Usability of waste plastic pyrolysis liquid/oil as a flotation collector in wastewater treatment

Pyrolysis is an important thermal waste disposal method that is more environmentally friendly than the combustion process, and almost all of its products can be converted into economic value. Specifically, the pyrolysis oils obtained are evaluated in different areas, such as the production of next-generation fuels and the recovery of valuable materials. Wastewater released during marble processing should not be discharged into the sewer without treatment, in accordance with national and international legislation, due to the high concentration of colloidal substances it contains. In the treatment of these wastewaters, conventional chemical precipitation processes and high amounts of synthetic chemicals are commonly used. Another method that can be employed for treating these wastewaters is the chemical substance-assisted flotation process, where efficiency depends on the use of oil-based chemicals. In this study, the treatment of marble processing wastewater was carried out for the first time using the flotation process, with pyrolysis oils obtained from mixed plastic waste pyrolysis as the collector material. According to the treatment experiments, the flotation collector that showed the highest suspended solid (SS) and turbidity removal efficiency was the pyrolysis oil obtained at a pyrolysis temperature of 700 °C. The flotation treatment findings were modeled using experimental design, and it was also revealed that collector dosage, mixing speed and air flow rate significantly affected the removal efficiencies.