TWI408161B - A preparation method of polymer membrane containing nano iron particles by thermal decomposition method - Google Patents

Abstract

This invention is to provide a preparation method of polymer membrane containing nano iron particles by thermal decomposition method. The casting solution was heated over the decomposition temperature of iron pentacarbonyl in N-methyl-2-pyrrolidnone solution and formed the solution with nano iron particle. The temperature was heated up to 130 DEG C and then the carbon mono oxide was completely removed until no CO was generated from the NMP solution. The suitable polysulfone were added into the NMP solution stirring overnight at room temperature. After the bubbles were completely removed from the casting solution, the dry method was used to prepare the nano particle contained membranes at room temperature.

Description

Preparation method of preparing nanometer metal particle composite film by thermal cracking method

The invention relates to a preparation method for preparing a nanometer-containing metal particle composite film by a thermal cracking method.

According to the rapid development of science and technology in recent years, the industry is booming, but there are also many industrial pollution problems. Organic waste liquid is one of the problems caused by the rapid development of industry. Because it has serious harm to human health and ecological environment, It needs to be regulated and handled. The separation, concentration and purification of chemical substances in organic waste liquid is one of the main processes of the chemical industry, and it is a very important link. In addition, with the rising awareness of environmental protection and the decreasing resources in recent years, the separation technology has received more and more attention. Therefore, the chemical industry's requirements for separation procedures continue to be positively developed in terms of ease of operation, energy conservation, improved separation quality, and reduction of chemical contamination, and the separation characteristics of the membrane separation process coincide with the above-mentioned development trend. The membrane separation process is not only widely used in the chemical industry. In recent years, various membrane separation procedures have been successfully applied in industrial processes, such as industrial wastewater treatment, seawater desalination, drinking water preparation, ultrafiltration, micro Filtration, reverse osmosis, concentration and purification of food and pharmaceutical products, hemodialysis, recovery of valuable substances, gas separation, separation of oil and gas, recovery of volatile organic compounds (VOCs), separation and purification of substances contained in food and water, drugs Research and development of release, purification of gas/liquid, enrichment and fractionation of liquid mixtures, preparation of ultrapure water required for the electronics industry, etc., showing that membrane separation technology is efficient, rapid and economical; The technology has broken through the bottleneck of the traditional separation technology, and the separation of azeotropes, isomers, heat sensitivity and similar boiling points has a tendency to develop.

Compared with other separation programs, the membrane separation program is characterized by simple operation, simple module, high separation efficiency, low separation cost, energy saving, small floor space, no secondary pollution, and good quality after treatment. And the ability to recover valuable substances, so it has a very high economic value. Since the membrane separation process has great potential and has been successfully applied in various industrial applications and products, various membrane separation procedures have been developed.

According to its operating principle and application range, thin films can be roughly divided into: microfiltration, ultrafiltration, reverse osmosis, dialysis/electrodialysis, gas permeation and infiltration. Pervaporation or the like can be applied to various separation procedures depending on the characteristics of separation by selecting an appropriate film. The film can be regarded as the barrier layer through the separation of the feed and the discharge end in the separation process, and the separation process belongs to the passive transport, and the driving force is mainly divided into the pressure gradient (ΔP) and the concentration gradient. (ΔC), potential gradient (ΔE), and temperature gradient (ΔT), the related actions are shown in the first figure.

The separation process of a film is defined as an interphase, which separates the barrier between the two phases and controls the rate of mass transfer within the two phases. Therefore, two or more specific types are specified. The substance, when passing through a membrane (Membrane), can cause a screening effect, or when the substance moves inside the film, through the interaction between the substance and the film molecule, different movement rates are generated, resulting in separation of the substance. . Generally, it can be used as a material for a film, and all have a common characteristic, that is, it is possible to restrict various chemicals through a film in a special manner to achieve a desired separation effect. Generally, the characteristics of the film material itself are used, such as hydrophilic or hydrophobic functional groups to control the mass transfer phenomenon between the two phases, the pore size on the structure of the film itself, the functional group type, and the two phases. The shape, size, affinity, etc. of different molecules are used to limit the passage of various chemicals through the film.

The film may be classified into natural or synthetic depending on the material; according to the structure, it may be classified into a dense film (Dense membrane), a porous film (Porous membrane), and a composite film (Composite membrane). The porous film can be further subdivided into a symmetric film (Symmetric membrane) and an asymmetric membrane (Asymmetric membrane). The dense film means that it is very dense from the surface to the inside of the film without any pore structure; the porous symmetric film means that the distribution of the pores and the pore size are very consistent from the surface to the inside of the film; The surface to the inside, the distribution of the pores and the pore size are very inconsistent, which is called a porous asymmetric membrane; as for the composite membrane, in addition to the positive substrate film (generally a porous asymmetric film), the upper layer is coated with a higher layer. Molecules to form a dense film.

