As　an　emerging　micropollutant,　p-arsanilic　acid　(p-ASA)　would　release　highly　toxic　arsenate　and　arsenite　during　migration　transformation.　Herein,　a　three-dimensional　polyethylenimine-aminated　leather　collagen　fiber　(CF-PEI)　decorated　with　MgZnFe　(MZF)　metal　oxides,　i.e.,　CF-PEI@MZF　monolith,　was　reported　for　the　ultradeep　p-ASA　removal.　The　synergetic　functions　of　hydrogen　bonding　and　electrostatic　interaction　from　the　CF-PEI　and　coordinative　interaction　from　the　MZF　on　the　monolith　allow　an　ultrarapid　kinetic　that　could　achieve　ca.　80%　of　the　adsorption　equilibrium　within　20　min　and　a　benchmarked　exothermic　Langmuir　adsorption　capacity　as　high　as　588.24　mg　g-1　for　the　p-ASA.　It　also　performed　an　unparalleled　feasibility　in　the　continuous　treatment　to　reduce　the　concentration　of　p-ASA　to　below　0.05　mg　L-1　for　real　applications.　We　also　highlight　the　monolith　structure　with　great　features　of　easy　separation　and　recycling　use　for　real　industrial　applications.　All　these　demonstrate　the　merits　of　our　CF-PEI@MZF　monolith　in　addressing　environmental　engineering　challenges.　©　2024　American　Chemical　Society