阅读说明：本技术 一种纤维网状氢氧化镁材料及其制备方法与应用 (Fiber mesh magnesium hydroxide material and preparation method and application thereof ) 是由 张波 李丽娟 李武 董亚萍 梁建 于 2021-07-23 设计创作，主要内容包括：本发明公开了一种纤维网状氢氧化镁材料及其制备方法与应用。所述制备方法包括：至少使作为阴极的金属基底、阳极与电解液共同构建电化学反应体系,所述电解液包括包含镁离子和添加剂的水溶液,所述添加剂包括黄原胶、葡萄糖或其衍生物和硫酸根离子的组合；使所述电化学反应体系通电进行电解,从而在阴极表面沉积形成具有纤维网状结构的氢氧化镁层。本发明制得的纤维网状氢氧化镁材料具有高比表面积和立体纤维状结构,可直接作为阻燃剂应用,或进一步脱水制成氧化镁粉体导热材料。在添加到塑料中应用时,由于该材料具有高比表面积,与塑料、橡胶等具有更好的结合力,同时因为它具有立体纤维空间结构,在各个方向上都能显著增强材料的力学性能。(The invention discloses a fiber mesh magnesium hydroxide material and a preparation method and application thereof. The preparation method comprises the following steps: at least a metal substrate as a cathode, an anode and an electrolyte are used together to construct an electrochemical reaction system, wherein the electrolyte comprises an aqueous solution containing magnesium ions and an additive, and the additive comprises xanthan gum, glucose or a derivative thereof and a combination of sulfate ions; electrifying the electrochemical reaction system for electrolysis, and depositing a magnesium hydroxide layer with a fiber net structure on the surface of the cathode. The fiber mesh magnesium hydroxide material prepared by the invention has high specific surface area and a three-dimensional fiber structure, and can be directly used as a flame retardant or further dehydrated to prepare a magnesium oxide powder heat conduction material. When the material is added into plastic for application, the material has high specific surface area, has better bonding force with plastic, rubber and the like, and can obviously enhance the mechanical property of the material in all directions because of the spatial structure of the three-dimensional fiber.)

1. A preparation method of a fiber mesh magnesium hydroxide material is characterized by comprising the following steps:

at least a conductive metal substrate as a cathode, an anode and an electrolyte are used together to construct an electrochemical reaction system, wherein the electrolyte comprises an aqueous solution containing magnesium ions and an additive, and the additive comprises xanthan gum, glucose or a derivative thereof and a combination of sulfate ions;

and electrifying the electrochemical reaction system for electrolysis, thereby depositing and forming a magnesium hydroxide layer on the surface of the cathode, wherein the magnesium hydroxide layer has a fiber net structure, namely a fiber net magnesium hydroxide material, and the electrode potential of the cathode is below-1.2V.

2. The method of claim 1, wherein: the glucose derivative comprises gluconic acid and/or gluconate, preferably, the gluconate comprises potassium gluconate and/or sodium gluconate.

3. The method of claim 1, wherein: the concentration of glucose or derivatives thereof in the electrolyte is 0.1 g/L-50 g/L; and/or the concentration of the xanthan gum in the electrolyte is 0.05 g/L-1 g/L.

4. The method of claim 1, wherein: the magnesium ions are derived from magnesium salts, and the magnesium salts comprise any one or combination of more than two of magnesium chloride, magnesium nitrate and magnesium sulfate; and/or the concentration of magnesium ions in the electrolyte is 0.01-5 mol/L.

5. The method of claim 1, wherein: the concentration of sulfate ions in the electrolyte is 0.1 g/L-100 g/L; and/or the sulfate ions are derived from sulfate, and the sulfate comprises any one or the combination of more than two of sodium sulfate, potassium sulfate and magnesium sulfate.

6. The method of claim 1, wherein: the electrochemical reaction system is a double-electrode or three-electrode system, preferably, the electrochemical reaction system further comprises a reference electrode, and the reference electrode is an Ag/AgCl electrode.

