A Marangoni hydrogel reactor with high mass transfer efficiency, its preparation method and application

Abstract

This invention discloses a highly efficient mass transfer Marangoni hydrogel reactor, its preparation method, and its applications, belonging to the field of reactors. The reactor is a fuel-loaded cellulose hydrogel rotor capable of generating the Marangoni effect. The cellulose hydrogel rotor includes a front end and a rear end; the front end is a cross-linked cellulose hydrogel, and the rear end is a cellulose hydrogel loaded with catalyst noble metal nanoparticles. This invention employs a simple dual-mold method to construct an asymmetric polymer network by hydrogen bonding between two cellulose hydrogels with different pore sizes. The resulting significant gradient surface tension allows the prepared Marangoni hydrogel reactor to rotate at high speed and for extended periods at the water-air interface. It can be applied to the degradation of organic pollutants, improving the mass transfer efficiency of the degradation catalytic reaction and thus significantly enhancing the degradation catalytic effect.

Description

Technical Field

[0001] This invention relates to the field of reactors, specifically to a Marangoni hydrogel reactor with high mass transfer efficiency, its preparation method, and its application. Background Technology

[0002] With rapid economic development, organic pollutants in wastewater from various industries have seriously threatened the ecological environment and even human health. Wastewater discharge has attracted widespread attention from researchers. In recent years, nanomaterials, especially noble metal nanoparticles, have been widely used for the degradation of toxic organic pollutants and water remediation due to their unique physicochemical properties, such as high catalytic performance, good selectivity, and stability. Because noble metal nanoparticles are prone to aggregation and difficult to recycle, they are often loaded onto various supports for catalytic reactions. For example, many inorganic and organic porous materials have been selected as supports for noble metal nanoparticles. Among them, some natural polymers such as cellulose and lignin can serve as both supports for noble metal nanoparticles and reducing agents.

[0003] Loading noble metal nanoparticles onto cellulose-based hydrogels can yield highly efficient and stable reactors. However, in practical applications, this loading also presents challenges to catalysis: the substrate in the reaction needs to penetrate the porous structure and liquid film on the support surface to reach the catalyst surface. Unfortunately, due to the lack of driving force, the transport of substances in ordinary reaction systems relies entirely on the concentration gradient, resulting in slow substrate diffusion and low reaction rates. Therefore, hydrogel reactors prepared by existing methods are insufficient to maintain high mass transfer efficiency during catalysis. Developing more ideal and efficient mass transfer reactors for the biotransformation of noble metal nanoparticles has become an urgent problem to be solved in this field.

[0004] In recent years, to improve reaction rates, several methods for accelerating fluid motion have been proposed, such as stirred reactors, continuous fluid catalysis, and interfacial self-propelled robots, which effectively enhance mass transfer during the reaction process. For example, Chinese invention application No. 202211616988.5 discloses a heterogeneous substrate enzyme catalytic reaction device and method with high-efficiency mass transfer. This method uses a two-phase counter-current feeding mixing method in a tower reactor with internal components; however, the product yield of the catalytic reaction in this reactor is only 56.1%. Another example is Chinese invention application No. 202410431144.6, which discloses a continuous fluid method for the large-scale preparation of noble metal single-atom catalysts. This method involves transporting a nitrogen-containing carbon-based support dispersion and a noble metal salt solution to a reactor at a certain flow rate in the same direction under the drive of a peristaltic pump, mixing them uniformly, and reacting, which can effectively improve the contact efficiency between the two. However, this method requires additional equipment, such as mixers, pumps, and closed-loop liquid lines, making it complex and costly to operate. Therefore, there is an urgent need to develop a simple and efficient method to effectively improve catalytic efficiency by promoting mass transfer between catalyst and substrate without relying on complex equipment.

[0005] Meanwhile, self-propelled interface robots have broad application prospects in environmental monitoring, water treatment, and liquid pumping. In recent years, inspired by insects, researchers have developed a series of Marangoni self-propelled interface robots driven by surface tension gradients. However, existing Marangoni reactors cannot achieve a simple preparation method combined with strong dynamics and long-term motion. For example, Chinese invention application number 202111125634.6 discloses the preparation and application of a photoresponsive actuator based on the Marangoni effect. This actuator is mainly composed of a thin film made of polydimethylsilane, carbon, and iron oxide. Under illumination, the actuator only moves 150 mm within 90 seconds. Another example is Chinese invention application number 202211447338.2, which discloses a graphene soft robot capable of free movement on water and its preparation method. The soft robot is made by mechanically cutting a hydrophobic graphene film. The graphene film is prepared by simultaneously reducing, cross-linking, and hydrophobically modifying graphene oxide at high temperature using silane vapor. This preparation method is cumbersome, and the robot's movement efficiency is low, requiring additional energy for propulsion. Therefore, a simple preparation method, sufficient power, and long-lasting movement are key technologies that need to be addressed for reactors based on the Marangoni effect. Summary of the Invention

