Efficient Carbon Dioxide Capture Using a Novel Biphasic DETA–DMCA Solvent System: CO ₂ Absorption and Phase Separation Performance

ABSTRACT The urgent need to mitigate CO 2 emissions from fossil‐based industries necessitates the development of CO 2 separation solvents that combine high absorption capacity with low regeneration energy. The conventional monoethanolamine (MEA) solvent is widely used but limited by high regeneration energy constraint, equipment corrosion, and degradation. In this work, a novel biphasic solvent system comprising diethylenetriamine (DETA) and dimethylcyclohexylamine (DMCA) was proposed and thoroughly evaluated for post‐combustion CO 2 capture. The optimized formulation (DMCA:DETA = 3:2) achieved a high CO 2 loading capacity of ∼1.1 mol CO 2 /mol amine with spontaneous phase separation, producing a 70% CO 2 ‐rich phase. Selective regeneration of this rich phase reduced the total energy demand to 2.76 GJ/t CO 2 , representing ∼40% savings compared with 5 M MEA (4.34 GJ/t CO 2 ). Kinetic studies confirmed rapid absorption rates, whereas FTIR analysis demonstrated reversible carbamate formation and solvent stability across multiple absorption–desorption cycles. The reduced viscosity of the CO 2 ‐rich phase further improved prospects for the chosen solvent. These outcomes established the DETA–DMCA biphasic system as a durable, energy‐efficient, and scalable solvent for next‐generation CO 2 capture, offering significant potential for deployment in industrial flue gas treatment.