Abstract: Pyrolysis is a cost-effective and safe method for the disposal of radioactive spent resins. In this work, the catalytic effects of V₂O₅ 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 V₂O₅, 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 V₂O₅ is determined by effects both at acid sites and oxidation-reduction centers via H₂-TPR (temperature programmed reduction), O₂-TPD (temperature programmed desorption), CO₂-TPD, and NH₃-TPD. The catalytic effect of oxidation-reduction centers in V₂O₅ is achieved by close contact with the sulfur bond through chemisorption under the effect of acid sites. V₂O₅ is also believed to be the reason for the removal of partial sulfonic acid groups at lower temperatures (445 °C). V₂O₅ is an effective catalyst for spent resin pyrolysis and can be further applied in industry.

Key words: Waste disposal; Cation exchange resin; V₂O₅; Catalysis; Oxidative pyrolysis

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