Mesoporous and flexible polyimide aerogel as highly active catalytic membrane for AO7 degradation by peroxymonosulfate activation

Zhao, Xinfu; Yi, Xibin; Song, Jialin; Yuan, Xiaoying; Yu, Shimo; Nie, Yihao; Cao, Gege

doi:10.1016/j.cej.2021.134286

Cited by 29 publications

(5 citation statements)

References 59 publications

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“…Figure S3a shows the peaks at 741, 1370, 1500, and 1720 cm –1 , confirming the presence of the imide functional group. The absorption bands at 1720, 1370, and 741 cm –1 correspond to the symmetrical stretching of the CO group, stretching of the C–N in the imide rings and bending of the CO group . The absence of strong peaks at 1620 and 3000 cm –1 indicate that the majority of polyamide acid is imidized.…”

Section: Resultsmentioning

confidence: 99%

“…The absorption bands at 1720, 1370, and 741 cm −1 correspond to the symmetrical stretching of the C�O group, stretching of the C−N in the imide rings and bending of the C�O group. 25 The absence of strong peaks at 1620 and 3000 cm −1 indicate that the majority of polyamide acid is imidized. The absorbance peak at 1500 cm −1 corresponds to the benzene ring, signifying the formation of chains comprised of benzene ring structure.…”

Section: Cross-linking Reactionmentioning

confidence: 99%

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Polyimide Aerogels with Excellent Thermal Insulation, Hydrophobicity, Machinability, and Strength Evolution at Extreme Conditions

Zhang

Wang

et al. 2022

ACS Appl. Polym. Mater.

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High performance polyimide aerogels (PIA) are highly desirable as a part of thermal protection systems for aircraft. However, the large drying shrinkage and insufficient thermal insulation of PIA limit their practical applications in the aerospace field. Herein, the strategy of two-step prepolymerization and polycondensation route was proposed to fabricate PIA with ultralow drying shrinkage, outstanding thermal insulation, hydrophobicity, machinability, compressive strength in cryogenic/high-temperature atmospheres, flame resistance, and fantastic dimensional stability. In more detail, the drying shrinkage rate of PIA series can be lowered to 1.84%, mainly owing to the strengthened skeletons by chemical bond formation and physical entanglement of molecular chains. Excellent thermal insulation is reflected upon keeping an ink drop state as long as 265 s despite placing it on a cold surface with a temperature of −196 °C. PIA-O2B2 are imparted with hydrophobic properties (with water contact angle of 135°) depending on the hydrogen-bonding interaction between polyimide networking chains and 1H,1H,2H,2H-perfluorodecyltriethoxysilane that was introduced. In addition, the exceptional flame retardant is endowed completely, which is attributed to the evidence of the presence of aromatic ring structures in constructing the aerogel. The high-temperature shrinkage rate of PIA series is as low as 4.81% due to the relative small free volume of the molecular chains. Our study would provide a method for designing ultralow drying shrinkage and superb thermal insulation in cryogenic conditions for PIA in aerospace uses.

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Section: Resultsmentioning

confidence: 99%

Section: Cross-linking Reactionmentioning

confidence: 99%

Polyimide Aerogels with Excellent Thermal Insulation, Hydrophobicity, Machinability, and Strength Evolution at Extreme Conditions

Zhang

Wang

et al. 2022

ACS Appl. Polym. Mater.

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“…As presented in Figure , 16 varieties of degradation intermediates in AO7 degradation were conjectured via the mass library. Based on the quenching tests, EPR analysis, TOC result, HR-MS analysis, and relevant literature, – the plausible mechanism of AO7 elimination over the TPP-NO 2 -800/PMS system was suggested in Figure . As the N atom has a higher electronegativity, graphitic N of TPP-NO 2 -800 first obtains electrons from the adjacent C atoms in the TPP-NO 2 -800/PMS process .…”

Section: Results and Discussionmentioning

confidence: 99%

Selective ¹O₂ Generation from Peroxymonosulfate Activation over N-Doped Carbon Nanosponges for Pollutant Degradation

Zhou,

Fang,

Yang

et al. 2023

ACS Appl. Nano Mater.

