MO x -WO3 / SiO2 catalyst, its preparation method, and its application in desulfurization
By using rice husks as a silicon source and introducing MOx co-catalysts, MOx-WO3/SiO2 catalysts were prepared, solving the problems of expensive supports and poor removal efficiency. This achieved efficient and low-cost oxidative desulfurization, making it suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YANGTZE UNIVERSITY
- Filing Date
- 2023-09-25
- Publication Date
- 2026-07-24
AI Technical Summary
Existing WO3-based heterogeneous catalysts have expensive supports and poor oxidative removal efficiency for 4,6-DMDBT, which limits their industrial application.
Rice husks were used as the silicon source, and metal impurities were removed by acidification. MOx co-catalyst was combined with WO3 and SiO2 to prepare MOx-WO3/SiO2 catalyst. The interaction between MOx and WO3 and SiO2 was utilized to improve the dispersibility and stability of WO3 on the support.
It reduces catalyst costs, improves catalytic activity and stability, and is particularly suitable for the oxidative removal of DBT and 4,6-DMDBT. It also reduces WO3 loss and enhances the industrial application potential of the catalyst.
Smart Images
Figure CN117299110B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of desulfurization technology, specifically to an MO x -WO3 / SiO2 catalyst, its preparation method and its application in desulfurization. Background Technology
[0002] With increasing environmental awareness, various countries have successively promulgated strict standards for the sulfur content of fuel oil. Currently, hydrodesulfurization technology is mainly used in industry to remove organic sulfur compounds from fuel oil. It can efficiently remove mercaptans, sulfides, and disulfides, but this technology has drawbacks such as demanding operating conditions, high energy costs, and difficulty in removing thiophene sulfides, failing to meet the requirements for deep desulfurization of fuel oil. Therefore, it is essential to develop new desulfurization technologies to replace traditional hydrodesulfurization, such as oxidative desulfurization (ODS), adsorption desulfurization, and extraction desulfurization. Among these, ODS has received considerable attention due to its advantages, including mild reaction conditions, low operating costs, and effective removal of thiophene sulfides.
[0003] To achieve higher ODS efficiency, the development of excellent catalysts is a crucial breakthrough. Among the reported ODS catalysts, transition metal (Ti) catalysts are particularly important. 4+ V 5+ Mo 6+ W 6+Multiphase catalysts with oxides as active components have attracted much attention due to their high catalytic activity and stability. In particular, WO3-based multiphase catalysts have been reported many times in the application of oxidative desulfurization. For example, Li et al. (Transit.Met.Chem.2009,34(8):943-947) prepared WO3-SBA-15 by hydrothermal crystallization using H2WO4 as the tungsten source and tetraethyl orthosilicate as the silicon source. Under optimized reaction conditions and using a mixed solvent of 1-methyl-2-pyrrolidone and water as the extractant, this catalyst can reduce the sulfur content of gasoline from 540 to 46 ppm (desulfurization rate of 91.3%). Zhao et al. (Appl.Surf.Sci.2017,392,810-816) prepared WO3 / g-C3N4 composite material by mixing, grinding and calcining WO3 and g-C3N4 powders in a certain proportion. The composite material achieved a desulfurization rate of 91.2% in the oxidative desulfurization reaction of DBT simulated oil, and its activity did not decrease significantly after 5 cycles. Qin et al. (New J.Chem. 2017, 41(2): 569-578) prepared a WO3 / TiO2 catalyst by hydrothermal crystallization using octadecyltrimethylphosphotungsten ammonium ionic liquid as a template and tungsten source, and tetrabutyl titanate as a titanium source. The 550-WO3 / TiO2 sample achieved a desulfurization rate of 100% in the oxidative desulfurization reaction of DBT simulated oil, but the desulfurization rate decreased to 96.7% after 6 cycles. Unfortunately, the catalyst did not show high activity for the oxidative removal of 4,6-DMDBT. The above-mentioned WO3-based heterogeneous catalysts showed good oxidative removal effects on DBT, but poor effects on the oxidative removal of 4,6-DMDBT. In addition, the high cost of the support also limits the industrial application of WO3-based heterogeneous catalysts. Summary of the Invention
[0004] The technical problem to be solved by this invention is that the preparation of WO3-based heterogeneous catalysts involves the use of expensive supports, which limits the industrial application of WO3-based heterogeneous catalysts.