Generally, the thickness of the symmetric film is between about 10-200 μm, and the resistance of the mass transfer is controlled by the thickness of the film, that is, the permeation flux decreases as the thickness of the film increases, but the selection ratio increases; although the separation effect is good, but To deal with the large amount of organic waste liquid produced by today's industry, it may be necessary to process all waste liquids in batches. Therefore, the current industrial applications have the high permeability of asymmetric membranes and the advantage of maintaining a certain selection ratio. And is focused on development and application. The asymmetric film combines the high selectivity of the dense membrane with the high permeation throughput of the ultra-thin membrane, and the structure consists of a skin layer having an upper thickness of about 0.1 to 1 μm and The sublayer consists of a porous sublayer having a thickness of about 50-150 μm. Another composite membrane is also a kind of asymmetric membrane. The dense cortex is different from the asymmetric support layer, and often uses dip-coating and interfacial polymerization. Or plasma polymerization method (plasma polymerization) and other methods, the porous support layer is coated with another different material polymer to form a dense layer, mostly for the mainstream application of modern industrial asymmetric film.

In the membrane separation process, the separation performance is determined depending on the nature of the membrane itself and the membrane structure. The membrane can be distinguished as a hydrophilic membrane and a hydrophobic membrane. Hydrophilic membranes usually have hydrogen bonds or polar-polar highs; such membranes have a strong affinity for water and are therefore widely used in dehydration processes. Common membranes have poly(vinyl). Alcohol), poly(acrylic acid), cellulose (cellulose), etc. Hydrophobic membranes are functional groups that do not have affinity for water or have less force with water and are repellent to water. Common membranes include poly(ethylene), poly(propylene), etc. .

The film structure can be distinguished as a porous film having a pore or a dense film, which itself swells in the film separation process; in addition, the film Its crystallinity, hydrophilicity or hydrophobicity may affect the results of the separation procedure, as well as the molecular structure, shape, size of the separated material itself and the interaction between the separation membranes. It is one of the factors affecting the separation effect, so it is possible to select a suitable film material for the characteristics of the material to be separated, and to form a suitable film by a suitable process.

The preparation method of the film includes a sintering method, a stretched method, a tracked-etched method, and a phase inversion method, and the phase conversion method is generally used. A commonly used film preparation method. The phase inversion method is a polymer film that converts a homogeneous liquid phase polymer solution into a solid phase. The phase conversion method can be divided into the following methods:

1. Thermal induced phase separation (TIPS): It is to reduce the solubility of homogeneous polymer solution by temperature change, control the generation of phase separation behavior, and promote the precipitation of polymer to form a gel ( Finally, a film is formed, and the remaining solvent is removed by extraction, evaporation, or freeze drying, and finally dried to form a film. Therefore, the heat-induced phase inversion method controls the temperature drop rate and temperature change after casting, and adjusts the phase separation behavior, thereby changing the film to form different structures.

2. Precipitation by solvent evaporation: a solution solution prepared by mixing a polymer with a volatile solvent, a homogeneous polymer solution at a fixed temperature, and gradually evaporating the solvent in a constant temperature program. After volatilization, after complete volatilization, since the solubility of the polymer solution is lowered, phase separation occurs to form a porous film structure.

3. Wet-phase inversion: The method is as follows: the polymer solution is cast into a film and then immersed in a coagulant (non-solvent). At this time, the solvent and the coagulant are diffusion-exchanged, and the non-solvent is used. The solvent added in the casting solution is extracted, and the coagulant can also enter the casting solution, resulting in a decrease in the solubility of the polymer and solidification of the casting solution into a film. The film thus obtained usually has a porous structure and the film structure has variability and adjustability; this method is commonly used to produce an asymmetric film.

4. Dry/Wet process: In simple terms, the dry phase conversion method and the wet phase conversion method are used together; the casting solution is allowed to volatilize the solvent at a fixed temperature after casting the film. Time, and then immersed in the coagulant to solidify the polymer into a film, wherein the solvent volatility and volatilization time are important factors affecting the formation of the dense layer of the film.

