CN107815668A - Rotary atomic layer deposition reactor for batch modification of hollow fiber membrane - Google Patents

Abstract

The invention is a rotary atomic layer deposition device for batch modification of hollow fiber membranes, which is used to realize the rotation and uniform deposition of hollow fiber membranes in a cavity. The rotary reactor includes a chamber and an upper cover. The top of the chamber and the upper cover are sealed by a sealing ring to ensure that the whole device can reach the vacuum degree required by the experiment. The motor with the magnet is fixed on the cover of the cavity, and the interaction force of the magnet is used to make the magnet inside the cavity rotate with the rotation of the motor. Then drive the porous turntable to rotate. The hollow fiber membranes are fixed on a porous turntable. By adjusting the motor speed, the hollow fiber membrane is driven to rotate, so that the reactant pulsed into the cavity is evenly diffused in the cavity and evenly deposited on the surface of the membrane. The device of the invention speeds up the diffusion of the reactant by rotating the sample, so that the entire cavity is uniformly filled, thereby realizing the purpose of depositing modified fiber materials in large quantities, and has the advantages of high efficiency and high output.

Description

A Rotary Atomic Layer Deposition Reactor for Batch Modification of Hollow Fiber Membranes

technical field

The patent of the present invention relates to an atomic layer deposition reactor, which provides a more uniform and controllable rotary atomic layer deposition reactor for modifying the surface of hollow fibers in batches.

Background technique

Polymer porous separation materials play an important role in water treatment, oil-water separation, particulate matter filtration and other fields. Compared with flat-sheet membranes, hollow fiber membranes have many advantages, such as larger effective filtration surface area per unit volume, simple module manufacturing, no need for feed and permeate spacers, and simpler pretreatment and maintenance. Therefore, hollow fiber membranes have potential applications in chemical wastewater treatment, blood oxygenation, biomedical materials for hemodialysis, and food processing industries. In order to achieve the desired goal, it is necessary to hydrophilize the surface properties of polymer membrane materials by physical or chemical methods. However, the traditional methods of surface modification of polymer materials, such as chemical modification, filling modification, blending modification, etc., require a large number of chemical reagents, the modification process is cumbersome, and the performance of porous materials after modification has little room for improvement. The modification is incomplete, and precise control of the pore size cannot be achieved. More importantly, the generation of a large amount of organic wastewater greatly increases the difficulty and economic cost of the subsequent treatment process.

Atomic layer deposition (ALD) is an advanced ultra-thin film deposition technology. Due to its self-limiting reaction process, the deposited layer has good conformality and can achieve sub-nanometer thickness control. . Because it can achieve uniform and conformal deposition in complex three-dimensional channels at a relatively low temperature, it has gradually become an important means of modifying polymeric porous separation materials.

Compared with the traditional membrane surface modification method, after the hydrophilic modification of the hydrophobic membrane surface by atomic layer deposition oxide hydrophilic modification, its uniformity and shape retention are good, the hydrophilicity is significantly increased, and the ability to resist protein contamination Enhanced; by changing the number of depositions, the permeability and rejection rate can be adjusted step by step, so the modification of hollow fiber membranes by ALD technology has commercial application prospects.

However, most of the atomic layer deposition reactors currently used are fixed chambers, the deposition chamber is small, and the substrate is in a static state in the chamber. Dead angles are prone to appear during the deposition reaction process, and the reactants diffuse unevenly, resulting in The deposition is uneven; and the sample capacity is small, and the production efficiency is low, which limits the scope of use and output. Therefore, it is urgent to develop a new type of reaction chamber to solve the problem that ALD is not suitable for mass deposition and modification of fibrous materials with high filtration area.

Contents of the invention

In order to solve the above technical problems, the patent of the present invention provides an atomic layer deposition rotary reactor suitable for mass deposition of modified hollow fiber membranes, which can uniformly and efficiently carry out hydrophilic modification of the membrane surface and realize the improvement of separation performance.

To achieve the above object, the present invention's scheme is as follows:

A rotary atomic layer deposition reactor for batch modification of hollow fiber membranes, including a chamber and an upper cover, the top of the chamber and the upper cover are sealed and connected by a sealing ring, and the bottom of the chamber is provided with an inlet pipe and an outlet pipe; with The motor of the magnet is fixed on the top of the upper cover, and the motor drives the magnet to rotate through the rotating shaft; there is the same magnet in the cavity, and under the interaction force of the magnet, the magnet in the cavity rotates with the rotation of the motor; the bracket is fixed in the cavity On the side wall, the magnet is fixed on the bracket through the rotating shaft; the end of the rotating shaft is connected with the porous rotating disk, and the hollow fiber membrane is suspended on the porous rotating disk.

