Simultaneous oxidation of phenol and bisphenol A by permanganate: Synergetic or competitive effect

• When phenol and BPA coexist, permanganate oxidation exhibits different behavior.
• Phenol and BPA have a synergetic effect on their oxidation at pH 4.0–6.0.
• BPA has a competitive effect on the phenol oxidation at pH 7.5–8.5.
• Manganese oxide is responsible for the synergetic effect.
• Reactive manganese intermediates is responsible for the competitive effect.

When permanganate is used for oxidizing organic micropollutants in water, multiple organic micropollutants may exist at the same time, and the oxidation behavior may be different from the case of oxidation of individual organic micropollutant. Phenol and bisphenol A (BPA) were chosen to evaluate the simultaneous oxidation of organic micropollutants by permanganate over the pH range of 4.0–8.5. Different initial concentrations of BPA and ways of initiating the reaction were employed to distinguish the reactive species, and second-order kinetics was used to confirm it. The results show a synergetic effect under weakly acidic conditions (pH from 4.0 to 6.0) that the existence of phenol and BPA improves the removal by permanganate each other. The improvement of phenol removal increases with the initial concentration of BPA and decreases with increasing pH. However, it exhibits a competitive effect under weakly alkaline conditions (pH from 7.5 to 8.5) that phenol removal is inhibited in the presence of BPA, and BPA removal is slightly improved when phenol coexists. The inhibition of phenol removal is greater at pH 8.5 than at pH 7.5. It is proposed that the generation of manganese oxide induced by BPA is responsible for the synergetic effect and the reactive manganese intermediates, Mn(V) or Mn(VI), may be responsible for the competitive effect.

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