CN112409094A

Movatterモバイル変換

Info

Publication number: CN112409094A
Application number: CN202011353186.0A
Authority: CN
Inventors: 吉芳英; 张凯
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2020-11-27
Filing date: 2020-11-27
Publication date: 2021-02-26
Anticipated expiration: 2040-11-27
Also published as: CN112409094B

Abstract

Translated fromChinese

本发明公开了一种人粪水热炭基包膜尿素肥的制备方法，按照如下步骤制备：1)取三格化粪池第一池底部粪渣，自然风干后粉碎过筛，然后投加至水热反应釜中，设置升温速率为8‑12℃/min，进行水热反应得到水热炭；2)将制备的水热炭分散于乙二醇中，然后加入FeCl₃·6H₂O溶解，再加入无水乙酸钠，搅拌使其充分混合，超声分散后转移至反应釜中，密封反应，反应完后取出，冷却，磁分离出Fe₃O₄/水热炭，洗涤，冷冻干燥，研磨得到Fe₃O₄/水热炭，3)称取r‑聚谷氨酸溶解至冰乙酸的水溶液中得到粘接剂，将尿素经粉碎机粉碎后过筛，随后，称取尿素置于造粒机中，启动造粒机，转动过程中喷洒粘结剂，同时缓慢撒入Fe₃O₄/水热炭得到产品。

The invention discloses a preparation method of human excrement hydrothermal carbon-based coated urea fertilizer, which is prepared according to the following steps: 1) taking the manure residue at the bottom of the first tank of a three-grid septic tank, naturally air-drying it, crushing it and sieving it, and then adding In the hydrothermal reaction kettle, the heating rate is set to be 8-12 ℃/min, and the hydrothermal reaction is carried out to obtain hydrothermal charcoal; 2) the prepared hydrothermal charcoal is dispersed in ethylene glycol, and then FeCl₃ ·6H₂ O is added Dissolve, add anhydrous sodium acetate, stir to fully mix, ultrasonically disperse, transfer to the reaction kettle, seal the reaction, take out after the reaction, cool, magnetically separate Fe₃ O₄ /hydrothermal carbon, wash, freeze-dry , grind to obtain Fe₃ O₄ / hydrothermal charcoal, 3) take r-polyglutamic acid and dissolve it in the aqueous solution of glacial acetic acid to obtain a binder, sieve the urea after pulverizer pulverization, subsequently, take the urea and put it In the granulator, start the granulator, spray the binder during the rotation, and at the same time slowly sprinkle Fe₃ O₄ /hydrothermal charcoal to obtain the product.

Description

Human excrement hydrothermal carbon-based coated urea fertilizer and preparation method thereof

Technical Field

The invention relates to a human excrement hydrothermal carbon-based coated urea fertilizer and a preparation method thereof, belonging to the technical field of slow release fertilizers.

Background

Human excrement contains a large amount of organic substances and nutrient elements such as nitrogen, phosphorus and the like, and if the human excrement is directly discharged, serious water and soil pollution is caused, so that the overall ecological environment is influenced. At present, the problems of lack of harmless treatment of excrement, easy generation of cross infection, lack of disinfection facilities in sewage treatment facility construction and the like still exist in rural areas in China.

According to statistics, the utilization rate of chemical fertilizers of wheat, rice and corn in 2019 in China is far lower than that of countries in Europe and America, and is only 39.2%. In order to meet the nutritional requirements of crops, excessive application of chemical fertilizers and pesticides not only causes soil hardening, aggravation of acidification and serious salinization, but also causes extremely low utilization rate of fertilizers and serious waste, and a large amount of chemical fertilizers which are not absorbed by the crops lose surface runoff and eluvial water along with the land to cause eutrophication of water bodies. Meanwhile, the quality of agricultural products is reduced, and the land benefit of farmers is low. In recent years, the nitrogen fertilizer coated by the high molecular polymer material has better slow release effect, but the high molecular polymer has high preparation cost, is difficult to degrade and is easy to generate secondary pollution. Therefore, the finding of the slow-release membrane material with low consumption, high efficiency and environmental friendliness is of great significance. Meanwhile, the soil chromium pollution in partial areas is serious at present, particularly the Cr (VI) is 100 times of Cr (III), and the Cr (VI) poisoning degree is one of 8 heavy metal control indexes for soil environment quality evaluation in China. If the carbon-based fertilizer realizes the restoration of chromium-polluted soil while realizing the slow release of urea, the application of the fertilizer in the fields of agricultural production and soil restoration is greatly promoted.

