Uniformly Distributed Mixed Matrix Membranes via a Solution Processable Strategy for Propylene/Propane Separation.

Aggregation of filler particles during the formation of mixed matrix membranes is difficult to avoid when filler loadings exceed a 10-15 wt %. Such agglomeration usually leads to poor membrane performance. In this work, using a ZIF-67 metal-organic framework (MOF) as filler along with surface modification of Ag tz to improve processability and selective olefin adsorption, we demonstrate that highly loaded with a very low agglomeration degree membranes can be synthesized displaying unmatched separation selectivity (39) for C H /C H mixtures and high permeability rates (99 Barrer), far surpassing previous reports in the literature.

Amidoxime modified polymers of intrinsic microporosity/alginate composite hydrogel beads for efficient adsorption of cationic dyes from aqueous solution.

Polymers of intrinsic microporosity (PIM-1) has demonstrated great potential in adsorption and separation fields. In this study, PIM-1 was structured into an applicable and efficient adsorbent using a facile way. PIM-1 was first modified by amidoxime, and then the amidoxime modified PIM-1 (AOPIM-1) was mingled into alginate (Alg) hydrogel to obtain composite hydrogel beads.

Moderately Crystalline Azine-Linked Covalent Organic Framework Membrane for Ultrafast Molecular Sieving.

Covalent organic frameworks are potential candidates for the preparation of advanced molecular separation membranes due to their porous structure, uniform aperture, and chemical stability. However, the fabrication of continuous COF membranes in a facile and mild manner remains a challenge. Herein, a continuous, defect-free, and flexible azine-linked ACOF-1 membrane was prepared on a hydrolyzed polyacrylonitrile (HPAN) substrate via interfacial polymerization (IP).

High-Performance Polybenzimidazole Membranes for Helium Extraction from Natural Gas.

Increasing helium use in research and production processes necessitates separation techniques to secure sufficient supply of this noble gas. Energy-efficient helium production from natural gas is still a big challenge. Membrane gas separation technology could play an important role.

Facile manufacture of porous organic framework membranes for precombustion CO capture.

The development of new membranes with high H separation performance under industrially relevant conditions (high temperatures and pressures) is of primary importance. For instance, these membranes may facilitate the implementation of energy-efficient precombustion CO capture or reduce energy intensity in other industrial processes such as ammonia synthesis. We report a facile synthetic protocol based on interfacial polymerization for the fabrication of supported benzimidazole-linked polymer membranes that display an unprecedented H/CO selectivity (up to 40) at 423 K together with high-pressure resistance and long-term stability (>800 hours in the presence of water vapor).

One-Pot Synthesis of High-Flux b-Oriented MFI Zeolite Membranes for Xe Recovery.

We demonstrate that b-oriented MFI (Mobil Five) zeolite membranes can be manufactured by in situ crystallization using an intermediate amorphous SiO layer. The improved in-plane growth by using a zeolite growth modifier leads to fusion of independent crystals and eliminates boundary gaps, giving good selectivity in the separation of CO/Xe mixtures. The fast diffusion of CO dominates the overall membrane selectivity toward the CO/Xe mixture.

Molecular-Scale Hybrid Membranes Derived from Metal-Organic Polyhedra for Gas Separation.

The preparation and the performance of mixed matrix membranes based on metal-organic polyhedra (MOPs) are reported. MOP fillers can be dispersed as discrete molecular units (average 9 nm in diameter) when low filler cargos are used. In spite of the low doping amount (1.

Nanosheets of Nonlayered Aluminum Metal-Organic Frameworks through a Surfactant-Assisted Method.

During the last decade, the synthesis and application of metal-organic framework (MOF) nanosheets has received growing interest, showing unique performances for different technological applications. Despite the potential of this type of nanolamellar materials, the synthetic routes developed so far are restricted to MOFs possessing layered structures, limiting further development in this field. Here, a bottom-up surfactant-assisted synthetic approach is presented for the fabrication of nanosheets of various nonlayered MOFs, broadening the scope of MOF nanosheets application.

Enhanced vapour sensing using silicon nanowire devices coated with Pt nanoparticle functionalized porous organic frameworks.

Recently various porous organic frameworks (POFs, crystalline or amorphous materials) have been discovered, and used for a wide range of applications, including molecular separations and catalysis. Silicon nanowires (SiNWs) have been extensively studied for diverse applications, including as transistors, solar cells, lithium ion batteries and sensors. Here we demonstrate the functionalization of SiNW surfaces with POFs and explore its effect on the electrical sensing properties of SiNW-based devices.

Azine-Linked Covalent Organic Framework (COF)-Based Mixed-Matrix Membranes for CO2 /CH4 Separation.

Mixed-matrix membranes (MMMs) comprising Matrimid and a microporous azine-linked covalent organic frameworks (ACOF-1) were prepared and tested in the separation of CO2 from an equimolar CO2 /CH4 mixture. The COF-based MMMs show a more than doubling of the CO2 permeability upon 16 wt % ACOF-1 loading together with a slight increase in selectivity compared to the bare polymer. These results show the potential of COFs in the preparation of MMMs.

Tunable hydrogen separation in porous graphene membrane: first-principle and molecular dynamic simulation.

First-principle density functional theory (DFT) calculation and molecular dynamic (MD) simulation are employed to investigate the hydrogen purification performance of two-dimensional porous graphene material (PG-ESX). First, the pore size of PG-ES1 (3.2775 Å) is expected to show high selectivity of H2 by DFT calculation.

Self-assembly of double helical nanostructures inside carbon nanotubes.

We use molecular dynamics (MD) simulations to show that a DNA-like double helix of two poly(acetylene) (PA) chains can form inside single-walled carbon nanotubes (SWNTs). The computational results indicate that SWNTs can activate and guide the self-assembly of polymer chains, allowing them to adopt a helical configuration in a SWNT through the combined action of the van der Waals potential well and the π-π stacking interaction between the polymer and the inner surface of SWNTs. Meanwhile both the SWNT size and polymer chain stiffness determine the outcome of the nanostructure.

Influence of chemical functionalization on the CO₂/N₂ separation performance of porous graphene membranes.

The separation of CO₂ from a mixture of CO₂ and N₂ using a porous graphene membrane was investigated using molecular dynamics (MD) simulations. The effects of chemical functionalization of the graphene sheet and pore rim on the gas separation performance of porous graphene membranes were examined. It was found that chemical functionalization of the graphene sheet can increase the absorption ability of CO₂, while chemical functionalization of the pore rim can significantly improve the selectivity of CO₂ over N₂.