The influence of thermal aging on catalytic activity, weight loss, phase structure, surface area and pore characteristic of commercial V2O5-WO3-TiO2 selective catalytic reduction (SCR) catalyst were investigated using a fixed bed reactor, TG-DTA, XRD and nitrogen adsorption. The catalyst showed good catalytic activity and thermal stability in fresh state or aging for 50 h at 550 °C and 650 °C in air. The catalyst drastically deactivation after calcination for 50 h at 650 °C in air, the maximum conversion of NO dramatically decreased from 100 to 60 %, the light off temperature increased from 187 to 360 °C. The analysis revealed that the deactivation of catalyst was caused by three factors. Firstly, the reduction of vanadia loading was caused by the vocalization; secondly, the reduction of the active site was resulted from the interaction V2O5 with TiO2 and lastly, the changes of reaction area and pore structure were due to the phase transformation of TiO2 from anatase to rutile.

Spiramycin (SPM), a widely employed antibiotic in both clinical therapy and the livestock industry, poses significant challenges in terms of safe and efficacious management. A heterogeneous photo-Fenton system, devised using Schwertmannite (Sch), can effectively degrade contaminants. However, it is accompanied by a relatively low conversion efficiency of ≡Fe3+/≡Fe2+ and a significant iron loss. In this study, a catalyst featuring Fe3O4 and ZSM-5 molecular sieve-modified Sch (Fe3O4/ZSM-5/Sch) was devised to enhance the catalytic activity and stability. The findings revealed that Fe3O4/ZSM-5/Sch exhibited exceptional catalytic activity, with the reaction first-order kinetic exceeding that of pure Sch. The active species including ·OH, h+, e−, ·O2− and SO4·− were identified in the UV/Fe3O4/ZSM-5/Sch-H2O2 system. The enhanced catalytic activity of Fe3O4/ZSM-5/Sch could be ascribed to the effective conversion of ≡Fe3+/≡Fe2+. The photogenerated electrons within Fe3O4 were transported to Sch via ZSM-5, which effectually reduced ≡Fe3+/≡Fe2. Moreover, Fe3O4/ZSM-5/Sch demonstrated outstanding stability; even after six cycles, the degradation efficiency of SPM remained above 86.50%, and the leaching quantity of Fe remained below 0.24 mg/L. This research not only develops an excellent catalyst for the safe treatment of SPM but also proffers innovative perspectives for the future design of efficient iron-based catalysts.