文摘
The electrochemical removal of bromate ion (BrO3−) was investigated using a two-compartment electrolytic flow cell with activated carbon felt electrodes. Bromate ion removal and corresponding Br− increase was observed during electrochemical treatment, whereas the activated carbon felt used possessed no catalytic effect on BrO3− reduction. The BrO3− reduction rate was accelerated at lower pH, which also improved current efficiency. Transition of chemical equilibrium of the BrO3− reductive reaction was theorized as the reason for pH dependency of the BrO3− reduction. The electrochemical treatment of BrO3−-contaminated tap water resulted in a rapid decrease in BrO3− concentration from 100 to 48 μg/L with a contact time of 9.2 s. Thus, electrochemical treatment allowed the rapid removal of BrO3−. However, competitive hydrogen evolution at the cathodes reduced current efficiency of BrO3− reduction. Standard potentials of corresponding anodic and cathodic reactions suggested that electrolysis at a terminal voltage less than 1.229 V would promote BrO3− reduction without hydrogen evolution. However, the activated carbon felt electrode did not function well at a terminal voltage of 1.0 V. Accordingly, the development of an electrode material with high catalytic activity will be required to improve current efficiency.