A visible light-driven photo catalyst for removing sulfur-containing compounds in fuel oil, a preparation method thereof and application thereof

Visible light catalyst for removing sulfur compounds in fuel oil and its preparation and application technical field

[0001] The present invention relates to the removal of sulfur-containing compounds such as phene and its derivatives in fuel, and specifically to a dual-agent supported photocatalyst and its preparation method and application. A catalyst for the visible light-catalyzed oxidation reaction of sulfur-containing compounds such as benzothiophene and dibenzothiophene.

Background technique

[0002] The SO' generated after the combustion of sulfur-containing compounds in fuel not only causes many harms to the environment such as acid rain, but also is a type of sulfur-containing compounds that are difficult to remove. At present, in industry, the traditional hydrodesulfurization method is one of the main ways to reduce the sulfur content in fuel oil. However, due to problems such as high operating costs and complex equipment, there is an urgent need to develop new high-efficiency and low-cost non-hydrodesulfurization technologies. Oxidative desulfurization is considered to be one of the very promising ultra-deep desulfurization technologies due to its mild operating conditions (normal temperature, normal pressure) and no hydrogen consumption; while photocatalytic oxidative desulfurization uses molecular oxygen as the oxidant (does not use hydrogen peroxide) , The operating conditions are mild, so it is a potentially cheap and environmentally friendly desulfurization technology, which has attracted the attention of the industry.

[0003] F. Berthou et al. (F. Berthou and V. Vignier, Int., J. Environ. Chem.,

1986, 27, 81.) Try to use direct sunlight to desulfurize, dissolve dibenzophene in natural seawater filtered by membrane, leave it in sunlight for 8 days, the removal rate can reach 80%. However, the reaction time of this process is too long to be of practical significance. Yasuhiro Shiraishi et al. A (Yasuhiro Shiraishi et al., Ind. Eng. Chem. Res. 1996, 35, 586; Yasuhiro Shiraishi et al., Chem. Commun., 1998, 2601; Yasuhiro Shiraishi et al., Ind. Eng. Chem. Res·, 1999, 38, 310; Yasuhiro Shiraishi et al., Ind. Eng. Chem. Res. 2000, 39₇ 1345; Yasuhiro Shiraishi et al., Journal of Chemical Engineering of

Japan, 2002, 35, 489.) A series of attempts have been made in the photosensitivity conversion experiment of dibenzophene. The photosensitizer used ranges from the first benzophenone to the efficient dioxon onion (DCA), and the solvent is also changed from The initial tetradecane is transferred to acetonitrile, which is a relatively stable aprotic polar solvent, and the sulfur content in the raw material liquid can be reduced from 1800 ppm to 100 ppm in 2 hours. Zhao Jincai et al., Incai Zhao et al., J. Phys. Chem. B, 2006, 110, 2942.) Using 2-(4-methoxyphenyl) -4, 6-diphenylpyrylium as photosensitizer, p-dibenzophene and dimethyl Photocatalytic desulfurization of the ethyl dibenzophene-based ethyl cyanine solution can convert 190 ppm of sulfur in the raw material liquid to nearly 100% within 8 hours. The product is mainly sub-inkstone and inkstone. However, these processes require the use of photosensitizers, which cause difficulties in separation and recovery and cause certain pollution to oil products.

[0004] Since the efficiency of pure photocatalysis is not high and the oxidation capacity is limited, people continue to develop other means of assisting the photocatalysis process. Yusufg et al. (Yusufg et al., Environ. Sci. Technol., 2005, 39, 8557.) reported on Ti. ?As a photocatalyst, 3% H₂0₂ (aq) The process of oxidizing dibenzophene and 4,6-dimethyldibenzophene into the corresponding sub-inkstone and inkstone with the aid of ultrasonic waves as an oxidant. Naiqiang Yan et al. (Naiqiang Yan et al., Energy & Fuels, 2006, 20, 142; Naiqiang Yan et al., Journal of Chemical Industry and Engineering (China), 2003, 54, 1279) also reported the use of Y-ray irradiation as Auxiliary means of oxidation process.

[0005] It is not difficult to find from the reported work that the existing catalysts for photocatalytic oxidation of sulfur-containing organic molecules have the following deficiencies: (1) The activity of the catalyst needs to be further improved; (2) The use of photosensitizers makes Separation and recovery are difficult, causing certain pollution to the desulfurization product; (3) Other auxiliary means are required, and the operation cost is high. Therefore, it is very necessary to open

A photocatalytic oxidative desulfurization catalyst with high activity, environmentally friendly and easy to recycle with visible light response is developed.

