Preparation and characterization of terephthalic acid from PET plastic waste via low-temperature alkaline hydrolysis

This study presents a comprehensive investigation into the preparation and characterization of terephthalic acid from polyethylene terephthalate (PET) waste using low-temperature alkaline hydrolysis. The significance of this research lies in developing a sustainable and efficient method for recycling plastic waste, contributing to environmental pollution reduction, and promoting the circular economy concept.Low-temperature alkaline hydrolysis (80 °C) was employed to depolymerize PET into its basic units. Reaction conditions, including the molar ratio of (PET: NaOH), reaction time, and water to ethanol ratio in the solvent, were optimized to maximize the yield and quality of TPA. The final product was characterized using spectroscopic analysis techniques such as Fourier transform infrared spectroscopy (FTIR), Proton Nuclear Magnetic Resonance ( 1 H NMR) spectroscopy, and Gas Chromatography-Mass Spectrometry (GC-MS). Results demonstrated that the proposed method effectively produces high-purity terephthalic acid from PET waste with a yield of 99.5 % under the optimum conditions: (PET: NaOH) 1:4, water-to-ethanol ratio (20:80) at 80 °C, and a reaction time of 1 h. Moreover, the aqueous solution can be reused for multiple reaction cycles, enhancing process efficiency and reducing chemical and water consumption. This approach offers a sustainable PET recycling and resource recovery solution.