Advancing carbon capture with bio-inspired membrane materials: A review

Dong H., Wang Y., Ding W., Qiu Y., He H.

Li S., Zhang H., Lu Z., Cao F., Wang Z., Liu Y., Zhu X., Ning S., Miao K., Qiu S., Li D.

Ceramic matrix composites (CMCs) structural components encounter the dual challenges of severe mechanical conditions and complex electromagnetic environments due to the increasing demand for stealth technology in aerospace field. To address various functional requirements, this study integrates a biomimetic strategy inspired by gradient bamboo vascular bundles with a novel dual-material 3D printing approach. Three distinct bamboo-inspired structural configurations Cf/SiC composites are designed and manufactured, and the effects of these different structural configurations on the CVI process are analyzed. Nanoindentation method is utilized to characterize the relationship between interface bonding strength and mechanical properties. The results reveal that the maximum flexural strength and fracture toughness reach 108.6±5.2 MPa and 16.45±1.52 MPa·m1/2, respectively, attributed to the enhanced crack propagation resistance and path caused by the weak fiber-matrix interface. Furthermore, the bio-inspired configuration enhances the dielectric loss and conductivity loss, exhibiting a minimum reflection loss of -24.3 dB with the effective absorption band of 3.89 GHz. This work introduces an innovative biomimetic strategy and 3D printing method for continuous fiber-reinforced ceramic composites, expanding the application of 3D printing technology in the field of CMCs.

Behera D.K., Wang F., Sengupta B., Friedman K., Li S., Yu M.

Li P., Sun Y., Zhang Z., Gu Z., Qiao Z., Zhong C.

Metal-organic frameworks (MOFs) have driven the development of polycrystalline membranes in the field of gas separation owing to the strong adsorption-desorption behavior and stable framework structure. However, the poor heterogeneous bonding ability between crystals and the substrate leads to the unsatisfactory gas separation as well as low stability of MOF membranes, especially in the humid environment. Herein, we prepared a thin and defect-free UiO-66 membrane by a crystal heterogeneous nucleation assisted growth strategy for efficient CO2/N2 separation. The addition of small amount of water in the precursor solution promoted the crystal nucleation process on the substrate surface. Meanwhile, the smooth PDMS interlayer guaranteed the heterogeneous well-intergrown of crystals into thin UiO-66 membranes, and provided a hydrophobic environment. Therefore, the dense UiO-66 membrane with a small thickness exhibited a high CO2 permeance (177.4 × 10−9 mol·m−2·s−1·Pa−1) with moderate CO2/N2 selectivity (24.3) under humid conditions. Furthermore, the prepared membrane demonstrated excellent renewable performance after dehumidification at high temperature, and maintained good hydrothermal stability during long-term operation under the humid environment. This work provides a new insight for the design of high-quality MOF membranes and promotes the development of MOF membranes in practical gas separation process.

Dai Y., Fang T., Li S., Wang Y., Zhong S., Su W., Li J.

Zhang K., Li S., Tian X., Zhang R., Feng X., Wang Q., Tang Y., Liu C., Gao H., Wang S.

Wang J., Li L., Wang Z., Zhang J., Li X.

Zhang L., Zhao Y., Yu H., Chen L., Liu X., Zhang A., Deng Z., Ou J.Z.

