| 1. |
- Luo, Dan, et al.
(författare)
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Green, General and Low-cost Synthesis of Porous Organic Polymers in Sub-kilogram Scale for Catalysis and CO2 Capture
- 2023
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Ingår i: Angewandte Chemie International Edition. - : John Wiley & Sons. ; n/a:n/a
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Tidskriftsartikel (refereegranskat)abstract
- Porous organic polymers (POPs) with high porosity and tunable functionalities have been widely studied for use in gas separation, catalysis, energy conversion and energy storage. However, the high cost of organic monomers, and the use of toxic solvents and high temperatures during synthesis pose obstacles for large-scale production. Herein, we report the synthesis of imine and aminal-linked POPs using inexpensive diamine and dialdehyde monomer in green solvents. Theoretical calculations and control experiments show that using meta-diamines is crucial for forming aminal linkages and branching porous networks from [2 + 2] polycondensation reactions. The method demonstrates good generality in that 6 POPs were successfully synthesized from different monomers. Additionally, we scaled up the synthesis in ethanol at room temperature, resulting in the production of POPs in sub-kilogram quantities at a relatively low cost. Proof-of-concept studies demonstrate that the POPs can be used as high-performance sorbents for CO2 separation and as porous substrates for efficient heterogeneous catalysis. This method provides an environmentally friendly and cost-effective approach for large-scale synthesis of various POPs.
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| 2. |
- Xu, Qinqin, et al.
(författare)
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Gold recovery from E-waste using freestanding nanopapers of cellulose and ionic covalent organic frameworks
- 2023
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 458, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- The ever-increasing production of electronic devices generates a huge amount of electronic waste (E-waste). Therefore, there is an urgent need for advanced recycling technology for E-waste that provides both economic and environmental benefits. Herein, we describe the preparation of flexible, freestanding CF-COF nanopapers consisting of cellulose fibers (CFs) and guanidinium-based ionic covalent organic framework (COF) that can be used for recovering gold from E-waste leaching solutions via a membrane separation technique. Due to the synergetic effects of physical adsorption, ion exchange and chemical reduction, the COF has an extremely high capture capacity (up to 1,794 mg of Au per gram of COF), is highly selective and has fast kinetics for adsorbing trace amounts of [AuCl4]− in aqueous solution. The high COF loadings (∌50 wt%) and hierarchical porosity of the CF-COF nanopapers resulted in excellent performance when capturing gold species from the E-waste leaching solution. This study provides new possibilities for developing sustainable membrane materials, and highly efficient and cost-effective techniques for the recovery of precious metals from E-waste.
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| 3. |
- Kong, Xueying, et al.
(författare)
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Ambient Aqueous Synthesis of Imine-Linked Covalent Organic Frameworks (COFs) and Fabrication of Freestanding Cellulose Nanofiber@COF Nanopapers
- 2023
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 146:1, s. 742-751
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Tidskriftsartikel (refereegranskat)abstract
- Covalent organic frameworks (COFs) are usually synthesized under solvothermal conditions that require the use of toxic organic solvents, high reaction temperatures, and complicated procedures. Additionally, their insolubility and infusibility present substantial challenges in the processing of COFs. Herein, we report a facile, green approach for the synthesis of imine-linked COFs in an aqueous solution at room temperature. The key behind the synthesis is the regulation of the reaction rate. The preactivation of aldehyde monomers using acetic acid significantly enhances their reactivity in aqueous solutions. Meanwhile, the still somewhat lower imine formation rate and higher imine breaking rates in aqueous solution, in contrast to conventional solvothermal synthesis, allow for the modulation of the reaction equilibrium and the crystallization of the products. As a result, highly crystalline COFs with large surface areas can be formed in relatively high yields in a few minutes. In total, 16 COFs are successfully synthesized from monomers with different molecular sizes, geometries, pendant groups, and core structures, demonstrating the versatility of this approach. Notably, this method works well on the gram scale synthesis of COFs. Furthermore, the aqueous synthesis facilitates the interfacial growth of COF nanolayers on the surface of cellulose nanofibers (CNFs). The resulting CNF@COF hybrid nanofibers can be easily processed into freestanding nanopapers, demonstrating high efficiency in removing trace amounts of antibiotics from wastewater. This study provides a route to the green synthesis and processing of various COFs, paving the way for practical applications in diverse fields.