Wherein, the holes in the porous turntable are arranged in concentric circles, and the hollow fiber membrane is suspended on the porous turntable through the raw material belt. The sealing ring is a fluorine rubber O-ring. The bracket is fixed on the side wall of the cavity with screws, which is convenient for putting in and taking out samples.

The invention also discloses a process for performing atomic layer deposition reaction in a rotary atomic layer deposition reactor for batch modification of hollow fiber membranes. The atomic layer deposition steps are as follows:

Step 1. The chamber (1) is heated up to the atomic layer deposition reaction temperature, the motor (6) is turned on, and the rotation speed is adjusted;

Step 2. Using high-purity nitrogen as the carrier gas, the precursor titanium tetrachloride is pulsed into the cavity (1) through the inlet pipe (10) and stayed for a period of time; the precursor gas is stirred under the rotation of the hollow fiber membrane (9) Uniformly dispersed in the cavity (1) and fully contacted with the hollow fiber membrane (9), a monomolecular layer chemical adsorption reaction occurs on the surface of the membrane, and then nitrogen gas is injected for 200s to purge the excess reactants and by-products, and the (11) discharge system;

Step 3. Then continue to use high-purity nitrogen as the carrier gas, feed the precursor oxygen source H ₂ O, and pulse the H ₂ O into the chamber (1) through the inlet pipe (10) and stay for a period of time; the precursor gas is in the hollow The fiber membrane (9) is evenly dispersed in the cavity (1) under the rotating stirring, and fully contacts with the hollow fiber membrane (9), and a monomolecular layer chemical reaction occurs with the titanium tetrachloride adsorbed on the membrane surface, and then nitrogen gas is introduced Excessive reactants and by-products are purged for 200s, and the system is discharged from the outlet pipe (11); after the completion of steps 2 and 3, it is a cyclic atomic layer deposition reaction;

Step 4. After repeating the atomic layer deposition reaction for 50-200 cycles, remove the upper cover (5), and the screws connecting the support (8) and the cavity (1), and then place the porous hollow fiber membrane (9) The turntable (2) is taken out.

in:

The pulse time of the precursor pulse entering the cavity (1) is 0.1-0.5s, and the residence time is 50-100s. The number of membrane filaments hanging the hollow fiber membrane (9) is 500-1000, and the modified outer surface area is 1-2m ² . The speed adjustment range of the motor (6) is 10-60r/min. The temperature of the cavity (1) for atomic layer deposition reaction is 80-150°C.

The invention designs to fix the hollow fiber membrane on the turntable, and by adjusting the motor speed, the sample membrane is driven to rotate, so that the reactant pulsed into the cavity diffuses evenly in the cavity and deposits evenly on the membrane surface. Throughput can be increased by increasing chamber size. The rotational speed can be adjusted to suit different deposition conditions.

Beneficial effect:

1. By expanding the reaction chamber and increasing the filling area of the membrane, the loading capacity of the hollow fiber membrane is increased, and the output and efficiency are improved;

2. The deposition reaction adopts the principle of magnetic induction. By rotating the sample, the reactants can be evenly diffused, so that they can be evenly adsorbed on the surface of the film, avoiding the problem of uneven adsorption when the substrate is standing still, so as to ensure the uniformity of deposition.

3. The rotation adopts the principle of magnetic induction to avoid adding redundant stirring system in the cavity. Realize mass production and improve production efficiency.

Description of drawings

Figure 1 is a front view of the apparatus of the present invention. 1: cavity, 2: porous turntable, 3: magnet, 4: sealing ring, 5: upper cover, 6: motor, 7: rotating shaft, 8: bracket, 9: hollow fiber membrane, 10: inlet pipe, 11: outlet trachea.

Figure 2 is a left side view of the apparatus of the present invention.

Figure 3 is a top view of the apparatus of the present invention.

Fig. 4 is a schematic diagram of the perforated turntable of the device of the present invention.

Fig. 5 is the SEM image of the hollow fiber membrane modified in batches by the rotating atomic layer deposition reactor in Example 1, the image a is the original membrane; the images b-d are 50, 100, and 200 times of deposition, respectively.

6 is a diagram of the deposition thickness of _TiO2 deposited on a silicon wafer obtained by different times of deposition reactions in Example 1, and the times of deposition reactions are 50 times, 100 times, 150 times, and 200 times, respectively.

Detailed ways

The present invention is further explained in conjunction with examples. The following examples are only used to illustrate the present invention, but are not intended to limit the scope of the present invention.

