A nutrient-type fully degradable mulch film from waste milk sources, its preparation method and application

Abstract

The present invention provides a nutrient-type fully degradable mulching film made from waste milk sources, its preparation method and application, including steps such as converting waste milk into a fulvic acid-like solution, compounding, and air-drying to form a film, belonging to the technical field of agricultural environment. The present invention realizes the resource utilization of waste milk. At the same time, the prepared mulching film has good mechanical properties and meets the actual application requirements. It not only has a good heat preservation and moisture retention effect, but also can slowly release ammonium sulfate and fulvic acid, playing the role of a film-fertilizer dual function. In addition, after the mulching film degrades, it can improve the soil structure.

Description

Technical Field

[0001] The present invention relates to a nutrient-type fully degradable mulching film derived from waste milk, its preparation method and application, belonging to the technical field of agricultural environment. Background Art

[0002] The share of China's mulching film usage in the global market is very large. So far, the global usage of mulching film is about 2 million tons, of which about 75% is in China (about 300 million mu). Since the used mulching film is aged and brittle, it is difficult to recycle (less than 66.67%), which is likely to cause white pollution. Therefore, there is an urgent need to develop degradable mulching films to replace traditional plastic mulching films.

[0003] At the same time, according to statistics, China annually produces up to 5 million tons of waste milk. If directly discharged without treatment, it will not only cause waste of resources but also lead to serious environmental pollution. There is an urgent need to develop new methods for resource utilization. Since milk contains carbohydrates (4-5%), proteins (2.9-3.5%) and lipids (3.8-5.5%), and is rich in nitrogen and phosphorus nutrient elements, if used as a raw material to make a film-fertilizer dual-functional fully degradable mulching film, its nutritional value can be utilized and the white pollution problem of polyethylene mulching film can be solved synchronously.

[0004] Therefore, there is an urgent need in this field for a nutrient-type fully degradable mulching film derived from waste milk, its preparation method and application. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem that the existing mulching film is aged and brittle and difficult to recycle.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is to provide a nutrient-type fully degradable mulching film derived from waste milk, its preparation method and application.

[0007] In the first aspect of the present invention, a preparation method of a nutrient-type fully degradable mulching film derived from waste milk is provided, including the following steps:

[0008] Step 1: Add hydrogen peroxide to waste milk, stir, and irradiate with a medium-pressure ultraviolet mercury lamp at the same time. Through catalytic oxidation, the waste milk is converted into a fulvic acid-like solution;

[0009] Step 2: At 30-40 °C, add zinc oxide powder, ammonium sulfate, arabic gum solution and tributyl citrate to the fulvic acid-like solution obtained in Step 1 in sequence to obtain a compound solution;

[0010] Step 3: At 20-30 °C, evenly spray the compound solution obtained in Step 2 on a glass plate, and irradiate it with a high-energy electron beam, and air-dry it to form a film, that is, a nutrient-type fully degradable mulching film derived from waste milk.

[0011] Preferably, in the step 1, the volume of the waste milk is 100 - 200 mL, the volume of the hydrogen peroxide is 2 - 5 mL, and the mass percentage (W / W) is 20 - 30%; the stirring temperature is 50 - 90 °C, the stirring speed is 100 - 200 rpm, the stirring time is 5 - 10 minutes, and a medium-pressure ultraviolet mercury lamp with parameters of 1 - 2 kW and 200 - 400 nm is used.

[0012] Preferably, in the step 2, 0.6 - 1.0 g of zinc oxide powder with a particle size of 20 - 100 nm; 4 - 8 g of ammonium sulfate; the concentration of the arabic gum solution is 4 - 8 g / L, and the added volume is 3 - 6 mL; the volume of tributyl citrate is 2 - 4 mL, and the addition process is carried out under stirring with a stirring speed of 100 - 200 rpm.

[0013] Preferably, in the step 3, the spraying speed is 0.2 - 0.4 L / min; the area of the glass plate is 1 - 2 square meters; the parameters of the high-energy electron beam are 10 - 20 MeV and 10 - 30 kGy, and the irradiation time is 1 - 2 minutes. The area of the waste milk source nutrient-type fully degradable plastic film obtained is 1 - 2 square meters, and the thickness is 0.3 - 0.6 mm.

[0014] In the second aspect of the present invention, a waste milk source nutrient-type fully degradable plastic film prepared by the above method is provided.

[0015] In the third aspect of the present invention, an application of the above waste milk source nutrient-type fully degradable plastic film in planting is provided.

