CN115739025A - Magnesium-iron modified corn straw biochar and preparation method and application thereof - Google Patents
Magnesium-iron modified corn straw biochar and preparation method and application thereof Download PDFInfo
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- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 title claims abstract description 86
- 235000002017 Zea mays subsp mays Nutrition 0.000 title claims abstract description 86
- 235000005822 corn Nutrition 0.000 title claims abstract description 86
- MHKWSJBPFXBFMX-UHFFFAOYSA-N iron magnesium Chemical compound [Mg].[Fe] MHKWSJBPFXBFMX-UHFFFAOYSA-N 0.000 title claims abstract description 67
- 239000010902 straw Substances 0.000 title claims abstract description 63
- 238000002360 preparation method Methods 0.000 title claims abstract description 21
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 60
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- 239000011574 phosphorus Substances 0.000 claims abstract description 37
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 32
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 30
- 239000002689 soil Substances 0.000 claims abstract description 20
- 238000001179 sorption measurement Methods 0.000 claims abstract description 20
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- 239000000843 powder Substances 0.000 claims abstract description 13
- 229910052742 iron Inorganic materials 0.000 claims abstract description 12
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 12
- 238000000034 method Methods 0.000 claims abstract description 8
- ZIZOLPLDZMECCR-UHFFFAOYSA-J magnesium;iron(2+);tetrahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[Mg+2].[Fe+2] ZIZOLPLDZMECCR-UHFFFAOYSA-J 0.000 claims abstract description 7
- 239000000243 solution Substances 0.000 claims description 45
- 239000011259 mixed solution Substances 0.000 claims description 21
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 18
- 238000006243 chemical reaction Methods 0.000 claims description 13
- 239000003513 alkali Substances 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 7
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- 239000003795 chemical substances by application Substances 0.000 claims description 3
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- 238000004321 preservation Methods 0.000 claims description 3
- 239000011777 magnesium Substances 0.000 abstract description 18
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 abstract description 11
- GDVKFRBCXAPAQJ-UHFFFAOYSA-A dialuminum;hexamagnesium;carbonate;hexadecahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Al+3].[Al+3].[O-]C([O-])=O GDVKFRBCXAPAQJ-UHFFFAOYSA-A 0.000 abstract description 8
- 229960001545 hydrotalcite Drugs 0.000 abstract description 8
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- 235000013619 trace mineral Nutrition 0.000 abstract description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052799 carbon Inorganic materials 0.000 abstract description 3
- 239000003610 charcoal Substances 0.000 abstract description 3
- 239000013078 crystal Substances 0.000 abstract description 3
- 239000000463 material Substances 0.000 abstract description 3
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- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 abstract description 2
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- 125000000524 functional group Chemical group 0.000 description 2
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- PJNZPQUBCPKICU-UHFFFAOYSA-N phosphoric acid;potassium Chemical compound [K].OP(O)(O)=O PJNZPQUBCPKICU-UHFFFAOYSA-N 0.000 description 2
- -1 phosphorus ions Chemical class 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
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- 239000002351 wastewater Substances 0.000 description 2
- 239000002028 Biomass Substances 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 229910019089 Mg-Fe Inorganic materials 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
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Images
Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P60/00—Technologies relating to agriculture, livestock or agroalimentary industries
- Y02P60/20—Reduction of greenhouse gas [GHG] emissions in agriculture, e.g. CO2
- Y02P60/21—Dinitrogen oxide [N2O], e.g. using aquaponics, hydroponics or efficiency measures
Abstract
The invention provides magnesium-iron modified corn straw biochar and a preparation method and application thereof, and belongs to the technical field of biochar materials. The invention uses magnesium and iron as a modifier, and the magnesium and iron are trace elements required by plant growth, thereby not only obviously improving the adsorption capacity of the biochar to nitrogen and phosphorus and providing nitrogen and phosphorus nutrition for plants, but also supplementing the magnesium and iron trace elements in soil. The invention uses the corn stalk powder as the charcoal carbon source, which has high specific surface area, is beneficial to fixing magnesium and iron and improving the adsorption capacity of nitrogen and phosphorus, and simultaneously has the advantages of wide source and low price; according to the invention, magnesium and iron are fixed on the surface of the biochar in a hydroxide precipitation manner by a coprecipitation method, and a layered magnesium-iron hydroxide (hydrotalcite) crystal can be formed under the condition that the pH value is 10 to 12, so that the adsorption sites of nitrogen and phosphorus are obviously increased, and the specific surface area and the surface potential of the biochar are increased, thereby improving the adsorption capacity of nitrogen and phosphorus.