An excellent film has high separation efficiency and high selectivity. However, the two cannot usually be considered at the same time. When the amount of the film is large, the selection ratio is lowered. Conversely, when the selectivity is increased, it tends to Its permeability has decreased; in many previous studies, it has been pointed out that the hydrogen-bonding effect between the polymer film and the feed solution is critical to the selectivity of the film, so if it is made of only a single polymer material. The pervaporation separation membrane is difficult to completely combine the requirements of an excellent membrane such as high mechanical strength, high permeation flux (P) and high selectivity (α), but if two or two types can be combined The advantages of the above materials are modified to form a composite film, in order to achieve a breakthrough in film performance, a better separation effect can be achieved. The combination of two or more materials adopted in the conventionally known research is as follows:

1. Blending: The blending of polymers is done by physical means, and the relationship between the polymer and the polymer is improved by the mutual miscibility. The phenomenon of phase separation, usually by selecting an optimum value between the solubility parameters of the two polymers as a common solvent for the dipolymer, or mixing the advantages of the two polymers in an appropriate ratio to achieve better Transmission separation factor and mechanical strength. In order to achieve the purpose of upgrading, the most important thing to note is that the compatibility between the materials must be taken into consideration when blending the modified materials, because only the two polymers can achieve better penetration at the most appropriate mixing ratio. Rate, separation factor and mechanical strength. The disadvantage of the blending method is that the selected two polymers must have a certain compatibility, and must be blended in an appropriate ratio. The blended film usually has a permeability property between the original materials.

2. Chemical grafting: Graft polymerization is the most commonly used method to improve the physical and chemical properties of polymer materials. The initiator is used to initiate the polymerization reaction and the monomer is attached to the main chain of the polymer. Free radicals are formed, and one of these radicals is polymerized in a free radical state to polymerize, and the other end is activated by oxygen to form a peroxide. The advantage is that monomers with different characteristics can be grafted according to different requirements, but the biggest disadvantage is that it may be affected by variables such as initiator, temperature, concentration, degree of grafting, etc. during the grafting process, and Some residual waste liquid produced afterwards can cause pollution.

3. Plasma modification: The energy and activity of plasma are higher than the gaseous state of general materials. Generally, gas molecules are electrically neutral, but in strong energy and electric field, neutral molecules can be excited or dissociated into Active substances such as electrons, ions, and radicals are called plasma states. The use of plasma modification has the following advantages: forming a uniform pinhole-free ultra-thin film on the surface of the substrate, good adhesion to the substrate, chemical stability and physical durability of the formed material, and only changing the surface of the substrate Quality does not affect its overall nature.

The development of pervaporation in the past two decades has been successfully applied to the separation process of various chemical industries. The pervaporation process is often applied to the separation and purification of liquid mixtures, especially for the production of ultra-high purity organic solvents. It is more dominant, so it is advantageous for separating organic solvents such as ethanol, iso-propanol, and ethylene glycol. There are many commercial pervaporation procedures for commercial operation and pervaporation. It combines two different procedures of permeation and vaporization. The penetrating medium of pervaporation follows the solution-diffusion mode, that is, the solution dissolves into the film and the components in the solution are distributed. Compared with the dissolution and swelling of the surface film, different concentration gradients are formed according to the difference of the distribution ratio, and the components in the solution continuously diffuse to the non-swelling layer of the film, and the components in the solution diffuse to the downstream surface of the film for desorption, as shown in the second figure. The solute passes through the membrane through the process of pervaporation, usually because the downstream is in a low pressure state. Once the components in the solution diffuse into the membrane, the solute is usually easily converted from the liquid phase to the gas phase during the diffusion process, and the swelling degree of the film is rapidly reduced. However, the phenomenon of increased resistance occurs. Therefore, the longer the mass transfer process, the smaller the solute permeability of the film is, and the medium is desorbed away from the film when the penetrating medium reaches the downstream surface of the film. This desorption step occurs rapidly and its desorption process is only related to downstream pressure. From the above analysis, it is known that the mass transfer behavior of the penetrating medium in the film is determined by two factors:

1. The magnitude of the activity gradient of the penetrating medium in the non-smooth layer of the film. Generally, the size of the active gradient depends on the concentration of the surface layer of the film dissolved in the penetrating medium. Generally, the penetrating substance which is more soluble in the surface layer of the film is easier to establish a higher concentration gradient. The gradient can be plasticized and solvent. The effect of the coupling effect is reached to achieve the establishment of a higher concentration gradient. In the case of a general polymer film, the penetrating medium which is more soluble in the film is also faster in the film, so most of the pervaporation separation membranes are selected to have similar solubility to the medium to be penetrated.

2. The difference in the diffusion behavior of the solution components in the non-swelling layer of the film and the diffusion behavior of the solution components in the film are determined by the relative size of the penetrating molecules and the pores of the film and the strength of the interaction between the penetrating molecules and the functional groups of the film polymer. If the interaction between the penetrating molecule and the film is significant, the diffusion behavior of the penetrating molecule is less affected by the relative size of the penetrating molecule and the film, and the intermolecular force determines the mass transfer resistance of the penetrating medium.

