CN108837803A - A kind of layered double-hydroxide loads the preparation method of biological carbon composite - Google Patents

Abstract

The invention discloses a preparation method of a layered double hydroxide loaded biochar composite material, which relates to a preparation method of a biochar composite material. The purpose of the invention is to solve the problem that the existing biochar material has a low specific surface area and limited ability to absorb anions in sewage. Methods: 1. Preparation of mixture composite material by deposition; 2. Pyrolysis and carbonization to obtain layered double hydroxide loaded biochar composite material. The specific surface area of the layered double hydroxide-loaded biochar composite material prepared by the present invention is 13.19m ² /g-56.11m ² /g, and the adsorption capacity for removing phosphate is 26.47mg(P)/g-33.05mg( P)/g. The layered double hydroxide-loaded biochar composite material prepared by the invention is used for the removal of anions in sewage.

Description

A kind of preparation method of layered double hydroxide loaded biochar composite material

technical field

The invention relates to a preparation method of a biochar composite material.

Background technique

Layered double hydroxide (LDH) is an anionic clay with high anion adsorption capacity, which is composed of positively charged metal hydroxide sheets and intercalated anions and water molecules. Layered double hydroxides (LDHs) can be easily obtained by a simple co-precipitation method, but their application in water treatment is limited due to the close layer packing and the formation of granular or massive structures.

The specific surface area of the existing biochar is 5m ² /g～15m ² /g, and the surface of the biochar is negatively charged, so the ability to adsorb anions in sewage is limited, and the adsorption capacity for removing phosphate is 2mg(P) /g～15mg(P)/g, which hinders the application of biochar in water treatment.

Contents of the invention

The purpose of the present invention is to solve the problem of low specific surface area of existing biochar materials and limited ability to absorb anions in sewage, and to provide a preparation method of layered double hydroxide-loaded biochar composite materials.

A preparation method of a layered double hydroxide-loaded biochar composite material is specifically completed according to the following steps:

1. Preparation of mixture composite materials:

①. Cut and pulverize the biomass material, wash it with distilled water for 5 to 10 times, then dry it at a temperature of 70°C to 90°C, and then pass the dried biomass material through a 50-mesh sieve to 200-mesh sieve to obtain raw Substance material fine powder;

②. Mix biomass material fine powder, divalent metal salt solution and trivalent metal salt solution, and then stir and react at a stirring speed of 1000r/min-1500r/min for 1h-3h to obtain reaction solution I; then use buffer solution Adjust the pH value of the reaction solution I to 8-12, then deposit at room temperature for 15h-25h, and then carry out vacuum filtration, and dry the solid substance obtained after vacuum filtration at a temperature of 70°C-100°C to obtain dry a mixture of composite materials;

The concentration of the divalent metal salt solution described in step 1.2 is 0.1mol/L～1mol/L;

The concentration of the trivalent metal salt solution described in step 1.2 is 0.1mol/L～0.5mol/L;

The volume ratio of the mass of the biomass material fine powder described in step 1.2 to the divalent metal salt solution is (1g～5g):(100mL～500mL);

The molar ratio of the divalent metal salt in the divalent metal salt solution described in step 1.2 to the trivalent metal salt in the trivalent metal salt solution is (1～5):1;

2. Place the dried mixture composite material in a tube furnace, pass an inert gas into the tube furnace, raise the temperature of the tube furnace to 500°C~700°C under the protection of the inert gas, and then heat the tube furnace at a temperature of 500°C~700°C ℃ under the protection of an inert gas atmosphere to obtain a layered double hydroxide-supported biochar composite material.

