Soil conditioner suitable for riverside plains and fertilizer containing the soil conditioner

Abstract

The invention discloses a soil conditioner suitable for riverside plains and a fertilizer containing the soil conditioner, in the technical field of functional fertilizers. A porous, high-strength hard biochar is obtained by carbonizing high-strength coconut fiber and macroporous adsorption resin, the strength of the biochar as a matrix is ​​improved, magnetic ferroferric oxide is hydrothermally synthesized on the surface of the biochar through carboxyl groups, and a porous skeleton centered on lanthanum is further synthesized to fix lanthanum and magnetic ferroferric oxide, thereby improving the adsorption of heavy metals; the resin is interspersed in the magnetic porous lanthanized biochar, and the introduction of the large specific surface area of ​​the resin can expand the pore size distribution and provide more adsorption sites. The resin itself has viscosity and water absorption. When interspersed in the biochar, the binding force between the biochar and soil particles can be further enhanced, which is helpful to stabilize the soil structure and reduce the loss of soil water.

Description

Technical Field

[0001] The invention belongs to the technical field of functional fertilizers, and in particular relates to a soil conditioner suitable for plains along a river and a fertilizer containing the soil conditioner. Background Art

[0002] In the plain areas along the river, under suitable climate and farming conditions, the soil has high fertility and is rich in organic matter and various nutrients, such as nitrogen, phosphorus, potassium, etc., which provide sufficient nutrients for the growth of crops. The plain areas along the river have abundant water resources and excellent irrigation conditions, which are conducive to crop growth and agricultural production, and provide a good soil environment for rice growth.

[0003] With the acceleration of industrialization and urbanization, industrial wastewater, domestic sewage, agricultural non-point source pollution, etc. are continuously discharged into the soil and water bodies, resulting in the enhanced bioavailability of heavy metals in the soil, further increasing the absorption and enrichment of heavy metals by rice. During the enrichment process, heavy metals will enter the root system of the plant, and then be transported to other parts such as stems, leaves, and grains through the root system, thereby affecting the quality and yield of rice. Rice contaminated by heavy metals will promote the accumulation of harmful substances, which will cause harm to human health through the food chain.

[0004] Chinese patent application CN117004395A discloses a method for preparing a zeolite-supported iron-lanthanum soil arsenic pollution remediation agent and its application, by mixing Fe and Lanthanum in equal volume proportions. 3+ Solution and La 3+ The solution is stirred evenly to obtain an iron-lanthanum composite reactant, the zeolite is immersed in a NaCl solution to obtain a modified zeolite, the modified zeolite is added to the iron-lanthanum composite reactant, ultrasonically mixed and then oscillated, but ultrasonic mixing cannot achieve uniform and stable loading of iron and lanthanum on the modified zeolite, and the adsorption effect cannot be effectively exerted. Summary of the invention

[0005] The purpose of the present invention is to provide a soil conditioner suitable for plains along the river. A porous and high-strength hard biochar is obtained by carbonization, magnetic ferroferric oxide is hydrothermally synthesized on the surface of the biochar through carboxyl groups, and a porous skeleton centered on lanthanum is further synthesized to achieve the fixation of lanthanum and ferroferric oxide, improve the utilization rate, and improve the adsorption of heavy metals. Resin is interspersed in the magnetic porous lanthanized biochar to expand the pore size distribution and provide more adsorption sites, thereby enhancing the adsorption capacity of heavy metals. When the biochar is evenly mixed with dolomite powder, calcium magnesium phosphate fertilizer, organic fertilizer and microbial composite bacterial agent and used as a fertilizer, the acidification of the soil can be significantly reduced.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A fertilizer containing a soil conditioner for riverside plains is prepared by the following steps:

[0008] Measured by mass, 20-25 parts of soil conditioner, 10-12 parts of dolomite powder, 2-3 parts of calcium magnesium phosphate fertilizer, 1-2 parts of organic fertilizer and 1-2 parts of microbial compound agent are added into a blender and mixed evenly to obtain a fertilizer suitable for the soil in the plain along the river.