7. The method of claim 6, wherein: during the electrolysis, the electrode potential of the cathode is-5.0V to-1.2V relative to the reference electrode, the electrolysis time is 1min to 60min, and the temperature of the electrolyte is 5 ℃ to 70 ℃.

8. The production method according to claim 1, characterized by comprising: under the action of sulfate radicals, a magnesium hydroxide layer formed by deposition falls off from the surface of a cathode, and then the magnesium hydroxide layer is filtered and dried to obtain a powdery magnesium hydroxide material with a fiber net structure, preferably, the drying temperature is 40-100 ℃, and the drying time is 1-12 h;

and/or the anode comprises a lead plate, a platinum sheet or a titanium plate coated with a protective coating.

9. The fiber mesh-like magnesium hydroxide material prepared by the method of any one of claims 1 to 8, which has a three-dimensional fiber mesh-like structure, wherein the fiber-like magnesium hydroxide is contained in a diameter of 50nm to 800nm, and the fiber mesh-like magnesium hydroxide material microscopically exhibits a fiber mesh-like sheet-like structure with a thickness of 200nm to 6 μm, and preferably, the fiber mesh-like magnesium hydroxide material is fiber mesh-like magnesium hydroxide powder with a particle size of 800nm to 25 μm.

10. The application of the fiber mesh magnesium hydroxide material of claim 9 in the field of preparing flame retardants or magnesium oxide powder heat conduction materials.

Technical Field

The invention relates to a preparation method of a magnesium hydroxide powder material, in particular to a fiber mesh-shaped magnesium hydroxide powder material, a preparation method and application thereof, belonging to the technical field of magnesium hydroxide powder preparation.

Background

The magnesium hydroxide can be widely applied to the fields of flame-retardant filling, adsorption extraction and the like, can also be used as a precursor for preparing a special magnesium oxide material, and is an environment-friendly functional material. The magnesium hydroxide powder products with various shapes such as hexagonal sheets, rods, spheres, flower spheres and the like are prepared by the traditional method, and the magnesium hydroxide powder products have extremely rich product types from micron-sized to nanometer-sized in size specification. The magnesium hydroxide powder products are mature and utilized in industrial production, and meanwhile, the magnesium hydroxide still has the limitations of reducing the mechanical property of the material and the like when being added into products such as plastics, rubber and the like, and the phenomenon has a direct relation with the morphological characteristics of the magnesium hydroxide powder.

As described above, the magnesium hydroxide powder prepared by the prior art is usually in the form of hexagonal flakes, rods, spheres, flower balls, etc., each of which has a single structure as an individual, and when added to plastic and rubber products, due to the influence of its own properties and morphology, it is difficult to improve the mechanical properties of the material in various directions, and the mechanical properties of the material are often reduced. Meanwhile, the preparation method is usually a hydrothermal method or a microwave method, or the production conditions are harsh, the energy consumption is high, or the existing equipment is difficult to meet the industrialization requirements.

Disclosure of Invention

The invention mainly aims to provide a fiber mesh magnesium hydroxide powder material, a preparation method and application thereof, thereby overcoming the defects of the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

the embodiment of the invention provides a preparation method of a fiber mesh magnesium hydroxide powder material, which comprises the following steps:

at least a conductive metal substrate as a cathode, an anode and an electrolyte are used together to construct an electrochemical reaction system, wherein the electrolyte comprises an aqueous solution containing magnesium ions and an additive, and the additive comprises xanthan gum, glucose or a derivative thereof and a combination of sulfate ions;

and electrifying the electrochemical reaction system for electrolysis, thereby depositing and forming a magnesium hydroxide layer on the surface of the cathode, wherein the magnesium hydroxide layer has a fiber net structure, namely a fiber net magnesium hydroxide material, and the electrode potential of the cathode is below-1.2V.

