Peanut shell biochar soil conditioner modified based on ultrasonic-impregnation method

Abstract

The invention discloses a modified peanut shell biochar soil conditioner based on an ultrasonic-impregnation method, the conditioner is prepared by loading nano-selenium on peanut shell biochar, the conditioner comprises the following raw materials: peanut shell, nano-selenium and distilled water, and the nano-selenium is uniformly loaded on the surface and in pores of the peanut shell biochar through the ultrasonic-impregnation method. The invention relates to the technical field of soil pollution remediation and conditioning, in particular to a peanut shell biochar soil conditioner based on ultrasonic-impregnation method modification, and by adopting the technical scheme, the peanut shell biochar soil conditioner has the following advantages that raw materials are environmentally friendly, modification is efficient, dual functions are achieved, and universality is high.

Description

Technical Field

[0001] The present invention relates to the technical field of soil pollution remediation and conditioning, and in particular to a peanut shell biochar soil conditioner modified based on an ultrasonic-impregnation method. Background Art

[0002] Soil cadmium (Cd) pollution poses a serious threat to farmland ecosystems and food safety, especially in acidic soils where Cd is highly active and easily absorbed and accumulated by crops. Vegetable crops such as chives have a strong ability to accumulate Cd, and green and efficient remediation technologies are urgently needed. Biochar has potential in heavy metal passivation due to its porous structure and rich functional groups, but the passivation effect of ordinary biochar on Cd is limited. Nano-selenium (Nano-Se) has both metal chelating ability and plant nutrition function, and can achieve the dual effects of "passivating Cd and providing Se nutrients" by modifying biochar. However, existing biochar modification methods have problems such as low loading efficiency and poor uniformity, and there is an urgent need to develop efficient and environmentally friendly modification processes. Summary of the Invention

[0003] In view of this, the embodiment of the present invention hopes to provide a peanut shell biochar soil conditioner modified by ultrasound-impregnation method to solve or alleviate the technical problems existing in the prior art and at least provide a beneficial option.

[0004] The purpose of the present invention can be achieved through the following technical measures: a peanut shell biochar soil conditioner modified by ultrasonic-impregnation method, wherein the conditioner is prepared by loading nano-selenium on peanut shell biochar, and the raw materials include: peanut shells, nano-selenium and distilled water, and the nano-selenium is evenly loaded on the surface and pores of the peanut shell biochar by ultrasonic-impregnation method.

[0005] The purpose of the present invention can also be achieved by the following technical measures:

[0006] The mass ratio of the nano-selenium to distilled water is 1:40, and the solid-liquid ratio of the peanut shell biochar to the nano-selenium impregnation solution is 1:(20-60) g / mL.

[0007] The purpose of the present invention can also be achieved by the following technical measures:

[0008] The peanut shells were crushed through a 100-mesh sieve, calcined at 500° C. for 2-4 hours without oxygen, and cooled to obtain peanut shell biochar.

[0009] The object of the present invention can also be achieved by the following technical measures: the ultrasonic-immersion modification treatment step comprises:

[0010] (1) Add nano-selenium to distilled water and ultrasonically disperse for 10-30 minutes to form a nano-selenium solution;

[0011] (2) adding peanut shell biochar and subjecting to ultrasonic shaking treatment at 30-50°C for 1-3 hours;

[0012] (3) After standing for 24 hours, the supernatant was poured out, the solid was washed with distilled water, dried at 80°C to constant weight, and crushed through a 100-mesh sieve.

[0013] The purpose of the present invention can also be achieved by the following technical measures:

[0014] The preferred temperature for the ultrasonic oscillation treatment in step (2) is 40° C., and the treatment time is 2 hours.

[0015] The purpose of the present invention can also be achieved by the following technical measures:

[0016] The weight percentage of the nano-selenium in the conditioning agent is 1.74%. After modification, the biochar has a rough surface and an irregular pore structure and is loaded with nano-selenium particles.

[0017] The object of the present invention can also be achieved by the following technical measures: a method for preparing a soil conditioner, comprising the following steps:

[0018] Step 1: crush the peanut shells through a 100-mesh sieve and calcine them at 500°C in the absence of oxygen for 2-4 hours to prepare peanut shell biochar;

[0019] Step 2: Prepare a nano-selenium solution at a mass ratio of 1:40 between nano-selenium and distilled water, and ultrasonically disperse for 10-30 minutes;

[0020] Step 3: Add peanut shell biochar to the nano-selenium solution at a solid-liquid ratio of 1: (20-60) g / mL, ultrasonically shake at 30-50°C for 1-3 hours, and let it stand for 24 hours;

[0021] Step 4: Pour off the supernatant, wash the solid with distilled water 2-3 times, dry it at 80°C to constant weight, and grind it through a 100-mesh sieve to obtain a modified peanut shell biochar soil conditioner.