The hydrothermal carbon is a black solid product which takes human and animal excreta, straws, sludge, kitchen waste and the like as raw materials, takes water as a solvent and a reaction medium, and takes carbon as a main body through hydrothermal reaction at the temperature of 150-375 ℃ and the autogenous pressure. Compared with the traditional high-temperature pyrolysis, the microwave-assisted heating technology has the characteristics of high efficiency, high yield, cleanness and the like, and the prepared sample has higher purity, wider particle size distribution and more uniform appearance by virtue of two functions of dipole polarization and ion conduction, is rich in oxygen-containing functional groups and can react with NH₄⁺、NO₃^-Has stronger adsorption capacity, can reduce the leaching loss of soil nutrients, and is a good material for preparing the slow release fertilizer. Research for preparing slow release fertilizer based on hydrothermal carbon at presentThe research is less.

Disclosure of Invention

In view of the above technical problems, a first object of the present invention is to provide a method for preparing a human excrement hydrothermal carbon-based coated urea fertilizer, and a second object of the present invention is to provide a human excrement hydrothermal carbon-based coated urea fertilizer obtained thereby. The high-strength chromium-contaminated soil remediation agent has high compressive strength and good wear resistance, improves the utilization rate of the fertilizer, and can realize remediation of chromium-contaminated soil.

In order to achieve the first purpose, the invention provides a preparation method of a carbon-based coated urea fertilizer prepared from human excrement and water, which is characterized by comprising the following steps:

1) preparing hydrothermal carbon, namely taking the excrement slag at the bottom of the first tank of the three-grid septic tank, naturally drying, crushing and sieving, then adding into a hydrothermal reaction kettle, setting the heating rate to be 8-12 ℃/min, carrying out hydrothermal reaction, pouring out supernatant after the reaction is finished, washing the mixture to be neutral by using deionized water, carrying out freeze drying, and grinding to obtain the hydrothermal carbon;

2)Fe₃O₄hydrothermal carbon preparation, dispersing the prepared hydrothermal carbon in ethylene glycol, and then adding FeCl₃·6H₂Dissolving O, adding anhydrous sodium acetate, stirring to mix thoroughly, ultrasonic dispersing, transferring to a reaction kettle, sealing for reaction, taking out, cooling, and magnetically separating out Fe₃O₄Hydrothermal charcoal, washing, freeze drying, grinding to obtain Fe₃O₄Hydrothermal charcoal, Fe₃O₄The mass fraction of (A) is 10% -25%;

3) preparing a hydrothermal carbon-based urea fertilizer: weighing r-polyglutamic acid, dissolving into glacial acetic acid water solution to obtain binder, pulverizing urea, sieving, weighing urea, placing into a granulator, starting the granulator, spraying binder during rotation, and slowly spraying Fe₃O₄And/or hydrothermal carbon, taking out after the particles are formed, drying to constant weight, and cooling to obtain the product.

In the step 1), the reaction is respectively kept at 140 ℃, 180 ℃ and 220 ℃ for 30-40min during the reaction.

In the step 1), the ratio of the human excrement slag to water added into the hydrothermal reaction kettle is 15-20g of the human excrement slag added into each 100mL of water.

In the step 2), the reaction temperature is 200-250 ℃.

In the scheme, the mass concentration of the r-polyglutamic acid solution is 0.1-0.3%.

In the above scheme, the volume concentration of glacial acetic acid in the glacial acetic acid aqueous solution is 1%.

In the above scheme, Fe₃O₄The mass ratio of the hydrothermal carbon to the urea is 0.2-0.3: 1.