In some preferred embodiments, the concentration of glucose or a derivative thereof in the electrolyte is 0.1g/L to 50 g/L.

Further, the concentration of the xanthan gum in the electrolyte is 0.05 g/L-1 g/L.

Furthermore, the concentration of magnesium ions in the electrolyte is 0.01-5 mol/L.

Furthermore, the concentration of sulfate ions in the electrolyte is 0.1 g/L-100 g/L.

In some preferred embodiments, during the electrolysis, the electrode potential of the cathode is-5.0V to-1.2V, the electrolysis time is 1min to 60min, and the temperature of the electrolyte is 5 ℃ to 70 ℃.

The embodiment of the invention also provides the fiber mesh-shaped magnesium hydroxide material prepared by the method, the fiber mesh-shaped magnesium hydroxide material has a three-dimensional fiber mesh structure, and the fiber mesh-shaped magnesium hydroxide material is microscopically represented as a fiber mesh-shaped sheet structure.

The embodiment of the invention also provides application of the fiber mesh magnesium hydroxide material in the fields of preparing flame retardants or magnesium oxide powder heat conduction materials and the like.

Compared with the traditional preparation method of magnesium hydroxide, the preparation method of the magnesium hydroxide powder material with the special fiber mesh structure provided by the invention has the advantages that xanthan gum, glucose or derivatives thereof and sulfate ions are added into electrolyte, and electrolysis is carried out under higher electrode potential, so that the prepared magnesium hydroxide powder material with the special fiber mesh structure has richer structural characteristics, such as high specific surface area and three-dimensional fiber structure, and can be directly used as a flame retardant or further dehydrated to prepare a magnesium oxide powder heat conduction material. When the material is added into plastic for application, the material has high specific surface area and better bonding force with plastic, rubber and the like, and simultaneously, because the material has a three-dimensional fiber space structure, the mechanical property of the material can be obviously enhanced in all directions, and the defect of poor mechanical property anisotropy caused by adding fibrous materials into the plastic and the rubber is avoided.

Meanwhile, the method adopts an electrochemical process, is a normal-temperature normal-pressure technology with extremely high industrial feasibility, and has simple steps and low requirements on equipment. Due to the addition of the sulfate radical, the problems of local difference, unsmooth and the like caused by the shedding of the electro-deposition magnesium hydroxide from the cathode surface can be solved, and the stable and continuous preparation of the fiber mesh magnesium hydroxide material is realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view of a process for preparing a fibrous network magnesium hydroxide powder material according to an exemplary embodiment of the present invention;

FIG. 2 is a scanning electron micrograph of the fibrous network magnesium hydroxide powder material obtained in example 1 of the present invention.

Detailed Description

In view of the defects in the prior art, the inventor of the present invention has made a long-term study and a great deal of practice to provide a preparation method of magnesium hydroxide powder with a special fiber network structure, and prepares an unreported novel magnesium hydroxide material, which has a high specific surface area and better bonding force with plastics, rubber and the like, and simultaneously can significantly enhance the mechanical properties of the material in all directions due to the three-dimensional fiber space structure, and does not have the defect of poor anisotropy of the mechanical properties caused by adding fibrous materials into the plastics and the rubber.

In the main concept of the invention, xanthan gum and glucose or derivatives thereof as additives and the high electrode potential (minus 1.2V calculated by Ag/AgCl electrode) of the cathode surface required for preparing the magnesium hydroxide forming the fiber network structure are the necessary conditions for constructing the fiber network structure. The sulfate radical is added, so that the magnesium hydroxide product can fall off from the surface of the cathode quickly, the continuous production of the electrolytic fiber reticular magnesium hydroxide powder is facilitated, and the stripping step which wastes time and labor is not needed.

The technical solution, its implementation and principles, etc. will be further explained as follows.

