A method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials

Abstract

The present application relates to the field of metal cyanide preparation, and more specifically to a method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials. The present invention uses g-C3N4 and zinc powder as raw materials and adopts vacuum sealing and sintering technology to prepare the material. The specific steps include: mixing g-C3N4 and zinc powder evenly and then loading them into a quartz tube, evacuating the quartz tube, sealing the quartz tube, placing the quartz tube in a muffle furnace and keeping it warm for a period of time, cooling it, and collecting the product in the quartz tube, i.e., zinc cyanide nanomaterial. Due to the advantages of the non-toxicity and short reaction time of the zinc cyanide nanomaterial prepared by the present invention, the present invention has good application prospects in the field of zinc cyanide nanomaterial preparation technology.

Description

Technical Field

[0001] The present application relates to the field of metal cyanide preparation, and in particular to a method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials. Background Art

[0002] Zinc cyanide has a variety of uses, such as pesticides, metallurgy, electronics, etc. For example: Chinese patent CN99112474.X, a method for gold extraction by full-mud zinc cyanide powder replacement and carbon slurry adsorption in series; Chinese patent CN201920626391.6, an electronic-grade zinc cyanide mixing device for PCB processing, both involve the application of zinc cyanide.

[0003] Since zinc cyanide is a highly toxic chemical, the precursors required for its preparation are generally also highly toxic, so its synthesis is greatly restricted.

[0004] Previous synthesis methods often use zinc sulfate and sodium cyanide as raw materials. For example, as described in Chinese Patent CN104291356A, zinc sulfate and sodium cyanide are dissolved separately, mixed, and precipitated to produce zinc cyanide. The mixture is then filtered, rinsed with water, dehydrated, and dried to obtain the product. Zinc cyanide can be obtained by reacting zinc acetate and acetone cyanohydrin as precursors in a solution for two days. Zinc cyanide can also be obtained by reacting zinc nitrate and potassium zinc cyanide as precursors for two to three weeks. Zinc cyanide nanomaterials can also be prepared using a vapor phase method: a zinc cyanide precursor (e.g., zinc cyanide powder) is mixed with an appropriate vapor-phase carrier gas (typically nitrogen or argon) and reacted in a high-temperature chamber. Under high-temperature conditions, the vapor-phase precursor begins to decompose, releasing zinc cyanide atoms or molecules. These zinc cyanide atoms or molecules recombine in the vapor phase to form nanoparticles. The resulting zinc cyanide nanoparticles in the vapor phase are then quenched or cooled to condense into solid particles. However, the above methods all require the use of highly toxic cyanide as a raw material, or the reaction time is long and the preparation efficiency is low. Summary of the Invention

[0005] The present invention addresses the shortcomings of the prior art by providing a method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials. The present invention not only uses non-toxic raw materials but also shortens the reaction time, providing a rapid and green method for preparing zinc cyanide. The prepared zinc cyanide is a nanoscale material, and the morphology of the zinc cyanide product can be controlled by varying the temperature.

[0006] The invention provides a method for synthesizing zinc cyanide nanomaterials by using non-toxic raw materials. The zinc cyanide nanomaterials are prepared by using g-C3N4 and zinc powder as raw materials and adopting vacuum sealing sintering technology.

[0007] The specific technical solutions adopted are as follows:

[0008] Mix g-C3N4 and zinc powder evenly and put them into a quartz tube;

[0009] Evacuate the quartz tube and seal the quartz tube;

[0010] The quartz tube is placed in a muffle furnace and kept warm for a period of time;

[0011] After cooling, the product in the quartz tube, namely zinc cyanide nanomaterial, is collected.

[0012] Optionally, g-C3N4 is prepared by annealing urea in a tube furnace in an argon atmosphere.

[0013] Optionally, the annealing step is to heat the material to 550° C. at a heating rate of 15° C. / min, keep the temperature for 2 hours, and then cool the material naturally.

[0014] Optionally, urea is placed in a porcelain boat.

[0015] Optionally, the purity of the urea is greater than or equal to 99% by weight.

[0016] Optionally, the purity of the zinc powder is greater than or equal to 99% by weight.

[0017] Alternatively, keep in a muffle furnace for 2 hours.

[0018] Optionally, the temperature is increased to 750° C.-850° C. in a muffle furnace at a heating rate of 5° C. / min.

[0019] Optionally, the cooling method is natural cooling.