Graphene oxide (GO) membranes hold promise for selective CO2 adsorption over N2 due to their carboxyl groups, making them attractive for flue gas CO2 capture. However, challenges such as limited carboxyl content, flexible nanosheets, and dense layer stacking hinder their N2/CO2 gas selectivity, pressure resistance, and permeability. In this study, we introduce a specific sub-nanometer framework structure within GO membranes by in-situ growing ZIF-8 nanocrystals. This novel approach, achieved through simultaneous infiltration of zinc nitrate and 2-methylimidazole precursors on both sides of the membrane, enhances CO2 capture and pressure resistance capabilities of resulting ZIF-8@GO composite membranes. Additionally, the incorporation of carboxylated wrinkled graphene (WG) and ethylenediamine (EDA) cross-linking agent molecules improves CO2 capture capability and introduces reinforced porous structures to enhance permeability. Experimental results demonstrate remarkable permeability, selectivity, and pressure resistance of the prepared ZIF-8@EDA-GO/WG composite membranes. Under a gas pressure of 0.2 MPa, permeability reaches 1850 GPU, with theoretical selectivity for N2/CO2 single gas and separation factors for mixed gases of 18.3 and 32.3, respectively, surpassing conventional GO membranes (3 GPU, 1.1, and 1.2). Even under elevated air pressure conditions (1.2 MPa), the composite membranes maintain a theoretical selectivity of 13.4. Our CO2 capture membrane design strategy not only advances the development of functional membranes but also contributes to mitigating CO2 emissions from flue gas, thereby combating global warming.

Ma Z., Chen X., Jia M., Mao H., Li M., Zhou S., Xin J.H., Zhao Y.

Enhancing the wetting resistance of the membrane is crucial for consolidating the stability of the membrane distillation (MD) process, but this generally leads to the decline of water vapor flux. Herein, we developed a superhydrophobic composite membrane composed of a highly hydrophobic polyvinylidene fluoride (PVDF) porous support layer and a functional superhydrophobic carbon nanotubes (CNTs) network. The CNTs network with high thermal conductivity not only reduces the temperature polarization effect, but also increases the effective evaporation area, thereby enhancing the mass transfer driving force of the MD process. Additionally, the CNTs network significantly reduces the maximum pore radius of the composite membrane, and the perfluorination treatment also reduces the surface energy of the CNTs network, thereby synergistically increasing the liquid entry pressure. The results showed that when treating high salinity water containing 3.5 wt% NaCl, the water vapor flux of the composite membrane increased from 20.0 LMH of the original PVDF membrane to 24.4 LMH, an increase of 22 %. Furthermore, the performance of the original PVDF membrane deteriorates rapidly when the concentration of surfactant in the feed exceeds 1.0 mM, while the composite membrane still maintains a stable water vapor permeability and salt rejection. More importantly, the composite membrane exhibits excellent resistance to wetting induced by gypsum scaling when using gypsum solution as the feed, which is attributed to its small surface pore size and high hydrophobicity. This research supplies new insights into the design of membrane structures used in MD processes to overcome the trade-off between water vapor permeability and wetting resistance.

Zhou Z., Cao X., Lv D., Cheng F.

The use of metal–organic frameworks (MOFs) in gas separation has been widely explored. However, the stabilities are poor in various practical applications, especially under humid conditions. In this work, water-stable UiO-66-(CF3)2 was prepared by grafting with trifluoromethyl groups. On this basis, mixed matrix membranes (MMMs) containing different UiO-66-(CF3)2 loadings in PIM-1 were fabricated. When the UiO-66-(CF3)2 loading was increased from 0 to 8 %, the CO2 permeability of the membrane increased from 3265 to 5242 Barrer, and the CO2/N2 selectivity improved from 24.2 to 33.8. Meanwhile, we prepared the PIM-UF/PDMS/PSf (PUPP) composite membranes and applied for CO2/N2 separation under humid conditions. Specifically, PUPP-8 % exhibited a permeability of 1111 GPU and a competitive CO2/N2 separation factor of 43.78 under the simulated flue gas environment (57 °C, 0.1 MPa, 10 vol% H2O), which transcended the 2008 upper bound. Finally, we studied the long-term gas permeability to simulate the real flue gas environment, and the PUPP-8 % water content test conditions maintained its structure and performance, benefiting from good water stability. These results demonstrated that improving the water stability of MOFs and developing high-performance membranes for stabilization in high-humidity environments is a potentially effective strategy.

Pedrozo H.A., Panagakos G., Biegler L.T.

López L.R., Dessì P., Cabrera-Codony A., Rocha-Melogno L., Kraakman N.J., Balaguer M.D., Puig S.