[0009] Furthermore, the soil conditioner is prepared by the following steps:

[0010] Step 1: Add coconut fiber with a length of 3-5 cm and 50-60% ethanol solution into a reactor, stir for 24-26 hours at 20-25° C. and 500-600 r / min, place in an oven at 100-110° C. for drying for 30-40 minutes, transfer to a mixed solution of 0.3-0.5% sulfuric acid and 0.2-0.4% nitric acid, stir for 30-40 minutes at 60-70° C. and 500-600 r / min, filter, wash the filter cake with deionized water until neutral, vacuum dry at 60-80° C. for 1-2 hours, crush, and pass through a 120-140 mesh sieve to obtain pretreated coconut fiber.

[0011] Step 2: Add polystyrene, divinylbenzene, pretreated coconut fiber and deionized water into the reactor, stir for 40-60 min at 20-25 ° C and 500-600 r / min, add isooctane as a porogen, benzoyl peroxide as an initiator and sodium dodecylbenzene sulfonate as a dispersant into the reactor, stir for 8-10 h at 60-70 ° C and 400-500 r / min, filter, wash the filter cake with deionized water 3-4 times, vacuum dry at 60-80 ° C to constant weight, crush, pass through a 180-200 mesh sieve, transfer to a muffle furnace, pass nitrogen protection, heat to 600-700 ° C at a rate of 5-6 ° C / min, keep warm for 2-3 h, heat to 1000-1200 ° C at a rate of 9-10 ° C / min, keep warm for 2-3 h, cool naturally, and obtain porous hard biochar particles.

[0012] Step 3: Add ferric chloride hexahydrate, sodium citrate and ethylene glycol to the reactor, stir at 40-50°C and 500-600r / min for 20-30min, add sodium acetate and porous hard biochar particles to the reactor, heat to 90-100°C, continue stirring for 4-5h, cool naturally, filter, wash the filter cake with deionized water 2-3 times, and vacuum dry at 60-80°C for 1-2h to obtain magnetic biochar.

[0013] Step 4: Add magnetic biochar, 5-hydroxyisophthalic acid and deionized water into the reactor, dissolve sodium hexadecyl sulfate as a surfactant in 70-75% ethanol solution and add it into the reactor, stir for 1-2 hours at 50-60°C and 400-500r / min, add 5-6kg of lanthanum chloride into the reactor, continue stirring and reacting for 4-5 hours, filter, wash the filter cake with deionized water and anhydrous ethanol for 2-3 times respectively, and vacuum dry at 60-80°C for 16-18 hours to obtain a magnetic porous lanthanized biochar powder with a particle size of 20-30μm.

[0014] Step 5: Add 4-hydroxybutyl vinyl ether, N,N-dimethylformamide and deionized water into the reactor, stir at 40-50°C and 500-600r / min for 20-30min, then add divinylbenzene, magnetic porous lanthanide biochar powder, gelatin powder as a dispersant and benzoyl peroxide as an initiator into the reactor, add sodium hydroxide and acetic acid dropwise to adjust the pH value to 6.5-7, heat to 80-90°C, stir at 500-600r / min for 2-3h, cool naturally, filter, wash the filter cake with deionized water for 2-3 times, and vacuum dry at 60-80°C for 1-2h to obtain a soil conditioner suitable for the plain along the river.

[0015] Furthermore, in step 1, the usage ratio of coconut fiber, ethanol solution, sulfuric acid and nitric acid is 10-12kg: 8-9L: 15-16L: 5-8L.

[0016] Furthermore, in step 2, the usage ratio of polystyrene, divinylbenzene, pretreated coconut fiber, deionized water, isooctane, benzoyl peroxide and sodium dodecylbenzene sulfonate is 5-6kg:2-3L:8-10kg:9-12L:200-300mL:200-300mL:150-180mL.

[0017] Furthermore, in step three, the usage ratio of ferric chloride hexahydrate, sodium citrate, ethylene glycol, sodium acetate and porous hard biochar particles is 7-8kg: 1-2kg: 7-8L: 1-2kg: 5-6kg.

[0018] Furthermore, in step 4, the usage ratio of magnetic biochar, 5-hydroxyisophthalic acid, deionized water, sodium hexadecyl sulfate, ethanol solution and lanthanum chloride is 5-6kg:3-4kg:5-6L:500-600g:3-4L:5-6kg.

[0019] Furthermore, in step five, the usage ratio of 4-hydroxybutyl vinyl ether, N,N-dimethylformamide, deionized water, divinylbenzene, magnetic porous lanthanized biochar powder, gelatin powder and benzoyl peroxide is 5-6kg:1-2L:4-5L:5-6kg:4-5kg:500-600g:800-900g.

