A water treatment material for removing lead from wastewater and its preparation method and application

Abstract

The invention belongs to the technical field of water treatment materials, and discloses a water treatment material for removing lead from wastewater, a preparation method and an application thereof. The preparation method comprises: drying grapevines and bagasse, crushing them, mixing them to obtain a mixed powder; placing the mixed powder in a medium containing Fe 3+ The solution is stirred and solid-liquid separated to obtain a precursor material; the precursor material is carbonized under a nitrogen atmosphere, ground into powder, fly ash and alkali metal hydroxide are added and mixed, and activated to obtain porous modified biochar; sodium alginate solution is used as an embedding agent and CaCl2 solution is used as a cross-linking agent to gel embed the porous modified biochar, and after freeze drying, the water treatment material for wastewater lead removal is obtained. The preparation method of the present invention is simple to operate, and the prepared water treatment material can effectively adsorb lead ions and has excellent renewable and reusable performance, which is conducive to promotion and large-scale use.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment materials, and in particular to a water treatment material for removing lead from wastewater, and a preparation method and application thereof. Background Art

[0002] At present, the heavy metal pollution situation in my country is becoming increasingly serious, especially the lead ion pollution problem. Excessive lead ion absorption by crops will affect their growth and yield; and lead ions are non-biodegradable, which will cause them to accumulate in animals and plants, thereby causing various diseases. Its persistence and toxicity have become one of the main pollutants in water resources. Therefore, it is urgent to solve the problem of lead ion pollution in the water environment.

[0003] In the prior art, the most commonly used methods for removing lead ions in wastewater include electrolysis, ion exchange, membrane separation and adsorption. Among them, adsorption is widely used due to its simple operation, wide application range, no secondary pollution, fast reaction speed, economy, good selectivity, and the advantages of easy design and operation. And the commonly used adsorbents in the prior art include activated carbon, fly ash, magnetic graphene, chitosan, etc., but when removing lead ions in water, due to the low actual effective specific surface area, the lead ion removal effect is poor and the adsorption treatment time is long, which is not conducive to promoting large-scale use. In addition, in order to improve the adsorption material with high specific surface area, those skilled in the art consider using metal organic framework materials (MOFs) as adsorbents to remove lead ions in wastewater, but the stability and selectivity of metal organic framework materials (MOFs) are poor, and lead ions in wastewater cannot be removed efficiently.

[0004] To this end, the present invention provides a water treatment material for removing lead from wastewater, and a preparation method and application thereof. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a water treatment material for removing lead from wastewater, and a preparation method and application thereof.

[0006] The water treatment material for removing lead from wastewater and its preparation method and application of the present invention are achieved through the following technical solutions:

[0007] The first object of the present invention is to provide a method for preparing a water treatment material for removing lead from wastewater, comprising the following steps:

[0008] Step 1, drying grape vines and sugarcane bagasse respectively and then crushing them to obtain grape vine powder and sugarcane bagasse powder; and mixing the grape vine powder and sugarcane bagasse powder to obtain a mixed powder;

[0009] Step 2: placing the mixed powder in a 3+The solution is stirred and solid-liquid separated to obtain a precursor material;

[0010] Step 3, carbonizing the precursor material under a nitrogen atmosphere to obtain modified biochar;

[0011] Step 4, grinding the modified biochar into powder, adding fly ash and alkali metal hydroxide to mix, and performing activation treatment to obtain porous modified biochar;

[0012] Step 5: Using sodium alginate solution as embedding agent, CaCl 2 The solution is a cross-linking agent, and the porous modified biochar is subjected to gel embedding treatment. After freeze-drying, the water treatment material for removing lead from wastewater is obtained.

[0013] Furthermore, the mixed powder and the Fe-containing 2+ The solution dosage ratio is 1g:15~25mL;

[0014] And the Fe-containing 3+ Fe in solution 3+ The concentration is 0.8~1.2mol / L.

[0015] Furthermore, the mass ratio of the grapevine powder to the bagasse powder is 0.5-1.5:1.

[0016] Furthermore, the mass ratio of the fly ash, alkali metal hydroxide and modified biochar is 1-3:0.2-0.5:1.

[0017] Furthermore, the stirring treatment temperature is 65-75° C., and the stirring time is 20-60 min.

[0018] Furthermore, the mass concentration of the sodium alginate solution is 2-4%; and the usage ratio of the sodium alginate solution to the modified biochar is 10 mL: 1-3 g.

