Investigation of CO₂ Capture in Nonaqueous Ethylethanolamine Solution Mixed with Porous Solids

In this work, the postcombustion CO₂ capture performance was explored in 100.000 g of a nonaqueous solution, 30 wt % monoethylethanolamine (EMEA) and 70 wt % diethylethanolamine (DEEA). Porous solids (multiwalled carbon nanotubes (MWCNTs), silica gel (SG), and MCM-41) with mass fractions (0.025, 0.050, 0.100 and 0.200%) were added into the pure nonaqueous solution forming the new absorbents to improve the CO₂ capture performance. The CO₂ absorption (313 K) and desorption (383 K) of the new absorbents were operated in the absorption–desorption apparatus under atmospheric pressure. The results show that the addition of the porous solids in the nonaqueous solution led to a 2% decrease in the absorption loading, while contributing to a 10 min decrease in the desorption time under the same desorption extent. The maximum desorption rates of the new absorbents peaked about 5 min earlier than that of the nonaqueous solution, with an enhancement order of MWCNTs > MCM-41 > SG. Meanwhile, the new absorbent, nonaqueous solution mixed with 0.050% MWCNTs, had the best enhancement in the desorption process and exhibited a good stability in the absorption–desorption experiment. Analytic methods (XRD, BET, FT-IR, and SEM) were used to characterize MWCNTs before and after the five absorption–desorption cycles, which showed a good stability of MWCNTs with no significant change in the structure and activity

Solubility and Characterization of CO₂ in 40 mass % <i>N</i>‑Ethylmonoethanolamine Solutions: Explorations for an Efficient Nonaqueous Solution

The CO₂ solubility in <i>N</i>-ethylmonoethanolamine (EMEA) solutions was investigated using the vapor–liquid equilibrium (VLE) and the absorption–desorption apparatus. A tertiary amine, <i>N</i>,<i>N</i>-diethylethanolamine (DEEA), was used as a novel solvent, and other nonaqueous solvents, diethylene glycol, triethylene glycol, benzyl alcohol, <i>n</i>-butyl alcohol and polyethylene glycol-200, were used for comparison. The EMEA + DEEA solution displayed a much higher CO₂ solubility than other nonaqueous solutions though lower than the EMEA + H₂O solution in the VLE experiment. However, the EMEA + DEEA solution exhibited a higher cyclic absorption capacity than EMEA + H₂O solution in the cyclic absorption–desorption experiment. The reaction mechanism of EMEA + DEEA + CO₂ was investigated by ¹³C NMR spectroscopy, which indicated that the nonaqueous solvent of DEEA participated in the chemical absorption of CO₂, and thus improved the CO₂ solubility. The tertiary amine DEEA used as a nonaqueous solvent shows more excellent performance than alcohols and glycols

Regenerable CuO-Based Adsorbents for Low Temperature Desulfurization Application

A series of CuO-based adsorbents for deep removal of H₂S at low temperature was prepared by a coprecipitation method. It was found that CuO-based adsorbents are able to remove H₂S from a CO₂ stream to less than 0.1 ppm at 40 °C. Among them, Fe–Cu–Al–O adsorbent exhibited the highest breakthrough capacity of 113.9 mg g^–1, which is more than 6 times that of pure CuO. The breakthrough capacity was also dependent on the adsorption temperature, space velocity, balance gas, and calcination temperature. The proper adsorption temperature should be lower than 100 °C in the presence of CO₂, and a higher space velocity and calcination temperature could decrease the breakthrough capacity significantly. In addition, the CuO-based adsorbents had a regeneration rate of 43–90% in air at a relative low temperature from 100 to 200 °C with a stable breakthrough capacity after four adsorption–regeneration cycles

Kinetics of CO₂ Absorption in an Ethylethanolamine Based Solution

The kinetics of CO₂ absorption in ethylethanolamine based solutions were investigated using a wetted wall column (WWC) from 298 to 328 K. In the nonaqueous solutions, monoethylethanolamine (EMEA) was the reactant with a concentration range from 0.5 to 3.0 kmol m^–3, and diethylethanolamine (DEEA) was the solvent. Water with volume ratio range from 0 to 150 % was added into 3.0 kmol m^–3 EMEA + DEEA solution forming hydrated solutions. The overall reaction rate constants were obtained from the CO₂ flux under the condition of a pseudo-first-order and fast reaction regime. The reaction rate of CO₂ with nonaqueous solutions increased with either EMEA concentration or temperature, which can be represented by the termolecular mechanism. The reaction rate of CO₂ with hydrated solutions increased with water volume ratio, which can be represented by both the zwitterion and the termolecular mechanisms

Additional file 1 of The application of a 4D-printed chitosan-based stem cell carrier for the repair of corneal alkali burns

Additional file 1. Fig S1. The corresponding isotype control image for the rLESC group in Fig. 3c. The isotype control antibody was rabbit IgG (Abcam, AB172730). Fig S2. Representative images of the corneal opacity, neovascularization, and the repair of damaged corneal epithelium in 4D-CTH-rLESC group at 30 and 60 days. Fig S3. Representative immunofluorescence images of corneal epithelium labeled with CK3/CK12 observed under low magnification in 4D-CTH-rLESC group. Cytokeratin 3 and 12 (red) were used as markers of the epithelium. Scale bars =500 μm