[0020] Beneficial effects of the present invention:

[0021] 1. The soil conditioner prepared by the present invention can significantly absorb heavy metal fluorine and arsenic in the soil, reduce the biological effectiveness of heavy metals in the soil, and improve the farming environment of crops in the plain areas along the river; when it is evenly mixed with dolomite powder, calcium magnesium phosphate fertilizer, organic fertilizer and microbial composite bacterial agent and used as a fertilizer, it can significantly reduce the acidification of the soil, alleviate the stickiness of the soil texture, increase the permeability of the soil, and improve the fertility of the soil.

[0022] 2. The magnetic porous lanthanized biochar powder of the present invention hydrothermally synthesizes magnetic ferrosoferric oxide through carboxyl functional groups on the surface of porous hard biochar particles. The introduction of carboxyl functional groups improves the interfacial bonding force between ferrosoferric oxide and biochar. With biochar as the matrix, the dispersibility and stability of ferrosoferric oxide are significantly improved, the agglomeration of ferrosoferric oxide is prevented, and the adsorption efficiency of ferrosoferric oxide is improved. The carboxyl groups on the surface of the magnetic biochar are chemically bonded with the monomer 5-hydroxyisophthalic acid, and a porous skeleton centered on lanthanum is hydrothermally synthesized on its surface. The porous lanthanum skeleton can improve the utilization rate of lanthanum and further improve the strength of the magnetic biochar. The porous nature of the porous lanthanum skeleton further improves the adsorption effect of the soil conditioner on heavy metals.

[0023] 3. The soil conditioner of the present invention is prepared by inserting cationic adsorption resin into magnetic porous lanthanized biochar. The porous hard biochar causes cross-linking and entanglement between coconut fiber and macroporous adsorption resin through physical adsorption, and is carbonized under the action of porogen and high temperature. The soil conditioner has good stability. The high-strength and high-stable spatial structure helps the resin to avoid being compressed in the soil and fully absorb water and swell, thereby ensuring the adsorption effect and making it more durable in the soil. The large specific surface area of ​​the cationic adsorption resin can expand the pore size distribution of the overall material and provide more adsorption sites, thereby enhancing the adsorption capacity for pollutants. The cationic adsorption resin itself has certain viscosity and water absorption. When inserted into biochar, it can further enhance the binding force between biochar and soil particles and further improve the utilization rate of lanthanum. The enhancement of this binding force helps to stabilize the soil structure and reduce soil water loss. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the 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.

[0025] Example 1: A soil conditioner suitable for the plain along the river and a fertilizer containing the soil conditioner are prepared by the following steps:

[0026] S1: Add 10 kg of coconut fiber with a length of 3-5 cm and 8 L of 50% ethanol solution into a reactor, stir at 20°C and 500 r / min for 24 h, place in an oven at 100°C for 30 min, transfer to a mixed solution of 15 L of 0.3% sulfuric acid and 5 L of 0.2% nitric acid, stir at 60°C and 500 r / min for 30 min, filter, wash the filter cake with deionized water until neutral, dry at 60°C in vacuum for 1 h, crush, and pass through a 120-mesh sieve to obtain pretreated coconut fiber.

[0027] S2: 5 kg of polystyrene, 2 L of divinylbenzene, 8 kg of pretreated coconut fiber and 9 L of deionized water were added into the reactor, stirred at 20 °C and 500 r / min for 40 min, 200 mL of isooctane as a porogen, 200 mL of benzoyl peroxide as an initiator and 150 mL of sodium dodecylbenzene sulfonate as a dispersant were added into the reactor, stirred at 60 °C and 400 r / min for 8 h, filtered, the filter cake was washed with deionized water for 3 times, vacuum dried at 60 °C to constant weight, crushed, passed through a 180 mesh sieve, transferred to a muffle furnace, passed nitrogen protection, heated to 600 °C at a rate of 5 °C / min, kept warm for 2 h, heated to 1000 °C at a rate of 9 °C / min, kept warm for 2 h, cooled naturally, and porous hard biochar particles were obtained.

[0028] The macroporous adsorption resin molecules are adsorbed on the surface of coconut fiber by physical action, and the coconut fiber molecules are cross-linked and entangled with the macroporous adsorption resin molecules. Under the action of the porogen and high temperature, they are carbonized into hard biochar with porosity and high strength.