In the scheme, the excrement residue and the urea are crushed and then are sieved by a 50-100-mesh sieve.

The second object of the present invention is achieved by: the human excrement hydrothermal carbon-based coated urea fertilizer is prepared by the preparation method of the human excrement hydrothermal carbon-based coated urea fertilizer.

The invention takes gamma-polyglutamic acid as a binder and Fe₃O₄The modified hydrothermal carbon-based urea fertilizer is prepared by using hydrothermal carbon as a carrier. Gamma-PGA (Gamma-PGA) has super-strong hydrophilicity, and water molecules can form a film on the surface of the Gamma-PGA to slow down the direct contact of the Gamma-PGA with the outside. Fe₃O₄The nano particles have paramagnetism, high specific surface area and active surface anchoring and adsorbing functional molecules, and change the characteristics of unstable granulation structure, poor water resistance and instant dispersion when meeting water of single hydrothermal carbon coated urea. The invention takes gamma-polyglutamic acid as a binder to construct Fe₃O₄The hydrothermal carbon-based urea fertilizer fully utilizes the characteristics of hydrophilicity, spatial structure and the like of r-polyglutamic acid to improve the efficient absorption of nutrients by crops, and simultaneously skillfully utilizes the advantages of high specific surface area, magnetic separation and the like of the modified hydrothermal carbon to achieve a good slow release effect, so that the yield of the crops can be improved by more than 25 percent compared with the common urea. Meanwhile, hexavalent chromium in the chromium-polluted soil can be converted into trivalent chromium with lower toxicity, and the chromium-polluted soil can be repaired.

Drawings

FIG. 1 is a photograph of a hydrothermal carbon-based urea fertilizer prepared according to the present invention.

FIG. 2 is an SEM image of hydrothermal charcoal.

FIG. 3 is an SEM image of a modified hydrothermal carbon-based urea fertilizer of the present invention.

Fig. 4 is a graph of the nitrogen release characteristics of a carbon-based fertilizer.

Fig. 5 is a magnetization curve of hydrothermal charcoal-based urea and modified hydrothermal charcoal-based urea fertilizers at 300K.

Detailed Description

The invention is further illustrated by the following examples:

example 1

A preparation method of a human excrement hydrothermal carbon-based coated urea fertilizer comprises the following steps:

1) preparing hydrothermal carbon, taking the excrement residue at the bottom of the first tank of the three-grid septic tank, naturally drying, crushing, sieving by a 50-100 mesh sieve, and then adding into a hydrothermal reaction kettle, wherein 15g of human excrement residue is added into every 100mL of water. Setting the heating rate to be 8 ℃/min, carrying out hydrothermal reaction, respectively staying at 140 ℃, 180 ℃ and 220 ℃ for 30min, pouring out supernatant after the reaction is finished, washing the mixture to be neutral by deionized water, freezing and drying the mixture, and grinding the mixture to obtain the hydrothermal carbon.

2)Fe₃O₄Hydrothermal charcoal preparation, dispersing 10g of the prepared hydrothermal charcoal in 30mL of ethylene glycol, and then adding FeCl₃·6H₂Dissolving O, adding 5mL of anhydrous sodium acetate, stirring to fully mix, ultrasonically dispersing for 20min, transferring to a reaction kettle, sealing and reacting at 250 ℃ for 2h at 200-₃O₄Hydrothermal charcoal, washing, freeze drying, grinding to obtain Fe₃O₄Hydrothermal charcoal, Fe₃O₄Is 25 percent.

3) Preparing a hydrothermal carbon-based urea fertilizer: weighing 1g r-polyglutamic acid, dissolving to 1% (V/V) glacial acetic acid water solution to obtain adhesive, wherein the mass concentration of r-polyglutamic acid solution is 0.1%, pulverizing urea by a pulverizer, sieving with a 50-100 mesh sieve, weighing urea, placing in a granulator, starting the granulator, setting the rotation speed at 40r/min, spraying binder during rotation, and slowly spraying Fe₃O₄Hydrothermal charcoal, Fe₃O₄The mass ratio of the hydrothermal carbon to the urea is 0.2:1, the granules are taken out after being formed, dried to constant weight at 40 ℃, and cooled to obtain the product.

