Investigation on the detailed mechanisms of cationic ion exchange resin gasification in supercritical water by ReaxFF reactive molecular dynamics simulation

Supercritical water gasification technology holds significant promise for the treatment of radioactive exchange resin generated by nuclear power plants. This study examines the detailed mechanisms of cationic ion exchange resin (CIER) gasification in supercritical water using ReaxFF reactive molecular dynamics simulations. The evolutionary behavior of the CIER molecular structure in supercritical water has been elucidated. The ring-opening reaction of aromatic intermediates is identified as the key reaction influencing gasification. By increasing the hydroxyl group on the benzene ring structure, the ring-opening dissociation energy of the aromatic ring is reduced from 163.11 to 81.65 kcal mol⁻¹. Furthermore, the sulfonic acid group is progressively diminished by hydrogen radicals, ultimately converting into H₂S. The formation pathways of gaseous products (H₂, CO, CH₄, and CO₂) were thoroughly explored. These findings provide theoretical guidance for the exploration of optimized methods for CIER gasification in supercritical water.