A rotary atomic layer deposition reactor for batch modification of hollow fiber membranes, comprising a cavity (1) and an upper cover (5), the top of the cavity (1) and the upper cover (5) are sealed by a sealing ring (4) connection, the bottom of the cavity (1) is provided with an air inlet pipe (10) and an air outlet pipe (11); the motor (6) with a magnet (3) is fixed on the top of the upper cover (5), and the motor (6) passes through the shaft ( 7) Drive the magnet (3) to rotate; there is the same magnet (3) in the cavity (1), under the interaction force of the magnets, the magnet (3) in the cavity (1) follows the movement of the motor (6) Turn and rotate; the bracket (8) is fixed on the side wall of the cavity (1), and the magnet (3) is fixed on the bracket (8) through the rotating shaft (7); the end of the rotating shaft (7) is connected to the porous turntable (2), hollow The fiber membrane (9) is suspended on the porous turntable (2). The holes in the porous turntable (2) are arranged in concentric circles, and the hollow fiber membrane (9) is suspended on the porous turntable (2) through the raw material belt. The sealing ring (4) is a fluorine rubber O-ring. The bracket (8) is fixed on the side wall of the cavity (1) with screws.

Firstly, the porous rotating disk (2) and the magnet (3) are fixed on the bracket (8) through the rotating shaft (7), and the hollow fiber membrane (9) is suspended on the porous rotating disk (2). Then fix the bracket (8) in the cavity (1) with screws, place the sealing ring (4) on the top of the cavity, put the upper cover (5) with the motor (6) on the cavity (1), In order to achieve the sealing effect. Turn on the motor (6) to rotate the magnet (3), which drives the porous turntable (2) connected to the magnet (3) to rotate, and the hollow fiber membrane (9) starts to rotate. After adjusting the speed, vacuuming and deposition experiments are carried out.

Example 1

Hang the hollow fiber membrane (9) on the porous turntable (2) and put it into the cavity (1), the number of membrane filaments is 500, and the modified outer surface area is 1m ² . Adjust the motor speed to 20r/min, raise the temperature of cavity 1 to 100°C, and keep it there for 60 minutes, so that the temperature and pressure in the cavity (1) remain stable. Precursor A (titanium tetrachloride) and oxygen source B (H ₂ O) were respectively packed in precursor cylinders and stored at room temperature. The nitrogen flow rate was 30 sccm, and the two precursors were subjected to atomic layer deposition reactions with high-purity nitrogen as the carrier gas. The atomic layer deposition reaction is carried out on the surface of the hollow fiber membrane (9) by feeding titanium tetrachloride first, and then passing an oxygen source H ₂ O to carry out the atomic layer deposition reaction on the surface of the hollow fiber membrane (9). In order to measure the deposition effect at different positions of the cavity (1), silicon wafers are suspended at three different positions of the upper, middle and bottom of the cavity (1) and the atomic layer deposition reaction is carried out simultaneously.

First, titanium tetrachloride is pulsed into the cavity (1) from the gas inlet (10), the pulse time of the precursor is 0.25s, and the residence time is set to 50s, and the precursor gas is uniform under the rotation and stirring of the hollow fiber membrane (9). Dispersed in the cavity (1) and in full contact with the hollow fiber membrane (9), a monomolecular layer chemical adsorption reaction occurs on the membrane surface. After the deposition reaction, the excess reactants and by-products are purged with nitrogen and discharged from the system through the outlet pipe (11), and the nitrogen purge time is set to 200s. Then, H ₂ O is fed into the atomic layer deposition reaction under the same conditions. H ₂ O is pulsed into the cavity (1) from the gas inlet (10), the pulse time of the precursor is 0.25s, and the residence time is set to 50s, and then Nitrogen was introduced for purging, and the purging time was set to 200s. Titanium tetrachloride and H ₂ O are respectively subjected to atomic layer deposition to complete a cycle of atomic layer deposition reaction. The atomic layer deposition reaction was repeated for 50, 100, 150, and 200 cycles. After the experiment is over, remove the upper cover (5), then remove the screws connecting the bracket (8) and the cavity (1), and take out the porous turntable (2) with the hollow fiber membrane (9) suspended thereon.

Fig. 5 is an SEM image of hollow fiber membranes (9) modified in batches by a rotating atomic layer deposition reactor in this example. It can be seen from the figure that as the number of depositions increases, some small particles gradually appear on the surface. The number of depositions continued to increase, the membrane surface was gradually covered by nanoparticles, and _TiO2 was successfully deposited on the surface of the hollow fiber membrane (9). And by controlling the number of cycles of atomic layer deposition, the thickness of the deposited layer can be precisely regulated.

FIG. 6 is the deposition thickness of TiO ₂ on the surface of the silicon wafer after different times of deposition reactions in this embodiment. It is calculated that the growth rate of deposited TiO ₂ on the surface of silicon wafer is about 1.5 Å/cycle, and the difference in deposition thickness at different positions is small at the same deposition times, and the deposition is relatively uniform within the error range.

Example 2

The atomic layer deposition process was the same as that of Example 1, except that the process conditions were different: the number of membrane filaments hanging from the hollow fiber membrane (9) was 800, and the modified outer surface area was 1.5 m ² . Adjust the rotation speed of the motor to 10r/min, and the temperature of the cavity (1) to 150°C. The precursor pulse time was 0.5 s, and the dwell time was set to 80 s.