Example 2

1) preparing the hydrothermal carbon, taking the excrement residue at the bottom of the first tank of the three-grid septic tank, naturally drying, crushing, sieving by a 50-100 mesh sieve, and then adding into a hydrothermal reaction kettle, wherein 18g of human excrement residue is added into every 100mL of water. Setting the heating rate at 10 ℃/min, carrying out hydrothermal reaction, respectively standing at 140 ℃, 180 ℃ and 220 ℃ for 30min, pouring out the supernatant after the reaction is finished, washing with deionized water to be neutral, freeze-drying, and grinding to obtain the hydrothermal carbon.

2)Fe₃O₄Hydrothermal charcoal preparation, dispersing 10g of the prepared hydrothermal charcoal in 30mL of ethylene glycol, and then adding FeCl₃·6H₂Dissolving O, adding 5mL of anhydrous sodium acetate, stirring to fully mix, ultrasonically dispersing for 20min, transferring to a reaction kettle, sealing and reacting at 250 ℃ for 2h at 200-₃O₄Hydrothermal charcoal, washing, freeze drying, grinding to obtain Fe₃O₄Hydrothermal charcoal, Fe₃O₄Is 15 percent.

3) Preparing a hydrothermal carbon-based urea fertilizer: weighing 1g r-polyglutamic acid, dissolving to 1% (V/V) glacial acetic acid water solution to obtain adhesive, wherein the mass concentration of r-polyglutamic acid solution is 0.2%, pulverizing urea by a pulverizer, sieving with a 50-100 mesh sieve, weighing urea, placing in a granulator, starting the granulator, setting the rotation speed at 40r/min, spraying binder during rotation, and slowly spraying Fe₃O₄Hydrothermal charcoal, Fe₃O₄The mass ratio of the hydrothermal carbon to the urea is 0.2:1, the granules are taken out after being formed, dried to constant weight at 40 ℃, and cooled to obtain the product.

Example 3

1) preparing the hydrothermal carbon, taking the excrement residue at the bottom of the first tank of the three-grid septic tank, naturally drying, crushing, sieving by a 50-100 mesh sieve, and then adding into a hydrothermal reaction kettle, wherein 20g of human excrement residue is added into every 100mL of water. Setting the heating rate at 12 ℃/min, carrying out hydrothermal reaction, respectively standing at 140 ℃, 180 ℃ and 220 ℃ for 35min, pouring out supernatant after the reaction is finished, washing with deionized water to be neutral, freeze-drying, and grinding to obtain the hydrothermal carbon.

2)Fe₃O₄Hydrothermal charcoal preparation, dispersing 10g of the prepared hydrothermal charcoal in 30mL of ethylene glycol, and then adding FeCl₃·6H₂Dissolving O, adding 5mL of anhydrous sodium acetate, stirring to fully mix, ultrasonically dispersing for 20min, transferring to a reaction kettle, sealing and reacting at 250 ℃ for 2h at 200-₃O₄Hydrothermal charcoal, washing, freeze drying, grinding to obtain Fe₃O₄Hydrothermal charcoal, Fe₃O₄Is 10 percent.

3) Preparing a hydrothermal carbon-based urea fertilizer: weighing 1g r-polyglutamic acid, dissolving to 1% (V/V) glacial acetic acid water solution to obtain adhesive, wherein the mass concentration of r-polyglutamic acid solution is 0.3%, pulverizing urea by a pulverizer, sieving with a 50-100 mesh sieve, weighing urea, placing in a granulator, starting the granulator, setting the rotation speed at 40r/min, spraying binder during rotation, and slowly spraying Fe₃O₄Hydrothermal charcoal, Fe₃O₄The mass ratio of the hydrothermal carbon to the urea is 0.3:1, the granules are taken out after being formed, dried to constant weight at 40 ℃, and cooled to obtain the product.