[0005] The first objective of this invention is to provide a MO x The preparation methods of WO3 / SiO2 catalysts include:
[0006] S1. Acidify the silicon-containing plant appendage powder to obtain pretreated silicon-containing plant appendage powder;
[0007] S2. Measure the silicon content in the pretreated silicon-containing plant appendage powder, and according to the mass ratio MO xWO3:SiO2 = 0.1~50:0.1~50:100 The co-catalyst, tungsten source, and pretreated silicon-containing plant appendage powder were mixed to obtain a mixture. The mixture was then subjected to aging, drying, and calcination in sequence at a calcination temperature of 550~750℃.
[0008] Alternatively, the co-catalyst and pretreated silicon-containing plant appendage powder are mixed and then subjected to a first aging, a first drying, and a first calcination at a temperature of 550–750°C to obtain a precursor. The precursor is then mixed with a tungsten source and subjected to a second aging, a second drying, and a second calcination at a temperature of 550–750°C to obtain the MO. x -WO3 / SiO2 catalyst;
[0009] Among them, the co-catalyst is MO x MO x It is derived from one or more water-soluble or alcohol-soluble compounds from Ce, Al, Zr, Fe, Mg, V, Zn, Sn, Ca, Li, Na, K, Mo, Co, and Mn.
[0010] When the above technical solution is adopted,
[0011] 1. Using pretreated silicon-containing plant appendage powder as a catalyst support and pore-forming agent, the raw materials are green, the preparation process is simple, and the conditions are easy to control, so the reproducibility is good and the raw material cost is low, which helps to reduce the cost of the catalyst and thus facilitates the industrial application of the catalyst.
[0012] 2.Introduce MO x As a cocatalyst, MO x It generates strong interactions with WO3 and SiO2, which is conducive to the high dispersion of WO3 on the support, inhibits the formation of WO3 crystals, and thus avoids the loss of WO3 in the ODS reaction, thereby improving catalytic activity.
[0013] 3. The MO prepared by this invention x -WO3 / SiO2 catalysts exhibited high catalytic oxidation activity and stability in the probe reaction simulation of fuel oil oxidative desulfurization reaction. Attached Figure Description
[0014] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:
[0015] Figure 1 MO of the present invention x XRD powder diffraction pattern of WO3 / SiO2 catalyst;
[0016] Figure 2 MO of the present invention x UV-Vis spectrum of WO3 / SiO2 catalyst;
[0017] Figure 3 MO of the present invention x -Linear plot of nitrogen adsorption-desorption isotherm of WO3 / SiO2 catalyst;
[0018] Figure 4 MO of the present invention x -BJH pore distribution diagram of WO3 / SiO2 catalyst. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.
[0020] Because the supports involved in existing WO3-based heterogeneous catalysts are expensive, their industrial applications are limited. Furthermore, some WO3-based heterogeneous catalysts have poor oxidative removal effects on 4,6-DMDBT. Therefore, there is an urgent need to develop a WO3-based heterogeneous catalyst that is cheaper and has better catalytic performance.