[0006] Objectives of the invention: The first objective of this invention is to provide a Marangoni hydrogel reactor with high efficiency in mass transfer; the second objective of this invention is to provide a method for preparing the above-mentioned reactor; and the third objective of this invention is to provide applications of the above-mentioned reactor.

[0007] Technical solution: The Marangoni hydrogel reactor with high efficiency mass transfer provided by the present invention is a cellulose hydrogel rotor loaded with fuel that can generate the Marangoni effect. The cellulose hydrogel rotor includes a front end and a rear end. The front end is a cross-linked cellulose hydrogel and the rear end is a cellulose hydrogel loaded with catalyst noble metal nanoparticles.

[0008] Furthermore, the fuel is isopropanol, n-propanol, hexafluoroisopropanol, ethanol, dimethyl sulfoxide, or acetone.

[0009] Furthermore, the precious metal is palladium, silver, or platinum.

[0010] The preparation method of the above-mentioned Marangoni hydrogel reactor includes the following steps:

[0011] (1) The cellulose solution and the noble metal salt solution are mixed, stirred and reduced to obtain a cellulose mixed solution loaded with noble metal nanoparticles. Then the above mixed solution is injected into mold 1 that can produce the Marangoni effect. After gelation, the mold is demolded to obtain the rear end of the cellulose hydrogel rotor.

[0012] (2) The rear end of the cellulose hydrogel rotor is placed into the mold 2 that can produce the Marangoni effect. Then, the cross-linked cellulose solution is injected into the empty part of the mold 2. After gelation, it is soaked in water to obtain the Marangoni cellulose hydrogel rotor.

[0013] (3) Immerse the Marangoni hydrogel rotor in fuel to obtain a Marangoni cellulose hydrogel rotor loaded with fuel, which is a Marangoni hydrogel reactor with high-efficiency mass transfer.

[0014] Further, in step (1), the method for preparing the cellulose solution is as follows: cellulose is dissolved in a mixed aqueous solution of sodium hydroxide and urea, and then homogenized to uniformly disperse the cellulose to obtain a cellulose solution; the mass percentage of cellulose in the cellulose solution is 1-3 wt%; the noble metal salt is palladium chloride, silver nitrate and chloroplatinic acid; the molar concentration of the noble metal salt in the mixed solution is 2.4-20.5 mmol / L.

[0015] Further, in steps (1)-(2), both the mold 1 that generates the Marangoni effect and the mold 2 that generates the Marangoni effect are gear-shaped structures, including a gear ring and several gear teeth. The gear teeth are located on the outer edge of the gear ring, which is a disc-shaped structure. The cross-section of the gear teeth of the mold 1 is a triangular structure with a vertex angle of 20-30°. The length of the side of the gear teeth near the gear ring is equal to the radius of the gear ring. The cross-section of the gear teeth of the mold 2 is an irregular triangular structure with an arc-shaped outer edge. The thickness of the gear ring is 2-4 mm, and the radius of the gear ring is 5-6 mm.

[0016] In a further preferred embodiment, in molds 1 and 2, the thickness of the gear ring is 2mm, the radius of the gear ring is 5mm, the length of the tooth on the side closest to the gear ring is 5mm, the apex angle of mold 1 is 25 degrees, and the outer side of mold 2 is a spline curve.

[0017] Further, in step (2), the method for preparing the cross-linked cellulose solution is as follows: epichlorohydrin is added to the cellulose solution and stirred thoroughly to obtain the cross-linked cellulose solution; wherein, the mass of epichlorohydrin is 2-5 wt% of the mass of the cellulose solution.

[0018] Furthermore, in step (3), the soaking time is 15-60 minutes.

[0019] The above-mentioned Marangoni hydrogel reactor is used in the degradation of organic pollutants.