[0022] The purpose of the present invention can also be achieved by the following technical measures:

[0023] The calcination time of peanut shell biochar in step 1 is 3 hours, the ultrasonic vibration treatment temperature in step 3 is 40°C, the treatment time is 2 hours, and the solid-liquid ratio is 1:40 g / mL.

[0024] The purpose of the present invention can also be achieved by the following technical measures:

[0025] The conditioner is evenly mixed into cadmium-contaminated soil at a ratio of 1 / 50 of the weight of the soil to reduce the effective cadmium content in the soil and the absorption of cadmium by crops.

[0026] The purpose of the present invention can also be achieved by the following technical measures:

[0027] The cadmium concentration of the cadmium-contaminated soil is 10 mg / kg. After applying the conditioner, the effective cadmium content in the soil is reduced by ≥47.7%, the cadmium content in crop roots is reduced by ≥40.43%, and the cadmium content in leaves is reduced by ≥61.23%.

[0028] The embodiment of the present invention adopts the above technical solution, which has the following advantages:

[0029] 1. Environmentally friendly raw materials: Using agricultural waste peanut shells as raw materials, we can achieve resource utilization with low cost.

[0030] 2. Efficient modification: Ultrasonic-assisted impregnation method ensures uniform loading of nano-selenium, increases active sites on the biochar surface, and enhances cadmium adsorption and plant stress resistance.

[0031] 3. Dual functions: Simultaneously achieve soil cadmium passivation and crop selenium nutrition enhancement to ensure the safety and nutritional value of agricultural products.

[0032] 4. Strong universality: It is suitable for acidic cadmium-contaminated soil and can be extended to other heavy metal pollution remediation and various crop planting.

[0033] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 This is a flow chart of a specific embodiment of a method for preparing a peanut shell biochar soil conditioner modified by ultrasound-impregnation method according to the present invention;

[0036] Figure 2 This is a schematic diagram of the SEM-EDS characterization of the modified biochar of the present invention;

[0037] Figure 3 This is a schematic diagram of the change in cadmium content in shallots of the present invention. DETAILED DESCRIPTION

[0038] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and description are to be considered as illustrative in nature and not restrictive.

[0039] It should be noted that the terms "first," "second," "symmetrical," "array," etc. are used only to distinguish descriptions from positional descriptions and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, limitations on features such as "first" and "symmetrical" may explicitly or implicitly include one or more of these features; similarly, when the number of certain features is not limited in the form of words such as "two" or "three," it should be noted that these features also explicitly or implicitly include one or more of the number of features.

[0040] In the present invention, unless otherwise expressly specified or limited, terms such as "installation," "connection," and "fixation" should be understood broadly; for example, they may refer to fixed connection, detachable connection, or integral molding; they may refer to mechanical connection, direct connection, welding, or indirect connection through an intermediate medium; they may refer to internal communication between two components or interaction between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on the specification and drawings in conjunction with specific circumstances.

[0041] The embodiments of the present invention are described in detail below.

[0042] The invention discloses a peanut shell biochar soil conditioner modified by an ultrasonic-impregnation method. The conditioner is prepared by loading nano-selenium on peanut shell biochar. The raw materials include peanut shells, nano-selenium and distilled water. The nano-selenium is uniformly loaded on the surface and pores of the peanut shell biochar by the ultrasonic-impregnation method. The mass ratio of nano-selenium to distilled water is 1:40, and the solid-liquid ratio of peanut shell biochar to nano-selenium impregnation solution is 1:(20-60) g / mL. The peanut shells are crushed and passed through a 100-mesh sieve, and then oxygen-free calcined at 500° C. for 2-4 hours. The peanut shell biochar is cooled to obtain the peanut shell biochar.

[0043] like Figure 1-3 As shown, the peanut shell biochar soil conditioner based on ultrasonic-impregnation modification of the present invention comprises the following steps:

[0044] (1) Add nano-selenium to distilled water and ultrasonically disperse for 10-30 minutes to form a nano-selenium solution;

[0045] (2) adding peanut shell biochar and subjecting to ultrasonic shaking treatment at 30-50°C for 1-3 hours;

[0046] (3) After standing for 24 hours, the supernatant was poured out, the solid was washed with distilled water, dried at 80°C to constant weight, and crushed through a 100-mesh sieve.

[0047] The preferred temperature for ultrasonic oscillation treatment in step (2) is 40° C., the treatment time is 2 hours, the weight percentage of nano-selenium in the conditioning agent is 1.74%, and the modified biochar has a rough surface, an irregular pore structure, and is loaded with nano-selenium particles.

