Carbon nano-particles capable of effectively improving soil properties of saline-alkali soil and application of carbon nano-particles

Abstract

The invention belongs to the technical field of soil improvement, and particularly relates to carbon nano-particles capable of effectively improving soil properties of saline-alkali soil and application of the carbon nano-particles. The particle size of the carbon nano-particles is 2-6 nm, the carbon nano-particles are composed of three elements of C, H and O, and the surfaces of the carbon nano-particles are provided with oxygen-containing functional groups; the carbon nanoparticles can improve the composition of soil microorganisms, increase the activity of bacillus subtilis, specifically promote the absorption of total nitrogen and hydrolytic nitrogen in soil, improve the granular structure of soil, and achieve the purposes of improving saline-alkali soil and promoting plant growth. According to the preparation module, a graphite rod is placed in electrolyte, voltage is applied, electrolysis is carried out for several days until the positive electrode carbon rod is completely etched, black electrolyte is filtered once with qualitative filter paper, large-particle precipitates are removed, and the soil conditioner can be obtained. The method has the advantage that a large amount of carbon nanoparticles with uniform particle sizes can be simply and quickly prepared for improving saline-alkali soil.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil improvement, and in particular relates to carbon nanoparticles that can effectively improve the soil properties of saline-alkali land and applications thereof. Background Art

[0002] Saline-alkali land refers to a type of land with excessively high salt or alkaline content in the soil, resulting in poor soil structure, poor permeability and low fertility. The high salinity and alkalinity of this type of soil will affect the normal growth of crops, damage plant roots, and reduce the ability to absorb water and nutrients, thus seriously restricting agricultural productivity.

[0003] The formation of saline-alkali land can be caused by a variety of factors, including salt accumulation under natural conditions, improper water resource management, over-irrigation and poor drainage. In many arid and semi-arid areas, salt rises to the soil surface with groundwater, and as water evaporates, salt accumulates on the surface, forming saline-alkali land. In addition, in modern agricultural production, in order to increase production, farmers often apply a large amount of nitrogen fertilizer. However, excessive nitrogen fertilizer accumulates in the soil in the form of nitrates and ammonium salts. Especially in the case of poor drainage conditions or improper irrigation management, the accumulation of these nitrogen will aggravate the problem of soil salinization.

[0004] Traditional saline-alkali land improvement methods, including irrigation and leaching, and increasing organic matter, can alleviate the salinity problem to a certain extent, but they are time-consuming, costly, and have the problem of polluting water bodies. In areas with scarce water resources, traditional leaching methods are difficult to implement. Efficient soil conditioners are of great significance to soil improvement.

[0005] There are many types of saline-alkali land improvers on the market, but there are still many problems in terms of use effect, environmental friendliness and applicability. Some improvers may cause secondary pollution to the environment, or their improvement effect is not lasting, so a more efficient, environmentally friendly and economical improver is needed to meet the needs of saline-alkali land management.

[0006] In response to the above problems, the research and development goal of new saline-alkali land soil conditioners is to develop an environmentally friendly conditioner that can quickly reduce soil salinity and alkalinity, enhance soil fertility, and be harmless to the environment through scientific formulas and processes. This type of conditioner should be easy to use, effective, and long-term, and can be applied to different types of saline-alkali land, and help achieve sustainable agricultural development. Summary of the invention

[0007] In view of the above problems, the purpose of the present invention is to develop an environmentally friendly improver that can quickly reduce soil salinity and alkalinity, enhance soil fertility, and improve soil properties to promote the sustainable development of agricultural production.

[0008] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0009] In order to solve the above-mentioned technical problems, this application provides the following technical solutions:

[0010] The present invention provides a carbon nanoparticle that can effectively improve the soil properties of saline-alkali land. The carbon nanoparticle is obtained by filtering a positive electrode and a negative electrode after passing electricity in an electrolyte for 20-40 days; the positive electrode is composed of a plurality of graphite rods with a spacing of 5-8 cm between each other; the negative electrode is composed of a platinum wire (i.e., a platinum wire electrode); the electrolyte is ultrapure water with a conductivity greater than 18.2 MΩ·cm -1 ; The voltage of the positive and negative electrodes is 10-100V.