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| 4. |
- Kong, Xueying, et al.
(författare)
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Aqueous synthesis and engineering of imine-linked covalent organic frameworks
- 2023
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Ingår i: One-day symposium: Sorption, Transport and Catalysis in Metal-Organic Frameworks. Uppsala 18/9 2023. - Uppsala.
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Konferensbidrag (refereegranskat)abstract
- Covalent organic frameworks (COFs) are typically synthesized through solvothermal methods, which necessitate the use of hazardous organic solvents, elevated reaction temperatures, and intricate procedures. Additionally, their insolubility and inability to melt present substantial challenges in the processing of COFs. In this study, we present an eco-friendly method for synthesizing imine-linked COFs by simply stirring the initial materials in an aqueous solution at room temperature. A key element of this approach involves the pre-activation of aldehyde monomers using acetic acid, significantly enhancing their reactivity in aqueous solutions. This innovative strategy results in the rapid formation of highly crystalline COFs formed at relatively high yields, with substantial surface areas, within minutes. Remarkably, this method performs exceptionally well on a gram-scale, producing highly crystalline and porous COFs in scaled-up reactions.We successfully synthesized a total of 15 COFs using monomers with diverse molecular sizes, geometries, pendant groups, and core structures, underscoring the versatility of this approach. Furthermore, our use of cellulose nanofibers (CNFs) as a substrate during the syntheses allows for the growth of COF nanolayers on the CNF surface. These CNF@COF hybrid nanofibers can be effortlessly transformed into freestanding nanopapers.Significantly, both COF powders and CNF@COF nanopapers exhibit remarkable efficiency in removing trace amounts of antibiotics from wastewater. This research offers a promising avenue for the green synthesis and processing of various COFs, paving the way for practical applications in diverse fields.
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| 5. |
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| 6. |
- Shi, Tianhui, et al.
(författare)
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Postsynthetic amine modification of porous organic polymers for CO2 capture and separation
- 2023
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Ingår i: Journal of Polymer Science. ; n/a:n/a
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Porous organic polymers (POPs) constitute an important class of sorbents studied in various adsorption and separation processes. Their unique properties, including high surface areas, adjustable pore sizes, and surface chemistries make them ideal candidates for CO2 capture. To achieve a high CO2 adsorption capacity and selectivity, particularly at the low partition pressures required for post-combustion CO2 capture or direct capture of CO2 from the atmosphere, incorporating amines onto the polymer frameworks or within the pores has shown much promise. This review provides a comprehensive summary of recent studies on the synthesis and CO2 capture performance of amine-functionalized POPs. The review also provides a detailed discussion of structure-performance relationships, focusing on how the loading amount and amine type influence CO2 capture capacity, CO2/N2 selectivity, heat of adsorption, sorption kinetics, and recyclability of POPs. Additionally, the authors offer their perspective on the challenges associated with the practical implementation of amine-modified POPs for CO2 capture.
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| 7. |
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| 8. |
- Wu, Zheng, et al.
