materials have been widely applied as ideal adsorbents in the removal of different pollutants, such as metal ions in wastewater, sulfur and nitrogen compounds in oil, small organic molecules and CO 2 . [28][29][30][31] It has advantages such as stability, good dispersibility in water, and good recovery performance. However, metal-doped SBA-15 has been rarely used to remove SAs.…”