| Due to the characteristics of highly concentrated, high toxicity and high resistance to microorganisms, chemical pharmaceutical wastewater became one of the most important sources of pollutants in water environment. Advanced oxidation processes have been proposed to dispose such kind of wastewater. As one of the important branches of AOPs, ozonation and catalytic ozonation have received extensive concerning. In this paper, 1H-Benzotriazole and guaiacol have been choosed as the target contaminant to investigate the processes of ozonation and catalytic ozonation, respectively. The effect parameters, such as ozone dosage, initial target contaminant concentration and initial p H value were studied with focus on the target contaminant degradation and the COD removal. And the degradation mechanisms and degradation pathways have been investigated. Meanwhile a kinetic model was established to evaluate the effect of ozone dosage, initial 1H-Benzotriazole concentration and initial p H value in the ozonation process. The catalytic performance of the three self-made magnetic catalysts was evaluated in the catalytic processes and the construction and composition of the catalysts have been characterized by several technologies.Firstly,1H-Benzotriazole has been choosed as the target contaminant, we investigated the abatement of highly concentrated 1H-Benzotriazole in aqueous solution by ozonation focusing on the COD removal and 1H-Benzotriazole degradation at different initial 1H-Benzotriazole concentrations(100-1000 mg/L), ozone dosages(16-48 mg/min) and initial p H values(3-11). It was found that the degradation of 1H-Benzotriazole was obviously affected by the initial concentration of 1H-Benzotriazole, p H value and O3 dosage and the optimized p H value was observed at 11. Under the same conditions, the increasing of ozone dosage and the p H value would accelerate the degradation efficiency of BTA and CODcr removal, while the increasing of initial 1H-Benzotriazole concentration would hamper this process. A kinetic model C=C0exp(-70.401QO32.4997C0-2.1262[OH-]0.0444t) was established to evaluate the effect of ozone dosage, initial 1H-Benzotriazole concentration and initial p H value on the degradation of 1H-Benzotriazole. The catalytic performance of the three self-made magnetic catalysts was evaluated in the process of catalytic ozonation of 1H-Benzotriazole. It was found that the catalytic activity of Fe3O4@Si O2@Yb2O3 was the most excellent one among the three synthetic catalysts. The effect parameters, such as catalytic materials, catalysts dosages and the effect of catalysts to the decomposition of ozonation have been investigated in the catalytic ozonation process. It was found that the increase catalysts dosage can accelerate the 1H-Benzotriazole degradation and the catalyst Fe3O4@Si O2@Yb2O3 can accelerate the ozone decomposition.Then, the construction and composition of the catalysts Fe3O4@Si O2@Yb2O3 have been characterized by XRD, SEM, EDX and FT-IR. It was found that the self-made catalysts Fe3O4@Si O2@Yb2O3 was magnetic and have the core-shell structure.Finally, Guaiacol has been choosed as the target contaminant, the degradation of high concentration guaiacol in aqueous solution by ozonation and catalytic ozonation processes were studied. The effect parameters, such as ozone dosage(16-40 mg/min), initial guaiacol concentration(0.1-1.0 m L/L) and initial p H value(3-11), on the ozonation process were studied with focus on the guaiacol degradation and the COD removal. A representative rare earth metal catalysts Fe3O4@Si O2@Yb2O3 were prepared and the catalytic performance were evaluated at the condition of different catalysts dosage(0-2.0 g) and different initial p H value(3-11). The results showed that the increasing of ozone dosage and the decreasing of initial guaiacol concentration at the same condition was avail to the ozonation process. The catalytic performance of the catalysts was performed well at the condition of 1.0g catalysts dosage and initial p H of 9.0. A pathway of degradation of guaiacol has been proposed based on the intermediate by-products we have detected by GC/MS and IC in this process. |
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