Advancing energy-efficient CO₂ desorption from amine solvent using SO₄^2-/ZrO₂ catalytic membrane contactor under falling film evaporation

CO₂ capture using amines holds promise for emission reduction, however, it faces critical energy penalties during solvent regeneration >120 °C. Herein, we propose a novel strategy for boosting 30 wt% monoethanolamine (MEA) regeneration below 100 °C, by immobilizing a sulfated zirconia (SO₄^2-/ZrO₂) catalyst on a tubular ceramic membrane substrate, as opposed to conventional particulate supports. This design, which seamlessly combines catalytic dissociation (for accelerated MEA-CO₂ breakdown) and intensified mass transfer (leveraging falling film evaporation for CO₂ release), achieves synergistic efficiency gains in low-temperature regeneration. Combined characterization and density functional theory (DFT) calculations confirmed that SO₄^2-/ZrO₂ species strongly anchored on the Al₂O₃ substrate due to electron transfer between Zr and O, creating Brønsted and Lewis acid sites. These structural features enabled the catalytic membrane to achieve a desorption flux of 16.85 mol/(m²·h) (41.8 % higher than non-catalytic membranes) at energy consumption of 31.8 kJ/mol CO₂ (38.2 % reduction vs. conventional thermal desorption). It retained 97 % of desorption flux without detectable acid-catalyst leaching over 10 desorption cycles. DFT calculations reveal that ZrO₂-SO₄^2--H acid sites act as “proton pumps”, lowering the energy barrier of MEA-CO₂ dissociation. The catalytic mechanism was further clarified by correlating various acid site configurations with reaction energy barriers. This approach offers a scalable platform for energy-efficient amine regeneration, advancing CO₂ capture systems.