Nanoarchitectonics preparation of NiO and α-Fe2O3 immobilized on ZSM-5 zeolite for adsorption and photodegradation of rhodamine B from aqueous media

Abstract

NiO and α-Fe₂O₃ were prepared and incorporated onto the as-synthesized ZSM5 zeolite. The resulting powder was used as a photocatalyst in the elimination of the rhodamine B pollutant from aqueous solution under ultraviolet radiation at 252 nm. NiO and α-Fe₂O₃ have porous structures in face-centered cubic and rhombohedral phases, respectively. A band gap of 2.3 and 3.7 eV was reported for α-Fe₂O₃ and NiO, respectively. By acid and charge titration, the point of zero electric charge was calculated to be 11.9, 8.36 and 11.7 for ZSM5, α-Fe₂O₃ and NiO, respectively. The effect of three parameters: pH, rhodamine B concentration, and mass ratio of metal oxide to zeolite was investigated by experimental design with the response surface method. The removal of rhodamine B from the aqueous solution has been done with the help of two phenomena, adsorption on a zeolite and photocatalytic oxidation in the presence of metal oxide. NiO-ZSM5 had a better performance for rhodamine B removal, with an efficiency of 90.48% compared to α-Fe₂O₃-ZSM5 with 69.13% efficiency. Increasing the concentration of rhodamine B had a negligible effect on its removal percentage for both photocatalysts.