(författare)
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Solar Thermal Swing Adsorption on Porous Carbon Monoliths for High-performance CO2 Capture
- 2023
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Ingår i: Nano Research. - : Springer. - 1998-0124 .- 1998-0000. ; 16:7, s. 10617-10625
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Tidskriftsartikel (refereegranskat)abstract
- Utilizing solar energy for sorbent regeneration during the CO2 swing adsorption processes could potentially reduce CO2 capture costs. This study describes a new technique−solar thermal swing adsorption (STSA) for CO2 capture based on application of intermittent illumination onto porous carbon monolith (PCM) sorbents during the CO2 capture process. This allows CO2 to be selectively adsorbed on the sorbents during the light-off periods and thereafter released during the light-on periods due to the solar thermal effect. The freestanding and mechanically strong PCMs have rich ultramicropores with narrow pore size distributions, displaying relatively high CO2 adsorption capacities and high CO2/N2 selectivities. Given the high CO2 capture performance, high solar thermal conversion efficiency and high thermal conductivity, the PCM sorbents could achieve high CO2 capture rate of up to 0.226 kgCO2 kgcarbon−1 h−1 from a gas mixture of 20v% CO2/80v% N2 under STSA conditions with a light intensity of 1,000 W m−2. In addition, the combination of STSA with the conventional vacuum swing adsorption technique further increases the CO2 working capacity.
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| 9. |
- Xu, Chao, Assistant Professor, 1987-
(författare)
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Green synthesis and processing of porous organic materials
- 2023
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Ingår i: National Polymer Academic Paper Conference 2023. - Wuhan.
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Konferensbidrag (refereegranskat)abstract
- Porous organic materials (POMs), including amorphous porous organic polymers (POPs) and crystalline covalent organic frameworks (COFs), are emerging functional porous materials with unique properties such as high surface areas, tunable porosities, and synthetic diversity. They have attracted significant attention for their potential applications in adsorption, separation, catalysis, energy harvesting, and storage. However, their practical use has been hampered by the high synthesis cost, complicated synthesis procedures, and challenges in material processing.To address these limitations, we have recently developed a cost-effective, environmentally friendly, and scalable method for synthesizing imine and aminal linked POPs using industrially available organic linkers in ethanol/water at room temperature. Additionally, a range of imine linked COFs has been synthesized in aqueous solutions at room temperature. Furthermore, we have employed interweaving and interfacial synthesis techniques to process POMs into freestanding nanopapers, utilizing cellulose fibers as a substrate material. These nanopapers demonstrate potential applications as membranes for the removal of antibiotics from wastewater and the capture of gold ions from electronic waste leaching solutions. These advancements offer new possibilities for large-scale synthesis, processing, and the practical application of POMs.
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| 10. |
- Xu, Chao, Assistant Professor, 1987-
(författare)
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Nanoengineering of porous organic materials by nanocellulose
- 2023
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Ingår i: ICAFPM 2023. - Shanghai : ICAFPM.
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Konferensbidrag (refereegranskat)abstract
- Porous organic materials (POMs), including metal-organic frameworks (MOFs), porous organic polymers (POPs) and covalent organic frameworks (COFs), are emerging functional porous materials with unique properties such as high surface areas, tunable porosities, and synthetic diversity. They have attracted significant interests for their potential applications in adsorption, separation, catalysis, energy harvesting, and storage. However, POMs are usually synthesized as insoluble and infusible powders, posing challenges in processing them into desired shapes and structures. As a result, the practical applications of POMs have been significantly hampered.In order to address this issue, we have recently developed nanoengineering techniques with the assistance of cellulose nanofibers (CNFs) as the flexible substrate to process a range of POMs. For example, the interfacial synthesis enabled the formation of POM nanolayers on the surface of functionalized CNFs. The obtained hybrid CNF@POM nanofibers can be easily processed into freestanding and flexible nanopapers and aerogels. The features of renewability, high surface area, rich surface functionality, nanofibrous structure, good dispensability and processability in water of CNFs make them as excellent substrate or template for processing the POMs. The resulting nanocomposites find applications in flexible electrochemical energy storage, solar thermal energy harvesting, thermal insulation, fire retardancy, and E-waste recycling. These studies provided new routes for overcoming the difficulties in processing various POMs. It is expected that the transfer of knowledge from these studies into the areas of materials design and manufacturing could promote the development of fully sustainable, freestanding functional porous materials for versatile applications.
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