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

Abstract

Conversion of waste plastic to carbon materials has been considered as a potential approach for plastic recycling. In this study, polyvinyl chloride (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 microporosity 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 selectivity. Converting the non-degradable PVC into high-quality porous carbon materials could be considered as a potential strategy for plastic waste recycling.