Acid-treated activated carbon as simple and inexpensive catalyst to accelerate CO2 desorption from aqueous amine solution

Abstract

Catalytic amine regeneration has emerged as a promising technique for accelerating CO2 desorption from aqueous amine solutions at temperatures ≤ 100 ⁰C, to ultimately reduce the thermal penalty of CO2 capture process. However, the development of abundant and inexpensive materials is imperative. Herein, we prepared superabundant and low-cost activated carbon (AC) catalysts by activating AC with two acidic solutions, sulfuric acid (H2SO4) and phosphoric acid (H3PO4), and investigated their catalytic performance in the process of amine regeneration at a temperature of 86 °C. The experimental results revealed that the prepared catalysts are highly effective in amine regeneration process and can significantly increase the CO2 desorption rate and desorbed CO2 quantity at temperatures as low as 60 °C. Catalyst characterization data shows that the prepared catalysts have a higher surface area and acidity, together both of which can accelerate the CO2 desorption at much lower temperatures to ultimately reduce the regeneration heat duty by ∼20%. The prepared catalysts can easily be separated and reused in cyclic experiments, showcasing their potential use in a continuous CO2 capture unit. This study demonstrates the use of inexpensive materials to optimize the CO2 desorption process, ultimately leading to the development of a green CO2 capture process.

Keywords

• Catalytic amine regeneration
• Activated carbon
• Regeneration heat duty
• Co2 capture
• Catalyst stability