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.
Colorimetric study of traditional varnishes applied on paper exposing to aging tests
