Copper oxide-silicon dioxide composite material as well as preparation method and application thereof

Abstract

The invention relates to a preparation method of a copper oxide-silicon dioxide composite material, which comprises the following steps: (a) mixing choline chloride and copper salt to obtain a mixed material; (b) mixing tetraethoxysilane or a solution containing tetraethoxysilane with the mixed material in the step (a); and (c) stirring, drying and roasting the material obtained in the step (b) to obtain the final copper oxide-silicon dioxide composite material. The composite material provided by the invention is used for adsorbing methyl orange in wastewater, and has the advantages of high adsorption capacity, good regeneration performance and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of water pollution control, and in particular relates to a copper oxide-silicon dioxide composite material and a preparation method and application thereof. Background Art

[0002] Adsorption is an efficient method for treating dye pollutants in water. The development of efficient and durable adsorbents is an important factor affecting the application of adsorption. Silica has a large specific surface area and good stability and is widely used in wastewater adsorption treatment. However, the adsorbent needs to be replaced after adsorption saturation, which is time-consuming, labor-intensive, and costly. By loading a catalyst on the adsorbent to synthesize a composite material, the adsorption performance of the adsorbent can be restored through a catalytic oxidation regeneration process after adsorption saturation, allowing the adsorbent to be recycled, which is more economical and environmentally friendly. Copper oxide is an important transition metal oxide with unique electrical, magnetic, and catalytic properties. The synthesis of copper oxide-silica composite materials has become a research hotspot.

[0003] CN105642286A discloses a method for preparing a nano-copper oxide mesoporous silica core-shell structure material. First, nano-copper oxide core particles are synthesized by thermal decomposition. These nano-copper oxide core particles and an alkyl silicate are added to a mother liquor. The resulting nano-copper oxide mesoporous silica core-shell structure material is then washed, filtered, dried, and calcined. The resulting material exhibits excellent thermal stability and dispersibility.

[0004] CN103007941A discloses a method for preparing a catalyst for the selective hydrogenation of furfural to furfuryl alcohol. The catalyst is a copper oxide-silicon oxide composite oxide. The preparation process includes: adding water to copper salt, stirring and dissolving it, and reacting it with a 10%-20wt% sodium hydroxide solution to form colloid A; diluting the silica colloidal body with twice its weight of water to form colloid B; adding colloid B to colloid A, and sequentially heating, aging, filtering, washing, drying, and calcining the mixed colloid; and finally hydrogenating and reducing it for 3-18 hours to produce the catalyst.

[0005] CN103480382A discloses a catalyst for producing 1,4-butynediol and a method for its preparation. This method uses acidified nano-silica as a carrier, adsorbing copper and bismuth onto the carrier through impregnation and precipitation, resulting in a catalyst containing 35% to 65% copper oxide by weight. The addition of silica sol also makes the catalyst more stable and wear-resistant. The resulting catalyst exhibits excellent activity, high selectivity, and strength, is less prone to pulverization during use, and maintains high activity.

[0006] CN108404867A discloses a lignin-based carbon magnetic nanomaterial, its preparation method, and its application in methyl orange adsorption. The process includes the following steps: dissolving ferrous sulfate and ferric chloride in water, preheating, dropwise adding ammonia and hydrogen peroxide, and aging at 70-90°C for 1-3 hours; adding a lignin solution and a short-chain alcohol to the system, stirring at this temperature for 1-3 hours; separating and drying; and carbonizing at 500-650°C under an inert atmosphere for 3-4 hours, cooling, and pulverizing to obtain the lignin-based carbon magnetic nanomaterial. This invention uses lignin as a carbon source and combines high-temperature carbonization and high-temperature reforming to produce a lignin-based carbon magnetic nanomaterial with the advantages of uniform particle size, high carbon loading, and strong methyl orange adsorption capacity, making it suitable for methyl orange adsorption.

[0007] Methyl orange is an azo dye with high toxicity and difficulty in biochemical treatment. Therefore, effectively removing methyl orange from water is a major challenge in treating printing and dyeing wastewater. Existing copper oxide-silicon dioxide composites used for adsorbing methyl orange-containing wastewater suffer from low adsorption capacity and poor regeneration performance. Summary of the Invention

[0008] In response to the shortcomings of the prior art, the present invention provides a copper oxide-silicon dioxide composite material, a preparation method thereof, and applications thereof. The composite material provided by the present invention is used to adsorb methyl orange in wastewater and has the advantages of high adsorption capacity and good regeneration performance.

[0009] A first aspect of the present invention provides a method for preparing a copper oxide-silicon dioxide composite material, the method comprising the following steps:

[0010] (a) mixing choline chloride and copper salt to obtain a mixed material;

[0011] (b) mixing ethyl orthosilicate or a solution containing ethyl orthosilicate with the mixed material of step (a);

[0012] (c) The material obtained in step (b) is stirred, dried, and calcined to obtain the final copper oxide-silicon dioxide composite material.

