A preparation process of carbon quantum dots, carbon quantum dots, agricultural composition and application thereof

Abstract

The present invention relates to the field of nanomaterial technology, and in particular to a preparation process of carbon quantum dots, carbon quantum dots, agricultural compositions and their applications. The steps of the preparation process of the carbon quantum dots are as follows: reacting aniline derivatives or biochar in a nitrogen environment to obtain a solution and then centrifuging it; taking the supernatant and dialyzing it to obtain carbon quantum dots. The carbon quantum dots and agricultural compositions provided by the present invention can exist in the soil for a long time, are easily absorbed by the root system, and exert their effects quickly and for a long time.

Description

Technical Field

[0001] The present invention relates to the technical field of nanomaterials, and in particular to a preparation process of carbon quantum dots, carbon quantum dots, an agricultural composition and applications thereof. Background Art

[0002] At present, carbon nanoparticles with a particle size of less than 10nm and fluorescent characteristics are called carbon dots. Based on the differences in the carbon core, carbon dots are divided into five categories: graphene quantum dots, graphene carbon nitrogen quantum dots, carbon quantum dots, carbon nanodots and carbon polymer dots. The carbon core of graphene quantum dots is usually composed of one or several atomic layers of graphene and usually contains some functional groups at its edge sites; similar to graphene quantum dots, the carbon core of graphene carbon nitrogen quantum dots is usually composed of one or several atomic layers of carbon nitrogen and usually contains -NH2 at the edge; carbon quantum dots are quasi-spherical carbon nanoparticles, which have a crystalline core, and the core is usually SP 2 Hybridized carbon embedded in SP 3 Hybridized carbon medium.

[0003] Nanofertilizer is a branch of nanobiotechnology. It is a new type of fertilizer containing nanocarbon, which is constructed using nanomaterial technology, including nanostructured fertilizers and nanomaterial coated controlled release fertilizers. Water-wetting nanofertilizer particles have a large contact area with the soil. On the one hand, they can quickly absorb water, increase the solubility of water, improve the cell biological permeability of water, improve the absorption of fertilizers by plants, and reduce the loss and fixation of applied fertilizers.

[0004] Current research has found that carbon quantum dots are applied in the agricultural field, and foliar spraying is more effective than fertilizers because of their small particle size, which can quickly penetrate the leaf surface to exert their effects. At the same time, in order to enhance the effect of carbon quantum dots, their surface is often modified to add more hydrophilic groups, but this also accelerates their loss in the soil or leaf surface. In view of this phenomenon, the present invention provides a preparation process for carbon quantum dots, carbon quantum dots, agricultural compositions and their applications, which can effectively exert the effect of carbon quantum dots for a long time. Summary of the invention

[0005] The object of the present invention is to provide a process for preparing carbon quantum dots, the steps of the preparation process are as follows:

[0006] Aniline derivatives or biochar are reacted in a nitrogen environment to obtain a solution, which is then centrifuged; the supernatant is dialyzed to obtain carbon quantum dots.

[0007] As an embodiment of the present invention, the aniline derivative is selected from one of p-aminobenzenesulfonic acid, p-aminobenzamide, 3-aminobenzaldehyde, m-phenylenediamine and diphenylamine.

[0008] As an embodiment of the present invention, the source of the biochar is algae or seed plants.

[0009] As an embodiment of the present invention, the reaction conditions are: temperature of 185° C.; constant temperature reaction time of 14 h; temperature gradient of 1.5° C. / min; natural cooling.

[0010] A second aspect of the present invention provides a carbon quantum dot, which is prepared by the above-mentioned carbon quantum dot preparation process.

[0011] The third aspect of the present invention provides an agricultural composition, characterized in that it comprises the carbon quantum dots and a cationic polymer.

[0012] As an embodiment of the present invention, the mass ratio of the carbon quantum dots to the cationic polymer is 1:(0.01-0.2).