[0048] A method for preparing a peanut shell biochar soil conditioner modified by an ultrasonic-impregnation method, the method comprising the following steps:

[0049] Step 1: crush the peanut shells through a 100-mesh sieve and calcine them at 500°C in the absence of oxygen for 2-4 hours to prepare peanut shell biochar;

[0050] Step 2: Prepare a nano-selenium solution at a mass ratio of 1:40 between nano-selenium and distilled water, and ultrasonically disperse for 10-30 minutes;

[0051] Step 3: Add peanut shell biochar to the nano-selenium solution at a solid-liquid ratio of 1: (20-60) g / mL, ultrasonically shake at 30-50°C for 1-3 hours, and let it stand for 24 hours;

[0052] Step 4: Pour off the supernatant, wash the solid with distilled water 2-3 times, dry it at 80°C to constant weight, and grind it through a 100-mesh sieve to obtain a modified peanut shell biochar soil conditioner.

[0053] The calcination time of peanut shell biochar in step 1 is 3 hours, the ultrasonic vibration treatment temperature in step 3 is 40°C, the treatment time is 2 hours, and the solid-liquid ratio is 1:40 g / mL.

[0054] A method for applying a peanut shell biochar soil conditioner modified by an ultrasonic-impregnation method includes uniformly mixing the conditioner into cadmium-contaminated soil at a ratio of 1 / 50 of the soil weight, to reduce the effective cadmium content in the soil and the absorption of cadmium by crops. The cadmium concentration in the cadmium-contaminated soil is 10 mg / kg. After application of the conditioner, the effective cadmium content in the soil decreases by ≥47.7%, the cadmium content in the crop roots decreases by ≥40.43%, and the cadmium content in the leaves decreases by ≥61.23%.

[0055] The following are several specific embodiments of the present invention:

[0056] Example 1 (preferred parameter preparation)

[0057] 500g of peanut shells were crushed through a 100-mesh sieve, calcined at 500℃ in the absence of oxygen for 3 hours, and cooled to obtain 200g of peanut shell biochar (BC); 5g of nano-selenium was weighed and added to 200mL of distilled water (mass ratio 1:40). After ultrasonic dispersion for 20 minutes, BC was added at a solid-liquid ratio of 1:40g / mL, and ultrasonically shaken at 40℃ for 2 hours. After standing for 24 hours, the supernatant was poured out, the solid was washed twice with distilled water, dried at 80℃, crushed and sieved to obtain modified biochar (Se-BC-1) with a nano-selenium content of 1.74%. 10 kg of cadmium-contaminated soil (Cd concentration 10 mg / kg) was taken, Se-BC-1 was applied at a ratio of 1:50, and chives were planted. After 30 days, the test showed that the effective cadmium content in the soil was reduced by 47.70% compared with the control group, the cadmium content in the roots and leaves of the chives decreased by 40.43% and 61.23% respectively, the selenium content in the leaves increased by 1.9 times compared with the control, the superoxide staining area of ​​the roots (4.94%) was close to the non-stress level (3.31% in the CK group), and the chloroplast thylakoid structure was intact.

[0058] Example 2 (solid-liquid ratio 1:20 g / mL)

[0059] 200g of peanut shell biochar was prepared, and 10g of nano-selenium was weighed and added to 200mL of distilled water (mass ratio 1:20). After ultrasonic dispersion for 10 minutes, the mixture was mixed with BC at a solid-to-liquid ratio of 1:20g / mL. The mixture was ultrasonically shaken at 30°C for 1 hour, and subsequently treated as in Example 1 to produce modified biochar (Se-BC-2, nano-selenium content 1.52%). After application under the same conditions, the available cadmium content in the soil decreased by 35.50%, the cadmium content in the roots and leaves of shallots decreased by 26.09% and 27.27%, respectively, and the selenium content in the leaves increased by 1.5 times. The stomatal structure recovered compared to the control group (CG group), but some collapse still existed.

[0060] Example 3 (solid-liquid ratio 1:60 g / mL)

[0061] 3.33g of nano-selenium was weighed and added to 200mL of distilled water (mass ratio 1:60). After ultrasonic dispersion for 30 minutes, the mixture was mixed with 200g of BC at a solid-to-liquid ratio of 1:60g / mL. The mixture was ultrasonically shaken at 50°C for 3 hours and subsequently treated as in Example 1 to produce modified biochar (Se-BC-3, nano-selenium content 1.65%). Post-application testing showed a 42.68% decrease in available cadmium in the soil, a 33.70% decrease in cadmium levels in the roots and leaves of shallots, and a 1.6-fold increase in selenium content in the leaves. The chloroplast morphology of the mesophyll cells was significantly improved compared to the control group, and the thylakoid lamellae structure became more regular but slightly less uniform than in Example 1.