[0021] Rice husk (RH), the plant outer shell that wraps rice, is a porous agricultural waste rich in silicon (~20%). In recent years, the use of rice husk, with its high silicon content, as a catalyst support has attracted widespread attention. Shinde et al. (J. Chem. Technol. Biotechnol. 2003, 78.(12.), 1234-1238) used rice husk silica as a support and impregnated aqueous or organic solutions of FeCl3, SbCl3, BiCl3, and AlCl3 using an impregnation method to prepare supported metal chloride and metal oxide catalysts. Among them, the Sil–Fe-O-120 sample exhibited good catalytic activity and stability in the Friedel-Crafts benzylation reaction of monosubstituted aromatic hydrocarbons. Hindryawati et al. (Eng. Sci. Technol. Int. J. 2014, 17. (2.), 95-103) prepared alkali metal silicate solid base catalysts by impregnating aqueous solutions of LiOH, NaOH, and KOH with 200-mesh rice husks as a support. These catalysts exhibited high catalytic activity in the transesterification reaction of waste cooking oil and methanol, and the content of methyl ester compounds remained around 80% after six cycles of recycling. While the above studies achieved good results, the preparation of supported WO3-based catalysts using rice husks as a support and their application in oxidative desulfurization have not yet been reported.
[0022] In view of the above problems, the present invention provides an MO x The preparation method of the WO3 / SiO2 catalyst includes the following steps:
[0023] S1. Acidify the silicon-containing plant appendage powder to obtain pretreated silicon-containing plant appendage powder;
[0024] S2. Measure the silicon content in the pretreated silicon-containing plant appendage powder, and according to the mass ratio MO x WO3:SiO2 = 0.1~50:0.1~50:100 The co-catalyst, tungsten source, and pretreated silicon-containing plant appendage powder were mixed to obtain a mixture. The mixture was then subjected to aging, drying, and calcination in sequence at a calcination temperature of 550~750℃.
[0025] Alternatively, the co-catalyst and pretreated silicon-containing plant appendage powder are mixed and then subjected to a first aging, a first drying, and a first calcination to obtain a precursor. The precursor is then mixed with a tungsten source and subjected to a second aging, a second drying, and a second calcination to obtain the MO. x -WO3 / SiO2 catalyst.
[0026] In step S1, the purpose of the acidification treatment is mainly to remove metals or metal oxides from the silicon-containing plant appendage powder, making it suitable for use in subsequent steps. The acid used in the acidification process is a common strong acid in the art, such as dilute hydrochloric acid and dilute sulfuric acid. The concentration of the dilute hydrochloric acid can be 0.5 mol / L. The ratio of hydrogen ions in the strong acid to the dried silicon-containing plant appendage powder is 0.3 mol: 20-40 g; preferably 0.3 mol: 30 g.
[0027] In step S1, to ensure thorough acidification, the acidification process can be carried out at a certain temperature, such as around 50°C. The acidification time is generally around 24 hours. Stirring can be performed intermittently during the acidification process.
[0028] Silicon-containing plant byproduct powder can be obtained in the following ways:
[0029] The silicon-containing plant appendages are cleaned and dried. Cleaning mainly removes dirt and dust, while drying removes residual water. The drying temperature is generally around 50°C, and the drying time is approximately 48 hours. After drying, the appendages can be pulverized using common pulverizing equipment in this field. The resulting powder typically has a mesh size of around 200 mesh.
[0030] In step S1, the acidification treatment is followed by drying at a temperature of approximately 50°C. Then, a second drying process is carried out at a certain temperature until constant weight is achieved, at a temperature of approximately 110°C. Finally, the product is calcined at a temperature of approximately 600°C for a duration of approximately 5 hours.
[0031] In step S2, preferably, MO x WO3:SiO2 = 1.0–20: 5.0–25: 100; more preferably, MO x :WO3:SiO2=1.0~3.0:1.0~10.0:100.
[0032] The cocatalyst is derived from, but is not limited to, one or more water-soluble or alcohol-soluble compounds selected from Ce, Al, Zr, Fe, Mg, V, Zn, Sn, Ca, Li, Na, K, Mo, Co, and Mn.
[0033] The tungsten source includes, but is not limited to, water-soluble or alcohol-soluble tungsten-containing compounds, including at least one of phosphotungstic acid, silicotungstic acid, ammonium metatungstate, ammonium paratungstate, and sodium tungstate.