[0013] As an embodiment of the present invention, the molecular weight of the cationic polymer is 8 million or 12 million.

[0014] The fourth aspect of the present invention provides the agricultural composition, which is applied in the field of agricultural fertilizers.

[0015] By adopting the above technical solution, the present invention has the following beneficial effects:

[0016] The carbon quantum dots and agricultural compositions provided by the present invention can exist in the soil for a long time, are easily absorbed by the root system, and exert their effects quickly and for a long time. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0018] The present invention provides a preparation process of carbon quantum dots, characterized in that the preparation process steps are as follows:

[0019] Aniline derivatives or biochar are reacted in a nitrogen environment to obtain a solution, which is then centrifuged; the supernatant is dialyzed to obtain carbon quantum dots.

[0020] Specifically, the preparation process steps of the carbon quantum dots are as follows:

[0021] Dissolve 65 mg of p-aminobenzamide in 10 ml of ultrapure water, stir for 3 hours, pour into a reactor, and react at 185°C for 6 hours under a nitrogen environment with a temperature gradient of 1.5°C / min; cool naturally, and perform high-speed centrifugation on the reaction solution. Take the supernatant and dialyze it in a 500Da dialysis bag for 24 hours. Replace the dialyzed water every 6 hours to obtain carbon quantum dots.

[0022] As a preferred embodiment of the present invention, the carbon quantum dots are further selenium-modified carbon quantum dots, and the further preparation process is as follows:

[0023] Dissolve 65 mg of p-aminobenzamide and 20 mg of phenylselenol in 10 ml of ultrapure water, stir for 3 hours, pour into a reactor, and react at a constant temperature of 185°C for 6 hours under a nitrogen environment with a temperature gradient of 1.5°C / min; cool naturally, and perform high-speed centrifugation on the reaction solution. Take the supernatant and dialyze it in a 500Da dialysis bag for 24 hours. Replace the dialyzed water every 2 hours to obtain doped carbon quantum dots.

[0024] 100 mg of doped carbon quantum dots were dispersed in Na2SeO3 solution (the mass ratio of C and Se was 1:1), and the reaction was shaken for 24 hours; 0.5 g of sodium thiosulfate was added to the reaction solution, and the resulting solution was centrifuged at high speed to obtain a solid, which was dried to obtain selenium-modified carbon quantum dots.

[0025] The second aspect of the present invention provides an agricultural composition, which comprises the carbon quantum dots and cationic polymers; the mass ratio of the carbon quantum dots to the cationic polymers is 1:(0.01-0.2); more preferably, when the molecular weight of the cationic polymer is 8 million, the mass ratio is 1:0.015; when the molecular weight of the cationic polymer is 12 million, the mass ratio is 1:0.01.

[0026] A second aspect of the present invention provides an agricultural composition for use in the field of agricultural fertilizers.

[0027] The third aspect of the present invention provides a method for using the agricultural composition. When using the agricultural composition as a fertilizer, the agricultural composition provided by the present invention is mixed with the fertilizer and then applied to the soil. More preferably, the agricultural composition provided by the present invention is suitable for the use of phosphorus-containing pesticides during crop growth. For example, phosphorus-containing herbicides, phosphorus-containing insecticides, etc. The phosphorus-containing pesticide refers to the original drug in the pesticide preparation that has a pharmacological effect and contains a phosphorus group; more preferably, it refers to the group on the original drug that has a pharmacological effect containing phosphorus.