[0011] Preferably, the electrolyte also includes one or more of nitrogen, phosphorus and potassium.

[0012] Specifically, when water is used as the electrolyte, undoped carbon nanoparticles are prepared. In addition, the electrolyte contains nitrogen solvents, phosphorus solvents, and potassium solvents, and by adjusting the concentrations and proportions of these electrolytes, soil-improving carbon nanoparticles with composite effects of nitrogen supplementation, phosphorus supplementation, and potassium supplementation can be obtained for different soil types.

[0013] Preferably, the particle size of the carbon nanoparticles is 2-6 nm.

[0014] Preferably, the surface of the carbon nanoparticles has oxygen-containing functional groups.

[0015] Furthermore, the oxygen-containing functional group is selected from -OH, -COOH or COC.

[0016] Preferably, the pH value of the carbon nanoparticles in water is 4-5.

[0017] Preferably, the voltage at which the positive electrode and the negative electrode are powered is 10-100V.

[0018] Preferably, the filtering method is filtering using qualitative filter paper.

[0019] Specifically, the method for preparing the carbon nanoparticles comprises the following steps:

[0020] Step 1) Take some graphite rods and wash them with pure water. The conductivity of the pure water used for washing should not be less than 14MΩ·cm -1 ;

[0021] Step 2) placing the cleaned graphite rods in an electrolyte, and maintaining a distance of 5-8 cm between the two graphite rods; the number of graphite rods used can be increased according to the length of the preparation device.

[0022] Step 3) Connect a positive electrode in parallel to the graphite rod to form a loop with the platinum wire electrode at the bottom of the device, and continue electrolysis for several days until the electrolyte turns black and the graphite rod is completely etched;

[0023] Step 4) The obtained black electrolyte is filtered once with qualitative filter paper to remove the precipitated graphite oxide and graphite particles, thereby obtaining carbon nanoparticles that can effectively improve the soil properties of saline-alkali land.

[0024] The present invention also provides the use of the carbon nanoparticles in treating saline-alkali soil, comprising the following steps:

[0025] S1: dissolving carbon nanoparticles in water to obtain a carbon nanoparticle solution;

[0026] S2: evenly pouring the carbon nanoparticle solution into the plowed saline-alkali soil;

[0027] S3: After 20-28 hours, plants are planted on the saline-alkali soil described in step S2.

[0028] Preferably, the amount of carbon nanoparticles poured into the saline-alkali soil is 0.5 g / m2.

[0029] In summary, compared with other methods, the method for preparing carbon nanoparticles of the present invention has the advantages of being able to simply and quickly prepare carbon nanoparticles with high purity and uniform particle size, and being able to design carbon nanoparticles with different functions according to actual soil characteristics.

[0030] The technical solution of the present invention has the following advantages over the prior art:

[0031] Compared with other methods, the method for preparing carbon nanoparticles of the present invention has the advantage that different kinds of carbon nanoparticles with high purity and uniform particle size can be prepared simply and quickly. In addition, the carbon nanoparticles of the present invention have good biocompatibility, non-toxicity and biodegradability. In addition, the preparation device designed by the present invention has the characteristics of high output and fast speed compared with the traditional etching device, and is easier to mass produce. The most important thing is that this carbon nanoparticle can improve the soil properties of saline-alkali land and increase the yield performance of crops. Compared with traditional soil conditioners, it has the advantages of small dosage (0.33kg / mu), easy use (directly poured into the soil, no need to mix the soil), wide use scenarios (applicable to saline-alkali land, salinized soil of facility vegetable fields, low soil fertility soil, heavy metal contaminated soil, etc.), no secondary pollution risk, etc.

