Active carbon particle loaded tungsten trioxide and titanium dioxide composite photocatalyst and preparation method thereof

Abstract

The invention discloses a preparation method of an activated carbon particle loaded tungsten trioxide and titanium dioxide composite photocatalyst, which comprises the following steps: mixing a tungsten source precursor and a titanium salt precursor, dissolving an organic acid (such as citric acid) in deionized water, adding activated carbon particles, introducing an inorganic acid, fully stirring and dispersing, placing in a reaction kettle at 220 DEG C for 24 hours, standing to room temperature, filtering, washing, and drying to obtain the activated carbon particle loaded tungsten trioxide and titanium dioxide composite photocatalyst. And carrying out ethanol-water alternate cleaning to remove impurities so as to obtain light yellow solid particles. The adsorption performance of the activated carbon particles is effectively combined with the composite photocatalytic activity of tungsten trioxide and titanium dioxide to generate synergy, the forbidden band width of titanium dioxide is generally 3.0-3.2 eV, the forbidden band width of tungsten trioxide (WO3) is about 2.7 eV, and effective compensation can be formed between titanium dioxide and tungsten trioxide (WO3). The utilization efficiency of a catalytic medium is effectively improved, so that the method has a very good application prospect in the fields of photocatalysis of VOCs and degradation of dye wastewater.

Description

Technical Field

[0001] The present invention relates to a tungsten trioxide and titanium dioxide composite photocatalyst, in particular to an activated carbon particle-loaded tungsten trioxide and titanium dioxide composite photocatalyst and a preparation method thereof, and belongs to the fields of composite material science and photocatalysis. Background Art

[0002] In recent decades, increasing industrialization has led to environmental pollution, particularly air and water pollution. Typical treatment methods for industrial wastewater and waste gas include physicochemical, biochemical, chemical, and a combination of these processes. In recent years, the development of semiconductor photocatalytic technology has provided a highly efficient energy resource. Naturally, the development of highly effective photocatalysts is a key development direction in this field. Currently, TiO2 is a widely used photocatalytic material. Its unique semiconductor structure imparts high catalytic activity, enabling efficient degradation of difficult-to-degrade organic pollutants in diverse environments. It also offers advantages such as being non-toxic, pollution-free, and highly stable. However, pure nano-TiO2 also has drawbacks, including a wide bandgap, low quantum efficiency, and fine particles that easily agglomerate and are difficult to recycle.

[0003] Tungsten trioxide (WO3) is a unique N-type semiconductor material with a wide light absorption band, high photostability, low price, and easy preparation. It has become a widely studied semiconductor catalytic material after TiO2, and has demonstrated excellent catalytic performance in pollutant treatment, making it a very promising photocatalyst. However, hexagonal tungsten trioxide nanomaterials used in the photocatalytic degradation of organic matter have a wide band gap and low quantum efficiency, resulting in low utilization of sunlight. Summary of the Invention

[0004] The present invention aims to provide a method for preparing a composite photocatalyst of tungsten trioxide and titanium dioxide loaded on activated carbon particles, so as to improve the photocatalytic activity of the composite photocatalyst of tungsten trioxide and titanium dioxide.

[0005] 1. Preparation of activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst This invention discloses a method for preparing a tungsten trioxide and titanium dioxide composite photocatalyst loaded on activated carbon particles. The method involves mixing a tungsten source and a titanium salt in a 1:1 molar ratio, dissolving the mixture in deionized water with an organic acid (such as citric acid) to form a homogeneous solution. Cylindrical activated carbon particles measuring 2 mm x 3 mm in diameter are added, their high specific surface area enhancing the loading of active components. An inorganic acid (such as hydrochloric acid or sulfuric acid) is introduced to adjust the pH to 1-3 to promote the hydrolysis-polycondensation reaction. After thorough stirring and uniform dispersion, the mixture is placed in a 220°C reactor for 24 hours to achieve in-situ growth of WO3 / TiO2, forming a stable crystalline composite oxide under high temperature and pressure. The mixture is then allowed to cool to room temperature, washed with alternating ethanol and water to remove impurities, and dried at low temperature to prevent crystal agglomeration. This results in light yellow solid particles. The invention utilizes a reactor to load tungsten trioxide and titanium dioxide onto the surface of the activated carbon particles in situ. The activated carbon's microporous structure (with a specific surface area of ​​500-1700 m2 / g) enriches pollutants and shortens the mass transfer distance of reactive oxygen species (·OH). Oxygen-containing functional groups (-COOH, -OH) on the carbon surface act as anchoring sites, inhibiting the shedding of nanoparticles (approximately 10-20 nm). This effectively combines the adsorption properties of the activated carbon particles with the combined photocatalytic activity of tungsten trioxide and titanium dioxide, creating a synergistic effect. WO3 (2.7 eV) and TiO2 (3.2 eV) form a type II heterojunction, broadening the visible light response range (400-450 nm) and improving the efficiency of photogenerated electron-hole separation. This significantly enhances the composite photocatalyst's performance in the degradation of organic pollutants. Since the band gap of titanium dioxide is generally 3.0 to 3.2 eV, and that of tungsten trioxide (WO3) is approximately 2.7 eV, the two complement each other effectively. This effectively improves the utilization efficiency of the catalytic medium, thus holding great promise for photocatalytic VOC degradation and dye wastewater degradation.

