Recycling strategies of spent V2O5-WO3/TiO2 catalyst: A review

The demand for V2O5-WO3/TiO2 catalysts is growing as many countries impose increasingly stricter limits on nitrogen oxide emissions. Unfortunately, after service, the spent V2O5-WO3/TiO2 catalyst is continuously and considerably discarded. The cost of the catalyst accounts for approximately 30-50% of the total investment in the denitration system. Additionally, the spent catalyst contains significant amounts of valuable metals and some heavy metals. Thus, the regeneration to form a new catalyst or recovery of valuable metals from the spent V2O5WO3/TiO2 catalyst has gained widespread attention in recent years, not only for meeting the growing demand for corresponding critical metals/catalysts but also reducing the potential ecological and environmental hazards caused by inappropriate disposal. In this article, a systematic review of the literature was conducted to examine recently developed processes and technologies for recycling the spent V2O5-WO3/TiO2 catalyst to recover either new catalysts or valuable metals. Moreover, the challenges associated with process optimization for the regeneration to form a new catalyst and the recovery of valuable metals were analyzed. The aim of this article is to provide a guideline on how effective processes and techniques for the spent V2O5-WO3/TiO2 catalyst recycling can be developed and to motivate further studies in this theme for industrial-scale realization.