Preparation method of integrated titanium dioxide-based electrochemical separation membrane

Abstract

This invention proposes a method for preparing an integrated titanium dioxide-based electrochemical separation membrane. Using tetrabutyl titanate as the titanium source, a hydrothermal method is used to prepare titanium dioxide nanocrystals. This nanocrystal serves as the membrane aggregate, and a membrane casting method is used to prepare the integrated porous electrochemical separation membrane. The preparation method is simple, low-cost, flexible, and controllable.

Description

Technical Field

[0001] The present invention relates to the technical field of multifunctional membrane separation, and in particular to a method for preparing an integrated titanium dioxide-based electrochemical separation membrane. Background Art

[0002] Membrane separation technology is widely used in various water and wastewater treatment applications, such as desalination, oil-water separation, and disinfection, due to its advantages such as simple operation, low energy consumption, stable effluent quality, low cost, and small ecological footprint. Low-pressure membrane separation technologies such as microfiltration and ultrafiltration offer high permeability, low operating pressure, and stable pathogen removal, making them the primary technologies currently used in the membrane separation field. However, due to their large pore sizes, traditional microfiltration and ultrafiltration membranes are unable to remove small molecule pollutants. These small molecule pollutants not only deposit and adsorb on the membrane surface or within the pores, causing serious membrane fouling, but also penetrate the separation membrane into the permeate, where they are subsequently exposed to the environment, posing a significant threat to the ecological environment and human health.

[0003] Electrochemical separation membranes integrate membrane separation technology and electrochemical advanced oxidation. During the filtration process, electrochemical separation membranes perform the dual functions of a separation membrane and an electrode, utilizing electrochemical reactions to oxidize and decompose organic pollutants. This effectively improves the membrane's removal efficiency for small-molecule organic pollutants while simultaneously mitigating membrane fouling. Electrochemical separation membrane preparation methods are primarily categorized into three categories: membrane casting, membrane modification, and membrane integration. Among these, membranes prepared using membrane casting are monolithic porous conductive membranes, such as carbon-based membranes and titania membranes. Compared to conductive membranes prepared using membrane modification and membrane integration methods, monolithic porous conductive membranes have a higher electroactive surface area, making them more conducive to electrochemical reactions. However, carbon-based membranes can oxidize the carbon material under anodic polarization conditions, leading to corrosion and damage to the membrane electrode. Titania membranes often require hydrogen as a reducing agent for their industrial production, hindering their commercialization. Therefore, the development of novel materials for the preparation of monolithic porous electrochemical separation membranes is necessary. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing an integrated titanium dioxide-based electrochemical separation membrane to solve the preparation problems existing in existing electrochemical separation membranes.

[0005] In order to solve the above technical problems, the present invention provides a method for preparing an integrated titanium dioxide-based electrochemical separation membrane, using tetrabutyl titanate as a titanium source, a hydrothermal method to prepare titanium dioxide nanocrystals, and using this as a membrane aggregate, a membrane casting method is used to prepare an integrated porous electrochemical separation membrane.

[0006] The preparation method further specifically comprises:

[0007] The first step is to prepare titanium dioxide nano-single crystals. Tetrabutyl titanate is added to a hydrofluoric acid aqueous solution at room temperature, transferred to a reactor, stirred for reaction, and then transferred to an oven for further reaction. After the reaction is completed, the mixture is cooled and centrifuged to obtain a powder. The powder is repeatedly rinsed, vacuum-dried, and ground to obtain titanium dioxide nano-single crystal powder.

[0008] The second step is the preparation of a titanium dioxide-based electrochemical separation membrane. The titanium dioxide nano-single crystal powder prepared in the first step is mixed with paraffin oil, ground, pressed into tablets, and calcined to obtain a titanium dioxide-based ceramic membrane.

[0009] In the first step, the volume ratio of tetrabutyl titanate and hydrofluoric acid aqueous solution is 1:1-2:1.

[0010] In the first step, the stirring time in the reactor is 0.5-1 hour.

[0011] In the first step, the reaction temperature in the oven is 150° C.-220° C., and the reaction time is 18-32 hours.

[0012] In the first step, anhydrous ethanol, NaOH solution and deionized water are used for rinsing respectively.

[0013] In the second step, the pressure used during tableting is 6-9 bar.

[0014] In the second step, the calcination temperature is 800-1200° C. and the calcination time is 4-8 hours.

[0015] Beneficial effects of the present invention

[0016] The preparation method of the integrated titanium dioxide-based electrochemical separation membrane provided by the present invention is simple, low-cost, flexible, controllable, and easy to manage;

[0017] The integrated titanium dioxide-based electrochemical separation membrane provided by the present invention has good electrocatalytic oxidation ability and permeability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention relates to the removal rate of methylene blue (50 mg / L) by the integrated titanium dioxide-based electrochemical separation membrane prepared by the preparation method when an external voltage of 3 V is applied;

[0019] Figure 2 The present invention relates to a pure water flux-operating pressure relationship diagram of an integrated titanium dioxide-based electrochemical separation membrane prepared by the preparation method. DETAILED DESCRIPTION

[0020] The invention uses tetrabutyl titanate as a titanium source, adopts a hydrothermal method to prepare titanium dioxide nano single crystals, uses the same as membrane aggregate, and adopts a membrane casting method to prepare an integrated porous electrochemical separation membrane.