One aspect of the embodiments of the present invention provides a method for preparing a fiber mesh-shaped magnesium hydroxide material, including:

at least a conductive metal substrate as a cathode, an anode and an electrolyte are used together to construct an electrochemical reaction system, wherein the electrolyte comprises an aqueous solution containing magnesium ions and an additive, and the additive comprises xanthan gum, glucose or a derivative thereof and a combination of sulfate ions;

and electrifying the electrochemical reaction system for electrolysis, thereby depositing and forming a magnesium hydroxide layer on the surface of the cathode, wherein the magnesium hydroxide layer has a fiber net structure, namely a fiber net magnesium hydroxide material, and the electrode potential of the cathode is below-1.2V.

In some preferred embodiments, the glucose derivative includes gluconic acid and/or gluconate, wherein the gluconate includes potassium gluconate, sodium gluconate, etc., but is not limited thereto.

In the electrolysis process, in order to ensure that the magnesium hydroxide generated on the surface of the cathode has a fiber mesh structure, an additive, mainly xanthan gum and one or more of glucose, gluconic acid or gluconate (such as sodium gluconate and potassium gluconate) is added into the electrolyte. In order to ensure that the generated magnesium hydroxide product can continuously and smoothly fall off from the surface of the cathode and realize continuous production, sulfate radicals need to be introduced into the electrolyte.

The action mechanism of adding xanthan gum is as follows: the xanthan gum is a microbial extracellular polysaccharide, and the inventor of the invention unexpectedly finds that the xanthan gum has good compatibility with magnesium salts and the like and is easy to generate a synergistic effect with the magnesium salts in the process of electrodeposition of the magnesium salts. Xanthan gum has a wide pH range, and the process for electrodepositing magnesium hydroxide involved in the present invention is actually an acid-making process, and the structure of xanthan gum can be kept stable under conditions where the pH is easily changed in a wide range. Meanwhile, the xanthan gum is also an effective thickening agent, the viscosity of the solution can be obviously improved by using a small amount of xanthan gum, the state of a diffusion layer on the surface of a cathode is changed by influencing the diffusion coefficient, the growth trend of a magnesium hydroxide deposition layer is changed by the long-chain steric hindrance effect and the characteristic adsorption on the surface of the generated magnesium hydroxide crystal, and a fiber mesh structure is formed.

Furthermore, although xanthan gum has a remarkable effect in the process of electrolyzing to construct the magnesium hydroxide deposition layer with a fiber mesh structure, xanthan gum is easy to agglomerate in the preparation process, and the formed tiny undissolved agglomerated particles can influence the shape and performance of the fiber mesh magnesium hydroxide deposition layer. Therefore, the inventor of the present invention has further added glucose and derivatives thereof to the electrolyte, and has surprisingly found that the addition of one or more of glucose, gluconic acid or gluconate can significantly promote the uniform dissolution of xanthan gum in water, thereby avoiding the occurrence of agglomeration. Meanwhile, the glucose, the gluconic acid or the gluconate can improve the current distribution uniformity on the surface of the cathode in the electrolytic process, so that the thickness and the structure of the prepared fiber mesh-shaped magnesium hydroxide deposition layer are more uniform.

In some preferred schemes, the xanthan gum is added into the electrolyte so that the concentration of the xanthan gum in the finally obtained electrolyte is 0.05 g/L-1 g/L.

In some preferred schemes, the invention adds one or more of glucose, gluconic acid or gluconate (such as potassium gluconate and sodium gluconate) and the like into the electrolyte, so that the concentration of the glucose or the derivative thereof in the finally obtained electrolyte is 0.1 g/L-50 g/L calculated by glucose acid radicals.

In some preferred embodiments, the magnesium ion is derived from a magnesium salt, i.e., the electrolyte comprises an aqueous solution of a magnesium salt, wherein the solute magnesium salt may include any one or a combination of two or more of magnesium chloride, magnesium nitrate, magnesium sulfate, and the like, but is not limited thereto. Furthermore, the concentration of magnesium ions in the electrolyte is 0.01-5 mol/L.