The separation efficiency of the membrane plays an important role in various separation procedures. The separation efficiency mainly refers to the amount of permeation and the selectivity to each species to be separated. A good film must have the conditions of superior separation performance, that is, high transmission and excellent selectivity, but the two can not always take care of both. In general, a membrane with a large amount of permeation will have a lower selectivity; conversely, when the selectivity is increased, the amount of permeation will tend to decrease. So there are many ways to develop it that can overcome this problem. For example, chemical grafting and radiation grafting can successfully modify the film, but the grafted layer cannot have a completely uniform grafting degree or a completely defect-free synthetic film; and can be successfully prepared by blending and coating techniques. A defect-free synthetic film is produced, but the biggest drawback of the blending technique is that it is necessary to find out the solubility of the polymer to be blended; due to the various modifications described above, it is impossible to prepare a thin and defect-free synthetic film. .

Therefore, it is urgent to find a better preparation method to prepare an asymmetric film with good pervaporation separation efficiency. In view of these needs, the inventors have intensively studied the invention, and the invention has been completed.

The main purpose of the present invention is to provide a preparation method for preparing a nano-particle-containing composite film by thermal cracking to achieve a good pervaporation separation efficiency.

In order to achieve the above object, the present invention develops a preparation method for preparing a nanometer-containing metal particle composite film by a thermal cracking method, and firstly, a casting solution solution is prepared by a thermal cracking method, and the process is to extract iron pentacarbonyl (Fe (I). CO) ₅ ) The solution is added to the solvent of N-methyl-2-pyrrolidnone (NMP) to prepare a solution of iron pentacarbonyl, placed in a heating stirred tank, and heated at 130 ° C. At least 30 minutes, the CO gas is removed, and the nano metal iron solution is completed; then the polysulfone (PSF) polymer particles are dissolved in the above nano iron solution, thoroughly dissolved at room temperature, and then left to stand still. The bubble in the casting solution is completely removed, that is, the configuration of the casting solution is completed; then, the composite film containing the nano metal particles is prepared by the dry phase conversion method using the above casting solution.

In the above invention, the nano-particle-containing composite film prepared by the nano metal iron concentration of 4% by weight has the best pervaporation separation index (PSI).

In order to achieve the above objects, the technical means and the effects achieved, the following preferred embodiments are described in detail with reference to the accompanying drawings, which are fully understood.

In the embodiment of the invention, the casting solution is firstly prepared by a thermal cracking method, and the process is to extract the solution of iron pentacarbonyl (Fe(CO) ₅ ) into N-methyl-2-pyrrolidnone. , NMP) solvent, prepared into different concentrations of the five iron carbonyl solution, and then placed in a heating and agitation tank, heated at 130 ° C for 30min, remove CO gas, complete the nano-iron solution. Then, the polysulfone (PSF) polymer particles were dissolved in the above-mentioned nano-iron solution, placed in a 50 mL serum bottle, thoroughly stirred at room temperature for 24 hours in a magnetic stirrer, and then completely dissolved. The bubbles in the membrane solution are completely removed, that is, the configuration of the casting solution is completed. Then, in the embodiment of the present invention, the nanometer metal particle composite film is further prepared by using the above casting solution, and the process is prepared by a dry phase conversion method. Before the film is scraped, the flat glass is washed and rinsed with deionized water. After drying, the clarified casting solution solution that has been left to stand is placed on a glass plate, and a uniform layer and a different thickness on the support (glass) is applied by a doctor blade, and then placed in an oven (85 ° C) to evaporate the solvent in the film. The film was solidified into a film, and the film was dried in a vacuum oven at room temperature for 24 hours to complete the preparation process of the nano-particle-containing composite film.

In the embodiment of the present invention, after preparing the nanometer-containing metal particle composite film by thermal cracking method, the influence of the nanoparticle-containing composite film prepared by the thermal cracking method on the pervaporation performance is further investigated, and Rice metal particle composite film for swelling, adsorption, environmental scanning electron microscope / X-ray energy dispersion analyzer (E-SEM / EDS), total reflection type Holstein conversion infrared spectrometer (ATR-FTIR), contact angle (Contact angle ) Analysis and discussion of film structure and affinity for water.

The present invention uses different concentrations of pentacarbonyl iron (2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt% Fe(CO) ₅ /PSF), and 25 mL of N-methyl 2-tetrapyrrolidone (N- Methyl-2-pyrrolidnone, NMP) mixed, and heated to 130 ° C for constant temperature stirring for 30 min, after cooling to complete the solution containing nano metal iron particles, and then add 7.5 g of polyfluorene (PSF) polymer particles to the nano iron In the solution, a 23 wt% polymer cast film solution was prepared, and after mixing and stirring, a dense nano-particle composite film was prepared.

