Catalytic effects of V 2 O 5 on oxidative pyrolysis of spent cation exchange resin

Pyrolysis is a cost-effective and safe method for the disposal of radioactive spent resins. In this work, the catalytic effects of V 2 O 5 on the pyrolysis of cation exchange resin are investigated for the first time. The results show that it is a better catalyst than others so far studied and achieves a lowering of final pyrolysis temperature and residual rate simultaneously when aided by physical blending. The maximum reductions of the final pyrolysis temperature and the residual rate are 173 °C and 11.9% (in weight), respectively. Under the action of V 2 O 5 , low-temperature (445 °C) removal of partial sulfonic acid groups occurs and the pyrolysis of the resin copolymer matrix is promoted. This is demonstrated by the analysis of pyrolysis residues at different temperatures by X-ray photoelectron spectroscopy (XPS) and element analysis. The catalytic activity of V 2 O 5 is determined by effects both at acid sites and oxidation-reduction centers via H 2 -TPR (temperature programmed reduction), O 2 -TPD (temperature programmed desorption), CO 2 -TPD, and NH 3 -TPD. The catalytic effect of oxidation-reduction centers in V 2 O 5 is achieved by close contact with the sulfur bond through chemisorption under the effect of acid sites. V 2 O 5 is also believed to be the reason for the removal of partial sulfonic acid groups at lower temperatures (445 °C). V 2 O 5 is an effective catalyst for spent resin pyrolysis and can be further applied in industry.