[0019] Furthermore, the CaCl 2 The mass concentration of the solution is 2-4%.

[0020] Furthermore, the carbonization process is as follows:

[0021] First, heat the mixture to 300-400°C at a heating rate of 5-10°C / min and keep it at that temperature for 1-2h. Then, heat the mixture to 500-600°C at a heating rate of 10-15°C / min and keep it at that temperature for 1-2h. Then, cool the mixture to room temperature.

[0022] Further, the gel embedding process is carried out by the following steps:

[0023] S1, uniformly dispersing the porous modified biochar in the sodium alginate solution to obtain solution A;

[0024] S2. At a temperature of 3-5°C, inject the solution A into the CaCl 2 In the solution, gel microspheres were obtained;

[0025] S3, the gel microspheres were placed at room temperature for 0.5 to 1.5 hours, washed, and then CaCl 2 The solution immerses the surface of the microspheres, and then cross-links the microspheres at a temperature of 3 to 5° C. for 18 to 24 hours. The microspheres are taken out, washed and dried to obtain the water treatment material for removing lead from wastewater.

[0026] The second object of the present invention is to provide a water treatment material prepared by the above preparation method.

[0027] The third object of the present invention is to provide an application of the above-mentioned water treatment material in removing lead ions from wastewater.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention uses grapevine powder and bagasse powder as carbon sources, and soaks them in Fe-containing 3+ In the solution, since both grapevine powder and bagasse powder have rich plant fibers and pore structures, they can easily load Fe 3+ , and then obtain Fe 3+ The carbon source, i.e. the precursor material, is then carbonized. During the carbonization process, the grapevine powder and sugarcane bagasse powder are converted into biochar, and the Fe 3+ ions are converted to Fe 3 O 4 (Maybe Fe 2 O 3 ), and obtain iron-modified modified biochar, wherein Fe 3 O 4It has magnetic properties, which helps to separate the water treatment material from the water phase better, so that it can be quickly recovered. Then, the modified biochar is further modified by using fly ash and alkali metal hydroxide as the second modifier, wherein the fly ash contains a large amount of porous glass, presents a porous honeycomb structure, has a large specific surface area, and has a large number of active groups such as Si-O-Si bonds and Al-O-Al bonds on its surface, and has a high adsorption activity. In addition, the alkali metal hydroxide can not only further activate the modified biochar, but also assist the fly ash to generate a large number of new fine pores under high temperature conditions, increase the specific surface area and porosity, provide more sites for binding lead ions, and effectively adsorb lead ions, thereby contributing to its adsorption performance. In addition, the present invention can further improve the adsorption capacity of the material by coating the gel material on the surface of the biochar, while improving the renewable and reusable performance of the material.

[0030] The preparation method of the present invention is simple to operate, and the prepared water treatment material can effectively adsorb lead ions and has excellent renewable and reusable performance, which is conducive to promotion and large-scale use. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below.

[0032] The present invention provides a water treatment material for removing lead from wastewater, and the preparation method thereof is as follows:

[0033] Step 1, drying grape vines and sugarcane bagasse respectively and then crushing them to obtain grape vine powder and sugarcane bagasse powder; and mixing the grape vine powder and sugarcane bagasse powder to obtain a mixed powder;

[0034] It should be noted that the present invention uses grapevine and sugarcane bagasse as carbon sources, which can not only alleviate the pressure and pollution problems caused by the accumulation of agricultural waste on the environment, but also realize the recycling of resources and reduce production costs. In addition, grapevine powder and sugarcane bagasse powder both have rich plant fibers and pore structures, which are convenient for loading Fe 3+ Modification treatment is carried out to facilitate the introduction of Fe 3 O 4 Magnetic molecules such as argon and argon can help to separate the water treatment material from the water phase, so that it can be quickly recycled, solving the problem of biochar powder being difficult to recycle in the prior art. In the present invention, the mass ratio of the grapevine powder to the sugarcane bagasse powder is preferably 0.5 to 1.5:1.

[0035] The drying temperature is 55-75°C and the drying time is 4-8 hours. 3+ For loading, preferably, both grapevine and bagasse are crushed to 80 mesh.

