Preparation And Application Of Hollow Fiber Membranes In Wastewater Treatment

This paper describes the application of membrane separation and membrane separation characteristics, and analyzes four reasons for that membrane technology has been widely used in water treatment project; describes the research and development situation of membrane separation technology at home and abroad, and focuses on the analysis of ultrafiltration technology in the state of development at home and abroad.In membrane separation technology development process, the chemical properties of membrane materials and membrane structures play a decisive role on the effect of membrane separation. This paper describes the characteristics of polymer organic PVDF membrane, analyzes the research progress and problems of PVDF membranes in water treatment, and analyzes the progress of PVDF membrane preparation and the hydrophilic modification, points that the PVDF film is excellent comprehensive performance membrane material, but because of its strong hydrophobic nature, it is easily be contaminated in the water phase separation. Membrane fouling has become a constraint to further promote the use of membrane separation technology, one of the main means to solve the membrane fouling is to prepare anti-pollution performance of the membrane, and the modification of existing membranes is a good way. Blending modification process of membrane material is simple, bringing two or more polymer blend membrane together can be integrated and balanced performance of each component, without affecting the use of the conditions required, and reduce some performance excellent but the price high raw material costs, is one of the main methods to improve the performance of PVDF membrane.. Blending modification is still hot in the after study.In order to improve the hydrophilic of PVDF ultrafiltration membrane and to enhance :ts anti-pollation capacity in the water treatment blends the PAN as a hydrophilic agent and polyvinylidene fluoride (PVDF), using phase inversion method cast process obtains blending hollow fiber, and the strength and toughness is good. Using scanning electron microscope observes the section of the hollow fiber memb ane and found that the prepared hollow fiber membrane has double-cortex structure, and from outside to inside are as follows:outer dense layer, the little finger-shaped hole supporting layer, thumb-shaped hole supporting layer, within the dense ayer. Blend membranes flux significantly increases with sodium hypochlorite solution on the post-treatment. This paper studies the ch ultrafiltration membrane. Designing orthogonal experiment optimizes the composition of casting solution and test membrane performance, points out that when the polymer concentration of 17%-19%, PVDF/PAN=5:1, additives for the PVP, and the content of 8%, DMAC for solvent, the other spinning process parameters unchanged, it can be obtained a hollow fiber ultrafiluation membrane,of pure water flux at 348-402 L/m2·h, retention of the BSA solution at 80%-85%, bubble point pressure about 0.3MPa, maximum aperture around 0.1μm, porosity of 71.4%-78.2% emical stability and anti-pcllution performance of blend membrane, test results show that the acid resistance is best, followed by oxidation and alkali worst; to join hydrophilic PAN enhances the anti-pollution performance of PVDF membrane.This paper introduces the characteristics and the research process of membrane bioreactor, and analyzes the problems to be solved of membrane bioreactor in engineering apphcat:on. The self-made PVDF PAN blend hollow fiber ultrafillration membrane:s made into curtain-type membrane modules, be placed in membrane bio-reactor, and be used in a small business sewage treatment, the PVDF PAN blend membrane flux changes:s tested, the removal effects of various pollutants for wastewater of membrane bioreactor are stuied. It analyzes the impact of the sludge concentration increase to the pollutant removal rate, and the impact of the different pumping and suspension time to the removal effects of various pollutants. Cleaning methods on membrane flux recovery effect is also studied. Experiments show that, in the stable operation, the membrane flux is stable at around 19L/m2·h, the membrane water without suspended solids, turbidity <1NTU,COD<40mg/L,BOD5<2mg/L, NH4+-N<2mg/L, to achieve the " urban sewage reclamation and reuse urban miscellaneous water quality" (GB/T18920-2002) Standard.COD removal and ammonia nitrogen removal in 93% or more, TN and TP removal rates of 47.1%-78.8% and 29%-59% respectively. When the sludge concentration of 4000-4500mg/L, sludge age of 37-44d, the sludge is still a good performance, MBR system has a comprehensive and stable sound of each pollutant removal efficiency. When the suction time is 10min and pause time is 2min, CODCr, NH4+-N and TP removal rates are of the best integrated effects,95.7%,94.1% and 52.5% respectively. After the membrane cleaning, the maximum recoverable flux is of 83.3% to a new membrane flux.