Optimization and mechanism analysis of α-Fe₂O₃ catalytic ozone oxidation parameters for phenolic wastewater

The traditional process has a limited effect on the treatment of phenolic wastewater, and catalytic ozonation technology can effectively treat phenolic wastewater. α-Fe₂O₃ has exhibited high ozone catalytic activity in previous experiments. ·OH produced by catalysis can non-selectively mineralize phenol and intermediate products, which significantly enhances the removal of pollutants and the level of ozone utilization. In order to clarify the main influencing factors of the catalytic ozone oxidation process and optimize the process parameters, phenol was used to simulate phenolic wastewater, and L₁₆(4⁴) orthogonal experiment was designed. The results showed that ozone dosage, catalyst dosage, pH, and reaction time were the main influencing factors of COD removal rate and COD degradation per unit ozone. Among them, ozone dosage and reaction time had the most significant impact on the two indicators. Variance analysis and experimental verification showed that catalyst dosage had little effect on COD removal rate, and reaction pH had little effect on COD degradation per unit ozone. The optimized process parameters were calculated by weight matrix: ozone dosage was 5 mg/(L·min), catalyst dosage was 0.1 g/L, pH was 9, and reaction time was 45 min. Tert butyl alcohol shielding experiments showed that ·OH significantly promoted the catalytic ozone oxidation process.