Comparison of catalytic ozonation of phenol by activated carbon and manganese-supported activated carbon prepared from brewing yeast

摘要

Activated carbon (AC) was prepared using brewing yeast as precursor by chemical activation and manganese was supported on activated carbon (Mn/AC) by adsorption-activation method. The characterizations of prepared AC and Mn/AC and their performance as ozonation catalysts was tested. The results indicated that the crystalline phase of supported manganese was MnO. The total BET surface areas of prepared AC and Mn/AC were found to be 1603.0 m~2/g and 598.9 m~2/g, with total pore volumes of 1.43 and 0.49 cm~3/g, respectively. The average pore diameters of AC and Mn/AC were found to be 3.5 ran and 3.3 nm. Adsorption capacities of phenol onto the produced AC and Mn/AC were determined by batch test, at 25℃ and pH 7. Langmuir and Freundlich isotherm models were used to fit the isotherm experimental data, and the Langmuir isotherm model fitted these two adsorption systems well. The maximum uptakes of phenol by AC and Mn/AC were estimated to be 513.5 mg/g and 128.2 mg/g. The presence of AC prepared from brewing yeast was advantageous for TOC reduction of phenol solution compared with single ozonation, and the greatest TOC removal efficiency was obtained in the presence of Mn/AC. All ozonation reactions followed the pseudo-first-order kinetics model well, the degradation rate of phenol was enhanced in the presence of catalysts, and the more pronounced degradation rate was achieved in O_3/Mn/AC system. The rate constants were determined to be 2.16×10~(-2) min~(-1) for O_3 alone, 5.70×10~(-2) min~(-1) for O_3/AC and 6.82×10~(-2) min~(-1) for O_3/Mn/AC.