[0029] S3: Add 7kg of ferric chloride hexahydrate, 1kg of sodium citrate and 7L of ethylene glycol into the reactor, stir at 40℃ and 500r / min for 20min, add 1kg of sodium acetate and 5kg of porous hard biochar particles into the reactor, heat to 90℃, continue stirring for 4h, cool naturally, filter, wash the filter cake twice with deionized water, and vacuum dry at 60℃ for 1h to obtain magnetic biochar.

[0030] Carboxylated magnetic ferroferric oxide was hydrothermally synthesized on the surface of porous hard biochar particles. When ferroferric oxide was loaded on the surface of biochar, the carrier effect of biochar could improve the dispersibility and stability of ferroferric oxide, prevent its agglomeration, and improve the adsorption efficiency.

[0031] S4: 5 kg of magnetic biochar, 3 kg of 5-hydroxyisophthalic acid and 5 L of deionized water were added into the reactor. 500 g of sodium hexadecyl sulfate as a surfactant was dissolved in 3 L of 70% ethanol solution and added into the reactor. The mixture was stirred at 50 °C and 400 r / min for 1 h. 5 kg of lanthanum chloride was added into the reactor. The mixture was stirred for 4 h. The mixture was filtered and the filter cake was washed twice with deionized water and anhydrous ethanol respectively. The mixture was dried at 60 °C in a vacuum oven for 16 h to obtain a magnetic porous lanthanized biochar powder with a particle size of 20 μm.

[0032] The carboxyl groups on the surface of magnetic biochar are chemically bonded with the monomer 5-hydroxyisophthalic acid, and a porous skeleton centered on lanthanum is hydrothermally synthesized on its surface. The porous lanthanum skeleton can improve the utilization rate of lanthanum and further improve the strength of magnetic biochar. The porous properties of the porous lanthanum skeleton can improve the adsorption of heavy metals by magnetic biochar in soil.

[0033] S5: Add 5kg 4-hydroxybutyl vinyl ether, 1L N,N-dimethylformamide and 4L deionized water into a reactor, stir at 40℃ and 500r / min for 20min, then add 5kg divinylbenzene, 4kg magnetic porous lanthanide biochar powder, 500g gelatin powder as a dispersant and 800g benzoyl peroxide as an initiator into the reactor, add sodium hydroxide and acetic acid dropwise to adjust the pH value to 6.5, heat to 80℃, stir at 500r / min for 2h, cool naturally, filter, wash the filter cake twice with deionized water, and dry it in vacuo at 60℃ for 1h to obtain a soil conditioner suitable for the plain along the river.

[0034] By interspersing the resin in the magnetic porous lanthanized biochar, the introduction of the resin's large specific surface area can expand the pore size distribution of the adsorbent and provide more adsorption sites, thereby enhancing the adsorption capacity of pollutants. The resin itself has a certain viscosity and cohesion. When interspersed in the biochar, it can further enhance the binding force between the biochar and soil particles and further improve the utilization rate of lanthanum. This enhanced binding force helps to stabilize the soil structure and reduce soil erosion and loss.

[0035] S6: Add 20kg soil conditioner, 10kg dolomite powder, 2kg calcium magnesium phosphate fertilizer, 1kg organic fertilizer and 1kg microbial compound agent into a mixer and mix well to obtain a fertilizer suitable for the soil in the plain along the river.

[0036] Example 2: A soil conditioner suitable for the plain along the river and a fertilizer containing the soil conditioner are prepared by the following steps:

[0037] S1: 11 kg of coconut fiber with a length of 3-5 cm and 8.5 L of 55% ethanol solution were added into a reactor, stirred at 23 ° C and 550 r / min for 25 h, placed in an oven at 105 ° C for 35 min, transferred to a mixed solution of 15.5 L of 0.4% sulfuric acid and 7 L of 0.3% nitric acid, stirred at 65 ° C and 550 r / min for 35 min, filtered, washed the filter cake with deionized water until neutral, vacuum dried at 70 ° C for 1.5 h, crushed, and passed through a 130-mesh sieve to obtain pretreated coconut fiber.

