Fe(III) modified Egeria najas driven-biochar for highly improved reduction and adsorption performance of Cr(VI)

Abstract A novel Egeria najas driven-biochar was activated by loading ferric chloride onto surface (FeCl3@EN-BC). The synthesized composite was evaluated for its physicochemical properties and Cr(VI) adsorption behavior and mechanism. The result of SEM showed that the modified biochar is less porous than raw Egeria najas biochar, but loaded with γ-Fe2O3 and Fe3O4 crystals. In addition, the results of FTIR, XRD and XPS also confirmed that Fe was successfully loaded on the Egeria najas biochar. Cr(VI) was efficiently removed by FeCl3@EN-BC within the pH range from 2.5–8.5. The thermodynamics parameters suggested that the adsorption processes of Cr(VI) were all spontaneous and endothermic. The overall removal mechanism was regarded as adsorption, surface complex formation, reduction and ion exchange reaction. Therefore, this modified biochar derived from Egeria najas has a potential of practical application in the removal of Cr(VI) from wastewater.