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Recently, carbon-based nanomaterials have attracted significant attention as promising metal-free nanocatalysts for activating persulfates in wastewater treatment via nonradical oxidative pathways ( 1 O 2 and electron transfer). Herein, a series of N-doped carbon nanosponges have been designed and synthesized by calcination of organic porphyrins as efficient and metal-free nanocatalysts for activating peroxymonosulfate (PMS) on acid orange 7 (AO7) degradation via a nonradical pathway. In this work, the key point of this strategy is the choice of substituent groups (including −OH, −COOH, and −NO 2 ) on 5,10,15,20-tetraphenylporphyrin (TPP), which could serve both the heteroatom-doped source and the morphological conditioning agent. Further studies reveal that the doping of the N atom in carbon nanosponges could greatly improve their catalytic performance for activating PMS on AO7 degradation by regulating the morphology and physicochemical properties. The quenching tests and EPR analysis verified that 1 O 2 , which contributed to 74.0% of total AO7 degradation, is selectively produced from the TPP-NO 2 -800/PMS system without any radicals (e.g., SO 4 •−, O 2•− , and HO • ). The minor contribution (26.0%) for AO7 elimination is probably attributed to electron transfer between AO7 and PMS.

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“…But the mechanical strength of the obtained aerogel is still small. In the synthesis, the addition of TPU will induce an amount of macropores with a size of 2 μm, while the cross-linking of PI aerogel will produce mesopores with a size of 2–50 nm; , the presence of large and small pores will reduce the mechanical strength of the aerogel in theory. Bin Ding et al provided that the aerogel was too fragile to withstand tiny external stress because of the lack of effective bonding among fibers, so constructing of junction points between the fibers of aerogel can enhance its mechanical strength .…”

Section: Introductionmentioning

confidence: 99%

Surface Modification of Polyimide Aerogel by Thermoplastic Polyurethane for Enhanced Mechanical Strength and Thermal Insulation Performance

Zhao,

Su,

et al. 2024

ACS Appl. Mater. Interfaces

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Polyimide (PI) aerogel is a good thermal insulation material with the highest temperature resistance in practical application. But the mechanical strength of PI aerogels prepared by freeze-drying or thermoimide methods is weak. In this research, TPU was selected as an aging solution to solve the problem of the low mechanical strength of PI aerogel prepared by the freeze-drying method. Previous work has certified that the coupling of PI and thermoplastic polyurethane (TPU) can enhance the mechanical strength of PI aerogel to a certain extent due to the flexibility of TPU. But excessive TPU will change the PI structure in the cross-linking process and decrease the mechanical strength of the aerogel. Thus, a new kind of PI gel modification method was provided by using TPU as an aging solution, and the mechanical strength of PI aerogel is improved to 3.06 MPa. Furthermore, the shrinkage, specific surface area, waterproof angle, and thermal conductivity all show good performance, thus enabling PI aerogel to be used in many aspects. Specially, the method is simple and can be used to prepare some other high-strength aerogels.

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Mesoporous and flexible polyimide aerogel as highly active catalytic membrane for AO7 degradation by peroxymonosulfate activation

Cited by 29 publications

References 59 publications

Polyimide Aerogels with Excellent Thermal Insulation, Hydrophobicity, Machinability, and Strength Evolution at Extreme Conditions

Polyimide Aerogels with Excellent Thermal Insulation, Hydrophobicity, Machinability, and Strength Evolution at Extreme Conditions

Selective ¹O₂ Generation from Peroxymonosulfate Activation over N-Doped Carbon Nanosponges for Pollutant Degradation

Surface Modification of Polyimide Aerogel by Thermoplastic Polyurethane for Enhanced Mechanical Strength and Thermal Insulation Performance

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Mesoporous and flexible polyimide aerogel as highly active catalytic membrane for AO7 degradation by peroxymonosulfate activation

Cited by 29 publications

References 59 publications

Polyimide Aerogels with Excellent Thermal Insulation, Hydrophobicity, Machinability, and Strength Evolution at Extreme Conditions

Polyimide Aerogels with Excellent Thermal Insulation, Hydrophobicity, Machinability, and Strength Evolution at Extreme Conditions

Selective 1O2 Generation from Peroxymonosulfate Activation over N-Doped Carbon Nanosponges for Pollutant Degradation

Surface Modification of Polyimide Aerogel by Thermoplastic Polyurethane for Enhanced Mechanical Strength and Thermal Insulation Performance

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Product

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Selective ¹O₂ Generation from Peroxymonosulfate Activation over N-Doped Carbon Nanosponges for Pollutant Degradation