科研之友
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摘要
The present study employed a Mn-Cu/Al2O3 heterogeneous catalytic ozonation process for tertiary treatment of actual tannery wastewater, focusing on its feasibility in that application. The primary factors affecting the removal efficiency of organic pollutants were investigated, including catalyst dosage, ozone dosage, and initial pH value. The experimental results showed that the addition of a Mn-Cu/Al2O3 catalyst improved the removal efficiency of chemical oxygen demand (COD) during ozonation, which initiated a 29.3% increase for COD removal, compared to ozonation alone after 60min. The optimum pH, catalyst dosage, and ozone dosage were determined to be 7.0, 2.0g/L, and 0.3g/h, respectively. Under these conditions, following 60min of reaction, the COD removal efficiency and the concentration in effluent were 88%, and 17mg/L, respectively. In addition, the presence of tert-butanol (a well known hydroxyl radical scavenger) strongly inhibited COD removal via Mn-Cu/Al2O3 catalytic ozonation, indicating that the Mn-Cu/Al2O3 catalytic ozonation process follows a hydroxyl radical (OH) reaction mechanism. The Mn-Cu/Al2O3 catalyst exhibited good stability and reusability. Finally, the kinetic analysis revealed that the apparent reaction rate constant of COD removal with the Mn-Cu/Al2O3 catalytic ozonation system (0.0328min(-1)) was 2.3times that of an ozonation system alone (0.0141min(-1)). These results demonstrated that the catalytic ozonation using Mn-Cu/Al2O3 is an effective and promising process for tertiary treatment of tannery effluent in biological systems.
