阅读说明：本技术 一种界面微流法制备超薄复合膜的制备方法 (Preparation method for preparing ultrathin composite membrane by interfacial microfluidization method ) 是由 张国亮 李洋 于 2019-08-29 设计创作，主要内容包括：本发明公开了一种界面微流法制备超薄复合膜的制备方法,所述的方法为：将预处理的中空纤维超滤膜浸渍在盛有哌嗪的水溶液中,然后向所述的中空纤维超滤膜中通入均苯三甲酰氯的正己烷溶液,持续通入15～180s,发生聚合反应,所述的中空纤维超滤膜的内表面生成超薄的聚酰胺层,然后用正己烷溶剂清洗覆有聚酰胺层的中空纤维超滤膜的内表面,再进行干燥后得到超薄复合膜。本发明并非相继在膜的一侧放上哌嗪与酰氯,而是在膜的内外两侧放置,从而在膜的界面处合成了超薄的聚酰胺层,大大提高了水通量,避免了膜的转移,制备超薄膜的同时无明显缺陷,而且原料可回收,减少了浪费。(the invention discloses a preparation method for preparing an ultrathin composite membrane by an interfacial microfluidization method, which comprises the following steps: dipping a pretreated hollow fiber ultrafiltration membrane in an aqueous solution containing piperazine, introducing an n-hexane solution of trimesoyl chloride into the hollow fiber ultrafiltration membrane, continuously introducing for 15-180 s to generate a polymerization reaction, generating an ultrathin polyamide layer on the inner surface of the hollow fiber ultrafiltration membrane, cleaning the inner surface of the hollow fiber ultrafiltration membrane covered with the polyamide layer by using an n-hexane solvent, and drying to obtain the ultrathin composite membrane. The invention does not place piperazine and acyl chloride on one side of the membrane in sequence, but places the piperazine and the acyl chloride on the inner side and the outer side of the membrane, so that an ultrathin polyamide layer is synthesized at the interface of the membrane, the water flux is greatly improved, the transfer of the membrane is avoided, no obvious defect exists when the ultrathin membrane is prepared, the raw materials can be recycled, and the waste is reduced.)

1. A method for preparing an ultrathin composite film by an interfacial microfluidization method is characterized in that: the method comprises the following steps:

Dipping a pretreated hollow fiber ultrafiltration membrane in an aqueous solution containing piperazine, introducing an n-hexane solution of trimesoyl chloride into the hollow fiber ultrafiltration membrane, continuously introducing for 15-180 s to generate a polymerization reaction, generating an ultrathin polyamide layer on the inner surface of the hollow fiber ultrafiltration membrane, cleaning the inner surface of the hollow fiber ultrafiltration membrane covered with the polyamide layer by using an n-hexane solvent, and drying to obtain an ultrathin composite membrane; the mass fraction of the piperazine aqueous solution is 0.05-5%, and the mass fraction of the n-hexane solution of trimesoyl chloride is 0.01-1%.

2. The method of claim 1, wherein: the pretreatment process of the hollow fiber ultrafiltration membrane comprises the following steps: the hollow fiber ultrafiltration membrane is cleaned by mixed solution of water and methanol with the volume ratio of 1:1, then soaked in deionized water for one day, and then dried for standby.

3. The method of claim 1, wherein: the ultrafiltration membrane is made of polyvinylidene fluoride, polypropylene, polyacrylonitrile, polyethylene, polyvinyl chloride, polysulfone, polyether sulfone or polyimide.

4. The method of claim 1, wherein: the drying temperature is 60-90 ℃, and the drying time is 5-20 min.

5. The method of claim 1, wherein: and the normal hexane solution of trimesoyl chloride is pumped into the hollow fiber ultrafiltration membrane by connecting a peristaltic pump with a flow pipeline.

6. The method of claim 5, wherein: the flow pipeline is externally connected with a normal hexane flow pipeline, the flow pipeline of the normal hexane solution of trimesoyl chloride and the normal hexane flow pipeline are connected in parallel through a Y-shaped or T-shaped connecting pipeline and then connected with the hollow fiber ultrafiltration membrane in series, and the connection part of the ports passes through.

