CN106673896A - Lotus leaf carbon based fertilizer and preparation method thereof - Google Patents

Abstract

The invention discloses a method for preparing lotus leaf charcoal-based fertilizer using discarded lotus leaves as raw materials. Fresh lotus leaves are hydrothermally carbonized under anoxic conditions to form lotus leaf biochar. The method requires relatively low energy consumption and cost. It is conducive to realizing the resource utilization of waste biomass. The lotus leaf biochar of the invention can be used as base fertilizer, can increase soil organic matter, nitrogen, phosphorus and potassium content, promote crop yield increase, and improve crop quality.

Description

A kind of lotus leaf charcoal-based fertilizer and preparation method thereof

technical field

The invention belongs to the technical field of biomass charcoal-based fertilizer preparation, and in particular relates to a lotus leaf charcoal-based fertilizer based on soil fertilization and a preparation method thereof.

Background technique

At present, in agricultural production, the amount of chemical fertilizer used per unit area in my country is 1.6 times the world average, and the total annual amount is as high as more than 100 million tons. In the past 10 years, the total amount of chemical fertilizers in my country has increased by more than 90%, while the total grain output has only increased by about 9%. The utilization rate of nitrogen, phosphorus and potassium fertilizers is low, which has caused economic losses and waste of resources, as well as ecological environment. Pollution and soil quality have seriously deteriorated. Therefore, scientific and rational use of fertilizers, improvement of soil physical and chemical properties, and improvement of soil fertility are crucial to the sustainable development of agriculture.

The main component of biochar-based fertilizer is biochar, which has a large specific surface area and more pores, and is rich in organic carbon and mineral nutrients. It is applied to the soil as a soil improver and fertilizer to increase soil organic matter and nutrients. Improve the activity of soil microorganisms, increase the yield of agricultural products, and slow down the greenhouse effect. In addition, the special material composition and structure of biochar make it capable of adsorbing inorganic and organic pollutants, which is of great significance for improving the environment of the production area and improving the quality and safety of agricultural products. Biochar application can change soil physical and chemical properties, increase soil water and fertilizer retention performance, and increase soil fertility. The light porous structure of biochar can directly reduce soil bulk density, increase total porosity, improve soil fertility and increase the stability and content of soil organic matter. Compared with straw, green manure, compost and other fertilization measures, the stability of biochar Stronger and lasts longer in the soil. The charge generated by biochar and the huge specific surface area have a strong adsorption effect on the nutrients needed by soil and plants, reduce nutrient loss and increase soil fertility. At the same time, biochar itself contains certain nutrients such as C, N, P, and K. Under the interaction with the soil ecological environment, some nutrient elements are slowly released for crops to absorb and utilize, increasing soil fertility. Due to these good physical, chemical and biological properties of biochar, the rational development and research of carbon-based fertilizers using waste biomass as raw materials is one of the important ways for the development of rural economy and ecological cycle agriculture.

In the existing biochar preparation, the pyrolytic carbonization method has disadvantages such as high temperature and excessive energy consumption, while hydrothermal carbonization refers to the charcoal with extremely rich carbon content obtained by high-temperature pyrolysis of biomass in a low-oxygen environment. Moreover, hydrothermal carbonization using waste lotus leaves as raw materials has not been reported in the prior art, and hydrothermal carbonization is more suitable for the treatment of waste lotus leaves. Therefore, a method for treating waste lotus leaves is urgently needed in this field.

Contents of the invention

One of the technical problems to be solved in the present invention is to provide a method for hydrothermal carbonization to prepare waste lotus leaf biochar-based special fertilizer. In order to achieve the purpose of the present invention, the technical scheme adopted is as follows:

A preparation method of lotus leaf charcoal-based fertilizer, characterized in that: comprising the following steps,

A. Fresh lotus leaves are cleaned to obtain biomass materials;

B. Put the biomass material into a sealed hydrothermal carbonization reactor, add a certain proportion of water, and carry out carbonization under airtight anaerobic conditions; the mass ratio of biomass material to water by dry weight is 1:5~1 : 20; the stirring speed is 100～800r·min ^-1 ; the temperature is 180～260℃; the reaction pressure is 1.0～4.0MPa, and the reaction time is 2～8h;

C. After the reaction is completed, cool to room temperature, wash with distilled water, and dry to obtain lotus leaf biochar.