In some preferred embodiments, the sulfate ion is derived from sulfate, i.e., the electrolyte comprises an aqueous sulfate solution, wherein the sulfate may include any one or a combination of two or more of sodium sulfate, potassium sulfate, magnesium sulfate, or the like, but is not limited thereto. Furthermore, the concentration of sulfate ions in the electrolyte is 0.1 g/L-100 g/L in terms of sulfate radicals.

The action mechanism of adding sulfate ions in the invention is as follows: sulfate ions are introduced into the electrolyte in a sufficient amount, and specifically, sodium sulfate, potassium sulfate, magnesium sulfate or the like can be added. Sulfate ions can significantly affect the release properties of the magnesium hydroxide product from the cathode surface. The specific index of the exfoliation performance is the exfoliation time, i.e. the length of time required from the initial generation of magnesium hydroxide on the cathode surface to exfoliation. The addition of a certain amount of sulfate ions into the electrolyte can loosen the combination of the magnesium hydroxide product and the cathode surface, promote the hydrogen emission, facilitate the entry of water molecules and obviously shorten the falling time of the magnesium hydroxide product.

In some preferred embodiments, the electrochemical reaction system is a two-electrode or three-electrode system.

Further, the electrochemical reaction system also comprises a reference electrode which is an Ag/AgCl electrode, but is not limited thereto.

In addition, the inventor proves through experiments that in the electrolytic system of the invention, higher electrode potential is also a necessary condition for preparing the fiber-network-shaped magnesium hydroxide deposition layer. The process of preparing the magnesium hydroxide by the electro-deposition is substantially water electrolysis, and the hydrogen evolution on the surface of a cathode and the enriched OH^-Can be used as precipitant and Mg in solution²⁺Reaction to form Mg (OH)₂. At higher electrode potential (the cathode surface is minus 1.2V relative to the saturated calomel electrode), OH is generated on the cathode surface^-The rate is greatly increased, and Mg (OH) on the surface of the cathode can be promoted₂The generation reaction is changed from chemical reaction to diffusion control, and the shape of the final product is directly influenced.

In some preferable schemes, during the electrolysis, the electrode potential of the cathode is-5.0V to-1.2V relative to the reference electrode, the electrolysis time is 1min to 60min, and the temperature of the electrolyte is 5 ℃ to 70 ℃.

In some preferred embodiments, the preparation method comprises: and (3) under the action of sulfate radicals, the deposited magnesium hydroxide layer falls off from the surface of the cathode, and then the magnesium hydroxide layer is filtered and dried to obtain the powdery magnesium hydroxide material with a fiber net structure.

Further, the drying temperature is 40-100 ℃, and the drying time is 1-12 h.

In the invention, the fallen magnesium hydroxide product is filtered and dried to form powder, and the microcosmic appearance of the powder is a special unreported fiber mesh structure. The material has high specific surface area and better bonding force with plastics, rubber and the like, and simultaneously, because of the three-dimensional fiber space structure, the mechanical property of the material can be obviously enhanced in all directions, and the defect of poor mechanical property anisotropy caused by adding fibrous materials into the plastics and the rubber is avoided.

That is to say, the preparation method of the magnesium hydroxide powder with the special fiber mesh structure provided by the invention firstly adopts an electrodeposition method to prepare the magnesium hydroxide layer with the fiber mesh structure on the metal surface, and xanthan gum and one or more of glucose, gluconic acid, sodium gluconate, potassium gluconate and other gluconate are added in the process, so that the generated magnesium hydroxide layer has the fiber mesh structure. Simultaneously, enough sulfate ions are introduced into the electrolyte to promote the magnesium hydroxide product to fall off from the surface of the cathode, and the magnesium hydroxide powder is obtained after filtering and drying, and the magnesium hydroxide powder still has a fiber net-shaped sheet structure on the microscopic scale.

