Ionic liquid enhancement of interface compatibility in mixed-linker ZIF-based mixed matrix membranes for advanced CO2/CH4 separation

Mixed matrix membranes (MMMs) are highly promising for natural gas sweetening due to their high microporosity and outstanding gas separation performance. However, MMMs are frequently challenged by the polymer/filler interfacial incompatibility, leading to the deterioration of gas separation performance. In this study, the mixed-linker ZIF-7-8 was employed as a filler by finely tuning the molecular sieving for CO2/CH4 separation. An amino-functionalized ionic liquid ([C(3)NH(2)Mim][Cl]) was introduced for constructing the interface connection between the ZIF-7-8 filler and polymer matrix through coordination and hydrogen bonding, which was verified by extended X-ray absorption fine structure (EXAFS) and electron paramagnetic resonance (EPR). The design of interface interaction through an IL is crucial to improve the interface compatibility and the CO2/CH4 separation performance. The newly developed 20% ZIF-7-8-IL (1%)/PI and 25% ZIF-7-8-IL (1%)/PI MMMs displayed a dramatic improvement of CO2 permeability by 244.2% and 291.6%, from 308 to 1060 and 1206 barrer, respectively, for pure-gas separation, compared to the pristine polyimide matrix. Moreover, the 25% ZIF-7-8-IL (1%)/PI MMM also demonstrated outstanding low-temperature mixed-gas CO2/CH4 separation performance in the temperature range of -45-35 degrees C, far beyond the 2018 mixed-gas CO2/CH4 upper bound

Unzipping MWCNTs for controlled edge- and heteroatom-defects in revealing their roles in gas-phase oxidative dehydrogenation of ethanol to acetaldehyde

Bioethanol is a promising candidate for acetaldehyde production. In this study, we controllably unzipped multi-walled carbon nanotubes into open-edged nanotube/nanoribbon hybrids via a nano-cutting strategy for metal-free oxidative dehydrogenation of ethanol to acetaldehyde and unravelled the catalytic role of edge defects in the reaction. The edge-rich structure of the 1D-nanotube/2D-nanoribbon hybrid can accelerate the catalytic reaction more efficiently than pristine carbon sample. Moreover, edges can further accommodate nitrogen defects to preferentially form edge-doped nitrogen. Through engineering the concentration and speciation of defects, the structure-performance relationship between the defective structure and ethanol conversion rate is intensively investigated. Theoretical calculations unveil that the nitrogen doped at edge sites other than in basal planes can effectively facilitate O2 dissociation and formation of oxygen-containing active centers. Temperature-programmed ethanol desorption and kinetic measurements further supplement the catalytic interplay of edge and nitrogen defects on ethanol adsorption and reaction kinetics. The synergistic edge and nitrogen defects of the engineered hybrid produced a steady ethanol conversion of 47.9% and acetaldehyde selectivity of 90.2% at the gas hourly space velocity of 48,000 mL gcat-1h−1 on stream of 48 h. This work offers more insights to intrinsic properties and mechanism of enriched defective structures for development of effective carbocatalysts in catalytic applications

Ionic liquid enhancement of interface compatibility in mixed-linker ZIF-based mixed matrix membranes for advanced CO2/CH4 separation

Mixed matrix membranes (MMMs) are highly promising for natural gas sweetening due to their high microporosity and outstanding gas separation performance. However, MMMs are frequently challenged by the polymer/filler interfacial incompatibility, leading to the deterioration of gas separation performance. In this study, the mixed-linker ZIF-7-8 was employed as a filler by finely tuning the molecular sieving for CO2/CH4 separation. An amino-functionalized ionic liquid ([C(3)NH(2)Mim][Cl]) was introduced for constructing the interface connection between the ZIF-7-8 filler and polymer matrix through coordination and hydrogen bonding, which was verified by extended X-ray absorption fine structure (EXAFS) and electron paramagnetic resonance (EPR). The design of interface interaction through an IL is crucial to improve the interface compatibility and the CO2/CH4 separation performance. The newly developed 20% ZIF-7-8-IL (1%)/PI and 25% ZIF-7-8-IL (1%)/PI MMMs displayed a dramatic improvement of CO2 permeability by 244.2% and 291.6%, from 308 to 1060 and 1206 barrer, respectively, for pure-gas separation, compared to the pristine polyimide matrix. Moreover, the 25% ZIF-7-8-IL (1%)/PI MMM also demonstrated outstanding low-temperature mixed-gas CO2/CH4 separation performance in the temperature range of -45-35 degrees C, far beyond the 2018 mixed-gas CO2/CH4 upper bound

Fluonanobody-based nanosensor via fluorescence resonance energy transfer for ultrasensitive detection of ochratoxin A

Ochratoxin A (OTA) contamination in food is a serious threat to public health. There is an urgent need for development of rapid and sensitive methods for OTA detection, to minimize consumer exposure to OTA. In this study, we constructed two OTA-specific fluonanobodies (FluoNbs), with a nanobody fused at the carboxyl-terminal (SGFP-Nb) or the amino-terminal (Nb-SGFP) of superfolder green fluorescence protein. SGFP-Nb, which displayed better fluorescence performance, was selected as the tracer for OTA, to develop a FluoNb-based nanosensor (FN-Nanosens) via the fluorescence resonance energy transfer, where the SGFP-Nb served as the donor and the chemical conjugates of OTA-quantum dots served as the acceptor. After optimization, FN-Nanosens showed a limit of detection of 5 pg/mL, with a linear detection range of 5-5000 pg/mL. FN-Nanosens was found to be highly selective for OTA and showed good accuracy and repeatability in recovery experiments using cereals with various complex matrix environments. Moreover, the contents of OTA in real samples measured using FN-Nanosens correlated well with those from the liquid chromatography with tandem mass spectrometry. Therefore, this work illustrated that the FluoNb is an ideal immunosensing tool and that FN-Nanosens is reliable for rapid detection of OTA in cereals with ultrahigh sensitivity