7. The method of claim 1, wherein: the flow rate of the n-hexane solution of trimesoyl chloride is 20-200 mu L/hr.

8. The method of claim 1, wherein: the length of the hollow fiber membrane is 5-20 cm, and the number of the hollow fiber membrane is 10-30.

Technical Field

The invention relates to a device for preparing an ultrathin composite membrane by an interfacial microfluidics method and application, belonging to the technical field of functional membrane preparation and separation application.

Background

In 1972, Cadotte firstly applies an interfacial polymerization method to prepare a high-performance reverse osmosis composite membrane NS100, the salt rejection rate and the water flux of the membrane are greatly improved compared with those of the membrane prepared by the L-S method, and 90 percent of the current reverse osmosis/nanofiltration membranes worldwide are produced by the interfacial polymerization method. The general method is to reduce the thickness of the membrane, reduce the mass transfer resistance of the membrane and simultaneously greatly improve the water treatment efficiency, and the composite nanofiltration membrane with the ultrathin polyamide layer is prepared by polymerizing two-phase liquid at the interface of the ultrafiltration membrane, so that the method avoids the transfer of the membrane, has no obvious defect while preparing the ultrathin membrane, can recover raw materials and reduces the waste. Compared with the traditional interfacial polymerization membrane, the flux of the membrane is increased under the condition of not adding new materials, and another way is provided for preparing a new generation of high-flux membrane.

Disclosure of Invention

in order to overcome the defects in the prior art, the invention aims to provide a novel method for preparing an ultrathin composite membrane by using an interfacial microfluidization method to realize high-efficiency water treatment, and the method is applied to seawater desalination.

The technical scheme adopted by the invention is as follows:

A method for preparing an ultrathin composite membrane by an interfacial microfluid method comprises the following steps:

Dipping a pretreated hollow fiber ultrafiltration membrane in an aqueous solution containing piperazine, introducing an n-hexane solution of trimesoyl chloride into the hollow fiber ultrafiltration membrane, continuously introducing for 15-180 s to generate a polymerization reaction, generating an ultrathin polyamide layer on the inner surface of the hollow fiber ultrafiltration membrane, cleaning the inner surface of the hollow fiber ultrafiltration membrane covered with the polyamide layer by using an n-hexane solvent, and drying to obtain an ultrathin composite membrane; the mass fraction of the piperazine aqueous solution is 0.05-5%, and the mass fraction of the n-hexane solution of trimesoyl chloride is 0.01-1%.

Further, the pretreatment process of the hollow fiber ultrafiltration membrane comprises the following steps: the hollow fiber ultrafiltration membrane is cleaned by mixed solution of water and methanol with the volume ratio of 1:1, then soaked in deionized water for one day, and then dried for standby.

Furthermore, the ultrafiltration membrane is made of polyvinylidene fluoride, polypropylene, polyacrylonitrile, polyethylene, polyvinyl chloride, polysulfone, polyether sulfone, polyimide and the like.

Further, the drying temperature is 60-90 ℃, and the drying time is 5-20 min.

The normal hexane solution of trimesoyl chloride is pumped into the hollow fiber ultrafiltration membrane by connecting a peristaltic pump with a flow pipeline.

The normal hexane flow pipeline is externally connected with the flow pipeline and used for introducing normal hexane into the hollow fiber ultrafiltration membrane to clean the inner wall after the reaction is finished, and the flow pipeline of the normal hexane solution of trimesoyl chloride and the normal hexane flow pipeline are connected in parallel through a Y-shaped or T-shaped connecting pipeline and then connected with the hollow fiber ultrafiltration membrane in series.

Furthermore, the joints of the ports at the two ends of the hollow fiber ultrafiltration membrane are sealed by epoxy resin glue.

Further, the flow rate of the n-hexane solution of trimesoyl chloride is 20-200 mu L/hr.

Furthermore, the length of the hollow fiber membrane is 5-20 cm, and the number of the hollow fiber membrane is 10-30.

Compared with the prior art, the invention has the advantages that: the invention does not place piperazine and acyl chloride on one side of the membrane in sequence, but places the piperazine and the acyl chloride on the inner side and the outer side of the membrane, so that an ultrathin polyamide layer is synthesized at the interface of the membrane, the water flux is greatly improved, the transfer of the membrane is avoided, no obvious defect exists when the ultrathin membrane is prepared, the raw materials can be recycled, and the waste is reduced.