Further, the invention firstly adopts an electrochemical method to carry out electrodeposition on the metal surface as a cathode, the electrolyte is a magnesium salt aqueous solution, and the anode can be a lead plate, a platinum sheet or a titanium plate coated with a protective coating, but is not limited to the above.

In some more specific embodiments, referring to fig. 1, the method for preparing the fiber-network-structured magnesium hydroxide powder material specifically includes the following steps:

step 1, adopting a double-electrode or three-electrode system to carry out electrolysis, wherein the cathode is a conductive metal substrate, and the anode is a lead plate, a titanium plate with a protective coating covered on the surface, a platinum sheet or other inert metal products.

And 2, the electrolyte is a magnesium salt aqueous solution, the solute can be one or more of magnesium chloride, magnesium nitrate and magnesium sulfate, and the concentration of magnesium ions in the solution is between 0.01 and 5 mol/L.

Step 3, adding xanthan gum into the electrolyte, wherein the concentration of the xanthan gum is between 0.05g/L and 1 g/L; simultaneously adding one or more of glucose, gluconic acid or gluconate (such as potassium gluconate and sodium gluconate), wherein the concentration of the gluconate is 0.1 g/L-50 g/L calculated by the gluconate radical. One of sodium sulfate, potassium sulfate or magnesium sulfate is added, and the concentration is between 0.1g/L and 100g/L according to the sulfate radical.

And 4, during electrolysis, the potential of the cathode electrode is between-5.0V and-1.2V (relative to an Ag/AgCl electrode), the electrolysis time is between 1min and 60min, the electrolysis temperature is between 5 ℃ and 70 ℃, and the fiber mesh-shaped magnesium hydroxide layer is obtained by electrodeposition on the surface of the cathode.

And 5, under the action of sulfate radicals, the magnesium hydroxide products continuously fall off from the surface of the cathode, and the products are filtered and dried to be powdery and have a good fiber mesh structure microscopically. Wherein the drying temperature is 40-100 ℃, and the drying time is 1-12 h.

Furthermore, the method adopts an electrochemical process, is a normal-temperature normal-pressure technology with extremely high industrial feasibility, and has simple steps and low requirements on equipment. Due to the addition of the sulfate radical, the problems of local difference, unsmooth and the like caused by the shedding of the electro-deposition magnesium hydroxide from the cathode surface can be solved, and the stable and continuous preparation of the fiber mesh magnesium hydroxide material is realized.

In another aspect, the present invention provides a fiber-network magnesium hydroxide material prepared by the method, wherein the fiber-network magnesium hydroxide material has a three-dimensional fiber-network structure, the fiber-network magnesium hydroxide material has a diameter of 50nm to 800nm, and the fiber-network magnesium hydroxide material microscopically shows a fiber-network sheet-like structure.

Further, the thickness of the sheet structure is 200 nm-6 μm.

Furthermore, the fiber mesh magnesium hydroxide material is fiber mesh magnesium hydroxide powder, and the particle size of the powder is 800 nm-25 μm.

Compared with the traditional hexagonal flaky, rodlike and spherical magnesium hydroxide, the magnesium hydroxide powder with the special fiber net structure prepared by the invention has more abundant structural characteristics, and has high specific surface area and a three-dimensional fibrous structure.

The embodiment of the invention also provides application of the fiber mesh magnesium hydroxide material in the fields of preparing flame retardants or magnesium oxide powder heat conduction materials and the like.

Furthermore, the fiber mesh-structured magnesium hydroxide powder has a high specific surface area and a three-dimensional fibrous structure, and can be directly used as a flame retardant or further dehydrated to be prepared into a magnesium oxide powder heat conduction material. When the material is added into plastic for application, the material has better bonding force with the plastic, rubber and the like due to high specific surface area, and simultaneously, the mechanical property of the material can be obviously enhanced in all directions due to the three-dimensional fiber space structure, so that the defect of poor mechanical property anisotropy caused by adding fibrous materials into the plastic and the rubber is overcome.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention are described in further detail below with reference to the accompanying drawings and several preferred embodiments, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. The test methods in the following examples are carried out under conventional conditions without specifying the specific conditions. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The reagents used in the following examples were all of analytical purity.