Further, in step B, the mass ratio of biomass material to water is 1:12-15 in terms of dry weight.

In step B, the hydrothermal carbonization reaction temperature is preferably 200-220° C.; the reaction pressure is preferably 2-3 MPa.

In a preferred embodiment of the present invention, under the condition of isolated air, the stirring speed is 200r·min ^-1 ; the temperature is 200°C; the time is 6h; the specific surface area is 32.0034m ² /g, and the organic carbon content is 510g/kg, The total nitrogen content is 9570mg/kg, the total phosphorus is 2100mg/kg, and the total potassium content is 3780mg/kg.

Another object of the present invention is to provide a lotus leaf charcoal-based fertilizer, characterized in that: the specific surface area of the lotus leaf charcoal-based fertilizer is ^{1.9642-32.0034m2} /g, the organic carbon content is 402-510g/kg, and the total nitrogen The content is 9100-10500mg/kg, the total phosphorus content is 258-2100mg/kg, and the total potassium content is 3210-4690mg/kg; it is prepared by the following steps:

A. Fresh lotus leaves are cleaned to obtain biomass materials;

B. Put the biomass material into a sealed hydrothermal carbonization reactor, add a certain proportion of water, and carry out carbonization under airtight anaerobic conditions; the mass ratio of biomass material to water by dry weight is 1:5~1 : 20; the stirring speed is 100～800r·min ^-1 ; the temperature is 180～260℃; the reaction pressure is 1.0～4.0MPa, and the reaction time is 2～8h;

C. After the reaction is completed, cool to room temperature, wash with distilled water, and dry to obtain lotus leaf biochar.

In step B, the mass ratio of biomass material to water is 1:12-15 in terms of dry weight.

In step B, the hydrothermal carbonization reaction temperature is preferably 200-220° C.; the reaction pressure is preferably 2-3 MPa.

The lotus leaf charcoal-based fertilizer of the invention can be applied to soil fertilization, can increase soil organic carbon content, nitrogen, phosphorus and potassium content, promote crop yield increase, and increase lotus root starch and protein content.

The present invention has the following advantages:

1. The lotus leaf biochar-based fertilizer for soil fertilization and improvement prepared by hydrothermal carbonization technology in the present invention has milder reaction conditions and lower energy consumption than pyrolysis carbonization.

2. The process of preparing soil improvement biochar by hydrothermal carbonization is simpler and easier to operate, which is more conducive to the promotion and application of waste biomass resource utilization.

3. Using waste lotus leaves as raw materials is conducive to the recycling of resources, realizing agricultural energy saving and emission reduction, and significantly improving the ecological environment.

4. The hydrothermal charcoal made from waste lotus leaves is rich in nutrients needed for the growth of lotus root and has a high specific surface area. As a special fertilizer for lotus root, it is beneficial to promote the growth of lotus root and increase production and income.

5. The hydrothermal carbon-based fertilizer using waste lotus leaves as raw materials has a more obvious effect on increasing fertilizer and yield than returning it directly to the field, and it also reduces the risk of soil pathogens and crop diseases.

Description of drawings

Fig. 1 is the scanning electron micrograph of the microscopic morphology of the lotus leaf biochar-based fertilizer of the present invention.

Fig. 2 is a schematic diagram of the physical and chemical properties of the soil during the harvest period in the simulation test of the lotus leaf carbon-based fertilizer obtained in Examples 1 to 4 in the research base.

detailed description

Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

The present invention will be further described in detail below in conjunction with examples.