Description
Technical Field
The invention relates to the technical field of biochar materials, and particularly relates to magnesium-iron modified corn straw biochar and a preparation method and application thereof.
Background
The nitrogen and phosphorus elements are essential nutrient elements for crop growth, and for a long time, in order to improve crop yield, the nitrogen and phosphorus chemical fertilizers in China are too much in dosage, so that the utilization rate of the chemical fertilizers is low, and excessive nitrogen and phosphorus which are not utilized enter a water environment, so that water eutrophication is caused, and an ecological system is damaged. Biochar is a carbon-rich material produced by the pyrolysis of waste biomass under oxygen-limited conditions. The biochar can absorb nitrogen and phosphorus which are not absorbed by crops in soil due to a unique porous structure, a specific surface area and rich surface functional groups. However, the conventional biochar is often poor in adsorption capacity for nitrogen and phosphorus ions, and the reason for this is mainly that the conventional biochar is often electronegative and is difficult to adsorb nitrogen and phosphorus anions through electrostatic adsorption.
The existing research shows that the modification of the biochar can increase the specific surface area and the porosity of the biochar, change the type and the number of functional groups on the surface of the biochar and form new compounds and nano particles on the surface of the biochar. Patent CN 112090404A discloses a preparation method of modified corn straw biochar and application thereof in phosphorus-containing wastewater. This method uses FeCl 3 As a core modifier, when the obtained modified corn straw biochar is used for removing phosphorus in phosphorus-containing wastewater, PO is removed 4 3- The maximum adsorption capacity of the adsorbent is only 5.7mg/g, and the adsorption capacity of the adsorbent can not meet the use requirement of soil.
Disclosure of Invention
In view of the above, the invention aims to provide magnesium-iron modified corn straw biochar and a preparation method and application thereof. The magnesium-iron modified corn straw biochar provided by the invention has high adsorption capacity on nitrogen and phosphorus.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of magnesium-iron modified corn straw biochar, which comprises the following steps:
pyrolyzing the corn straw powder to obtain corn straw biochar;
mixing the corn straw biochar with the magnesium-iron mixed solution to obtain a premixed solution; the magnesium-iron mixed solution contains Mg 2+ And Fe 3+ ；
And adding an inorganic strong base solution into the premixed solution to enable the pH value of the premixed solution to be 10-12, and carrying out coprecipitation reaction to obtain the magnesium-iron modified corn straw biochar.
Preferably, the temperature of the pyrolysis is 300 to 750 ℃, and the heat preservation time is 1 to 2.5 hours.
Preferably, in the magnesium-iron mixed solution, mg 2+ The concentration of (b) is 0.03 to 0.3 mol/L, fe 3+ The concentration of (b) is 0.01 to 0.1 mol/L; in the magnesium-iron mixed solution, mg 2+ With Fe 3+ The molar ratio of (b) to (c) is 2 to 5.
Preferably, the volume ratio of the mass of the corn straw biochar to the magnesium-iron mixed solution is 0.25-10 g:100 And (mL).
Preferably, the inorganic strong alkali solution is a NaOH solution and/or a KOH solution, and the concentration of the inorganic strong alkali solution is 0.1 to 1 mol/L.
Preferably, the temperature of the coprecipitation reaction is 20 to 40 ℃, and the time is 30 to 120 min.
Preferably, the grain diameter of the corn stalk powder is 0.125 to 4.75 mm; the grain size of the corn stalk biochar is less than or equal to 2 mu m.
The invention provides magnesium-iron modified corn straw biochar prepared by the preparation method, which comprises corn straw biochar and magnesium-iron hydroxide loaded on the surface and internal pores of the corn straw biochar.