Example 1

Conducting metal is used as a cathode, a lead plate is used as an anode, and a double-electrode system is adopted for electrolysis. The electrolyte is magnesium nitrate aqueous solution, wherein the concentration of magnesium ions is 0.1 mol/L. Adding xanthan gum and glucose into the electrolyte to ensure that the concentration of the xanthan gum in the electrolyte is 1g/L and the concentration of the glucose in the electrolyte is 0.1 g/L. And simultaneously adding sodium sulfate to ensure that the concentration of sulfate ions in the electrolyte is 100 g/L. The potential of the cathode surface electrode is-2.4V relative to the Ag/AgCl electrode during electrolysis, the temperature of the electrolyte is 45 ℃, and the electrolysis time is 30 min. After the obtained fiber-network magnesium hydroxide product falls off from the surface of the cathode, the fiber-network magnesium hydroxide product is filtered and dried for 12 hours at the temperature of 40 ℃, the obtained magnesium hydroxide powder is detected to be in a good fiber network shape, and the scanning electron microscope photo of the magnesium hydroxide powder is shown in figure 2.

Example 2

Conducting metal is used as a cathode, a titanium plate covered with a protective coating on the surface is used as an anode, a three-electrode system is adopted for electrolysis, and a reference electrode is an Ag/AgCl electrode. The electrolyte is magnesium sulfate aqueous solution, wherein the total concentration of magnesium ions is 0.01mol/L, and sodium sulfate is added to ensure that the total concentration of sulfate radicals reaches 50 g/L. Adding xanthan gum and glucose into the electrolyte to ensure that the concentration of the xanthan gum in the electrolyte is 0.05g/L and the concentration of the glucose is 50 g/L. The potential of the cathode surface electrode is-1.2V relative to the Ag/AgCl electrode during electrolysis, the temperature of the electrolyte is 5 ℃, and the electrolysis time is 60 min. After the obtained fiber-network magnesium hydroxide product falls off from the surface of the cathode, the fiber-network magnesium hydroxide product is filtered and dried for 1 hour at 100 ℃, the obtained magnesium hydroxide powder is detected to be in a good fiber network shape, and the scanning electron microscope photo of the magnesium hydroxide powder is similar to that in the figure 2.

Example 3

The conductive metal is used as a cathode, a platinum sheet is used as an anode, and a double-electrode system is adopted for electrolysis. The electrolyte is an aqueous solution of magnesium chloride, wherein the concentration of magnesium ions is 5 mol/L. Adding xanthan gum and glucose into the electrolyte to ensure that the concentration of the xanthan gum in the electrolyte is 1g/L and the concentration of the glucose in the electrolyte is 15 g/L. Magnesium sulfate was added so that the sulfate radical concentration in the electrolyte was 0.1 g/L. The potential of the cathode surface electrode is-5.0V relative to the Ag/AgCl electrode during electrolysis, the temperature of the electrolyte is 70 ℃, and the electrolysis time is 1 min. After the obtained fiber-network magnesium hydroxide product falls off from the surface of the cathode, the fiber-network magnesium hydroxide product is filtered and dried for 8 hours at 50 ℃, the obtained magnesium hydroxide powder is detected to be in a good fiber network shape, and the scanning electron microscope photo of the magnesium hydroxide powder is similar to that in the figure 2.