[0020] Furthermore, the application method is as follows: the Marangoni hydrogel reactor is placed in a solution containing organic pollutants, and the Marangoni hydrogel reactor carries out a catalytic degradation reaction at the air-water interface through self-rotation; the molar concentration of the organic pollutant is 10 mmol / L-50 mmol / L; the organic pollutant is a dye.

[0021] Invention Principle: In this invention, when cellulose changes from a sol state to a solid hydrogel, hydrogen bonds reform between cellulose molecules. However, Pd 2+ The reduction process leads to the reduction of -OH groups, reducing the formation of hydrogen bonds in the cellulose chains and resulting in a loose microstructure. In contrast, during the chemical cross-linking process of the front-end hydrogel, the -OH groups on the cellulose chains are converted into C=O and COC, forming a highly cross-linked three-dimensional porous network. The asymmetric polymer network of the rotor constructed in this way generates a significant gradient surface tension during fuel release, thus generating sufficient power to achieve its high-speed spin. When the rotor is driven by the Marangoni effect, the rotating rotor promotes fluid disturbance and substrate movement. The rotor's rotational speed is higher than the substrate's movement speed. At the same time, the opposite direction of motion between the noble metal loaded on the rotor and the substrate promotes active contact between the two. In this case, the substrate will pass through the reactor pores to reach the catalyst surface more quickly, effectively improving mass transfer efficiency. Simultaneously, the fluid disturbance driven by the rotor causes relatively distant substrate homogenization. When the substrate around the rotor is consumed, the substrate at a distance will accumulate more quickly around the catalyst, increasing the concentration gradient around the rotor, significantly accelerating mass transfer, and thus improving the catalytic rate.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) In the reactor, cellulose forms a loose and a dense network through reduction and cross-linking, thereby forming different structures of internal and external hydrogels, which can generate significant gradient surface tension when the fuel is released; MCR can achieve high speed and long time rotation (up to 7200 r / h, rotation time greater than 25 min), indicating that the reactor has sufficient and lasting power; (2) Experimental results show that the material movement generated by rotation can accelerate the substrate into the reactor pores, while fluid disturbance can promote the replenishment of distant substrates around the catalyst, thereby improving the contact efficiency between the catalyst and the substrate and significantly improving the catalytic efficiency; kinetic results show that the kinetic constant of the Marangoni hydrogel rotor during rotation is 16.5 times that of the static porous hydrogel; based on this characteristic, the rotor can rapidly decolorize MB and MO within 2.3 min and 3.9 min; the degradation rate of dyes is as high as 99%. In addition, after repeated recycling, the degradation rate of the dye to MB is still above 85%; (3) Due to its good hydrophilicity, adding 80 μL of fuel in situ can extend the rotor rotation time by 13 min; (4) The preparation method is simple to operate, low in cost, and has the potential for industrial production. Attached Figure Description

[0023] Figure 1 This is a physical image of the mold used and the prepared Marangoni hydrogel reactor in Embodiment 1 of the present invention;

[0024] Figure 2 These are electron microscope images of the asymmetric cellulose polymer network in Example 1 of the present invention. a is an electron microscope image of the rear polymer network, and b is an electron microscope image of the front polymer network.

[0025] Figure 3 These are speed and rotation time diagrams for Embodiments 1-5 of the present invention;

[0026] Figure 4 Figure 1 shows the change in absorbance over time during the degradation of MB to colorless in Examples 1 (Figure a) and Comparative Example 1 (Figure b); Figure 2 shows the time required for degradation of MB to colorless in Examples 1-4 and Comparative Example 1, and the time required for degradation of MO to colorless in Example 5.

[0027] Figure 5 This is a conceptual diagram (Figure a) of in-situ fuel dripping in Embodiment 1 of the present invention, and a statistical diagram of the rotation speed and rotation time after dripping (Figure b).

[0028] Figure 6 This is a kinetic calculation diagram after 5 cycles of MB catalysis in Example 1 of the present invention. Detailed Implementation

[0029] The present invention will now be further described in conjunction with specific embodiments and accompanying drawings.

[0030] Example 1: The Marangoni hydrogel reactor with high mass transfer provided in this example is a cellulose hydrogel rotor loaded with fuel ethanol that can generate the Marangoni effect. The cellulose hydrogel rotor includes a front end and a rear end. The front end is a cross-linked cellulose hydrogel and the rear end is a cellulose hydrogel loaded with palladium nanoparticles.