The invention provides an application of the magnesium-iron modified corn straw biochar as a nitrogen and phosphorus adsorption fixing agent for soil.
Preferably, the dosage of the magnesium-iron modified corn stalk biochar in soil is 0.02 to 0.2 t/hm 2 。
The invention provides a preparation method of magnesium-iron modified corn straw biochar, which comprises the following steps: pyrolyzing the corn straw powder to obtain corn straw biochar; mixing the corn straw biochar with the magnesium-iron mixed solution to obtain a premixed solution; the magnesium-iron mixed solution contains Mg 2+ And Fe 3+ (ii) a And adding an inorganic strong base solution into the premixed solution to enable the pH value of the premixed solution to be 10, and carrying out coprecipitation reaction to obtain the magnesium-iron modified corn straw biochar. The invention uses magnesium and iron as a modifier, and the magnesium and iron are trace elements required by plant growth, thereby not only obviously improving the adsorption capacity of the biochar to nitrogen and phosphorus and providing nitrogen and phosphorus nutrition for plants, but also supplementing the magnesium and iron trace elements in soil. The invention uses the corn stalk powder as the biochar carbon source, has high specific surface area, is beneficial to fixing magnesium and iron and improving the adsorption capacity of nitrogen and phosphorus, and simultaneously has the advantages of wide source, low price and reproducibility; according to the invention, magnesium and iron are fixed on the surface of the biochar in a hydroxide precipitation manner by a coprecipitation method, and layered magnesium-iron hydroxide (hydrotalcite) crystals can be formed under the condition that the pH value is 10 to 12, so that the adsorption sites of nitrogen and phosphorus are obviously increased, and the specific surface area and the surface potential of the biochar are increased, thereby improving the adsorption capacity of nitrogen and phosphorus. The embodiment result shows that the magnesium-iron modified corn straw biochar can reduce leaching of 54.08% of nitrogen in soil, can completely inhibit leaching of phosphorus in the soil, and has obviously higher adsorption capacity on nitrogen and phosphorus than common biochar.
Drawings
FIG. 1 is an SEM image of magnesium-iron modified corn stalk biochar obtained in example 1;
FIG. 2 is a graph of the ratio of the leaching nitrogen to the applied nitrogen in example 1;
FIG. 3 is the ratio of leaching phosphorus to phosphorus applied in example 2;
FIG. 4 shows the adsorption capacity of phosphorus for different samples tested in comparative example 1.
Detailed Description
The invention provides a preparation method of magnesium-iron modified corn straw biochar, which comprises the following steps:
pyrolyzing the corn straw powder to obtain corn straw biochar;
mixing the corn straw biochar with the magnesium-iron mixed solution to obtain a premixed solution; the magnesium-iron mixed solution contains Mg 2+ And Fe 3+ ；
And adding an inorganic strong base solution into the premixed solution to enable the pH value of the premixed solution to be 10-12, and carrying out coprecipitation reaction to obtain the magnesium-iron modified corn straw biochar.
In the invention, the grain diameter of the corn stalk powder is preferably 0.125 to 4.75 mm, and more preferably 0.5 to 3 mm. In the present invention, the method for preparing corn stalk powder preferably comprises the following steps:
and (3) sequentially air-drying, crushing and sieving the natural corn straw to obtain the corn straw powder.
The present invention does not require any particular operation for said air-drying, crushing and sieving, and can be carried out using the above-mentioned operations well known to those skilled in the art.
In the present invention, the pyrolysis is preferably carried out in a muffle furnace; in the present invention, the temperature of the pyrolysis is preferably 300 to 750 ℃, and more preferably 400 to 600 ℃; the heat preservation time is preferably 1 to 2.5 hours, and more preferably 1.5 to 2 hours. In the present invention, the pyrolysis is preferably carried out under oxygen-limited conditions, the oxygen-limited conditions preferably having an oxygen content of 1% by volume or less.
In the invention, the grain diameter of the corn stalk biochar is preferably less than or equal to 2 mu m.
