Post-consumer PET Bottle Recycling: Chemical Dose Optimization

Abstract

Polyethylene terephthalate (PET) bottles are being used in our daily life and consequently go to the landfills after their use. Additionally, virgin PET resins are produced from nonrenewable resources, such as fossil fuels, whose reserves are depleting continuously. Therefore, to maintain ecological and environmental balances as well as for sustainable development, post-consumer PET (pcrPET) bottles should be recycled. Among many recycling processes, mechanical recycling of pcrPET is attractive due to lower cost involvement. One of the most crucial and important processes of mechanical recycling is hot washing for contaminants removal. Hot washing uses a cleaning solution made of caustic soda (NaOH) and detergent at elevated temperature. In this paper, caustic soda and FORYL LFO (FLO) detergent doses were changed gradually to investigate effective contaminants removal through colorimetric study. Finally, concentration vs. absorbance graphs from colorimetric study suggests that 2% NaOH and 2% FLO detergent is the optimum chemical dose at hot washing for pcrPET recycling.