[0036] Step 2: placing the mixed powder in a 3+ The solution is stirred and solid-liquid separated to obtain a precursor material;

[0037] It should be noted that the present invention is to make Fe 3+ The mixed powder and the Fe-containing 3+ The solution dosage ratio is 1g:15-25mL; and the Fe-containing 3+ Fe in solution 3+ The concentration is 0.8-1.2 mol / L. The preferred stirring temperature is 65-75°C, the stirring rate is 200-400 r / min, and the stirring time is 20-60 min.

[0038] Step 3, carbonizing the precursor material under a nitrogen atmosphere to obtain modified biochar;

[0039] It should be noted that the present invention firstly performs carbonization treatment on the precursor material, so that during the carbonization process of the precursor material, the grapevine powder and the sugarcane bagasse powder are converted into biochar, and the Fe 3+ ions are converted to Fe 3 O 4 (Maybe Fe 2 O 3 ), and obtain iron-modified modified biochar, wherein Fe 3 O 4 The magnetic property helps to separate the water treatment material from the water phase, so that it can be quickly recovered. The preferred carbonization process is: firstly heat up to 300-400℃ at a heating rate of 5-10℃ / min and keep it for 1-2h, then heat up to 500-600℃ at a heating rate of 10-15℃ / min and keep it for 1-2h, and then cool to room temperature.

[0040] Step 4, grinding the modified biochar into powder, adding fly ash and alkali metal hydroxide to mix, and performing activation treatment to obtain porous modified biochar;

[0041] It should be noted that in order to enable the modified biochar to fully contact with fly ash and alkali metal hydroxides, the modified biochar needs to be ground into powder before mixing with fly ash and alkali metal hydroxides to avoid the formation of too large blocks in the previous carbonization treatment, which leads to the inability to fully contact with fly ash and alkali metal hydroxides. Preferably, the modified biochar is ground to pass through a 100-mesh sieve.

[0042] The present invention uses fly ash and alkali metal hydroxide as the second modifier to further modify the modified biochar, wherein the fly ash contains a large amount of porous glass, presents a porous honeycomb structure, has a large specific surface area, and has a large amount of active groups such as Si-O-Si bonds and Al-O-Al bonds on its surface, and has a high adsorption activity. In addition, the alkali metal hydroxide can not only further activate the modified biochar, but also assist the fly ash to generate a large number of new fine pores under high temperature conditions, increase the specific surface area and porosity, provide more sites for binding lead ions, effectively adsorb lead ions, and thus contribute to its adsorption performance.

[0043] Step 5: Using sodium alginate solution as embedding agent, CaCl 2 The solution is a cross-linking agent, and the porous modified biochar is subjected to gel embedding treatment, and after freeze drying, the water treatment material for removing lead from wastewater is obtained;

[0044] It should be noted that the present invention can further improve the adsorption capacity of the material by coating the gel material on the surface of the biochar, while improving the renewable and reusable performance of the material. The present invention specifically performs gel embedding treatment by the following steps: S1, uniformly dispersing the porous modified biochar in the sodium alginate solution to obtain solution A; S2, injecting the solution A into the CaCl 2 solution to obtain gel microspheres; S3, placing the gel microspheres at room temperature for 0.5 to 1.5 hours, washing, and then adding CaCl 2 The solution immerses the surface of the microspheres, and then cross-links the microspheres at a temperature of 3 to 5° C. for 18 to 24 hours. The microspheres are taken out, washed, and freeze-dried to obtain the water treatment material for removing lead from wastewater.

[0045] It should also be noted that all freeze-drying processes involved in the present invention are: freezing temperature is -45 to -55°C, and the time is 12 to 60 hours.

[0046] Then, the preparation method of the present invention is simple to operate, and the prepared water treatment material can effectively adsorb lead ions and has excellent renewable and reusable performance, which is conducive to promotion and large-scale use.

[0047] Example 1

[0048] This embodiment provides a water treatment material for removing lead from wastewater, and the preparation method thereof is as follows:

[0049] Step 1, drying grape vines and sugarcane bagasse respectively and then crushing them to obtain grape vine powder and sugarcane bagasse powder; and mixing the grape vine powder and sugarcane bagasse powder to obtain a mixed powder;

[0050] The drying temperature is 60° C. and the drying time is 6 hours; and the particle sizes of the grapevine powder and the bagasse powder are both sieved through an 80-mesh sieve.

[0051] In this embodiment, the mass ratio of the grapevine powder to the bagasse powder is 1:1.

