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Capturing CO 2 using clamshell/eggshell-derived CaO adsorbent can not only reduce carbon emissions but also alleviate the impact of trash on the environment. However, organic acid was usually used, high-temperature calcination was often performed, and CO 2 was inevitably released during preparing CaO adsorbents from shell wastes. In this work, CaO-based CO 2 adsorbent was greenly prepared by calcium-induced hydrogenation of clamshell and eggshell wastes in one pot at room/moderate temperature. CO 2 adsorption experiments were performed in a thermogravimetric analyzer (TGA). The adsorption performance of the adsorbents obtained from the mechanochemical reaction (BM-C/E-CaO) was superior to that of the adsorbents obtained from the thermochemical reaction (Cal-C/E-CaO). The CO 2 adsorption capacity of BM-C-CaO at 650 °C is up to 36.82 wt%, but the adsorption decay rate of the sample after 20 carbonation/calcination cycles is only 30.17%. This study offers an alternative energy-saving method for greenly preparing CaO-based adsorbent from shell wastes. • CO 2 adsorbent was prepared by calcium-induced hydrogenation of shell wastes. • Both mechanochemical and thermochemical methods were used. • The CO 2 adsorption capacity of BM-C-CaO at 650 °C is as high as 36.82 wt%. • The adsorption decay rate after 20 carbonation/calcination cycles is only 30.17%. • This study offers a green method for preparing CO 2 adsorbent from shell wastes. [ABSTRACT FROM AUTHOR]

Many efforts have been made to study the reactions of the borohydride with CO 2 in solution. However, it is scarce to achieve the hydrogenation of CO 2 using borohydrides as hydrogen source by the solid-gas direct reaction in the condition of ball milling under ambient temperature. Herein, we investigated the solid-gas noncatalytic reaction of ABH 4 (A = Li or Na) with CO 2 under mechanochemical conditions for the first time. It is found that hydrogen and trimethylborane are formed in the gas phase, as well as borate, formate, and methoxy species are formed in the solid phase. For the reaction of alkali borohydride with CO 2 , hydrogen and trimethylborane are formed in the gas phase, as well as borate, formate, and methoxy species are formed in the solid phase. Image 1 • The solid-gas reaction of alkali borohydride with CO 2 was investigated. • The reaction is carried out at ambient temperature under mechanochemical condition. • The hydrogen and trimethylborane are formed in the gas phase. • The borate, formate, and methoxy species are formed in the solid phase. • The work provides a new method for converting CO 2 using borohydrides. [ABSTRACT FROM AUTHOR]

Abstract An interesting chemically stable metal-organic framework, {(NC 2 H 8) 2 [Cd(DMIPA)]·xG} n (G=guest molecules of H 2 O and DMA, DMA= N , N -Dimethylacetamide) (1), featuring a 4-connected uninodal {42.64} topology and 18 Å × 18 Å snowflake-like channels along the c axis with exposed thioether groups, was assembled by employing a tetratopic polycarboxylate ligand of 5,5΄-thiobisophthalic acid (H 4 DMIPA). Ligand-based photoluminescence and solvent-dependent fluorescent intensities were exhibited in compound 1. Most strikingly, it showed remarkable sensitivity and selectivity toward Fe3+ ions under the presence of other metal ions. The photoluminescence quenching could be detected at a very low concentration of 1.62 ppm, and the maximum quenching efficiency was found to be 97.2% at 0.175 mM. Significantly, compound 1 can be recycled after use. The fluorescence intensity and quenching percentage of 1 exhibited very little changes after being used for ten successive cycles (I 0 = 6349–6093, and QP = 95.4–96.2%), indicating that 1 is a very promising MOFs-based sensor with remarkable sensitivity, selectivity, and reusability towards Fe3+ ions. Graphical abstract An interesting chemically stable metal-organic framework, {(NC 2 H 8) 2 [Cd(DMIPA)]·xG} n (G=guest molecules of H 2 O and DMA, DMA= N , N -Dimethylacetamide) (1), featuring a 4-connected uninodal {42.64} topology and 18 Å × 18 Å snowflake-like channels along the c axis with exposed thioether groups, was assembled by employing a tetratopic polycarboxylate ligand of 5,5΄-thiobisophthalic acid (H 4 DMIPA). fx1 Highlights • A chemically stable anionic framework with exposed thioether groups in the 18 Å × 18 Å snowflake-like channels was assembled. • It showed remarkable sensitivity and selectivity toward Fe3+ ions under the presence of other metal ions. • The photoluminescence quenching could be detected at a very low concentration of 1.62 ppm. • The maximum quenching efficiency was found to be 97.2% at 0.175 mM. [ABSTRACT FROM AUTHOR]

