Enhanced photo-Fenton degradation performance over multi-metal co-supported SAPO-18 zeolites by promoted active species yield

Abstract

Fe, Mn co-supported SAPO-18 zeolite was synthesized via ion-exchange method and exhibited high performance in catalytic degradation of methyl orange (MO). The bimetallic Fe-Mn/SAPO-18 catalyst showed almost 100% MO (50 mg/L) removal within 20 min, which was superior to the MO degradation efficiency over monometallic Fe or Mn catalysts. The hydroxyl group (OH) generated in the photo-Fenton catalysis was determined by fluorescence probe and the corresponding reaction mechanism was explored. We proposed that the light and synergistic effect of bimetal promote the conversion of metal ion valence, thereby enhancing the generation of the active species and the degradation efficiency of MO. Furthermore, the influences of some essential factors on MO degradation rate were investigated. The results indicated that the pH of the solution plays an important role in Fenton degradation of MO. 100% MO degradation is achieved within 10 min when the initial pH is set at 2–3 under UV for Fe-Mn/SAPO-18. Moreover, it also shows good performance under neutral conditions, thus exhibits considerable activity at expanded pH range. And the concentrations of H2O2 and MO solution and the dosage of catalysts can influence the degradation rate of dyes. This work not only made significant progress on the development of high-performance catalysts for the degradation of MO, but also provided a direction for the study of organic contaminant degradation.