Investigation of Rapid Chemical Recycling of Waste Polyethylene Terephthalate Under Microwave Effect Using Calcined Dolomite as Catalyst

Abstract

According to the United Nations, our planet produces an average of 430 million tons of plastic annually. A significant portion of the environmental pollution caused by the use of plastics is due to polyethylene terephthalate (PET) used in short-lived packaging products. Various studies have been conducted with the aim of recycling or converting PET waste into useful products. In addressing the dual environmental challenges posed by waste PET and dolomite, this study innovates in the realm of sustainable recycling practices. We explore the efficiency of a solid catalyst derived from waste dolomite in catalyzing the hydrolysis of waste PET. This research not only showcases the catalytic prowess of waste-derived dolomite in breaking down PET into its constituent monomers but also highlights the process’s optimization for maximum efficiency. Through careful analysis and optimization of various parameters, including Temperature, reaction time, and catalyst concentration, we achieve an unprecedented conversion rate, illustrating the potential of this method in contributing to the circular economy. Our findings offer a groundbreaking approach to PET waste management, emphasizing the importance of sustainability and innovation in tackling environmental pollution. Dolomite is a widely available ore with a composition of CaCO3.MgCO3. After calcination, the obtained CaO-MgO mixture can be used to recycle PET via hydrolysis. In this study, Temperature (140 °C, 150 °C, 160 °C), ethanol concentration (0%, 5%, 10%), potassium hydroxide concentration (0%, 5%, and 10%), and the amount of calcined dolomite (0 g/100 mL, 0.03 g/100 mL, and 0.06 g/100 mL) parameters were selected for the PET hydrolysis process conducted in a short time using a microwave digestion system. The Taguchi L9 experimental design was applied, and all experiments were repeated four times.