This　work　developed　a　novel　oxidized　hierarchical　porous　carbon　(OHPC)　with　vesicule-like　ultrathin　graphitic　walls　via　a　method　of　air　oxidation　and　used　as　an　efficient　adsorbent　for　Congo　red　(CR)　and　Malachite　green　(MG)　removal.　Results　show　that　the　OHPC2　oxidized　at　400　°C　possesses　three-dimensional　hierarchical　pores　with　vesicule-like　ultrathin　graphitic　walls.　The　prepared　OHPC2　not　only　has　a　large　specific　surface　area　of　1020　m2　g−1　with　a　high　pore　volume,　but　also　has　abundant　oxygen-containing　functional　groups.　These　unique　structural　features　endow　the　OHPC2　with　high　adsorption　capacities　for　CR　(2729.5　mg　g−1)　and　MG　(1697.3　mg　g−1)　removal.　The　adsorption　processes　of　CR　and　MG　are　in　accordance　with　the　Langmuir　isotherm　and　Quasi-second-order　kinetic　models.　The　thermodynamic　studies　illustrate　that　the　adsorption　processes　were　thermodynamically　feasible　and　spontaneous.　Various　characterization　analysis　explained　that　the　adsorption　mechanism　may　involve　pore-filling　effect,　π-π　conjugation,　hydrogen　bonding,　and　electrostatic　attraction.　Moreover,　the　OHPC2　exhibits　good　cycling　stability　and　is　identified　as　a　desirable　adsorbent　for　actual　wastewater　treatment.　©　2024　Elsevier　Inc.