Principle and advantage of the present invention:

1. The present invention uses biomass materials as raw materials, and the layered double hydroxide-loaded biochar composite material prepared by the method of combining coprecipitation and pyrolysis activation has a relatively large specific surface area. The layered double hydroxide prepared by the present invention The specific surface area of the hydroxide-loaded biochar composite material is 13.19m ² /g-56.11m ² /g, and the layered double hydroxide is uniformly dispersed on the surface of the biochar material, thus improving the dispersion of the layered double hydroxide Spend;

2. The compound obtained by mixing and co-precipitating the biomass material with the metal salt, and then performing pyrolysis, activates the biochar to a certain extent, which is beneficial to increase the specific surface area of the biochar, and the layered double hydroxide The synergistic effect with biochar materials improves its utilization efficiency in the environment;

3. Biomass materials (such as corn stalks), as a kind of agricultural waste, reduce the cost of synthetic materials due to their low cost and easy availability;

Four, the present invention combines layered double hydroxide (LDH) with positive charges and agricultural waste biomass materials to prepare composite materials, which can simultaneously expand the interlayer distance of layered double hydroxide (LDH) and further improve the The adsorption performance of phosphate, the adsorption capacity of the layered double hydroxide loaded biochar composite material prepared by the present invention to remove phosphate is 26.47mg(P)/g～33.05mg(P)/g;

5. The preparation method of the present invention is simple and convenient, and the raw materials are cheap and easy to obtain, so it is suitable for large-scale synthesis and preparation;

The layered double hydroxide-loaded biochar composite material prepared by the invention is used for the removal of anions in sewage.

Description of drawings

Fig. 1 is the scanning electron micrograph of the layered Zn-Al double hydroxide loaded biochar composite material prepared by embodiment one;

Fig. 2 is the scanning electron micrograph of the layered Mg-Al double hydroxide loaded biochar composite material prepared in embodiment two;

Fig. 3 is the scanning electron micrograph of the layered Ni-Fe double hydroxide loaded biochar composite material that embodiment three prepares;

Fig. 4 is the XRD spectrogram of three kinds of layered double hydroxide loaded biochar composite materials, among the figure 1 is the XRD curve of the layered Zn-Al double hydroxide loaded biochar composite material prepared in Example 1, 2 is The XRD curve of the layered Mg-Al double hydroxide loaded biochar composite material prepared in embodiment two, 3 is the XRD curve of the layered Ni-Fe double hydroxide loaded biochar composite material prepared in embodiment three;

Fig. 5 is the nitrogen adsorption-desorption spectrogram of the layered Zn-Al double hydroxide loaded biochar composite material prepared in Example 1;

Fig. 6 is the nitrogen adsorption-desorption spectrogram of the layered Mg-Al double hydroxide loaded biochar composite material prepared in embodiment two;

Fig. 7 is the nitrogen adsorption-desorption spectrum of the layered Ni-Fe double hydroxide-supported biochar composite material prepared in Example 3.

Detailed ways

The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

Embodiment 1: This embodiment is a preparation method of a layered double hydroxide-loaded biochar composite material, which is specifically completed according to the following steps:

1. Preparation of mixture composite materials:

①. Cut and pulverize the biomass material, wash it with distilled water for 5 to 10 times, then dry it at a temperature of 70°C to 90°C, and then pass the dried biomass material through a 50-mesh sieve to 200-mesh sieve to obtain raw Substance material fine powder;

②. Mix biomass material fine powder, divalent metal salt solution and trivalent metal salt solution, and then stir and react at a stirring speed of 1000r/min-1500r/min for 1h-3h to obtain reaction solution I; then use buffer solution Adjust the pH value of the reaction solution I to 8-12, then deposit at room temperature for 15h-25h, and then carry out vacuum filtration, and dry the solid substance obtained after vacuum filtration at a temperature of 70°C-100°C to obtain dry a mixture of composite materials;

The concentration of the divalent metal salt solution described in step 1.2 is 0.1mol/L～1mol/L;

The concentration of the trivalent metal salt solution described in step 1.2 is 0.1mol/L～0.5mol/L;

The volume ratio of the mass of the biomass material fine powder described in step 1.2 to the divalent metal salt solution is (1g～5g):(100mL～500mL);

The molar ratio of the divalent metal salt in the divalent metal salt solution described in step 1.2 to the trivalent metal salt in the trivalent metal salt solution is (1～5):1;

2. Place the dried mixture composite material in a tube furnace, pass an inert gas into the tube furnace, raise the temperature of the tube furnace to 500°C~700°C under the protection of the inert gas, and then heat the tube furnace at a temperature of 500°C~700°C ℃ under the protection of an inert gas atmosphere to obtain a layered double hydroxide-supported biochar composite material.