[0020] The beneficial effects of the present invention are:

[0021] The present invention uses g-C3N4 and zinc powder as raw materials, both of which are nontoxic. In addition, the zinc cyanide nanoparticles can be obtained after being treated in a muffle furnace for about 2 hours and cooled, and the reaction time is also short. Due to the advantages of the nontoxicity and short reaction time of preparing the zinc cyanide nanomaterial by the present invention, the present invention has good application prospects in the field of zinc cyanide nanomaterial preparation technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 The present invention is a flow chart of a method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials.

[0024] Figure 2 Schematic diagram of the preparation of g-C3N4 by annealing urea raw material.

[0025] Figure 3 This is an operation diagram for sealing a quartz tube under vacuum conditions.

[0026] Figure 4 SEM, EDS and XRD patterns of zinc cyanide powder annealed at 750℃.

[0027] Figure 5 SEM, EDS and XRD patterns of zinc cyanide powder annealed at 800℃.

[0028] Figure 6 SEM, EDS and XRD patterns of zinc cyanide powder annealed at 850℃. DETAILED DESCRIPTION

[0029] In order to make the implementation process of the present invention clearer, it will be described in detail below with reference to the accompanying drawings.

[0030] Example 1

[0031] Figure 1 The flowchart of the method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials of the present invention is as follows. To facilitate understanding of the scheme, the method of the present application is specifically introduced below. For the convenience of description, the method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials is referred to as the method. The method comprises:

[0032] S101. Mix g-C3N4 and zinc powder evenly and put them into a quartz tube.

[0033] g-C3N4 is in block form and has a mass of 0.5 g.

[0034] The zinc powder is in powder form, has a mass of 0.2 g, and a purity of 99% or greater by weight.

[0035] The mixing method is to grind and mix using an agate mortar for 10 minutes, which is conducive to the full contact between zinc powder and g-C3N4.

[0036] Quartz tube and quartz sealing plug (heating part) Figure 3 As shown, the diameter is 20 mm and the wall thickness is 2 mm, which is used to ensure a closed environment at high temperature, which is conducive to the formation of zinc cyanide.

[0037] S102. Use a rotary vane vacuum pump to evacuate the quartz tube to -0.08 MPa, and then use an oxyhydrogen flame to heat the quartz tube and the quartz sealing plug to seal them.

[0038] S103. Place the quartz tube in a muffle furnace and keep it warm for a period of time.

[0039] Place the quartz tube upright in a muffle furnace and heat to 750-850°C at a rate of 5°C / min. Keep in the muffle furnace for 2 hours to allow the reactants to fully react.

[0040] S104. After cooling, the product in the quartz tube, i.e., zinc cyanide nanomaterial, is collected.

[0041] After cooling naturally, the quartz tube was removed from the muffle furnace and transferred to a fume hood to prevent the product from being dispersed into the environment during collection. A diamond glass cutter was used to scratch the wall of the quartz tube, and the quartz tube was broken along the scratch to collect the product inside the quartz tube, namely the zinc cyanide nanomaterial.

[0042] In a quartz tube, g-C≡N≡ decomposes into cyanide gas at high temperatures, with the structural formula N≡C—C≡N. The cyanide gas reacts with zinc to form zinc cyanide, with the reaction equation Zn+2CN=Zn(CN). The present invention only requires two hours to produce the zinc cyanide nanomaterial, resulting in a short reaction time. Furthermore, the raw materials used are nontoxic. Therefore, the present invention has promising application prospects in the field of zinc cyanide nanomaterial preparation.

[0043] Example 2

[0044] Based on Example 1, g-C3N4 was prepared by secondary annealing of urea in a tube furnace under an argon atmosphere. The purity of urea was greater than or equal to 99% by weight. 10 g of urea was placed in a porcelain boat, which was placed in the middle of a tube furnace under an argon atmosphere. Figure 2 As shown. The temperature is raised to 550°C at a rate of 15°C per minute, kept at this temperature for 2 hours, and then cooled naturally to produce g-C3N4. The g-C3N4 is then placed in a porcelain boat, heated to 500°C at a rate of 15°C per minute, and subjected to secondary annealing at 500°C for 1 hour. Specifically, urea is loaded into a porcelain boat with a lid, which is then placed in the center of a tube furnace and introduced with argon. This can slow down the loss of intermediate products during the high-temperature decomposition and polycondensation of urea and increase the yield of g-C3N4.

[0045] In this embodiment, g-C3N4 is prepared by secondary annealing of urea in a tubular furnace under an argon atmosphere. The prepared g-C3N4 has a more fluffy characteristic and a lightweight spherical structure, which is conducive to the occurrence of subsequent reactions and makes the particle size distribution of the nano-zinc cyanide material more uniform.

