A Low-Viscosity Absorbent with Low Regeneration Energy Consumption for Efficient NH3 Separation

Abstract Triazolium-based ionic liquids (ILs) have attracted considerable attention due to their excellent ammonia (NH3) absorption properties. However, they are typically solid at room temperature, which limits their direct application in conventional scrubbing processes. To address this limitation, this study designed a series of low-viscosity deep eutectic solvents (DESs) for NH3 absorption. Experimental results show that the [1,2,3-TrizH2][NO3]2/EG (1:5) DES absorbs up to 0.256 g NH3/g DES at 303.15 K and 1 bar, outperforming most previously reported DESs in absorption capacity, with a viscosity of only 17.8 mPa·s and a volumetric mass-transfer coefficient of up to 0.130 min–1. More importantly, its regeneration energy consumption is as low as 0.586 GJ/t NH3─51.9% lower than that of the parent IL, thereby offering dual advantages of high absorption efficiency and low regeneration energy demand. This work provides a new idea for the development of NH3 absorption solvents that have both high absorption capacity and low energy consumption.