The invention is further illustrated by the following examples.

Drawings

Figure 1 SEM image of composite nanofiltration membrane surface inside hollow fiber membrane.

FIG. 2 is a diagram of an experimental device, 1 is a n-hexane liquid storage tank, 2 is a n-hexane solution storage tank of trimesoyl chloride, 3 is a Y-shaped connecting pipeline, 4 is a piperazine aqueous solution, 5 is a hollow fiber ultrafiltration membrane, 6 is a collecting device, 7 is a peristaltic pump.

Detailed Description

The present invention will be described in detail below with reference to specific examples, but the present invention is not limited to the following examples, and various modifications and implementations are included within the technical scope of the present invention without departing from the content and scope of the present invention.

materials and reagents required in the preparation of the composite membrane:

Polysulfone (PSF) shanghai eosino photochemical plant, polyvinylidene fluoride (PVDF) shanghai eosino photochemical plant, Polyethersulfone (PES) shanghai eosino photochemical plant, polypropylene (PP) shanghai eosino photochemical plant, Polyacrylonitrile (PAN) shanghai eosino photochemical plant, polyvinyl chloride (PVC) shanghai eosino photochemical plant, anhydrous methanol alatin reagent (shanghai) limited, trimesoyl chloride (TMC), anhydrous piperazine (PIP) alatin reagent (shanghai) limited, sodium sulfate (Na)₂SO₄) Magnesium sulfate (MgSO)₄) Magnesium chloride (MgCl)₂) Sodium nitrate (NaNO)₃) Sodium chloride (NaCl), N-Dimethylformamide (DMF), N-methylpyrrolidone (NMP), Dimethylacetamide (DMAC) by national medicine group chemical reagent Co.

example 1

Pretreatment of a base film: cutting the hollow fiber polysulfone ultrafiltration membrane into small sections with the length of 20cm, and mixing the small sections with water and methanol water 1: the solution of 1 is washed for three times respectively, soaked in water for one day and then dried for standby.

The device is built: prepare diameter 2.5cm, long 18 cm's glass long tube, glass long tube both ends opening, be equipped with inlet and liquid outlet and the inside intercommunication of glass long tube on the lateral wall, arrange the glass long tube in with the hollow fiber membrane group that 10 hollow fiber membranes constitute to seal the gap of port department between with epoxy with between the glass long tube and between glass long tube and the hollow fiber membrane, the glass long tube in constitute inclosed space, treat to guarantee the inside unblocked of each hollow fiber membrane in the hollow fiber membrane group after the glue is done, then with the normal hexane solution liquid storage pot and the normal hexane liquid storage pot connection peristaltic pump of trimesoyl chloride, then be connected with hollow fiber membrane group one end after parallelly connected through Y type connecting tube.

Preparing a nanofiltration membrane: preparing a piperazine aqueous solution with the mass fraction of 2% as an A solution, and preparing a trimesoyl chloride n-hexane solution with the mass fraction of 0.05% as a B solution. Closing the liquid outlet of the glass long tube, introducing the solution A into the glass long tube through the liquid inlet until the whole glass long tube is fully distributed, closing the liquid inlet, keeping the liquid for 30s, injecting the solution B into the glass long tube through a peristaltic pump at the speed of 141 mu L/hr, stopping the operation after 2min, changing the direction of the inner part of the hollow fiber membrane, introducing normal hexane to remove the redundant solution B, discharging the solution A in the glass long tube through the liquid outlet, taking out the hollow fiber membrane, placing the hollow fiber membrane into the air, keeping the hollow fiber membrane for 3min, then placing the hollow fiber membrane into an oven at 80 ℃ for drying for 5min, and placing the.

And (3) performance testing: the water flux of the membrane is 17.6L/(m) under 0.6MPa and 25L/h²H.bar) with a sodium sulfate rejection of 95.5%.

Example 2

Pretreatment of a base film: cutting the hollow fiber polysulfone ultrafiltration membrane into small sections with the length of 20cm, and mixing the small sections with water and methanol water 1: the solution of 1 is washed for three times respectively, soaked in water for one day and then dried for standby.

