As a consequence of the widespread use of polyethylene terephthalate (PET), huge amounts of PET waste are generated annually, and thus a critical point of waste management strategy is to reduce these amounts. This study presents the chemical recycling of PET waste using sub- and supercritical water (SubCW and SCW). Two types of PET waste were chosen to study hydrolytic depolymerization: colorless and colored bottles. The experiments were carried out in a batch reactor at temperatures from 250 to 400??C, with reaction period of 1?30?min. During the hydrolysis of PET waste, primary and secondary products were formed. The highest yield of terephthalic acid (TPA) was identified at 300??C and a reaction period of 30?min; 90.0???0.4% yield was observed from colorless PET waste and 85.0???0.2% from green PET waste. The purity of final TPA obtained from PET waste was near 100%. The formation of secondary products such as benzoic acid, 1,4-dioxane, acetaldehyde, isophthalic acid (IPA) and carbon dioxide (CO2) were detected.

» Author: Maja ?olnik, ?eljko Knez, Mojca ?kerget

» Publication Date: 06/04/2021

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