Bromate ion removal by electrochemical reduction using an activated carbon felt electrode.
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 electrochemicaltreatment of BrO3- -contaminated tap water resulted in a rapid decrease in BrO3- concentration from 100 to 48 microg/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.
Faculty of Science and Technology, Ryukoku University, Otsu 520-2194, Japan. naoyuki@rins.ryukoku.ac.jp
Naoyuki
N
Kishimoto
Nobuaki
N
Matsuda
D001959:Bromates / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
D001959:Bromates; D014874:Water Pollutants, Chemical; D002244:Carbon