A method for preparing chlorine dioxide by catalytic activation of chlorite.

Abstract

This invention discloses a method for catalytically activating chlorite to produce chlorine dioxide. Driven by external force, a polymer with piezoelectric, hydrophobic, and electron-withdrawing properties is used as a catalyst to catalyze the activation of chlorite to produce chlorine dioxide. The advantages of this invention are that it can generate piezoelectric catalysis derived from force-electroelectric coupling and contact-induced electrocatalysis, promoting charge separation and transfer. The positively charged layer formed on the polymer surface can exchange electrons with chlorite ions, i.e., steal their electrons, thereby forming chlorine dioxide. Simultaneously, due to the force-electroelectric coupling effect, it can also generate reactive species such as hydroxyl radicals and superoxide radicals.

Description

Technical Field

[0001] This invention relates to the field of environmental functional catalytic production of chemicals, and in particular to a method for catalytically activating chlorite to prepare chlorine dioxide. Background Technology

[0002] Novel advanced reduction-oxidation technologies for chlorite activation, such as catalytic activation of chlorite with metal-based catalysts, can produce high-valence metal oxides (such as high-valence iron oxides and high-valence cobalt oxides) and chlorine dioxide, which can be used for selective removal of organic pollutants and sustainable disinfection and sterilization of microorganisms. However, metal-based methods are subject to ion leaching, and there is an urgent need to develop non-metal-based catalytic activation methods for chlorite.

[0003] Furthermore, chlorine dioxide is an internationally recognized, highly efficient, broad-spectrum, safe, and long-lasting bactericide, disinfectant, and algaecide. It is also a selective oxidant, applicable to drinking water disinfection and treatment, removal of organic pollutants, sanitation and disinfection, and food preservation, and is recognized by the World Health Organization, the US Food and Drug Administration, and the US Environmental Protection Agency. Currently, the most common methods for preparing chlorine dioxide are chemical methods, which include reduction, oxidation, and electrolysis, primarily involving the reduction of chlorate or the oxidation of chlorite. The methods for preparing chlorine dioxide from chlorite mainly rely on ultraviolet catalysis or acidic catalysis. Due to its incompressible nature, chlorine dioxide is inconvenient to transport and is generally prepared as an aqueous solution or used immediately after preparation. Despite its significant advantages, the preparation characteristics and inherent properties of chlorine dioxide limit its development and application. Therefore, how to prepare and apply chlorine dioxide in a green, environmentally friendly, efficient, safe, and scenario-adaptable manner is an urgent research direction to further promote its multi-scenario application. Summary of the Invention

[0004] The purpose of this invention is to provide a method for catalytically activating chlorite to prepare chlorine dioxide. Based on the principle of vibrational catalysis derived from the piezoelectric and contact electrification mechanism of the force-electric coupling catalysis mechanism, the method utilizes ultrasonic / ball milling technology to drive polymer catalysis of chlorite, and generates chlorine dioxide through electron transfer.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0006] A method for catalytically activating chlorite to produce chlorine dioxide, characterized in that a polymer with piezoelectric, hydrophobic and electron-withdrawing properties is used as a catalyst to catalytically activate chlorite to produce chlorine dioxide.

[0007] Preferably, the specific steps are as follows: after adding polymer powder material to water and mixing it thoroughly, chlorite is added and an external force is activated to start the reaction to produce chlorine dioxide.

[0008] Preferably, the polymer is PVDF material, PTFE material, or a mixture of the two in any proportion.

[0009] Preferably, the external force is driven by ultrasound or ball milling.

[0010] Preferably, the ultrasonic frequency is ≥20kHz and the ball mill rotation speed is ≥100rpm.

[0011] Preferably, the polymer powder has a particle size of 1~900mm and an addition amount of 10~1000mg / L.

[0012] Preferably, the concentration of the chlorite is 1 μmol / L to 10 mmol / L.

[0013] Preferably, after the polymer powder material is thoroughly mixed in water, sulfuric acid with a concentration of 50 μmol / L can also be added.

[0014] Preferably, the ultrasonic or ball milling driving time is 30~240 min.

[0015] In summary, this invention has the following beneficial effects: It utilizes external forces such as ultrasound or ball milling (contact, friction, vibration, etc.) to drive the process, and uses polymers with piezoelectric, hydrophobic, and electron-withdrawing properties as catalysts to catalyze the activation of chlorite. This generates piezoelectric catalysis derived from force-electric coupling and electrocatalysis through contact, promoting charge (electron) separation and transfer. The positively charged layer formed on the polymer surface can react with chlorite ions (ClO2). - The electron exchange (transfer) is completed, that is, the electrons are stolen, thus forming chlorine dioxide (ClO2); at the same time, due to the mechano-electrostatic coupling effect, hydroxyl radicals (·OH) and superoxide radicals (O2) can also be generated. ·- Active species such as ) Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the principle of catalytic activation of chlorite to prepare chlorine dioxide according to the present invention; Detailed Implementation

[0017] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. These embodiments do not constitute a limitation on the present invention.