[0021] The technical solution of the present invention comprises the following steps:

[0022] Preparation of titanium dioxide nanocrystals: At room temperature (10-15°C), slowly add 10-40 mL of tetrabutyl titanate to 10-20 mL of a 20-30 wt.% hydrofluoric acid aqueous solution. The mixed solution is transferred to a polytetrafluoroethylene reactor and magnetically stirred for 0.5-1 hour. The pale yellow precursor is then transferred to an oven and reacted at 150-220°C for 18-32 hours. After the reaction is complete, the product is cooled to room temperature and centrifuged to collect the white powder. The product is then rinsed repeatedly with anhydrous ethanol, 0.1 M NaOH solution, and deionized water to remove unreacted fluoride ions. The centrifuged product is then transferred to a vacuum drying oven and dried at 40-80°C for 12-24 hours. After drying, the product is ground to obtain titanium dioxide nanocrystal powder.

[0023] Preparation of a titanium dioxide-based electrochemical separation membrane: 0.5-1.0g of titanium dioxide nanocrystalline powder was mixed with 1-4wt% paraffin oil as a binder. The mixture of titanium dioxide powder and paraffin oil was ground in an agate mortar for 30 minutes to achieve uniform mixing. The mixture was placed in a mold with a diameter of 1.12cm and pressed into a tablet under a pressure of 6-9 bar. The green pellet was placed in a tubular furnace under nitrogen and calcined at 800-1200°C for 4-8 hours to obtain a titanium dioxide-based ceramic membrane.

[0024] The following examples and drawings are used to describe the embodiments of the present invention in detail, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0025] Example 1

[0026] Preparation of titanium dioxide nanocrystals: At room temperature (10-15°C), 25 mL of tetrabutyl titanate was slowly added to 15 mL of a 24 wt.% hydrofluoric acid aqueous solution. The mixed solution was transferred to a polytetrafluoroethylene reactor and magnetically stirred for 0.5 hours. After that, the light yellow precursor was transferred to an oven and reacted at 180°C for 24 hours. After the reaction, it was cooled to room temperature and the white powder was collected by centrifugation. The product was repeatedly rinsed with anhydrous ethanol, 0.1M NaOH solution, and deionized water to remove unreacted fluoride ions. The centrifuged product was then transferred to a vacuum drying oven and dried at 60°C for 18 hours. After drying, it was ground to obtain titanium dioxide nanocrystal powder.

[0027] Preparation of a titanium dioxide-based electrochemical separation membrane: 0.6 g of titanium dioxide nanocrystal powder was mixed with 3 wt.% paraffin oil as a binder. The mixture was ground in an agate mortar for 30 minutes to achieve uniform mixing. The mixture was then placed in a 1.12 cm diameter mold and pressed into a tablet under a pressure of 7 bar. The green pellet was placed in a tubular furnace under nitrogen and calcined at 1050°C for 6 hours to produce a titanium dioxide-based ceramic membrane.

[0028] Depend on Figure 1 It can be seen that the integrated titanium dioxide-based electrochemical separation membrane has a good removal ability for methylene blue when an external voltage of 3V is applied, that is, the membrane has a good electrocatalytic oxidation ability and can be used to remove difficult-to-degrade organic pollutants such as dyes. Figure 2 The pure water flux of the integrated titanium dioxide-based electrochemical separation membrane is about 873 L m -2 h -1 bar -1 , it can be seen that it has good permeability. The separation membrane also has good pressure resistance. Under the condition that the pressure does not exceed 1 bar, the separation membrane will not deform due to mechanical pressure and cause a decrease in flux.

[0029] All of the above are intended to be primary implementations of this intellectual property and do not constitute limitations on other implementations of such new products and / or methods. Those skilled in the art will utilize this important information and modify the above to achieve similar implementations. However, all modifications or adaptations based on this invention to new products are reserved.

[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A method for preparing an integrated titanium dioxide-based electrochemical separation membrane, characterized in that: Titanium dioxide nano-single crystal powder was prepared by hydrothermal method with tetrabutyl titanate as titanium source and used as membrane aggregate. The titanium dioxide nano single crystal powder is mixed with paraffin oil, ground, tableted, and calcined to obtain a titanium dioxide-based ceramic film.

2. The method for preparing an integrated titanium dioxide-based electrochemical separation membrane according to claim 1, wherein: The method for preparing the titanium dioxide nano-single crystal powder further comprises: Tetrabutyl titanate was added to a hydrofluoric acid aqueous solution at room temperature, transferred to a reactor, stirred for reaction, transferred to an oven for further reaction, cooled after the reaction was completed, centrifuged to obtain powder, repeatedly rinsed, vacuum dried, and ground to obtain titanium dioxide nano single crystal powder.

3. The method for preparing an integrated titanium dioxide-based electrochemical separation membrane according to claim 2, wherein: The volume ratio of tetrabutyl titanate and hydrofluoric acid aqueous solution is 1:1-2:

1.

4. The method for preparing an integrated titanium dioxide-based electrochemical separation membrane according to claim 2, wherein: The stirring time in the reactor is 0.5-1 hour.

5. The method for preparing an integrated titanium dioxide-based electrochemical separation membrane according to claim 2, wherein: The reaction temperature in the oven is 150°C-220°C, and the reaction time is 18-32h.

6. The method for preparing an integrated titanium dioxide-based electrochemical separation membrane according to claim 2, wherein: Anhydrous ethanol, NaOH solution and deionized water were used for rinsing respectively.

7. The method for preparing an integrated titanium dioxide-based electrochemical separation membrane according to claim 2, wherein: The pressure used during tableting is 6-9 bar.

8. The method for preparing an integrated titanium dioxide-based electrochemical separation membrane according to claim 2, wherein: The calcination temperature is 800-1200°C, and the calcination time is 4-8 hours.

9. An integrated titanium dioxide-based electrochemical separation membrane prepared by the method according to any one of claims 1 to 8.

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