Example 4

The conductive metal is used as a cathode, a platinum sheet is used as an anode, and a double-electrode system is adopted for electrolysis. The electrolyte is an aqueous solution of magnesium chloride, wherein the concentration of magnesium ions is 1 mol/L. Adding xanthan gum and gluconic acid into the electrolyte to ensure that the concentration of the xanthan gum in the electrolyte is 0.1g/L and the concentration of gluconic acid root is 35 g/L. Potassium sulfate was added so that the sulfate radical concentration in the electrolyte was 10 g/L. The potential of the cathode surface electrode is-3.0V relative to the Ag/AgCl electrode during electrolysis, the temperature of the electrolyte is 50 ℃, and the electrolysis time is 10 min. After the obtained fiber-network magnesium hydroxide product falls off from the surface of the cathode, the fiber-network magnesium hydroxide product is filtered and dried for 8 hours at the temperature of 60 ℃, the obtained magnesium hydroxide powder is detected to be in a good fiber network shape, and the scanning electron microscope photo of the magnesium hydroxide powder is similar to that in the figure 2.

Example 5

The conductive metal is used as a cathode, a platinum sheet is used as an anode, and a double-electrode system is adopted for electrolysis. The electrolyte is an aqueous solution of magnesium nitrate, wherein the concentration of magnesium ions is 3 mol/L. Adding xanthan gum, potassium gluconate and sodium gluconate into the electrolyte to ensure that the concentration of the xanthan gum in the electrolyte is 0.5g/L and the concentration of gluconic acid radical is 25g/L in terms of gluconic acid radical. Magnesium sulfate was added so that the sulfate radical concentration in the electrolyte was 20 g/L. The potential of the cathode surface electrode is-1.4V relative to the Ag/AgCl electrode during electrolysis, the temperature of the electrolyte is 55 ℃, and the electrolysis time is 15 min. After the obtained fiber-network magnesium hydroxide product falls off from the surface of the cathode, the fiber-network magnesium hydroxide product is filtered and dried for 6 hours at the temperature of 80 ℃, the obtained magnesium hydroxide powder is detected to be in a good fiber network shape, and the scanning electron microscope photo of the magnesium hydroxide powder is similar to that in the figure 2.

Comparative example 1

This comparative example is substantially the same as example 1 except that: no xanthan gum and glucose were added to the electrolyte.

Finally, the magnesium hydroxide deposited on the surface of the electrode falls off in a large area, and a complete film layer is difficult to form.

Comparative example 2

This comparative example is substantially the same as example 1 except that: xanthan gum was added only to the electrolyte, no glucose was added. The results show that xanthan gum is difficult to dissolve uniformly in the absence of glucose, and is mostly present in solution as small particles. Finally, the magnesium hydroxide deposited on the surface of the electrode falls off in a large area, and a complete film layer is difficult to form.

Comparative example 3

This comparative example is substantially the same as example 1 except that: only glucose was added to the electrolyte, no xanthan gum was added.

Finally, the magnesium hydroxide deposited on the surface of the electrode falls off in a large area, and a complete film layer is difficult to form.

Comparative example 4

This comparative example is substantially the same as example 1 except that: the surface electrode potential of the cathode during electrolysis is-0.5V.

The magnesium hydroxide finally deposited on the surface of the electrode is of a sheet structure, and a fiber net structure does not exist.

Comparative example 5

This comparative example is substantially the same as example 1 except that: sodium sulfate was not added to the electrolyte.

However, the results show that the surface of the electrode is covered by a large-area magnesium hydroxide deposition layer, the electrodeposited magnesium hydroxide cannot smoothly fall off from the surface of the cathode, the problems of local difference, smoothness and the like exist, and the preparation of the magnesium hydroxide powder capable of continuously falling off cannot be realized.

Comparative example 6

This comparative example is substantially the same as example 1 except that: the concentration range of xanthan gum is lower than 0.05g/L, or higher than 1 g/L.

The results show that the magnesium hydroxide film layer finally deposited on the surface of the electrode is flaky and not fiber net-shaped.

In addition, the inventors of the present invention have also made experiments with other materials, process operations, and process conditions described in the present specification with reference to the above examples, and have obtained preferable results.

While the invention has been described with reference to illustrative embodiments, it will be understood by those skilled in the art that various other changes, omissions and/or additions may be made and substantial equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.