[0006] The preparation method of the activated carbon particle-loaded activated carbon particle-loaded tungsten trioxide and titanium dioxide composite photocatalyst of the present invention comprises the following steps: dissolving a tungsten source precursor and a titanium salt precursor organic acid in deionized water, sequentially adding an inorganic acid solution and activated carbon particles thereto, fully stirring to uniformly disperse the activated carbon particles, then transferring the mixed solution to a hydrothermal synthesis reactor, sealing the reactor, controlling the temperature at 220° C. to perform a hydrothermal reaction for 24 hours, cooling to room temperature, washing the product with ethanol and deionized water in sequence to obtain a dark brown wet product, and drying to obtain light yellow solid particles, which are the activated carbon particle-loaded tungsten trioxide and titanium dioxide composite photocatalyst.

[0007] The tungsten source precursor is sodium tungstate dihydrate or anhydrous sodium tungstate. The titanium salt precursor includes isopropyl titanate and tetrabutyl titanate.

[0008] In the activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst prepared above, the loading amount of tungsten trioxide and titanium dioxide is 20-35%.

[0009] Activated carbon particles have a well-developed porous structure and a specific surface area of ​​500-1700 m2 / g. The activated carbon particles are loaded with tungsten trioxide and titanium dioxide photocatalysts, a typical activated carbon particle morphology. Tungsten trioxide and titanium dioxide nanohexagons are loaded on the porous and multi-slit surface of the activated carbon particles. This structure of nanohexagons loaded on a multi-porous and multi-slit surface exhibits both adsorption and photocatalytic properties, potentially creating a synergistic effect.

[0010] 2. Photodegradation performance test of activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst To test the photocatalytic activity of a composite photocatalyst supported on activated carbon particles with tungsten trioxide and titanium dioxide, methylene blue (MB) was selected as a representative refractory organic pollutant for photocatalytic degradation. Five grams of the composite photocatalyst supported on activated carbon particles with tungsten trioxide and titanium dioxide were dispersed in 50 mL of a 20 mg / L methylene blue solution. The reaction was allowed to proceed in the dark for 20 minutes to reach adsorption-desorption equilibrium. Subsequently, the reaction was allowed to proceed in a photocatalytic reactor for one hour. The residual MB concentration was determined by UV-visible spectrophotometry, and the decolorization efficiency was calculated.

[0011] Results showed that the activated carbon particles-loaded tungsten trioxide (TGO) achieved a 68% removal rate of methylene blue after a 20-minute dark reaction, demonstrating the adsorption capacity of the activated carbon particles-loaded tungsten trioxide and titanium dioxide composite photocatalyst for methylene blue. When the electrodeless lamp was activated, photocatalytic degradation played a primary role. After one hour of illumination, the activated carbon particles-loaded tungsten trioxide and titanium dioxide composite photocatalyst achieved a 99.88% removal rate of methylene blue, demonstrating the excellent catalytic degradation performance of the activated carbon particles-loaded tungsten trioxide and titanium dioxide composite photocatalyst for methylene blue. The degradation reaction was a synergistic effect of adsorption by the activated carbon particles and photocatalytic degradation by the TGO and titanium dioxide composite photocatalyst.

[0012] The visible light degradation rate of methylene blue (20 mg / L) can reach 99.88% / h, which is three times higher than that of pure Tio2‌.

[0013] After 100 cycles, the activity remains at 90%, indicating good stability.

[0014] Suitable for gas phase degradation of toluene (VOCs) (removal rate > 90%) and antibiotic wastewater treatment.

[0015] In summary, the present invention uses activated carbon particles as a carrier and in situ loads tungsten trioxide and titanium dioxide onto the surface of the activated carbon particles via a one-pot hydrothermal method to produce an activated carbon particle-loaded tungsten trioxide and titanium dioxide composite photocatalyst. This effectively combines the adsorption properties of the activated carbon particles with the photocatalytic activity of tungsten trioxide and titanium dioxide, creating a synergistic effect that significantly enhances the photocatalytic degradation performance of the photocatalyst for organic pollutants. This effectively increases the utilization efficiency of the loaded tungsten trioxide and titanium dioxide composite photocatalyst. Therefore, it has promising application prospects in the field of photocatalytic degradation of dye wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the final physical diagram of the present invention. DETAILED DESCRIPTION

[0017] The preparation and photocatalytic performance of the activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst of the present invention are further described below through specific examples.

