From waste polyvinyl chloride to activated carbons: the role of occurring additives on porosity development and gas adsorption properties

<p> Conversion of waste plastic to carbon materials has been considered as a potential approach for plastic recycling. In this study, <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/polyvinyl-chloride" target="_blank">polyvinyl chloride</a> (PVC) plastic, one of the most widely used polymers, was used as a single precursor to prepare porous carbons via chemical activation process. The results showed that KOH activation followed by acid washing was an effective strategy to recover all calcium- and up to 92% of titanium-based compounds, the main metal additives in PVC, in the form of soluble salt. Those metal additives in PVC acted as a type of hard template, which benefit the development of <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/microporosity" target="_blank">microporosity</a> and carbon dioxide (CO2) adsorption. Textural characterization demonstrated that the prepared carbons possessed high surface area and pore volume of up to 2507 m2/g and 1.11 cm3/g, respectively. At 0 °C and 100 kPa, the PVC-derived carbon, PH_73, which has highest ultra-micropore volume among all samples, exhibited excellent CO2 adsorption capacity of 6.90 mmol/g and high CO2/N2 <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/selectivity" target="_blank">selectivity</a>. Converting the non-degradable PVC into high-quality porous carbon materials could be considered as a potential strategy for plastic waste recycling. </p>