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Harvesting water from the atmosphere is an important process to solve the extreme lack of water resources in arid regions. Adsorption-based atmospheric water harvesting (AWH) takes advantage of solar thermal energy to harvest water from air. This technique is particularly suitable for arid regions characterized by low humidity and an abundance of sunshine. Nonetheless, under low humidity conditions, AWH is highly dependent on water-adsorbing materials exhibiting excellent performance. In this work, a metal–organic framework (MOF), namely [Zn2(bpy) (btec)(H2O)2]·2H2O, also denoted as MWH-1, was investigated for application in water harvesting under low humidity conditions ( 200 cm3∙cm−3; RH = 10%, uptake: >250 cm3∙cm−3). This ensured effective water harvesting at high temperatures during the day. In situ powder X-ray diffraction and Fourier-transform infrared analyses confirmed the sensitive water adsorption process of MWH-1a. The X-ray single-crystal study further demonstrated that single-crystal structures could be completely restored following water harvesting. MWH-1 showed good structural stability and enabled water harvesting under low humidity and high temperature conditions. Thus, it has the potential for application in round-the-clock water harvesting in extremely arid regions.

The nickel-based superconductivity provides a fascinating new platform to explore the high-T c superconductivity. As the infinite-layer nickelates are obtained by removing the apical oxygens from the precursor perovskite phase, the crystalline quality of the perovskite phase is crucial in synthesizing high quality superconducting nickelates. Especially, cation-related defects, such as the Ruddlesden-Popper-type (RP-type) faults, are unlikely to disappear after the topotactic reduction process and should be avoided during the growth of the perovskite phase. Herein, using reactive molecular beam epitaxy, we report the atomic-scale engineering of the interface structure and demonstrate its impact in reducing crystalline defects in Nd-based nickelate/SrTiO3 heterostructures. A simultaneous deposition of stoichiometric Nd and Ni directly on SrTiO3 substrate results in prominent Nd vacancies and Ti diffusion at the interface and RP-type defects in nickelate films. In contrast, inserting an extra [NdO] monolayer before the simultaneous deposition of Nd and Ni forms a sharp interface and greatly eliminates RP-type defects in nickelate films. A possible explanation related to the polar discontinuity is also discussed. Our results provide an effective method to synthesize high-quality precursor perovskite phase for the investigation of the novel superconductivity in nickelates.

Solid adsorbents that simultaneously have high selectivity and uptake capacity are highly promising as alternatives to conventional cryogenic distillation of propene/propane (C3H6/C3H8) separation. Coordinatively unsaturated metal sites (CUS) plays a vital role in selective adsorption of olefins over paraffins. Ultrathin poly (triazine imide) (PTI) nanosheets can reach rapid gas adsorption equilibrium, due to its large surface-to-volume ratio. In this work, combining the advantages of the CUS and the PTI nanosheets, Li CUSs were introduced into the PTI nanosheets for C3H6/C3H8 separation. Density functional theory (DFT) calculations demonstrated the thermodynamic feasibility of incorporating Li CUSs into the PTI nanosheets. These highly exposed Li CUSs were predicted to have a higher adsorption affinity toward C3H6 than C3H8. Using the DFT-derived force field parameters, we further performed grand canonical Monte Carlo (GCMC) simulations to investigate C3H6/C3H8 adsorption on the Li−PTI complexes slit pore model with different pore widths (H). We found that the Li−PTI complexes display considerable C3H6/C3H8 selectivity (4.2∼7.9) under relevant conditions. Moreover, the Li−PTI complexes slit pore have large C3H6 working capacities (1.5∼4.0 mmol g-1), superior to those calculated for the most of adsorbent materials that have been reported. The Li−PTI complexes with slit pore architecture show potential as C3H6/C3H8 separation materials.

In order to remove N2 from low quality natural gas, a mathematical model has been established by Aspen adsorption, using the CH4-selective sorbent silicalite-1 pellets. The dynamic adsorption isotherm was first simulated by breakthrough simulation of a CH4/N2 mixture at different adsorption pressures and feed flow rates based on breakthrough experiments. The resulting simulated CH4 dynamic adsorption amounts were very close to the experimental data at three different adsorption pressures (100, 200, and 300 kPa). Moreover, a single-bed, three-step pressure swing adsorption (PSA) experiment was performed, and the results were in good agreement with the simulated data, further corroborating the accuracy of the gas dynamic adsorption isotherm obtained by the simulation method. Finally, based on the simulated dynamic adsorption isotherm of CH4 and N2, a four-bed, eight-step PSA process has been designed, which enriched 75% (vol) CH4 and 80% (vol) CH4 to 95% (vol) and 99% (vol), and provided 99% (vol) recovery.