Principles and advantages of this embodiment:

1. In this embodiment, biomass materials are used as raw materials, and the layered double hydroxide-loaded biochar composite material prepared by the combination of co-precipitation and pyrolysis activation has a relatively large specific surface area. The layer prepared in this embodiment The specific surface area of the layered double hydroxide-loaded biochar composite material is 13.19m ² /g-56.11m ² /g, and the layered double hydroxide is uniformly dispersed on the surface of the biochar material, thus improving the performance of the layered double hydroxide. the degree of dispersion;

2. The compound obtained by mixing and co-precipitating the biomass material with the metal salt, and then performing pyrolysis, activates the biochar to a certain extent, which is beneficial to increase the specific surface area of the biochar, and the layered double hydroxide The synergistic effect with biochar materials improves its utilization efficiency in the environment;

3. Biomass materials (such as corn stalks), as a kind of agricultural waste, reduce the cost of synthetic materials due to their low cost and easy availability;

4. In this embodiment, a positively charged layered double hydroxide (LDH) and agricultural waste biomass materials are combined to prepare a composite material, which can simultaneously expand the layer spacing of the layered double hydroxide (LDH) and further improve For the adsorption performance of phosphate, the adsorption capacity of the layered double hydroxide-loaded biochar composite material prepared in this embodiment to remove phosphate is 26.47mg(P)/g～33.05mg(P)/g;

5. The preparation method of this embodiment is simple and convenient, and the raw materials are cheap and easy to obtain, so it is suitable for large-scale synthesis and preparation;

The layered double hydroxide-loaded biochar composite material prepared in this embodiment is used for the removal of anions in sewage.

Embodiment 2: This embodiment differs from Embodiment 1 in that the biomass material described in step ① is one of corn stalks, rice husks, sawdust and bamboo poles or a mixture of several of them. Others are the same as in the first embodiment.

Specific embodiment three: the difference between this embodiment and specific embodiment one or two is that the divalent metal salt solution described in step one 2. is divalent magnesium salt solution, divalent nickel salt solution, divalent copper salt solution and One or a mixture of divalent zinc salt solutions. Others are the same as in the first or second embodiment.

Embodiment 4: The difference between this embodiment and Embodiment 1 to 3 is that the divalent magnesium salt in the divalent magnesium salt solution is MgCl ₂ , MgSO ₄ or Mg(NO ₃ ) ₂ ; the described The divalent nickel salt in the divalent nickel salt solution is NiCl ₂ , Ni(NO ₃ ) ₂ or NiSO ₄ ; the divalent copper salt in the divalent copper salt solution is CuCl ₂ , Cu(NO ₃ ) ₂ or CuSO ₄ ; The divalent zinc salt in the divalent zinc salt solution is ZnCl ₂ , ZnSO ₄ or Zn(NO ₃ ) ₂ ·6H ₂ O. Others are the same as those in the first to third specific embodiments.

Specific embodiment five: this embodiment is different from one of specific embodiments one to four: the trivalent metal salt solution described in step 1.2 is trivalent aluminum salt solution, trivalent chromium salt solution and ferric salt solution one or a mixture of several of them. Others are the same as one of the specific embodiments 1 to 4.

Embodiment 6: This embodiment is different from Embodiment 1 to Embodiment 5 in that: the trivalent aluminum salt in the trivalent aluminum salt solution is AlCl ₃ , Al ₂ (SO ₄ ) ₃ or Al(NO ₃ ) ₂ ·9H ₂ O; the trivalent chromium salt in the trivalent chromium salt solution is Cr(NO ₃ ) ₃ , CrCl ₃ ·6H ₂ O or Cr ₂ (SO ₄ ) ₃ ·6H ₂ O; The ferric salt in the valent iron salt solution is FeCl ₃ ·6H ₂ O, Fe(NO ₃ ) ₃ ·9H ₂ O or Fe ₂ (SO ₄ ) ₃ . Others are the same as one of the specific embodiments 1 to 5.