[0052] Step 2, placing the mixed powder in a 1.1 mol / L ferric chloride solution, stirring at 70° C. and a stirring rate of 300 r / min for 40 min, filtering, and obtaining a precursor material;

[0053] In this embodiment, the dosage ratio of the mixed powder to the ferric chloride solution is 1 g:20 mL.

[0054] Step 3, carbonizing the precursor material in a nitrogen atmosphere, first heating the temperature to 350° C. at a heating rate of 7° C. / min and keeping the temperature for 1.5 h, then heating the temperature to 550° C. at a heating rate of 12° C. / min and keeping the temperature for 1.5 h, and then cooling the temperature to room temperature to obtain modified biochar;

[0055] Step 4, grinding the modified biochar into powder, passing it through a 100-mesh sieve to obtain biochar powder, then adding fly ash and sodium hydroxide to mix, and performing activation treatment to obtain porous modified biochar;

[0056] In this embodiment, the mass ratio of fly ash, sodium hydroxide and the biochar is 2:0.3:1.

[0057] Step 5: Using sodium alginate solution as embedding agent, CaCl 2 The solution is a cross-linking agent, and the porous modified biochar is subjected to gel embedding treatment, and after drying, the water treatment material for removing lead from wastewater is obtained;

[0058] In this embodiment, the gel embedding process is performed by the following steps:

[0059] S1. Evenly dispersing the porous modified biochar in a sodium alginate solution with a mass concentration of 3% to obtain solution A; wherein the amount ratio of the sodium alginate solution to the porous modified biochar is 10 mL: 2 g;

[0060] S2. At a temperature of 4°C, inject the solution A into a 4% CaCl 2 In the solution, gel microspheres were obtained;

[0061] S3, the gel microspheres were placed at room temperature for 1 hour, washed, and then CaCl with a mass concentration of 3% was added. 2 The surface of the microspheres is immersed in the solution, and then cross-linked at a temperature of 4° C. for 20 hours. The microspheres are taken out, washed, and dried at 60° C. for 3 hours to obtain the water treatment material for removing lead from wastewater.

[0062] Example 2

[0063] This embodiment provides a water treatment material for removing lead from wastewater, and the preparation method thereof is as follows:

[0064] Step 1, drying grape vines and sugarcane bagasse respectively and then crushing them to obtain grape vine powder and sugarcane bagasse powder; and mixing the grape vine powder and sugarcane bagasse powder to obtain a mixed powder;

[0065] The drying temperature is 55° C. and the drying time is 4 hours; and the particle sizes of the grapevine powder and the sugarcane bagasse powder are both 80 mesh sieves.

[0066] In this embodiment, the mass ratio of the grapevine powder to the sugarcane bagasse powder is 0.5:1.

[0067] Step 2, placing the mixed powder in a 0.8 mol / L ferric chloride solution, stirring at 65° C. and a stirring rate of 200 r / min for 20 min, filtering, and obtaining a precursor material;

[0068] In this embodiment, the dosage ratio of the mixed powder to the ferric chloride solution is 1 g:15 mL.

[0069] Step 3, carbonizing the precursor material in a nitrogen atmosphere, first heating the temperature to 300° C. at a heating rate of 5° C. / min and keeping the temperature for 1 to 2 hours, then heating the temperature to 500° C. at a heating rate of 10° C. / min and keeping the temperature for 1 hour, and then cooling the temperature to room temperature to obtain modified biochar;

[0070] Step 4, grinding the modified biochar into powder, passing it through a 100-mesh sieve to obtain modified biochar powder, then adding fly ash and sodium hydroxide to mix, and performing activation treatment to obtain porous modified biochar;

[0071] In this embodiment, the mass ratio of fly ash, sodium hydroxide and the modified biochar is 1:0.2:1.

[0072] Step 5: Using sodium alginate solution as embedding agent, CaCl 2 The solution is a cross-linking agent, and the porous modified biochar is subjected to gel embedding treatment, and after drying, the water treatment material for removing lead from wastewater is obtained;

[0073] In this embodiment, the gel embedding process is performed by the following steps:

[0074] S1. Evenly dispersing the porous modified biochar in a sodium alginate solution with a mass concentration of 2% to obtain solution A; wherein the amount ratio of the sodium alginate solution to the porous modified biochar is 10 mL: 1 g;

[0075] S2. At a temperature of 3°C, inject the solution A into a 2% CaCl 2 In the solution, gel microspheres were obtained;

[0076] S3, the gel microspheres were placed at room temperature for 0.5 h, washed, and then CaCl with a mass concentration of 2% was added. 2 The surface of the microspheres is immersed in the solution, and then cross-linked at a temperature of 3° C. for 18 hours. The microspheres are taken out, washed, and dried at 55° C. for 2 hours to obtain the water treatment material for removing lead from wastewater.

