Powder　adsorbents　present　limited　recyclability　when　used　for　wastewater　treatment.　Bulk　materials　prepared　via　eco-friendly　approaches　typically　exhibit　excellent　reproducibility　over　powders　in　terms　of　removing　pollutants　from　aquatic　environments.　Here,　biomass-based　aerogels　were　synthesized　via　ball　milling　a　mixture　of　modified　moxa　ash　(a　type　of　moxibustion　waste),　carbon　nanotubes　and　ammonia,　combined　with　agarose　as　biomolecule.　The　obtained　aerogels　display　low　density,　high　porosity,　remarkable　mechanical　properties,　and　exceptional　repeatability　and　stability　for　removing　organic　pollutants.　By　employing　a　two-dimensional　(2D)　aerogel　membrane,　pollutants　such　as　10　mg/L　mitoxantrone　(MTX),　5　mg/L　methylene　blue,　5　mg/L　malachite　green,　or　5　mg/L　rhodamine　B　could　be　dynamically　adsorbed　and　swiftly　filtered　out,　achieving　nearly　100　%　of　the　removal　rate.　For　three-dimensional　(3D)　aerogels,　efficient　removals　of　MTX　(98.4　%　at　135　min)　and　cationic　dyes　under　various　conditions　were　observed,　in　which　the　adsorption　capacity　reached　28.23　mg/g　for　low　concentration　of　MTX　at　120　min.　After　four　cycles,　the　aerogel　still　retained　93　%　of　its　original　capacity　and　the　removal　rate　was　still　92.4　%.　The　adsorption　process　obeys　second-order　kinetics　and　adheres　to　the　Freundlich　and　Temkin　isotherm　models.　Furthermore,　the　primary　mechanism　by　which　the　aerogels　adsorb　MTX　includes　pore　filling,　electrostatic　interactions,　π-π　conjugation　and　hydrogen　bonding.　The　adsorption　mechanism　was　better　explained　by　the　results　of　density　functional　theory.　Biomass-based　2D/3D　aerogels　are　promising,　low-cost,　eco-friendly　and　highly　efficient　absorbents　for　mitigating　wastewater　contamination.　©　2024　Elsevier　B.V.