A new strategy for PET depolymerization: Application of bimetallic MOF-74 as a selective catalyst

Large-volume production of poly(ethylene terephthalate) (PET), especially in the form of bottles and food packaging containers, causes problems with polymer waste management. Waste PET could be recycled thermally, mechanically or chemically and the last method allows to obtain individual monomers, b...

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Bibliographic Details
Published in:Journal of environmental management 2024-07, Vol.363, p.121360, Article 121360
Main Authors: Baluk, Mateusz Adam, Trzebiatowska, Patrycja Jutrzenka, Pieczyńska, Aleksandra, Makowski, Damian, Kroczewska, Malwina, Łuczak, Justyna, Zaleska-Medynska, Adriana
Format: Article
Language:English
Subjects:
Bimetallic MOF-74
Chemical recycling
Depolymerization of PET
Green catalysts
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Summary:Large-volume production of poly(ethylene terephthalate) (PET), especially in the form of bottles and food packaging containers, causes problems with polymer waste management. Waste PET could be recycled thermally, mechanically or chemically and the last method allows to obtain individual monomers, but most often it is carried out in the presence of homogeneous catalysts, that are difficult to separate and reuse. In view of this, this work reports for the first time, application of bimetallic MOF-74 – as heterogeneous catalyst - for depolymerization of PET with high monomer (bishydroxyethyl terephthalate, BHET) recovery. The effect of type and amount of second metal in the MOF-74 (Mg/M) was systematically investigated. The results showed increased activity of MOF-74 (Mg/M) containing Co2+, Zn2+ and Mn2+ as a second metal, while the opposite correlation was observed for Cu2+ and Ni2+. It was found that the highest catalytic activity was demonstrated by the introduction of Mg–Mn into MOF-74 with ratio molar 1:1, which resulted in complete depolymerization of PET and 91.8% BHET yield within 4 h. Furthermore, the obtained catalyst showed good stability in 5 reaction cycles and allowed to achieve high-purity BHET, which was confirmed by HPLC analysis. The as-prepared MOF-74 (Mg/Mn) was easy to separate from the post-reaction mixture, clean and reuse in the next depolymerization reaction. [Display omitted] •MOF-74 (Mg/M) exhibits catalytic activity in PET depolymerization.•Introducing of Co2+, Zn2+ and Mn2+ into MOF-74 (Mg/M) increases catalytic activity.•MOF-74 (Mg/Mn) causes complete depolymerization of PET and 91.8% recovery of BHET.•MOF-74 (Mg/Mn) shows high efficiency and stability over five PET conversion cycles.
ISSN:0301-4797
1095-8630
1095-8630
DOI:10.1016/j.jenvman.2024.121360