Direct separation of high purity ethylene (C2H4) from an ethane (C2H6)/ethylene mixture is a critical and challenging task owing to the very similar molecular size and physical properties of the two components. While some studies have attempted this separation, there is a lack of excellent porous materials with strong binding affinity for C2H6-selective adsorption via an energy-efficient adsorptive separation process. Herein, we report a titanium metal-organic framework with strong binding affinity and excellent stability for the highly efficient removal of C2H6 from C2H6/C2H4 mixtures. Single component adsorption isotherms demonstrated a larger amount of adsorbed ethane (1.16 mmol·g−1 under 1 kPa) and high C2H6/C2H4 selectivity (2.7) for equimolar C2H6/C2H4 mixtures, especially in the low-pressure range, which is further confirmed by the results of grand canonical Monte Carlo simulations for C2H6 adsorption in this framework. The experimental breakthrough curves showed that C2H4 with a high purity was collected directly from both 1:9 and 1:15 C2H6/C2H4 (volume ratio) mixtures at 298 K and 100 kPa. Moreover, the unchanged adsorption and separation performance after cycling experiments confirmed the promising applicability of this material in future.

Novel interpenetrating bimetallic MIL-126(Cr/Sc) has been synthesized using a metal metathesis method, and showed a higher CO2, N2O and C2H2 uptake and binding energy than the parent MIL-126(Sc) material.

Constructing strategies of hierarchically porous MOFs with different pore size ranges and their applications in adsorption and catalysis.

A highly stable Hofmann-based metal−organic framework has been purposely synthesized for efficient C3H6/C3H8 separation through the linker modification strategy using direct mixing method under ambient conditions.

A robust aluminum-based metal-organic framework (Al-MOF) MIL-120Al with 1D rhombic ultra-microporous was reported. The non-polar porous walls composed of para-benzene rings with a comparable pore size to the kinetic diameter of methane allow it to exhibit a novel thermodynamic-kinetic synergistic separation of CH4/N2 mixtures. The CH4 adsorption capacity was as high as 33.7 cm3/g (298 K, 1 bar), which is the highest uptake value among the Al-MOFs reported to date. The diffusion rates of CH4 were faster than N2 in this structure as confirmed by time-dependent kinetic adsorption profiles. Breakthrough experiments confirm that this MOF can completely separate the CH4/N2 mixture and the separation performance is not affected in the presence of H2O. Theoretical calculations reveal that pore centers with more energetically-favorable binding sites for CH4 than N2. The results of pressure swing adsorption (PSA) simulations indicate that MIL-120Al is a potential candidate for selective capture coal-mine methane.

The removal of trace propyne (C3H4) from propyne/propylene (C3H4/C3H6) mixtures is a technical and challenging task during the production of polymer-grade propylene in view of their very similar size and physical properties. While some progress has been made, it is still very challenging to use some highly stable and commercially available porous materials via an energy-efficient adsorptive separation process. Herein, we report the ultrafine tuning of the pore apertures in type-A zeolites for the highly efficient removal of trace amounts of C3H4 from C3H4/C3H6 mixtures. The resulting ion-exchanged zeolite 5A exhibits a large C3H4 adsorption capacity (2.3 mmol g−1 under 10−4 MPa) and high C3H4/C3H6 selectivity at room temperature, which were mainly attributed to the ultrafine-tuned pore size that selectively blocks C3H6 molecules, while maintaining the strong adsorption of C3H4 at low pressure region. High purity of C3H6 (>99.9999%) can be directly obtained on this material under ambient conditions, as demonstrated by the experimental breakthrough curves obtained for both 1/99 and 0.1/99.9 (V/V) C3H4/C3H6 mixtures.

Propane/propylene separation is one of the most challenging and energy-consuming but most important tasks in the petrochemical industry. Herein, a stable hydrogen-bonded organic framework (HOF-FJU-1) was tailor-made for highly efficient propylene separation from binary C

The flue gas from fossil fuel power plants is a long-term stable and concentrated emission source of CO

Two-dimensional (2D) transition metal chalcogenides have attracted enormous attention due to their stunning properties and great prospects for applications. Most of the reported 2D materials have layered structure, and non-layered transition metal chalcogenides are rare. Particularly, chromium chalcogenides are highly complexed in terms of structural phases. Researches on their representative chalcogenides, Cr2S3 and Cr2Se3, are insufficient and most of them focus on individual crystal grains. In this study, large-scale Cr2S3 and Cr2Se3 films with controllable thickness are successfully grown, and their crystalline qualities are confirmed by multiple characterizations. Moreover, the thickness-dependent Raman vibrations are investigated systematically, presenting slight redshift with increasing thickness. The fundamental physical properties of grown Cr2S3 and Cr2Se3 films, including optical bandgap, activation energy and electrical properties, are measured with different thicknesses. The 1.9 nm thick Cr2S3 and Cr2Se3 films show narrow optical bandgap of 0.732 and 0.672 eV, respectively. The electrical properties of Cr2S3 films demonstrate p-type semiconductor behaviours, while the Cr2Se3 films exhibit no gate response. This work can provide a feasible method for growing large-scale Cr2S3 and Cr2Se3 films, and reveal fundamental information of their physical properties, which is helpful for future applications.

