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Kremer I, Tomić T, Katančić Z, Erceg M, Papuga S, Vuković JP, Schneider DR. Catalytic pyrolysis of mechanically non-recyclable waste plastics mixture: Kinetics and pyrolysis in laboratory-scale reactor. J Environ Manage 2021; 296:113145. [PMID: 34271358 DOI: 10.1016/j.jenvman.2021.113145] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Post-consumer waste plastics that cannot be mechanically recycled represent a concerning environmental issue. According to the latest available data for Europe, as much as 25% of collected post-consumer waste plastics are landfilled, 43% is energy recovered, and 32% is recycled. One possible way of recovering non-recyclable plastics is pyrolysis, which is considered environmentally friendly technology for obtaining fuel or chemicals from plastic waste. To tackle the challenge of recovering non-recyclable plastics via pyrolysis, it is necessary to determine their actual composition. Visual separation of collected non-recyclable plastics was performed, and Fourier-transform infrared spectroscopy was used to confirm the accuracy of visual separation. A significant amount of plastics labelled as "other" was found. Since the composition of "other" waste plastics has not been sufficiently investigated, relatively few studies on their pyrolysis have been conducted. Therefore, they were characterised and added to the mixture with other found polymer types of non-recyclable plastics. Thermogravimetric analysis was conducted to determine thermochemical behaviour and kinetic parameters required for laboratory pyrolysis investigation. Kinetic analysis was conducted using the Friedman isoconversional model-free method and non-linear multivariate regression method. The goal of this paper was to analyse the kinetics, determine the product yield and characteristics of the pyrolysis process of non-recyclable plastics over zeolite catalysts. It was found how the decomposition of non-recyclable plastics occurs in two decomposition steps. The activation energy of non-recyclable plastics was 144 kJ/mol in the first stage of decomposition and 262 kJ/mol in the second stage of decomposition. It decreased by 34% and 6.5% after fresh fluid catalytic cracking catalyst was added and 41% and 18.3% with iron-modified Zeolite Socony Mobil-5 catalyst. The yield of condensate was 55% (wax) for the original sample, and it decreased to 50% (wax and oil) and 27% (mostly oil) with fresh fluid catalytic cracking and iron modified Zeolite Socony Mobil-5 catalysts. Processes with catalysts promoted the formation of olefins and aromatic compounds in pyrolytic oil. All pyrolysis products had a high value of higher heating value ranging from 39 MJ/kg to 43 MJ/kg showing good potential for further energy use.
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Affiliation(s)
- Irma Kremer
- University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Ivana Lučića 5, 10 002, Zagreb, Croatia.
| | - Tihomir Tomić
- University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Ivana Lučića 5, 10 002, Zagreb, Croatia.
| | - Zvonimir Katančić
- University of Zagreb, Faculty of Chemical Engineering and Technology, Savska cesta 16, 10 000, Zagreb, Croatia.
| | - Matko Erceg
- University of Split, Faculty of Chemistry and Technology, Ruđera Boškovića 35, 21 000, Split, Croatia.
| | - Saša Papuga
- University of Banja Luka, Faculty of Technology, Bulevar Vojvode Petra Bojovića 1A, 78 000, Banja Luka, Bosnia and Herzegovina.
| | | | - Daniel Rolph Schneider
- University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Ivana Lučića 5, 10 002, Zagreb, Croatia.
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Rizzotto V, Chen D, Tabak BM, Yang JY, Ye D, Simon U, Chen P. Spectroscopic identification and catalytic relevance of NH 4+ intermediates in selective NO x reduction over Cu-SSZ-13 zeolites. Chemosphere 2020; 250:126272. [PMID: 32109703 DOI: 10.1016/j.chemosphere.2020.126272] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/01/2020] [Accepted: 02/18/2020] [Indexed: 05/28/2023]
Abstract
Reduction of harmful nitrogen oxides (NOx) from diesel engine exhausts is one of the key challenges in environmental protection, and can be achieved by NH3-assisted selective catalytic reduction (NH3-SCR) using copper-exchanged chabazite zeolites (i.e. Cu-CHA, including Cu-SSZ-13 and Cu-SAPO-34) as catalysts. Understanding the redox chemistry of Cu-CHA in NH3-SCR catalysis is crucial for further improving the NOx reduction efficiency. Here, a series of Cu-SSZ-13 catalysts with different Cu ion exchange levels were prepared, thoroughly characterized by different techniques such as X-ray diffraction, diffuse reflectance ultraviolet-visible spectroscopy and temperature-programmed desorption using NH3 as a probe molecule, etc., and tested in NH3-SCR reactions under steady-state conditions. In situ studies by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), supplemented with density-functional theory calculations, provided solid evidence for the formation of ammonium ion (NH4+) intermediates resulting from the reduction of Cu2+ to Cu+ by co-adsorbed NH3 and NO molecules on Cu-SSZ-13. Catalytic relevance of the NH4+ intermediates, as demonstrated by an increase of NO conversion over Cu-SSZ-13 pre-treated in NH3/NO atmosphere, can be attributed to the formation of closely coupled Cu+/NH4+ pairs promoting the Cu+ re-oxidation and, consequently, the overall NH3-SCR process. This study thus paves a new route for improving the NH3-SCR efficiency over Cu-CHA zeolite catalyst.
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Affiliation(s)
- Valentina Rizzotto
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074, Aachen, Germany
| | - Dongdong Chen
- Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, 510006, Guangzhou, China; National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, 510006, Guangzhou, China
| | - Björn Martin Tabak
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074, Aachen, Germany
| | - Jia-Yue Yang
- Optics & Thermal Radiation Research Center, Shandong University, 266237, Qingdao, China
| | - Daiqi Ye
- Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, 510006, Guangzhou, China; National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, 510006, Guangzhou, China
| | - Ulrich Simon
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074, Aachen, Germany
| | - Peirong Chen
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074, Aachen, Germany; Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, 510006, Guangzhou, China; National Engineering Laboratory for VOCs Pollution Control Technology and Equipment, 510006, Guangzhou, China.
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