Improving CO2 desorption performance in monoethanolamine solutions by adding titanium pyrophosphate catalyst

Catalytic CO₂ desorption has emerged as a crucial strategy for enhancing the efficiency of CO₂ capture and reducing energy requirements, thereby advancing chemical absorption methods. This study examines the catalytic effectiveness of titanium pyrophosphate (TiP₂O₇) in improving monoethanolamine (MEA)-based CO₂ absorption and desorption processes, comparing its performance with other titanium-based catalysts, including titanium dioxide (TiO₂), titanium tetrahydroxide (TiO(OH)₂), and titanium carbide (TiC). In TiP₂O₇, Ti ions function as Lewis acid sites by accepting electron pairs (LASs), P₂O₇^4- anions act as proton carriers, facilitating rapid proton transfer as Lewis base sites (LBSs), and active hydroxyl groups on the surface, resulting from water molecule dissociation or the deprotonation reaction, function as Brönsted acid sites (BASs). These sites work synergistically to accelerate CO₂ desorption. TiP₂O₇ outperforms the other catalysts tested, primarily due to its optimal Brönsted/Lewis (B/L) ratio. This characteristic is particularly advantageous for regenerating RNHCOO^-, as the reaction predominantly follows a hydrogen transfer pathway facilitated by the BASs. Consequently, TiP₂O₇ enhances the CO₂ desorption rate by 41.5% at a desorption temperature of 91 °C, while simultaneously reducing the relative heat duty by 13% compared to processes without catalysts.