[0077] Example 3

[0078] This embodiment provides a water treatment material for removing lead from wastewater, and the preparation method thereof is as follows:

[0079] Step 1, drying grape vines and sugarcane bagasse respectively and then crushing them to obtain grape vine powder and sugarcane bagasse powder; and mixing the grape vine powder and sugarcane bagasse powder to obtain a mixed powder;

[0080] The drying temperature is 65° C. and the drying time is 8 hours; and the particle sizes of the grapevine powder and the sugarcane bagasse powder are both 80 mesh sieves.

[0081] In this embodiment, the mass ratio of the grapevine powder to the bagasse powder is 1.5:1.

[0082] Step 2, placing the mixed powder in a 1.2 mol / L ferric chloride solution, stirring at 75° C. and a stirring rate of 400 r / min for 60 min, filtering, and obtaining a precursor material;

[0083] In this embodiment, the dosage ratio of the mixed powder to the ferric chloride solution is 1 g:25 mL.

[0084] Step 3, carbonizing the precursor material in a nitrogen atmosphere, first heating the temperature to 400° C. at a heating rate of 10° C. / min and keeping the temperature for 2 h, then heating the temperature to 600° C. at a heating rate of 15° C. / min and keeping the temperature for 2 h, and then cooling the temperature to room temperature to obtain biochar;

[0085] Step 3, grinding the biochar into powder, passing it through a 100-mesh sieve to obtain biochar powder, then adding fly ash and potassium hydroxide to mix, and performing activation treatment to obtain modified biochar;

[0086] In this embodiment, the mass ratio of fly ash, potassium hydroxide and the biochar is 3:0.5:1.

[0087] Step 4: Using sodium alginate solution as embedding agent, CaCl 2The solution is a cross-linking agent, and the modified biochar is subjected to gel embedding treatment, and after drying, the water treatment material for removing lead from wastewater is obtained;

[0088] In this embodiment, the gel embedding process is performed by the following steps:

[0089] S1. Evenly dispersing the modified biochar in a sodium alginate solution with a mass concentration of 4% to obtain solution A; wherein the amount ratio of the sodium alginate solution to the modified biochar is 10 mL:3 g;

[0090] S2. At a temperature of 5°C, inject the solution A into a 4% CaCl 2 In the solution, gel microspheres were obtained;

[0091] S3, the gel microspheres were placed at room temperature for 1.5 h, washed, and then CaCl with a mass concentration of 4% was added. 2 The surface of the microspheres is immersed in the solution, and then cross-linked at a temperature of 5° C. for 24 hours. The microspheres are taken out, washed, and dried at 65° C. for 4 hours to obtain the water treatment material for removing lead from wastewater.

[0092] Comparative Example 1

[0093] This comparative example provides a water treatment material for removing lead from wastewater, and the difference between it and Example 1 is only that:

[0094] In this comparative example, fly ash and sodium hydroxide are not added for modification.

[0095] Comparative Example 2

[0096] This comparative example provides a water treatment material for removing lead from wastewater, and the difference between it and Example 1 is only that:

[0097] This comparative example did not undergo gel embedding treatment.

[0098] Comparative Example 3

[0099] This embodiment provides a water treatment material for removing lead from wastewater, and the difference between this material and Embodiment 1 is only that:

[0100] This comparative example does not use Fe 3+ The solution is modified, that is, the mixed powder is directly carbonized.

[0101] Comparative Example 4

[0102] This embodiment provides a water treatment material for removing lead from wastewater, and the difference between this material and Embodiment 1 is only that:

[0103] In this comparative example, only bagasse powder was used as the carbon source.

[0104] Experimental part

[0105] The present invention uses a certain industrial waste liquid as the waste liquid to be treated. After testing, the concentration of lead ions therein is 8.58 mg / L.

[0106] In the present invention, the water treatment materials prepared in Example 1 and Comparative Examples 1-3 are used as adsorbents, 20 g of each is placed in 1 L of the above-mentioned waste liquid to be treated, the pH is adjusted to 6, and stirred at a speed of 150 r / min for 60 min at room temperature. After solid-liquid separation, the lead ion concentration is detected, the lead ion removal rate is calculated and recorded as shown in Table 1.