[0034] The mixing of the co-catalyst, tungsten source, and pretreated silicon-containing plant appendage powder can be specifically carried out by: first dissolving the co-catalyst and tungsten source in a solvent, then mixing them with the pretreated silicon-containing plant appendage powder, and finally stirring until homogeneous. The solvent can be water or an alcohol, and the alcohol includes, but is not limited to, at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, and 2-butanol.
[0035] In step S2, the aging can be carried out at room temperature, and the aging time is generally 24 to 72 hours, depending on the specific indoor temperature during operation.
[0036] In step S2, the drying temperature is generally 100-120℃, preferably 110℃, and the drying time is selected according to the specific drying temperature, generally 12-24h.
[0037] In step S2, the temperature during the roasting process is generally 550–750℃, for example: 550℃, 600℃, 620℃, 650℃, 680℃, 700℃, 750℃, and any value between the two, preferably 580–620℃. The roasting time is selected according to the specific temperature, generally around 5 hours.
[0038] Silicon sources are prepared using silicon-containing plant appendages, thereby reducing the cost of silicon sources. Adding a co-catalyst improves the dispersion of WO3 on the support and prevents the aggregation of WO3 crystals, which is beneficial for obtaining MO with good catalytic performance and stability. x -WO3 / SiO2 catalyst.
[0039] Example 1
[0040] Preparation of MO x -WO3 / SiO2 catalyst, including the following steps:
[0041] S1. Obtain silicon-containing rice husk powder
[0042] S1-1. Remove dirt and dust from the rice husks. Wash the rice husks with tap water, air dry them naturally, then dry them at 50℃ for 48 hours. Use a pulverizer to crush the rice husks and collect 100-200 mesh rice husk powder.
[0043] S1-2. Removal of metals and metal oxides from rice husks. The rice husks are treated by acidification. 30g of rice husks are placed in a 1L beaker, and 600mL of 0.5mol / L hydrochloric acid solution is added and stirred thoroughly. The mixture is then placed in a 50℃ water bath and kept warm for 24 hours, with intermittent stirring. After the end of the treatment, the mixture is filtered, washed until neutral, dried at 50℃, and ground into powder to obtain pretreated rice husk powder.
[0044] S1-3. Take the rice husks that need to be pretreated, dry them at 110℃ to constant weight, and then calcine them in a muffle furnace at 600℃ for 5 hours to obtain rice husks with a silicon content of 19.6%.
[0045] S2.MO x Preparation of WO3 / SiO2 catalyst
[0046] S2-1. The silicon-containing rice husk powder obtained in step S1 is placed in a 100mL beaker;
[0047] S2-2. Measure 9.5 mL of ethanol into a 50 mL beaker, then weigh 0.234 g of H3O. 40 PW 12 ·24H2O and 0.124g of Ce(NO3)3·6H2O were dissolved in an ethanol beaker by stirring to obtain a clear solution;
[0048] S2-3. Use a dropper to transfer the above clear solution into the rice husk powder, stirring constantly while adding, until an equal volume of impregnation is achieved;
[0049] S2-4. Aging at room temperature for 24 hours, drying at 110℃ for 8 hours, grinding, and calcining at 600℃ for 5 hours yielded a 2.5% CeO2-10% WO3 / SiO2 catalyst.
[0050] It should be noted that in the 2.5% CeO2-10% WO3 / SiO2 catalyst, 2.5% = CeO2 / SiO2 (mass ratio) and 10% = WO3 / SiO2 (mass ratio).
[0051] Example 2
[0052] This embodiment prepares a 1.25% MgO-10% WO3 / SiO2 catalyst according to Example 1, except that the co-catalyst is MgO and magnesium acetate tetrahydrate is the magnesium source.
[0053] Example 3
[0054] This embodiment prepares a 1.0% Fe2O3-10% WO3 / SiO2 catalyst according to Example 1, except that the co-catalyst is Fe2O3 and the iron source is ferric nitrate nonahydrate.
