Study On The Treatment Of High-concentrated Rhodamine B Wastewater By Catalytic Wet Oxidation Based On Microchannel Reactor

Strengthening the treatment of water pollution is related to a country’s industrial development and environmental protection and the high concentration organic wastewater has always been an important topic in environmental pollution.The catalytic wet oxidation（CWO）technology is a kind of advanced oxidation process（AOPs）,which is a common and effective method in the treatment of high-concentration organic wastewater.In this paper,the CWO technology was used to study high concentration organic wastewater with oxygen.In order to improve the oxidation performance of the CWO technology,the high concentration Rhodamine B simulated wastewater and actual industrial wastewater of the ultraviolet absorber BP-2 were degraded by the CWO process in a novel microchannel reactor in this study.The main research conclusions are as follows:The Rhodamine B simulated wastewater with an initial COD（Chemical Oxygen Demand,unit:mg/L）concentration of 30000 mg/L was degraded by a microchannel reactor combined with the CWO process and the COD removal rate was92.4%.The effects of various process conditions on the COD removal rate of Rhodamine B were studied and the optimum process conditions of the degradation were found:Catalyst system(20 mg/L Cu²⁺+0.5 g/L PMS),Q_total=60 m L/min,P=50 bar,T=240℃,Q_G:G_L=6:1.During the degradation of Rhodamine B by the CWO process in microchannel reactor,the catalytic activities of the different metal salts were studied.The result showed that the copper salt exhibited the best catalytic performance and peroxymonosulfate（PMS）could effectively promote the generation of free radicals as a strong oxidant combined with copper salt,which was a highly effective oxidation promoter.The process of homogeneous wet oxidation of Rhodamine B was described based on the well-known"generalized kinetics"model of homogeneous wet catalytic oxidation.The catalytic wet oxidation kinetics of Rhodamine B was studied in the temperature range of 210～230℃.The degradation kinetic equations of Rhodamine B at different temperatures were fitted and the degradation rate constant,the degradation order and degradation activation energy of Rhodamine B were obtained.The degradation mechanism and pathway of Rhodamine B were preliminarily speculated by the analysis of the degradation intermediate products of Rhodamine B by high-performance liquid chromatography（HPLC）.The actual industrial wastewater of the UV absorber BP-2 was degraded by the CWO process in microchannel reactor.The result showed that the COD concentration of the raw wastewater decreased from 210265 mg/L to 23358 mg/L and the removal rate reached 88.9%.When the BP-2 wastewater was diluted twice and degraded,the COD concentration of the wastewater was reduced to 9142 mg/L and the removal rate was 91.3%,which met the requirement of pretreatment of high concentration wastewater in industry.