[0016] Compared with the prior art, the present invention has the following beneficial effects: realizing the resource utilization of waste milk. At the same time, the prepared plastic film has good mechanical properties and meets the actual application requirements. It not only has a good heat preservation and moisture retention effect, but also can slowly release ammonium sulfate and fulvic acid, playing the role of both film and fertilizer. In addition, the plastic film can improve the soil structure after degradation. Description of the Drawings

[0017] Figure 1 It is a diagram of a waste milk source nutrient-type fully degradable plastic film;

[0018] Figure 2 It is a comparison diagram of the plastic film prepared in Example 2 with the blank (without film covering) and the PE film;

[0019] Figure 3 It is a comparison diagram of the mechanical properties of the plastic film prepared in Example 2 and the PE film;

[0020] Figure 4 It is a comparison diagram of the heat preservation effect of the plastic film prepared in Example 2;

[0021] Figure 5 It is a comparison diagram of the germination rate and yield of the plastic film prepared in Example 2;

[0022] Figure 6 Comparison chart of plant height and root length of the plastic film prepared in Example 2;

[0023] Figure 7 Curves of slow-release ammonium sulfate and fulvic acid of the plastic film prepared in Example 2;

[0024] Figure 8 Three-dimensional fluorescence images of the plastic film prepared in Example 2 at 0, 1, 15, 45, 60, and 70 days. Detailed implementation manners

[0025] To make the present invention more obvious and understandable, preferred embodiments are hereby described in detail in conjunction with the accompanying drawings as follows:

[0026] Example 1:

[0027] (1) Add 2 mL of hydrogen peroxide (W / W, 20%) to 100 mL of waste milk, stir at 50 °C (100 rpm) for 5 minutes, and irradiate with a medium-pressure ultraviolet mercury lamp (1 kW, 200 nm) at the same time. Convert the waste milk into a fulvic acid-like solution through catalytic oxidation;

[0028] (2) At 30 °C, add 0.6 g of zinc oxide powder (particle size: 20 nm) to the solution obtained in (1), stir at 30 °C (100 rpm) for 5 minutes, then add 4 g of ammonium sulfate, stir (100 rpm) for 10 minutes, then add 3 mL of gum arabic solution (4 g / L), stir for 5 minutes, and finally add 2 mL of tributyl citrate, stir (100 rpm) for 1 minute.

[0029] (3) At 20 °C, spray the solution obtained in (2) evenly (0.2 L / min) on a 1-square-meter glass plate with a sprayer, and irradiate it with a high-energy electron beam (10 MeV, 10 kGy) for 1 minute, then air-dry to form a film (1 square meter, thickness 0.3 mm).

[0030] (4) Lay the film flat on the soil surface planted with pakchoi, cover the soil around it, and the results of harvesting on the 60th day show that this treatment increases the emergence rate of pakchoi by 35%, the yield by 33.5%, and the plant height by 22.5% compared with the non-film-covered group, and increases the available nitrogen, available phosphorus, available potassium, and organic matter in the soil by 26.8, 137.6, 132.2, and 8.6% respectively, and reduces the bulk density by 8.7%. The ammonium sulfate and fulvic acid are completely released in 60 days, and the film is completely degraded in 90 days.

[0031] Example 2:

[0032] (1) Add 3.5 mL of hydrogen peroxide (W / W, 25%) to 150 mL of waste milk, stir at 70 °C (150 rpm) for 7 minutes, and irradiate with a medium-pressure ultraviolet mercury lamp (1.5 kW, 300 nm) at the same time. Convert the waste milk into a fulvic acid-like solution through catalytic oxidation;

[0033] (2) At 35 °C, add 0.8 g of zinc oxide powder (particle size: 60 nm) to the solution obtained in (1), stir at 35 °C (150 rpm) for 7 minutes, then add 6 g of ammonium sulfate, stir (150 rpm) for 15 minutes, then add 4.5 mL of gum arabic solution (6 g / L), stir for 7 minutes, and finally add 3 mL of tributyl citrate, stir (150 rpm) for 2 minutes.

[0034] (3) At 25 °C, evenly spray the solution obtained in (2) on a 1.5-square-meter glass plate with a spray bottle (0.3 L / min), and irradiate it with a high-energy electron beam (15 MeV, 20 kGy) for 1.5 minutes, then air-dry to form a film (1.5 square meters, thickness 0.45 mm). Lay the film flat on the soil surface planted with pakchoi, cover the soil around it, and the results harvested on the 60th day showed that this treatment increased the emergence rate of pakchoi by 45%, the yield by 44.3%, and the plant height by 34.3% compared with the non-film-covered group, and increased the available nitrogen, available phosphorus, available potassium, and organic matter in the soil by 37.6, 148.2, 142.4, and 13.2% respectively, and reduced the bulk density by 9.1%. The ammonium sulfate and fulvic acid were completely released in 70 days, and the film was completely degraded in 100 days.

[0035] Example 3:

[0036] (1) Add 5 mL of hydrogen peroxide (W / W, 30%) to 200 mL of waste milk, stir at 90 °C (200 rpm) for 10 minutes, and irradiate with a medium-pressure ultraviolet mercury lamp (2 kW, 400 nm) at the same time. Convert the waste milk into a fulvic acid-like solution through catalytic oxidation;

[0037] (2) At 40 °C, add 1.0 g of zinc oxide powder (particle size: 100 nm) to the solution obtained in (1), stir at 40 °C (200 rpm) for 10 minutes, then add 8 g of ammonium sulfate, stir (200 rpm) for 20 minutes, then add 6 mL of gum arabic solution (8 g / L), stir for 10 minutes, and finally add 4 mL of tributyl citrate, stir (200 rpm) for 3 minutes.