[0032] In the present invention, if the preparation liquid is replaced with a nitrogen compound solution, such as potassium nitrate (KNO3), a preparation having the dual functions of soil improvement and nitrogen fertilizer can be prepared. Therefore, the method has good scalability.

[0033] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The specific implementation of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the preparation method of the present invention;

[0035] Figure 2 This is a transmission electron microscope image of the carbon nanoparticles prepared by the present invention;

[0036] Figure 3 The particle size distribution diagram of the carbon nanoparticles prepared by the present invention;

[0037] Figure 4 The infrared spectrum of the carbon nanoparticles prepared by the present invention;

[0038] Figure 5 The X-ray photoelectron spectrum of the carbon nanoparticles prepared by the present invention;

[0039] Figure 6 The graphs showing the determination of total nitrogen and hydrolyzed nitrogen content in the soil after the saline-alkali soil was treated with the carbon nanoparticles prepared by the present invention for 60 days and 120 days;

[0040] Figure 7 The soil aggregate structure distribution diagram after the saline-alkali soil is treated with the carbon nanoparticles prepared by the present invention for 60 days and 120 days;

[0041] Figure 8 This is a comparison diagram of soil flora diversity after saline-alkali soil was treated with carbon nanoparticles prepared by the present invention for 120 days;

[0042] Fig. 9 This is a distribution diagram of the number of different bacterial communities in the soil after the saline-alkali soil was treated with the carbon nanoparticles prepared by the present invention for 120 days;

[0043] Fig.10 This is a distribution diagram of the number of soil fungal communities after saline-alkali soil has been treated with the carbon nanoparticles prepared by the present invention for 120 days;

[0044] Fig.11 This is a scanning electron microscope image of soil beneficial bacteria Bacillus subtilis after being treated with the carbon nanoparticles prepared by the present invention;

[0045] Fig.12 This is a comparison diagram of the growth status of the beneficial soil bacteria Bacillus subtilis after being treated with the carbon nanoparticles prepared by the present invention;

[0046] Fig.13A comparison diagram of the accumulation rate of active nitrogen in leaves of lettuce planted in saline-alkali soil treated with the carbon nanoparticles prepared by the present invention;

[0047] Fig.14 A phenotypic comparison diagram of lettuce grown in saline-alkali soil treated with the carbon nanoparticles prepared by the present invention. DETAILED DESCRIPTION

[0048] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0049] Example

[0050] A carbon nanoparticle that can effectively improve the soil properties of saline-alkali land, and a preparation device thereof Figure 1 As shown, the rectangular glass cylinder has a platinum wire electrode fixed in the center of the bottom, connected to the negative electrode. 4 / 5 of the water in the cylinder has a resistivity of 18.2MΩ·cm -1 Ultrapure water, insert 4 graphite rods above the negative electrode. The number of graphite rods connected to the negative electrode can be increased or decreased according to the size of the container. The distance between every two graphite rods is 8cm, and they are connected to the positive electrode.

[0051] This kind of carbon nanoparticles has the following characteristics:

[0052] See also Figure 2 As shown in Figure 3, transmission electron microscopy shows that the particle size of the carbon nanoparticles of the present invention is 2 to 6 nm.

[0053] See also Figure 4 , Figure 5 As shown, it can be known from the tests of infrared and X-ray photoelectron spectroscopy that the surface of the carbon nanoparticles of the present invention has oxygen-containing functional groups, namely -OH, -COOH or COC.

[0054] See also Figure 1 As shown, the specific steps are as follows:

[0055] Step 1) Take a number of graphite rods with a conductivity of 14.2 MΩ·cm -1 Pure water cleaning;

[0056] Step 2) Place the cleaned graphite rod in an electrolyte, using pure water as the electrolyte, and its conductivity must be 18.2 MΩ·cm -1 The two graphite rods are kept at a distance of 8 cm; the graphite rods used can be added according to the length of the preparation device.

