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Evolution of nitrogen/oxygen substituted aromatics from sludge to light and heavy volatiles
- Source :
- Journal of Cleaner Production. 257:120327
- Publication Year :
- 2020
- Publisher :
- Elsevier BV, 2020.
-
Abstract
- Thermal treatments of sludge lead to the emission of carcinogenic aromatics, which has already attracted the attention of researchers for years. However, until now the evolution of substituted polycyclic aromatic hydrocarbons (PAHs), especially those with high molecular weight, during thermal treatments of sludge was not paid enough attention even though some of them are more toxic than their parent PAHs. To comprehend the generation of substituted PAHs, in particular that of heavy substituted PAHs, volatiles released from the pyrolysis of three sludge at three temperatures were comprehensively analyzed. The results show oxygen-substituted PAHs (O-PAHs) and nitrogen-substituted PAHs (N-PAHs) are the most abundant light substituted PAHs at 450 °C, while PAHs containing both nitrogen and oxygen atoms (NO-PAHs) and O-PAHs are the dominant substituted aromatics in heavy components. With the temperature increased, condensation degree and content of substituted PAHs in light and heavy components both increase due to condensation effect. Deamination and deoxygenation of NO-PAHs also enhance content of O-PAHs and N-PAHs, respectively. At 850 °C, nearly all heavy components derive from the condensation of light molecules instead of the direct decomposition of sludge. Aromatics, especially N-PAHs, are the dominant compounds in both light and heavy components. Calcium compounds in sludge can greatly affect the formation of substituted PAHs at high temperatures.
- Subjects :
- Renewable Energy, Sustainability and the Environment
020209 energy
Strategy and Management
05 social sciences
Condensation
chemistry.chemical_element
02 engineering and technology
Oxygen
Decomposition
Nitrogen
Industrial and Manufacturing Engineering
chemistry
Environmental chemistry
Calcium Compounds
050501 criminology
0202 electrical engineering, electronic engineering, information engineering
Molecule
Pyrolysis
Deoxygenation
0505 law
General Environmental Science
Subjects
Details
- ISSN :
- 09596526
- Volume :
- 257
- Database :
- OpenAIRE
- Journal :
- Journal of Cleaner Production
- Accession number :
- edsair.doi...........6425afecda70076bc54e1a57c50a9080