[0038] (3) At 30 °C, the solution obtained in (2) was evenly sprayed (0.4 L / min) onto a 2-square-meter glass plate using a spray bottle, and it was irradiated with a high-energy electron beam (20 MeV, 30 kGy) for 2 minutes, and then air-dried to form a film (2 square meters, thickness 0.6 mm).

[0039] (4) The film was laid flat on the soil surface planted with pakchoi, and the surrounding soil was covered. The results harvested on the 60th day showed that this treatment increased the emergence rate of pakchoi by 40%, the yield by 38.9%, and the plant height by 28.4% compared with the non-film-covered group. It also increased the available nitrogen, available phosphorus, available potassium, and organic matter in the soil by 32.2, 142.9, 137.3, and 10.9% respectively, and decreased the bulk density by 8.9%. Ammonium sulfate and fulvic acid were completely released in 80 days, and the film was completely degraded in 120 days.

[0040] Among them, the effect of Example 2 was the best process (the best effect of promoting growth and improving soil). The comparison with the PE film is shown in Table 1:

[0041] Table 1 Comparison of soil indexes between the mulch film prepared in Example 2 and blank (non-film-covered) and PE film

[0042]

[0043] Application Example 1

[0044] The nutrient-type fully degradable mulch film prepared in Example 2 was used for a pot experiment. The prepared mulch film and PE film were laid respectively, and a control experiment was conducted with the soil without laying the mulch film.

[0045] During the pot experiment, at 18:00 every day, a thermo-hygrometer was used to record the temperature and humidity at 5 cm below the soil surface, and the temperature and humidity changes during this period were recorded.

[0046] After detection, the temperature at 5 cm below the soil surface of the waste milk source nutrient-type fully degradable mulch film was on average 0.22 °C higher than that without laying the mulch film and 0.18 °C lower than that of the traditional PE film. At the same time, the soil humidity of the waste milk source nutrient-type fully degradable mulch film decreased more slowly compared with the soil humidity without laying the mulch film. In addition, the fresh weight and plant height of the pakchoi plants with the waste milk source nutrient-type fully degradable mulch film laid were both between those without laying the mulch film and those with the plastic film laid. In particular, the root system of the plants with the waste milk source nutrient-type fully degradable mulch film laid was longer than that with the traditional PE film laid (see Figure 6) This further proves the release of nutrients such as fulvic acid on the prepared plastic film. During the process of conducting the pot experiment, watering in the later stage meets the basic needs of plant growth, and it can be observed that the prepared plastic film will degrade during this process. The above is only the preferred embodiment of the present invention and does not impose any formal or substantial limitations on the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the premise of the present invention, several improvements and supplements can still be made, and these improvements and supplements should also be regarded as within the protection scope of the present invention. Those who are familiar with this professional technology, without departing from the spirit and scope of the present invention, when making some minor changes, modifications and equivalent variations of the evolved form by using the technical content disclosed above, are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a waste milk-derived nutrient-type fully degradable mulch film, characterized in that: The following steps are involved: Step 1, adding hydrogen peroxide to waste milk, stirring, and irradiating with a medium-pressure ultraviolet mercury lamp to convert the waste milk into a fulvic acid-like solution through catalytic oxidation; wherein the volume of the waste milk is 100-200 mL, the volume of the hydrogen peroxide is 2-5 mL, and the mass percentage (W / W) is 20-30%; the stirring temperature is 50-90 degrees Celsius, the stirring speed is 100-200 rpm, the stirring time is 5-10 minutes, the medium-pressure ultraviolet mercury lamp, the parameters are 1-2 kW, 200-400 nm; Step 2: adding zinc oxide powder, ammonium sulfate, gum arabic solution and tributyl citrate to the fulvic acid-like solution obtained in step 1 at 30-40 degrees Celsius to obtain a composite solution; Step 3: At 20-30 degrees Celsius, spray the compound solution obtained in step 2 evenly on a glass plate, irradiate it with a high-energy electron beam, and air-dry it to form a film, i.e., a waste milk-derived nutrient-type fully degradable mulch film.

2. The method for preparing the waste milk-derived nutrient-type fully degradable mulch film according to claim 1, characterized in that: In the step 2, 0.6-1.0 g of zinc oxide powder, particle size: 20-100 nm; 4-8 g of ammonium sulfate; 4-8 g of gum arabic solution concentration of 4-8 g / L, added volume of 3-6 mL; 2-4 mL of tributyl citrate, the addition process is carried out with stirring, and the stirring speed is 100-200 rpm.

3. The method for preparing the waste milk-derived nutrient-type fully degradable mulch film according to claim 1, characterized in that: In the step 3, the spraying speed is 0.2-0.4 L / min; the glass plate area is 1-2 square meters; the high-energy electron beam parameters are 10-20 MeV, 10-30 kGy, and the irradiation time is 1-2 minutes. The obtained waste milk source nutrient-type fully degradable mulch has an area of ​​1-2 square meters and a thickness of 0.3-0.6 mm.

4. A waste milk-derived nutrient-type fully degradable mulch film prepared by the method according to any one of claims 1 to 3.

5. Use of the waste milk-derived nutrient-type fully degradable mulch film as claimed in claim 4 in planting.

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