Influences of inorganic anions on oxidation of phenol by CuO-H₂O₂

Phenol was selected as a model pollution substrate. The influences and mechanism of inorganic anions on its oxidation were investigated in neutral solution at low temperature and atmospheric pressure. Results showed that phenol could be removed efficiently by CuO and H₂O₂ with 94.7% removal rate in 10 min, which followed hydroxyl radical oxidation mechanism. Inorganic anions influenced the oxidation with different mechanisms. Higher concentration would lead to more significant influences. HCO₃^-1 accelerated the inefficient decomposing of H₂O₂. The decomposing rate constants increased from 0.3738 min^-1 at concentration of 0 mmol · L^-1 to 0.5347 min^-1 at concentration of 20 mmol · L^-1. The TOC removal rate constants decreased from 0.267 min-1 to 0.0194 min^-1 correspondingly. HPO₄^2- retarded the H₂O₂ decomposing and inhibited the phenol oxidation. The decomposing rate constants of H₂O₂ and the removal rate constants of TOC decreased from 0.3738 min^-1, 0.267 min^-1 to 0.0338 min^-1, 0.0338 min^-1 respectively. Cl^- was good at H₂O₂ decomposing and phenol removal with simultaneously increasing the H₂O₂ decomposing rate constants and the TOC removal rate constants from 0.3738 min^-1, 0.267 min^-1 to 0.6040 min^-1, 0.3879 min^-1 respectively. NO₃^- and SO₄^2- had few influences on H₂O₂ decomposing and phenol removal.