[0055] Example 4
[0056] This embodiment prepares a 1.8% ZnO-10% WO3 / SiO2 catalyst according to Example 1, except that the co-catalyst is ZnO and zinc acetate dihydrate is the zinc source.
[0057] Example 5
[0058] This embodiment uses a multiple impregnation method to prepare a 3.5% TiO2-10% WO3 / SiO2 catalyst. First, 10.0 g of treated rice husk powder was weighed into a 100 mL beaker. Then, 9.5 mL of ethanol was measured into a 50 mL beaker, followed by 0.300 g of tetrabutyl titanate, which was stirred and dissolved to obtain a clear solution. The ethanol solution of the metal salt was then added to the rice husk powder dropwise while stirring continuously until an equal volume impregnation state was achieved. The mixture was aged at room temperature for 24 h, dried at 110 °C for 8 h, ground, and calcined at 600 °C for 5 h to obtain a 3.5% TiO2 / SiO2 precursor. Similarly, using a 3.5% TiO2 / SiO2 precursor as a support and phosphotungstic acid hydrate as a tungsten source, a second impregnation was performed using the above method. The catalyst was aged at room temperature for 24 hours, dried at 110°C for 8 hours, ground, and calcined at 600°C for 5 hours to obtain a 3.5% TiO2-10% WO3 / SiO2 catalyst.
[0059] It should be noted that in the 3.5% TiO2-10% WO3 / SiO2 catalyst, 3.5% = CeO2 / SiO2 (mass ratio) and 10% = WO3 / SiO2 (mass ratio).
[0060] Example 6
[0061] This embodiment prepares a 1.0% V2O5-10% WO3 / SiO2 catalyst according to Example 5, except that the co-catalyst is V2O5, ammonium metavanadate is the vanadium source, water is the solvent, and oxalic acid is the co-solvent for ammonium metavanadate.
[0062] Example 7
[0063] This embodiment prepares a 20% ZrO2-10% WO3 / SiO2 catalyst according to Example 5, except that the co-catalyst is ZrO2, the zirconium pentahydrate is the zirconium source, and the solvent is water.
[0064] Example 8
[0065] This embodiment prepares a 20% Al2O3-10% WO3 / SiO2 catalyst according to Example 5, except that the co-catalyst is Al2O3, the aluminum source is aluminum nitrate nonahydrate, and the solvent is water.
[0066] Example 9
[0067] This embodiment prepares a 10% TiO2-5.0% WO3 / SiO2 catalyst according to Example 5. The difference is that the titanium source is titanium acetylacetone, the solvent for supporting titanium acetylacetone is isopropanol, the tungsten source is ammonium metatungstate, and the solvent for supporting ammonium metatungstate is isopropanol.
[0068] Example 10
[0069] This embodiment prepares a 10% TiO2-25% WO3 / SiO2 catalyst according to Example 5, except that the titanium source is titanium tetrachloride, the solvent for loading titanium acetylacetone is methanol, the tungsten source is sodium tungstate, and the solvent for loading ammonium metatungstate is water.
[0070] Comparative Example 1
[0071] This comparative example was prepared according to Example 1, except that no cerium source was added during the preparation process, and the resulting catalyst was a 10% WO3 / SiO2 catalyst.
[0072] Comparative Example 2
[0073] Take 3.0g H3O 40 PW 12 ·24H2O was placed in an evaporating dish and calcined at 600℃ for 5 hours to obtain WO3.
[0074] Comparative Example 3
[0075] Take 5.0g of pretreated rice husks, dry them at 110℃ to constant weight, and then calcine them in a muffle furnace at 600℃ for 5h to obtain SiO2 from the rice husks.
[0076] Example 11
[0077] This embodiment illustrates the effect of the MOx-WO3 / SiO2 catalyst obtained by the method of the present invention on the catalytic oxidation of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT).
