Mechanism of microwave-assisted iron-based catalyst pyrolysis of discarded COVID-19 masks
Copyright © 2022 Elsevier Ltd. All rights reserved.
| Veröffentlicht in: | Waste management (New York, N.Y.). - 1999. - 155(2023) vom: 01. Jan., Seite 77-86 |
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| Weitere Verfasser: | , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2023
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| Zugriff auf das übergeordnete Werk: | Waste management (New York, N.Y.) |
| Schlagworte: | Journal Article Bamboo-like CNTs Dielectric properties Discarded medical masks Iron-based catalyst Microwave-assisted pyrolysis Iron E1UOL152H7 ferric oxide 1K09F3G675 mehr... |
| Zusammenfassung: | Copyright © 2022 Elsevier Ltd. All rights reserved. Inexpensive iron-based catalysts are the most promising catalysts for microwave pyrolysis of waste plastics, especially a large number of disposable medical masks (DMMs) with biological hazards produced by spread of COVID-19. However, most synthesized iron-based catalysts have very low microwave heating efficiency due to the enrichment state of iron. Here, we prepared FeAlOx catalysts using the microwave heating method and found that the microwave heating efficiency of amorphous iron and hematite is very low, indeed, these materials can hardly initiate pyrolysis at room temperature, which limits the application of iron-based catalysts in microwave pyrolysis. By contrast, a mixture of DMMs and low-valent iron oxides produced by hydrogen reduction at 500 °C can be heated by microwaves to temperatures above 900 °C under the same conditions. When the hydrogen reduction temperature was incerased to 800 °C, the content of metallic iron in the catalyst gradually increased from 0.34 to 21.43%, which enhanced the microwave response ability of the catalyst, and decreased the gas content in the pyrolysis product from 78.91 to 70.93 wt%; corresponding hydrogen yield also decreased from 29.03 to 25.02 mmolH2·g-1DMMs. Moreover, the morphology of the deposited solid carbon gradually changed from multi-walled CNTs to bamboo-like CNTs. This study clarifies the pyrolysis mechanism of microwave-assisted iron catalysts and lays a theoretical foundation for their application in microwave pyrolysis |
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| Beschreibung: | Date Completed 29.11.2022 Date Revised 29.11.2022 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1879-2456 |
| DOI: | 10.1016/j.wasman.2022.10.041 |