Regeneration of Arsenic- and Barium-Poisoned V2O5–WO3/TiO2 SCR Catalyst

Regeneration of catalysts through arsenic and alkaline rare earth removal can not only solve the environmental problems caused by the stacking of deactivated catalysts and arsenic pollution, but also reduce the economic investment required to produce new catalysts. After analyzing the structure and composition of the spent V2O5–WO3/TiO2 catalysts obtained from a power factory, their existence, form and content were determined for As and Ba. NaClO was used as both an oxidant and a base source in leaching As. It first oxidizes the highly toxic and adsorbed stable As(III) into the more water-soluble As(V). Meanwhile, the OH− produced by hydrolysis provides an alkaline environment, promoting the conversion of As5+ to soluble AsO43− and facilitating the desorption and dissolution of As from the catalyst. Taking into account the removal rate of arsenic and the loss of active ingredients, the optimal process conditions were determined. The BaSO4 was removed using the EDTA complexation method and the optimal conditions were determined. The elution and regeneration process not only removed arsenic but also effectively unblocked the pore structure of the catalyst. The redox capacity of the regenerated catalyst was significantly enhanced, and the number and strength of acid sites and the denitrification performance were also effectively restored.