Herein, we have reported a graphene and multiwalled carbon nanotubes based nanohybrid as an adsorbent for effective and rapid removal of arsenite and arsenate from real water samples. The nanohybrid was prepared by a combination of Eu-doped magnetic graphene oxide and gold nanoparticle functionalized multiwalled carbon nanotube (Eu-MGO/Au@MWCNT). Herein, the dual behavior (i.e. as adsorbent materials and as electro-active sensing materials) of nanohybrid was explored. The resulting nanohybrid shows desirable magnetic property (15000.0 emu g(-1)) with excellent adsorption capacity for As (III) and As (V) i.e. 320.0 mg g(-1) and 298.0 mg g(-1), respectively. The proposed nanohybrid also shows very good photocatalytic behavior for oxidation of As (III) to As (V), which can be used as an effective tool for conversion of highly toxic for of arsenic to less toxic one. Additionally, the nanohybrid-modified electrode was applied to detect arsenate and arsenite by cyclic voltammetry and square wave voltammetry technique. The linear concentration range for determination of As (III) and As (V) was found from 0.99 to 100.0 mu g L-1 and 2.0 to 85.0 mu g L-1 with LOD 0.27 and 0.99 mu g L-1, respectively. The proposed nanohybrid modified electrode was also applied for the determination of arsenic in various water samples collected from differentially populated/industrial areas. (C) 2016 Elsevier B.V. All rights reserved.