Preparation Of Hydrophilic Ceramic Composite Membrane And Its Separation Performance Research

With the continuous development of social economy, the human life is also gradually increasing. The phenomenon of water pollution caused by industrial production and human activity is much more serious. And oily wastewater is an important pollution source of the fresh water. Membrane separation technology with low energy consumption, the characteristics of sewage treatment with high efficiency, covers an area of small, were used as the optimization technology to solve the problem of the current water pollution. But, whatever the type of separation membrane should face the problem of membrane fouling. This topic prepares to make organic-inorganic composite membrane with organic materials and inorganic materials. So the composite membrane not only has good chemical stability and high thermal stability, but also holds strong hydrophilicity and mechanical strength. It can help to reduce the effects of membrane fouling and prolong the using time of membrane.In this paper, PVDF and PEG are used to make casting solution. Inorganic ceramic membrane treated with Si O2 sol and silane coupling agent is used as the carrier. The composite membrane is characterized by the infrared absorption spectra, thermogravimetry analysis, scanning electron microscope(SEM), surface contact angle tester. The influence of coating method, concentration of PVDF and PEG, the heating treatment temperature on the properties of composite membrane were studied. The result shows that the hydroxyl groups are successfully introduced on the composite membrane surface and the thermal stability of the composite membrane is improved too. The membrane was completely decomposed at about 509℃.The best optimal performance of ceramic composite membrane is prepared by the method of roller coating under the condition of 50℃.The concentration of casting solution is 6wt.%PVDF-6wt.%PEG. The pure water permeate flux reaches 2119.6 L/(m2·h) under 0.1MPa.In the process of oily wastewater treatment, the influence of preparation process of membrane, the oil concentration of the feed liquid, operating pressure and the filtration time on the performance of oily wastewater separation were studied. The result shows that the best optimal performance of ceramic composite membrane is prepared by the method of roller coating under the condition of 50℃.The concentration of casting solution is 6wt.%PVDF-9wt.%PEG. When filtered 200 mg/L of oily wastewater, the composite membrane flux maintained at 32 L/(m2·h) after 300 min under the pressure of 0.2MPa. The oil concentration of filtrate was 4.2 mg/L detected by ultraviolet spectrophotometry and the maximum rejection values have been observed to vary from 92.3% to 97.9%.When filtered the e. coli solution, the sterilization rate of composite membrane was 99.9998%. The membrane surface morphology was observed under the SEM and the membrane pore size is about 25 nm.