Effect of low Fe3+ doping on characteristics, sonocatalytic activity and reusability of TiO2 nanotubes catalysts for removal of Rhodamine B from water

► Preparation of Fe-TiO2 nanotubes using sol-gel and hydrothermal methods. ► Activity in the oxidation of Rhodamine B in water under ultrasonic irradiation. ► Band gap energies, surface areas and active surface oxygen vacancies. ► Fe-doped TiO2 nanotubes can be reused for up to 4 cycles. ► Fe:Ti of 0.005 showed the highest sonocatalytic activity.