The corn straw biochar is mixed with the magnesium-iron mixed solution to obtain the premixed solution. In the invention, the magnesium-iron mixed solution contains Mg 2+ And Fe 3+ Said Mg 2+ The concentration of (b) is preferably 0.03 to 0.3 mol/L, and more preferably 0.1 to 0.2 mol/L; fe 3+ The concentration of (b) is preferably 0.01 to 0.1 mol/L, more preferably 0.04 to 0.06 mol/L. In the invention, in the magnesium-iron mixed solution, mg 2+ With Fe 3+ The molar ratio of (b 1) to (c) is preferably 2 to 5, more preferably 3 to 4.
In the present invention, the soluble source of magnesium used to prepare the premix is preferably MgCl 2 And/or MgSO 4 (ii) a The soluble iron source used to prepare the premix is preferably FeCl 3 And/or Fe 2 (SO 4 ) 3 。
The volume ratio of the mass of the corn straw biochar to the magnesium-iron mixed solution is preferably 0.25-10g: 100mL, more preferably 1 to 5g:100mL.
The invention does not require any particular mixing means, such as stirring, known to the person skilled in the art.
Adding an inorganic strong alkali solution into the premixed solution to enable the pH value of the premixed solution to be 10-12, and carrying out coprecipitation reaction to obtain the magnesium-iron modified corn straw biochar.
In the present invention, the inorganic strong alkali solution is preferably a NaOH solution and/or a KOH solution; the concentration of the inorganic alkali solution is preferably 0.1 to 1 mol/L, and more preferably 0.4 to 0.8 mol/L. In the present invention, the inorganic strong alkali solution is preferably added under stirring.
In the present invention, the coprecipitation reaction is preferably carried out under stirring. In the invention, the temperature of the coprecipitation reaction is preferably 20 to 40 ℃, and more preferably 25 to 35 ℃; the time is preferably 30 to 120 min, more preferably 60 to 90 min. In the invention, the stirring speed is preferably 60 to 200 r/min, and more preferably 100 to 150 r/min.
After the coprecipitation reaction, the present invention preferably performs a post-treatment on the obtained coprecipitation reaction product, and the post-treatment preferably includes the following steps:
and carrying out solid-liquid separation on the coprecipitation reaction product, and washing and drying the obtained solid ethylene to obtain the magnesium-iron modified corn straw biochar.
In the present invention, the solid-liquid separation is preferably centrifugation; the washing liquid used for washing is preferably deionized water; the drying mode is preferably drying.
The invention provides magnesium-iron modified corn straw biochar prepared by the preparation method, which comprises corn straw biochar and magnesium-iron hydroxide loaded on the surface and the internal pores of the corn straw biochar, wherein the magnesium-iron hydroxide is preferably hydrotalcite with a lamellar structure.
In the invention, the load capacity of the magnesium-iron hydroxide in the magnesium-iron modified corn straw biochar is preferably 5-10wt%, and more preferably 6-8wt%.
The invention provides application of the magnesium-iron modified corn straw biochar as a soil nitrogen and phosphorus adsorption fixing agent.
In the invention, the preferable dosage of the magnesium-iron modified corn straw biochar in soil is 0.02 to 0.2 t/hm 2 More preferably 0.05 to 0.15 t/hm 2 。
In the present invention, the method of application preferably comprises the steps of:
applying the magnesium-iron modified corn straw biochar to soil and ploughing.
In the invention, the application mode of the magnesium-iron modified corn straw biochar is preferably broadcast application.
In the invention, after the plowing, the modified corn straw biochar is preferably positioned to a depth of 0-20cm in soil.
The magnesium-iron modified corn stalk biochar provided by the invention and the preparation method and application thereof are described in detail in the following with reference to the examples, but the magnesium-iron modified corn stalk biochar cannot be understood as limiting the protection scope of the invention.
