It　is　crucial　for　water　environment　security　to　remove　its　p-arsanilic　acid　(p-ASA)　efficiently.　Namely,　removing　p-arsanilic　acid　from　aqueous　media　through　magnetic　separation,　has　become　a　novel　method　of　removing　toxic　pollutants　from　water.　Batch　adsorption　experiments　demonstrated　a　higher　adsorption　of　lignin-based　magnetic　activated　carbon　(201.64　mg　g−1)　toward　p-ASA.　In　addition,　LMAC　nanoparticles　exhibited　typical　magnetism　(35.63　emu　g−1　of　saturation　magnetization)　and　could　be　easily　separated　from　the　aqueous　solution.　Meanwhile,　the　endothermic　adsorption　of　p-ASA　over　LMAC　could　spontaneously　proceed　and　be　well　described　by　the　pseudo-first-order　and　pseudo-second-order　model　as　well　as　the　intra-particle　diffusion　model.　Moreover,　the　mechanisms　during　p-ASA　adsorption　over　LMAC　included　the　electrostatic　attraction,　surface　complexation,　π-π　stacking　and　hydrogen　bonding　interaction.　Importantly,　lignin-based　magnetic　activated　carbon　has　high　absorbability　and　preferable　reusability　in　real　water　samples.　Consequently,　this　paper　provides　insights　into　preparation　of　the　lignin-based　magnetic　activated　carbon　may　be　potential　adsorbents　for　the　remediation　of　organoarsenic　compounds.　©　2020　Elsevier　Ltd