[0013] Furthermore, the copper salt in step (a) is at least one of copper nitrate trihydrate, copper chloride dihydrate, and the like.

[0014] Furthermore, the molar ratio of choline chloride to copper salt in step (a) is 1:1-2.

[0015] Furthermore, the mixing temperature of the choline chloride and copper salt in step (a) is 65-95° C., preferably 75-85° C. The mixing can be carried out under stirring conditions. There are no particular requirements for the stirring method and stirring speed, as long as the choline chloride and copper salt are fully mixed. The stirring time is generally 20-80 minutes, preferably 30-60 minutes.

[0016] Furthermore, the ethyl orthosilicate in step (b) is a commercially available product. The solution containing ethyl orthosilicate is an aqueous solution containing ethyl orthosilicate, wherein the mass fraction of ethyl orthosilicate is 69%-77%.

[0017] Furthermore, the mass ratio of the ethyl orthosilicate or the solution containing ethyl orthosilicate in step (b) to the mixed material in step (a) is 2-5:1 based on the mass of ethyl orthosilicate.

[0018] Furthermore, the mixing of the ethyl orthosilicate or the solution containing ethyl orthosilicate in step (b) with the material obtained in step (a) can be carried out under stirring conditions at room temperature, above room temperature, or below room temperature, preferably at a mixing temperature of 20-40°C, more preferably 25-30°C.

[0019] Furthermore, in step (b), ethyl orthosilicate or a solution containing ethyl orthosilicate is added to the mixed material in step (a). The addition process can be all at once or dropwise. The dropwise addition is generally 30-90 drops per minute.

[0020] Furthermore, the stirring time in step (c) is 22-26 hours.

[0021] Furthermore, in step (c), the drying temperature is 100-150° C., preferably 128-132° C., and the drying time is 1-7 h, preferably 4.5-5.5 h.

[0022] Furthermore, in step (c), the calcination temperature is 350-650° C., preferably 450-550° C., and the calcination time is 0.5-4 h, preferably 1.5-2.5 h.

[0023] A second aspect of the present invention provides a copper oxide-silicon dioxide composite material prepared using the method of the present invention. The copper oxide content is 10% to 30% by weight, based on the total weight of the composite material; and the silicon dioxide has a particle size of less than 80 nm.

[0024] The third aspect of the present invention is to provide a copper oxide-silicon dioxide composite material prepared by the above method for use as an adsorbent in treating wastewater containing methyl orange.

[0025] Furthermore, in the application of the present invention, the mass content of methyl orange in the methyl orange-containing wastewater is 1%-3% based on the weight of the methyl orange-containing wastewater, the treatment temperature is 20-30° C., and the treatment time is 20-60 minutes, preferably 30-50 minutes.

[0026] Furthermore, in the application described in the present invention, the regeneration conditions of the copper oxide-silicon dioxide composite material after adsorption saturation are as follows: regeneration is carried out in an oxygen-containing atmosphere, for example, in an air atmosphere; the regeneration temperature is 250-450°C, preferably 300-400°C, and the regeneration time is 20-60 minutes, preferably 30-50 minutes.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) A mixture of choline chloride and copper salt is used as a copper source and then interacts with ethyl orthosilicate. The quaternary ammonium salt in the reaction system may react with the unsaturated residual bonds and silanol groups in different bonding states on the surface of nano-silica, so that quaternary amino groups exist on the surface or in the pores of silica, which is beneficial to improve the adsorption performance of methyl orange through the interaction between the quaternary amino groups and the sulfonic acid groups in methyl orange.

[0029] (2) Choline chloride and copper salt are first mixed, and then ethyl orthosilicate is added, so that silicon and copper form oxides simultaneously. The surface contains many coordinated unsaturated atoms and has a high surface energy. This special coordination environment and binding energy may cause a strong interaction between silicon dioxide and copper oxide, which not only improves the dispersibility of the synthesized copper oxide, but also facilitates the formation of coordination bonds with methyl orange, while improving the adsorption and catalytic properties.

[0030] (3) The copper oxide-silicon dioxide composite material is used as an adsorbent to adsorb wastewater containing methyl orange. It has the advantages of large adsorption capacity, easy regeneration through catalytic oxidation, restoration of adsorption performance of the adsorbent, increase in the number of recycling times, and improvement of the adsorbent service life. DETAILED DESCRIPTION

[0031] The technical solution of the present invention and its effects are further described in detail below with reference to specific examples. The examples are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following examples.

[0032] The experimental methods in the following examples, unless otherwise specified, are conventional methods in the art. The experimental materials used in Example 1 below, unless otherwise specified, were purchased from a conventional biochemical reagent store. In the context of the present invention, unless otherwise specified, % is by mass.

