Dual-Modulated Polyamide Membranes Based on Vapor–Liquid Interfacial Polymerization for CO₂ Separation

Polyamide (PA) membranes show great application potential in the CO2 separation study. However, the PA membranes prepared by the traditional interfacial polymerization (IP) have a dense microstructure and a singularity of functional groups, making it difficult to exhibit both high CO2 permeance and selectivity. Herein, we report a new dual-modulation strategy by preparation method optimization and filler modification to improve the CO2 separation performance of the PA membranes. The PA membranes prepared by vapor–liquid IP have a loose microstructure, which greatly improves the gas permeance. The introduction of mono-(6-ethanediamine-6-deoxy)-beta-cyclodextrin (CD) can better loosen the PA microstructure, and the CO2-philic groups in the CD boost the CO2 selectivity by the facilitated transport effect. Ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate is further sealed into PA membranes to remedy the possible microvoids or defects and CD cavities of the membrane microstructure. The prepared membranes display excellent CO2 separation performance with CO2/H2, CO2/CH4, and CO2/N2 selectivity of 8.2, 45.5, and 116.9, as well as a CO2 permeance of about 320 GPU. The proposed strategy provides a facile and effective route to dual-modulated PA membranes for the study of CO2 separation and can be expanded to other macrocyclic molecules and ionic liquid systems

Single-Hole Hollow Carbon Nanospheres via a Poly(ethylene glycol)-Assisted Emulsion-Templating Strategy for Intensified Liquid-Phase Adsorption

Single-hole hollow carbon nanospheres (HCH) possess unique properties that combine the advantages of a hollow cavity and an opening hole in the shell, making them very attractive in various applications. However, it is still a challenge to synthesize HCH via a facile and scalable route. Herein, we develop a poly­(ethylene glycol) (PEG)-assisted emulsion-templating method to synthesize HCH, involving only a hydrothermal process and pyrolysis. In the emulsion system, the PEG molecules can be used as a reverse demulsifier to induce the formation of hollow structures with a closed shell (HCS, PEG-1000), a single hole in the shell (HCH, PEG-2000), and a bowl-like shell (HCB, PEG-4000). It is found that HCH exhibits higher adsorption capacities (2–4 times higher than those of HCS) and faster adsorption rates toward large molecules (e.g., Congo red), indicating the intensification of liquid-phase adsorption induced by the single-hole hollow structure, which can promote mass transfer and simultaneously enhance the adsorption capacity

Polarized Micropores in a Novel 3D Metal–Organic Framework for Selective Adsorption Properties

A novel 3D porous metal–organic framework with 1D polarized channels was synthesized, and its adsorption properties for gas separation and chemical sensing were studied. The framework shows a preferential adsorption of CO2 over N2 with a selectivity of 22:1. It also exhibits a very good sensitivity to water with respect to most of the organic solvents in view of chemical sensing applications

Polarized Micropores in a Novel 3D Metal–Organic Framework for Selective Adsorption Properties

A novel 3D porous metal–organic framework with 1D polarized channels was synthesized, and its adsorption properties for gas separation and chemical sensing were studied. The framework shows a preferential adsorption of CO2 over N2 with a selectivity of 22:1. It also exhibits a very good sensitivity to water with respect to most of the organic solvents in view of chemical sensing applications