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Carbon capture and storage (CCS) technology is considered as one of the most effective short-term solutions in reducing atmospheric CO2 concentrations. A key of CCS technology is to seek the absorbent with low cost, fast absorption rate, and high stability. In this study, we show that 2-ethyl-4-methylimidazole is particularly suitable for efficient CO2 capture. The aqueous solution of 2-ethyl-4-methylimidazole displays a maximum CO2 molar absorption capacity of 1.0 mol∙mol−1 and the absorbed CO2 can be completely released through heating the solution at a relatively low temperature (in-situ attenuated total reflection infrared absorption spectroscopy and 13C nuclear magnetic resonance spectroscopy studies reveal that the intermediates are HCO3− and H2CO3 in the process of CO2 absorption–desorption. These intermediates are easily decomposed, which are responsible for the low CO2 desorption temperature and high desorption efficiency of the system. Moreover, the aqueous solution of 2-ethyl-4-methylimidazole is able to separate and purify CO2 from flue gas and even ambient air. Consequently, 2-ethyl-4-methylimidazole is a promising low-cost CO2 absorbent for industrial implementation.

The development of the sustainable synthesis of zeolites has become a very hot topic in recent years. Herein, we report a sustainable route for synthesizing all-silica SOD zeolite under solvent-free conditions. The method of solvent-free synthesis includes mixing, grinding, and heating raw solids. The all-silica SOD zeolite obtained was well characterized by multiple measurement techniques (XRD, SEM, IR, thermogravimetric-differential thermal analysis (TG-DTA), and magic angel spinning nuclear magnetic resonance (MAS NMR)). The crystallization process of all-silica SOD zeolite was also investigated in detail by XRD, SEM, UV-Raman, and MAS NMR techniques. In addition, the effects of the crystallization compositions, including the molar ratios of Na2O/SiO2 and ethylene glycol/SiO2, on the synthesis of the pure all-silica SOD zeolite were investigated at different temperatures.

The nanocomposite preparation procedure plays an important role in achieving a well-established heterostructured junction, and hence, an optimized photocatalytic activity. In this study, a series of g-C3N4/ZnO nanocomposites were prepared through two distinct procedures of a low-cost, environmentally-friendly, in-situ fabrication process, with urea and zinc acetate being the only precursor materials. The physicochemical properties of synthesized g-C3N4/ZnO composites were mainly characterized by XRD, UV⁻VIS diffuse reflectance spectroscopy (DRS), N2 adsorption-desorption, FTIR, TEM, and SEM. These nanocomposites’ photocatalytic properties were evaluated in methylene blue (MB) dye photodecomposition under UV and sunlight irradiation. Interestingly, compared with ZnO nanorods, g-C3N4/ZnO nanocomposites (x:1, obtained from urea and ZnO nanorods) exhibited weak photocatalytic activity likely due to a “shading effect„, while nanocomposites (x:1 CN, made from g-C3N4 and zinc acetate) showed enhanced photocatalytic activity that can be ascribed to the effective establishment of heterojunctions. A kinetics study showed that a maximum reaction rate constant of 0.1862 min-1 can be achieved under solar light illumination, which is two times higher than that of bare ZnO nanorods. The photocatalytic mechanism was revealed by determining reactive species through adding a series of scavengers. It suggested that reactive ●O2− and h+ radicals played a major role in promoting dye photodegradation.

We report a solvent-free synthesis of all silica Beta zeolite using a cheap organic template of tetraethylammonium bromide (TEABr). The method includes mixing, grinding and heating solid raw material in the absence of water solvent but the presence of zeolite seeds. The absence of water solvent significantly improves the efficiency of synthesis, while the addition of seeds remarkably enhances the crystallization rate. In addition, the use of a cheap organic template of TEABr greatly decreases the synthesis cost. The effects of the reaction compositions, including the molar ratios of NH4F/SiO2, TEABr/SiO2, and mass ratios of seeds to the silica, on the synthesis of the pure product were investigated using different temperature. Physicochemical characterizations, including XRD, SEM, TG and N2 sorption, show that the zeolitic product has good crystallinity, uniform crystals, and high surface area.