And the physicochemical property of the slow release fertilizer is detected by referring to the slow release characteristic detection standard (GB/T23348-2009).

(1) Compressive strength and wear resistance

Compressive strength: and randomly taking out 20 prepared hydrothermal carbon-based urea fertilizers, measuring the pressure resistance value of each fertilizer by using a texture analyzer, repeating for 5 times, and calculating the average value and the standard deviation of the fertilizers.

Wear resistance: and (4) measuring the wear resistance of the carbon-based urea fertilizer through the balance weight ratio. Weighing 3.00g to 50mL of prepared carbon-based urea fertilizer in a conical flask, mixing 8 steel beads into the fertilizer, sealing the opening of the conical flask, transferring the conical flask into a vibration incubator, oscillating the conical flask for 30min at a speed of 300r/min, taking out the conical flask, passing through a 0.4mm filter screen, weighing the mass of the residual fertilizer particles, calculating the residual weight ratio according to the ratio of the mass of the residual particles to the initial mass of the particles, and determining the wear resistance of the carbon-based fertilizer.

Remarking: in the table above, the hydrothermal carbon-based fertilizer is prepared from hydrothermal carbon according to the step 3). The modified hydrothermal carbon-based fertilizer prepared in example 2 was used in the modified hydrothermal carbon-based fertilizer of the present invention (the modified hydrothermal carbon-based fertilizer prepared in example 2 was also used in the following tests, and the test data of examples 1 and 3 were similar to those of example 2 and are not repeated here)

From the above table, it can be seen that the hydrothermal carbon has a relatively abundant pore structure, so that the adhesion during the coating process is insufficient, the average compressive capacity of the hydrothermal carbon-based urea fertilizer is 36.6N and is higher than 12N (critical value for measuring relatively high hardness), and the residual weight ratio homogeneity is higher than 97%. Compared with the hydrothermal carbon-based fertilizer, the compression resistance and the residual weight ratio of the modified hydrothermal carbon-based fertilizer are further improved, and the modified hydrothermal carbon-based fertilizer is convenient for the processes of collection, storage and transportation.

(2) Water absorption rate and water resistance

Generally, the lower the water absorption rate of the carbon-based fertilizer, the better the slow release effect. Testing the water absorbability of different carbon-based fertilizers according to a method of the national standard (GB/T23348-2009) of the slow-release fertilizer, and calculating the water absorption multiplying power of the water-absorbing carbon-based fertilizer in the process of achieving water absorption balance. The specific method comprises the following steps: taking 5.0g of fertilizer, filling the fertilizer into a nylon gauze bag with the aperture of 0.1-0.15mm, sealing, transferring the bag into a 250mL beaker, adding 150mL of deionized water, covering and sealing, and transferring the bag into a constant-temperature biochemical incubator at 25 ℃.

Carbon-based urea fertilizer slow-release water absorption rate

Time of Water absorption (h)	Urea	Water-heating carbon-based fertilizer	The invention relates to a modified water-heating carbon-based fertilizer
				6	2.15±0.08	1.31±0.04	1.63±0.02
12	2.61±0.03	1.53±0.06	1.87±0.04
				18	3.24±0.02	1.74±0.01	2.01±0.05
24	3.52±0.05	1.89±0.05	2.11±0.03
				30	3.54±0.05	1.92±0.03	2.14±0.04
36	3.55±0.07	1.94±0.02	2.14±0.01

From the above table, it can be seen that the water absorption rate of the hydrothermal carbon-based coated urea fertilizer is significantly reduced compared with urea, mainly because the hydrothermal carbon has a rich pore structure and a surface functional group structure, resulting in a stronger adsorption performance of the hydrothermal carbon. Meanwhile, the super-strong water absorbability of the r-polyglutamic acid has certain contribution to the water absorption rate of the slow release fertilizer. The water absorption rate of the modified hydrothermal carbon-based coated slow-release fertilizer is slightly improved (P is less than 0.05) because of Fe₃O₄The introduction of the carbon-based fertilizer increases the particle size of the carbon-based fertilizer and reduces the integral specific surface area and porosity.

