Given　their　considerable　solubility　in　water　and　potentially　high　toxicity　to　human　health,　organoarsenic　compounds　have　become　an　emerging　contaminant.　Herein,　a　heterogeneous　Fenton　process　mediated　by　SiO2-coated　nano　zero-valent　iron　(SiO2-nZVI)　was　employed　to　simultaneously　remove　the　p-arsanilic　acid　(p-ASA,　a　typical　organoarsenic　compound)　and　the　released　arsenic.　The　initial　pH　value　significantly　influenced　on　the　degradation　of　p-ASA　and　at　the　optimal　pH　(3.0),　p-ASA　(10 mg L−1)　could　be　completely　oxidized　to　As(V),　NH4　+,　and　plentiful　phenolic　compounds　such　as　phenol　and　p-hydroquinone　via　the　cleavage　of　C–N　and　C–As　bonds　within　60 min　in　pure　water.　Meanwhile,　although　the　formed　lepidocrocite　and　magnetite　on　the　surface　of　SiO2-nZVI　significantly　limited　the　reutilization,　they　played　a　vital　role　in　the　adsorption　of　the　released　As(V)　and　the　residual　arsenic　levels　in　the　effluent　were　as　low　as　0.031 mg L−1,　meeting　both　the　drinking　water　standard　of　the　World　Health　Organization　(WHO)　and　the　surface　water　standard　of　China　(0.05 mg L−1).　Furthermore,　high-level　dissolved　organic　matters　(DOM)　(>　2 mg　C　L−1)　exhibited　strong　interference　with　both　the　oxidation　of　p-ASA　and　adsorption　of　arsenic,　but　the　interference　could　be　eliminated　by　increasing　the　SiO2-nZVI　dosage　or　adding　H2O2.　Importantly,　this　system　could　completely　remediate　p-ASA　in　a　short　time　and　simultaneously　avoid　the　secondary　pollution　caused　by　inorganic　arsenic,　which　was　significant　for　the　remediation　of　organoarsenic　pollutants　in　swine　wastewater.　©　2020,　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.