Direct air capture (DAC) is a promising technology that can help to remove carbon dioxide (CO2) from the air. One application of DAC is indoor CO2 direct air capture (iCO2-DAC). A wide range of materials with unique properties for CO2 capture have been investigated, including porous materials, zeolites, and metal-organic frameworks. The selection of suitable materials for iCO2-DAC depends on several factors, such as cost, CO2 adsorption capacity, and stability. The development of new materials with improved properties for iCO2-DAC is an active research area. The captured CO2 can serve as a renewable carbon source to produce biofuels for internal use (e.g., for heating purposes), decreasing the environmental impact of buildings. This review article highlights the importance of iCO2-DAC to improve indoor air quality in buildings and boost the circular economy. We discuss the available carbon capture technologies and materials, discussing their properties and focusing on those potentially applicable to indoor environments. We also provide a hypothetic scenario where CO2 is captured from different indoor environments and transformed into sustainable fuels by using an emerging carbon capture and utilization technology (microbial electrosynthesis). Finally, we evaluate the economic feasibility of such an innovative approach in comparison to the use of traditional, fossil-based fuels.

Wang L., Zha S., Zhang S., Jin J.

AbstractCapturing carbon dioxide (CO2) from flue gases is a crucial step towards reducing CO2 emissions. Among the various carbon capture methods, facilitated transport membranes (FTMs) have emerged as a promising technology for CO2 capture owing to their high efficiency and low energy consumption in separating CO2. However, FTMs still face the challenge of losing mobile carriers due to weak interaction between the carriers and membrane matrix. Herein, we report a sulfonated chitosan (SCS) gel membrane with confined amine carriers for effective CO2 capture. In this structure, diethylenetriamine (DETA) as a CO2‐mobile carrier is confined within the SCS gel membrane via electrostatic forces, which can react reversibly with CO2 and thus greatly facilitate its transport. The SCS ion gel membrane allows for the fast diffusion of amine carriers within it while blocking the diffusion of nonreactive gases, like N2. Thus, the prepared membrane exhibits exceptional CO2 separation capabilities when tested under simulated flue gas conditions with CO2 permeance of 1155 GPU and an ultra‐high CO2/N2 selectivity of above 550. Moreover, the membrane retains a stable separation performance during the 170 h continuous test. The excellent CO2 separation performance demonstrates the high potential of gel membranes for CO2 capture from flue gas.

Ali J., Faridi S., Kashyap A., Shabnam, Noori R., Sardar M.

The utilisation of carbonic anhydrase (CA) in CO2 sequestration is becoming prominent as an efficient, environment friendly and rapid catalyst for capturing CO2 from industrial emissions. However, the application of CA enzyme in soluble form is constrained due to its poor stability in operational conditions of CO2 capture and also production cost of the enzyme. Addressing these limitations, the present study focuses on the surface display of CA from Bacillus halodurans (BhCA) on E coli aiming to contribute to the cost-effectiveness of carbon capture through CA technology. This involved the fusion of the BhCA-encoding gene with the adhesion molecule involved in diffuse adherence (AIDA-I) autotransporter, resulting in the efficient display of BhCA (595 ± 60 U/gram dry cell weight). Verification of the surface display of BhCA was accomplished by conjugating with FITC labelled anti-his antibody followed by fluorescence-activated cell sorting (FACS) and cellular fractionation in conjunction with zymography. Biochemical characterisation of whole-cell biocatalyst revealed a noteworthy enhancement in thermostability, improvement in the thermostability with T1/2 of 90 ± 1.52 minutes at 50 ˚C, 36 ± 2.51 minutes at 60 ˚C and18 ± 1.52 minutes at 80˚C. Surface displayed BhCA displayed remarkable reusability retaining 100% activity even after 15 cycles. Surface displayed BhCA displayed highly alkali stable nature like free counterpart in solution. The alkali stability of the surface-displayed BhCA was comparable to its free counterpart in solution. Furthermore, the study investigated the impact of different metal ions, modulators, and detergents on the whole-cell biocatalysts. The present work represents the first report on surface display of CA utilising the AIDA-1 autotransporter.

Yu Z., Guo Z., Yu L., Feng X., Wang B.