⎫ The adsorption capacity of arsenic on the prepared novel iron oxide nanoparticles was 1.96 mg/g having higher surface area with excellent catalytic degradation property. ⎫ The adsorption dataset best fits in the Langmuir model (pseudo-second-order model). ⎫ To check the removal efficiency of arsenic by iron oxide magnetite nano catalyst (adsorbent) on real water samples was 81.09% and synthetic water prepared on laboratory was 99.8% tested by Inductively couple plasma mass spectrometry (ICP-MS) instrument.