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Cerium dioxide nanocrystals embedded in porous carbon rod materials were used for sulfur storage and embedding. Polar cerium dioxide effectively adsorbed polysulfide and inhibited the shuttle effect. By calculating the diffusion coefficient of the lithium-ions, it was concluded that the porous carbon rod material with cerium oxide was beneficial for the rapid binding of lithium ions and sulfur. [ABSTRACT FROM AUTHOR]

A flexible metal–organic framework (MOF) [Mn(INA)2]·MeOH (1) (INA− = isonicotinate) has been solvothermally synthesized. Single-crystal X-ray diffraction reveals that compound 1 features a 3D microporous framework containing one-dimensional channels. The activated phase 1a displays permanent porosity with a Brunauer–Emmett–Teller (BET) surface area of 236 m2 g−1. Gas sorption analyses reveal that 1a exhibits interesting gate-opening hydrocarbon sorption behavior with considerable C2 uptake capacities but a negligible amount for CH4 under ambient conditions. Selectivity calculation and breakthrough experiment comprehensively demonstrate that 1a has remarkably high selectivity towards C2 hydrocarbons over CH4 under ambient conditions. [ABSTRACT FROM AUTHOR]

In this work, a series of UiO topology structures were synthesized by choosing the same metal-containing clusters with variable length and functional group/site organic linkers, which provided a systematic platform to explore the pore size and functionalization effects on the adsorption and separation of light hydrocarbons. Based on the adsorption and separation experiments, it can be concluded that alkane mixtures CH4/C2H6/C3H8 showed better separation results in the larger pore channels found in UiO-67, Zr-NDC and UiO-66. In addition, functionalization in the pores indicated that the C2H2/C2H4 mixtures can be separated using BUT-11 due to the strong interactions between the C2H2 molecules and the sulfone groups present in the material. [ABSTRACT FROM AUTHOR]

Cu(1,3-BDC) (1,3-BDC = 1,3-benzenedicarboxylic acid) was found in the interpenetrated metal–organic frameworks [Cu(1,3-BDC)(H2O)]·2H2O and Cu(1,3-BDC)(PY)2. We studied their CO2, CH4, and N2 adsorption isotherms at high pressure (10 bar) and used density functional theory methods to locate their most stable configurations. We show that [Cu(1,3-BDC)(H2O)]·2H2O has a high adsorption selectivity of CO2 over CH4 because of the total lack of CH4 adsorption. Although Cu(1,3-BDC)(PY)2 has the same layered substrate as [Cu(1,3-BDC)(H2O)]·2H2O, except for the insertion of pyridine rings between layers, it adsorbs significantly more CH4, leading to decreased CO2/CH4 adsorption selectivity and increased CH4/N2 adsorption selectivity. Our experimental and theoretical studies reveal that introducing suitable organic ligands provides more adsorption sites for CH4, while the ligands' occupancy of the spaces between the layers prevents the spread of CO2 molecules. [ABSTRACT FROM AUTHOR]

A system for interfacing dark field microscopy (DFM) with capillary electrophoresis (CE) was demonstrated and applied to investigate the movement of single gold nanoparticles (AuNPs) visually and in real time for the first time. When using ∼60 nm cetyl trimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) capped AuNPs as target analytes, preliminary data indicated that differently charged AuNPs had different movement velocities (v). From the result of the effect of applied voltage and buffer pH value on the movement of single AuNPs, we could “image” that positively charged CTAB-capped AuNPs (red) moved faster than negatively charged SDS-capped AuNPs (green), and the former could catch up with and pass the latter. The results visually confirmed the separation rules and some fundamental theories of CE including the effect of buffer pH value on the electroosmotic flow (EOF) and the plug-like profile of EOF. This novel integration was successfully utilized to evaluate the size distribution and homogeneity of AuNPs, from which the results obtained were in accordance with transmission electron microscopy (TEM) results. The proposed system offers a new insight into CE analysis and has potential applications in many fields, such as the study of interaction between NPs and biomolecules in bioanalysis. [ABSTRACT FROM AUTHOR]

Since exhaled ammonia (NH3) is one of the metabolic markers of liver and kidney diseases, ammonia visual sensing materials in humid environments have received extensive attention and investigation. Herein, through a tailor-made pore environment provided by metal–organic framework (MOF) materials (CH3-Cu(BDC)), we achieved NH3 anti-interference sensing with apparent color changing under humid conditions. With methyl (CH3–) functionalization, CH3-Cu(BDC) demonstrated a strong response for trace ammonia and showed high selectivity under a humid environment. Grand canonical Monte Carlo (GCMC) simulations indicated that CH3-Cu(BDC) showed stronger attraction towards NH3 molecules than H2O. Benefiting from the target changing coordination environment, CH3-Cu(BDC) showed a rapid response and simple analysis properties for patients' exhaled air. The strategy used in this study not only provides a demonstration case for NH3 colorimetric sensing with high humidity and anti-interference but also introduces a new method for painless and quick exhaled breath analysis for diagnosis of patients with kidney and liver diseases. [ABSTRACT FROM AUTHOR]