Embodiment 7: This embodiment differs from one of Embodiments 1 to 6 in that: the buffer solution described in step 1.2 is a mixture of NaOH, Na ₂ CO ₃ and water; the NaOH in the buffer solution is The concentration is 0.1mol/L-1mol/L, and the concentration of Na ₂ CO ₃ is 0.1mol/L-1mol/L. Others are the same as one of the specific embodiments 1 to 6.

Embodiment 8: The difference between this embodiment and one of Embodiments 1 to 7 is that the inert gas described in step 2 is nitrogen or argon. Others are the same as one of the specific embodiments 1 to 7.

Embodiment 9: The difference between this embodiment and Embodiment 1 to Embodiment 8 is that in step 2, the tube furnace is heated to 500°C to 700°C under the protection of inert gas, and the heating rate is 8°C/min to 12°C. °C/min. Others are the same as one of the specific embodiments 1 to 8.

Embodiment 10: This embodiment is different from Embodiment 1 to Embodiment 9 in that: the pyrolysis time described in step 2 is 0.5-2 hours. Others are the same as one of the specific embodiments 1 to 9.

The following examples of the present invention are described in detail, and the following examples are implemented on the premise of the technical solution of the present invention, and detailed implementation schemes and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

Embodiment 1: The preparation method of layered Zn-Al double hydroxide loaded biochar composite material is specifically completed according to the following steps:

1. Preparation of mixture composite materials:

①. Cutting and crushing the biomass material, washing with distilled water for 8 times, drying at a temperature of 80°C, and passing the dried biomass material through a 100-mesh sieve to obtain fine powder of biomass material;

The biomass material described in step 1.1 is corn stalks;

②. Mix the biomass material fine powder, ZnCl ₂ solution and AlCl ₃ solution, and then stir and react at a stirring speed of 1000r/min for 2 hours to obtain the reaction solution I; then use a buffer solution to adjust the pH value of the reaction solution I to 10 , and then deposit at room temperature for 18 hours, then perform vacuum filtration, and dry the solid substance obtained after vacuum filtration at a temperature of 80° C. to obtain a dry mixture composite material;

The concentration of the ZnCl solution described in step _1.2 . is 0.4mol/L;

_The concentration of the AlCl solution described in step 1.2. is 0.2mol/L;

The quality of the biomass material fine powder described in step _2. and ZnCl The volume ratio of the solution is 3g:300mL;

_The molar ratio of ZnCl in the ZnCl solution described in step _1.2 to AlCl in the AlCl solution is ₂ : ₁ ;

The buffer solution described in step 1 ② is a mixture of _NaOH , _Na2CO3 and water; the concentration of _NaOH in the buffer solution is 0.5mol/L, and the concentration of _Na2CO3 is 0.5mol/L;

2. Put the dried mixture composite material in a tube furnace, feed nitrogen gas into the tube furnace, and raise the temperature of the tube furnace to 600 °C at a heating rate of 10 °C/min under the protection of nitrogen gas, and then The layered Zn-Al double hydroxide-supported biochar composite material was obtained by pyrolysis at 600°C for 1 h under the protection of a nitrogen gas atmosphere.

Fig. 1 is the scanning electron micrograph of the layered Zn-Al double hydroxide loaded biochar composite material prepared by embodiment one;

It can be seen from Figure 1 that the granular Zn-Al double hydroxide is dispersed on the biochar matrix. Compared with the original biochar with smooth surface, the pyrolytic treatment of the mixture of double hydroxide and biomass can effectively increase the specific surface area of the original biochar.

Example 1 Preparation of layered Zn-Al double hydroxide-supported biochar composite material to remove K ₂ HPO ₄ , and its adsorption capacity is 33.05 mg(P)/g.

