Study On Ozonation Of Organic Wastewater In A Rotating Bar Reactor

Ozonation has been widely used in the treatment of organic wastewater.However,the ozone solubility in traditional chemical equipment is low and the ozone absorption effect is poor,which resulted in certain limitations at the application of ozonation in the treatment of industrial wastewater.In this paper,a novel rotating bar reactor（RBR）with fixed outer cylinder and rotating inner cylinder was developed to the experiment of treat organic wastewater.Firstly,ozone-water mass transfer experimental system was used to investigate the influences of different variables on mass transfer performance under four inner structures of the main section in the RBR.Then,the sieve plates with different opening sizes in the main section was obtained and one sieve plate with different opening sizes,and combinations of three sieve plates with different opening sizes were added to the gas inlet section.An optimal internal structure was obtained by referring to the experimental results.On this basis,the effects of different variables on decolorization rate（η）,first order apparent decolorization rate constant k(s^-1)and half-life t_1/2（min）of reactive black 5（RB5）wastewater of ozonation were investigated.Then,the influence onηwas studied with the number of cycles as the variable.Finally,the intermediates and final degradation products of RB5 ozonation were analyzed by LC-MS.The main research results of this paper are as follows:1.The ozone-water volume mass transfer coefficient（k _La）of the RBR remains fixedness with the change of C_O3（G）,increment with the increase of Q_G,Q_L,N and V,and decreases with the increase of liquid p H.2.The main section to mean add five spoiler columns and sieve plates with different opening sizes and the gas inlet section to add three sieve plates with different opening sizes are excellent for the mass transfer performance.As such,an optimized inner structure BSS-F_L-F_G is obtained.3.The decolorization rate of RB5 varies with the increase of C_O3（G）, Q_Gand Q_L increases,with the increase of N and the solid holdup of synthetic zeolite tend to be the same after increases,and with the increment of C_RB5,0decreases.Compared with other methods in the literatures of ozone dose,the RBR can achieve the sameηby using less ozone dose,i.e.the efficiency of this experiment is higher.The optimal experimental conditions Q_G:Q_L=100:20 L/h,C_O3（G）=42 mg/L were obtained by one-way experiment.By analyzing the degradation products of RB5,it is shown that the RBR coupled with O₃ has excellent degradation performance and could oxide the large RB5into small molecules.