Enhanced photocatalytic activity of Fe3O4-WO3-APTES for azo dye removal from aqueous solutions in the presence of visible irradiation

摘要

Development of highly active photocatalysts for treatment of dye-laden wastewaters is vital.The photocatalytic removal of azo dye Reactive Black 5 was investigated by Fe3O4-WO3-3-aminopropyl-triethoxysilane(APTES) nanoparticles in the presence of visible light.The Fe3O4-WO3-APTES nanoparticles were synthesized via a facile coprecipitation method.The photocatalyst was characterized by XRD,FT-IR,SEM,EDX,VSM,UV-Vis,and pH_(PZC) techniques.The effects of some operational parameters such as solution pH,nanophotocatalyst dosage,initial RB5 concentration,H2O2 concentration,different purging gases,and type of organic compounds on the removal efficiency were studied by the Fe3O4-WO3-APTES nanoparticles as a photocatalyst.Maximum phtocatalytic activity was obtained at pH 3.The photocatalytic removal of RB5 increased with increasing H2O2 concentration up to 5 mM.The removal efficiency declined in the presence of different purging gases and all types of organic compounds.First-order rate constant(k_(obs)) decreased from 0.027 to 0.0022 min~(-1) and electrical energy per order(E_(EO)) increased from 21.33 to 261.82(kWh/m~3) with increasing RB5 concentration from 10 to 100mg/L,respectively.The efficiency of LED/Fe3O4-WO3-APTES process for RB5 removal was approximately 89.9%,which was more effective than the LED/Fe3O4-WO3 process(60.72%).Also,photocatalytic activity decreased after five successive cycles.