[0031] The preparation method of the above-mentioned Marangoni hydrogel reactor specifically includes the following steps:

[0032] (1) Dissolve cellulose in a mixed aqueous solution of sodium hydroxide and urea at -12.5℃, homogenize three times to disperse the cellulose evenly, and prepare a 2wt% cellulose solution.

[0033] (2) The cellulose solution from step (1) is mixed with the palladium chloride solution, wherein the palladium chloride is dissolved in hydrochloric acid aqueous solution with pH 3 at 70°C. The mixed solution is then stirred at 60°C for 4 hours until it turns black, to obtain a cellulose mixed solution loaded with palladium nanoparticles, wherein the concentration of palladium chloride is 10.2 mM. The mixed solution is injected into mold 1, and after gelation, it is demolded to obtain the rear end of the rotor.

[0034] (3) Place the rear end of the rotor obtained in step (2) into mold 2, add epichlorohydrin at a mass ratio of 1:0.036 to the cellulose solution in step (1), stir thoroughly at 0°C for 2 hours to obtain a cross-linked cellulose solution, then inject the solution into the empty part of mold 2, and after gelation, soak it in water until there is no residue of sodium hydroxide urea solution to obtain Marangoni cellulose hydrogel rotor.

[0035] (4) Soak the hydrogel rotor obtained in step (3) in ethanol for 30 minutes to obtain a hydrogel rotor loaded with fuel, which is the Marangoni hydrogel reactor.

[0036] The application steps are as follows: the Marangoni hydrogel reactor is transferred to a 30 mmol / L MB dye solution to allow it to undergo a catalytic degradation reaction at the air-water interface.

[0037] Comparative Example 1, by omitting the injection molding operations in steps (2) and (3) of Example 1, yielded a porous hydrogel loaded with a palladium catalyst. Specifically, the following steps were performed:

[0038] (1) Dissolve cellulose in a mixed aqueous solution of sodium hydroxide and urea at -12.5℃, homogenize three times to disperse the cellulose evenly, and prepare a 2wt% cellulose solution.

[0039] (2) The cellulose solution from step (1) is mixed with the palladium chloride solution, wherein the palladium chloride is dissolved in hydrochloric acid aqueous solution with pH 3 at 70°C. The mixed solution is then stirred at 60°C for 4 hours until it turns black, to obtain a cellulose mixed solution loaded with palladium nanoparticles, wherein the concentration of palladium chloride is 10.2 mM. After the mixed solution is refrigerated to form a gel, a hydrogel loaded with palladium catalyst is obtained.

[0040] (3) Place the rear end of the rotor obtained in step (2) into mold 2, add epichlorohydrin at a mass ratio of 1:0.036 to the cellulose solution in step (1), and stir thoroughly at 0°C for 2 hours to obtain a cross-linked cellulose solution. Then, refrigerate the solution to form a gel, first placing the hydrogel from step (2) into it, and after gelation, soak it in water until there is no residue of sodium hydroxide urea solution to obtain a porous hydrogel supported on palladium catalyst.

[0041] The application method is as follows: the porous hydrogel is transferred into a 30 mmol / L MB dye solution to allow it to undergo a catalytic degradation reaction in the solution.

[0042] Example 2: The Marangoni hydrogel reactor with high-efficiency mass transfer provided in this example is a cellulose hydrogel rotor loaded with fuel ethanol that can generate the Marangoni effect. The cellulose hydrogel rotor includes a front end and a rear end. The front end is a cross-linked cellulose hydrogel and the rear end is a cellulose hydrogel loaded with palladium nanoparticles.

[0043] The preparation method of the above-mentioned Marangoni hydrogel reactor specifically includes the following steps:

[0044] (1) Dissolve cellulose in a mixed aqueous solution of sodium hydroxide and urea at -12.5℃, homogenize three times to disperse the cellulose evenly, and prepare a 2wt% cellulose solution.

[0045] (2) The cellulose solution from step (1) is mixed with the palladium chloride solution, wherein the palladium chloride is dissolved in hydrochloric acid aqueous solution with pH 3 at 70°C. The mixed solution is then stirred at 60°C for 4 hours until it turns black, to obtain a cellulose mixed solution loaded with palladium nanoparticles, wherein the concentration of palladium chloride is 2.4 mM. The mixed solution is injected into mold 1, and after gelation, it is demolded to obtain the hydrogel at the rear end of the rotor.

