Treatment Of Amoxicillin Wastewater With Rotating Packed Bed By O₃/Fenton Process

In recent years, the production and application of antibiotics have made great development worldwild, at the same time posed a serious threat to ecosystem. Most of antibiotics wastewaters are unsuitable for treatment by conventional wastewater treatment processes. The advanced oxidation processes, which can produce the strongest oxidant known in wasterwater treatment-hydroxyl radicals, have been widely used in wastewater treatment field due to its high oxidizability and no secondary pollution. However, the low utilization rate of usual oxidant such as ozone and Fenton as well as the low solubility of ozone limit the application of advanced oxidation processes. In this study, the high-gravity intensification technology (rotating packed bed, RPB) was used to intensify the mass transfer and mixing efficiency in AOP process to explore the degradation effect of amoxillin wastewater in Fenton process,03+Fenton process, Fenton+O3process and O3/Fenton process. This study has reached the following conclusions:1、Experimental results show that the influence of parameters to the four processes are essentially the same. With the increase of the initial Fe(II) concentration, temperature, rotating speed and initial pH the COD removal rate increased at the start and then decreased after the degradation effciency of amoxicillin reaching peaks at the optimum reaction parameters. The COD removal rate decreased with the increase of the liquid flow rate.2、It is found that the COD removal rate and biodegradability of amoxillin wastewater after treated by step-by-step-oxidation method (O3+Fenton process and Fenton+O3process) and coupling oxidation (O3/Fenton process) have a significant increasing, and have obvious advantages than Fenton process.3、O3/Fenton process simplified the procedure of step-by-step oxidation. The COD removal rate of amoxicillin in the O3/Fenton process reached57%with a temperature of25℃, rotating speed of800/min, pH of3, Fe concentration of0.4mM, gas flow rate of2.5L/h, and liquid flow rate of30L/h, and BOD5/COD increased significantly from0to0.38, indicating that the as-treated wastewater is suitable for a subsequent biochemical treatment.4、The intermediates during amoxicillin ozonation were detected by Quattro Premier XE and the probable degradation pathway of amoxicillin aqueous solution was proposed. It can be concluded that the degradation pathway of amoxicillin in step-by-step-oxidation method (O3+Fenton process) and coupling oxidation (O3/Fenton process) are essentially the same. S7(2-(4-hydroxyphenyl)-2-nitroacetic acid) was difficult to befurther oxidized by Fenton process, Fenton’s oxidability concerns insufficient. On account of part of large molecules have not been fractured in O3+Fenton process, O3/Fenton process has the strongest oxidizing in the three processes.