EB-radiolysis of carbamazepine: in pure-water with different ions and in surface water

The electron beam (EB) radiolysis characteristics of carbamazepine (CBZ) in pure-water with different ions and that in surface water were studied in this paper. It suggested that the center dot OH, center dot H and e (aq) (-) all played roles on CBZ EB degradation, and the center dot OH played the vital role. Acidic solution was favorable for CBZ degradation, while alkaline environment inhibited it. HSO4 (-) and SO3 (2-) enhanced the CBZ degradation, but CO3 (2-), NO2 (-), NO3 (-) NH4 (+) and Cl- inhibited. In surface water, the EB-radiolysis was an effective way to degrade CBZ; and CBZ might evolve in three different ways during EB radiation: reduction by e (aq) (-) and center dot H (intermediate 10,11-dihydrocarbamazepine (I)), oxidization by center dot OH (intermediates 10,11-dihydro-10-11-expoxycarbamazepine (II) and 2(3)-hydroxycarbamazepine (III)) and hydration into 10,11-dihydro-10-hydroxycarbamazepine (IV) and finally the intermediates were all mineralized into CO2, H2O, N-2 and NH4 (+). All the results contribute to study the EB-radiolysis of pharmaceuticals in surface water.