A highly effective and low-cost sepiolite-based solid amine adsorbent for CO2 capture in post-combustion

Abstract

Post-combustion carbon dioxide capture using inexpensive and highly efficient materials is a powerful tool for lowering industrial CO2 emissions. Herein, by impregnating acid-modified sepiolite with pentaethylenehexamine (PEHA), a series of adsorbents were delivered. For the comprehensive study of the adsorbents, the textural properties, saturation adsorption experiment, breakthrough adsorption experiment, kinetic models, reaction mechanism, economic evaluation, cyclic and thermal stability were measured. The results exhibited that the optimal H-P-0.9 adsorbent demonstrated a adsorption capacity of 2.47 mmol/g at 50 °C with good regeneration. Considering application to capture CO2 in flue gas, breakthrough adsorption experiments were studied, a higher adsorption capacity of 2.94 mmol/g at 50 °C (with 5% H2O) appeared in contrast to other sepiolite sorbents. The main factors of CO2 capture process were chemisorption and physisorption by Avrami model. Furthermore, appropriate moisture promoted the CO2 capture performance of the adsorbent. In addition, the result of in-situ DRIFTs revealed the capture process follows the anion cation mechanism, CO2 was finally converted to carbamate. The economic evaluation showed that the adsorbent capture 1 t CO2 at a low price of 2.0 × 105 $. These results proved that the sepiolite-based adsorbent may be a potential material for CO2 capture with low price and excellent adsorption capacity.