[0028] The inventors of this application have found that carbon quantum dots are better for foliar spraying than for soil; however, the physical properties of carbon quantum dots themselves can play a greater role as fertilizers. The present invention uses an agricultural composition containing carbon quantum dots, which can exist for a long time in the soil and is particularly suitable for mixed use with phosphorus-containing pesticides. The reason is that conventionally used carbon quantum dots will add hydrophilic groups to the surface in order to improve water solubility; however, for the soil, it forms a negative charge, which often causes the interaction between the soil and the carbon quantum dots to be weak. The present invention adds a cationic polymer that plays a bridging role to the carbon quantum dot composition; however, the inventors have found that some pesticides are often used in pesticides, and for the use of phosphorus-containing pesticides, this formula will compete with the addition of phosphorus-containing pesticides, resulting in a decrease in effect. For this reason, the present invention uses a long carbon chain cationic polymer, which increases steric hindrance while expanding the "action circle" formed with the soil, thereby reducing the influence of phosphorus pesticides added later. At the same time, because of the interaction with the soil, the action time of the carbon quantum dots and the root system is increased, so that the efficacy is improved.

[0029] The present invention is further explained below in conjunction with specific implementation modes.

[0030] Example 1

[0031] This embodiment provides an agricultural composition, which includes modified carbon quantum dots and cationic polymers, and the mass ratio of the two is 1:0.01.

[0032] Wherein, the preparation process of the modified carbon quantum dots is as follows:

[0033] Dissolve 65 mg of p-aminobenzamide and 20 mg of phenylselenol in 10 ml of ultrapure water, stir for 3 hours, pour into a reactor, and react at a constant temperature of 185°C for 6 hours under a nitrogen environment with a temperature gradient of 1.5°C / min; cool naturally, and perform high-speed centrifugation on the reaction solution. Take the supernatant and dialyze it in a 500Da dialysis bag for 24 hours. Replace the dialyzed water every 2 hours to obtain doped carbon quantum dots.

[0034] 100 mg of doped carbon quantum dots were dispersed in Na2SeO3 solution (the mass ratio of C and Se was 1:1), and the reaction was shaken for 24 hours; 0.5 g of sodium thiosulfate was added to the reaction solution, and the resulting solution was centrifuged at high speed to obtain a solid, which was dried to obtain selenium-modified carbon quantum dots.

[0035] The cationic polymer is cationic polyacrylamide with a molecular weight of 12 million.

[0036] Comparative Example 1

[0037] This embodiment provides an agricultural composition, which includes modified carbon quantum dots and cationic polymers, and the mass ratio of the two is 1:0.01.

[0038] Wherein, the preparation process of the modified carbon quantum dots is as follows:

[0039] Dissolve 65 mg of p-aminobenzamide in 10 ml of ultrapure water, stir for 3 hours, pour into a reactor, and react at 185°C for 6 hours under a nitrogen environment with a temperature gradient of 1.5°C / min; cool naturally, and perform high-speed centrifugation on the reaction solution. Take the supernatant and dialyze it in a 500Da dialysis bag for 24 hours. Replace the dialyzed water every 6 hours to obtain carbon quantum dots.

[0040] The cationic polymer is cationic polyacrylamide with a molecular weight of 12 million.

[0041] Comparative Example 2

[0042] This embodiment provides an agricultural composition, which includes modified carbon quantum dots and cationic polymers, and the mass ratio of the two is 1:0.01.

[0043] Wherein, the preparation process of the modified carbon quantum dots is as follows:

[0044] Dissolve 65 mg of p-aminobenzamide and 20 mg of phenylselenol in 10 ml of ultrapure water, stir for 3 hours, pour into a reactor, and react at a constant temperature of 185°C for 6 hours under a nitrogen environment with a temperature gradient of 1.5°C / min; cool naturally, and perform high-speed centrifugation on the reaction solution. Take the supernatant and dialyze it in a 500Da dialysis bag for 24 hours. Replace the dialyzed water every 2 hours to obtain doped carbon quantum dots.

[0045] The cationic polymer is cationic polyacrylamide with a molecular weight of 12 million.

[0046] Comparative Example 3

[0047] This embodiment provides an agricultural composition comprising modified carbon quantum dots.

