Experiment Research Of Photo Catalytic-membrane Separation Coupling Process On Simulated Dyeing Wastewater Treatment

Printing and dyeing wastewater is the primary sources of pollutants in the textileprinting and dyeing industry whose composition is complex, and has highconcentrations of pollutants. Moreover, the discharge of sewage is large. Thedecolorization and mineralization is a big challenge in dealing with the printing anddyeing wastewater, especially. In recent years, the treatment of printing and dyeingwastewater is become more and more difficult, due to the development of the textileindustry, accompanied with the improving of emission standards in the environmentalprotection requirements. As a result, more and more researchers and enterprise focuson the advanced treatment technology of the printing and dyeing wastewater.On the basis of the preliminary study results, In this paper, directing at theproblem of advanced treatment of dyeing and printing wastewater, in order toimprove the catalyst activity of catalyst and the membrane flux, and also to reducemembrane fouling and work out the damnify of PVDF membrane material oxidatedby O₃and UV-light, a research is operated respectively about the catalyst modified,membrane properties and reactor design. In the last, an integrated photo catalysis -membrane separation reactor is designed and explored in dealing with the simulatedreactive brilliant red X-3B wastewater. According to the experimental results, the besttreating conditions is studied.In catalyst modification, a method of valid combination of adsorption ofactivated carbon and photo catalytic of TiO₂by aera loading on the activated carbonpower in the way of Sol Gel method is presented in the paper. In the experimentalstudies, the optimal load conditions are as follows: the calcinations temperature is500℃, the calcinations time is four hours, continuous load three times. After an hourtreatment of 50 mg/L reactive brilliant red X-3B wastewater, the decolorization rate reached 99.9%, and the mineralization rate was over 80% by adding 1g/l catalyticagent prepared on above, which is stimulate by 125W high pressure mercury lamp.The conclusions of characterization by SEM, XRD and IR show that mass TiO2wereloaded on activated carbon, and the supported catalysts particle size became largerand the structural characteristics of TiO2 is anatase.In the experiment of membrane module performance test, the average pore sizeof less than 0.1μm PVDF flat ultrafiltration membrane is used to resolve the problemof membrane flux instability and easy blocking of hollow fiber used before. Theresults show that PVDF flat ultrafiltration membrane can not only intercept thecatalyst, but also obtain a higher membrane flux （100LMH） under low transmembranepressure （5kpa）, and can also keep the lowest membrane fouling level. In thisexperiment, it is an important improvement of using flat membrane instead of hollowfiber to achieve the advanced treatment of printing and dyeing wastewater.In this paper, during the designing and structuring of reactor, in order to ensurelong-time running of the membrane module and continuous and steady operation ofthe integrated photo catalysis-membrane separation reactor, firstly, membraneresistance study is carried out to demonstrate the resistance of the membrane materialby UV radiation and anti-ozone oxidation; secondly, according to the response bandof titania catalyst and the spectral properties of microwave electrodeless UV lampused in this experiment, the extinction characteristics of UVA and UVB, in the dyesolution, the catalyst suspension, the dye and catalyst mixture are studied, which aregenerated by simulated light source and whose main wavelength are 365nm and254nm respectively. The result shows that, in this experimental condition, thepropagation distance of UVA and UVB is only 3-5cm; ultraviolet light can be wellabsorbed by dye and catalyst solution. Finally, an integrated photocatalysis-membrane separation reactor is designed and maken out, according to theresults of membrane resistance and ultraviolet extinction experiments.According to the results above, an integrated photo catalysis-membraneseparation reactor is well designed, which is used in the advanced treatment ofsimulated reactive brilliant red X-3B wastewater. Through some comparativeexperiments, the optimum condition is using four electrodeless lamp, and the ratio ofgas and water is 50:1, and the initial dye concentration is 50mg / l, and catalyst dosageis 1g/l. Under this condition, after six hours continuous treatment, the dyedecolorization and mineralization rates are respectively 80% and 30%.