Embodiment two: the preparation method of layered Mg-Al double hydroxide loaded biochar composite material is specifically completed according to the following steps:

1. Preparation of mixture composite materials:

①. Cutting and crushing the biomass material, washing with distilled water for 8 times, drying at a temperature of 80°C, and passing the dried biomass material through a 100-mesh sieve to obtain fine powder of biomass material;

The biomass material described in step 1.1 is corn stalks;

②. Mix biomass material fine powder, MgCl ₂ solution and AlCl ₃ solution, and then stir and react at a stirring speed of 1000r/min for 2 hours to obtain reaction solution I; then use buffer solution to adjust the pH value of reaction solution I to 10 , and then deposit at room temperature for 18 hours, then perform vacuum filtration, and dry the solid substance obtained after vacuum filtration at a temperature of 80° C. to obtain a dry mixture composite material;

The MgCl described in step _2. The concentration of the solution is 0.4mol/L;

_The concentration of the AlCl solution described in step 1.2. is 0.2mol/L;

The quality of the biomass material fine powder described in step _2. and MgCl The volume ratio of the solution is 3g:300mL;

_The molar ratio of MgCl in the MgCl solution described in step _1.2 to AlCl in the AlCl solution is ₂ : ₁ ;

The buffer solution described in step 1 ② is a mixture of _NaOH , _Na2CO3 and water; the concentration of _NaOH in the buffer solution is 0.5mol/L, and the concentration of _Na2CO3 is 0.5mol/L;

2. Put the dried mixture composite material in a tube furnace, feed nitrogen gas into the tube furnace, and raise the temperature of the tube furnace to 600 °C at a heating rate of 10 °C/min under the protection of nitrogen gas, and then The layered Mg-Al double hydroxide-supported biochar composite material was obtained by pyrolysis at 600°C for 1 h under the protection of a nitrogen gas atmosphere.

Fig. 2 is the scanning electron micrograph of the layered Mg-Al double hydroxide loaded biochar composite material prepared in embodiment two;

It can be seen from Figure 2 that the fine particles of Mg-Al double hydroxide are evenly loaded on the surface of biochar.

The layered Mg-Al double hydroxide-supported biochar composite material prepared in Example 2 removed K ₂ HPO ₄ , and its adsorption capacity was 30.93 mg(P)/g.

Embodiment three: the preparation method of layered Ni-Fe double hydroxide loaded biochar composite material is specifically according to

The following steps are done:

1. Preparation of mixture composite materials:

①. Cutting and crushing the biomass material, washing with distilled water for 8 times, drying at a temperature of 80°C, and passing the dried biomass material through a 100-mesh sieve to obtain fine powder of biomass material;

The biomass material described in step 1.1 is corn stalks;

②. Mix biomass material fine powder, Ni(NO ₃ ) ₂ solution and FeCl ₃ 6H ₂ O solution, then stir and react at a stirring speed of 1000r/min for 2 hours to obtain reaction solution I; then use buffer solution to react The pH value of liquid I was adjusted to 10, and then deposited at room temperature for 18 hours, and then subjected to vacuum filtration, and the solid substance obtained after vacuum filtration was dried at a temperature of 80° C. to obtain a dry mixture composite material;

The concentration of the Ni(NO ₃ ) ₂ solution described in step 1.2 is 0.4mol/L;

The concentration of the FeCl ₃ ·6H ₂ O solution described in step 1 ② is 0.2mol/L;

The mass of the biomass material fine powder described in step 2. and Ni(NO ₃ ) _The volume ratio of the solution is 3g:300mL;

The molar ratio of Ni(NO ₃ ) ₂ in the Ni(NO ₃ ) ₂ solution and FeCl ₃ .6H 2 O in the FeCl ₃ .6H ₂ O solution described in step _1.2 is 2:1;

The buffer solution described in step 1 ② is a mixture of _NaOH , _Na2CO3 and water; the concentration of _NaOH in the buffer solution is 0.5mol/L, and the concentration of _Na2CO3 is 0.5mol/L;

2. Put the dried mixture composite material in a tube furnace, feed nitrogen gas into the tube furnace, and raise the temperature of the tube furnace to 600 °C at a heating rate of 10 °C/min under the protection of nitrogen gas, and then The layered Ni-Fe double hydroxide-supported biochar composite material was obtained by pyrolysis at 600°C for 1 h under the protection of a nitrogen gas atmosphere.

Fig. 3 is the scanning electron micrograph of the layered Ni-Fe double hydroxide loaded biochar composite material that embodiment three prepares;

It can be seen from Figure 3 that the needle-like and flaky Ni-Fe double hydroxides grow uniformly on the surface of the biochar, and the dispersion is good.