[0048] Wherein, the preparation process of the modified carbon quantum dots is as follows:

[0049] Dissolve 65 mg of p-aminobenzamide and 20 mg of phenylselenol in 10 ml of ultrapure water, stir for 3 hours, pour into a reactor, and react at a constant temperature of 185°C for 6 hours under a nitrogen environment with a temperature gradient of 1.5°C / min; cool naturally, and perform high-speed centrifugation on the reaction solution. Take the supernatant and dialyze it in a 500Da dialysis bag for 24 hours. Replace the dialyzed water every 2 hours to obtain doped carbon quantum dots.

[0050] 100 mg of doped carbon quantum dots were dispersed in Na2SeO3 solution (the mass ratio of C and Se was 1:1), and the reaction was shaken for 24 hours; 0.5 g of sodium thiosulfate was added to the reaction solution, and the resulting solution was centrifuged at high speed to obtain a solid, which was dried to obtain selenium-modified carbon quantum dots.

[0051] Comparative Example 4

[0052] This embodiment provides an agricultural composition, which includes modified carbon quantum dots and cationic polymers, and the mass ratio of the two is 1:0.015.

[0053] Wherein, the preparation process of the modified carbon quantum dots is as follows:

[0054] Dissolve 65 mg of p-aminobenzamide and 20 mg of phenylselenol in 10 ml of ultrapure water, stir for 3 hours, pour into a reactor, and react at a constant temperature of 185°C for 6 hours under a nitrogen environment with a temperature gradient of 1.5°C / min; cool naturally, and perform high-speed centrifugation on the reaction solution. Take the supernatant and dialyze it in a 500Da dialysis bag for 24 hours. Replace the dialyzed water every 2 hours to obtain doped carbon quantum dots.

[0055] 100 mg of doped carbon quantum dots were dispersed in Na2SeO3 solution (the mass ratio of C and Se was 1:1), and the reaction was shaken for 24 hours; 0.5 g of sodium thiosulfate was added to the reaction solution, and the resulting solution was centrifuged at high speed to obtain a solid, which was dried to obtain selenium-modified carbon quantum dots.

[0056] The cationic polymer is cationic polyacrylamide with a molecular weight of 8 million.

[0057] Comparative Example 5

[0058] This embodiment provides an agricultural composition, which includes modified carbon quantum dots and cationic polymers, and the mass ratio of the two is 1:0.012.

[0059] Wherein, the preparation process of the modified carbon quantum dots is as follows:

[0060] Dissolve 65 mg of p-aminobenzamide and 20 mg of phenylselenol in 10 ml of ultrapure water, stir for 3 hours, pour into a reactor, and react at a constant temperature of 185°C for 6 hours under a nitrogen environment with a temperature gradient of 1.5°C / min; cool naturally, and perform high-speed centrifugation on the reaction solution. Take the supernatant and dialyze it in a 500Da dialysis bag for 24 hours. Replace the dialyzed water every 2 hours to obtain doped carbon quantum dots.

[0061] 100 mg of doped carbon quantum dots were dispersed in Na2SeO3 solution (the mass ratio of C and Se was 1:1), and the reaction was shaken for 24 hours; 0.5 g of sodium thiosulfate was added to the reaction solution, and the resulting solution was centrifuged at high speed to obtain a solid, which was dried to obtain selenium-modified carbon quantum dots.

[0062] The cationic polymer is cationic polyacrylamide with a molecular weight of 12 million.

[0063] Comparative Example 6

[0064] This embodiment provides an agricultural composition, which includes modified carbon quantum dots and cationic polymers, and the mass ratio of the two is 1:0.01.

[0065] Wherein, the preparation process of the modified carbon quantum dots is as follows:

[0066] Dissolve 100 mg of selenocystamine hydrochloride and 50 mg of m-phenylenediamine in 10 ml of ultrapure water, stir for 3 hours, pour into a high-pressure reactor, introduce nitrogen to remove oxygen in the reactor, react at 180 ° C for 8 hours, and obtain a brown-yellow solution. Centrifuge at 12000 rpm for 20 minutes. Carefully collect the supernatant, dissolve 1.8 g of polyacrylic acid (PAA) with a relative molecular mass of 1800 in 2 ml of water and mix with the supernatant, slowly drip into 7 ml of ammonia water with a pipette, and stir at 500 rpm for 8 hours. Use a 10000D dialysis bag for purification, replace the dialyzed water every 6-8 hours, and dialyze for 48 hours to obtain modified carbon quantum dots.