The coordination characteristics of 4-bromoisophthalic acid (4-Br-H 2 ip) have been investigated in a series of Cd II -based frameworks. Hydrothermal reactions of Cd II salts and 4-Br-H 2 ip together with flexible or semiflexible N-donor auxiliary ligands resulted in the formation of four three-dimensional coordination complexes with diverse structures: {Cd(bix) 0.5 (bix) 0.5 (4-Br-ip)]·H 2 O} n ( 1 ), [Cd(bbi) 0.5 (bbi) 0.5 (4-Br-ip)] n ( 2 ), {[Cd(btx) 0.5 (4-Br-ip)(H 2 O)]·0.5CH 3 OH·H 2 O} n ( 3 ) and {[Cd(bbt) 0.5 (4-Br-ip)(H 2 O)]·3·5H 2 O} n ( 4 ). These compounds were characterized by elemental analyses, IR spectra, single-crystal and powder X-ray diffraction. They displayed diverse structures depending on the configuration of the 4-connected metal node, the coordination mode of the 4-Br-H 2 ip, the coordination ability and conformationally flexibility of the N-donor auxiliary. Compound 1 exhibits 3-fold interpenetrated 6 6 topology and compound 2 has a 4 12 topology. Compounds 3 – 4 have similar 3D pillar-layered structures based on 3,4-connected binodal net with the Schläfli symbol of (4·3 8 ). The thermal stabilities and photoluminescence properties of them were discussed in detail. [ABSTRACT FROM AUTHOR]

The preparation of clean fuel or CO 2 adsorbents using industrial and domestic garbage is an alternative way of meeting global energy needs and alleviating environmental problems. Herein, H 2 -mixed CH 4 fuel and CaO-based CO 2 sorbent were first prepared in one pot by the mechanochemical reaction of pretreated clamshell or eggshell wastes (carbon and calcium source) with calcium hydride (hydrogen source) at room temperature. In the above reactions, CH 4 was the sole hydrocarbon product, and its yield reached 78.23%. The H 2 /CH 4 ratio of the produced H 2 -mixed CH 4 fuel was tunable according to the need by changing the reaction conditions. It is inspiring that the simultaneously formed solid CaO/carbon products were efficient CaO-based sorbents, which possessed a higher CO 2 adsorption capacity (49.81–58.74 wt.%) at 650 °C and could maintain good adsorption stability in 30 carbonation/calcination cycles (average activity loss per cycle of only 1.6%). The three achievements of the idea are that it can simultaneously eliminate clamshell or eggshell wastes, obtain valuable clean fuel, and acquire efficient CaO-based sorbents. H 2 -mixed CH 4 fuel and CaO-based CO 2 sorbent were prepared simultaneously by the mechanochemical reaction of shell waste with calcium hydride. [Display omitted] • Mechanochemical reaction of shell wastes with CaH 2 was first studied. • H 2 -mixed CH 4 fuel and CaO-based CO 2 sorbent were successfully prepared in one pot. • CH 4 was the sole hydrocarbon product and its yield can reach as high as 78.23%. • The CaO products possess higher CO 2 absorption capacity and cycling stability. • This process eliminates shell wastes, obtains clean fuel and efficient CO 2 sorbents. [ABSTRACT FROM AUTHOR]

We report an efficient, convenient, solution-free method to achieve the room-temperature dehydrogenation of alkaline earth metal hydrides (MgH 2 and CaH 2). It is found, for the first time, that metal carbonates, which are readily available and cheap, can efficiently induce the hydrogen desorption of alkaline earth metal hydrides at room temperature under mechanical ball milling conditions. We demonstrate that the hydrogen yield and purity mainly depend on the nature of metal carbonates, rate and duration of ball milling, and reaction mixture composition. The best performances are obtained with the systems of MgCO 3 -MgH 2 and MgCO 3 -CaH 2 milled at 350 ​rpm for 12 ​h, with the CO x -free hydrogen yield of 94% and 90%. This work opens a new way to achieve the efficient dehydrogenation of alkaline earth metal hydrides at room temperature. It is found, for the first time, that metal carbonates can efficiently induce the hydrogen desorption of alkaline earth metal hydrides (MgH 2 and CaH 2) at room temperature under mechanical ball milling condition. Image 1 • Metal carbonates can induce the dehydrogenation of MgH 2 and CaH 2 at room temperature. • Hydrogen yield depends on the nature of metal carbonate and duration of ball milling. • Hydrogen yield also depends on rate of ball milling and reaction mixture composition. • For MgCO 3 -added MgH 2 and CaH 2 , hydrogen yields are achieved as high as 94% and 90%. • The work opens a new way to achieve the dehydrogenation of MgH 2 and CaH 2. [ABSTRACT FROM AUTHOR]