The layered Ni-Fe double hydroxide-supported biochar composite material prepared in Example 3 removed K ₂ HPO ₄ , and its adsorption capacity was 26.47 mg(P)/g.

Fig. 4 is the XRD spectrogram of three kinds of layered double hydroxide loaded biochar composite materials, among the figure 1 is the XRD curve of the layered Zn-Al double hydroxide loaded biochar composite material prepared in Example 1, 2 is The XRD curve of the layered Mg-Al double hydroxide loaded biochar composite material prepared in embodiment two, 3 is the XRD curve of the layered Ni-Fe double hydroxide loaded biochar composite material prepared in embodiment three;

The crystal structure can be clarified by the XRD spectrum in Figure 4. For layered Zn-Al double hydroxide-supported biochar composites, the corresponding peaks at 2θ values of 31.85°, 34.55°, 36.36°, 39.09°, 45.87° and 56.75° indicated the presence of alumina and zinc oxide. For Mg-Al double hydroxide-supported biochar composites and layered Ni-Fe double hydroxide-supported biochar composites, the XRD patterns show some strong diffraction peaks, mainly belonging to single metal oxides or double metal oxides . XRD results showed that layered double hydroxide flakes were successfully supported on biochar.

Comparative example: the preparation method of biochar is specifically completed according to the following steps:

1. ①. Cutting and pulverizing the biomass material, washing with distilled water for 8 times, drying at a temperature of 80°C, and passing the dried biomass material through a 100-mesh sieve to obtain fine biomass material powder;

The biomass material described in step 1.1 is corn stalks;

②. Put the fine powder of biomass material in the tube furnace, pass nitrogen gas into the tube furnace, under the protection of nitrogen gas, raise the temperature of the tube furnace to 600 °C at a heating rate of 10 °C/min, and then Biochar was obtained by pyrolysis at 600°C for 1 h under the protection of a nitrogen gas atmosphere.

Fig. 5 is the nitrogen adsorption-desorption spectrogram of the layered Zn-Al double hydroxide loaded biochar composite material prepared in Example 1;

Fig. 6 is the nitrogen adsorption-desorption spectrogram of the layered Mg-Al double hydroxide loaded biochar composite material prepared in embodiment two;

Fig. 7 is the nitrogen adsorption-desorption spectrum of the layered Ni-Fe double hydroxide-supported biochar composite material prepared in Example 3.

According to IUPAC classification, the layered Zn-Al double hydroxide-loaded biochar composite material prepared in Example 1, the layered Mg-Al double hydroxide-loaded biochar composite material prepared in Example 2 and the layer prepared in Example 3 The adsorption isotherms of these three samples of Ni-Fe double hydroxide-supported biochar composites are type IV isotherms with H3 hysteresis loop, implying the presence of mesopores in the three composites. Preparation of layered Zn-Al double hydroxide-supported biochar composite material in Example 1, layered Mg-Al double hydroxide-supported biochar composite material prepared in Example 2, and layered Ni-Fe bicarbonate composite material prepared in Example 3 The specific surface areas of the hydroxide-loaded biochar composites were 29.85m ² /g, 13.19m ² /g and 56.11m ² /g respectively. However, the specific surface area of the raw biochar (the biochar prepared in the comparative example) is 6.00 m ² /g. Apparently, the addition of layered double hydroxide changed the pore structure and surface area of biochar, providing more abundant active sites for phosphate adsorption.

Claims (10)

1. the preparation method that a kind of layered double-hydroxide loads biological carbon composite, it is characterised in that a kind of double hydrogen-oxygens of stratiform What the preparation method that compound loads biological carbon composite was specifically realized by the following steps：

One, mixture composite material is prepared：

1., cutting crushing is carried out to biological material, reuse distilled water clean 5 times~10 times, then temperature be 70 DEG C~90 It is dry at DEG C, then dry biological material is crossed into 50 meshes~200 meshes, obtain biological material fine powder；