[0046] Example 3

[0047] On the basis of Example 2, Figure 3 As shown, seal the quartz tube in a vacuum state. The specific operations are:

[0048] Step 1: Neck the quartz tube so that the inserted quartz sealing plug fits snugly in the neck and prevents it from falling. Install the quartz tube into the tube clamping device, turn on the corresponding station motor, adjust the speed to the appropriate level, and start rotating the tube. Position the nozzle of the oxyhydrogen torch with the flame adjusted to the appropriate position on the quartz tube. Quickly close the torch when the heated section of the tube contracts and deforms. Remove the quartz tube and prepare for the next step of loading the sample.

[0049] Step 2: Place g-C3N4 and zinc powder into a quartz tube and insert a quartz sealing plug.

[0050] Step 3: Seal the g-C3N4 and zinc powder in a quartz tube. Specifically, install the loaded quartz tube onto a rotary tube sealer and attach a clamp. Turn on the vacuum pump and pump down to -0.08 MPa. Turn on the motor and adjust the speed to an appropriate level. Ignite the flame and aim the oxyhydrogen flame at the quartz sealing plug to seal. Once the quartz tube and quartz sealing plug are fused, quickly turn off the oxyhydrogen flame.

[0051] This operation can isolate oxygen and moisture in the environment, prevent g-C3N4 and zinc powder from being oxidized during the reaction, and is conducive to the synthesis of zinc cyanide nanomaterials.

[0052] Example 4

[0053] Based on Example 3, the generated g-C3N4 and 0.2g of zinc powder were mixed and evenly placed in a quartz tube. The sealed quartz tube was placed in a muffle furnace and heated to 750°C at a rate of 5°C / min. The temperature was maintained for 2 hours, and then naturally cooled. The quartz tube was removed and broken to collect the zinc cyanide product.

[0054] Figure 4 The SEM, EDS, and XRD patterns of zinc cyanide powder annealed at 750°C show that the prepared zinc cyanide nanomaterial is in granular form. This type of zinc cyanide nanomaterial has a relatively stable structure and its crystal morphology is not easily destroyed.

[0055] Example 5

[0056] Based on Example 3, the generated g-C3N4 and 0.2g of zinc powder were mixed and evenly placed in a quartz tube. The sealed quartz tube was placed in a muffle furnace and heated to 800°C at a rate of 5°C / min. The temperature was maintained for 2 hours, and then naturally cooled. The quartz tube was removed and broken to collect the zinc cyanide product.

[0057] Figure 5 The SEM, EDS, and XRD patterns of zinc cyanide powder annealed at 800°C show that the prepared zinc cyanide nanomaterials are a mixture of flakes and granules, indicating a transitional state of morphological transformation.

[0058] Example 6

[0059] Based on Example 3, the generated g-C3N4 and 0.2g of zinc powder were mixed and evenly placed in a quartz tube. The sealed quartz tube was placed in a muffle furnace and heated to 850°C at a rate of 5°C / min. The temperature was maintained for 2 hours, and then naturally cooled. The quartz tube was removed and broken to collect the zinc cyanide product.

[0060] Figure 5 The SEM, EDS, and XRD patterns of zinc cyanide powder annealed at 850°C show that the prepared zinc cyanide nanomaterial is in the form of flakes, which has a larger specific surface area and more active sites for reaction.

[0061] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials, characterized in that: The method is prepared by using g-C3N4 and zinc powder as raw materials and adopting vacuum sealing sintering technology; the method comprises: Mix g-C3N4 and zinc powder evenly and put them into a quartz tube; Evacuate the quartz tube and seal the quartz tube; The quartz tube is placed in a muffle furnace and kept warm for a period of time; After cooling, the product in the quartz tube, namely zinc cyanide nanomaterial, is collected; The g-C3N4 is prepared by annealing urea in a tubular furnace in an argon atmosphere, and the g-C3N4 is a fluffy, lightweight spherical structure.

2. The method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials according to claim 1, wherein: The annealing step is to heat the temperature to 550° C. at a heating rate of 15° C. / min, keep the temperature for 2 hours, and then cool the temperature naturally.

3. The method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials according to claim 2, wherein: The urea is placed in a porcelain boat.

4. The method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials according to claim 3, wherein: The purity of the urea is greater than or equal to 99% by weight.

5. The method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials according to claim 1, wherein: The purity of the zinc powder is greater than or equal to 99% by weight.

6. The method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials according to claim 1, wherein: Keep warm in a muffle furnace for 2 hours.

7. The method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials according to claim 1, wherein: The temperature was raised to 750°C-850°C in a muffle furnace at a heating rate of 5°C / min.

8. The method for synthesizing zinc cyanide nanomaterials using non-toxic raw materials according to claim 1, wherein: The cooling method is natural cooling.

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