Summary of the invention

[0006] The object of the present invention is to provide a highly active, environmentally friendly, easy to recycle photocatalytic oxidation catalyst for the removal of sulfur-containing compounds such as phene and its derivatives in fuel oil and its preparation method and application.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: a visible light catalyst for removing sulfur compounds in fuel, the catalyst is composed of a metal M, a metal dish, and BiV.₄The carrier composition, where the metal M_:And metal Μ_πThe sum of mass (Μ_:+Μ_π) And BiV0₄The mass ratio of the carrier is 1:5000-1:50; metal M_:And metal Μ_πThe mass ratio is 1:50-50:1; wherein the metal Μ [selected from one of Pt, Pd, Au, the metal Μ_πOne selected from Ru and Ir.

[0008] The preparation method of the photocatalyst includes the following steps: a) First, BiV0 is prepared.₄Carrier: Dissolve button salt and organic salt in a molar ratio of Bi / V = 1: 0.5-1: 2 into 2 mol · L nitric acid to make Bi ion and V ion concentrations both 0.05-0.5 mol · Γ¹After forming a uniform clear solution, adjust the pH value of the solution to 1-3 with ammonia water, and transfer it to a hydrothermal reaction kettle lined with polytetrafluoroethylene at 100-250 °C for 12 h-48 h; After obtaining the flocculent precipitate, centrifugation, washing, drying, and finally calcining the obtained powder at 50-200 °C overnight in an air environment; b) Impregnating the above-mentioned BiV04 carrier in the metal-containing M_πIn the aqueous solution of the soluble salt, the photocatalyst precursor is obtained by stirring and evaporating the water and calcining to obtain the photocatalyst precursor, which is dissolved in a mixed solution composed of water and methanol in a volume ratio of 3:2-4:1 to form a catalyst precursor slurry; c) Combining the slurry of the catalyst precursor with the metal-containing M_:The aqueous solution of the soluble salt is mixed, and the photoreduction deposition reaction is carried out under light.

[0009] Wherein step c) the metal Μ_:The concentration of the soluble salt in the aqueous solution is 0.1-0.5 mg M_:/mL, step b) the metal Μ_πThe concentration of the soluble salt in the aqueous solution is 0.5-1.5 mg M_n/mL_o

[0010] Wherein, in step b), the stirring and evaporation is carried out at 50-90°C for 3-6 hours, and the roasting is carried out at 100-500°C in air atmosphere for 0.5-4 hours.

[0011] Wherein the photoreduction deposition reaction in step c) is performed at room temperature with a fluorite lamp (wavelength 420nm <λ <700 nm) for 1-4 hours.

[0012] The photocatalyst can be used in a photocatalytic oxidative desulfurization process containing sulfur-containing compounds, and the operation steps are as follows: The sulfur-containing compounds are phenanthrene, benzophene, dibenzophene, and the like.

[0013] Add 10 mg-100 mg of the catalyst to 50 ml of the above-mentioned sulfur-containing compound solution, pass in O?, stir the reaction for 30-240 min under visible light irradiation at 10 Ό-20 ° C, stop the reaction, and separate Recover the catalyst.

[0014] Visible light is irradiated by a fern lamp, with a wavelength of 420nm <λ <700 nm.

[00Compared with the known technology, the present invention has the following advantages:

1. The invention designs and synthesizes a dual-agent supported photocatalyst with ultra-low metal loading, prepares a photocatalyst with higher activity with visible light response, is environmentally friendly, has high stability, and can be recycled. [0016] 2. The present invention uses cheap oxygen as an oxidant, no environmental pollution, and at the same time reduces the cost of the reaction.

[0017] 3. The catalyst is used in the visible light catalytic oxidative desulfurization of sulfur-containing compounds in fuel oil. It exhibits high desulfurization activity. Under mild operating conditions (room temperature, 1 atm), oxygen is used as the oxidant. The light source (devil lamp, wavelength 420nm <λ <700 nm), avoids the absorption of light by the oil (mainly concentrated in the ultraviolet region), and is not excited in the oil

At the same time, the removal rate of phenosulfur can reach more than 90%.

[0018] 4. The sulfur in the oil can be oxidized to SO3 and escaped from the reaction system to be absorbed by the absorption liquid, which avoids the extraction and removal steps in the traditional process and reduces the operating cost. Compared with the ultraviolet photocatalyst, it can be used in a wide range of oil products. After the reaction, the catalyst can be recovered by standing or centrifugal separation.