[0033] Example 1

[0034] (a) Choline chloride and copper nitrate trihydrate were stirred and mixed at 80° C. for 30 minutes to form a mixed material, wherein the molar ratio of choline chloride to copper nitrate trihydrate was 1:1.

[0035] (b) Add ethyl orthosilicate to distilled water and stir to prepare a solution containing ethyl orthosilicate, wherein the mass fraction of ethyl orthosilicate is 69%.

[0036] (c) adding the solution from step (b) to the mixture from step (a) at a mass ratio of 2:1 based on the mass of ethyl orthosilicate in the solution to the mixture from step (a); stirring at room temperature for 24 h, drying at 130° C. for 5 h, and calcining at 400° C. for 2 h to obtain a copper oxide-silicon dioxide composite material.

[0037] Example 2

[0038] (a) Choline chloride and copper nitrate trihydrate were stirred and mixed at 70° C. for 60 minutes to form a mixed material, wherein the molar ratio of choline chloride to copper nitrate trihydrate was 1:1.

[0039] (b) Add ethyl orthosilicate to distilled water and stir to prepare a solution containing ethyl orthosilicate, wherein the mass fraction of ethyl orthosilicate is 77%.

[0040] (c) adding the solution from step (b) to the mixture from step (a) at a mass ratio of 2:1 based on the mass of ethyl orthosilicate in the solution to the mixture from step (a); stirring at room temperature for 24 h, drying at 145 ° C. for 3 h, and calcining at 600 ° C. for 1.5 h to obtain a copper oxide-silicon dioxide composite material.

[0041] Example 3

[0042] (a) Choline chloride and copper nitrate trihydrate were stirred and mixed at 85° C. for 20 minutes to form a mixture, wherein the molar ratio of choline chloride to copper nitrate trihydrate was 1:1.5.

[0043] (b) Add ethyl orthosilicate to distilled water and stir to prepare a solution containing ethyl orthosilicate, wherein the mass fraction of ethyl orthosilicate is 73%.

[0044] (c) adding the solution from step (b) to the mixture from step (a) at a mass ratio of 2:1 based on the mass of ethyl orthosilicate in the solution to the mixture from step (a); stirring at room temperature for 24 h, drying at 120° C. for 6 h, and calcining at 500° C. for 2 h to obtain a copper oxide-silicon dioxide composite material.

[0045] Example 4

[0046] The preparation process and conditions in this embodiment are basically the same as those in Example 1, except that the mass ratio of the mixture in step (c) to that in step (a) is 4:1 based on the mass of ethyl orthosilicate in the solution. Other reaction conditions and preparation process remain unchanged, thereby obtaining a copper oxide-silicon dioxide composite material.

[0047] Example 5

[0048] The preparation process and conditions in this embodiment are basically the same as those in Example 1, except that in step (a), choline chloride and copper nitrate trihydrate are mixed at a molar ratio of 1:2. Other reaction conditions and preparation process remain unchanged, thereby obtaining a copper oxide-silicon dioxide composite material.

[0049] Example 6

[0050] The preparation process and conditions in this embodiment are basically the same as those in Example 1, except that copper chloride dihydrate is used as the copper salt, and a copper oxide-silicon dioxide composite material is finally prepared.

[0051] Example 7

[0052] The preparation process and conditions in this example are basically the same as those in Example 1, except that the aqueous solution of ethyl orthosilicate is added dropwise to the mixed material in step (a) at a rate of 60 drops per minute to finally obtain a copper oxide-silicon dioxide composite material.

[0053] Comparative Example 1

[0054] The same as Example 1, except that: 0.72 g of copper nitrate trihydrate and sodium hydroxide were added to 12.4 mL of distilled water and stirred to form a copper nitrate solution, 13.4 mL of ethyl orthosilicate was added to the copper nitrate solution and stirred at room temperature for 24 hours, then dried at 130°C for 5 hours, and calcined at 400°C for 2 hours to finally obtain a copper oxide-silicon dioxide composite material.

[0055] Comparative Example 2

[0056] The method is the same as Example 1, except that 1-ethyl-3-methylimidazole chloride is used instead of choline chloride to finally prepare a copper oxide-silicon dioxide composite material.

[0057] Comparative Example 3

[0058] The same as Example 1, except that: in step (1), there is no mixing process of choline chloride and copper nitrate trihydrate, and copper nitrate trihydrate is directly mixed with ethyl orthosilicate solution, with the same feeding amount, to finally prepare a copper oxide-silicon dioxide composite material.

[0059] Comparative Example 4

[0060] The same as Example 1, except that: in step (1), ferric nitrate nonahydrate is used instead of copper nitrate trihydrate, and the feeding amount is the same, and finally a ferric oxide-silicon dioxide composite material is prepared.

[0061] Test Case

[0062] The static adsorption method was used to evaluate the performance of different materials in treating methyl orange in water.