Tumor distant metastasis is the primary cause of death in colorectal cancer (CRC) patients. GL-V9 is a newly synthesized flavonoid derivative with several beneficial biological functions including anti-tumor and anti-inflammation. However, the anti-metastatic effect of GL-V9 and related mechanisms in CRC remains unknown. In this study, the anti-invasive and anti-migratory activities of GL-V9 were investigated in CRC cells. Using MTT assay, cell wound healing assay, and transwell migration assay, we showed that GL-V9 suppressed CRC cell viability, migration, and invasion in a concentration-dependent manner. In addition, the protein expression levels as well as activities of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) were significantly reduced after GL-V9 treatment. Further analysis of the underlying mechanism revealed that GL-V9 inhibited PI3K/Akt signaling pathway upstream of MMP-2 and MMP-9. In conclusion, our study demonstrated that GL-V9 could suppress CRC cell invasion and migration through PI3K/Ak and MMP-2/9 axis. Therefore, GL-V9 might be a potential novel therapeutic agent against CRC metastasis.

To isolate iron sulphide and reduce coke adhesion reactions that occur on the surface of a delayed coking furnace, a SiO2 coating was developed on Cr9Mo alloy by employing the sol–gel method. The coating was characterised through Fourier transformation infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, potentiodynamic scanning, InfiniteFocus optical 3D surface metrology, thermal shock and coking experiments. After heat treatment at 550 °C, the silicon methyl groups were oxidised and the coating exhibited a Si–O–Si connected crosslinked network structure. The coating surface was uniformly dense with a roughness and thickness of 0.2 and approximately 4 μm, respectively. The coating still adhered to the substrate tightly after 20 cycles of thermal shock treatment. Compared with an uncoated sample, the coating effectively improved the corrosion resistance of the substrate, suppressed the iron sulphide reaction, and reduced coke adhesion onto the sample. The coating had a better inhibition effect on coke fouling in a delayed coking furnace.

It is a big challenge to separate N2O from CO2 using adsorption because they have similar physical properties. The Fe3+-F- site in MIL-100Fe transforms to an unsaturated Fe2+ site under high-temperature activation (300 °C), and the target sorbent MIL-100Fe-300 exhibits the biggest difference in CO2 and N2O adsorption capacity, and the selectivity of N2O/CO2 (50%/50%) is up to 3.00 at 298 K. According to DFT calculations, the original Fe3+-F- site has strong interaction with CO2, but the open Fe2+ site has a stronger interaction with N2O. Through a breakthrough experiment, it was confirmed that MIL-100Fe-300 has the best N2O/CO2 separation performance, making it potentially a useful material in industry.

The removal of low content of ethane (C2H6) from ethylene (C2H4) using C2H6-selective adsorbents to reduce the energy consumption in the petrochemical industry is one of the meaningful and challenging tasks in separation research. Herein, we report for the first time the systematic research of covalent-organic frameworks (COFs) as a platform used for the separation of light hydrocarbons based on their specific topology. Benefiting from its richly distributed weakly polar surface and suitable pore cavities, COF-1 exhibits the highest adsorption selectivity (1.92 at 298 K and 1 bar) for the C2H6/C2H4 mixture among the COFs studied. Density functional theory calculations clearly revealed that COF-1 can exhibit multiple C-H···π interactions with ethane in its suitable pore environment and thus preferentially binds to ethane over ethylene. Finally, breakthrough experiments proved that COF-1 may be regarded as an effective porous adsorbent with polymer-grade C2H4 obtained directly from C2H6/C2H4 mixtures at 298 K and 1 bar.

The removal of ethane from ethene streams is of great importance and a challenging process for feedstock purification to produce polyethylene in the petrochemical industry. Traditional industrial c...

CH4/N2 separation is one of the great challenges in the gas separation field due to their very close physical properties. In this work, a strategy was proposed to construct specific cages using an aliphatic ligand with suitable size to preferentially adsorb CH4 molecules in metal–organic frameworks (MOFs). As a result, a series of MOFs with trans-1,4-cyclohexanedicarboxylic acid (H2CDC) as the ligand and different metal centres (M-CDC, M represents metal ions) exhibit excellent separation performances for CH4/N2 mixture. To the best of our knowledge, the presented MOFs possess higher selectivity (13.1–16.69) and sorbent selection parameter (SSP) in comparison to the reported porous materials. Especially for the integrated descriptor SSP, the value of Al-CDC is up to 82.0, which is at least 2–3 times higher than those in the reported materials. Breakthrough experiments indicate that CH4/N2 can be completely separated using a packed column of Al-CDC. Theoretical calculations confirmed the preferential trap of CH4 in the cages formed by the aliphatic ligand. In addition, the separation performance can be well maintained even after at least 10 cycles and the treatment of the MOF sample with boiling water, acid and base solution. These results not only introduce promising candidates for CH4/N2 separation, but also provide useful information for the separation of other weak adsorbates with similar properties.