Catalytic Glycolysis of Poly(ethylene terephthalate) Using Zinc and Cobalt Oxides Recycled from Spent Batteries

FUENTES, CYNTHIA A.; GALLEGOS, MARÍA V.; GARCÍA, JUAN R.; SAMBETH, JORGE; PELUSO, MIGUEL A.

Waste and Biomass Valorization

springer

Año: 2019 p. 1 - 13

1877-2641

The chemical recycling of polyethylene terephthalate (PET) to bis(2-hydroxyethyl) terephthalate (BHET) was studied usingrecycled metal oxides. Recovered zinc (RZnO) and cobalt (RCoO) oxides were obtained after a biohydrometallurgical processto recycle spent alkaline and lithium-ion batteries (LIBs), respectively. Besides, a mixed oxide (Co/RZnO) was preparedby mechanical milling of 2.5 wt% of RCoO on RZnO. The structural, textural, and acidity properties of the catalysts wereanalyzed by XRD, XANES, SEM, TEM, FT-IR, SBET and pyridine-TPD. The depolymerization of PET (from soft-drinkbottles) was carried out with ethylene glycol (EG) at 196 °C for 2 h, using PET/catalyst and PET/EG ratios of 100:1 and 1:8,respectively. The yields of the BHET monomer in the presence of RZnO, RCoO and Co/RZnO as catalysts were 50%, 10%and 80%, respectively. The highest catalytic activity of Co/RZnO could be attributed to the presence of weak and strong acidsites, its overall higher concentration of acid sites and a synergetic effect between Co3O4and ZnO. The obtained BHET wascharacterized by DSC, FT-IR, 1H NMR and 13C NMR analyses, which confirmed the purity and structure of the monomer.Metal oxides obtained using spent alkaline and lithium-ion batteries as raw materials could be used as catalysts for wastePET treatment and pure BHET monomer synthesis