How to upcycle PVC waste and produce bioethanol

Polyvinyl chloride (PVC) is durable and holds up against moisture and corrosion. That makes it a good plastic for pipes, construction material, and medical devices. But its high chlorine content also makes it challenging to recycle.

A synergistic process that combines PVC pyrolysis with bioethanol production provides a practical use for PVC waste (Cell Rep. Phys. Sci. 2025, DOI: 10.1016/j.xcrp.2025.102514). The approach does not produce new plastic. Instead, it upcycles the waste PVC into valuable products such as synthetic liquid fuel, char, and syngas—a key feedstock for industrial processes.

PVC is recycled today at much lower rates than other plastics, and most of the millions of metric tons of PVC waste are sent to landfills or incinerated each year. Incinerating PVC releases toxic hydrogen chloride (HCl) gas, and in landfills, chlorine compounds can leach into soil and groundwater, says Jaewon Lee, a professor of battery and chemical engineering at Hanyang University.

Lee and colleagues found a clever use for the HCl: as an input for bioethanol production. First, the researchers pyrolyze PVC at 390 °C, producing HCl and a residue containing mainly polyene structures. They siphon the HCl away for a bioethanol-making process in which it breaks down shredded hay via acid hydrolysis. Multiple hay hydrolysis steps give sugars that they ferment to produce ethanol.

Next, the team tosses the biomass residue and PVC polyene residue into another pyrolysis reactor. This time, the researchers pipe in carbon dioxide, and in its presence the pyrolysis produces syngas, oil, and char.

The researchers reuse the oil, which is primarily composed of polycyclic aromatic hydrocarbons, as a fuel to heat the system. The total value of the other products plus the bioethanol “exceeds the installation and operating costs of the process, providing a clear economic advantage over existing recycling methods,” Lee says. Additionally, the process consumes about 7,000 kg of CO₂ per 40,000 kg of PVC residue and biomass residue. This CO₂ can be captured from industrial plants, making the process a meaningful application for utilizing captured carbon.

“This process provides an innovative way to extract value from PVC and biowaste,” says Yosi Kratish, a chemist at Northwestern University. Shifting the focus toward chemical transformation of PVC is valuable although it’s not traditional recycling, which aims to regenerate new PVC, he says, and the method has real-world potential. A large-scale facility would require significant investment, given the sophisticated equipment and complex operation needed. Mixed, contaminated waste plastic streams would also pose a challenge, he says. “If these challenges can be addressed, this approach could be a valuable addition to waste management and biofuel production strategies.”