Environment-Friendly Preparation of Adsorptive TiO <sub>2</sub>/SiO <sub>2</sub> Core-Shell Nanospheres and V2o5 Microrods from Spent SCR Catalysts by Ultrasonic-Coupled Alkali Leaching Process

Abstract

Spent selective catalytic reduction (SCR) catalysts comprising of valuable V2O5 and TiO2 are usually disposed as hazardous waste because of the toxic V2O5 ingredients. Therefore, recovery of V2O5 and TiO2 from spent SCR catalysts has highly environmental benefits as well as economic value. In this study, an ultrasonic-coupled alkali leaching process was developed for environment-friendly preparation of adsorptive TiO2/SiO2 core-shell nanospheres and V2O5 microrods from spent SCR catalysts. The results show that the synergy of ultrasonic and alkali leaching significantly enhance the separation of V2O5 from spent SCR catalysts, and the addition of NaOH decreases by 70% compared with the traditional roasting-leaching process. The as-prepared adsorptive TiO2/SiO2 core-shell nanospheres exhibit superior adsorptive and photocatalytic performance for 2,4-dinitrophenol removal, and 99.9% of 2,4-dinitrophenol was oxidized within 120 min. In addition, high-purity V2O5 microrods with high H2 S removal rate were efficiently prepared from low-grade filtrate using a hydrothermal precipitation method, which was superior to the traditional NH4VO3 precipitation and solvent extraction process. This study provides a potential method for controlling the environmental pollution of V2O5 and recycling of valuable adsorptive TiO 2 /SiO 2 core-shell nanospheres and V2O5 microrods from spent SCR catalysts.