[0018] A method for catalytically activating chlorite to produce chlorine dioxide involves using an external force driven by ultrasound, ball milling, contact, friction, or vibration. A polymer with piezoelectric, hydrophobic, and electron-withdrawing properties is used as a catalyst to catalyze the activation of chlorite to produce chlorine dioxide. This method can generate piezoelectric catalysis derived from force-electric coupling and electrocatalysis through contact, promoting charge (electron) separation and transfer. The positively charged layer formed on the polymer surface can react with chlorite ions (ClO2). -The electron exchange (transfer) is completed, that is, the electrons are stolen, thus forming chlorine dioxide (ClO2); at the same time, due to the mechano-electrostatic coupling effect, hydroxyl radicals (·OH) and superoxide radicals (O2) can also be generated. ·- Active species such as ) Example 1

[0019] 10 mg of PTFE with a particle size of 5 mm was added to 100 mL of water and mechanically stirred until homogeneous. Then, 100 mmol of chlorite was added, and the mixture was placed in a 28 kHz ultrasonic bath for at least 60 min to catalytically activate the chlorite and produce chlorine dioxide. The solution was tested in a UV-Vis spectrum at 360 nm and showed a characteristic absorption peak with a full width at half maximum (FWHM) of 80 nm and no impurity peaks, indicating the production of chlorine dioxide. Example 2

[0020] 5 mg of PTFE with a particle size of 100 mm was added to 100 mL of water and mechanically stirred until homogeneous. Then, 100 mmol of chlorite and 5 mmol of sulfuric acid solution (1 mol / L) were added. The mixture was placed in a 28 kHz ultrasonic bath and reacted for at least 30 min to catalytically activate the chlorite and produce chlorine dioxide. The solution was tested in a UV-Vis spectrum at 360 nm and showed a characteristic absorption peak with a full width at half maximum (FWHM) of 80 nm and no impurity peaks, indicating the production of chlorine dioxide. Example 3

[0021] 500 mg of PTFE with a particle size of 300 mm was added to 100 mL of water and mechanically stirred until homogeneous. Then, 500 mmol of chlorite was added, and the mixture was placed in a ball mill at 200 rpm for at least 160 min to catalytically activate the chlorite and obtain chlorine dioxide. The solution was tested in a UV-Vis spectrum at 360 nm and showed a characteristic absorption peak with a full width at half maximum (FWHM) of 80 nm and no impurity peaks, indicating the formation of chlorine dioxide. Example 4

[0022] 1000 mg of PTFE with a particle size of 50 mm was added to 100 mL of water and mechanically stirred until homogeneous. Then, 100 mmol of chlorite and 5 mmol of sulfuric acid solution (1 mol / L) were added. The mixture was then placed in a ball mill at 200 rpm and reacted for at least 240 min to catalytically activate the chlorite and obtain chlorine dioxide. The solution was tested in a UV-Vis spectrum at 360 nm and showed a characteristic absorption peak with a full width at half maximum (FWHM) of 80 nm and no impurity peaks, indicating the formation of chlorine dioxide. Example 5

[0023] Add 50 mg of PTFE with a particle size of 5 mm to 100 mL of water, stir mechanically to mix, then add 100 mmol of chlorite, 20 mg / L of methyl violet, and 5 mmol of sulfuric acid solution (1 mol / L). Place the mixture in a 28 kHz bath ultrasonic generator and react for more than 60 min to catalyze and activate chlorite to remove more than 90% of methyl violet. Example 6

[0024] Add 50 mg of a mixture of PTFE and PVDF with a particle size of 10 mm in any proportion to 100 mL of water. After mechanically stirring and mixing, add 100 mmol of chlorite, 20 mg / L of methyl violet, and 5 mmol of sulfuric acid solution (1 mol / L). Place the mixture in a ball mill at 200 rpm and react for more than 120 min to catalytically activate chlorite to remove more than 90% of methyl violet. Example 7

[0025] 50 mg of PVDF with a particle size of 100 mm was added to 100 mL of water and mechanically stirred until homogeneous. Then, 500 mmol of chlorite was added, and the mixture was placed in a 28 kHz ultrasonic bath for at least 120 min to catalytically activate the chlorite and produce chlorine dioxide. The solution was tested in a UV-Vis spectrum at 360 nm and showed a characteristic absorption peak with a full width at half maximum (FWHM) of 80 nm and no impurity peaks, indicating the production of chlorine dioxide. Example 8

[0026] 100 mg of PVDF with a particle size of 500 mm was added to 100 mL of water and mechanically stirred until homogeneous. Then, 1 mmol of chlorite was added, and the mixture was placed in a ball mill at 200 rpm for at least 240 min to catalytically activate the chlorite and obtain chlorine dioxide. The solution was tested in a UV-Vis spectrum at 360 nm and showed a characteristic absorption peak with a full width at half maximum (FWHM) of 80 nm and no impurity peaks, indicating the formation of chlorine dioxide.

