Effect of the kind of cupric compound deposit on thermal decomposition of anion exchangers

摘要

The effect of the inorganic deposit on the thermal decomposition of hybrid ion exchangers (HIXs) has not been comprehensively studied before. Therefore, as part of this research anion exchangers containing cupric compound in their matrix (CuO, Cu(OH)(2) and Cm-4(OH)(6)SO4) were subjected to thermal analysis. Strongly basic commercial anion exchangers, i.e. a macroreticular anion exchanger (M) and a gel-like anion exchanger (G), were used as the host materials. M, M/CuO, M/Cu(OH)(2) and G, G/CuO, G/Cm-4(OH)(6)SO4 were subjected to thermal analysis under respectively air and N-2. The samples of the HIXs contained 57.8-84.5 mg Cu/g. The results of twelve experiments are discussed on the basis of the TG/DTG curves and XRD patterns for the solid residues. The effects of: (a) the process conditions, (b) the type of deposit and (c) the structure of the anion exchanger on the course of the thermal transformations, the process end temperature, the amount of carbonizate in the post-pyrolysis residue and the composition of the inorganic phase (CuO after combustion, Cu-0 or Cu2S after pyrolysis) were determined. It was demonstrated that during the thermal decomposition of the HIXs under N-2 the reduction of Cu(II) was taking place, and owing to this hydrogen-consuming conversion more carbonizate formed than in the pyrolysis of the pure resins, as under hydrogen deficit the hydrocarbon radicals condensed into large non-volatile particles.