[0038] S2: 5.5 kg of polystyrene, 2.5 L of divinylbenzene, 8.5 kg of pretreated coconut fiber and 9.5 L of deionized water were added into the reactor, stirred at 23 ° C and 550 r / min for 50 min, 250 mL of isooctane as a porogen, 250 mL of benzoyl peroxide as an initiator and 170 mL of sodium dodecylbenzene sulfonate as a dispersant were added into the reactor, stirred at 65 ° C and 450 r / min for 9 h, filtered, the filter cake was washed with deionized water for 3 times, vacuum dried at 70 ° C to constant weight, crushed, passed through a 190 mesh sieve, transferred to a muffle furnace, passed nitrogen protection, heated to 650 ° C at a rate of 6 ° C / min, kept warm for 2.5 h, heated to 1100 ° C at a rate of 10 ° C / min, kept warm for 2.5 h, cooled naturally, and porous hard biochar particles were obtained.

[0039] S3: Add 7.5 kg of ferric chloride hexahydrate, 1.5 kg of sodium citrate and 7.5 L of ethylene glycol into the reactor, stir at 45 ° C and 550 r / min for 25 min, add 1.5 kg of sodium acetate and 5.5 kg of porous hard biochar particles into the reactor, heat to 95 ° C, continue stirring for 4.5 h, cool naturally, filter, wash the filter cake with deionized water 3 times, and vacuum dry at 70 ° C for 1.2 h to obtain magnetic biochar.

[0040] S4: 5.5 kg of magnetic biochar, 3.5 kg of 5-hydroxyisophthalic acid and 5.5 L of deionized water were added to the reactor, 550 g of sodium hexadecyl sulfate as a surfactant was dissolved in 3.5 L of 73% ethanol solution and added to the reactor, stirred at 55 ° C and 450 r / min for 1.5 h, 5.5 kg of lanthanum chloride was added to the reactor, and the stirring reaction was continued for 4.5 h. The filter cake was washed with deionized water and anhydrous ethanol for 3 times respectively, and vacuum dried at 70 ° C for 17 h to obtain a magnetic porous lanthanized biochar powder with a particle size of 25 μm.

[0041] S5: Add 5.5 kg 4-hydroxybutyl vinyl ether, 1.5 L N, N-dimethylformamide and 4.5 L deionized water into the reactor, stir at 45 ° C and 550 r / min for 25 min, then add 5.5 kg divinylbenzene, 4.5 kg magnetic porous lanthanide biochar powder, 550 g gelatin powder as a dispersant and 850 g benzoyl peroxide as an initiator into the reactor, add sodium hydroxide and acetic acid dropwise to adjust the pH value to 6.8, heat to 85 ° C, stir at 550 r / min for 2.5 h, cool naturally, filter, wash the filter cake with deionized water three times, and vacuum dry at 70 ° C for 1.5 h to obtain a soil conditioner suitable for the plain along the river.

[0042] S6: Add 22kg of soil conditioner, 11kg of dolomite powder, 2kg of calcium magnesium phosphate fertilizer, 2kg of organic fertilizer and 1kg of microbial compound agent into a blender and mix well to obtain a fertilizer suitable for the soil in the plain along the river.

[0043] Example 3: A soil conditioner suitable for the plain along the river and a fertilizer containing the soil conditioner are prepared by the following steps:

[0044] S1: 12 kg of coconut fiber with a length of 3-5 cm and 9 L of 60% ethanol solution were added into a reactor, stirred at 25 ° C and 600 r / min for 26 h, placed in an oven at 110 ° C for 40 min, transferred to a mixed solution of 16 L of 0.5% sulfuric acid and 8 L of 0.4% nitric acid, stirred at 70 ° C and 600 r / min for 40 min, filtered, washed the filter cake with deionized water until neutral, vacuum dried at 80 ° C for 2 h, crushed, and passed through a 140-mesh sieve to obtain pretreated coconut fiber.

[0045] S2: 6 kg of polystyrene, 3 L of divinylbenzene, 9 kg of pretreated coconut fiber and 12 L of deionized water were added into the reactor, stirred at 25 °C and 600 r / min for 60 min, 300 mL of isooctane as a porogen, 300 mL of benzoyl peroxide as an initiator and 180 mL of sodium dodecylbenzene sulfonate as a dispersant were added into the reactor, stirred at 70 °C and 500 r / min for 10 h, filtered, the filter cake was washed with deionized water 4 times, vacuum dried at 80 °C to constant weight, crushed, passed through a 200 mesh sieve, transferred to a muffle furnace, passed nitrogen protection, heated to 700 °C at a rate of 6 °C / min, kept warm for 3 h, heated to 1200 °C at a rate of 10 °C / min, kept warm for 3 h, cooled naturally, and porous hard biochar particles were obtained.

