Novel KMnO4-modified iron oxide for effective arsenite removal

► We employ the MnBT-4 adsorbent for As (III)/(V) removal in solution. ► The waste iron oxide BT-4 acts as the support to immobilize Mn using FBR reactor. ► MnBT-4 has higher arsenite adsorption as compared with BT4. ► Easy solid-liquid separation and cost effective are the merits of applying MnBT-4.