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Potassium-promoted layered double hydroxide (LDH)-derived materials are suitable elevated temperature CO2 adsorbents for pre-combustion CO2 capture. A challenge for the commercialization of LDHs as efficient CO2 adsorbents is their low capacities (ca. 0.5–0.6 mmol/g@400 °C) due to their hydrogen-bonded stacked structure. In this study, the aqueous miscible organic solvent treatment (AMOST) was used to exfoliate Mg3Al–CO3 LDH into nanosheets with a flower-like morphology, resulting in high surface areas of 287 and 212 m2/g for CC1 (washed with ethanol) and CC2 (washed with acetone), respectively. The exfoliated LDH structure exposed more interlayered CO2 active sites and promoters for alkali metal modification. Six impregnation solvents, water, acetone, ethanediol, ethanol, DMAC, and methanol were screened to optimize the CO2 uptake of 20 wt% K2CO3-promoted CC1. K2CO3/CC1(ed) using ethanediol as the impregnation solvent reached a CO2 working capacity of 1.46 mmol/g at 400 °C in the first cycle and 1.23 mmol/g after 10 cycles, twice the capacity of the commercial K2CO3/MG70. Material characterization indicated that the unexpectedly high performance of K2CO3/CC1(ed) could be attributed to the uniform K+ dispersion on the surface of K2CO3/CC1(ed) rather than bulk phase formation and the release of the residual solvent during calcination that could generate more paths for CO2 diffusion. [ABSTRACT FROM AUTHOR]

The search for efficient amine-functionalized materials for direct air capture (DAC) of CO2 is highly important to achieve negative emissions. Here we report a new family of class 1 adsorbents for DAC by loading 67 wt% branched poly(ethylenimine) (PEI) onto Mg–Al–CO3 layered double hydroxide-derived mixed metal oxides (MMOs), which exhibit unexpectedly large CO2 uptakes (2.27 mmol g−1), fast kinetics (1.1 mmol g−1 h−1), and high stability over 20 cycles at 25 °C under 0.4 mbar CO2. The prepared MMO nanosheets are self-assembled into spherical shaped particles with abundant slit-like mesopores and broad pore size distribution. This ideal nanostructure leads to the uniform distribution of the impregnated PEIs and optimal accessibility for CO2 molecules. The defect-abundant MMO layers provide strong electrostatic attraction to the attached polyamines, making the hybrid adsorbents thermally robust up to 300 °C. Enhanced capacity and stability are observed in the presence of moisture, thus facilitating the use of steam stripping to concentrate the desorbed CO2. [ABSTRACT FROM AUTHOR]

The basicity and acidity of solvent-treated layered double hydroxide (ST-LDHs) and their layered double oxides (ST-LDOs) have been fully studied using Hammett titration, in situ FTIR, CO2-TPD and NH3-TPD. Five solvents (ethanol, acetone, isopropanol, ethyl acetate and 1-hexanol) were selected to treat [Mg0.72Al0.28(OH)2](CO3)0.14 (Mg2.5Al-CO3 LDH) and compared with traditional LDH co-precipitated from water. The Brønsted basicity strength of the ST-LDHs and ST-LDOs increased but was accompanied by a decrease in basic site density. In addition, the Lewis acidity of ST-LDOs also changes significantly, with medium strength Lewis acid sites dissapearing after solvent treatment. We found that the CO2 capture capacity of solvent treated LDOs is 50% higher than that of traditional co-precipitated LDO sample. The ethanol treated LDO exhibited the highest CO2 uptake of 1.01 mmol g−1. The observed CO2 capture performance of the ST-LDOs correlates linearly with the ratio of total acid sites to total basic sites. [ABSTRACT FROM AUTHOR]

A mold foaming process for preparing thermoplastic polyurethane foam sheets was proposed and realized in pilot scale hot-press machine based on the mechanism of solid-state polymer foaming. Thermoplastic polyurethane microcellular sheets with volume expansion ratios of 2.2–7.0 were prepared by adjusting foaming temperature of 95–120°C at the fixed CO2 pressure of 12 MPa with natural post-curing. The good foam dimensional stability and the uniform cell morphology of these thermoplastic polyurethane foams suggested that the mold foaming of thermoplastic polyurethane sheet was feasible. Regardless of volume expansion ratio, a linear shrinkage of 17–19% occurred to all thermoplastic polyurethane foams after post-curing. The flexible properties of these post-cured thermoplastic polyurethane foams, such as hardness, rebound resilience, compression set, and dynamic shock absorption, were investigated. The test results indicated that these thermoplastic polyurethane foams were excellent flexible materials. [ABSTRACT FROM AUTHOR]

Oxymatrine has a variety of pharmacological functions, including anti-viral, anti-liver fibrotic, anti-cancer, anti-bacterial, anti-epidemic, analgesic, anti-allergy and anti-inflammatory properties. The present study aimed to investigate the protective effects of oxymatrine against lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver failure and the associated underlying mechanisms. Mice were administrated 4 mg/kg LPS and 600 mg/kg D-GalN. Then, mice in the Oxymatrine group were treated with 120 mg/kg of oxymatrine for 4 weeks. Oxymatrine treatment increased survival rate, decreased plasma aspartate transaminase and alanine aminotransferase activity, increased superoxide dismutase and glutathione peroxidase and decreased malondialdehyde, tumor necrosis factor- and myeloperoxidase activities in mice with LPS/D-GalN-induced liver failure. Furthermore, Oxymatrine activated nuclear factor erythroid 2-related factor (Nrf) 2 and heme oxygenase (HO)-1 protein expression, and suppressed Toll like receptor (TLR)4, myeloid differentiation primary response 88 and nuclear factor-κB protein expression in mice LPS/D-GalN mice. Overall, the present study suggests that oxymatrine effectively attenuates LPS/D-GalN-induced acute liver failure by oxidative damage via activation of Nrf2/HO-1 and modulation of TLR4-dependent inflammatory signaling pathways. [ABSTRACT FROM AUTHOR]