Hierarchically porous carbon derived from pore remodeling of waste polymeric membranes for high-efficiency adsorption applications

•A new approach for the resource utilization of waste PVDF/PET membranes.•The waste membranes are converted into porous carbon by one step carbonization.•KOH promoted the formation of macro-meso-microporous structures of AC-KOH.•The hierarchical pore structure of AC-KOH contributes to the fast mass transfer.•AC-KOH exhibits high adsorption capacity for Congo red (2519.2 mg/g).