[0057] Step 3) Connect a positive electrode in parallel to the graphite rod to form a loop with the platinum wire electrode at the bottom of the device, apply a voltage of 50V, and continue electrolysis for 30 days until the electrolyte turns black and the graphite rod is completely etched;

[0058] Step 4) The obtained black electrolyte is filtered once with qualitative filter paper to remove the precipitated graphite oxide and graphite particles, thereby obtaining carbon nanoparticles that can effectively improve the soil properties of saline-alkali land.

[0059] The prepared carbon nanoparticle solution is used to treat saline-alkali soil. The treatment method is as follows: a carbon nanoparticle solution is prepared according to the usage amount of 0.5 g / m2 of carbon nanoparticles, and the solution is evenly poured into the plowed saline-alkali soil. One day later, lettuce and other plants are planted. After 60 days, the plants are removed and soil samples are taken for testing. The carbon nanoparticle solution of the present invention is applied again according to the above dosage, and lettuce is planted to evaluate the effect of soil improvement. After 60 days, soil samples are taken for testing.

[0060] Figure 6 It shows that after 60 days of treatment with carbon nanoparticles, the total nitrogen and hydrolyzed nitrogen in the soil have decreased. After 120 days, the content of total nitrogen and hydrolyzed nitrogen has decreased significantly compared with the control group. There are literature reports that carbon nanoparticles can effectively bind nitrogen. This shows that the carbon nanoparticles applied by the present invention have the same effect, can bind nitrogen in the soil and be used for plant absorption, reduce the nitrogen content of saline-alkali soil, and play a role in improving the soil.

[0061] Figure 7 This is a comparison of soil aggregate structure measured by X-ray diffraction method for soil 60 days and 120 days after treatment. It shows that the number of soil aggregates larger than 100 microns in saline-alkali soil treated with carbon nanoparticles decreased, indicating that the degree of soil compaction decreased significantly, while the number of soil aggregates of 10-50 microns increased significantly, indicating that the aggregate structure of the soil was effectively improved after treatment and the soil permeability was enhanced.

[0062] Figure 8 The results of the microbial flora test on the soil samples after 120 days of treatment show that the types of soil microorganisms treated with the carbon nanoparticles of the present invention increased significantly, and the flora diversity was significantly higher than that of the control group.

[0063] Fig. 9 This is a detailed diagram of the changes in various bacteria. As can be seen from the figure, the bacteria in the pre-treatment group are:

[0064] g__Dongia

[0065] g__Reyranella,

[0066] g__unidentified_Acidimicrobiia Unidentified Acidimicrobiia,

[0067] g__Nocardioides,

[0068] g__Marmoricola,

[0069] g__unidentified_Dehalococcoidia Unidentified Dehalococcoidia,

[0070] g__Tumebacillus,

[0071] g__Solirubrobacter,

[0072] g__Gaiella,

[0073] g__unidentified_Gemmatimonadaceae Unidentified Gemmatimonadaceae,

[0074] g__Gemmatimonas,

[0075] g__Conexibacter,

[0076] g__Hamadaea,

[0077] g__Nitrospira,

[0078] g__Mycobacterium,

[0079] g__Streptomyces,

[0080] g__Hyphomicrobium,

[0081] g__Actinomadura

[0082] Mainly, there are a large number of pathogens, such as Streptomyces, Mycobacterium tuberculosis and so on.

[0083] After being treated with the carbon nanoparticles of the present invention, the bacteria in the soil are:

[0084] g__Dokdonella,

[0085] g__unidentified_Chloroflexi Unidentified Chloroflexi,

[0086] g__Acidibacter,

[0087] g__Actinoplanes,

[0088] g__Bacillus,

[0089] g__Sphingomonas,

[0090] g__unidentified_Alphaproteobacteria Unidentified alpha-proteobacteria,

[0091] g__Pseudolabrys,

[0092] g__Crossiella,

[0093] g__Jatrophihabitans,

[0094] g__Haliangium,

[0095] g__Mizugakiibacter,

[0096] g__Rhodanobacter,

[0097] g__Chujaibacter,

[0098] g__Bryobacter,

[0099] g_Acidothermus

[0100] It can be seen that pathogens such as Streptomyces and Mycobacterium tuberculosis before treatment disappeared, while beneficial soil bacteria such as Actinomycetes and Bacillus were significantly enriched compared with the untreated group.

