Tuning the structure of N-methyldiethanolamine-based deep eutectic solvents for efficient and reversible SO2 capture

Abstract

Three cheap DESs comprising of N-methyldiethanolamine (MDEA) and imidazole (Im), 1,2,4-triazole, and tetrazole were investigated for capturing SO₂ at low concentrations. Surprisingly, with the addition of Im, the SO₂ absorption capacity and desorption efficiency were improved. Spectroscopic analysis and quantum chemical calculations confirmed that MDEA–Im effectively and reversibly captured SO₂ through the hydrogen bond network and synergistic action between MDEA and Im.