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This study focused on evaluating the reduction of chlorine content in waste polyvinyl chloride (WPVC) through high‐temperature catalytic hydrothermal treatment (HTT). Catalytic HTT experiments were carried out to evaluate the effect of noble metal catalysts (Ru/C, Pt/C, and Pd/C), residence time (0.5, 1, 2, and, 4 h), reaction temperature (300, 325, and 350°C), and catalyst loading (0, 5, and 10 wt%). The findings indicated that dechlorination efficiency can be achieved by 99.01% at 350°C and 1 h, with 10 wt% Pd/C loading. Based on chlorine balance, the chlorine content of the solid phase significantly decreased from 568.8 to 5.64 g kg−1 at the same condition. The catalytic HTT solid residue ash has low chlorine content under most operational conditions. These results suggest that catalytic HTT is an effective method to dechlorinate WPVC as a high‐halogenated waste plastic in order to reduce its harmful effect on the environment. [ABSTRACT FROM AUTHOR]

About 40 million tons of plastic waste were produced in the USA in 2021. Waste polyvinyl chloride (WPVC), which is a halogenated material, makes up a significant component of plastic waste. It is vital to design a dependable approach for treating WPVC in a safe and eco-friendly manner without the emission of chlorinated organic chemicals. Dechlorination of WPVC by hydrothermal treatment (HTT) is a viable approach for developing a non-toxic and virtually totally closed WPVC treatment system. According to the literature, noble metal catalysts are often employed to speed HTT. In this study, Pd/C, Ru/C, and Pt/C were used in HTT to promote the dichlorination of WPVC. HTT experiments were carried out using a Hast-C Parr batch reactor at temperatures ranging from 300 to 350 °C for a duration of 0.25 to 4 h. The results indicated that Pd/C, Ru/C, and Pt/C can improve dichlorination efficiency (DE). The maximum DE was 99.1 %, which was achieved at 350 °C and 1 h in the presence of 10 wt% Pd/C. In addition, the HTT solid product has a low chloride content in addition to a high amount of carbon and hydrogen, which results in a much higher heating value (HHV). It indicates that there is a feasible possibility of upcycling WPVC into a clean solid fuel using HTT. [ABSTRACT FROM AUTHOR]