[0101] Fig.10 A graph showing the difference in soil fungal communities after treatment with carbon nanoparticles. As shown in the figure, the fungal differences are small, and most of the fungal compositions are the same. This indicates that this treatment has a significant specific effect on bacteria and is not sensitive to fungi.

[0102] Bacillus, a beneficial soil bacterium that was significantly enriched in this treatment, was further studied. Bacillus was inoculated in a culture medium containing the carbon nanoparticles of the present invention. After 24 hours of culture, live bacteria were taken for scanning electron microscopy analysis. Fig.11 As shown, the upper picture is the untreated group, where the bacteria shrink, showing obvious decreased activity and aging phenotype. Fig.11 The phenotypes after low concentration (1 μg / mL) and higher concentration (2 μg / mL) are shown below the neutralization, respectively, showing that the bacteria still maintain complete cell morphology and the bacterial activity is significantly improved compared to the control group.

[0103] Fig.12 The figure shows a statistical comparison of the number of bacteria in each treatment group after 24 hours, which shows that the bacteria in the untreated group began to age and die in large numbers, while the bacteria in the treated group still maintained a high growth activity and number.

[0104] Fig.13 The results of active oxygen measurement on leaves taken after planting lettuce in the treated soil and untreated soil were compared. The results showed that the accumulation rate of active nitrogen in leaf cells of the treated group was significantly lower than that of the untreated group. This showed that the degree of soil adversity in the treated group was significantly improved.

[0105] Fig.14 This is a comparison of lettuces grown for 60 days. The left one is lettuce grown in untreated soil, and the right one is lettuce grown in improved soil. This shows that the properties of saline-alkali soil have been significantly improved.

[0106] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A carbon nanoparticle that can effectively improve the soil properties of saline-alkali land. It is characterized in that The carbon nanoparticles are obtained by filtering the positive electrode and the negative electrode after passing electricity in the electrolyte for 20-40 days; the positive electrode is composed of a plurality of graphite rods with a spacing of 5-8 cm between each other; the negative electrode is composed of a platinum wire electrode plate; the electrolyte is selected from water, and the resistivity is greater than 18.2MΩ·cm -1 ; The voltage of the positive and negative electrodes is 10-100V.

2. The carbon nanoparticles according to claim 1, It is characterized in that The electrolyte also includes one or more of nitrogen, phosphorus and potassium.

3. The carbon nanoparticles according to claim 1, It is characterized in that The particle size of the carbon nanoparticles is 2-6 nm.

4. The carbon nanoparticles according to claim 1, It is characterized in that The carbon nanoparticles have oxygen-containing functional groups on their surfaces.

5. The carbon nanoparticles according to claim 4, It is characterized in that The oxygen-containing functional group is selected from -OH, -COOH or COC.

6. The carbon nanoparticles according to claim 1, It is characterized in that The pH value of the carbon nanoparticles in water is 4-5.

7. The carbon nanoparticles according to claim 1, It is characterized in that The voltage at which the positive electrode and the negative electrode are powered is 10-100V.

8. The carbon nanoparticles according to claim 1, It is characterized in that The filtering method is to use qualitative filter paper for filtering.

9. Use of the carbon nanoparticles according to any one of claims 1 to 8 in treating saline-alkali soil, It is characterized in that The steps include: S1: dissolving carbon nanoparticles in water to obtain a carbon nanoparticle solution; S2: evenly pouring the carbon nanoparticle solution into the plowed saline-alkali soil; S3: After 20-28 hours, plants are planted on the saline-alkali soil described in step S2.

10. The use according to claim 9, It is characterized in that The amount of carbon nanoparticles poured into the saline-alkali soil is 0.5 g / m2.

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