The device is built:

Preparing a glass long tube with the diameter of 2.5cm and the length of 18cm, opening two ends and opening two openings at the column side, arranging a hollow fiber membrane group consisting of 10 hollow fiber membranes in the glass long tube, sealing gaps at the port parts between the glass long tubes and between the glass long tube and the hollow fiber membranes by using epoxy resin, forming a closed space in the glass long tube, ensuring the smoothness of the interior of each hollow fiber membrane in the hollow fiber membrane group after glue is dried, connecting a n-hexane solution storage tank and a n-hexane solution storage tank of trimesoyl chloride with a peristaltic pump, and connecting the n-hexane solution storage tank and the n-hexane solution storage tank of trimesoyl chloride with one end of the hollow fiber membrane group after the n-hexane solution storage tank.

Preparing a nanofiltration membrane:

Preparing a piperazine aqueous solution with the mass fraction of 2% as an A solution, and preparing a trimesoyl chloride n-hexane solution with the mass fraction of 0.05% as a B solution. Closing the liquid outlet of the glass long tube, introducing the solution A into the glass long tube through the liquid inlet until the whole glass long tube is fully distributed, closing the liquid inlet, keeping the liquid for 30s, injecting the solution B into the glass long tube through a peristaltic pump at the speed of 141 mu L/hr, stopping the operation after 30s, changing the direction of the inner part of the hollow fiber membrane, introducing normal hexane to remove the redundant solution B, discharging the solution A in the glass long tube through the liquid outlet, taking out the hollow fiber membrane, keeping the hollow fiber membrane in the air for 3min, then placing the hollow fiber membrane into an oven at 80 ℃ for drying for 5min, and placing the obtained ultrathin composite membrane in a.

and (3) performance testing: the water flux of the membrane is 19.8L/(m) under 0.6MPa and 25L/h²H.bar) with a sodium sulfate rejection of 95.5%.

Example 3

Pretreatment of a base film: cutting the hollow fiber polysulfone ultrafiltration membrane into small sections with the length of 20cm, and mixing the small sections with water and methanol water 1: the solution of 1 is washed for three times respectively, soaked in water for one day and then dried for standby.

The device is built:

Preparing a glass long tube with the diameter of 2.5cm and the length of 18cm, opening two ends and opening two openings at the column side, arranging a hollow fiber membrane group consisting of 10 hollow fiber membranes in the glass long tube, sealing gaps at the port parts between the glass long tubes and between the glass long tube and the hollow fiber membranes by using epoxy resin, forming a closed space in the glass long tube, ensuring the smoothness of the interior of each hollow fiber membrane in the hollow fiber membrane group after glue is dried, connecting a n-hexane solution storage tank and a n-hexane solution storage tank of trimesoyl chloride with a peristaltic pump, and connecting the n-hexane solution storage tank and the n-hexane solution storage tank of trimesoyl chloride with one end of the hollow fiber membrane group after the n-hexane solution storage tank.

preparing a nanofiltration membrane:

Preparing a piperazine aqueous solution with the mass fraction of 2% as an A solution, and preparing a trimesoyl chloride n-hexane solution with the mass fraction of 0.1% as a B solution. Closing the liquid outlet of the glass long tube, introducing the solution A into the glass long tube through the liquid inlet until the whole glass long tube is fully distributed, closing the liquid inlet, keeping the liquid for 30s, injecting the solution B into the glass long tube through a peristaltic pump at the speed of 141 mu L/hr, stopping the operation after 2min, changing the direction of the inner part of the hollow fiber membrane, introducing normal hexane to remove the redundant solution B, discharging the solution A in the glass long tube through the liquid outlet, taking out the hollow fiber membrane, placing the hollow fiber membrane into the air, keeping the hollow fiber membrane for 3min, then placing the hollow fiber membrane into an oven at 80 ℃ for drying for 5min, and placing the.

Performance ofAnd (3) testing: the water flux of the membrane is 15.6L/(m) under 0.6MPa and 25L/h²h.bar) with a sodium sulfate rejection of 95.5%.