[0063] The concentration of the methyl orange solution to be treated was 30 mg / L. The adsorbent materials prepared in Examples 1-7 and Comparative Examples 1-4 were added at a mass ratio of adsorbent material to methyl orange in the solution of 1:30. The mixture was continuously shaken at 160 rpm at 25° C. for 30 minutes to reach adsorption equilibrium. After centrifugation, the supernatant was collected and the absorbance was measured at 465 nm using an ultraviolet spectrophotometer (UNICOWFZ UV-2000). The methyl orange removal rate of the material in water was calculated as follows:

[0064]

[0065] Where H is the removal rate of methyl orange, A0 and A e are the absorbance of methyl orange solution before and after treatment, respectively.

[0066] After adsorption saturation, the material was collected by centrifugation and heated in a tube furnace at 350° C. for 30 minutes at 30 mL / min in an air atmosphere for regeneration.

[0067] Table 1 Static adsorption results and regeneration effects

[0068] Material Methyl orange removal rate H Removal rate after 5 cycles H Example 1 88.4％ 78.2％ Example 2 86.6％ 77.3％ Example 3 84.3％ 78.1％ Example 4 87.1％ 70.5％ Example 5 85.8％ 77.6％ Example 6 79.2％ 75.4％ Example 7 87.4％ 76.9％ Comparative Example 1 54.0％ 22.1％ Comparative Example 2 57.5％ 23,6％ Comparative Example 3 53.1％ 20.4％ Comparative Example 4 49.3％ 29.1％

Claims

1. A method for preparing a copper oxide-silicon dioxide composite material, characterized in that The following steps are involved: (a) mixing choline chloride and copper salt to obtain a mixed material; (b) mixing ethyl orthosilicate or a solution containing ethyl orthosilicate with the mixed material in step (a); and (c) stirring, drying, and calcining the material obtained in step (b) to obtain a final copper oxide-silicon dioxide composite material.

2. The method according to claim 1, wherein: The copper salt in step (a) is at least one of copper nitrate trihydrate and copper chloride dihydrate.

3. The method according to claim 1 or 2, characterized in that: The molar ratio of choline chloride to copper salt in step (a) is 1:1-2.

4. The method according to claim 1, wherein: In step (a), the mixing temperature of choline chloride and copper salt is 65-95° C., preferably 75-85° C.; and the stirring time is 20-80 minutes, preferably 30-60 minutes.

5. The method according to claim 1, wherein: The solution containing ethyl orthosilicate in step (b) is an aqueous solution containing ethyl orthosilicate, wherein the mass fraction of ethyl orthosilicate is 69%-77%.

6. The method according to claim 1 or 5, wherein: The mass ratio of the ethyl orthosilicate or the solution containing ethyl orthosilicate in step (b) to the mixed material in step (a) is 2-5:1 based on the mass of ethyl orthosilicate.

7. The method according to claim 1, wherein: In step (b), the ethyl orthosilicate or the solution containing ethyl orthosilicate is mixed with the material obtained in step (a) under stirring conditions. The mixing temperature is 20-40°C, preferably 25-30°C.

8. The method according to claim 1, wherein: Step (b) adding ethyl orthosilicate or a solution containing ethyl orthosilicate to the mixed material of step (a), the adding process is one-time or dropwise, and the dropwise addition is 30-90 drops per minute.

9. The method according to claim 1, wherein: The stirring time in step (c) is 22-26 hours.

10. The method according to claim 1, wherein: The drying temperature in step (c) is 100-150° C., preferably 128-132° C., and the drying time is 1-7 h, preferably 4.5-5.5 h.

11. The method according to claim 1, wherein: The calcination temperature in step (c) is 350-650° C., preferably 450-550° C., and the calcination time is 0.5-4 h, preferably 1.5-2.5 h.

12. A copper oxide-silicon dioxide composite material, characterized in that The copper oxide-silicon dioxide composite material is prepared by the method according to any one of claims 1 to 11.

13. Use of the copper oxide-silicon dioxide composite material prepared by the method according to any one of claims 1 to 11 or according to claim 12 as an adsorbent in treating wastewater containing methyl orange.

14. The use according to claim 13, characterized in that: The mass content of methyl orange in the methyl orange-containing wastewater is 1%-3% based on the weight of the methyl orange-containing wastewater, the treatment temperature is 20-30° C., and the treatment time is 20-60 minutes, preferably 30-50 minutes.

15. The use according to claim 13 or 14, characterized in that: The regeneration conditions of the copper oxide-silicon dioxide composite material after adsorption saturation are as follows: regeneration is carried out in an oxygen-containing atmosphere, for example, in an air atmosphere; the regeneration temperature is 250-450° C., preferably 300-400° C., and the regeneration time is 20-60 minutes, preferably 30-50 minutes.

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