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Deep cleaning method for unrecoverable pollution in micro/ultrafiltration membrane based on green solvent

A green solvent and deep cleaning technology, applied in the field of membrane separation, can solve the problems of unable to meet the demand of water production, unrecoverable pollution and membrane binding force, etc., to achieve both reaction rate and safety, save membrane replacement costs, reduce carbon footprint effect

Active Publication Date: 2022-04-05
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, the pollution that cannot be removed by conventional chemical cleaning is defined as "non-recoverable pollution", also known as "permanent pollution". Permeability will gradually decrease until it cannot meet the water production demand and ultimately determines the service life of the membrane
[0004] According to literature research, there is currently no effective method for cleaning the non-recoverable contamination of MBR micro / ultrafiltration membranes
Although the non-recoverable pollution component is usually unknown, it is characterized by a strong binding force with the membrane, so it is difficult to wash it out by conventional chemical cleaning. bonding force

Method used

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  • Deep cleaning method for unrecoverable pollution in micro/ultrafiltration membrane based on green solvent
  • Deep cleaning method for unrecoverable pollution in micro/ultrafiltration membrane based on green solvent
  • Deep cleaning method for unrecoverable pollution in micro/ultrafiltration membrane based on green solvent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Pre-cleaning of polluted micro / ultrafiltration membranes: Soak and clean the polluted PVDF ultrafiltration membranes with 0.5% sodium hypochlorite for 1.5 hours, then with 2.0% oxalic acid for 1.5 hours, and then rinse with deionized water to remove excess agents on the surface.

[0029] Wherein, the PVDF membranes cleaned by Examples and Comparative Examples are all micro / ultrafiltration membranes (generally For membranes that have been used for 5 to 7 years)

[0030] through figure 1 It can be seen from the scanning electron microscope observation shown that after pre-cleaning, some pollutants attached to the surface are detached from the membrane surface.

Embodiment 2

[0032] Green solvent deep cleaning of polluted micro / ultrafiltration membrane: Blow the pre-cleaned PVDF ultrafiltration membrane with nitrogen for 3.0min, then soak it in green solvent and placed in a constant temperature shaking shaker (100rpm) at 40°C for 4.0h to make the membrane fully contact with the green solvent. The green solvent in the membrane is fully washed out, and the PVDF ultrafiltration membrane after deep cleaning is obtained.

[0033] through figure 1 It can be seen from the scanning electron microscope observation that the membrane surface is further cleaned and the membrane surface is relatively smoother.

[0034] through figure 2 The three-dimensional fluorescence spectrum shown can be obtained, and the unrecoverable pollutants in the membrane are washed out, and the peak of pollutants appears in the humic acid-like fluorescence spectrum region.

Embodiment 3

[0036] Green solvent deep cleaning of polluted micro / ultrafiltration membrane: Gently blow the pre-cleaned PVDF ultrafiltration membrane with nitrogen for 3.0min, then soak it in the green solvent dimethyl isosorbide DMI, and place it at 60°C for constant temperature oscillation In the shaker (100rpm) for 6.0h, make the membrane fully contact with the green solvent. After the treatment is completed, use deionized water to backwash the contaminated membrane after solvent treatment for 3.0h, and fully wash out the green solvent remaining in the membrane. That is, the PVDF ultrafiltration membrane after deep cleaning is obtained.

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Abstract

The invention provides a deep cleaning method for unrecoverable pollution in a micro / ultrafiltration membrane based on a green solvent, which comprises the following steps: (1) pre-cleaning a polluted micro / ultrafiltration membrane to remove reversible and irreversible pollution on the surface of the membrane and in membrane holes; (2) slightly blowing the pre-cleaned polluted membrane with nitrogen, then soaking the pre-cleaned polluted membrane in a green solvent, enabling the membrane to be in full contact with the green solvent, and rapidly transferring the membrane into deionized water after the treatment is completed; and (3) backwashing the polluted membrane subjected to solvent treatment by using deionized water, and fully washing out the residual green solvent in the membrane to obtain the deeply cleaned polluted micro / ultrafiltration membrane. According to the method, reversible and irreversible pollution on the membrane surface / in membrane holes is removed through conventional chemical cleaning, then unrecoverable pollution is washed out through a specific solvent, finally, the membrane flux is recovered to a new membrane level through post-treatment, and on the premise that the effluent quality is guaranteed and secondary pollution is not generated, the recovery rate of the membrane is improved. The washing-out of unrecoverable pollutants and the recovery of membrane flux are realized.

Description

technical field [0001] The invention relates to the technical field of membrane separation, in particular to a method for deep cleaning of unrecoverable pollution in micro / ultrafiltration membranes based on green solvents. Background technique [0002] Membrane bioreactor (MBR), as an efficient sewage treatment technology integrating biological treatment and membrane separation, has many advantages over traditional activated sludge biological treatment process. MBR uses micro / ultrafiltration membrane modules for solid-liquid separation, which is better than secondary sedimentation tanks; MBR's longer sludge age makes it have a higher sludge concentration, high pollutant removal efficiency, and good effluent quality. At the same time, it has a certain tolerance to fluctuations in water quality and quantity, and its operation is relatively stable; its structure is highly integrated, its footprint is small, and it is easy to equipment and standardize. Due to the complex water ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D65/06B01D65/02
CPCY02W10/10
Inventor 戴若彬王志伟田晨昕
Owner TONGJI UNIV