Activation of sulfite by ferric ion for the degradation of 2,4,6-tribromophenol with the addition of sulfite in batches

In this work, the removal of 2,4,6-tribromophenol (TBP) by ferric ion-activated sulfite [Fe(III)/S(IV)] process was systematically investigated with determining the intermediate products and evaluating the influences of some operational conditions and water matrices. Our results show that batching addition of S(IV) benefits the S(IV) utilization efficiency and TBP removal, with SO4•‒ being the primary reactive radical accounting for TBA degradation. The maximum TBP removal in the Fe(III)/S(IV) process was observed at pH 4.0 and oxygen is essential in this process. With increasing Fe(III) and S(IV) dosages from 0.05 and 0.1 mmol/L to 0.2 and 2.0 mmol/L, respectively, TBP removal followed trends of first increase then decrease. As the acute toxicity of the TBP solution was significantly reduced, the Fe(III)/S(IV) process was believed to be a good choice in the treatment of TBP. Graphical Abstract The combined process of ferric ion and sulfite [S(IV)] has been firstly applied to degrade 2,4,6-tribromophenol with dosing S(IV) in batches, in which sulfate radical plays the dominant role with transforming the most bromine contained in the 2,4,6-tribromophenol into bromide. [Display omitted] .