Example 1

The preparation method of special fertilizer for lotus leaf biochar based on soil fertilization and improvement comprises the following steps:

1. Clean the fresh lotus leaves, cut them into <2cm ² size, and dry them in the sun to obtain dried raw materials;

2. Mix the raw material and water at a ratio of 1:12, put it into a sealed hydrothermal carbonization reaction kettle, and mix well so that the water fully immerses the biomass raw material. The reaction conditions of the reactor were as follows: the stirring speed was 200r·min ^-1 , the temperature was raised to 200°C at a constant temperature of 10°C/min for 6h. After the reaction, cool to room temperature, wash with distilled water, and dry at 80°C; grind and pass through a 10-mesh sieve to obtain a lotus leaf biochar-based fertilizer. The microscopic morphology is shown in Figure 1.

The yield of the lotus leaf charcoal-based fertilizer obtained in this example is 65.83%, the specific surface area is 32.0034m ² /g, the organic carbon content is 510g/kg, the total nitrogen content is 9570mg/kg, the total phosphorus is 2100mg/kg, and the total potassium content It is 3780mg/kg.

Wherein, lotus leaf charcoal-based fertilizer yield=(solid phase product dry matter quality/raw material dry matter quality)×100%

Example 2

The preparation method of special fertilizer for lotus leaf biochar based on soil fertilization and improvement comprises the following steps:

1. Clean the fresh lotus leaves and cut them into a size of <2cm ² to obtain biomass raw materials;

2. Mix the biomass raw material with water at a mass ratio of 1:12 by dry weight, put it into a sealed hydrothermal carbonization reaction kettle, and mix well so that the water fully immerses the biomass raw material. The reaction conditions of the reactor were as follows: the stirring speed was 300r·min ^-1 , the temperature was raised to 240°C at a constant temperature of 10°C/min for 6h. After the reaction is finished, cool to room temperature, wash with distilled water, and dry at 80°C; grind and pass through a 10-mesh sieve to obtain a lotus leaf biochar-based fertilizer.

The yield of the lotus leaf carbon-based fertilizer obtained in this example is 59.56%, the specific surface area is ^11.4321m2 /g, the organic carbon content is 484g/kg, the total nitrogen content is 9420mg/kg, the total phosphorus is 1420mg/kg, and the total potassium content It is 3590mg/kg.

Example 3

The preparation method of special fertilizer for lotus leaf biochar based on soil fertilization and improvement comprises the following steps:

1. Clean the fresh lotus leaves, cut them into <2cm ² size, and dry them in the sun to obtain dried raw materials;

2. Mix the raw material with water at a ratio of 1:5, put it into a sealed hydrothermal carbonization reaction kettle, and mix well so that the water fully immerses the biomass raw material. The reaction conditions of the reactor were as follows: the stirring speed was 200r·min ^-1 , the temperature was raised to 200°C at a constant temperature of 10°C/min for 6h. After the reaction is finished, cool to room temperature, wash with distilled water, and dry at 80°C; grind and pass through a 10-mesh sieve to obtain a lotus leaf biochar-based fertilizer.

The yield of the lotus leaf carbon-based fertilizer obtained in this example is 68.67%, the specific surface area is ^6.528m2 /g, the organic carbon content is 499g/kg, the total nitrogen content is 9830mg/kg, the total phosphorus is 1940mg/kg, and the total potassium content It is 3920mg/kg.

Example 4

The preparation method of special fertilizer for lotus leaf biochar based on soil fertilization and improvement comprises the following steps:

1. Clean the fresh lotus leaves and cut them into a size of <2cm ² to obtain biomass raw materials;

2. Mix the biomass raw material with water at a mass ratio of 1:20 by dry weight, put it into a sealed hydrothermal carbonization reaction kettle, and mix well so that the water fully immerses the biomass raw material. The reaction conditions of the reactor were as follows: the stirring speed was 200r·min ^-1 , the temperature was raised to 200°C at a constant temperature of 10°C/min for 6h. After the reaction is finished, cool to room temperature, wash with distilled water, and dry at 80°C; grind and pass through a 10-mesh sieve to obtain a lotus leaf biochar-based fertilizer.

The yield of the lotus leaf charcoal-based fertilizer obtained in this example is 64.15%, the specific surface area is ^15.7682m2 /g, the organic carbon content is 512g/kg, the total nitrogen content is 9458mg/kg, the total phosphorus is 1880mg/kg, and the total potassium content It is 3690mg/kg.