The addition of nano-iron particles to the polymer solution will affect the interaction between the molecular chains. As shown in the third figure, as the concentration of different nano-iron increases, the separation effect of the film is significantly improved. When the concentration of nano-iron is 4wt% The highest permeation selectivity is obtained. Then, as the concentration of nano-iron increases, the selectivity through gradual decrease, but there is no significant change in the permeability of nano-iron particles. The main reason is the addition of nano-iron to the polymer. In the solution, the nano-iron particles generate the attraction between the molecular chains to make the polymer structure more compact, and the narrow gap between the polymer and the polymer after the film formation is reduced, so that the composite film is denser and the separation effect is enhanced. However, the addition of too much nano-iron will form agglomeration, which causes the nano-iron particles to form an immiscible phenomenon in the polymer solution. When the polymer solution is formed into a film, cracks on the surface structure of the composite film may occur. Reduce film separation performance. It can be seen from the third figure that the nano-iron film (0wt%) without the addition of a selectivity of 603, but when the composite film of 4wt% nano-iron is added, the separation performance is 1728, and the performance is improved. About 3 times.

The fourth picture is an environmental scanning electron microscope (SEM) surface map containing 100,000 times different compositions of nano-iron particle film. It can be seen from the figure that as the nano-iron content increases, the polymer arrangement structure is more compact, but too much The nano iron makes the surface crack, which reduces the separation effect.

The fifth figure shows the Pervaporation Separation Index (PSI) value of the nano-iron concentration of 0 wt% to 10 wt%. The separation effect of the pervaporation film depends on the medium permeation rate and the selectivity (Separation). Factor), so compare the membrane pervaporation performance, often with the Pervaporation Separation Index (PSI) as a reference, and PSI = medium permeability P (g / m ² h) × separation coefficient (α), can be found when the nano The pervaporation nanocomposite film prepared at an iron concentration of 4% by weight has the best pervaporation separation index (PSI). It is known from the results that the composite film prepared by adding 4wt% nano iron has the best mechanical properties and high pervaporation separation index, and the overall PSI value is more than 20,000, which is sufficient for commercial PV operation. .

In the embodiment of the invention, the nanometer-containing metal particle composite film prepared by the thermal cracking method is immersed in a temperature of 25 ° C, 90 wt% ethanol solution for 24 hours, so that the film fully absorbs the ethanol/water solution, and then the film absorbs the solution content, and The degree of swelling of the composite film in the solution was calculated. The sixth figure shows the swelling degree of the nanocomposite film prepared by adding different concentrations of nano-iron, wherein the nano-metal iron film does not have a swelling degree of 10%, and the nano-metal composite film is added with different proportions of concentration. The swelling degree is close to 8%, and there is no obvious change due to the excessive iron content added. It can be seen that after the addition of iron metal particles, the degree of swelling is significantly reduced by 2%, but the amount of nano-iron does not significantly affect the degree of swelling. The main reason is the addition of nano-metal particles to the polymer solution. Nano-iron produces a molecular chain effect, which makes the polymer structure more compact and solid, resulting in the film not being easily swelled. The relative permeability will not change much, and there will be a higher choice. Sex. From the results of the third graph, the behavior of the film permeation amount is in accordance with the swelling measurement, but the selectivity is gradually decreased when the selectivity is high in the concentration of nano-iron, but there is a spectacle of the decrease in the degree of swelling. Therefore, in order to understand the adsorption and desorption behavior of ethanol/water on nanocomposite film, the nano-composite dense film with different nano-iron content was subjected to adsorption experiments to understand the effect of different nano-iron content on adsorption behavior. To explain the reasons for its selective decline.

In the embodiment of the present invention, the nanometer-containing metal particle composite film prepared by the thermal cracking method is subjected to adsorption test by using a 90 wt% ethanol solution, and if the amount of ethanol adsorbed by the film is more than 90% by weight, the composite film pair is Ethanol has a higher affinity; if more water is adsorbed, it means that the composite film is more hydrophilic. As shown in the seventh figure, as the content of nano-iron increases, the composition of water molecules adsorbed by the film increases, which is due to the affinity between the metal iron and the water molecules. The nano-metal iron makes the polymer piled tighter and is not easy to swell, so the ethanol molecules cannot enter the structure from the polymer gap. Therefore, the nano-metal iron composite film is advantageous for the adsorption composition, and the water molecules are more favorable than the ethanol molecules. The adsorption selectivity of the composite film also increases as the amount of nano-iron increases.

