Mixed-matrix membranes consisting of Pebax and novel nitrogen-doped porous carbons for CO2 separation

Turning Microstructure in Block Copolymer Membranes: A Facile Strategy to Improve CO2 Separation Performance

To mitigate global climate change, the development of membranes with high CO2 permeability and selectivity is urgently needed. Here, a simple and effective non-solvent-induced microstructure rearrangement (MSR) technique is proposed to enhance the gas separation performance of Pebax 2533 membranes. By immersing Pebax 2533 membranes in amino acid salt solutions to induce MSR, the CO2 permeability of the optimized Pebax 2533-GlyK 10 wt.% membrane reached 1180 Barrer, a 4.5-fold increase compared to the original membrane, without compromising CO2/N2 selectivity. Moreover, the MSR membrane maintains stable gas separation performance for nearly 500 days, demonstrating excellent long-term stability. Furthermore, applying the MSR technique to thin-film composite (TFC) membranes revealed that both Pebax 2533/polyvinyl chloride (PVC) hollow fiber (HF) TFC membranes and Pebax 2533/polyacrylonitrile (PAN) flat-sheet TFC membranes exhibited significantly enhanced CO2 permeance under the treatment of DI water. Characterization results indicated that the chemical-physical properties of the membranes before and after MSR are nearly unchanged, suggesting that the non-solvent-induced MSR is a promising technique for next-generation membrane development for carbon capture.

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.

Improved CO2/N2 separation performance of Pebax-1074 blend membranes containing poly(ethylene glycol)

Developing blend membrane material is one feasible and effective route for improving the gas separation efficiency and commercial attractiveness of membrane technologies. Here, free-standing membranes were prepared by casting method using Pebax-1074 as continuous polymer matrix and poly(ethylene glycol) (PEG) as dispersive organic fillers. The morphology, surface functional groups, microstructure and thermal stability of the membranes were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry, respectively. The effects of preparation variables including average molecular weight and dosage of PEG on the microstructure, morphology and properties of the blend membranes were investigated. In addition, the effects of operation conditions including permeation temperature and permeation pressure on the gas separation performance of the blend membranes were also examined. The results showed that the addition of PEG can obviously modify the structure-properties and significantly improve the separation performance of resultant membranes. Under the conditions of 30°C and 0.25 MPa, the optimal CO2 permeability and CO2/N2 selectivity respectively reached to 124.3Barrer and 115.8 for the blend membranes made by PEG600 with a content of 20% in Pebax-1074 matrix. In brief, the as-prepared blend membranes are proved to be promising for CO2/N2 separation application.