Study On The Preparation And Separation Performance Of Plate Type Ceramic Membrane

In this dissertation,the plate type ceramic membrane and it’s application wasprepared and applied in tanning wastewater. First of all, with the study of a greatdeal of literatures, the research progress of ceramic membrane and classificationfeature were reviewed and the application of ceramic membrane in wastewatertreatment was introduced, the research objective and significance of thisdissertation were presented.In the research preparation process of plate type ceramic membrane, usingthe traditional ceramics preparation procedure at first, the main material wasderived from aluminum oxide, added appropriate pore-forming agent andsintered additives, and the body was prepared with squeeze shaped method. Afterdrying, the supports was sintered according to certain firing system. In theexperimental process, the TG/DSC curves of raw materials powder wereanalyzed by using PC/PG thermoanalytical instrument. The effects of supports’sintering temperature on the shrinkage were studied. The effects of different thesintering temperature, holding time and materials powder particle size on porestructure and size of supports were studied. The effect of the pore former dosageon porosity was studied. The results show that sintering temperature1200℃,holding time6h, porous agent more than20%, it can be prepared the uniformpore size distribution, porosity, and accorded with more than50%of porousceramics water demand separation membrane supports.And then, on the ceramic membrane support which has prepared, ceramicmembrane transition layer are prepared by the same method. In the preparationprocess of transition layers, the influence of the four factors such as the quantityaddition of Al2O3, PVA and nanometer ZnO, and pH value of material liquid onpore size, poriness, filtrate flux and the degree of binding from transition layerswith supports were explored by using orthogonal experiment method. In the research, the crystal phase structure of transition layers were analysed anddiscussed in different sintering temperature by XRD, and it determined thatsintering temperature of transition layers was1200℃. At the result, the optimalscheme of each factor was determined, and ceramic membrane transition layer ofmeeting the requirements was prepared.After determining preparation plan and the firing technology of transitionlayer, the ceramic membrane with uniform distribution of pore size was preparedby sol-gel with aluminum isopropanol as the main raw material. And the collosolwas obtained by hydrolysis and alcoholysis reaction, then gelatinize and heattreatment. In the research, the TG/DSC and XRD of ceramic membrane gel wereanalyzed, the crystalline state structure of ceramic membrane was deeplyanalyzed. In the sol-gel preparation process, the effects of hydrolysis temperature,aging temperature, roasting temperature and pH value, PVA content on ceramicmembrane were studied. The results show that hydrolysis temperature was85℃,aging temperature was90℃, roasting temperaturewas between500℃and600℃, pH valuewas3, dosage of PVA was between15%and25%, the ceramicmembrane of surface morphology rules, uniform pore size distribution, suitableporosity and meet the requirements was prepared.Finally, the ceramic membrane with pore size of0.2μm,3μm and10μmwere chosed, and used to treat tanning process wastewater. The hardness, sulfidecontent, ammonia nitrogen and COD before and after the wastewater treatmentwere analyzed, calculate and compare their removal rates. Results indicated thattanning process wastewater was treat by plate-type ceramic membrane, theremoval rate of wastewater hardness was over63%, the removal rate of sulfide,COD and NH3-N could be achieved83%. The removal efficiencies were perfect,and were up to the national discharge standard, also can be recycled in industrywastewater treatment. In addition, the pollution mechanism of plate type ceramicmembrane are analyzed, and presented several kinds of clean method in morecommon use at present. In the cleaning process, it should be paid attention to thechoice of the cleaning fluid and the control of the cleaning conditions.