Capture of CO₂ from exhaust gas using yeontan waste supporting monoethanolamine adsorbent

To achieve efficient CO₂ capture from industrial exhaust gases and enhance the resource utilization value of honeycomb coal slag, this study developed a composite adsorbent using yeontan waste as a carrier and monoethanolamine （MEA） as the active component. A composite adsorption system was constructed by loading 75% MEA solution onto 65-mesh（0.21 mm） coal slag powder. The surface morphology, elemental composition, mineral structure, and functional groups of the adsorbent were characterized by SEM, EDS, XRD, and FTIR. Using a self-designed fixed-bed reactor, the effects of gas flow rate （0.23−5.00 L/min） and CO₂ concentration （400×10⁻⁶−2 000 ×10⁻⁶） on the capture performance were systematically investigated. The cyclic stability was evaluated through thermal regeneration, and practical validation was conducted using real vehicle exhaust （containing NO_x/SO₂）. The results showed that under conditions of 5.00 L/min flow rate and nearly 2000×10⁻⁶ CO₂ concentration, the instantaneous capture efficiency reached 86.3%. The maximum capture capacity of 1 mL of MEA solution is 0.04 L of CO₂ under standard conditions. Under thermal regeneration at 145 ℃, the CO₂ desorption efficiency for simulated flue gas reached 97.9%, and the capture capacity retention rate remained at 70% after 15 cycles. In the real vehicle exhaust test, the CO₂ capture capacity reached 0.96 L CO₂ with a single-cycle desorption rate of 90.7%. This study innovatively proposes a low-cost technology for the capture and utilization of CO₂ from exhaust gases.