Nanostructured micro particles as a low-cost and sustainable catalyst in the recycling of PET fiber waste by the glycolysis method

Journal article, 2021

Magnetic Mg-Al-O@Fe3O4 micro particles were synthesized by coating nanosized Mg-Al double oxides
onto Fe3O4 micro particles. The formed hierarchical structure gave Mg-Al-O@Fe3O4 micro particles a high
active surface area, which enabled these micro particles to work efficiently as a catalyst in the glycolysis
of poly(ethylene terephthalate) (PET). The bis(hydroxyethyl) terephthalate (BHET) yield reached above
80 mol% in the presence of 0.5 wt% of Mg-Al-O@Fe3O4 micro catalyst in the reaction system within
90 min at 240
C. After the reaction, Mg-Al-O@Fe3O4 micro catalyst was easily retrieved by a magnetic
decantation and can be repetitively used for two times with a high catalytic efficiency. After that, the
deactivated Mg-Al-O@Fe3O4 micro catalyst can be regenerated by heat treatment. The regenerated Mg-
Al-O@Fe3O4 micro catalyst displays a comparable catalytic performance as that of the virgin catalyst.
In addition, the Mg-Al double oxides and Fe3O4 micro particles are low-cost and environmentally benign.
Therefore, the Mg-Al-O@Fe3O4 micro catalyst may contribute to an economically and environmentally
improved large-scale circular recycling of PET fiber waste.