Description of the drawings

[0019] FIG. 1 is a SEM photograph of the catalyst prepared in Example 1 of the present invention. It can be seen from Figure 1 that the catalyst particle size is about 2 μm.

[0020] FIG. 2 a) is the ultraviolet-visible diffuse reflectance spectrum of the catalyst prepared in Example 1. It can be seen from the figure that the absorption edge of the prepared catalyst can reach 530 nm; Figure 2 b) is the UV-visible diffuse reflectance spectrum of the actual oil product. It can be seen from the figure that the absorption edge of diesel and gasoline can reach 420 nm . Therefore, under the illumination of visible light source, it is ensured that the catalyst can absorb the energy of light and play the role of photocatalytic oxidation while the oil is not excited.

[0021] FIG. 3 is an XRD spectrum of the fresh catalyst prepared in Example 14 and the reacted catalyst. It can be seen from Figure 3 that the prepared catalyst is monoclinic BiV0₄, The structure is stable during the reaction, and the monoclinic phase structure is still well maintained after the reaction.

4 is an XRD spectrum of the white precipitate obtained in Example 16. It can be seen from the figure that the XRD spectrum of the white precipitate and BaS0₄The standard spectra of is very good, indicating that during the reaction, sulfur can be oxidized to S0₃And escape from the reaction system.

Detailed ways

[0023] In order to further illustrate the present invention, the following implementation examples are listed, but it does not limit the scope of the invention defined by the appended claims.

[0024] Example 1 B1VO₄Preparation: The button salt and organic salt are dissolved in nitric acid according to the ratio of Bi / V = 1: 1 to produce Bi ion and V ion concentration of 0.1 mol · Γ¹The solution. After forming a uniform clear solution, adjust the pH value of the solution to 2.2 with ammonia water and transfer it to a hydrothermal reaction kettle lined with polytetrafluoroethylene at 200 °C for hydrothermal reaction for 24 hours. After obtaining the flocculent precipitate, centrifugation, washing, drying, and finally roasting the obtained powder at 90 °C overnight in an air environment.

[0025] The BiVO prepared above₄The catalyst performs photocatalytic oxidative desulfurization experiments on the solution containing phene: (1) Take 50 ml of phene solution containing 600 ppm of sulfur in the photoreactor, add 0.050 g of catalyst A, and then pass oxygen at 10 °C , Stir vigorously under 1 MPa and light for 3 h; (2) Centrifugal separation of the above treatment solution to recover the catalyst, the sulfur content can be detected in the GC-FPD, and the removal rate is 4 & 8%.

[0026] Example 2 Preparation of the catalyst in the present invention.

[0027] Weigh 0.05 g of ferric chloride dissolved in 100 ml of water, and stir for 30 min; weigh 1.0 g of BiVOp prepared in Example 1 and add 5 mL of the above mixed solution, sonicate for 1 h, and let stand for 24 h; Heat in a water bath at 50 °C to remove moisture, calcined at 300 °C for 1 h to obtain a catalyst precursor; disperse the obtained catalyst precursor in a mixed solution of water and methanol with a volume ratio of 4:1 to form a catalyst To the precursor slurry, add 1 mL of a chloric acid aqueous solution with a concentration of 0.3578 mg Pt/mL, stir and mix vigorously, pass in high-purity nitrogen for 30 min, illuminate for 1 h, and finally filter, wash with deionized water, and dry in vacuo. yellow

The colored solid catalyst is called Catalyst A.

[0028] Example 3 Use chlorinated nails (0.42 g) dissolved in 100 mL of water, take 0.5 mL of the solution, and the remaining steps are the same as in Example 2, called catalyst B.

[0029] Example 4 Use chlorinated nails (0.42 g) dissolved in 100 mL of water, take 0.05 mL of the solution, and the remaining steps are the same as in Example 2, called catalyst Co

[0030] Example 5 A photocatalytic oxidative desulfurization experiment was carried out on a model system of a sulfur compound containing sulfur: (1) 50 mL of a sulfur containing 600 ppm sulfur solution was placed in a photoreactor, and 0. 100 g catalyst A was added, Oxygen was then introduced, 10 °C, 1 MPa under vigorous stirring and illumination for 3 h; (2) Centrifugal separation of the above-mentioned treatment solution to recover the catalyst, the sulfur content can be detected in the GC-FPD, and the removal rate is 92.3%.

[0031] Example 6 Catalyst B was selected, and the amount added was 0.100 g, the reaction pressure was 1 MPa, and the remaining operating conditions were the same as in Example 5. The application results were tested in GC-FPD, and the removal rate was 95.3%.