The eighth figure shows the adsorption selectivity of the nano metal particle composite film prepared by adding different concentrations of nano metal iron. As the concentration of nano metal iron increases, the adsorption selectivity ratio increases, mainly due to the nano metal particles. The composite film has a higher affinity with water molecules, so that the adsorption selectivity ratio of the nano metal iron content increases. The ninth graph shows the diffusion selectivity ratio. It can be seen from the graph that the diffusion selectivity has a tendency to rise first and then decrease with the increase of the iron content of the nano metal. The highest diffusion selectivity ratio is obtained when the iron content of the nano metal is 4 wt%. The main reason is that when the iron content of nano metal is increased, the nano metal iron is more hydrophilic, but the excessive nano metal iron tends to cause the polymer gap to increase, causing the ethanol molecules to penetrate into the film and reduce the diffusion selectivity. .

The embodiment of the invention further proves that the hydrogen bond gravitational force between the penetrating medium and the film in the nano metal particle composite film affects the pervaporation separation in the ethanol/water environment, so the nano metal particles impregnated with ethanol and water are compounded. The film was analyzed by infrared spectrometer, and the displacement of the absorption wave number caused by the hydrogen bonding force of the OH functional gene was compared to determine the affinity characteristics of the nano metal particle composite film and ethanol/water. Since the film contains an aqueous solution of ethanol, there may be five kinds of OH functional groups in the swelling solution, namely OH of free water, OH of free ethanol, OH of membrane-water, OH of membrane-ethanol, and H bond of ethanol and water. OH. Because the OH functional group and the ethanol-water form intermolecular hydrogen bond, the absorption position of the original nano metal particle composite film must be shifted, so the infrared spectral shift of the OH functional group can be used as the nano metal iron composite film to the water. Or a description of the force of ethanol. Since the OH function of the ethanol molecule has a broad absorption peak based on 3400 cm ^-1 , the hydrogen bond index is calculated by dividing the absorption intensity of the OH functional group of 3600 cm ^-1 by the absorption of the CH bond on the carbon chain, and the OH functional group. If the absorption intensity is stronger, a larger hydrogen bond index is formed, so that the penetrating medium is in a strong action state. Another indicator of the strength of the force is the amount of OH absorption wave number shift. When the water or ethanol force is strong, the displacement to the low wave number is larger. Therefore, comparing the displacement wave number can also prove that the hydrophilic or pro The strength of ethanol. From the tenth figure, the magnitude of the offset between ethanol and water and the composite film can be compared. As the iron content of the nano metal increases, the hydrogen bonding force is stronger and the hydrogen bond index is larger, so it can be known in the nanometer. The hydrophilicity of the metal-iron composite film will increase with the number of nano-metal iron content, and the stronger the hydrogen bonding ability, the stronger the hydration ability.

Next, in order to understand the effect of different ethanol feed concentrations on the pervaporation of the nano-metal iron composite film, the separation performance of pervaporation was tested at a feed ethanol concentration of 70 wt%, and the results were as shown in Fig. 11 when the ethanol concentration was When the concentration is 70wt%, with the increase of iron concentration of different nano metals, the highest separation efficiency is obtained when the iron content of nano metal is 4wt%, and then the separation efficiency decreases with the increase of the concentration of iron metal in the nano metal. There is no significant change in the amount of transmission, and a certain amount of transmission is maintained. The reason is that nano-metal iron will make the polymer structure more compact, making the nano-metal particle composite film not easy to swell, so its permeation amount is almost maintained at about 300 (g/m ² hr), but its separation effect is limited. The phenomenon of agglomeration of nano-metal iron makes the high-concentration nano-metal iron content unable to effectively exert its nano-effect, and because of the large metal particles, it is easy to form pores, resulting in a decrease in separation effect.

Continuing, in order to investigate the effect of low feed concentration on the nano-metal composite film, the ethanol content was reduced to 50% by weight to test the separation performance of pervaporation. It can be seen from the twelfth figure that when the ethanol concentration is reduced to 50 wt% At the same time, with the increase of the concentration of different nano-metal iron, the separation effect is the highest separation efficiency when the nano-iron content is 4wt%, and then the separation efficiency decreases with the increase of the nano-metal iron concentration. There is no significant change in the amount of transmission, and a certain amount of transmission is maintained. The reason is that nano metal iron builds up the polymer structure more tightly, and the nano metal iron composite film is less likely to swell due to lowering the concentration of ethanol, so the permeation amount is maintained at about 300 (g/m ² hr), but The separation effect is the same as that of the above-mentioned higher feed concentration. As the concentration of nano-metal iron increases, the separation effect decreases, but the extent of the decrease is significantly slower than the aforementioned high ethanol concentration.

