This review covers the sustainable development of advanced improvements in CO2 capture and utilization.

A novel phase splitter, namely, sulfolane, was proposed to advance the traditional monoethanolamine (MEA) absorption technology for CO2 capture by simultaneously promoting the absorption rate and lowering heat duty. The phase-splitting phenomenon was observed after the CO2 loading level had exceeded 0.73 mol CO2/L, thereby generating a CO2-rich MEA upper layer and a lower layer containing sulfolane. Sulfolane facilitated CO2 absorption because of its strong affinity with acid gases, which resulted in an absorption rate 2.7 times higher than that of the conventional MEA process. The process simulation using Aspen Plus indicated that the regeneration heat with the MEA/sulfolane mixture as a solvent substantially decreased to 2.67 GJ/t-CO2, which was 31% lower than that of the conventional MEA process (3.85 GJ/t-CO2). Moreover, the sensible heat and vaporization heat of MEA/sulfolane were markedly decreased by 62.4% and 47.9%, which could be ascribed to the decreased stripping volume and relatively high CO2 partial pressure caused by liquid–liquid phase separation. The proposed system is proved to be a promising candidate for the advancement of CO2 capture techniques with high CO2 absorption capacity, rapid absorption rate, and low-energy penalty.

Aberrant DNA methylation can be a potential genetic mechanism in non-small cell lung cancer (NSCLC). However, inconsistent findings existed among the recent association studies between cigarette smoking and gene methylation in lung cancer. The purpose of our meta-analysis was to evaluate the role of gene methylation in the smoking behavior of NSCLC patients. A total of 116 genes were obtained from 97 eligible publications in the current meta-analyses. Our results showed that 7 hypermethylated genes (including CDKN2A, RASSF1, MGMT, RARB, DAPK, WIF1 and FHIT) were significantly associated with the smoking behavior in NSCLC patients. The further population-based subgroup meta-analyses showed that the CDKN2A hypermethylation was significantly associated with cigarette smoking in Japanese, Chinese and Americans. In contrast, a significant association of RARB hypermethylation and smoking behavior was only detected in Chinese but not in Japanese. The genes with altered DNA methylation were likely to be potentially useful biomarkers in the early diagnosis of NSCLC.

NiCo2O4 nanodots decorated graphitic carbon nitride (g-C3N4) heterojunction was synthesized based on the energy band matching theory for efficient photocatalytic hydrogen evolution reaction under simulated solar irradiation. NiCo2O4 species (E g = 1.77 eV) are uniformly anchored on the surface of g-C3N4 for the formation of NiCo2O4/g-C3N4 heterojunction to enhance the light response of the hybrid catalyst. The NiCo2O4/g-C3N4 heterojunction generates more structure defects, favoring the photocatalysis by accelerating the separation and transfer of the photoexcited electrons and holes and suppressing the recombination of the photoinduced carries. At the heterojunction interface, the photogenerated electrons transfer from the conduction band of NiCo2O4 to that of g-C3N4, while the photogenerated holes transfer from the valence band of g-C3N4 to that of NiCo2O4, making more active electrons participate in the generation of hydrogen. Compared with the pristine g-C3N4 and NiCo2O4, a NiCo2O4/g-C3N4 heterojunction sample (NC-6%) shows a hydrogen generation rate at 462.4 μmol·g–1·h–1, reaching 2.2 times and 400 times higher than that of g-C3N4 and NiCo2O4, respectively.

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Amine-based CO2 capture technology requires high-energy consumption because the desorption temperature required for carbamate breakdown during absorbent regeneration is higher than 110 °C. In this study, we report a stable solid acid catalyst, namely, SO4 2–/ZrO2-HZSM-5 (SZ@H), which has improved Lewis acid sites (LASs) and Bronsted acid sites (BASs). The improved LASs and BASs enabled the CO2 desorption temperature to be decreased to less than 98 °C. The BASs and LASs of SZ@H preferred to donate or accept protons; thus, the amount and rate of CO2 desorption from spent monoethanolamine were more than 40 and 37% higher, respectively, when using SZ@H than when not using any catalyst. Consequently, the energy consumption was reduced by approximately 31%. A catalyzed proton-transfer mechanism is proposed for SZ@H-catalyzed CO2 regeneration through experimental characterization and theoretical calculations. The results reveal the role of proton transfer during CO2 desorption, which enables the feasibility of catalysts for CO2 capture in industrial applications.

Biphasic solvents containing mixed amines have a phase separation behavior and energy-efficient regeneration for CO2 capture. However, the trade-off between the CO2 absorption capacity and the volume ratio of the CO2-rich phase presents a critical challenge to the reducing potential in regeneration energy consumption. In this study, sulfolane was proposed to regulate the phase separation behavior of a N,N-diethylethanolamine (DEEA)–triethylenetetramine (TETA) biphasic absorbent by simultaneously decreasing the volume ratio and increasing the CO2 loading of the rich phase, without sacrificing the high CO2 capacity. In the DEEA–TETA–sulfolane biphasic absorbent, sulfolane acted as a phase splitter and physical activator. The replacement of a part of H2O by hydrophobic sulfolane contributed to a substantial decrease in the volume ratio of the rich phase from 83 to 39% and an increase in CO2 loading of the rich phase from 3.10 to 4.92 mol/L. The regeneration heat decreased to 1.81 GJ/t CO2, 26.4% less than DEEA–TETA, and 54.6% less than the 5 M monoethanolamine system. Moreover, by promoting the mass transfer coefficient of CO2 in DEEA–TETA–sulfolane to 1.8 times the original DEEA–TETA system, sulfolane was validated as a physical activator. Our study provides a promising strategy for regulating the phase separation behavior of biphasic solvents and enhancing the regeneration energy efficiency for CO2 capture.

A nanocasting method to fabricate nitrogen-doped dual mesoporous carbon is proposed by the carbonization of nitrile functional ionic liquid (FIL) grafted SBA-15 for the first time. These carbon materials have high nitrogen content (12.8%), large specific surface areas (763 m(2) g(-1)) and uniform rod morphologies, which are derived from FILs grafted on the surface of SBA-15. Furthermore, by adjusting the impregnation amount of ionic liquids on SBA-15, pore structures of these carbon materials can be adjusted from single to dual mesopores. The developed dual mesoporous carbon materials exhibit good catalytic performance in the selective oxidation of ethylbenzene, ascribed to the promoting effects of nitrogen-doping, high surface area and dual mesostructure. It may be concluded that the dual mesostructure has an advantage over a single mesostructure to obtain a fast mass transport rate, resulting in higher acetophenone yield.