Deep eutectic solvents (DESs) have emerged as promising alternative candidates for CO2 capture in recent years. In this work, several novel DESs were firstly prepared to enhance CO2 absorption. Structural and physical properties of DESs were investigated, as well as their absorption performance of CO2. A distinct depression in the melting point up to 80 K of DESs was observed compared with that of BMIMCl. The observed red shifts of the C2H group in an imidazolium ring and its chemical shifts downfield in NMR spectra are indicative of a hydrogen bond interaction between BMIMCl and MEA. In particular, CO2 uptake in MEA : ILs (4 : 1) at room temperature and atmospheric pressure is up to 21.4 wt%, which is higher than that of 30 wt% MEA (13%). A hydrogen bond related mechanism was proposed in which ILs act as a medium to improve CO2 uptake through hydrogen bonds. Finally, the firstly reported overall heat of CO2 absorption is slightly higher than that of 30 wt% MEA, implying that the hydrogen bonds of DESs contribute to the overall heat of CO2 absorption. This study reveals that the heat of CO2 absorption can be tailored by the proper molar ratio of MEA and ILs.

A lab amine-based chemical absorption pilot plant for CO 2 capture from coal-fired power plants was built. The character of CO 2 capture of the new blended amine absorbent was studied in the pilot plant, under the condition of prolonged operation. Three campaigns were conducted. One campaign was the baseline experiment to evaluate the cyclic absorption and desorption character of the absorbent during 500 h with 12 vol % CO 2 and 18 vol % O 2 . Other two campaigns were performed to evaluate the influence of SO 2 on the absorption character of the absorbent, with 214 and 317 ppm SO 2 , respectively. The CO 2 reaction rate and mass transfer behavior were analyzed for the three campaigns. The results show that the CO 2 removal efficiency is in inverse proportion to reaction time, and the results of amine degradation and heat stable salts formation are in accordance with it. The SO 2 removal efficiency is almost 100%. After the addition of SO 2 to the simulated flue gas, there is more serious amine degradation and more heat stable salts formation. Four kinds of organic acid salts, such as formate, acetate, oxalate, and glycolate, were detected with and without SO 2 . The analysis on mass transfer and CO 2 reaction rate indicates that the free amine concentration reduction is the main reason for the CO 2 removal efficiency decreases. The combination of SO 2 with amine results in the decrease in free amines.

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Indoor and outdoor particulate matter 2.5 (PM 2.5) concentrations were monitored in seven sampling sites: basketball stadium, hotel, shopping centre, research centre, commercial office, apartment building and villa, to determine the indoor and outdoor relationship of PM 2.5 mass concentration in the central area of Beijing from February 2014 to March 2014. The influence of four types of ventilation systems on indoor to outdoor (I/O) ratio of PM 2.5 concentration was evaluated. The measured results show that the mean I/O ratio of the seven locations was 0.36 when the outdoor PM 2.5 concentration was more than 150 mg/m 3 , and 1.1 when the outdoor PM 2.5 concentration was less than 100 mg/m 3 , which implies that people's activities could be the most likely factor rather than outdoor sources for elevated indoor PM 2.5 levels. The average I/O ratio was 0.69 for public buildings and 0.94 for residential homes, which illustrates that indoor PM 2.5 concentrations could be dominated by outdoor sources for residential homes. Approximately 90% of the outdoor particles were removed in public buildings equipped with fan-coil unit with air cleaning plus fresh air system. The results demonstrate the need to improve indoor air quality by using a proper ventilation system with air cleaning.

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