Upcycling of real-world HDPE plastic wastes into high-purity methane and hierarchical porous carbon materials: Influence of plastics additives

Zhou et al. converted actual HDPE waste containing calcium carbonate and carbon black additives into methane and hierarchical porous carbon via self-pressurized pyrolysis coupled with KOH activation; methane purity was >93%, HPC specific surface area was 2,785-2,913 m2/g, and HPC supercapacitors showed 301 F/g at 1 A/g, 89.1% capacitance retention at 20 A/g, and 82% capacity retention after 5,000

“Addressing the issue of real-world plastic waste (PWs) containing additives, Zhou and colleagues utilized actual high-density polyethylene (HDPE) plastic waste containing calcium carbonate (CaCO 3 ), and carbon black additives [36] .The conversion of PWs into methane and hierarchical porous carbon (HPC) material was achieved through a self-pressurized pyrolysis process coupled with KOH activation.”

Zhou et al. found that additives had minimal impact on product distribution and methane content but significantly altered the structural morphology and performance of hierarchical porous carbon, increasing mesopores and macropores and surface functional groups while reducing graphitization.

“The study found that although additives had minimal impact on the product distribution and methane content, they significantly altered the structural morphology and performance characteristics of the HPC.The HPC prepared from the additive-containing system showed an increased proportion of mesopores and macropores and richer surface functional groups, but a reduced degree of graphitization.”