A robust binary supramolecular organic framework (SOF) with high CO2 adsorption and selectivity

A robust binary hydrogen-bonded supramolecular organic framework (SOF-7) has been synthesized by solvothermal reaction of 1,4-bis-(4-(3,5-dicyano-2,6 dipyridyl)dihydropyridyl)benzene (1) and 5,5’-bis-(azanediyl)-oxalyl-diisophthalic acid (2). Single crystal X-ray diffraction analysis shows that SOF-7 comprises 2 and 1,4-bis-(4-(3,5-dicyano-2,6-dipyridyl)pyridyl)benzene (3), the latter formed in situ from the oxidative dehydrogenation of 1. SOF-7 shows a three-dimensional four-fold interpenetrat-ed structure with complementary O−H···N hydrogen bonds to form channels that are decorated with cyano- and amide-groups. SOF-7 exhibits excellent thermal stability and sol-vent and moisture durability, as well as permanent porosity. The activated desolvated material SOF-7a shows high CO2 sorption capacity and selectivity compared with other po-rous organic materials assembled solely through hydrogen bonding

Polymer nanofilms with enhanced microporosity by interfacial polymerization

Highly permeable and selective membranes are desirable for energy-efficient gas and liquid separations. Microporous organic polymers have attracted significant attention in this respect owing to their high porosity, permeability, and molecular selectivity. However, it remains challenging to fabricate selective polymer membranes with controlled microporosity which are stable in solvents. Here we report a new approach to designing crosslinked, rigid polymer nanofilms with enhanced microporosity by manipulating the molecular structure. Ultra-thin polyarylate nanofilms with thickness down to 20 nm were formed in-situ by interfacial polymerisation. Enhanced microporosity and higher interconnectivity of intermolecular network voids, as rationalised by molecular simulations, are achieved by utilising contorted monomers for the interfacial polymerisation. Composite membranes comprising polyarylate nanofilms with enhanced microporosity fabricated in-situ on crosslinked polyimide ultrafiltration membranes show outstanding separation performance in organic solvents, with up to two orders of magnitude higher solvent permeance than membranes fabricated with nanofilms made from noncontorted planar monomers

Pyrene Bearing Azo-Functionalized Porous Nanofibers for CO2 Separation and Toxic Metal Cation Sensing

This article describes the construction of a novel luminescent azo-linked polymer from 1,3,6,8-tetra(4--aminophenyl)pyrene using a copper(I)-catalyzed oxidative homocoupling reaction

Nitrogen-Rich Porous Polymers for Carbon Dioxide and Iodine Sequestration for Environmental Remediation

The use of fossil fuels for energy production is accompanied by carbon dioxide release into the environment causing catastrophic climate changes. Meanwhile, replacing fossil fuels with carbon-free nuclear energy has the potential to release radioactive iodine during nuclear waste processing and in case of a nuclear accident. Therefore, developing efficient adsorbents for carbon dioxide and iodine capture is of great importance. Two nitrogen-rich porous polymers (NRPPs) derived from 4-bis-(2,4-diamino-1,3,5-triazine)-benzene building block were prepared and tested for use in CO₂ and I₂ capture. Copolymerization of 1,4-bis-(2,4-diamino-1,3,5-triazine)-benzene with terephthalaldehyde and 1,3,5-tris­(4-formylphenyl)­benzene in dimethyl sulfoxide at 180 °C afforded highly porous NRPP-1 (SA_BET = 1579 m² g^–1) and NRPP-2 (SA_BET = 1028 m² g^–1), respectively. The combination of high nitrogen content, π-electron conjugated structure, and microporosity makes NRPPs very effective in CO₂ uptake and I₂ capture. NRPPs exhibit high CO₂ uptakes (NRPP-1, 6.1 mmol g^–1 and NRPP-2, 7.06 mmol g^–1) at 273 K and 1.0 bar. The 7.06 mmol g^–1 CO₂ uptake by NRPP-2 is the second highest value reported to date for porous organic polymers. According to vapor iodine uptake studies, the polymers display high capacity and rapid reversible uptake release for I₂ (NRPP-1, 192 wt % and NRPP-2, 222 wt %). Our studies show that the green nature (metal-free) of NRPPs and their effective capture of CO₂ and I₂ make this class of porous materials promising for environmental remediation

Effective Approach for Increasing the Heteroatom Doping Levels of Porous Carbons for Superior CO₂ Capture and Separation Performance

Development of efficient sorbents for carbon dioxide (CO₂) capture from flue gas or its removal from natural gas and landfill gas is very important for environmental protection. A new series of heteroatom-doped porous carbon was synthesized directly from pyrazole/KOH by thermolysis. The resulting pyrazole-derived carbons (PYDCs) are highly doped with nitrogen (14.9–15.5 wt %) as a result of the high nitrogen-to-carbon ratio in pyrazole (43 wt %) and also have a high oxygen content (16.4–18.4 wt %). PYDCs have a high surface area (SA_BET = 1266–2013 m² g^–1), high CO₂ <i>Q</i>_st (33.2–37.1 kJ mol^–1), and a combination of mesoporous and microporous pores. PYDCs exhibit significantly high CO₂ uptakes that reach 2.15 and 6.06 mmol g^–1 at 0.15 and 1 bar, respectively, at 298 K. At 273 K, the CO₂ uptake improves to 3.7 and 8.59 mmol g^–1 at 0.15 and 1 bar, respectively. The reported porous carbons also show significantly high adsorption selectivity for CO₂/N₂ (128) and CO₂/CH₄ (13.4) according to ideal adsorbed solution theory calculations at 298 K. Gas breakthrough studies of CO₂/N₂ (10:90) at 298 K showed that PYDCs display excellent separation properties. The ability to tailor the physical properties of PYDCs as well as their chemical composition provides an effective strategy for designing efficient CO₂ sorbents