Pyrolysis and catalytic pyrolysis as a recycling method of waste CDs originating from polycarbonate and HIPS

• Thermal and catalytic pyrolysis is a powerful method for recycling of WEEEs.
• Liquid products obtained from the pyrolysis of PC or HIPS found in waste CDs are very different.
• Mainly phenols are obtained from pyrolysis PC based wastes while aromatics from HIPS.
• Use of MgO catalyst increases the amount of phenols from CD recycling compared to ZSM-5.
• Use of MgO or ZSM-5 catalysts reduces the amount of styrene recovered from HIPS.

Pyrolysis appears to be a promising recycling process since it could convert the disposed polymers to hydrocarbon based fuels or various useful chemicals. In the current study, two model polymers found in WEEEs, namely polycarbonate (PC) and high impact polystyrene (HIPS) and their counterparts found in waste commercial Compact Discs (CDs) were pyrolysed in a bench scale reactor. Both, thermal pyrolysis and pyrolysis in the presence of two catalytic materials (basic MgO and acidic ZSM-5 zeolite) was performed for all four types of polymers. Results have shown significant recovery of the monomers and valuable chemicals (phenols in the case of PC and aromatic hydrocarbons in the case of HIPS), while catalysts seem to decrease the selectivity towards the monomers and enhance the selectivity towards other desirable compounds.