[0046] (3) Place the rear end of the rotor obtained in step (2) into mold 2, add epichlorohydrin to the cellulose solution in step (1) at a mass ratio of 1:0.072, and stir thoroughly at 0°C for 2 hours to obtain a cross-linked cellulose solution. Then inject the solution into the empty part of mold 2, and after gelation, soak it in water until there is no residue of sodium hydroxide urea solution to obtain Marangoni cellulose hydrogel rotor;

[0047] (4) Soak the hydrogel rotor obtained in step (3) in ethanol for 30 minutes to obtain a hydrogel rotor loaded with fuel, which is the Marangoni hydrogel reactor.

[0048] The application steps are as follows: the Marangoni hydrogel reactor is transferred to a 10 mmol / L MB dye solution to allow it to undergo catalytic degradation at the air-water interface, with a degradation rate of 99.9% within 3.5 min.

[0049] Example 3: The Marangoni hydrogel reactor with high-efficiency mass transfer provided in this example is a cellulose hydrogel rotor loaded with fuel n-propanol that can generate the Marangoni effect. The cellulose hydrogel rotor includes a front end and a rear end. The front end is a cross-linked cellulose hydrogel and the rear end is a cellulose hydrogel loaded with palladium nanoparticles.

[0050] The preparation method of the high-efficiency mass transfer Marangoni hydrogel reactor in this embodiment includes the following steps:

[0051] (1) Dissolve cellulose in a mixed aqueous solution of sodium hydroxide and urea at -12.5℃, homogenize three times to disperse the cellulose evenly, and prepare a 2wt% cellulose solution.

[0052] (2) The cellulose solution from step (1) is mixed with the palladium chloride solution, wherein the palladium chloride is dissolved in hydrochloric acid aqueous solution with pH 3 at 70°C. The mixed solution is then stirred at 60°C for 4 hours until it turns black, to obtain a cellulose mixed solution loaded with palladium nanoparticles, wherein the concentration of palladium chloride is 20.5 mM. The mixed solution is injected into mold 1, and after gelation, it is demolded to obtain the hydrogel at the rear end of the rotor.

[0053] (3) Place the rear end of the rotor obtained in step (2) into mold 2, add epichlorohydrin to the cellulose solution in step one at a mass ratio of 1:0.09, and stir thoroughly at 0°C for 2 hours to obtain a cross-linked cellulose solution. Then inject the solution into the empty part of mold 2, and after gelation, soak it in water until there is no residue of sodium hydroxide urea solution to obtain Marangoni cellulose hydrogel rotor;

[0054] (4) Soak the hydrogel rotor obtained in step (3) in n-propanol for 10 minutes to obtain a hydrogel rotor loaded with fuel, which is the Marangoni hydrogel reactor.

[0055] The application steps are as follows: the Marangoni hydrogel reactor is transferred to a 35 mmol / L MB dye solution to allow it to undergo catalytic degradation at the air-water interface, with a degradation rate of 99.9% within 2.3 min.

[0056] Example 4: The Marangoni hydrogel reactor with high mass transfer provided in this example is a cellulose hydrogel rotor loaded with fuel isopropanol that can generate the Marangoni effect. The cellulose hydrogel rotor includes a front end and a rear end. The front end is a cross-linked cellulose hydrogel and the rear end is a cellulose hydrogel loaded with silver nanoparticles.

[0057] The preparation method of the high-efficiency mass transfer Marangoni hydrogel reactor in this embodiment includes the following steps:

[0058] (1) Dissolve cellulose in a mixed aqueous solution of sodium hydroxide and urea at -12.5℃, homogenize three times to disperse the cellulose evenly, and prepare a 3wt% cellulose solution.

[0059] (2) The cellulose solution from step one is mixed with the silver nitrate solution. The mixture is then stirred at 60°C for 4 hours until it turns black, resulting in a cellulose mixture loaded with silver nanoparticles. The concentration of silver nitrate is 5.1 mM. The mixture is injected into mold 1, and after gelation, it is demolded to obtain the hydrogel at the rear end of the rotor.

[0060] (3) Place the rear end of the rotor obtained in step (2) into mold 2, add epichlorohydrin to the cellulose solution in step (1) at a mass ratio of 1:0.036, and stir thoroughly at 0°C for 2 hours to obtain a cross-linked cellulose solution. Then inject the solution into the empty part of mold 2, and after gelation, soak it in water until there is no residue of sodium hydroxide urea solution to obtain Marangoni cellulose hydrogel rotor;

[0061] (4) Soak the hydrogel rotor obtained in step (2) in isopropanol for 20 minutes to obtain a hydrogel rotor loaded with fuel, which is the Marangoni hydrogel reactor.

