Synthesis of graphene oxide from post-consumer PET bottles by a one-step thermal treatment in air atmosphere for removal of methylene blue

Abstract

Post-consumer polyethylene terephthalate (PET) bottles are promising raw materials to produce value-added materials. This work uses a simple thermal treatment (TT) in an air atmosphere to transform post-consumer PET (PET-W) into graphene-oxide-like material (GOL). A careful analysis of the thermogravimetric (TGA) curves allowed us to determine the optimal temperature for controlling the oxidative decomposition reactions of PET-W at 412 °C while maximizing the bidimensional character of the products. The products of thermal transformation were characterized by Raman spectroscopy, DRX, FTIR, SEM, EDS, XPS, and BET. The results of the characterization indicate the obtaining of a material (identified here as GOLPET) which is characterized by an ID/IG ratio of 0.61, the presence of oxygenated groups such as CO, C-O-C and phenyls at the interphase, and an elemental composition of ∼83.7 (wt.%) and ∼16.27% of carbon and oxygen (wt.%), respectively. XPS allowed us to determine the formation of assembled aromatic chains (Csp2 = 61.53%) and acyclic chains (Csp3=38.47%). Finally, GOLPET absorption capacity was explored for a commercial application such as removing methylene blue (MB dye); complete elimination of MB (99.6%) in an aqueous solution was demonstrated. Considering the annual generation of plastic waste ∼300 million t, the methodology developed in this research can be envisage as an affordable and innovative alternative to produce GO-like materials.