[0046] S3: Add 8kg of ferric chloride hexahydrate, 2kg of sodium citrate and 8L of ethylene glycol into the reactor, stir at 50℃ and 600r / min for 30min, add 2kg of sodium acetate and 6kg of porous hard biochar particles into the reactor, heat to 100℃, continue stirring for 5h, cool naturally, filter, wash the filter cake with deionized water 3 times, and vacuum dry at 80℃ for 2h to obtain magnetic biochar.

[0047] S4: 6 kg of magnetic biochar, 4 kg of 5-hydroxyisophthalic acid and 6 L of deionized water were added into the reactor. 600 g of sodium hexadecyl sulfate as a surfactant was dissolved in 4 L of 75% ethanol solution and added into the reactor. The mixture was stirred at 60 °C and 500 r / min for 2 h. 6 kg of lanthanum chloride was added into the reactor. The mixture was stirred for 5 h. The mixture was filtered and the filter cake was washed with deionized water and anhydrous ethanol for 3 times respectively. The mixture was dried under vacuum at 80 °C for 18 h to obtain a magnetic porous lanthanized biochar powder with a particle size of 30 μm.

[0048] S5: Add 6 kg 4-hydroxybutyl vinyl ether, 2 L N,N-dimethylformamide and 5 L deionized water into a reactor, stir at 50 ° C and 600 r / min for 30 min, then add 6 kg divinylbenzene, 5 kg magnetic porous lanthanide biochar powder, 600 g gelatin powder as a dispersant and 900 g benzoyl peroxide as an initiator into the reactor, add sodium hydroxide and acetic acid dropwise to adjust the pH value to 7, heat to 90 ° C, stir at 600 r / min for 3 h, cool naturally, filter, wash the filter cake with deionized water 3 times, and vacuum dry at 80 ° C for 2 h to obtain a soil conditioner suitable for the plain along the river.

[0049] S6: Add 25kg of soil conditioner, 12kg of dolomite powder, 3kg of calcium magnesium phosphate fertilizer, 2kg of organic fertilizer and 2kg of microbial compound agent into a mixer and mix well to obtain a fertilizer suitable for the soil in the plain along the river.

[0050] Comparative Example 1: Based on Example 3, the porous hard biochar particles in step S3 were replaced with commercially available biochar powder of the same mass, and the other steps remained unchanged to prepare fertilizer for the soil of the plain along the river.

[0051] Comparative Example 2: Based on Example 3, the magnetic biochar in step S4 is replaced by the porous hard biochar particles in step S2, and the other steps remain unchanged to prepare fertilizer for the soil in the plain along the river.

[0052] Comparative Example 3: Based on Example 3, the magnetic porous lanthanide biochar powder in step S5 is replaced by the magnetic biochar in step S3, and the other steps remain unchanged to prepare fertilizer for the soil in the plain along the river.

[0053] Comparative Example 4: Based on Example 3, the neutral porous lanthanized biochar powder in step S5 is directly used as a soil conditioner, and the other steps remain unchanged to prepare fertilizer for the soil in the plain along the river.

[0054] In the embodiments and comparative examples:

[0055] Coconut fiber was purchased from Qingdao Jifa New Materials Co., Ltd.

[0056] Gelatin powder was purchased from Hebei Fuwei Technology Co., Ltd.

[0057] Ethanol solution, sulfuric acid and nitric acid, ferric chloride hexahydrate, polystyrene, divinylbenzene, isooctane, benzoyl peroxide, sodium dodecylbenzene sulfonate, N,N-dimethylformamide, and 4-hydroxybutyl vinyl ether were purchased from Sigma-Aldrich.

[0058] The performance of the fertilizers for the riverside plain soil prepared in Examples 1 to 3 and Comparative Examples 1 to 3 was tested. The fertilizers for the riverside plain soil prepared by the present invention were spread on the surface of the test soil at an amount of 800 kg / mu. The test soil was the soil in the Wuhu Riverside Park area. Then, the test soil and the fertilizer spread thereon were plowed and stirred 3 times according to the plowing and stirring method. The plowing depth was 20 cm to obtain different test soil samples. A 20 cm tillage layer test soil sample was collected to test the initial pH value of the soil, and the pH value of the test soil sample after 3 months was tested.