[0062] The application steps are as follows: the Marangoni hydrogel reactor is transferred to a 40 mmol / L MB dye solution to allow it to undergo catalytic degradation at the air-water interface, with a degradation rate of 99.9% within 6.8 min.

[0063] Example 5: The Marangoni hydrogel reactor with high-efficiency mass transfer provided in this example is a cellulose hydrogel rotor loaded with fuel hexafluoroisopropanol that can generate the Marangoni effect. The cellulose hydrogel rotor includes a front end and a rear end. The front end is a cross-linked cellulose hydrogel and the rear end is a cellulose hydrogel loaded with platinum nanoparticles.

[0064] The preparation method of the high-efficiency mass transfer Marangoni hydrogel reactor in this embodiment includes the following steps:

[0065] (1) Dissolve cellulose in a mixed aqueous solution of sodium hydroxide and urea at -12.5℃, homogenize three times to disperse the cellulose evenly, and prepare a 2wt% cellulose solution.

[0066] (2) Mix the cellulose solution from step (1) with the chloroplatinic acid solution evenly, and then stir for 3 hours to obtain a cellulose mixed solution loaded with platinum nanoparticles, wherein the concentration of chloroplatinic acid is 15 mM. Inject the mixed solution into mold 1, and after gelation, demold to obtain the rear hydrogel of the rotor.

[0067] (3) Place the rear end of the rotor obtained in step (2) into mold 2, add epichlorohydrin to the cellulose solution in step one at a mass ratio of 1:0.036, and stir thoroughly at 0°C for 2 hours to obtain a cross-linked cellulose solution. Then inject the solution into the empty part of mold 2, and after gelation, soak it in water until there is no residue of sodium hydroxide urea solution to obtain Marangoni cellulose hydrogel rotor;

[0068] (4) The hydrogel rotor obtained in step (3) is immersed in hexafluoroisopropanol for 30 minutes to obtain a hydrogel rotor loaded with fuel, which is the Marangoni hydrogel reactor.

[0069] The application steps are as follows: the Marangoni hydrogel reactor is transferred to a 50 mmol / L MO (methyl orange) dye solution to allow it to undergo catalytic degradation at the air-water interface, with a degradation rate of 99.9% within 3.9 min.

[0070] The materials prepared in Examples 1-5 and Comparative Example 1 were tested and characterized, and the results are as follows: Figures 1-6 As shown.

[0071] Figure 1 Images of the mold used and the materials obtained in Example 1. Figure 1 Image (a) shows an optical image of the prepared rotor, clearly revealing that it is composed of two different hydrogels. Figure 1 Figure (b1) shows mold 1 required for preparing the back-end hydrogel. Figure 1 Figure (b2) shows mold 2 required for preparing the front-end hydrogel. In molds 1 and 2, the thickness of the toothed ring is 2 mm, the radius of the toothed ring is 5 mm, and the length of the tooth on the side closest to the toothed ring is 5 mm.

[0072] from Figure 2 It is evident that the Marangoni cellulose hydrogel rotor is composed of two different polymer networks. Figure 2 Image (a) shows a SEM image of the rotor's rear end. When cellulose changes from a sol state to a solid hydrogel, hydrogen bonds reform between cellulose molecules. However, Pd... 2+ The reduction process leads to the reduction of -OH groups, reducing the formation of hydrogen bonds in the cellulose chains and thus creating a loose microstructure. In contrast, Figure 2(b) shows the SEM image of the front hydrogel, which reveals a large number of three-dimensional porous structures. This is because during the chemical cross-linking process, -OH is converted into C=O and COC, resulting in high cross-linking between cellulose chains and forming a three-dimensional porous network. This asymmetric polymer network structure endows the rotor with a significant gradient surface tension, enabling the rotor to rotate rapidly.

[0073] from Figure 3 It is evident that the hydrogel rotors with different loads of PdNPs have different effects on the rotor speed and rotation time due to the different porosity. Among them, the hydrogel rotor with the greater difference between the front and rear ends has the highest speed, reaching 6790 r / h.

