Raising the pH and temperature of spent chlorination (C) stage liquor caused a substantial removal of organically bound halogen. Chlorophenols, chloroguaiacols, chlorovanillins, and chloroacetic acids were rather stable in both alkali extraction (E) and C-stage liquor in the pH range 2-12, even at higher temperatures (100°C). The concentration of chlorocatechols decreased at pH > 8, whereas the concentration of chloroguaiacols increased. In C-stage liquor the concentration of chlorovanillins increased at pH > 4. Treatment with UV light in combination with hydrogen peroxide caused a rapid removal of AOX (adsorbable organic halogen) and of chlorophenolic compounds in both C- and E-stage liquor, but it had no effect on chloroacetic acids or chloroacetones. © 1994.
Smeds, A., Holmbom, B., & Pettersson, C. (1994). Chemical stability of chlorinated components in pulp bleaching liquors. Chemosphere, 28(5), 881–895. https://doi.org/10.1016/0045-6535(94)90005-1