Efficient　and　rapid　removal　of　p-arsanilic　acid　(p-ASA)　in　water　is　very　important　in　environmental　protection　and　human　health,　however　it　is　still　a　severe　challenge　in　actual　engineering.　Herein,　a　novel　sorbent　(CF-PEI)　was　successfully　fabricated　by　simply　modifying　the　amphiphilic　skin　collagen　fiber　(CF)　substrate　with　Polyethylenimine　(PEI).　The　as-prepared　CF-PEI　exhibits　high-efficiency　adsorption　for　negatively　charged　p-ASA　with　aromatic　rings　due　to　the　introduction　of　amino　groups　and　the　existence　of　hydrophobic　bands,　and　the　maximum　adsorption　capacity　of　CF-PEI　for　p-ASA　was　high　up　to　285.71　mg　g−1.　In　addition,　the　adsorption　mechanism　of　CF-PEI　on　p-ASA　mainly　includes　electrostatic　interaction,　hydrogen　bond　and　amphiphilicity.　The　multi-level　all-fiber　structure　of　CF　makes　it　mainly　focus　on　surface　mass　transfer　with　short　mass　transfer　distance,　and　its　capillary　drainage　effect　can　realize　large　flow　and　rapid　separation.　CF-PEI　based　on　CF　can　realize　the　ability　to　separate　low-concentration　p-ASA　with　high　flow　rate　and　high　efficiency.　The　effective　processing　volume　was　12.5　L　g−1　when　the　separation　flux　reached　as　high　as　9931.27　L　m−2　h−1.　Notably,　the　p-ASA　adsorbed　on　CF-PEI　was　almost　completely　eluted　by　NaOH　(0.5　mol　L−1).　The　adsorbent　is　convenient　to　prepare,　recyclable,　high　in　efficiency,　and　has　a　great　application　prospect　in　removing　organic　micro-pollutants.　©　2021　Elsevier　Ltd