Acid digestion of radioactive combustible wastes. Use of hydrogen peroxide for acid digestion of ion exchange resins.

Dissolution and mineralization of ion exchange resins: differentiation between heterogeneous and homogeneous (photo-)Fenton processes

“…These radicals are reacting along three reaction channels: 21 hydrogen abstraction, electrophilic addition to p-systems and electron transfer. In the case of the IER used in this work (sulfonated and 1,4-divinyl-benzene cross-linked polystyrene), hydrogen abstraction would mainly concern the tertiary C-centers of the polystyrene backbone (reaction (11)), (11) whereas electrophilic addition to p-systems would occur on the aromatic moieties of the polymer substrate (reaction (12)). (12) In the present work, oxidative degradation of IER suspended in aqueous solutions and mineralization of the dissolved fragments by the Fenton and photo-Fenton processes were investigated in detail.…”

“…Alternatively, different processes were proposed and investigated for the disposal of used IER, e.g. incineration, 7 thermal decomposition, 8-10 acid "digestion" 11 as well as wet oxidation. 12 Only few results are known concerning a controlled (partial) oxidation of polystyrene-based IER by hydrogen peroxide (H 2 O 2 ) and catalyzed by transition metal ions (Fenton or Fenton-type processes 13 ).…”