[0062] Comparative Description of Examples

[0063] All three examples successfully prepared nano-selenium-modified peanut shell biochar by the ultrasonic-impregnation method. Among them, Example 1 adopted the preferred process parameters (solid-liquid ratio of 1:40, ultrasound at 40°C for 2 hours), and had the best passivation effect on soil cadmium (effective cadmium reduction of 47.70%) and crop cadmium absorption inhibition (leaf reduction of 61.23%), and significantly repaired cell ultrastructure damage; Examples 2 and 3 verified the applicability of the process parameters in a wide range by adjusting the solid-liquid ratio and treatment conditions. The results showed that the nano-selenium loading amount and the ultrasonic treatment conditions synergistically affected the performance of the conditioner, providing a basis for optimizing the process according to the degree of pollution in practical applications.

[0064] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various modifications and substitutions within the technical scope disclosed in the present invention, and such modifications and substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A peanut shell biochar soil conditioner modified by ultrasonic-impregnation method, characterized in that: The conditioning agent is prepared by loading nano-selenium on peanut shell biochar. The raw materials include peanut shell, nano-selenium and distilled water. The nano-selenium is evenly loaded on the surface and pores of the peanut shell biochar through an ultrasonic-impregnation method.

2. The peanut shell biochar soil conditioner modified by ultrasonic-impregnation method according to claim 1, characterized in that: The mass ratio of the nano-selenium to distilled water is 1:40, and the solid-liquid ratio of the peanut shell biochar to the nano-selenium impregnation solution is 1:(20-60) g / mL.

3. The peanut shell biochar soil conditioner modified by ultrasonic-impregnation method according to claim 1, characterized in that: The peanut shells were crushed through a 100-mesh sieve, calcined at 500° C. for 2-4 hours without oxygen, and cooled to obtain peanut shell biochar.

4. The peanut shell biochar soil conditioner modified by ultrasonic-impregnation method according to claim 1, characterized in that: The ultrasonic-immersion modification treatment step comprises: (1) Add nano-selenium to distilled water and ultrasonically disperse for 10-30 minutes to form a nano-selenium solution; (2) adding peanut shell biochar and subjecting to ultrasonic shaking treatment at 30-50°C for 1-3 hours; (3) After standing for 24 hours, the supernatant was poured out, the solid was washed with distilled water, dried at 80°C to constant weight, and crushed through a 100-mesh sieve.

5. A peanut shell biochar soil conditioner modified by ultrasonic-impregnation method as claimed in claim 4, characterized in that: The preferred temperature for the ultrasonic oscillation treatment in step (2) is 40° C., and the treatment time is 2 hours.

6. A peanut shell biochar soil conditioner modified by ultrasound-impregnation method according to any one of claims 1 to 5, characterized in that: The weight percentage of the nano-selenium in the conditioning agent is 1.74%. After modification, the biochar has a rough surface and an irregular pore structure and is loaded with nano-selenium particles.

7. A method for preparing a peanut shell biochar soil conditioner based on ultrasonic-impregnation modification according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: crush the peanut shells through a 100-mesh sieve and calcine them at 500°C in the absence of oxygen for 2-4 hours to prepare peanut shell biochar; Step 2: Prepare a nano-selenium solution at a mass ratio of 1:40 between nano-selenium and distilled water, and ultrasonically disperse for 10-30 minutes; Step 3: Add peanut shell biochar to the nano-selenium solution at a solid-liquid ratio of 1: (20-60) g / mL, ultrasonically shake at 30-50°C for 1-3 hours, and let it stand for 24 hours; Step 4: Pour off the supernatant, wash the solid with distilled water 2-3 times, dry it at 80°C to constant weight, and grind it through a 100-mesh sieve to obtain a modified peanut shell biochar soil conditioner.

8. The method for preparing a peanut shell biochar soil conditioner modified by ultrasonic-impregnation method according to claim 7, characterized in that: The calcination time of peanut shell biochar in step 1 is 3 hours, the ultrasonic vibration treatment temperature in step 3 is 40°C, the treatment time is 2 hours, and the solid-liquid ratio is 1:40 g / mL.

9. A method for applying peanut shell biochar soil conditioner modified by ultrasound-impregnation method as claimed in any one of claims 1 to 6, characterized in that: The conditioner is evenly mixed into cadmium-contaminated soil at a ratio of 1 / 50 of the weight of the soil to reduce the effective cadmium content in the soil and the absorption of cadmium by crops.

10. The method for applying peanut shell biochar soil conditioner modified by ultrasonic-impregnation method according to claim 9, characterized in that: The cadmium concentration of the cadmium-contaminated soil is 10 mg / kg. After applying the conditioner, the effective cadmium content in the soil decreases by ≥47.7%, the cadmium content in crop roots decreases by ≥40.43%, and the cadmium content in leaves decreases by ≥61.23%.

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