Hydrothermal treatment of polyvinyl chloride: Reactors, dechlorination chemistry, application, and challenges

Insights into the evolution of chemical structure and pyrolysis reactivity of PVC-derived hydrochar during hydrothermal carbonization

“…According to previous studies, the hydrothermal temperature is a key factor affecting PVC dechlorination. 23,40 When the hydrothermal temperature exceeds 200 °C, PVC undergoes signicant dechlorination and structural changes. 28 With a solid-liquid ratio of 1 : 10, hydrothermal temperature of 260 °C, and reaction time of 60 min, PVC is completely carbonized.…”

“…16,22 This technology is of signicant interest due to its potential to fundamentally address the challenges associated with the large-scale transformation of PVC waste into low-chlorine solid products. 5,23,24 The organic chlorine in PVC is converted into easily recoverable watersoluble inorganic chlorine without generating dioxin (PCDD/ Fs). 25 Moreover, high dechlorination efficiencies (DE) can be achieved at relatively mild temperatures.…”

Transforming PVC plastic waste to benzene via hydrothermal treatment in a multi-phase system

“…10,11 At lower pyrolysis temperatures (below 300 °C), the yield of organic products is extremely low. 12,13…”

“…6,7 Regarding hydrothermal treatment, it can remove Cl from PVC under relatively mild conditions (below 300 °C), mainly yielding carbon materials, but there is a lack of attention to the composition and yield of organic products. 8,9 For pyrolysis, PVC can be cracked into aliphatic and aromatic hydrocarbons at high temperatures (above 350 °C), with relatively high yield (about 30%), while the compositions are very complex. 10,11 At lower pyrolysis temperatures (below 300 °C), the yield of organic products is extremely low.…”

“…10,11 At lower pyrolysis temperatures (below 300 °C), the yield of organic products is extremely low. 12,13 Due to the unique structure of PVC molecules, the reaction at low temperature (about 250 °C) can lead to dechlorination and the formation of conjugated polyolefins, primarily following a "zipper" mechanism. 14,15 During the removal of chlorine, the structure of the PVC carbon chain changes and the reaction at low temperature mainly yields aromatic hydrocarbons and carbon materials.…”