[0032] Example 7 Catalyst C was selected, and the amount added was 0.100 g, the reaction pressure was 1 MPa, and the remaining operating conditions were the same as in Example 5. As a result of the application, the sulfur removal rate detected in the GC-FPD was 93.8%.

[0033] Example 8 Preparation of another catalyst in the present invention.

[0034] Weigh 0.42 g of chlorinated nails dissolved in 100 mL of water and stir for 30 min; Weigh 1.0 g BiV0₄, Add 0.05 mL of the above mixed solution, ultrasonic for 1 h, let stand for 24 h; heat to remove water in a water bath at 50 °C, calcined at 300 Ό for 1 h to obtain a catalyst precursor; disperse the obtained catalyst precursor in the volume The catalyst precursor slurry is formed in a mixed solution of water and methanol with a ratio of 4:1, and 1 mL of a chlorinated rake aqueous solution with a concentration of 0.37 mg Pd/mL is added, stirred and mixed vigorously, and high-purity nitrogen is introduced for 30 min. Light for 1 h, finally filtered, washed with deionized water, and dried in vacuum to obtain a yellow solid catalyst, called Catalyst D.

[0035] Example 9 A chloroauric acid (1.196 mg Au/mL) aqueous solution was used, and 0.17 mL was dropped into the photoreduction deposition experiment, and the remaining operation steps were the same as in Example 8, which was called catalyst E.

[0036] Example 10 Use chloric acid (0.3578 mg Pt/mL) aqueous solution, take 0.56 mL dropwise to carry out the photoreduction deposition experiment, the rest of the operation steps are the same as in Example 8, called catalyst F.

[0037] Example 11 Use chloric acid (0.3578 mg Pt /mL) aqueous solution, take 0.84 mL dropwise to carry out the photoreduction deposition experiment, the rest of the operation steps are the same as in Example 8, called the catalyst Go

[0038] Example 12 The above-mentioned catalyst was carried out on the photocatalytic oxidative desulfurization experiment of a sulfide model system containing phene: (1) Take 50 mL of a phene solution containing 600 ppm of sulfur in a photoreactor, and add 0.10 g catalyst D, re-entry

Oxygen, 10 °C, vigorous stirring under 1 MPa light for 3 h; (2) Centrifugal separation of the above-mentioned treatment solution to recover the catalyst, the sulfur content can be detected in the GC-FPD, and the removal rate is 90.0%.

[0039] Example 13 Catalyst E was selected, and the amount added was 0.100 g, and the remaining operating conditions were the same as in Example 12. The application results were detected in GC-FPD, and the removal rate was 90.1%.

[0040] Example 14 Catalyst F was selected, and its addition was 0.050 g, and the remaining operating conditions were the same as in Example 12. The application result was detected in GC-FPD, and the removal rate was 91.5%.

[0041] Example 15 uses catalyst G, and its addition is 0.050 g, and the remaining operating conditions are the same as in Example 12. The application result was detected in GC-FPD, and the removal rate was 99.4% ο

[0042] Example 16 The gas generated in the reaction system in Example 15 was absorbed with NaOH (0.2 Μ), and Ba(N0₃)₂And HN0₃(aq), a white precipitate which is insoluble in nitric acid is obtained.

[0043] In all the above embodiments, all the catalysts can be reused.

[0044] In summary, the present invention prepares a dual-agent supported photocatalyst with higher photocatalytic activity with visible light response. The catalyst is used for the photocatalytic oxidative desulfurization of fuel containing sulfur compounds such as phene middle. Under mild operating conditions (room temperature, 1 atm), oxygen is used as the oxidant, and a visible light source is used (refractory lamp, wavelength 420nm <λ <700 nm), which avoids the absorption of light by oil (mainly concentrated in the ultraviolet region) ), while the oil product is not excited, the removal rate of phenosulfur can reach more than 90%, and the sulfur in the oil product can be oxidized to S0₃It escapes from the reaction system and is absorbed by the absorption liquid, which avoids the extraction and removal step in the traditional process. Compared with ultraviolet light catalysts, a wide range of oils can be used. After the reaction, the catalyst can be recovered by standing or centrifugal separation. This dual co-catalyst greatly improves the separation and transport ability of electron holes in the carrier, thereby obtaining a highly active photocatalyst. Under mild operating conditions, through photocatalytic desulfurization reaction, it is very good for phene-containing sulfur compounds. The removal effect of the catalyst, and the use of oxygen as the oxidant reduces the cost of the reaction. At the same time, the catalyst is easy to be recycled and reused.