Exploring NH3 Transport Properties by Tailoring Ionic Liquids in Pebax-Based Hybrid Membranes

Advanced Materials for NH3 Capture: Interaction Sites and Transport Pathways

Ammonia (NH3) is a carbon-free, hydrogen-rich chemical related to global food safety, clean energy, and environmental protection. As an essential technology for meeting the requirements raised by such issues, NH3 capture has been intensively explored by researchers in both fundamental and applied fields. The four typical methods used are (1) solvent absorption by ionic liquids and their derivatives, (2) adsorption by porous solids, (3) ab-adsorption by porous liquids, and (4) membrane separation. Rooted in the development of advanced materials for NH3 capture, we conducted a coherent review of the design of different materials, mainly in the past 5 years, their interactions with NH3 molecules and construction of transport pathways, as well as the structure-property relationship, with specific examples discussed. Finally, the challenges in current research and future worthwhile directions for NH3 capture materials are proposed.

Enhancement strategies of poly(ether-block-amide) copolymer membranes for CO2 separation: A review

Poly(ether-block-amide) (Pebax) membranes have become the preferred CO2 separation membrane because of their excellent CO2 affinity and robust mechanical resistance. Nevertheless, their development must be considered to overcome the typical obstacles in polymeric membranes, including the perm-selectivity trade-off, plasticization, and physical aging. This article discusses the recent enhancement strategies as a guideline for designing and developing Pebax membranes. Five strategies were developed in the past few years to improve Pebax gas transport properties, including crosslinking, mobile carrier attachment, polymer blending, filler incorporation, and the hybrid technique. Among them, filler incorporation and the hybrid technique were most favorable for boosting CO2/N2 and CO2/CH4 separation performance with a trade-off-free profile. On the other hand, modified Pebax membranes must deal with two latent issues, mechanical strength loss, and perm-selectivity off-balance. Therefore, exploring novel materials with unique structures and surface properties will be promising for further research. In addition, seeking eco-friendly additives has become worthwhile for establishing Pebax membrane sustainable development for gas separation.

Pathway for Water Transport through Breathable Nanocomposite Membranes of PEBAX with Ionic Liquid [C12C1im]Cl

Water transport through membranes is an attractive topic among the research dedicated to dehydration processes, microenvironment regulation, or more simply, recovery of freshwater. Herein, an atomistic computer simulation is proposed to provide new insights about a water vapor transport mechanism through PEBAX membranes filled with ionic liquid (IL) [C12C1im]Cl. Starting from experimental evidence that indicates an effective increase in water permeation as the IL is added to the polymer matrix (e.g., up to 85·10-3 (g·m)/(m2·day) at 318.15 K for PEBAX@2533 membranes loaded with 70% of IL), molecular dynamics simulations are proposed to explore the key role of IL in water transport inside membranes. The polar region composed of anions and cationic head groups of the IL is demonstrated to serve as the pathway for water transport through the membrane. Water molecules always stay near the pathway, which becomes wider and thus has a larger water-accessible area with increasing IL concentration. Hence, the diffusion coefficients of water molecules and ions increase as the IL concentration increases. The simulation provides useful indications about a microscopic mechanism that regulates the transport of water vapor through a kind of PEBAX/IL membrane, resulting in full agreement with the experimental evidence.