[0027] Driven by external forces such as ultrasound or ball milling (contact, friction, vibration, etc.), and using polymers with piezoelectric, hydrophobic, and electron-withdrawing properties as catalysts, this method catalyzes the activation of chlorite. It generates both piezoelectric catalysis derived from force-electric coupling and electrocatalysis through contact, promoting charge (electron) separation and transfer. The positively charged layer formed on the polymer surface can react with chlorite ions (ClO2). - The electron exchange (transfer) is completed, that is, the electrons are "snatched" from the body, thus forming chlorine dioxide (ClO2); at the same time, due to the mechano-electrostatic coupling effect, hydroxyl radicals (·OH) and superoxide radicals (O2) can also be generated. ·- The removal of more than 90% of methyl violet by these active species, as verified in the above-mentioned examples, demonstrates the generation of chlorine dioxide (ClO2), hydroxyl radicals (·OH), and superoxide radicals (O2).·- Active species such as )

[0028] like Figure 1 As shown, piezoelectric catalysis and contact electrocatalysis can generate active species such as hydroxyl radicals and superoxide radicals, while ClO2 - A cycle that can participate in the above-mentioned piezoelectric catalysis and contact electrocatalysis processes is introduced.

[0029] Taking the piezoelectric effect as an example: Due to the piezoelectric polarization charge effect, a layer of positive and negative charges appears on the surface of the material. In order to achieve charge balance, a redox reaction is carried out on the surface of the material. The positive charge layer can react with hydroxide ions (OH-). - The electron transfer is completed, i.e., OH- - Losing electrons to form ·OH,ClO2 - After being added, it can also lose electrons and transform into ClO2. Meanwhile, because ClO2... - When dissolved in water, it forms a weakly alkaline solution, which also facilitates the formation of ·OH; and the negatively charged layer can transfer electrons with oxygen (O2), meaning that O2 loses electrons to form O2. ·- .

[0030] Taking the contact electrophoresis effect as an example: when the hydrophobic interface of the polymer comes into contact with and separates from the liquid, the liquid can carry away the charge of the hydrophobic interface layer of the polymer, that is, the charge separation and transfer are completed. Redox reactions are completed at different interfaces. Because it is an electron-withdrawing polymer, water molecules (H2O) will lose electrons and be transformed into water free radical cations (H2O). ·+ ), which is then converted into hydrated hydrogen ions (H3O) through the protonation effect. + ) and ·OH,ClO2 - Upon addition, it loses electrons and transforms into ClO2; while the polymer that gains electrons completes electron transfer with O2 to form O2. ·- .

[0031] For O2 ·- In general, HO2 can be formed through protonation. · Active species such as ClO2. - The addition of [the substance] enriches the electro-mechanical coupling catalytic reaction cycle.

[0032] In addition, it should be noted that H is introduced into the system. + Then, the space electrons in the transformation process can rely on H + As a carrier, H· is formed and participates in the system reaction, namely the proton-coupled electron transfer process, which can further facilitate the reaction of ClO2. - The conversion process with ClO2.

[0033] Therefore, catalytic activation of chlorite to produce chlorine dioxide, hydroxyl radicals and superoxide radicals can be used for pollutant removal. It also provides a new mechanical energy-derived chlorine dioxide preparation method, which broadens the preparation methods of chlorine dioxide. It can also be used for in-situ disinfection of microorganisms. At the same time, due to the relatively simple construction system, its future application scenarios are more extensive.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within the scope of its essence and protection. Such modifications or equivalent substitutions should also be considered to fall within the protection scope of the present invention.

Claims

1. A method for preparing chlorine dioxide by catalytic activation of chlorite, characterized in that, Driven by external force, polymers with piezoelectric, hydrophobic and electron-withdrawing properties are used as catalysts to catalyze the activation of chlorite to produce chlorine dioxide; The specific steps are as follows: After adding polymer powder material to water and mixing it thoroughly, chlorite is added and external force is activated to start the reaction to produce chlorine dioxide; The polymer is PVDF material, PTFE material, or a mixture of the two in any proportion; The external force drive is ultrasonic or ball mill drive.

2. The method for preparing chlorine dioxide by catalytic activation of chlorite according to claim 1, characterized in that: The ultrasonic frequency is ≥20kHz, and the ball mill rotation speed is ≥100rpm.

3. The method for preparing chlorine dioxide by catalytic activation of chlorite according to claim 1, characterized in that: The polymer powder has a particle size of 1~900μm and an addition amount of 10~1000mg / L.

4. The method for preparing chlorine dioxide by catalytic activation of chlorite according to claim 1, characterized in that: The concentration of the chlorite is 1 μmol / L to 10 mmol / L.

5. The method for preparing chlorine dioxide by catalytic activation of chlorite according to claim 1, characterized in that: After the polymer powder material was added to the water and thoroughly mixed, sulfuric acid with a concentration of 50 μmol / L was added.

6. The method for preparing chlorine dioxide by catalytic activation of chlorite according to claim 1, characterized in that: The ultrasonic or ball milling driving time is 30~240 min.

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