Example 1
(1) Preparation of magnesium-iron modified corn straw biochar
Placing the corn stalk scraps which are 100 meshes in a muffle furnace, heating to 600 ℃, pyrolyzing for 1.5 h, cooling, taking out, crushing and sieving; adding 10g of charcoal powder with particle size less than 2 μm into 1L of Mg 2+ Has a concentration of 0.3 mol/L, fe 3+ The magnesium-iron mixed solution with the concentration of 0.10 mol/L is stirred evenly at the temperature of 25 ℃, 1 mol/L NaOH solution is added while stirring, the pH value is adjusted to 10, the coprecipitation reaction is carried out for 60 min under the stirring condition, and the solution is separated and separatedWashing with sub-water, and drying to obtain the magnesium-iron modified corn straw biochar.
The SEM image of the obtained magnesium-iron modified corn stalk biochar is shown in figure 1. As can be seen from FIG. 1, typical layered magnesium iron hydrotalcite crystals are formed on the surface of the biochar.
(2) Nitrogen leaching experiment
Mixing the magnesium-iron modified corn straw biochar (marked as LB group) with soil according to the mass ratio of 0.5%, and culturing at room temperature (25 +/-0.5 ℃) in a dark and ventilated place. After 24 hours, 100 g of the above-mentioned treated soil was uniformly packed in a column by a wet packing method. 50 mL of ultrapure water is firstly dropped into the column at a constant speed. Then, 80 mL of 50 mg L were added -1 And (3) uniformly dropping a urea solution (regarded as a nitrogen solution) into the column, immediately collecting the leaching solution, filtering, and determining the content of nitrogen. The test was run with an additional blank (CK) and raw biochar (B) control. The ratio of the leaching nitrogen to the administered nitrogen is shown in fig. 2. Through calculation, compared with a control, the magnesium-iron modified corn straw biochar can reduce leaching of 54.08% of nitrogen in soil, and is remarkably higher than common biochar.
Example 2
(1) Preparation of magnesium-iron modified corn straw biochar
Placing the corn stalk scraps which are 100 meshes in a muffle furnace, heating to 600 ℃, pyrolyzing for 1.5 h, cooling, taking out, crushing and sieving; adding 10g of charcoal powder with particle size less than 2 μm into 1L of Mg 2+ Has a concentration of 0.3 mol/L, fe 3+ The magnesium-iron mixed solution with the concentration of 0.10 mol/L is uniformly stirred at the temperature of 30 ℃, 1 mol/L NaOH solution is added while stirring, the pH value is adjusted to 10, coprecipitation reaction is carried out for 45 min under the stirring condition, deionized water is used for cleaning, and drying is carried out, so as to obtain the magnesium-iron modified corn straw biochar.
(2) Phosphorus leaching experiment
Mixing the magnesium-iron modified corn straw biochar with soil according to the mass ratio of 0.5%, placing the mixture in a dark and ventilated place, and culturing at room temperature (25 +/-0.5 ℃). After 24 hours, 100 g of the above-mentioned treated soil was uniformly packed in a column by a wet packing method. 50 mL of ultrapure water is dripped into the column at a constant speed. Then, 80 mL of 60 mg L were added -1 Dropping potassium dihydrogen phosphate solution (as phosphorus solution) into the column at constant speed, collecting the leaching solution immediately, filtering, and measuring phosphorus content. The test was run with additional control of blank (CK) and raw biochar (B). The ratio of leaching phosphorus to the phosphorus applied is shown in figure 3. The result shows that the magnesium-iron modified corn straw biochar can completely inhibit leaching of phosphorus in soil.
Comparative example 1
(1) Preparation of common corn stalk biochar
And putting the corn straw scraps which are 100 meshes in a muffle furnace, heating to 600 ℃ for pyrolysis for 1.5 h, cooling, taking out, crushing, sieving, washing with deionized water, and drying to obtain the common corn straw biochar.
(2) Preparation of magnesium iron hydrotalcite
Preparing 1L of Mg-Fe mixed solution, mg 2+ Has a concentration of 0.3 mol/L, fe 3+ Adding 1 mol/L NaOH solution at 25 ℃, stirring while adding, adjusting the pH to 10, carrying out coprecipitation reaction for 60 min under the stirring condition, washing with deionized water, and drying to obtain the magnesium-iron hydrotalcite.