The embodiment of the present invention further reduces the ethanol feed concentration to 30% by weight. As a result, as shown in the thirteenth embodiment, it can be seen that the nano metal particle composite film prepared by the embodiment of the present invention has an ethanol concentration of 30% by weight. The effect of pervaporation separation is better when the content of nano-iron is 4wt%, but there is no significant difference between the separation effect of other nano-iron concentrations. The main reason is the decrease of ethanol content and the swelling effect of ethanol. Molecules are not easy to penetrate, so the difference in separation efficiency is brought closer, and the amount of permeation does not change significantly. It is almost the same as the above-mentioned higher feed concentration, and is almost at around 300 (g/m ² hr).

In the embodiment of the present invention, the ethanol feed concentration is finally lowered to 10 wt%, and the result is as shown in Fig. 14, it can be clearly seen that when the ethanol feed concentration is reduced to 10 wt%, the separation effect has no obvious change. The separation performance of different nano-iron concentrations is almost the same. The main reason is that when the ethanol concentration is very low, the composite film cannot be effectively swollen, which causes the agglomeration phenomenon due to the excessive iron content of the nano-ene, resulting in a decrease in selectivity. The factors have no obvious influence, and because the nano-iron composite film has low swelling property, the amount of permeation is maintained at a certain amount regardless of the change in the feed concentration, and there is no excessive fluctuation.

Next, in order to understand the effect of the nano metal iron composite film on the pervaporation at different feed temperatures, the experiment was carried out at a feed temperature of 15 ° C. The results are shown in Fig. 15 and the nano iron content is still At 4wt%, there is the best separation performance, and then it gradually decreases. Compared with the results of the above third chart (at a feed temperature of 25 ° C), it can be clearly observed that the separation effect at 15 ° C is much higher than that at 25 ° C. From this, it is understood that the high concentration of ethanol swells the gap between the polymers, but is suppressed at a low temperature, so that the separation effect is enhanced. However, although the low temperature slightly suppresses the distance between the polymer slits, it does not affect the amount of permeation, and the same is maintained at about 290 to 300 (g/m ² hr), and there is no significant change.

Next, the experiment was carried out at a feed temperature of 35 ° C. The results are shown in Fig. 16. It is known that increasing the feed temperature has a slight influence on the separation performance of the prepared composite film, although the separation efficiency is still in the nano iron content. 4 wt% is the best, but there is a slight decrease in the separation effect relative to the lower feed temperature (15 ° C and 25 ° C). The reason is that the temperature rise causes the gap between the polymers to increase, so that the ethanol molecules are more likely to diffuse into the film, resulting in a lower selectivity, and the hydration force decreases with increasing temperature. The force, therefore, reduces the separation effect of ethanol/water, but because the accumulation between the polymers is very close, the amount of transmission still does not change much.

In order to further determine the influence of the feed temperature on the pervaporation of the nano-metal iron composite film, the temperature is raised to 45 ° C, and the result is as shown in Fig. 17, when the feed temperature is raised to 45 ° C, The selectivity is significantly reduced, and the separation efficiency of different nano-iron contents is greatly different from the lower feed temperature. It can be seen that the temperature of 35 ° C is the critical point of the nano metal iron composite film of the present invention; as the temperature increases, the nano metal iron composite film cannot withstand the swelling caused by high temperature, and the hydration is very low. The selection ratio decreases as the temperature increases, but the amount of permeation does not appear to be affected by the high temperature, and is maintained at 300 (g/m ² hr). Therefore, the high temperature increases the distance between the polymers, but decreases the selectivity, but does not affect the amount of permeation.

The invention provides a nanometer-containing metal particle composite film by thermal cracking method and a preparation method thereof, and the following conclusions can be obtained through the above experiments:

1. The composite film containing nano metal particles prepared by pyrolysis method, with the increase of the concentration of nano metal iron, the separation effect of the film is obviously improved, and the highest transmission selectivity is obtained at 4wt%; As the concentration increases, the permeation selectivity decreases gradually, but the amount of permeation does not change significantly.

2. Excessive nano-metal iron tends to form agglomeration, which causes the formation of immiscible phenomenon of nano-metal iron particles in the polymer solution. When the polymer solution is formed into a film, cracks appear on the surface structure of the composite film. The film separation performance is lowered.

Third, the molecular chain force effect produced by nano metal iron makes the polymer structure more compact and solid, so that the film is not easily swelled, and the relative transmittance does not change much, and there is Higher selectivity.