[0078] DBT and 4,6-DMDBT were dissolved in n-octane to prepare simulated oils; the sulfur concentrations in the DBT and 4,6-DMDBT simulated oils were 1000 and 500 ppm, respectively. The catalyst (0.100 g) prepared in the examples or comparative examples, 10 mL of simulated oil, and 10 mL of acetonitrile were sequentially added to a 50 mL two-necked flask connected to a condenser, and heated to 70 °C. Then, hydrogen peroxide (n(H₂O₂) / n(S) = 12) was added to initiate the reaction (DBT reaction for 1 h, 4,6-DMDBT reaction for 2 h). Finally, the reaction mixture was cooled and centrifuged. The supernatant was analyzed by GC 126N (FPD detector, HP-5 capillary column), and the residual DBT and 4,6-DMDBT in the simulated oil were quantified using peak area normalization. The conversion rates of DBT and 4,6-DMDBT were defined as the amount of sulfide reacted divided by the initial amount of sulfide. The results are shown in Table 1.
[0079] Table 1. Pore structure parameters and oxidative desulfurization performance of catalysts prepared in each example and comparative example.
[0080]
[0081] As shown in Table 1, the present invention uses rice husk as a silicon source, and the resulting catalyst has good catalytic desulfurization performance, and is particularly suitable for the removal of DBT and 4,6-DMDBT.
[0082] Example 12
[0083] This embodiment examines the catalytic stability of the catalyst obtained in Example 11. After the reaction, acetonitrile was used as a solvent to separate and recover the catalyst. The catalyst was dried and calcined at 550°C for 2 hours to obtain the regenerated catalyst. The desulfurization reaction in Example 11 was repeated using the regenerated catalyst sample.
[0084] The catalyst obtained in Comparative Example 1 maintained a DBT conversion rate of over 98.0% and a 4,6-DMDBT conversion rate of over 99.0% after 7 cycles (see Table 2). ICP-OES tests were performed on the catalysts in Comparative Example 1 and after 7 cycles. The results showed that the WO3 / SiO2 mass ratio in the 10% WO3 / SiO2 catalyst was 9.3%. After 8 cycles in the ODS reaction of DBT simulated oil, the WO3 / SiO2 mass ratio was 1.5%, and after 9 cycles in the ODS reaction of 4,6-DMDBT simulated oil, the WO3 / SiO2 mass ratio was 1.8%. This indicates that WO3 was significantly lost (over 80%) during the 7 cycles.
[0085] The catalyst obtained in Example 5 maintained a conversion rate of over 99.0% for DBT and 4,6-DMDBT after 11 cycles, as shown in Table 2. ICP-OES tests were performed on the catalyst from Example 5 and the catalyst after cycles. The results showed that the mass ratios of WO3 / SiO2 and TiO2 / SiO2 in the 3.5% TiO2-10% WO3 / SiO2 catalyst were 9.3% and 3.3%, respectively. After 11 cycles in the ODS reaction of DBT and 4,6-DMDBT simulated oil, the mass ratios of WO3 / SiO2 in the catalyst were 8.2% and 8.1%, respectively. After 11 cycles in the ODS reaction of DBT and 4,6-DMDBT simulated oil, the mass ratios of TiO2 / SiO2 in the catalyst were 3.0% and 3.1%, respectively.
[0086] Compared with Comparative Example 1 and Example 5, the introduction of TiO2 into the 10% WO3 / SiO2 sample resulted in a favorable strong interaction between TiO2 and WO3 and SiO2, which allowed WO3 to be highly dispersed on the support, inhibited the formation of WO3 crystals, greatly suppressed the loss of WO3 active sites, and enhanced the catalytic stability of the catalyst.
[0087] Table 2 shows the desulfurization rates of the catalyst samples obtained in Comparative Examples 1 and 5 after repeated experimental testing.