In this study, experiments and molecular dynamics simulations were combined to get insights into the role of solvent during the process of xylose conversion under catalyst-free conditions. Solvents used for furfural production were comparatively discussed, including traditional and emerging biomass-derived solvents – water, dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), isopropanol (ISO), γ-butyrolactone (GBL) and γ-valerolactone (GVL). The degradation behavior of solvents, the solubility and α/β ratio of xylose, the distribution of the solvent around xylose/furfural and the hydrogen bonding between them were also studied. The results showed that in pure solvents, the different hydrogen bonding between xylose and the solvent resulted in different products. Water was a favourable solvent for xylose to form furfural among these pure solvents because less formic acid was produced from xylose in water under catalyst-free conditions. Furfural could be produced in mixed solvents if there was more water around xylose, which was similar to the case in pure water. Otherwise, the situation in mixed solvents was similar to that in the corresponding pure organic solvents. GBL and GVL, as green solvents, had weaker affinities with xylose than DMSO, DMF and ISO, but were intensively attracted by furfural, thus they could provide protective shells for furfural, which played a positive role during the production of furfural. The highest furfural yield of 46.4% was achieved in GBL–H2O at 180 °C – 150 min in the absence of catalysts. [ABSTRACT FROM AUTHOR]

In this work, we show that precise control of the pore size and functionality in an ultramicroporous metal–organic framework platform can finely tune the adsorption selectivity between acetylene and carbon dioxide at will. [ABSTRACT FROM AUTHOR]

A novel metal–organic framework, ZJU-196, with extraordinary acid–base resistant stability has been successfully synthesized, exhibiting highly efficient separation of acetylene from C2H2/CO2 mixtures under ambient conditions. [ABSTRACT FROM AUTHOR]

We report a facile, green, and versatile synthetic route that exploits hydroxy double salt (HDS)–template synergy to achieve hierarchically structured metal–organic frameworks (H-MOFs) with high space–time yields (STYs). Hierarchically structured HKUST-1 and ZIF-8 were synthesized using the cooperative template strategy within 30 min (crystallization time). The resulting MOF products exhibited multimodal, hierarchically porous structures with meso-/macropores interconnected with micropores, as revealed by scanning electron microscopy, transmission electron microscopy, N2 adsorption–desorption isotherms, and pore size distributions. The porosities of the produced H-MOFs varied with the amount and type of template. The synergistic effect of the HDS and template on meso-/macropore generation was elucidated. The synergistic effect disclosed here dramatically extends the choice of templates for H-MOF synthesis at room temperature and pressure. Furthermore, the rapid synthetic method is readily scalable with an STY of up to 2366 kg m−3 d−1, a new record for the synthesis of hierarchically structured HKUST-1. The green, versatile, and sustainable method developed in this work provides a new direction for the rapid synthesis of various H-MOFs with tuneable porosities and high STYs for a wide range of applications. [ABSTRACT FROM AUTHOR]

The present report focuses on the solvent effect on furfural production from xylose in biphasic systems with methods including combined experiments, molecular dynamics (MD) simulations and density functional theory (DFT) calculations. Six most effective and commonly used biphasic solvents for furfural production were comparatively analyzed and discussed based on the kinetic study, partition coefficient, degradation behavior of furfural in organic solvents, distribution of solvent molecules around xylose/furfural molecules, hydrogen bonding, moving trajectories of xylose/furfural, and the solvation free energy. During the hydrothermal reaction of xylose to furfural in biphasic systems, it was found that the conversion efficiency of biphasic systems can be ordered as DCM/H2O > 2-MTHF/H2O > 2-butanol/H2O ≈ MIBK/H2O > CPME/H2O > toluene/H2O according to the xylose conversion and furfural yield, which are dominated by the solvation free energy (ΔGsol) of furfural in organic solvents, and also be affected by three other factors, namely, the maximum solubility of furfural in organic solvents, the ΔGsol value of organic solvents in water, and the side reaction of furfural in organic solvents. The degradation rate of furfural in 2-butanol was detected to be the fastest, and molecular dynamics simulation data showed that the hydrogen bonding between furfural and 2-butanol may accelerate the degradation of furfural. DCM has excellent extraction ability for furfural, and the maximum furfural yield in the DCM/H2O system (81.64%) is much higher than that in other systems during the hydrothermal reaction without additional catalysts. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Direct determination of thiomersal in vaccine by atomic fluorescence spectrometry with dielectric barrier discharge (DBD)-plasma induced vaporization was developed. No sample pretreatments other than dilution were needed in the measurement. The evaporation and atomization of thiomersal in vaccine samples was achieved rapidly in one step. The produced mercury vapor was transported to atomic fluorescence spectrometry for analysis. It is a green method that obviates the need of strong oxidization procedure for degradation of thiomersal to inorganic mercury and reduction agents such as sodium tetrahydroborate(iii) or tin(ii) chloride to generate Hg vapor. The DBD plasma was generated in a quartz tube (i.d. 5 mm and o.d. 6 mm) by a concentric circles model. The operating parameters such as discharge gas type, gas flow rate, and power were optimized. Possible interference by concomitant elements was also investigated. External calibration was achieved with aqueous standards solution of thiomersal. Under the optimal experimental condition, the detection limit was 0.03 μg L−1 for Hg, equivalent to 0.06 μg L−1 of thiomersal in solution. The analytical precision, represented by the relative standard deviation (RSD) from multiple measurements (n = 5) of 5 μg L−1 thiomersal (as Hg), was 2.5%. This method was also applied to measure thiomersal in five commercial vaccines. In the absence of CRMs for thiomersal in vaccine samples, it was validated by comparing with results from inductively coupled plasma mass spectroscopy (ICP-MS), which showed good correlation. [ABSTRACT FROM AUTHOR]