[0059] Referring to the test method of the Soil Environmental Quality Standard, the fluorine content of different test samples was measured at the beginning and 6 months after the application of different fertilizers, so as to evaluate the fertilizer's ability to adsorb fluorine;

[0060] According to the test method of the Soil Environmental Quality Standard GB15618-2018, the arsenic content of different test soil samples was measured at the beginning and 6 months after the application of different fertilizers, so as to evaluate the adsorption capacity of fertilizers for arsenic;

[0061] Refer to the test method of "Soil Testing Part 4: Determination of Soil Bulk Density" (NY / T1121.4-2006) to test the bulk density of different test soil samples;

[0062] After applying fertilizer, different test soil samples were placed vertically in pure water for 8 hours. Then, different test soil samples were taken out, weighed and placed vertically on a grid. They were weighed every 1.5 hours at room temperature until the mass of the test soil sample no longer changed. The mass before water absorption and the mass after sufficient water absorption (water absorption = mass after sufficient water absorption - mass before water absorption) were recorded. Different test soil samples were tested in the same way 3 months after applying fertilizer, so as to evaluate the water absorption capacity of the test soil samples after applying different fertilizers, which was recorded as the water retention time (h).

[0063] The performance of the fertilizers prepared in Examples 1 to 3 and Comparative Examples 1 to 3 for the soil in the plain along the river was tested, and the results are shown in Table 1:

[0064] Table 1 Performance test results of soil fertilizers in the plain along the river

[0065]

[0066] It can be seen from Table 1 that the pH value and water retention time of the fertilizer soil of the riverside plain soil prepared in Examples 1 to 3 of the present invention are significantly better than those of the comparative example, and the fluorine, arsenic and soil bulk density are significantly lower than those of the comparative example. In Comparative Example 1, the porous hard biochar particles in step S3 are replaced with commercially available biochar powder of the same mass, and a porous, high-strength hard biochar cannot be obtained, so that its performance in various performance tests in the soil is reduced to varying degrees.

[0067] In Comparative Example 2, the magnetic biochar in step S4 is replaced by the porous hard biochar particles in step S2, and the magnetic ferrosoferric oxide cannot be hydrothermally synthesized on the surface through the carboxyl functional groups, which greatly affects the adsorption of heavy metals and has no obvious effect on other properties of the fertilizer. Therefore, the test results of several other performance items are not much different from those of Example 3.

[0068] In Comparative Example 3, based on Example 3, the magnetic porous lanthanide biochar powder in step S5 is replaced by the magnetic biochar in step S3, which makes it impossible to hydrothermally synthesize a lanthanum-centered porous skeleton on the surface, thereby affecting the adsorption of heavy metals. The results of several other performance tests are not much different from those of Example 3.

[0069] In Comparative Example 4, on the basis of Example 3, the neutral porous lanthanized biochar powder of step S5 is directly used as a soil conditioner. The resin cannot be interspersed in the magnetic porous lanthanized biochar, which reduces the adsorption sites and thus reduces the adsorption capacity for heavy metals. The resin itself has certain viscosity and water absorption. When interspersed in the biochar, it can further enhance the binding force between the biochar and the soil particles, further improve the utilization rate of lanthanum and ferrosoferric oxide, and the resin is not interspersed in the magnetic porous lanthanized biochar, which reduces the stabilizing effect of the fertilizer on the soil and further reduces the water retention capacity of the fertilizer on the soil.