[0088]
[0089] The XRD powder diffraction patterns of the catalysts obtained in Examples 1-8 and Comparative Examples 1-2 are as follows: Figure 1 As shown, by Figure 1 It can be seen that the catalyst samples obtained in Comparative Examples 1 and 2 all exhibited diffraction peaks at 2θ angles of 23.1°, 23.6°, 24.4°, 28.9°, 41.9°, and 55.9°, corresponding to the (002), (020), (200), (112), (222), and (420) crystal planes of monoclinic WO3, respectively. Based on WO3 / SiO2, the peak intensities of the samples decreased to some extent after doping with CeO2, MgO, Fe2O3, TiO2, and V2O5 co-catalysts; after doping with ZnO, monoclinic ZnWO4 was formed; after doping with ZrO2 co-catalyst, cubic ZrO2 was formed without the characteristic diffraction peaks of WO3, indicating that WO3 exhibited a highly dispersed state on the support; after doping with Al2O3 co-catalyst, the sample exhibited an amorphous structure, indicating that WO3 exhibited a highly dispersed state on the support. The above results indicate that doping with a co-catalyst reduces the crystallinity of WO3, resulting in a highly dispersed state of WO3 on the support. This is beneficial for increasing the active sites of WO3, enhancing the catalytic oxidation activity of the catalyst, and simultaneously inhibiting the loss of WO3 active sites during the oxidative desulfurization reaction.
[0090] The UV-Vis spectra of the catalysts obtained in Examples 1-8 and Comparative Examples 1-2 are as follows: Figure 2 As shown, by Figure 2 It can be seen that the WO3 sample obtained in Comparative Example 2 shows absorption peaks at 246 nm and 372 nm, which can be attributed to octahedral WO3 samples, respectively. 6+ Species and WO3 crystals. Furthermore, the WO3 sample exhibits a considerable absorption tail in the visible and near-infrared regions, indicating abundant oxygen vacancies. Using rice husk as the silicon source, WO3 was loaded to obtain the sample of Comparative Example 1, which produced an absorption peak at 220 nm, attributed to tetrahedral WO3. 6+ Species. Furthermore, the absorption tails disappeared in the sample, and the octahedral W... 6+ The peak intensity of the species increases, while the peak intensity of WO3 crystal decreases significantly. After doping with CeO2, MgO, Fe2O3, TiO2, V2O5, ZnO, Al2O3, and ZrO2 cocatalysts, the peak intensity of WO3 crystal generally shows a decreasing trend, with the tetrahedral WO3 showing a decreasing trend. 6+ And the octahedral W 6+The peak intensities of the species showed varying degrees of increasing trends. In particular, after doping with TiO2 and ZrO2 co-catalysts, the octahedral W... 6+ The species showed the greatest increase in peak intensity. It is generally believed that different forms of W... 6+ The activity level of species in catalytic oxidative desulfurization is as follows: The W octahedral species... 6+ Species > Tetrahedral W 6+ Species > WO3 crystals. These results indicate that doping with metal oxide co-catalysts on the basis of WO3 / SiO2 promotes a favorable and strong interaction between the co-catalyst and WO3 and SiO2, allowing WO3 to be highly dispersed on the support, inhibiting the formation of WO3 crystals, and increasing the number of octahedral W atoms. 6+ The number of active sites of the species can be increased to improve the catalytic activity of the catalyst sample, while avoiding the loss of WO3 in the oxidative desulfurization reaction.
[0091] The products obtained in Examples 3, 5, 7 and Comparative Example 3 were characterized by nitrogen adsorption-desorption isotherms, and the results are as follows: Figure 3 and 4 As shown. By Figure 3 and 4 It can be seen that all samples exhibit typical Type IV isotherms in the IUPAC classification, with a significant hysteresis loop appearing when the relative pressure P / P0 > 0.4, indicating that the samples have macroporous or mesoporous pores. Furthermore, the mesopores in the samples are concentrated in the 2-80 nm range, with the most probable pore size being 3.7 nm. Compared with the WO3 sample obtained in Comparative Example 2 (see Table 1), the catalyst samples obtained in Comparative Example 1 and Examples 1-10 all have larger specific surface area, external surface area, and mesopore volume. This is beneficial for reactant molecules with larger kinetic sizes (such as DBT and 4,6-DMDBT) to approach the active sites and overcome diffusion effects.
