Method for modifying membrane material in membrane bioreactor

Abstract

The invention discloses a method for modifying a membrane material in a membrane bioreactor in the field of sewage treatment, which comprises the following steps: preparing membrane liquid by using polyvinylidene fluoride as the membrane material, using polyvinylpyrrolidone as a porogen, using N-Methyl-2-pyrrolidinone as an organic solvent, using sodium hexametaphosphate as a dispersing agent and using deionized water with the temperature of 25 DEG C as coagulating bath, heating the membrane liquid to the temperature of 50 DEG C and carrying out deaeration for 30 minutes under the vacuum condition of minus 50kPa after stirring so as to form uniform cast membrane liquid; uniformly adding nano TiO2 particles into the cast membrane liquid to prepare an organic-inorganic hybrid membrane by a blending method through adopting an L-S phase conversion method, wherein the added nano TiO2 particles account for 3 to 5 percent by weight of the polyvinylidene fluoride; and preparing the organic-inorganic hybrid membrane into a flat membrane or a hollow fiber membrane. The modified membrane shows obvious hydrophilcity, has excellent membrane flux and membrane separation performance and can effectively improve the problem of membrane pollution in the membrane bioreactor.

Description

technical field

[0001] The invention relates to a method in the technical field of sewage treatment, specifically using nano-TiO 2 Modification of membrane materials in membrane bioreactors. Background technique

[0002] Membrane bioreactor (MBR) is a new type of sewage treatment technology that combines traditional membrane separation technology and biological treatment technology. use. In the actual use of membrane bioreactors, due to the adsorption of separated substances on the membrane surface or the clogging of membrane pores, membrane fouling is easily caused, resulting in high energy consumption, easy clogging and short life. At present, there are three categories of methods to prevent membrane fouling and increase membrane flux: (1) increase membrane cleaning, including hydraulic cleaning and chemical cleaning, to restore membrane flux; (2) increase pretreatment measures, such as coagulation, activated carbon (3) develop anti-pollution membrane materials, or modi...

Examples

Embodiment 1

[0016] First use the hexamic acid that accounts for 20% by weight of polyvinylidene fluoride, 3% of polyvinylpyrrolidone, 77% of N-methylpyrrolidone, and 1% by weight of polyvinylidene fluoride. Sodium and deionized water at 25°C were used to prepare the membrane solution, heated to 50°C, stirred vigorously for 24 hours, and then degassed for 30 minutes under a vacuum of -50kPa to form a uniform casting solution. Then, the organic-inorganic hybrid film was prepared by the L-S phase inversion method. During the preparation process, the nano-TiO with a weight percentage of 3% of polyvinylidene fluoride was evenly added to the casting film solution by blending. 2 Particles, and finally organic-inorganic hybrid membranes are made into hollow fiber membranes for use in membrane bioreactors.

[0017] figure 1 is the three-dimensional image of the original non-modified membrane under the atomic force microscope, figure 2 It is a three-dimensional image of the hollow fiber membran...

Embodiment 2

[0019] The difference between embodiment 2 and embodiment 1 is that the nano-TiO that accounts for 4% by weight of polyvinylidene fluoride is evenly added in the casting solution by blending method 2 particle. All the other steps are the same as in Example 1.

Embodiment 3

[0021] The difference between embodiment 3 and embodiment 1 is that the nano-TiO that accounts for 4% by weight of polyvinylidene fluoride is evenly added in the casting solution by blending. 2 Particles, and finally the organic-inorganic hybrid film is made into a flat film. All the other steps are the same as in Example 1.

[0022] The modified hollow fiber membranes and flat membranes obtained in Example 2-3 and the membranes of non-modified membrane bioreactors are all placed in the membrane bioreactor under the same working condition for sewage treatment, and the treatment results are: The modified hollow fiber membrane and flat membrane have better hydrophilicity, and their anti-pollution and membrane flux are improved. After 90 days of operation, no sludge was discharged during the operation. Under different membrane suction pressures and different aeration intensities, the membrane flux and membrane filtration resistance were measured respectively. The result is that...

technical field

[0001] The invention relates to a method in the technical field of sewage treatment, specifically using nano-TiO 2 Modification of membrane materials in membrane bioreactors. Background technique

[0002] Membrane bioreactor (MBR) is a new type of sewage treatment technology that combines traditional membrane separation technology and biological treatment technology. use. In the actual use of membrane bioreactors, due to the adsorption of separated substances on the membrane surface or the clogging of membrane pores, membrane fouling is easily caused, resulting in high energy consumption, easy clogging and short life. At present, there are three categories of methods to prevent membrane fouling and increase membrane flux: (1) increase membrane cleaning, including hydraulic cleaning and chemical cleaning, to restore membrane flux; (2) increase pretreatment measures, such as coagulation, activated carbon (3) develop anti-pollution membrane materials, or modi...

Examples

Embodiment 1

[0016] First use the hexamic acid that accounts for 20% by weight of polyvinylidene fluoride, 3% of polyvinylpyrrolidone, 77% of N-methylpyrrolidone, and 1% by weight of polyvinylidene fluoride. Sodium and deionized water at 25°C were used to prepare the membrane solution, heated to 50°C, stirred vigorously for 24 hours, and then degassed for 30 minutes under a vacuum of -50kPa to form a uniform casting solution. Then, the organic-inorganic hybrid film was prepared by the L-S phase inversion method. During the preparation process, the nano-TiO with a weight percentage of 3% of polyvinylidene fluoride was evenly added to the casting film solution by blending. 2 Particles, and finally organic-inorganic hybrid membranes are made into hollow fiber membranes for use in membrane bioreactors.

[0017] figure 1 is the three-dimensional image of the original non-modified membrane under the atomic force microscope, figure 2 It is a three-dimensional image of the hollow fiber membran...

Embodiment 2

[0019] The difference between embodiment 2 and embodiment 1 is that the nano-TiO that accounts for 4% by weight of polyvinylidene fluoride is evenly added in the casting solution by blending method 2 particle. All the other steps are the same as in Example 1.

Embodiment 3

[0021] The difference between embodiment 3 and embodiment 1 is that the nano-TiO that accounts for 4% by weight of polyvinylidene fluoride is evenly added in the casting solution by blending. 2 Particles, and finally the organic-inorganic hybrid film is made into a flat film. All the other steps are the same as in Example 1.

[0022] The modified hollow fiber membranes and flat membranes obtained in Example 2-3 and the membranes of non-modified membrane bioreactors are all placed in the membrane bioreactor under the same working condition for sewage treatment, and the treatment results are: The modified hollow fiber membrane and flat membrane have better hydrophilicity, and their anti-pollution and membrane flux are improved. After 90 days of operation, no sludge was discharged during the operation. Under different membrane suction pressures and different aeration intensities, the membrane flux and membrane filtration resistance were measured respectively. The result is that...

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