[0070] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0071] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A soil conditioner suitable for the plains along the river, characterized in that: Prepared by the following steps: Step 1: Add magnetic biochar, 5-hydroxyisophthalic acid and deionized water into a reactor, dissolve sodium hexadecyl sulfate in 70-75wt% ethanol solution and add into the reactor, stir at 50-60°C and 400-500r / min for 1-2h, add lanthanum chloride into the reactor, continue stirring and reacting for 4-5h, filter, wash the filter cake with deionized water and anhydrous ethanol for 2-3 times respectively, and vacuum dry to obtain a magnetic porous lanthanized biochar powder with a particle size of 20-30μm; Step 2: Add 4-hydroxybutyl vinyl ether, N,N-dimethylformamide and deionized water into a reactor, stir at 40-50°C and 500-600r / min for 20-30min, then add divinylbenzene, magnetic porous lanthanide biochar powder, gelatin powder and benzoyl peroxide into the reactor, add sodium hydroxide and acetic acid dropwise to adjust the pH value to 6.5-7, heat to 80-90°C, stir at 500-600r / min for 2-3h, cool naturally, filter, wash the filter cake with deionized water for 2-3 times, and vacuum dry to obtain a soil conditioner suitable for the plain along the river; The magnetic biochar described in step 1 is prepared by the following steps: Add ferric chloride hexahydrate, sodium citrate and ethylene glycol into a reactor, stir at 40-50°C and 500-600r / min for 20-30min, add sodium acetate and porous hard biochar particles into the reactor, heat to 90-100°C, continue stirring for 4-5h, cool naturally, filter, wash the filter cake with deionized water 2-3 times, and vacuum dry to obtain magnetic biochar; The porous hard biochar particles are prepared by the following steps: Add polystyrene, divinylbenzene, pretreated coconut fiber and deionized water into a reactor, stir at 20-25°C and 500-600r / min for 40-60min, add isooctane, benzoyl peroxide and sodium dodecylbenzene sulfonate into the reactor, stir at 60-70°C and 400-500r / min for 8-10h, filter with suction, wash the filter cake with deionized water for 3-4 times, vacuum dry to constant weight, crush, pass through a 180-200 mesh sieve, transfer to a muffle furnace, introduce nitrogen protection, heat to 600-700°C at a rate of 5-6°C / min, keep warm for 2-3h, heat to 1000-1200°C at a rate of 9-10°C / min, keep warm for 2-3h, cool naturally, and obtain porous hard biochar particles; The pretreated coconut fiber is prepared by the following steps: Add coconut fiber with a length of 20-23 cm and 50-60wt% ethanol solution into a reactor, stir for 24-26 hours at 20-25° C. and 500-600 r / min, place in an oven at 100-110° C. for drying for 30-40 minutes, transfer to a mixed solution of 0.3-0.5wt% sulfuric acid and 0.2-0.4wt% nitric acid, stir for 30-40 minutes at 60-70° C. and 500-600 r / min, filter, wash the filter cake with deionized water until it is neutral, vacuum dry at 60-80° C. for 1-2 hours, crush, and pass through a 120-140 mesh sieve to obtain pretreated coconut fiber.

2. The soil conditioner suitable for the plain along the river according to claim 1, characterized in that: The usage ratio of the magnetic biochar, 5-hydroxyisophthalic acid, deionized water, sodium hexadecyl sulfate, ethanol solution and lanthanum chloride in step 1 is 5-6kg: 3-4kg: 5-6L: 500-600g: 3-4L: 5-6kg.

3. The soil conditioner suitable for the plain along the river according to claim 1, characterized in that: The usage ratio of 4-hydroxybutyl vinyl ether, N,N-dimethylformamide, deionized water, divinylbenzene, magnetic porous lanthanized biochar powder, gelatin powder and benzoyl peroxide in step 2 is 5-6kg: 1-2L: 4-5L: 5-6kg: 4-5kg: 500-600g: 800-900g.

4. The soil conditioner suitable for the plain along the river according to claim 1, characterized in that: The usage ratio of ferric chloride hexahydrate, sodium citrate, ethylene glycol, sodium acetate and porous hard biochar particles is 7-8kg: 1-2kg: 7-8L: 1-2kg: 5-6kg.

5. The soil conditioner suitable for the plain along the river according to claim 1, characterized in that: The usage ratio of the polystyrene, divinylbenzene, pretreated coconut fiber, deionized water, isooctane, benzoyl peroxide and sodium dodecylbenzene sulfonate is 5-6kg: 2-3L: 8-10kg: 9-12L: 200-300mL: 200-300mL: 150-180mL.

6. The soil conditioner suitable for the plain along the river according to claim 1, characterized in that: The usage ratio of the coconut fiber, the ethanol solution, the sulfuric acid and the nitric acid is 10-12kg: 8-9L: 15-16L: 5-8L.

7. A fertilizer, characterized in that The raw material comprises the soil conditioner suitable for the riverside plain as described in claim 1, which is prepared by the following steps: Measured by mass, 20-25 parts of soil conditioner, 10-12 parts of dolomite powder, 2-3 parts of calcium magnesium phosphate fertilizer, 1-2 parts of organic fertilizer and 1-2 parts of microbial compound agent are added into a blender and mixed evenly to obtain a fertilizer suitable for the soil in the plain along the river.

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