Antibacterial composite nanofiltration membrane with high salt rejection rate and preparation method of antibacterial composite nanofiltration membrane

Abstract

The invention discloses an antibacterial composite nanofiltration membrane with high salt rejection rate and a preparation method of the antibacterial composite nanofiltration membrane. The composite nanofiltration membrane contains attapulgite modified by a chitosan quaternary ammonium salt. The preparation method comprises the following steps: (1) enabling a porous support layer to be in contact with a water phase solution of a compound containing two or more reactive amino groups; (2) removing the excess water phase solution on the porous support layer after water phase infiltration; (3) enabling the porous support layer after the treatment in step (2) to be in contact with an organic phase solution of an acyl chloride compound containing two or more acyl chloride groups; (4) volatilizing the organic phase solution and further enabling the porous support layer to be in contact with the water phase solution of the compound containing two or more reactive amino groups and the attapulgite modified by the chitosan quaternary ammonium salt; (5) performing heat treatment and washing with water to obtain the antibacterial composite nanofiltration membrane. The antibacterial composite nanofiltration membrane disclosed by the invention can improve antibacterial performance and salt rejection rate on the basis of keeping considerable water flux.

Description

technical field

[0001] The invention relates to the field of membrane technology, and more specifically relates to a high salt cut-off antibacterial composite nanofiltration membrane and a preparation method thereof. Background technique

[0002] As a new type of separation technology, membrane separation has the advantages of low energy consumption, high separation efficiency, and environmental protection compared with traditional separation technologies such as distillation and rectification. Nanofiltration membrane separation technology is a new pressure-driven membrane separation technology between reverse osmosis and ultrafiltration. Its rejection rate for divalent or multivalent ions and organic molecules with a molecular weight greater than 200 is generally greater than 90%, which can achieve selective separation of different substances. Therefore, relying on its unique separation characteristics, nanofiltration membranes have been widely used in water softening, sol...

Examples

Embodiment 1

[0068] The specific purification steps of the attapulgite used in the present embodiment are as follows:

[0069] Prepare an attapulgite aqueous solution with a mass concentration of 10%, add a dispersant sodium hexametaphosphate whose mass is 10% of the attapulgite mass, mechanically stir for 30 minutes, ultrasonically treat for 30 minutes, and centrifuge at 2000r / min ; The supernatant was discarded and dried in an oven at 80°C.

[0070] The specific steps of the attapulgite modification after the purification in the present embodiment are as follows:

[0071] Prepare a purified attapulgite aqueous solution with a mass concentration of 10%, add chitosan quaternary ammonium salt powder with a mass of 20% of the mass of attapulgite; at 70°C, magnetically stir for 2 hours; the above reaction solution is passed through After centrifugation (2000r / min) for a certain period of time, the supernatant was discarded; the modified attapulgite was dried in an oven at 80°C, cooled and gr...

Embodiment 2

[0075] Except that the concentration of the attapulgite modified by chitosan quaternary ammonium salt is changed to 0.004g / L in the water phase added again on the polyamide layer generated, other processing steps and test conditions are all the same as in Example 1, The test results of the prepared composite nanofiltration membrane are listed in Table 1.

Embodiment 3

[0077] Except that the concentration of the attapulgite modified by chitosan quaternary ammonium salt is changed to 0.008g / L in the aqueous phase added again on the polyamide layer generated, other processing steps and test conditions are all the same as in Example 1, The test results of the prepared composite nanofiltration membrane are listed in Table 1.

technical field

[0001] The invention relates to the field of membrane technology, and more specifically relates to a high salt cut-off antibacterial composite nanofiltration membrane and a preparation method thereof. Background technique

[0002] As a new type of separation technology, membrane separation has the advantages of low energy consumption, high separation efficiency, and environmental protection compared with traditional separation technologies such as distillation and rectification. Nanofiltration membrane separation technology is a new pressure-driven membrane separation technology between reverse osmosis and ultrafiltration. Its rejection rate for divalent or multivalent ions and organic molecules with a molecular weight greater than 200 is generally greater than 90%, which can achieve selective separation of different substances. Therefore, relying on its unique separation characteristics, nanofiltration membranes have been widely used in water softening, sol...

Examples

Embodiment 1

[0068] The specific purification steps of the attapulgite used in the present embodiment are as follows:

[0069] Prepare an attapulgite aqueous solution with a mass concentration of 10%, add a dispersant sodium hexametaphosphate whose mass is 10% of the attapulgite mass, mechanically stir for 30 minutes, ultrasonically treat for 30 minutes, and centrifuge at 2000r / min ; The supernatant was discarded and dried in an oven at 80°C.

[0070] The specific steps of the attapulgite modification after the purification in the present embodiment are as follows:

[0071] Prepare a purified attapulgite aqueous solution with a mass concentration of 10%, add chitosan quaternary ammonium salt powder with a mass of 20% of the mass of attapulgite; at 70°C, magnetically stir for 2 hours; the above reaction solution is passed through After centrifugation (2000r / min) for a certain period of time, the supernatant was discarded; the modified attapulgite was dried in an oven at 80°C, cooled and gr...

Embodiment 2

[0075] Except that the concentration of the attapulgite modified by chitosan quaternary ammonium salt is changed to 0.004g / L in the water phase added again on the polyamide layer generated, other processing steps and test conditions are all the same as in Example 1, The test results of the prepared composite nanofiltration membrane are listed in Table 1.

Embodiment 3

[0077] Except that the concentration of the attapulgite modified by chitosan quaternary ammonium salt is changed to 0.008g / L in the aqueous phase added again on the polyamide layer generated, other processing steps and test conditions are all the same as in Example 1, The test results of the prepared composite nanofiltration membrane are listed in Table 1.

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