[0067] The cationic polymer is cationic polyacrylamide with a molecular weight of 12 million.

[0068] Performance Testing

[0069] The test variety is potato, Haishu No. 1, and the test area is in the temperate zone, with an average annual temperature of 3.3℃, ​​an annual precipitation of 532mm, and a frost-free period of about 134d. The test soil is black soil with a 20cm tillage layer. The soil organic matter content of the test site is 4.76%, alkaline nitrogen is 411mg / kg, available potassium is 324mg / kg, available phosphorus is 101mg / kg, and the pH is about 6.5.

[0070] The experiment set up 12 treatments, each treatment was repeated 3 times, blank control group, Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6, phoxim group, Example 1 + phoxim, Example 4 + phoxim, Example 5 + phoxim. Among them, the application rate of the blank control group, Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, and Comparative Example 6 was 0.5 kg / hm 2 The application rate of phoxim group was 0.05kg / hm 2The application rate of Example 1 + phoxim, Example 4 + phoxim, and Example 5 + phoxim is (0.5 + 0.05) kg / hm 2 .

[0071] The experiment adopted a randomized block design, with a plot length of 16m, a width of 10m, a plant spacing of 25cm, a row spacing of 80cm, and a plot spacing of 1m. The seeds were sown on April 20, 2020, and harvested on September 5. The yield of potatoes was measured at harvest.

[0072] Test 2: Potash fertilizer was added to each group of the above test group, and the amount of potassium fertilizer added was 5kg / hm 2 , and then calculate the potassium fertilizer utilization rate according to the public announcement, potassium fertilizer utilization rate = (potassium uptake by fertilized plants - potassium uptake by control treated plants) / potassium fertilizer application amount × 100%.

[0073] Table 1 Test results

[0074]

[0075] In the above embodiments, the difference from Example 1 is that the carbon quantum dots in Example 1 are not modified; the carbon quantum dots in Example 2 are not loaded and modified; the composition in Example 3 does not contain a cationic polymer; the molecular weight of the cationic polymer in Example 4 is 8 million; the weight of the cationic polymer in Example 5 is adjusted; and the preparation method of the carbon quantum dots in Example 6 is changed. The present invention selects an agricultural composition containing carbon quantum dots, which can exist in the soil for a long time and is particularly suitable for mixed use with phosphorus-containing pesticides.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An agricultural composition for use with a phosphorus-containing pesticide, characterized in that: It contains modified carbon quantum dots and cationic polymers, and the mass ratio of the two is 1:0.01; Wherein, the preparation process of the modified carbon quantum dots is as follows: Dissolve 65 mg of p-aminobenzamide and 20 mg of phenylselenol in 10 ml of ultrapure water, stir for 3 hours, pour into a reactor, and react at 185°C for 6 hours under a nitrogen environment with a temperature gradient of 1.5°C / min; cool naturally, and centrifuge the resulting solution at high speed. Take the supernatant and dialyze it in a 500Da dialysis bag for 24 hours, replacing the dialyzed water every 2 hours to obtain doped carbon quantum dots; 100 mg of doped carbon quantum dots were dispersed in a Na2SeO3 solution with a mass ratio of C to Se of 1:1, and the reaction was oscillated for 24 hours; 0.5 g of sodium thiosulfate was added to the reaction solution, and the resulting solution was centrifuged at high speed to obtain a solid, which was dried to obtain selenium-modified carbon quantum dots; The cationic polymer is cationic polyacrylamide with a molecular weight of 12 million.

Images