Water resistance refers to the ability of a material to resist water damage. The longer the particles remain in the water, the greater the water resistance. 5.0g of fertilizer was weighed into a 250mL beaker, 150mL of deionized water was added, and the resulting mixture was placed in a constant temperature biochemical incubator at 25 ℃ to closely observe the dissolution of the granules. The result shows that urea is completely dissolved in deionized water within 2h, the hydrothermal carbon-based urea fertilizer is gradually flocculent on the surface of the particle from the 8 th day, and the dissolution is basically completed when the particle reaches 12 th day. Fe₃O₄The modified hydrothermal carbon-based urea fertilizer starts to dissolve at 13d until 20d is substantially completely dissolved. The water resistance of the modified hydrothermal carbon-based urea fertilizer is enhanced mainly in that r-polyglutamic acid forms a smooth coating on the surface of particles, so that the particles are not easily soaked by water molecules, and the retention time in water is long. Fe₃O₄The water resistance of the modified hydrothermal carbon-based urea fertilizer is further increased by Fe in the granules²⁺The increase of the concentration further increases the water resistance of the surface coating.

(3) Nitrogen release characteristics of carbon-based fertilizer

And performing an earth pillar intermittent leaching experiment by referring to a slow release characteristic detection standard GB/T23349-2009 to evaluate the slow release characteristic of the slow release fertilizer. The inner diameter of the leaching column is 4cm, the column height is 25cm, the tube bottom is tightly banded and sealed by two layers of non-woven fabrics, and the leaching column is provided with a constant flow pump. Before rinsing begins, the quartz sand is washed by distilled water until the rinsing liquid is clear, the quartz sand passes through a 40-mesh screen after being dried, and then a mixed layer (6cm) → quartz sand (5cm) → two layers of non-woven fabrics from top to bottom according to the quartz sand (5cm) → carbon-based fertilizer (5.0g) + soil (20 g), and the content of Cr (VI) being 5.24 mg/kg. Simulating natural precipitation and precipitation every 24 hours, uniformly spraying 100mL of distilled water by using a constant flow pump, collecting leacheate by using a 250mL beaker, and measuring the concentration of urea in the leacheate by adopting a dimethylaminobenzaldehyde color development spectrophotometry method. And (3) when the leaching is finished, determining the content of Cr (VI) in the soil and the leacheate by using an alkali solution extraction-flame atomic absorption spectrophotometry (HJ 1082-2019).

As can be seen from fig. 4, the modified hydrothermal carbon-based urea fertilizer has the best slow release performance, the hydrothermal carbon-based urea fertilizer has the next highest slow release rate, and the initial nutrient dissolution rates of the modified hydrothermal carbon-based urea fertilizer, the hydrothermal carbon-based urea fertilizer and the urea are 5.7%, 7.5% and 21.2%, respectively. Complete release of the contained nitrogen at 45d, 35d and 20d, respectively. The dissolution rate of the initial nutrients shows that the carbon-based fertilizer is complete in coating and contains rich pore structures, so that the rapid release of the nutrients is inhibited.

Capability of carbon-based urea fertilizer in removing Cr (VI)

Type of fertiliser	Content (mg/kg) of Cr (VI) in soil	Cr (VI) concentration (mg/L) in leacheate
			Urea	4.65	0.025
Water-heating carbon-based fertilizer	3.26	0.017
			The invention relates to a modified water-heating carbon-based fertilizer	2.57	0.011

As can be seen from the table, the addition of the hydrothermal carbon and the modified hydrothermal carbon based urea fertilizer reduces the content of Cr (VI) in the whole reaction system. This is because the hydrothermal carbon surface contains abundant oxygen-containing functional groups, which can increase the coulomb attraction with Cr (VI) and simultaneously perform redox reaction, thereby realizing the removal of Cr (VI). Fe²⁺/Fe³⁺As the electronic shuttle, the capability of removing Cr (VI) is further enhanced. The r-polyglutamic acid is used as a good flocculating agent and also contributes to the removal of Cr (VI).

