Heterogeneous Catalytic Ozone Oxidation For Pharmaceutical Wastewater Treatment

Ozonation process is a novel alternative to advanced Oxidation Technologies in the area of the technology of water treatment. The systems of single ozonation, ozone/activated carbon and ozone/modified activated carbon were studied in this paper. p-toluene sulfonic acid (p-TSA) and high concentrated organic wastewater was selected as pollutants, three operation parameters (pH, initial concentration of pollutants, the dosage of ozone, the dosage of activated carbon) was studied in this paper, dynamics model of single ozonation system and dynamics model of the system ozone/activated carbon were established, the reaction mechanism of the degradation of p-TSA and high concentrated organic wastewater were studied. moreover, BOD5/CODCr of high concentrated organic wastewater was enhanced to provide basic data and theoretical basis and reference for industrial applications.p-toluene sulfonic acid (p-TSA), a typical intermediate in pharmaceutical wastewater, was selected as model pollutant for the study of ozonation technology. The results showed that at the conditions of pH 2^-13, ozone flow rate 6-64 mg·min^-1and pollutant concentration 100-5000 mg·L^-1, the degradation were followed the pseudo-first-order kinetics. The high pH, ozone flow rate and low concentration were enhanced the reaction constants. The reaction kinetics model of ozonation was set up to describe the contribution of direct reaction and indirect reaction. 3kHO2·/k0.was select as kinetics parameter for the study of direct oxidation and indirect oxidation. The effects of pH, ozone flow rate and pollutant concentration on 3k_HO2·/k₀.were carefully analyzed, which would be helpful for the application of ozonation in pharmaceutical wastewater pollution control.Integration of ozone and activated carbon was applied to treated a kind of typical pharmaceutical Intermediates: p-toluenesulfonic acid (p-TSA). The integrated degradation process of ozone and activated carbon was studied. The results revealed that the integrated process enhanced the removal efficiency of p-TSA and COD, the synergy effect was significantly displayed in the integrated process. The results also indicated that pH, ozone flow rate, activated carbon concentration have a obvious effects on COD removal efficiency, high pH, high ozone flow rate and high activated carbon concentration can enhanced the COD removal. The fitting of kinetic model with the experiments results proved the truth of the synergy effect of the integrated process. Furthermore, there were some difference in reaction mechanism when the activated carbon was added or not, through the analysis of FTIR, SEM, BET, the surface feature of activated carbon were characterized, and the results also supported the accelerated characterization mentioned above.Heterogeneous catalytic ozone oxidation was applied as an efficient way of pretreatment for highly concentrated pharmaceutical wastewater. The pretreatment of real pharmaceutical wastewater in the system of individual ozonation and ozone/activated carbon were studied, Compared with the individual ozonation and activated carbon adsorption, the results showed that the integrated process could greatly improve the removal efficiency of COD with an obviously syngestic effect. It was found that in the integrated process, COD removal could reach 72.6% on the condition of pH 12 quantity of activated carbon 20 g·L^-1 and quantity of ozone 64 mg·min^-1 with the effect of TOC removal 57.7%, BOD₅/COD 0.345, achieving the biodegradation of pharmaceutical wastewater. pH has obvious influence on the removal of COD, the increase of pH has obvious inhibition on adsorption of active carbon, compared with acid condition, high removing rate could be gained in alkaline condition. The dosage of ozone and activated carbon also have marked effect on COD removal, the increase of their dosage could obviously enhance the removal efficiency of COD. Lumped kinetics model could be well applied on the pharmaceutical wastewater treatment. Through the analysis of pHpzc SEM, BET and infrared spectrum, there were some differences in reaction mechanism at different pH conditions, this point could be proved through the fitting analysis of kinetic model, at the acid condition, the major function of activated carbon was adsorption, while in basic condition, the major function was catalyzed ozonation.A novel functional activated carbon was gained when palladium and lanthanum were loaded on activated carbon, and catalysis characterization was discussed in this paper. the dosage of noble metal, calcined temperature, approach of preparation of activated carbon and so on, and the optimal parameter was gained. Also, as the model pollutant, p-toluene sulfonic acid (p-TSA) was degraded in this study. By the method of modern instruments, the mechanism of the degradation of pollutants in the system of ozone/activated carbon was analysed.