(3) Phosphorus adsorption experiment
0.10 g of common corn straw biochar, 0.10 g of magnesium-iron hydrotalcite and 0.01g of magnesium-iron modified corn straw biochar prepared in the example 1 are taken as samples to be detected and respectively mixed with 50 mL of potassium dihydrogen phosphate solution in a 150 mL glass triangular flask. After being sealed by a sealing film, the triangular flask is placed in a track oscillation incubator, the phosphorus content is measured after 24 hours at the rotating speed of 120 rpm, the test result is shown in figure 4, and as can be seen from figure 4, the adsorption capacity of the common corn straw biochar and the magnesium-iron hydrotalcite on phosphorus is obviously lower than that of the magnesium-iron modified corn straw biochar.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (8)
1. The preparation method of the magnesium-iron modified corn straw biochar is characterized by comprising the following steps:
pyrolyzing the corn straw powder to obtain corn straw biochar; the pyrolysis temperature is 300 to 750 ℃, and the heat preservation time is 1 to 2.5 hours;
mixing the corn straw biochar with the magnesium-iron mixed solution to obtain a premixed solution; the magnesium-iron mixed solution contains Mg 2+ And Fe 3+ ；
Adding an inorganic strong base solution into the premixed solution to enable the pH value of the premixed solution to be 10 to 12, and carrying out coprecipitation reaction to obtain magnesium-iron modified corn straw biochar; the temperature of the coprecipitation reaction is 20 to 40 ℃, and the time is 30 to 120 min.
2. The method according to claim 1, wherein Mg is contained in the mixed solution of Mg and Fe 2+ The concentration of (b) is 0.03 to 0.3 mol/L, fe 3+ The concentration of (b) is 0.01 to 0.1 mol/L; in the magnesium-iron mixed solution, mg 2+ With Fe 3+ The molar ratio of (a) to (b) is 2 to 5.
3. The preparation method of the biochar as claimed in claim 2, wherein the volume ratio of the mass of the biochar from the corn stalks to the magnesium-iron mixed solution is 0.25-10 g:100 And (mL).
4. The preparation method according to claim 1, wherein the inorganic alkali solution is a NaOH solution and/or a KOH solution, and the concentration of the inorganic alkali solution is 0.1 to 1 mol/L.
5. The preparation method of claim 1, wherein the corn stalk powder has a particle size of 0.125 to 4.75 mm; the grain size of the corn stalk biochar is less than or equal to 2 mu m.
6. The magnesium-iron modified corn stalk biochar prepared by the preparation method of any one of claims 1 to 5 is characterized by comprising corn stalk biochar and magnesium-iron hydroxide loaded on the surface and internal pores of the corn stalk biochar.
7. The application of the magnesium-iron modified corn stalk biochar disclosed by claim 6 as a soil nitrogen and phosphorus adsorption fixing agent.
8. The application of claim 7, wherein the amount of the magnesium-iron modified corn stalk biochar in soil is 0.02 to 0.2 t/hm 2 。
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Citations (3)
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| CN109513424A (en) * | 2018-12-17 | 2019-03-26 | 中南大学 | A kind of carbon/hydrotalcite compound adsorbent and its preparation, application and regeneration method in heavy metal adsorption |
| CN112007609A (en) * | 2020-08-27 | 2020-12-01 | 桂林理工大学 | Preparation method and application of Fe-Mg/mulberry stalk biochar composite material |
| CN115155543A (en) * | 2022-05-19 | 2022-10-11 | 浙江科技学院 | Method for preparing magnetic magnesium-iron LDH-biochar composite material in one step and application |
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| CN109513424A (en) * | 2018-12-17 | 2019-03-26 | 中南大学 | A kind of carbon/hydrotalcite compound adsorbent and its preparation, application and regeneration method in heavy metal adsorption |
| CN112007609A (en) * | 2020-08-27 | 2020-12-01 | 桂林理工大学 | Preparation method and application of Fe-Mg/mulberry stalk biochar composite material |
| CN115155543A (en) * | 2022-05-19 | 2022-10-11 | 浙江科技学院 | Method for preparing magnetic magnesium-iron LDH-biochar composite material in one step and application |
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