[0018] Tungsten trioxide and titanium dioxide were in situ loaded onto the surface of activated carbon particles using a hydrothermal method: First, 0.5–3.5 g of a tungsten precursor, 0.5–3.5 g of a titanium salt precursor, and 0.3–3.3 g of an organic acid were dissolved in 30–150 mL of deionized water. Subsequently, 10–100 mL of an inorganic acid solution was slowly added dropwise. 1.5–5.0 g of activated carbon particles were then added and stirred thoroughly to ensure uniform mixing of the activated carbon particles and the solution. The mixture was then transferred to a sealed hydrothermal synthesis reactor and incubated at 150–200°C for 12–24 hours to allow for full reaction. Third, the reactor was cooled naturally to room temperature, and the sample was removed and rinsed three to six times with ethanol and then deionized water, yielding a dark brown solid sample. Finally, the sample was vacuum-dried at 50–100°C for 5–10 hours to obtain a light yellow solid particle, which is the activated carbon particle-loaded tungsten trioxide and titanium dioxide composite photocatalyst. Example 1

[0019] 3.5 g of sodium tungstate dihydrate, 3.5 g of tetrabutyl titanate, and 3.0 g of citric acid were dissolved in 80 mL of deionized water. 100 mL of hydrochloric acid solution (concentration of 3.5 mol / L) was then slowly added dropwise. After stirring evenly, 4.8 g of activated carbon particles were added and stirred to uniformly mix the activated carbon particles with the solution. The mixture was then transferred to a hydrothermal synthesis reactor, which was sealed and kept at 220°C for 24 h. After the reaction was completed, it was naturally cooled to room temperature, taken out and washed five times with ethanol and deionized water in sequence to obtain a dark brown granular solid sample. Finally, the solid sample was vacuum dried at 90°C for 6 h to obtain light yellow solid particles, which are activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst. Example 2

[0020] 4.5 g of anhydrous sodium tungstate, 4.5 g of isopropyl titanate, and 4.0 g of edible acid were dissolved in 90 mL of deionized water. 500 mL of hydrochloric acid solution (1.5 mol / L) was then slowly added dropwise. After stirring evenly, 9.5 g of activated carbon particles were added and stirred thoroughly to evenly disperse the activated carbon particles. The mixture was then transferred to a hydrothermal synthesis reactor, which was sealed and kept at 220°C for 24 h. After the reaction was completed, it was naturally cooled to room temperature. The sample was removed and washed three times with ethanol and deionized water to obtain a dark brown, sticky solid sample. Finally, the solid sample was vacuum dried at 90°C for 6 h to obtain light yellow solid particles, which were the activated carbon particles-loaded tungsten trioxide and titanium dioxide composite photocatalyst.

[0021] The activated carbon particles are loaded with tungsten trioxide and titanium dioxide composite photocatalysts. Using a 300W electrodeless lamp at 253.7nm, the photodegradation of 20mg / m³ formaldehyde in 0.5h can achieve a formaldehyde removal rate of 99%.

[0022] In the above embodiments, the activated carbon particles have a particle size of Φ2mm×L3mm.

Claims

1. The preparation method of activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst is as follows: tungsten source precursor and titanium salt precursor organic acid are dissolved in deionized water, inorganic acid solution and activated carbon particles are added thereto in sequence, and the activated carbon particles are fully stirred to uniformly disperse the activated carbon particles. The mixed solution is then transferred to a hydrothermal synthesis reactor, and the reactor is sealed. The temperature is controlled to be 220°C for hydrothermal reaction for 24 hours, and the mixture is allowed to cool to room temperature. The product is washed with ethanol and deionized water in sequence, and dried in a drying chamber to obtain light yellow solid particles, which are activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst.

2. The method for preparing the activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst according to claim 1, characterized in that: The tungsten source precursor is sodium tungstate dihydrate or anhydrous sodium tungstate, and the titanium salt precursor includes isopropyl titanate and tetrabutyl titanate.

3. The method for preparing the activated carbon particle tungsten trioxide and titanium dioxide composite photocatalyst according to claim 1, characterized in that: The organic acid refers to citric acid or tartaric acid.

4. The method for preparing the activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst according to claim 3, characterized in that: The mass ratio of the tungsten source precursor to the organic acid is 1:0.6~1:1.2, and the mass ratio of the titanium salt precursor to the organic acid is 1:0.6~1:1.

2.

5. The method for preparing the activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst according to claim 1, characterized in that: The inorganic acid is hydrochloric acid, and its concentration is 0.6-4.9 mol / L.

6. The method for preparing the activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst according to claim 5, characterized in that: The molar ratio of the tungsten source precursor to the inorganic acid is 1:0.5-1:1.8, and the molar ratio of the titanium salt precursor to the inorganic acid is 1:0.5-1:1.

8.

7. The method for preparing the activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst according to claim 1, characterized in that: The particle size of the activated carbon particles is Φ2mm×L3mm.

8. The method for preparing the activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst according to claim 1, characterized in that: The mass ratio of the tungsten source precursor to the granular activated carbon is 1:2.8~1:5.8, and the mass ratio of the titanium salt precursor to the granular activated carbon is 1:2.8~1:5.

8.

9. The method for preparing the activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst according to claim 1, characterized in that: The drying is performed at 50° C. to 100° C. in vacuum for 5 h to 10 h.

10. The activated carbon particles loaded with tungsten trioxide and titanium dioxide composite photocatalyst prepared by the method of claim 1, characterized in that: The content ratio of tungsten trioxide and titanium dioxide on activated carbon is 20~35%.

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