Font Size: a A A

Treatment And Recovery Of Phenol From Coal-chemical Industry Wastewater Using SiO2/PDMS/PVDF Composite Pervaporation Membranes

Posted on:2017-04-09Degree:MasterType:Thesis
Country:ChinaCandidate:D Y LiFull Text:PDF
GTID:2271330509456829Subject:Environmental Science and Engineering
Abstract/Summary:PDF Full Text Request
Coal chemical industry wastewater contains high concentration of phenol. It is difficult to degrade such kind of organic wastewater with traditional biological method if left them without preprocessing. Pervaporation separation technology is used for the recovery of phenol from coal chemical industry wastewater with the advantages of low secondary pollution, less energy consumption, and easier operation. There are many kinds of pervaporation membrane materials, among them, PVDF hollow fiber membrane is widely used due to its super properties of high permeation flux, great separation performance, easy to clean and low cost. But i t also has its own drawbacks, such as their hydrophobic property, low intensity, and easily swelling.The purpose of this article is to modify PVDF membrane with two substances(Si O2/PDMS)to make up its own shortcomings. By adding modified PDMS materials, the hydrophobic properties of PVDF membrane were increased. Filling it with inorganic nanometer Si O2 particles, the mechanical strength of PVDF membrane materials were enhanced and its swelling character was declined. Si O2/PDMS/PVDF composite pervaporation membranes were prepared on PVDF hollow fiber membranes, by coating a layer of PDMS solution filled with Si O 2 through dynamic negative pressure method, in order to treat and recover phenol from coal chemical industry wastewater. Energy dispersive spectrometer(EDS), Scanning electron microscope(SEM), Fourier infrared spectrometerand(FTIR), and Contact angle instrument were used to detect the composite membranes.The results showed that the structure of Si O2/PDMS was introduced on the surface of PVDF membrane successfully, and composite membranes were prepared with the properties of high hydrophobic and tight structure.The water flux, average pore diameter and porosity, mechanical strength and swelling properties and stain resistance of composite membranes were investigated. Results indicated that by filling in inorganic silica, the flux, average pore diameter, porosity, swelling performance and the anti-pollution ability of composite membranes were all reduced. However, the intercept rate and strength of composite membrane were increased.The effect of Si O2 mass concentration and coating time on structure and property of composite membranes were also investigated. The composite membranes showed the best pervaporation performance, when the Si O2 mass concentration was 12%, the coating time was 60 min, water temperature was 50℃, flow rate was 10 L/h, pressure under membrane was-50 KPa, phenol flux was 7.16 g/(m2·h), separation factor was 4.26. In order to treat coal chemical industry wastewater containing phenol and explore pilot experiment operati ng conditions, the optimized Si O2/PDMS/PVDF composite membrane modules were used in the pervaporation of pilot experiment device, with optimized parameters of water temperature 70℃, pressure under membrane-70 kpa, cycle time 6 h, circulation flow velocity 170 L/h, phenol removal rate 77.6%. Through the improvement the system could ran stably, and pervaporation could return to good performance after cleaning the membrane modules.
Keywords/Search Tags:hollow fiber composite membranes, Si O2/PDMS/PVDF, dynamic negative pressure method, pervaporation, phenol, coal gastrification wastewater
PDF Full Text Request
Related items