A regenerable adsorbent for CO2 enrichment working between 110°C and 150°C

Abstract

A temperature-tolerance adsorbent is a necessary for CO₂ enrichment from flue gas since most adsorptive performances are sensitive to the temperature. In this work, Mg and tetraethylenepentaamine (TEPA) co-modified SSZ enriches CO₂ at 110 °C. The adsorption capacity is 2.01 mmol·g⁻¹ at 110 °C and the highest enrichment efficiency stably maintains at 3 under a desorption space velocity of 50 mL·min⁻¹·g⁻¹ at 150 °C. A detailed spectroscopic investigation reveals the advantage of this adsorbent over others. Primary and secondary amines of TEPA together with Mg form a regenerable network, which supplies adsorptive sites for CO₂. This process is characterized by forming NCOO⁻ and NH₃⁺ groups, which is accompanied by a proton transfer from the Mg-N bond amine to the neighboring free amine. In comparison to adsorbents in similar reports, the adsorbent has the advantage of owning enough adsorptive capacity, slow attenuation rate, and high work temperature at the same time.