Study On Anti-fouling Performance Of Catalytic Ceramic Membrane Modified By Mixed Metal Oxides

Ultrafiltration membrane separation technology has a broad application prospect,but membrane fouling is the main reason to restrict its application.In this paper,the ceramic ultrafiltration membrane fouling and anti-fouling properties of catalytic ceramic membrane modified by mixed metal oxides were studied.In order to study the fouling properties of ceramic ultrafiltration membrane,the ultrafiltration membrane fouling process was analyzed by the ultrafiltration of HA,SA,BSA and their mixture NOM feed liquid,and the influence of ozone coupling on NOM membrane fouling was investigated separately.BSA membrane fouling is the most serious,and only 2.5% of it is reversible fouling,which may be due to the fact that the particles in the BSA feed liquid are more likely to enter the membrane pore and deposit on the membrane pore wall through adsorption.NOM and SA membrane fouling are also relatively serious and similar,and the proportion of reversible membrane fouling is about 25%.The fitting effect of the two kinds of feed liquid for each membrane fouling model is basically the same.The degree of HA membrane fouling is the smallest,and the proportion of reversible membrane fouling is the highest at 47.5%.The fouling mechanism of overlapping membrane pore blocking and filter cake layer supplemented by non-overlapping membrane pore blocking may be the reason for the low degree and good reversibility of HA membrane fouling.The ozone coupling reduced the NOM feed liquid membrane specific flux reduction rate by 26.6%,and increased the recovery rate of flux by 38.7%,indicating that ozone coupling can reduce the degree of membrane fouling and increase the proportion of reversible membrane fouling.Ozone coupling increases the contribution of non-overlapping membrane pore blocking to the decrease of membrane flux,which may be the reason for the increase of membrane fouling reversibility.Ozone oxidation can increase the electronegativity and hydrophilicity of organic membrane pollutants and oxidize large organic molecules into small ones,which may be the main reasons that degree of membrane fouling is reduced.In order to stabilize the composition of the modified mixed metal oxides,the modified calcination temperature should be at the stage of no significant change at the high temperature of each thermogravimetric sample,i.e.750?.XRD,FTIR,XPS,SEM characterization and catalytic performance of cobalt-manganese and copper-manganese mixed metal oxides were analyzed in order to improve the catalytic properties in the ozone coupling process and the anti-fouling performance of the modified catalytic ceramic membrane.In the XPS analysis of mixed metal oxides,Mn₂CoO_x have the highest proportion of surface adsorbed oxygen,surface hydroxyl and adsorbed H₂ O molecules.Mn₂CoO_x has better catalytic performance from the perspective of microstructure.In the SEM analysis,the microstructure of Mn₂CoO_x in copper-manganese sample is obviously different,which may be due to the fact that it meets the conditions for spinel formation.In the analysis of catalytic performance,the removal rate of UV254 shows that the catalytic performance of cobalt-manganese mixed metal oxides is better than that of copper-manganese mixed metal oxides,and the catalytic effect of the former is similar in different proportions,while the catalytic effect of Mn₂CoO_x of the latter is the best.According to the three-dimensional molecular fluorescence,the catalytic oxidation effect of Mn₂CoO_x and Mn Co2 Ox on the fluorescent components of BSA and HA was significantly better than that of Mn Co Ox,and the catalytic oxidation effect of Mn₂CoO_x was the best among the copper-manganese mixed metal oxides.To sum up,Mn₂CoO_x and Mn₂CoO_x have better catalytic performance,and the corresponding modified catalytic ceramic membrane has better catalytic performance in the coupling process of ozone oxidation,which can better reduce the degree and increase the reversibility of membrane fouling.Because the catalytic performance and hydrophilicity of the modified membrane were improved obviously,the anti-fouling property of membrane was improved.The ceramic membrane modification was homogeneous and modified mixed metal oxides had good adhesion and were not easy to fall off.The modified mixed metal oxides particle size could reach nanometer level and size distribution was narrow.The modification has a good effect and it has obvious advantages in the preparation and improvement of anti-fouling performance of modified catalytic ceramic membrane.