Bromate removal in water through electrochemical reduction using Magnéli phase titanium oxide electrode†

Abstract

This study demonstrates the effective electrochemical degradation of bromate, achieving over 95% removal, using both sheet electrodes and reactive membranes fabricated from Magnéli phase titanium oxide (Ti_nO_2n−1, n = 4–10). Increasing the applied voltage and electrolyte concentration, as well as decreasing the pH, significantly enhanced bromate reduction efficiency. Experimental results suggest that both direct and indirect pathways contribute to the overall degradation process. The impact of coexisting ions was also evaluated. At 1 mM, their inhibitory effect was negligible, whereas, at 10 mM, the inhibition became pronounced in the order SO₄²⁻ > CO₃²⁻ > Cl⁻ ≈ NO₃⁻ ≈ NO₂⁻ > ClO₄⁻. When applied to secondary effluent wastewater, this electrochemical approach achieved 70% degradation of bromate within six hours. Moreover, the Magnéli phase titanium oxide electrodes exhibited excellent stability and reusability, highlighting their potential for real-world water and wastewater treatment applications.