[0107] It should be noted that the lead ion concentration detection and removal rate calculation in the present invention are as follows: the lead ion concentration in the waste liquid is measured according to the "Determination of 32 Elements in Water Quality by Inductively Coupled Plasma Emission Spectrometry" (HJ 776-2015). The lead ion removal rate is calculated according to the following formula: Among them, R Pb is the lead ion removal rate, c Pb0 is the initial concentration of lead ions in the wastewater before disposal (mg / L), c Pbt is the lead ion concentration in the treated wastewater (mg / L).

[0108] Table 1 Lead ion removal rate

[0109]

[0110]

[0111] The present invention uses the water treatment material prepared in Example 1 as an adsorbent, places it in the above-mentioned 1L of waste liquid to be treated, adjusts the pH to 6, and stirs and adsorbs it at a speed of 150r / min at room temperature for 60min. After the adsorption is completed, it is washed with ethanol 3 times for desorption, and then placed in a drying oven at a temperature of 60°C for 4h, and then used for adsorption of lead ions again, and the desorption and regeneration are repeated 5 times to perform 5 adsorption-desorption experimental tests. It can be seen from the test that the lead ion removal rates of the five times are 94.1%, 93.8%, 91.4%, 89.1%, and 85.6%, respectively, indicating that the water treatment material prepared in Example 1 has a reduced adsorption capacity for lead ions, but is still not less than 90% of the initial adsorption effect, indicating that the water treatment material prepared in the present invention has good desorption and regeneration performance.

[0112] Obviously, the above embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A method for preparing a water treatment material for removing lead from wastewater, characterized in that: The following steps are involved: Step 1, drying grape vines and sugarcane bagasse respectively and then crushing them to obtain grape vine powder and sugarcane bagasse powder; and mixing the grape vine powder and sugarcane bagasse powder to obtain a mixed powder; Step 2: placing the mixed powder in a 3+ The solution is stirred and solid-liquid separated to obtain a precursor material; Step 3, carbonizing the precursor material under a nitrogen atmosphere to obtain modified biochar; Step 4, grinding the modified biochar into powder, adding fly ash and alkali metal hydroxide to mix evenly, and performing activation treatment to obtain porous modified biochar; Step 5, using sodium alginate solution as an embedding agent and CaCl2 solution as a cross-linking agent, performing gel embedding treatment on the porous modified biochar, and after freeze-drying, obtaining the water treatment material for wastewater lead removal; The stirring temperature is 65-75°C and the stirring time is 20-60min; The gel embedding process is carried out by the following steps: S1, uniformly dispersing the porous modified biochar in the sodium alginate solution to obtain solution A; S2, injecting the solution A into a CaCl2 solution at a temperature of 3 to 5°C to obtain gel microspheres; S3. Place the gel microspheres at room temperature for 0.5 to 1.5 hours, wash them, add a CaCl2 solution to immerse their surface, and then cross-link them at a temperature of 3 to 5°C for 18 to 24 hours. Take out the microspheres, wash them, and freeze-dry them to obtain the water treatment material for removing lead from wastewater.

2. The preparation method according to claim 1, characterized in that The mixed powder and the Fe-containing 3+ The solution dosage ratio is 1g:15~25mL; And the Fe-containing 3+ Fe in solution 3+ The concentration is 0.8~1.2mol / L.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the grapevine powder to the bagasse powder is 0.5-1.5:

1.

4. The preparation method according to claim 1, characterized in that: The mass ratio of the fly ash, the alkali metal hydroxide and the modified biochar is 1-3:0.2-0.5:

1.

5. The preparation method according to claim 1, characterized in that: The mass concentration of the sodium alginate solution is 2-4%; and the dosage ratio of the sodium alginate solution to the porous modified biochar is 10 mL: 1-3 g; The mass concentration of the CaCl2 solution is 2-4%.

6. The preparation method according to claim 1, characterized in that: The process of the carbonization treatment is: First, heat the mixture to 300-400°C at a heating rate of 5-10°C / min and keep it at that temperature for 1-2h. Then, heat the mixture to 500-600°C at a heating rate of 10-15°C / min and keep it at that temperature for 1-2h. Then, cool the mixture to room temperature.

7. A water treatment material prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the water treatment material according to claim 7 in removing lead ions from wastewater.