Mechanism of microwave-assisted iron-based catalyst pyrolysis of discarded COVID-19 masks
Waste Management
; 155:77-86, 2023.
Article
in English
| Scopus | ID: covidwho-2246649
ABSTRACT
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. © 2022 Elsevier Ltd
COVID-19; Humans; Hydrogen; Iron; Masks; Microwaves; Pyrolysis; Bamboo; Dielectric properties; Efficiency; Hematite; Microwave heating; ferric oxide; Bamboo-like CNT; Dielectrics property; Discarded medical mask; Disposables; Iron-based catalyst; Microwave pyrolysis; Microwave-assisted; Microwave-assisted pyrolysis; Microwave-heating; ]+ catalyst; carbon nanotube; catalysis; heating; reaction kinetics; temperature; human; mask; microwave radiation; prevention and control; Catalysts; Bamboo-like CNTs; Discarded medical masks
Full text:
Available
Collection:
Databases of international organizations
Database:
Scopus
Language:
English
Journal:
Waste Management
Year:
2023
Document Type:
Article
Similar
MEDLINE
...
LILACS
LIS