Example 5

The lotus leaf charcoal-based fertilizer prepared in Examples 1 to 4 was subjected to a simulation test at the research base.

The test simulates the potted plant test as follows: test tank: 200L ceramic tank; test soil: Anhui Tongling soil; 60kg air-dried soil per tank; lotus root variety: Elian No. 6. The properties of the tested soil are: pH 6.25, cation exchange capacity 11.05cmol(+)/kg, organic carbon content 13.1g/kg; total nitrogen content 850mg/kg; total phosphorus content 298mg/kg; total potassium The content is 1.58*10 ⁴ mg/kg; the content of alkaline hydrolysis nitrogen is 65.8 mg/kg; the content of available phosphorus is 6.5 mg/kg, and the content of available potassium is 65.7 mg/kg. Apply 20g of compound fertilizer (N: P ₂ O ₅ : K ₂ O ≥ 60%, N: P ₂ O ₅ : K ₂ O=20: 20:20). The lotus leaf charcoal-based fertilizer prepared in Examples 1 to 4 was evenly spread and plowed into the soil, and the dosage was 300g/cylinder. See Figure 2 and Table 1 for the soil and lotus root properties during the harvest period.

Table 1 Yield and quality of lotus root during harvest period

After applying the lotus leaf charcoal-based fertilizer, the soil pH, cation exchange capacity, organic carbon content, total nitrogen content, total phosphorus, and total potassium content all increased, and the content of available phosphorus and available potassium increased significantly. At the same time, the yield of lotus root and The content of starch and protein indicated that the lotus leaf charcoal-based fertilizer has the properties of improving soil properties, maintaining and increasing fertilizer, and improving crop yield and quality.

The above descriptions are preferred embodiments of the present invention, and improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims (6)

1. a preparation method of lotus leaf charcoal-based fertilizer, is characterized in that: comprise the following steps, A. Fresh lotus leaves are cleaned to obtain biomass materials; B. Put the biomass material into a sealed hydrothermal carbonization reactor, add a certain proportion of water, and carry out carbonization under airtight anaerobic conditions; the mass ratio of biomass material to water by dry weight is 1:5~1 : 20; the stirring speed is 100～800r·min ^-1 ; the temperature is 180～260℃; the reaction pressure is 1.0～4.0MPa, and the reaction time is 2～8h; C. After the reaction is completed, cool to room temperature, wash with distilled water, and dry to obtain lotus leaf biochar. 2. The preparation method of lotus leaf charcoal-based fertilizer according to claim 1, characterized in that the mass ratio of biomass material to water in step B is 1:12-15. 3. The preparation method of lotus leaf charcoal-based fertilizer according to claim 1, characterized in that: in step B, the hydrothermal carbonization reaction temperature is 200-220° C.; the reaction pressure is 2-3 MPa. 4. A lotus leaf charcoal-based fertilizer, characterized in that: the specific surface area of the lotus leaf charcoal-based fertilizer is between ^{1.9642-32.0034m2} /g, the organic carbon content is 402-510g/kg, and the total nitrogen content is 9100- 10500mg/kg, total phosphorus 258-2100mg/kg, total potassium 3210-4690mg/kg; prepared by the following steps: A. Fresh lotus leaves are cleaned to obtain biomass materials; B. Put the biomass material into a sealed hydrothermal carbonization reactor, add a certain proportion of water, and carry out carbonization under airtight anaerobic conditions; the mass ratio of biomass material to water is 1:5-1:20; stir The rotation speed is 100~800r·min ^-1 ; the temperature is 180~260℃; the reaction pressure is 1.0~4.0MPa, and the reaction time is 2~8h; C. After the reaction is completed, cool to room temperature, wash with distilled water, and dry to obtain lotus leaf biochar. 5. The lotus leaf charcoal-based fertilizer according to claim 4, characterized in that the mass ratio of biomass material to water in step B is 1:12-15. 6. The lotus leaf charcoal-based fertilizer according to claim 5, characterized in that, in step B, the hydrothermal carbonization reaction temperature is 200-220° C.; the reaction pressure is 2-3 MPa.