Efficient degradation of methylene blue dye by catalytic oxidation using the Na_8Nb_6O_9·13H_2O/H_2O_2 system

摘要

Na_8Nb_6O_9·13H_2O/H_2O_2-13H_2O particles were synthesized by a simple hydrothermal method. The catalysts were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and thermogravimetric and differential scanning (TG-DSC). The XRD and TG-DSC analyses indicated that Na_8Nb_6O_9·13H_2O/H_2O_2 was an intermediate hexanio-bate during the preparation of NaNbO_3 powders. Methylene blue (MB) dye degradation using Na_8Nb_6O_9·13H_2O/H_2O_2, Nb_2O_5/H_2O_2 and NaNbO_3/H_2O_2 systems were investigated, respectively. Among the catalytic oxidation systems, Na_8Nb_6O_9·13H_2O/H_2O_2 showed the highest activity for degradation of MB in the presence of H2O2. The results indicated that the dye degradation efficiency could be 93.5% at 30 °C after 60 min in the presence of the Na_8Nb_6O_9·13H_2O/H_2O_2 system. It was also found that the degradation of MB over the catalytic systems followed pseudo-first-order kinetics, and the degradation rate was 0.02376 min~-1 in the Na_8Nb_6O_9·13H_2O/H_2O_2 system, which was higher than that in the Nb_2O_5/H_2O_2 and NaNbO_3/H_2O_2 systems. A possible mechanism for MB catalytic oxidation degradation using the Na_8Nb_6O_9·13H_2O/H_2O_2 system was proposed.