Example 3

The atomic layer deposition process is the same as that of the embodiment (1), except that the process conditions are different: the number of membrane filaments hanging from the hollow fiber membrane (9) is 1000, and the modified outer surface area is 2m ² . Adjust the rotation speed of the motor to 60r/min, and the temperature of the cavity (1) to 80°C. The precursor pulse time was 0.1 s, and the dwell time was set to 100 s.

Claims (9)

1. A rotary atomic layer deposition reactor for batch modification of hollow fiber membranes, characterized in that it includes a cavity (1) and an upper cover (5), and the top of the cavity (1) and the upper cover (5) pass The sealing ring (4) is sealed and connected, and the bottom of the cavity (1) is provided with an air inlet pipe (10) and an air outlet pipe (11); the motor (6) with a magnet (3) is fixed on the top of the upper cover (5), and the motor (6) Drive the magnet (3) to rotate through the rotating shaft (7); there is the same magnet (3) in the cavity (1), under the interaction force of the magnets, the magnet (3) in the cavity (1) Rotates with the rotation of the motor (6); the bracket (8) is fixed on the side wall of the cavity (1), and the magnet (3) is fixed on the bracket (8) through the shaft (7); the end of the shaft (7) is connected to a porous The turntable (2), the hollow fiber membrane (9) is suspended on the porous turntable (2). 2. A rotary atomic layer deposition reactor for batch modification of hollow fiber membranes according to claim 1, characterized in that the holes in the porous turntable (2) are arranged in concentric circles, and the hollow fiber membranes ( 9) Hang on the porous turntable (2) through the raw material belt, and put it into the reaction chamber (1). 3 . The rotary atomic layer deposition reactor for batch modification of hollow fiber membranes according to claim 1 , wherein the sealing ring ( 4 ) is a fluorine rubber O-ring. 4 . 4. A rotary atomic layer deposition reactor for batch modification of hollow fiber membranes according to claim 1, characterized in that the bracket (8) is fixed on the side wall of the cavity (1) with screws. 5. A process for carrying out an atomic layer deposition reaction in a rotary atomic layer deposition reactor facing batch modification of hollow fiber membranes according to any one of claims 1-4, wherein the atomic deposition steps are as follows: Step 1. The chamber (1) is heated up to the atomic layer deposition reaction temperature, the motor (6) is turned on, and the rotation speed is adjusted; Step 2. Using high-purity nitrogen as the carrier gas, the precursor titanium tetrachloride is pulsed into the cavity (1) through the inlet pipe (10) and stayed for a period of time; the precursor gas is stirred under the rotation of the hollow fiber membrane (9) Uniformly dispersed in the cavity (1) and fully contacted with the hollow fiber membrane (9), a monomolecular layer chemical adsorption reaction occurs on the surface of the membrane, and then nitrogen gas is injected for 200s to purge the excess reactants and by-products, and the gas outlet pipe ( 11) discharge system; Step 3. Then continue to feed the precursor oxygen source H ₂ O, using high-purity nitrogen as the carrier gas, pulse H ₂ O into the cavity (1) through the inlet pipe (10) and stay for a period of time; monomolecular layer chemical reaction, and then blowing nitrogen gas for 200s to purge excess reactants and by-products, and discharge the system from the outlet pipe (11); after the completion of steps 2 and 3, it is a cyclic atomic layer deposition reaction; Step 4. After repeating the atomic layer deposition reaction for 50-200 cycles, remove the upper cover (5), and the screws connecting the support (8) and the cavity (1), and then place the porous hollow fiber membrane (9) The turntable (2) is taken out. 6. A process for performing atomic layer deposition reaction in a rotary atomic layer deposition reactor for batch modification of hollow fiber membranes according to claim 5, characterized in that the pulse of the precursor pulse entering the cavity (1) The time is 0.1-0.5s, and the residence time is 50-100s. 7. A process for performing atomic layer deposition reaction in a rotating atomic layer deposition reactor facing batch modification of hollow fiber membranes as claimed in claim 5, characterized in that the number of membrane filaments hanging the hollow fiber membranes (9) is 500-1000 pieces, the modified surface area is 1-2m ² . 8. A process for performing atomic layer deposition reaction in a rotary atomic layer deposition reactor for batch modification of hollow fiber membranes as claimed in claim 5, characterized in that the speed adjustment range of the motor (6) is 10-60 r /min. 9. A process for performing atomic layer deposition reaction in a rotating atomic layer deposition reactor for batch modification of hollow fiber membranes according to any one of claim 5, characterized in that the chamber (1) for performing atomic layer deposition reaction The temperature is 80-150°C.