PSF Ultrafiltration Membrane Surface Modification And A Modified Membrane–Flocculation Process Study On The Treatment Of Micro-polluted Source Water Of Ganjiang River

In this day and age, with the development of economy and the acceleration ofindustrialization, water pollution turns to be a serious issue which attracted muchconcern. Meanwhile, people prefer to choose potable water with high quality tosatisfy the demand of daily life while our life has reached a high level, recently.However, the traditional water purification technology is difficult to meet theserequirements either in efficiency or deepness of processing. Membrane treatmenttechnology has been widely used in the solution to water problems due to its lowenergy consumption, high efficiency, non-disinfection products which can be used atroom temperature. In this paper, we did some researches on the surface modificationof ultrafiltration membrane. To obtain the best effect of the modification, wecoordinated the PSF ultrafiltration membrane with polyaniline and titanium dioxide,combined the modified membrane with coagulation process to deal with the slightlypolluted water problem in Gan River, the effect of practical application was alsoinvestigated.We synthesized polyaniline using the dispersion copolymerization method, whihseparated the process of adsorption and oxidation polymerization of aniline. Firstly,adsorbed the aniline monomer uniform on the membrane surface, the diaphragm waspolymerized in antioxidant to avoid the big loss of membrane flux when monomercontinuously adhered on the membrane surface resulting in such a dense compositelayer during the polymerization of aniline. We laid hydrophilic TiO2particles on thepolyaniline composite layer, and modified the polysulfone membrane with bothorganic and inorganic materials. Four influencing factors were chosen, that is TiO2dosing quantity, concentration of SDBS, pH value and the APS dosing quantity. L9(34) orthogonal test was designed, and best effect of the modification was obtainedwith the comprehensive balance analysis:0.40g/L TiO2,5g/L SDBS, pH=2.0,0.80g/L APS. Compared to the pristine polysulfone membrane, the modified PSF has acontact angle reduced from65.23°to50.21°, the holding rate increased from53.20%to53.20%, the flux decline rate reduced from75.32%to44.51%, the pure water flux recovery rate increased from40.37%to40.37%, and the pure water flux reducedfrom594.47L/m2to501.35L/m2. The pure water flux is slightly reduced, which isresult from the transmission resistance caused by the addition of polyanilinecomposite layer. However, the membrane hydrophilic, entrapment rate and pollutionresistance indexes have greatly ascend.The electron microscope scanning indicates that the bore structure on the crosssection of the polysulfone membrane did not change obviously, and modified layerwas mainly concentrated on the surface of the original film. Compared with othermodification of PVDF membrane in our group, the performance of compositemembrane which is synthesized by the dispersed in-situ polymerization method wasmainly decided by polyaniline composite layer on the surface of the base film, andwas insensitive the basal membrane pore structure and the initial performance.The coagu—flocculation process to deal with the slightly polluted water problemin Gan River determined the optimum combination process of PAC dosage was30mg/L~40mg/L.In the addition, modification of ultrafiltration and the original filmon turbidity removal rate was more than99%;in the removal efficiency of UV254andammonia nitrogenremoval efficiency of about20%, the modified membrane than theoriginal film about time limit; ultrafiltrationmembrane two times in the original basic...