(4) Recoverability and stability of modified hydrothermal carbon-based urea fertilizer

Based on the recycling concept, the recovery performance of the modified hydrothermal carbon-based material is explored. As shown in the figure, the saturation magnetization of the hydrothermal carbon-based urea fertilizer is about 0emu/g, while the magnetization of the modified hydrothermal carbon-based urea fertilizer can reach 21.26emu/g, so that the modified hydrothermal carbon-based urea fertilizer has strong magnetic recovery performance and is easy to recover from soil. After being washed and dried, the urea fertilizer is repeatedly used for 6 times with the urea fertilizer for preparing the modified hydrothermal carbon-based urea fertilizer, and the complete dissolution time of nutrients can be maintained to be more than 35 days.

(5) Experiment of potted lettuce

Lettuce is taken as a research object, the actual effect of the carbon-based urea fertilizer is measured through the crop yield and the nitrogen fertilizer utilization rate, and the experimental scheme is as follows:

kind of fertilizer	Fertilizer quality (g/basin)	Potassium chloride (g/basin)	Perphosphoric acid quality (g/basin)
				Urea	0.5	1.34	0.33
Water-heating carbon-based fertilizer	2.0	1.34	0.33
				Modified water-heating carbon-based fertilizer	2.0	1.34	0.33

After the fertilizer and 2.0kg of soil are fully mixed, 2 lettuce plants are planted in each pot for 3 groups of parallel experiments, and the yield of the lettuce is observed after 45 days, as shown in the table

Kind of fertilizer	Yield g/granule	Increase in yield/%)
			Urea	91.04±0.32	-
Water-heating carbon-based fertilizer	114.25±0.27	20.31
			The invention relates to a modified water-heating carbon-based fertilizer	125.68±0.14	27.56

Compared with the traditional urea, the yield of the lettuce under the condition of the hydrothermal carbon-based fertilizer is increased by 20.31 percent, and the yield of the lettuce under the condition of the modified hydrothermal carbon-based fertilizer is increased by 27.56 percent.

The present invention is not limited to the above-described embodiments, and those skilled in the art will understand that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

Translated fromChinese

1.一种人粪水热炭基包膜尿素肥的制备方法，其特征在于，按照如下步骤制备：1. a preparation method of human excrement hydrothermal carbon-based coated urea fertilizer, is characterized in that, prepares according to the following steps:

1)制备水热炭，取三格化粪池第一池底部粪渣，自然风干后粉碎过筛，然后投加至水热反应釜中，设置升温速率为8-12℃/min，进行水热反应，反应完后倒掉上清液，用去离子水洗涤至中性，冷冻干燥，研磨得到水热炭；1) To prepare hydrothermal charcoal, take the manure residue at the bottom of the first tank of the three-grid septic tank, pulverize and sieve it after natural air-drying, then add it to the hydrothermal reaction kettle, set the heating rate to be 8-12 ℃/min, and carry out the water treatment. Thermal reaction, pour off the supernatant after the reaction, wash with deionized water until neutral, freeze-dry, and grind to obtain hydrothermal charcoal;

2)Fe₃O₄/水热炭制备，将制备的水热炭分散于乙二醇中，然后加入FeCl₃·6H₂O溶解，再加入无水乙酸钠，搅拌使其充分混合，超声分散后转移至反应釜中，密封反应，反应完后取出，冷却，磁分离出Fe₃O₄/水热炭，洗涤，冷冻干燥，研磨得到Fe₃O₄/水热炭，Fe₃O₄的质量分数为10％-25％；2) Preparation of Fe₃ O₄ /hydrothermal carbon, disperse the prepared hydrothermal carbon in ethylene glycol, then add FeCl₃ ·6H₂ O to dissolve, then add anhydrous sodium acetate, stir to make it fully mixed, and ultrasonically disperse Then transfer to the reaction kettle, seal the reaction, take out after the reaction, cool, magnetically separate out Fe₃ O₄ /hydrothermal charcoal, wash, freeze-dry, grind to obtain Fe₃ O₄ /hydrothermal charcoal, Fe₃ O₄ The quality fraction is 10%-25%;

