Nonaqueous amine-based blends have great potential for energy-efficient CO 2 absorbent. In this work, densities and viscosities were measured for liquid binary mixtures of 2-(ethylamino)ethanol (EAE) and 2-(butylamino)ethanol (BAE) with 2-butoxyethanol (EGBE) at temperatures of (293.15–353.15)K over the entire concentration range and atmospheric pressure. Intermolecular interactions between EGBE and two secondary amines with different carbon chain length were discussed. The excess molar volume ( V E ), viscosity deviations ( ∆η ) and excess Gibbs free energy ( ∆G ⁎ E ) were calculated from the experimental data and also correlated with the Redlich-Kister equation to estimate the binary interaction parameters. The experimental data and the calculated from the proposed correlations for the studied binary mixtures matched well each other, with AADs within 0.01% and 1.45% for density and viscosity respectively. The variation of excess properties was also discussed in terms of intermolecular interactions. Weak interactions on mixing these binary mixtures with different mass fractions were observed from the FTIR spectra analysis.
Solubilities of SO 2 have been determined in four biobased solvents (BBSs) at temperatures between 293.15 K and 323.15 K with 10 K intervals and pressure scope of (0–120.0) kPa using isochoric saturation method. The BBSs were selected from butyl lactate (BL), glyceryl triacetate (GT), triethyl citrate (TEC), and acetyl triethyl citrate (ATEC). Henry’s constants and thermodynamic properties such as Gibbs free energy , enthalpy and entropy of dissolution were derived from the solubility data. The gravimetric solubilities of SO 2 in BBSs were in the range of (0.07–8.52) mol.kg −1 and changed with the sequence of GT > BL > TEC ≈ ATEC. All the dissolution enthalpies were negative at each condition. The performances of SO 2 absorption in these solvents were further compared with those in some ionic liquids as well as common absorbents. The results illustrated that present BBSs possessed the potentiality as SO 2 absorbents due to their relatively large absorption ability, small absorption enthalpy, low toxicity, and biodegradability.
Dongshun Deng,Bao Gao,Chao Zhang,Xiuzhi Duan,Yanhong Cui,Jingheng Ning
Ammonia (NH 3 ) is not only a harmful gas to environmental problem, but also a fundamental raw material in chemical industry. The effective separation and recovery of NH 3 from exhaust gas at low cost still remains a challenge for a long time. In this study, a new strategy to construct protic deep eutectic solvents (DESs) by paring NH 4 SCN as hydrogen-bond acceptor with various hydrogen-bond donors [glycerol (G), ethylene glycol (EG), urea (U), acetamide (AT), and caprolactam (CL)] was proposed for efficient and reversible absorption of NH 3 . Results showed that all the DESs possessed exceptional NH 3 absorption capacity and high NH 3 /CO 2 selectivity. At 303 K and 0.10 MPa, the absorption capacity of NH 3 in NH 4 SCN-glycerol (2:3) is as high as 0.223 g NH 3 per g DES, which is much higher than all reported functional ILs and DESs up to date. The NH 3 saturated DES was easily regenerated and recycled 25 times with persistent absorption performance. The influences of DES composition, temperature, NH 3 partial pressure on NH 3 absorption performance were also explored in detail. The absorption mechanism was analyzed using NMR spectroscopy and quantum calculation. These protic NH 4 SCN-based DESs presented as promising absorbents for NH 3 because of their high absorption capacity and good reversibility.