Decomposition of poly(vinyl chloride) in inductively coupled radiofrequency thermal plasma

• PVC can be decomposed effectively by RF thermal plasma technology.
• Soot formation depends on plate power and gas composition.
• HCl is the sole chlorine containing molecule that could be detected in gas phase.
• Oxygen containing aromatic compounds, like dioxins or furans were not detected.
• In oxidative atmosphere polychlorinated PAHs can be formed.

Decomposition of poly(vinyl chloride) (PVC) was studied in inductively coupled radiofrequency thermal plasma in neutral, oxidative and reductive conditions. The exhaust gases were analysed by Fourier transform infrared spectroscopy (FT-IR), and their main components were identified as CO, CO2, C2H2, H2O and HCl. The weaker bands in the infrared spectra were assigned by density function theory calculations and P–R separation method. The extent of PVC decomposition was calculated from the amount of solid soot, which was also studied by transmission electron microscopy (TEM) for morphology and composition. Organic compounds adsorbed on the surface of the soot were extracted by toluene and analysed by gas chromatography mass spectrometry (GC/MS). The extracts comprised of various polycyclic aromatic hydrocarbons (PAHs) and their methylated and chlorinated derivatives. Their amount was greatly affected by the experimental conditions. The presence of oxygen decreased the formation of PAHs, while it increased the formation of polychlorinated PAH compounds. In the presence of hydrogen PAH formation was observed. However, dioxin or furan derivatives were not detected in the decomposition products.