3)水热炭基尿素肥制备：称取r-聚谷氨酸溶解至冰乙酸的水溶液中得到粘接剂，将尿素经粉碎机粉碎后过筛，随后，称取尿素置于造粒机中，启动造粒机，转动过程中喷洒粘结剂，同时缓慢撒入Fe₃O₄/水热炭，待颗粒成型后取出，烘干至恒重，冷却得到产品。3) Preparation of hydrothermal carbon-based urea fertilizer: take r-polyglutamic acid and dissolve it in an aqueous solution of glacial acetic acid to obtain a binder, sieve the urea after being pulverized by a pulverizer, and then weigh the urea and place it in a granulator In the process, start the granulator, spray the binder during the rotation, and at the same time slowly sprinkle Fe₃ O₄ /hydrothermal charcoal, after the granules are formed, take out, dry to constant weight, and cool to obtain the product.

2.根据权利要求1所述人粪水热炭基包膜尿素肥的制备方法，其特征在于：步骤1)中，在反应时，分别在140℃、180℃和220℃停留反应30-40min。2. the preparation method of human excrement hydrothermal carbon-based coated urea fertilizer according to claim 1, is characterized in that: in step 1), during reaction, stay and react 30-40min at 140 ℃, 180 ℃ and 220 ℃ respectively .

3.根据权利要求2或3所述人粪水热炭基包膜尿素肥的制备方法，其特征在于：步骤1)中，在水热反应釜中加入的人粪粪渣与水的比例为每100mL水加入人粪粪渣15-20g。3. according to the preparation method of the described human excrement hydrothermal carbon-based coated urea fertilizer of claim 2 or 3, it is characterized in that: in step 1), in the hydrothermal reactor, the ratio of the human excrement dung residue and water that adds is Add 15-20g of human feces to every 100mL of water.

4.根据权利要求3所述人粪水热炭基包膜尿素肥的制备方法，其特征在于：步骤2)中，反应温度为200-250℃。4. the preparation method of human excrement hydrothermal carbon-based coated urea fertilizer according to claim 3, is characterized in that: in step 2), reaction temperature is 200-250 ℃.

5.根据权利要求4所述人粪水热炭基包膜尿素肥的制备方法，其特征在于：r-聚谷氨酸溶液的质量浓度为0.1-0.3％。5. the preparation method of the human excrement hydrothermal carbon-based coated urea fertilizer according to claim 4, is characterized in that: the mass concentration of r-polyglutamic acid solution is 0.1-0.3%.

6.根据权利要求5所述人粪水热炭基包膜尿素肥的制备方法，其特征在于：冰乙酸水溶液中冰乙酸的体积浓度为1％。6. the preparation method of human excrement hydrothermal carbon-based coated urea fertilizer according to claim 5 is characterized in that: the volume concentration of glacial acetic acid in the glacial acetic acid aqueous solution is 1%.

7.根据权利要求6所述人粪水热炭基包膜尿素肥的制备方法，其特征在于：Fe₃O₄/水热炭与尿素的质量比为0.2-0.3:1。7. the preparation method of human excrement hydrothermal carbon-based coated urea fertilizer according to claim 6, is characterized in that: the mass ratio of Fe₃ O₄ / hydrothermal carbon and urea is 0.2-0.3:1.

8.根据权利要求1所述人粪水热炭基包膜尿素肥的制备方法，其特征在于：粪渣及尿素粉碎后均过50-100目筛。8. the preparation method of human excrement hydrothermal carbon-based coated urea fertilizer according to claim 1, is characterized in that: all 50-100 mesh sieves are crossed after excrement residue and urea are pulverized.

9.一种权利要求1-8任一项所述人粪水热炭基包膜尿素肥的制备方法制备得到的人粪水热炭基包膜尿素肥。9. The human excrement hydrothermal carbon-based coated urea fertilizer prepared by the preparation method of any one of claims 1-8.