Study On Wettability Of Filter Media By Using Osmotic Pressure Method & Its Influence On Filtration Results Of Oily Water

Oily wastewater is generated by various industries, such as petroleum extraction, oil processing, petroleum transportation, mechanical workout, electromechanical machining and petrochemical industry. This kind of trade waste has an enormous quantity and widely range and it is a great harm to the water environment. Filtration is a typical tertiary treatment method for oil-bearing water, suitable for oil particulates smaller than 10μm and the lower oil concentration. This method is normally used as a unit operation combined with other methods. The kinds of filter media and its surface nature have an important influence on treatment result in the filtration unit operation. The wettability of filter media is the most important influence factor.Study on the wettability of filter media, and to show its chemical determinant by analyzing the filter media's surface chemical construction from a deep degree. Meanwhile, we combine the wettability with oily wastewater treatment result and find out their relationship. These works will be good helps for choosing suitable filter media, as well as provide theoretical base and evaluation methodology for modifying filter media and creating new filter media.The lipophilic and hydrophilic properties of anthracite, activated zeolite, bauxite ceramic, magnetite and zeolite were studied by using dynamic osmotic Pressure method, which is based on the principle of Washburn Equation. To show the main cause of the discrepancy for different filter media, by analyzing the surface chemical construction using XPS and FTIR. Experiment on three staple kinds of filter media using dynamic filtration oil removal test, we got the relationship between wettability and oily wastewater treatment result, the three kind of filter media are anthracite, magnetite and zeolite. Through these experiments mainly got the following conclusions:1. When filter media size distribution are 20-30 meshes and 30-40 meshes respectively, using dynamic osmotic pressure method to study wettability of the filter media is feasible and the experiment results is precise and credible.2. When the particle size distribution are between 20meshes and 30 meshes, the LHR values of anthracite, activated zeolite, bauxite ceramic, magnetite and zeolite are 2.51,1.77,1.75,1.32 and 1.26 respectively, when the particle size distribution are between 30meshes and 40 meshes, the LHR values of activated zeolite, bauxite ceramic and magnetite are 2.28,2.27 and 0.86 respectively.3. XPS and FTIR results show that the surface of above five filter media all contains absorbed water. The surface of anthracite is composed of organic compound; the surface of activated zeolite mainly contain SiO₂silicate, Al₂O₃ and Fe₂O₃; the surface of bauxite ceramic is composed of SiO₂ and Al₂O₃;the surface of magnetite is mainly composed of SiO₂,silicate and Fe₃O₄; the surface of zeolite is composed of SiO₂, silicate and a little Fe₂O₃.4. The order of polarity magnitude is zeolite > magnetite > activated zeolite, bauxite ceramic > anthracite. Therefore, the LHR values are increscent gradually. This is in accord with the surface analysis results.5. For the 15mg/Limitation oil wastewater, anthracite's filtration oil removal result is better than magnetite's, and magnetite's filtration oil removal result is better than zeolite's. The average removal rate for the former 5 hours of anthracite, magnetite and zeolite are 86.93%,75.92%,68.57% respectively, the average oil concentration of yielding water for the former 5 hours are1.90mg/L,3.62mg/L,4.65mg/L respectively.6. The filtration oil removal rates of anthracite, magnetite and zeolite are increscent gradually with the increasing of their LHR value. Therefore, using LHR value to evaluate the wettability of filter media is feasible, the bigger of LHR value the more lipophilic, and the filtration oil removal result is better.