A microporous polymer TFC membrane with 2-D MOF nanosheets gutter layer for efficient H2 separation

Highly Efficient CO2/C2H2 Separation by Porous Graphene via Quadrupole Gating Mechanism

Acetylene (C₂H₂) is an important and widely used raw material in various industries (such as petrochemical). Generally, a product yield is proportional to the purity of C₂H₂; however, C₂H₂ from a typical industrial gas-production process is commonly contaminated by CO₂. So far, the achievement of high-purity C₂H₂ separated from a CO₂/C₂H₂ mixture is still challenging due to their very close molecular dimensions and boiling temperatures. Taking advantage of their quadrupoles with opposite signs, here, we show that the graphene membrane embedded with crown ether nanopores can achieve an unprecedented separation efficiency of CO₂/C₂H₂. Combining the molecular dynamics simulation and the density functional theory (DFT) approaches, we discovered that the electrostatic gas-pore interaction favorably allows the fast transport of CO₂ through crown ether nanopores while completely prohibiting C₂H₂ transport, which yields a remarkable permeation selectivity. In particular, the utilized crown ether pore is capable of allowing the individual transport of CO₂ while completely rejecting the passage of C₂H₂, independent of the applied pressures, fed gases ratios, and exerted temperatures, featuring the superiority and robustness of the crown pore in CO₂/C₂H₂ separation. Further, DFT and PMF calculations demonstrate that the transport of CO₂ through the crown pore is energetically more favorable than the transport of C₂H₂. Our findings reveal the potential application of graphene crown pore for CO₂ separation with outstanding performance.

Double-Layered Pebax® 3533/ZIF-8 Membranes with Single-Walled Carbon Nanotube Buckypapers as Support for Gas Separation

Single-walled carbon nanotube buckypapers (SWCNT-bps) coated with a metal-organic framework ZIF-8 layer were used as supports for the preparation of Pebax^® 3533 TFC membranes by both phase inversion and spin coating techniques. Upon proper characterization of the materials by X-ray diffraction, IR spectroscopy, thermogravimetry and electron microscopy, the obtained membranes were tested in gas separation experiments with a 15:85 CO₂/N₂ mixture. These experiments proved that the ZIF-8 layer prevented from the penetration of the polymer selective film into the SWCNT-bp support, giving rise to a highly permeable selective membrane. The optimum membrane was achieved by the spin-coating method, with better permeation results than that prepared by the phase inversion method, obtaining a CO₂ permeance of 566 GPU together with a CO₂/N₂ selectivity of 20.9.

Single-walled carbon nanotube gutter layer supported ultrathin zwitterionic microporous polymer membrane for high-performance lithium-sulfur battery

Development of efficient lithium-sulfur (Li-S) battery requires the need to develop an appropriate functional separator that allows strong facilitation and transport of lithium ions together with limited passage of polysulfides. In this work, a multifunctional separator (TB-BAA/SWCNT/PP) is developed through spin coating of a novel zwitterionic microporous polymer (TB-BAA) on the gutter layer constructed from single-walled carbon nanotubes (SWCNT), where commercially available polypropylene (PP) separator is used to act as the mechanical support. SWCNT in this study serves as the first modification layer to decrease the size of the macropores in the PP separator, while the ultrathin TB-BAA top barrier layer with the presence of zwitterionic side chains allows the creation of confined ionic channels with both lithiophilic and sulfophilic groups. Due to the presence of available chemical interactions with lithium polysulfides, selective ion transport can be foreseen through such separator. In this regard, shuttle effect that is frequently encountered in Li-S battery can be suppressed effectively via implementing the as-obtained functional separator, resulting in the creation of credible and stable sulfur electrochemistry. The TB-BAA/SWCNT/PP-based Li-S battery has been investigated to possess high cycling ability (capacity fading per cycle of 0.055% over 500 cycles at 1 C) together with decent rate capability (736.6 mAh g^-1 at 3 C). In addition, a high areal capacity retention of 5.03 mAh cm^-2 after 50 cycles can be also obtained under raised sulfur loading (5.4 mg cm^-2).

Advanced strategies for enhancing dark fermentative biohydrogen production from biowaste towards sustainable environment

As a clean energy carrier, hydrogen is a promising alternative to fossil fuel so as the global growing energy demand can be met. Currently, producing hydrogen from biowastes through fermentation has attracted much attention due to its multiple advantages of biowastes management and valuable energy generation. Nevertheless, conventional dark fermentation (DF) processes are still hindered by the low biohydrogen yields and challenges of biohydrogen purification, which limit their commercialization. In recent years, researchers have focused on various advanced strategies for enhancing biohydrogen yields, such as screening of super hydrogen-producing bacteria, genetic engineering, cell immobilization, nanomaterials utilization, bioreactors modification, and combination of different processes. This paper critically reviews by discussing the above stated technologies employed in DF, respectively, to improve biohydrogen generation and stating challenges and future perspectives on biowaste-based biohydrogen production.

Amino-functionalized Cu metal-organic framework nanosheets as fluorescent probes for detecting TNP

Here, we report a simple and benign method to successfully fabricate amino-functionalized Cu metal-organic framework (NH₂-Cu-MOF) nanosheets. After synthesizing Cu₂O nanocubes, they were mixed with organic ligand 2-aminoterephthalic acid (NH₂BDC) solution at room temperature for 4 hours to form NH₂-Cu-MOF nanosheets. Interestingly, the prepared NH₂-Cu-MOF nanosheets have ultra-thin thickness, directional growth characteristics and excellent crystallinity. Moreover, such nanosheets showed high-intensity and high-stability fluorescence emission under excitation. As TNP in water can quench the fluorescence emission of the fluorescent probe, the NH₂-Cu-MOF nanosheet fluorescent probe was established for detecting TNP in water with high sensitivity and selectivity, which is very useful for assessing the environmental quality and safety of water bodies. Finally, the probe was used to detect TNP in actual samples with good recovery rate.