Preparation And Properties Of Ceramic Membranes Modified By Metal Carbon Based Materials

Membrane separation technology,as a sustainable green process,is widely used in industrial wastewater treatment and water resource utilization.Membranes are mainly divided into polymer membranes and inorganic ceramic membranes.Compared to polymer membranes,inorganic ceramic membranes have high porosity,high thermal and mechanical stability,and high hydrophilicity;It has unique advantages in terms of anti bacterial pollution performance and separation performance.However,in the application process of membrane,membrane fouling,especially the decline in membrane flux and service life caused by biological pollution,has become the main factor limiting its further development.Therefore,it is of great significance to study cost-effective methods to improve membrane fouling resistance,delay the reduction of membrane flux,and extend the service life of the membrane.In this paper,copper oxide and activated carbon powder were used to modify ceramic membranes,and the effects of modification conditions on membrane properties were studied.The stability and anti pollution ability of the modified membranes were also studied.Further explore the cleaning effects of different membrane cleaning methods on modified membrane fouling.The main research and conclusions carried out in this article are as follows:The modified sol gel impregnation calcination method was used to prepare the ceramic membrane（M-CuO）loaded with copper oxide nanoparticles.The experimental results show that the distribution of nano copper oxide on the surface of the modified film becomes more uniform as the number of impregnations increases.Nanometer copper oxide modification can lead to a slight decrease in the pure water flux of the modified membrane.Compared to the original membrane,the pure water flux of the modified membrane decreases by 12.7%,15.5%,and 18.7%when the immersion times are 1,2,3,respectively.Activated carbon micropowder modified membrane（M_C）and activated carbon micropowder/nano copper oxide modified ceramic membrane（M-CuO_C）were prepared by suction filtration deposition method.The experimental results showed that activated carbon micropowder deposition resulted in a slight decrease in the pure water flux of the membrane（12%）.After the preparation of the modified film,the surface characteristics of the film before and after modification were analyzed using scanning electron microscopy（SEM EDS）,X-ray diffraction,Fourier transform infrared spectroscopy,contact angle tester,Zeta potential,and other characterization methods.The results showed that after modification,CuO nanoparticles and activated carbon micropowders were well loaded on the surface of the ceramic membrane.CuO nanoparticles can significantly enhance the hydrophilicity of the modified membrane,but activated carbon ultrafine powder can reduce the hydrophilicity of the ceramic membrane.Compared to the original ceramic membrane,the hydrophilicity of the modified M-CuO_Cbasically remains unchanged.The stability experiment of the modified film further shows that the CuO nanoparticles are stably loaded and are not easy to overflow from the surface of the modified film,but the deposition of activated carbon fine powder is not stable enough,which will lead to an increase in TDS.However,the overall TDS value is small,and the load of the modified material is basically stable.Static bacteriostasis and dynamic actual operation were used to test the antifouling performance of the modified ceramic membrane.The loading of CuO effectively improved the antibacterial performance of the ceramic membrane.In the actual operation of MBR,the TMP of the modified ceramic membrane increased slowly compared to the original ceramic membrane,indicating that it has good biological pollution resistance performance.At the same time,the removal effects of COD,NH₄⁺-N,and TP were investigated,and it was found that the modification of ceramic membranes would not affect the removal of pollutants or even improve their removal efficiency to a certain extent.In addition,the normal growth of sludge in MBR,and the impact of ceramic membrane on sludge amount is smallThe analysis of different resistance models for modified ceramic membranes shows that the modified ceramic membranes loaded with activated carbon and CuO nanoparticles are mainly characterized by filter cake layer resistance（R_g）and membrane pore resistance（R_i）,respectively.At the same time,due to the effect of the modified material itself,the overall resistance is relatively high,and the actual operation effect of the ceramic membrane is less affected.The physical cleaning,HCl cleaning,and NaOH cleaning effects of modified ceramic membranes were investigated.By observing the pure water flux after cleaning,it was found that the modified ceramic membrane had excellent membrane flux recovery rate.It was found that the modified ceramic membrane loaded with CuO had slower pollution compared to M0and MC at the initial stage of operation,and the rate of re pollution after cleaning was faster.However,the physical cleaning and HCl cleaning of the modified ceramic membrane loaded with activated carbon powder had a smaller decrease in TMP compared to the unloaded one.Overall,the modified ceramic membrane had better membrane cleaning effectThe contaminated activated carbon on the surfaces of M_C and M-CuO_C will be damaged to a certain extent after cleaning.Therefore,it is necessary to reload the activated carbon powder and observe the changes in the pure water flux of the ceramic membrane during secondary use.It is found that reloading the activated carbon on the modified ceramic membrane does not significantly reduce the pure water flux of the ceramic membrane.