2., biological material fine powder, divalent metal salting liquid and trivalent metal salting liquid mixed, then low whipping speed is It is stirred to react 1h~3h under 1000r/min~1500r/min, obtains reaction solution I；Then use buffer solution by reaction solution I PH value is adjusted to 8~12, then deposits 15h~25h at room temperature, then be filtered by vacuum, the solid that will be obtained after vacuum filtration Substance is dry at being 70 DEG C~100 DEG C in temperature, obtains dry mixture composite material；

Step 1 2. described in divalent metal salting liquid concentration be 0.1mol/L~1mol/L；

Step 1 2. described in trivalent metal salting liquid concentration be 0.1mol/L~0.5mol/L；

Step 1 2. described in biological material fine powder quality and divalent metal salting liquid volume ratio be (1g~5g): (100mL~500mL)；

Step 1 2. described in divalent metal salting liquid in divalent metal salt and trivalent metal salting liquid in trivalent metal The molar ratio of salt is (1~5):1；

Two, dry mixture composite material is placed in tube furnace, inert gas is passed through into tube furnace, protected in inert gas Tube furnace is warming up to 500 DEG C~700 DEG C, then the heat in the case where temperature is 500 DEG C~700 DEG C and inert gas atmosphere is protected under shield Solution obtains layered double-hydroxide and loads biological carbon composite.

2. a kind of layered double-hydroxide according to claim 1 loads the preparation method of biological carbon composite, special Sign be step 1 1. described in biological material be one of corn stover, rice husk, sawdust and bamboo pole or in which several Mixture.

3. a kind of layered double-hydroxide according to claim 1 loads the preparation method of biological carbon composite, special Levying the divalent metal salting liquid described in being step 1 2. is divalent magnesium salt solution, divalent nickel salt solution, cupric salt solution With the mixed liquor of one or more of divalent zinc salt solution.

4. a kind of layered double-hydroxide according to claim 3 loads the preparation method of biological carbon composite, special Sign is in the divalent magnesium salt solution that divalent magnesium salts is MgCl₂、MgSO₄Or Mg (NO₃)₂；In the divalent nickel salt solution Divalent nickel salt is NiCl₂、Ni(NO₃)₂Or NiSO₄；Cupric salt is CuCl in the cupric salt solution₂、Cu(NO₃)₂Or CuSO₄；Divalent zinc salt is ZnCl in the divalent zinc salt solution₂、ZnSO₄Or Zn (NO₃)₂·6H₂O。

5. a kind of layered double-hydroxide according to claim 1 loads the preparation method of biological carbon composite, special Levying the trivalent metal salting liquid described in being step 1 2. is trivalent aluminium salt solution, trivalent chromium salt solution and ferric salt solution One of or in which several mixed liquors.

6. a kind of layered double-hydroxide according to claim 5 loads the preparation method of biological carbon composite, special Sign is in the trivalent aluminium salt solution that trivalent aluminium salt is AlCl₃、Al₂(SO₄)₃Or Al (NO₃)₂·9H₂O；The trivalent Chromic salt is Cr (NO in chromium salt solution₃)₃、CrCl₃·6H₂O or Cr₂(SO₄)₃·6H₂O；Three in the ferric salt solution Valence molysite is FeCl₃·6H₂O、Fe(NO₃)₃·9H₂O or Fe₂(SO₄)₃。

7. a kind of layered double-hydroxide according to claim 5 loads the preparation method of biological carbon composite, special Levying the buffer solution described in being step 1 2. is NaOH, Na₂CO₃With the mixed liquor of water；NaOH in the buffer solution Concentration is 0.1mol/L~1mol/L, Na₂CO₃Concentration be 0.1mol/L~1mol/L.

8. a kind of layered double-hydroxide according to claim 1 loads the preparation method of biological carbon composite, special Sign is that inert gas described in step 2 is nitrogen or argon gas.

9. a kind of layered double-hydroxide according to claim 1 loads the preparation method of biological carbon composite, special Sign is in step 2 that heating rate when tube furnace being warming up to 500 DEG C~700 DEG C under inert gas protection is 8 DEG C/min ~12 DEG C/min.

10. a kind of layered double-hydroxide according to claim 1 loads the preparation method of biological carbon composite, special Sign is that pyrolysis time described in step 2 is 0.5~2h.