The Development Of The Photocatalytic Vacuum Ultraviolet And Ozone Oxidation As An Integrated Reactor

Photocatalytic technology has ob vious advantages compared with conventional treatment technology due to its characteristics of environmental protection,clean,safe,non-toxic,mild reaction conditions,most organic compounds mineralized by energy,and no secondary pollution.Photocatalytic technology is used in combination with other technologies to promote or coordinate the degradation of organic pollutants,which can improve the effect of pollutant degradation in the reactor,such as ozone oxidation.Compared to conventional the combination of photocatalysis and ozone oxidation technology,ozone generator is required to the preparation of ozone,which increase equipment cost and energy consumption.In term of cost,it is not conducive to industrial popularization and application.With the basis of developing the photocatalysis vacuum ultraviolet oxidation reactor,the research of this paper has developed the photocatalytic vacuum ultraviolet and ozone oxidation as an integrated reactor.The reactor can recycle the ozone generated by oxygen in the 185 nm vacuum ultraviolet radiation,and implement the integration of the vacuum ultraviolet oxidation,ozonation and photocalysis.It will synergize the degradation of organic pollutants that greatly improve the efficiency of pollutant degradation and mineralization.The main conclusions of this paper are as follows:（1）At first,a photocatalytic vacuum ultraviolet oxidation reactor is developed.It is determined that the main wavelength of the reactor light source is 185 nm vacuum uv lamp,which the length of the lamp tube is 500 mm,the outer diameter is 15 mm,and the power is70 W.The reaction tube adopts quartz spiral tube with a length of 430 mm,which the inner diameter of the quartz tube is 8mm,the pitch is 12 mm,and the inner diameter of the spiral tube is 20 mm.The photocatalyst adopts V-N-TiO₂/glass bead composite material with a diameter of 5⁶mm,which is filled into the spiral tube.（2）The effects of different light sources,initial concentration,circulating flow rate、p H andHCO₃^-value on the degradation of phenol by vacuum ultraviolet photooxidation has studied in the photocatalytic vacuum ultraviolet oxidation reactor.We concluded that the process of degradation of phenol by vac uum ultraviolet photooxidation is consistent with the first order reaction kinetics.The degradation rate of VUV is the fastest,and the degradation rate constant is 0.022min^-1.The higher the initial concentration,the worse the degradation effect.The optimal circulation flow is 0.2 L/min,and the optimal p H value is 6.HCO₃^-can capture hydroxyl radicals and reduce the degradation rate of phenol significantly.（3）Having studed the effect of vacuum light oxidation,circulating flow,phenol initial concentration,aeration mode,and p H value to mineralize phenol in the photocatalytic vacuum ultraviolet oxidation reactor.The results show that the vacuum photooxidation have certain effect on phenol mineralization,but it is better to mineralize phenol by combining photocatalysis.Phenol mineralization in pure O₂ aeration is the best.When the circulating flow rate is 0.5L/min,and the p H value is 6,phenol mineralization is the best.The overall effect of metal ions and inorganic anions in tap water on photocatalytic vac uum ultraviolet photooxidation phenol is that negative is greater than positive,which is not conducive to mineralization of phenol.（4）Developing the compact structure and simple process of photocatalytic vacuum ultraviolet and ozone oxidation as one of the reactor.The mineralization rate constant of phenol is 3.01 and 2.10 times of single VUV,UV/V-N-TiO₂,and 1.48,2.08 and 2.60 times of VUV/V-N-TiO₂,VUV/O₃ and UV/V-N-TiO₂/O₃.It greatly improves the mineralization of phenol and implents the synergistic effect of the three.（5）The oxidation process of phenol has studied in this reactor.The degradation rate constant of phenol is 0.02236min^-1,and the rate constant of phenol mineralization is 0.01091min^-1,which is 2.05 times that of the latter.It is concluded that the degradation of phenol is faster and easier than total oxidation of CO₂ and H₂O.When the process of actual phenol wastewater,the mineralization performance should be more accurate and practical as an indicator.（6）Orthogonal experimental study is carried out on the reactor of the photocatalytic vacuum ultraviolet and ozone oxidation.The effects of initial concentration,pH,circulating flow and air volume on the performance of phenol mineralization is investigated.It is concluded that the initial concentration of phenol has the greatest influence on the mineralization performance.The lower the concentration,the better the mineralization.The optimal combination is that when the initial concentration of phenol is 10mg/L,the circulation flow is 0.5L/min,the p H is 4,and the air input is 0.2L/min,and the 4h mineralization rate is92.6%.（7）The economic analysis of the the photocatalytic vacuum ultraviolet and ozone oxidation as an integrated reactor is carried out.When the treatment of simulated phenol wastewater is 0.05L/h,the cost of the equipment is 2856.00 yuan,and the water treatment cost is 0.164 yuan/L.