[0092] In summary, the present invention has the following beneficial effects:
[0093] 1. Using silicon-containing plant appendage powder as a catalyst support and pore-forming agent, the raw materials are green, the preparation process is simple, and the conditions are easy to control, so the reproducibility is good and the raw material cost is low, which helps to reduce the cost of the catalyst and thus facilitates the industrial application of the catalyst.
[0094] 2.Introduce MO x As a cocatalyst, MO x It generates strong interactions with WO3 and SiO2, which is conducive to the high dispersion of WO3 on the support, inhibits the formation of WO3 crystals, and thus avoids the loss of WO3 in the ODS reaction, thereby improving catalytic activity.
[0095] 3. The MO prepared by this invention x-WO3 / SiO2 catalysts exhibited high catalytic oxidation activity and stability in the probe reaction simulation of fuel oil oxidative desulfurization reaction.
[0096] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A kind of MO x The method for preparing the WO3 / SiO2 catalyst is characterized by, The preparation method includes: The silicon-containing plant appendage powder was acidified to obtain pretreated silicon-containing plant appendage powder. The silicon content in the pretreated silicon-containing plant appendage powder was measured, and the content was determined according to the mass ratio MO. x WO3:SiO2 = 1.0~20:5.0~25:100 The co-catalyst, tungsten source, and pretreated silicon-containing plant appendage powder were mixed to obtain a mixture. The mixture was then subjected to aging, drying, and calcination in sequence at a calcination temperature of 550~750℃. or; The co-catalyst and pretreated silicon-containing plant byproduct powder were mixed and then subjected to a first aging, a first drying, and a first calcination at a temperature of 550–750°C to obtain a precursor. The precursor was then mixed with a tungsten source and subjected to a second aging, a second drying, and a second calcination at a temperature of 550–750°C to obtain the MO. x -WO3 / SiO2 catalyst; Among them, the co-catalyst is MO x MO x Derived from one or more water-soluble or alcohol-soluble compounds from Ce, Al, Zr, Fe, Mg, V, and Zn; The acidification treatment is achieved using a strong acid, wherein the ratio of hydrogen ions in the strong acid to the dried silicon-containing plant appendage powder is 0.3 mol: 30 g. The acidification treatment is carried out at 40–60°C in a water bath. The acidification treatment is followed by two drying and calcination treatments. The temperature of the first drying treatment is 40-60℃, the temperature of the second drying treatment is 100-120℃, and the temperature of the calcination treatment is 550-650℃. The source of the co-catalyst and the tungsten source are first dissolved in a solvent and then mixed with the pretreated silicon-containing plant appendage powder; or; The source of the catalyst is dissolved in a solvent and mixed with pretreated silicon-containing plant appendage powder. The mixture undergoes a first aging, a first drying, and a first calcination at a temperature of 550–750°C to obtain a precursor. The precursor is then mixed with a dissolved tungsten source solution. The temperature for both the first and second drying processes is 100–120°C, and the drying time is 12–24 hours.
2. The MO according to claim 1 x The method for preparing the WO3 / SiO2 catalyst is characterized by, The first and second aging processes were both carried out at room temperature, with an aging time of 24–72 hours.
3. A method for preparing MO according to any one of claims 1-2 x -WO3 / SiO2 catalyst, characterized in that The MO x The pore size of the WO3 / SiO2 catalyst is 3.2–4.0 nm, and the specific surface area is 200–300 m². 2 / g, mesoporous surface area is 200-300m² 2 / g, mesoporous pore volume is 0.20-0.40cm³ 3 / g.
4. A MO as described in claim 3 x - Application of WO3 / SiO2 catalyst in desulfurization.