[0074] Figure 4 This refers to the time required for the degradation of dye MB in Examples 1 and Comparative Example 1, where... Figure 4 (a) in the text is Example 1. Figure 4 (b) is a comparison example 1. It can be seen that the rotating rotor causes a rapid decrease in the absorbance of the dye, reaching a degradation rate of 99.9% within 4.5 minutes. However, the degradation rate of the dye by the stationary porous hydrogel lags far behind that of the rotating rotor, requiring at least 20 minutes to reach 99.9%. Figure 4 In the figure (c), the time required for the corresponding dyes in Examples 1-5 and Comparative Example 1 to degrade is represented.

[0075] from Figure 5 It can be seen that due to the excellent hydrophilicity of cellulose materials, the in-situ dripping method greatly simplifies the fuel reloading process in the reactor and reduces fuel waste. Adding only 80 μL of ethanol can make the MCR speed reach 4000 r / h again and the runtime can exceed 13.0 min.

[0076] from Figure 6 It can be seen that the rotor has good cycle stability, and the degradation rate of MB can still be maintained above 87% after five catalytic cycles, which is conducive to recycling.

Claims

1. A method for preparing a highly efficient mass transfer Marangoni hydrogel reactor, characterized in that, The reactor is a cellulose hydrogel rotor capable of generating the Marangoni effect and loaded with fuel. The cellulose hydrogel rotor includes a front end and a rear end; the front end is a cross-linked cellulose hydrogel, and the rear end is a cellulose hydrogel loaded with catalyst noble metal nanoparticles. The preparation method of the Marangoni hydrogel reactor includes the following steps: (1) The cellulose solution is mixed and stirred with the noble metal salt solution and reduced to obtain a cellulose mixed solution loaded with noble metal nanoparticles. Then the above mixed solution is injected into mold 1 that can produce the Marangoni effect. After gelation, the mold is demolded to obtain the rear end of the cellulose hydrogel rotor. (2) The rear end of the cellulose hydrogel rotor is placed into the mold 2 that can produce the Marangoni effect. Then, the cross-linked cellulose solution is injected into the empty part of the mold 2. After gelation, it is soaked in water to obtain the Marangoni cellulose hydrogel rotor. (3) Immerse the Marangoni hydrogel rotor in fuel to obtain a Marangoni cellulose hydrogel rotor loaded with fuel, which is a Marangoni hydrogel reactor with high-efficiency mass transfer; the fuel is isopropanol, n-propanol, hexafluoroisopropanol, ethanol, dimethyl sulfoxide or acetone; the precious metal is palladium, silver or platinum; in steps (1)-(2), the mold 1 that generates the Marangoni effect and the mold 2 that can generate the Marangoni effect are both gear-shaped structures, including a gear ring and several gear teeth, the gear teeth are located on the outer edge of the gear ring, and the gear ring is a disc-shaped structure.

2. The preparation method according to claim 1, characterized in that, In step (1), the cellulose solution is prepared by dissolving cellulose in a mixed aqueous solution of sodium hydroxide and urea, and then homogenizing to uniformly disperse the cellulose to obtain a cellulose solution; the mass percentage of cellulose in the cellulose solution is 1-3 wt%; the noble metal salt is palladium chloride, silver nitrate and chloroplatinic acid; the molar concentration of the noble metal salt in the mixed solution is 2.4-20.5 mmol / L.

3. The preparation method according to claim 1, characterized in that, In steps (1)-(2), the cross-section of the gear teeth of mold 1 is a triangular structure with a vertex angle of 20-30°. The length of the side of the gear teeth near the gear ring is equal to the radius of the gear ring. The cross-section of the gear teeth of mold 2 is an irregular triangular structure with an arc-shaped outer edge. The thickness of the gear ring is 2-4mm and the radius of the gear ring is 5-6mm.

4. The preparation method according to claim 1, characterized in that, In step (2), the method for preparing the cross-linked cellulose solution is as follows: epichlorohydrin is added to the cellulose solution and stirred thoroughly to obtain the cross-linked cellulose solution; wherein the mass of epichlorohydrin is 2-5 wt% of the mass of the cellulose solution.

5. The preparation method according to claim 1, characterized in that, In step (3), the soaking time is 15-60 minutes.

6. The application of the Marangoni hydrogel reactor prepared by the method of claim 1 in the degradation of organic pollutants.

7. The application according to claim 6, characterized in that, The application method is as follows: the Marangoni hydrogel reactor is placed in a solution containing organic pollutants, and the Marangoni hydrogel reactor carries out a catalytic degradation reaction at the air-water interface through self-rotation.

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