Effect of marine ambient in the production of pollutants from the pyrolysis and combustion of a mixture of plastic materials

Highlights: • A mixture of 4 plastics was submerged in seawater for 12 months. The chlorine content and the NCV were periodically measured. • Thermal properties of these plastics were affected by the contact with the marine water. PET was the most affected polymer. • Pyrolysis and combustion runs were carried out. Emission of gases, PAHs, ClBzs, ClPhs, BrPhs, PCBs and PCDD/Fs were studied. • Pollutant emissions are higher when the content of oxygen in the process is lower. • Emissions of chlorinated species are not affected by the chlorine content. The production of PCBs and PCDD/Fs was very low. - Abstract: A mixture of polyethylene (PE), polyethylene-terephtalate (PET), polypropylene (PP) and Nylon was submerged in marine water during 12 moths. The chlorine content of these plastics was measured through the passing time. Thermobalance was used to look for differences in the thermal decomposition of the plastics during in that time interval. Degradation of PET, PP and Nylon produced changes in the weight loss curve, but behaviour of PE is confusing. Pyrolysis and combustion at 850 °C was finally performed to get knowledge of the possible differences in the emission of main gases, volatiles and semivolatiles including polycyclic aromatic hydrocarbons (PAHs), polychlorinated benzenes (ClBzs), polychlorinated phenols (ClPhs), polybrominated phenols (BrPhs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Results show that the emission of chlorinated species is somewhat not affected by the chlorine content of the plastics mix. The production of PCBs and PCDD/Fs was very low, under 4 pg WHO-TEQ/g.