Fourth, the nano metal iron and water molecules have a more affinity, and the nano metal iron makes the polymer accumulation more compact, not easy to swell, so the ethanol molecules can not enter the structure from the polymer gap, compared to the water molecules It is more advantageous than ethanol molecules, and the adsorption selectivity of the composite film also increases as the content of nano metal iron increases.

5. The increase of the iron content of the nano metal, the stronger the hydrogen bonding force and the larger the hydrogen bond index. It can be seen that the hydrophilicity of the nano metal iron composite film increases with the content of the nano metal iron. The stronger the hydrogen bonding ability, the stronger the hydration ability.

It can be seen from the above description that the preparation method of the nanometer-containing metal particle composite film is prepared by the thermal cracking method, and the main technical content is that the casting solution is firstly prepared by a thermal cracking method, and the process is to extract iron pentacarbonyl (Fe (I). CO) ₅ ) The solution is added to the solvent of N-methyl-2-pyrrolidnone (NMP) to prepare a solution of iron pentacarbonyl, placed in a heating stirred tank, and heated at 130 ° C. At least 30 minutes, the CO gas is removed, and the nano metal iron solution is completed; then the polysulfone (PSF) polymer particles are dissolved in the above nano iron solution, thoroughly dissolved at room temperature, and then left to stand still. The bubble in the casting solution is completely removed, that is, the configuration of the casting solution is completed; then, the composite film containing the nano metal particles is prepared by the dry phase conversion method using the above casting solution; wherein, when the concentration of the nano metal iron is 4 wt% The prepared nano-particle-containing composite film has the best pervaporation separation index (PSI).

In summary, the present invention is indeed a preparation method that has never been seen before. After many experiments and tests, it is proved that the effect is good, and the industrial use value is deeply used, and the invention patent application is filed. I would like to ask for a patent as soon as possible after the review.

The first figure is a schematic diagram of the related functions of the conventional film.

The second figure is a schematic diagram of the conventional method for pervaporation of a film.

The third graph is the relationship between the effect of adding different nano iron concentrations in the present invention on 90% by weight of ethanol at 25 ° C on pervaporation.

The fourth figure is an environmental scanning electron microscope (SEM) plan for adding different nano iron concentrations in the present invention.

The fifth figure is the relationship between the pervaporation separation index (PSI) value of the present invention adding different nano iron concentrations at 90 wt% ethanol at 25 ° C.

The sixth figure is a graph showing the relationship between the swelling degree of different nano iron concentrations added by the present invention.

The seventh figure is an ethanol/water relationship diagram of adding different nano iron concentrations in the present invention.

The eighth figure is a graph showing the adsorption selectivity ratio of different nano iron concentrations in the present invention.

The ninth graph is a graph showing the diffusion selectivity ratio of different nano iron concentrations in the present invention.

The tenth figure is an IR spectrum of the invention adding different nano iron concentrations

The eleventh figure shows the effect of adding different nano iron concentrations in the present invention on the pervaporation of 70 wt% ethanol at 25 ° C.

The twelfth figure is the relationship between the effect of adding different nano iron concentrations in the present invention on 50% by weight of ethanol at 25 ° C on pervaporation

The thirteenth figure is a diagram showing the effect of adding different nano iron concentrations in the present invention on the pervaporation of 30 wt% ethanol at 25 ° C.

Figure 14 is a diagram showing the effect of adding different nano iron concentrations in the present invention on the pervaporation of 10 wt% ethanol at 25 ° C.

The fifteenth figure is the relationship between the effect of adding different nano iron concentrations in the invention on 90% by weight of ethanol at 15 ° C on pervaporation

Figure 16 is a diagram showing the effect of adding different nano iron concentrations in the present invention on the pervaporation of 90 wt% ethanol at 35 ° C.

Figure 17 is a diagram showing the effect of adding different nano iron concentrations in the present invention on the pervaporation of 90 wt% ethanol at 45 ° C.

Claims (1)

A preparation method for preparing a nanometer-containing metal particle composite film by thermal cracking method, wherein a casting solution solution is mainly prepared by a thermal cracking method, wherein an iron pentacarbonyl (Fe(CO) ₅ ) solution is added to the N-A solution. In the solvent of N-methyl-2-pyrrolidnone (NMP), it is prepared into a solution of iron pentacarbonyl, placed in a heating and stirring tank, and heated and stirred at 130 ° C for at least 30 minutes to remove CO gas. a concentration of 4 wt% of nano metal iron solution; followed by weighing polysulfone (PSF) polymer particles dissolved in the above nano iron solution, fully stirred at room temperature, completely dissolved, and then left to be cast The bubble in the solution is completely removed, that is, the configuration of the casting solution is completed; then, the composite film containing the nano metal particles is prepared by the dry phase conversion method using the above casting solution.