Shrimp shell modified watermelon peel biochar, preparation method and application
Modified biochar was prepared by calcining a mixture of shrimp shells and watermelon rinds, which solved the problem of low phosphorus adsorption capacity in existing biochar technologies and achieved efficient and low-cost phosphorus adsorption and resource recovery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHEAST UNIV
- Filing Date
- 2026-04-01
- Publication Date
- 2026-07-31
AI Technical Summary
Existing biochar has low phosphorus adsorption capacity when treating phosphorus-polluted water bodies, and existing modification technologies are complex and may cause secondary pollution or have poor process controllability.
Modified biochar was prepared by calcining a mixture of shrimp shells and watermelon rinds. The calcium in the shrimp shells was loaded onto the surface of the biochar to enhance its phosphorus adsorption performance.
The preparation method is simple and low-cost, with excellent adsorption performance, which can significantly improve the adsorption capacity of phosphorus and can be used as a slow-release phosphate fertilizer to realize resource recovery and waste utilization.
Smart Images
Figure CN122479710A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of biochar preparation and water pollution control technology, specifically relating to a shrimp shell modified watermelon rind biochar, its preparation method, and its application in treating phosphorus-polluted water bodies. Background Technology
[0002] Phosphorus is a core nutrient element for increasing yields in modern agriculture, a key component of genetic material and energy metabolism in living organisms, and a non-renewable strategic mineral resource. Excessive phosphorus application leads to large amounts of phosphorus entering water bodies via surface runoff, causing eutrophication—hypertrophic algal blooms, frequent algal blooms, and consequently, large-scale fish deaths, severely disrupting the aquatic ecological balance. Against this backdrop, recovering phosphorus from phosphorus-rich water bodies is not only an important way to alleviate resource shortages but also a key means to improve aquatic ecosystems, with biochar adsorption technology showing significant practical value.
[0003] Biochar, as a novel functional material for waste resource utilization, has broad application prospects in pollution remediation fields such as nitrogen and phosphorus removal in water bodies and heavy metal fixation in soil, as well as in resource recycling fields such as carbon sequestration and biomass energy conversion, due to its unique physicochemical properties. However, the surface of raw biochar is rich in negatively charged groups, which electrostatically repel negatively charged phosphate ions, resulting in a low phosphorus adsorption capacity and limiting its application.
[0004] To improve adsorption performance, researchers have developed various modification techniques: The alkaline treatment method uses reagents such as sodium hydroxide to modify the biochar surface, making it positively charged and increasing its specific surface area, thereby enhancing phosphate capture through electrostatic attraction and ligand exchange; the metal loading method loads magnesium, iron, and other ions, utilizing the specific binding of metals with phosphate to improve the effect; for example, magnesium-modified biochar prepared by impregnation with magnesium chloride achieved a total phosphorus removal rate of over 90% in simulated wastewater experiments; the biological treatment method uses food waste and other materials as a substrate to cultivate microorganisms, forming a biofilm to modify the biochar surface, increasing the average pore size to optimize performance.
[0005] However, these technologies still have shortcomings: alkaline treatment and metal loading methods are complex and require chemical reagents, which increases costs and may cause secondary pollution; biological treatment methods have long cycles and the process controllability needs to be improved. Summary of the Invention
[0006] The purpose of this invention is to provide a shrimp shell modified watermelon rind biochar, a preparation method, and its application in treating phosphorus-polluted water bodies. By calcining waste shrimp shells and watermelon rinds, calcium from the shrimp shells is loaded onto the biochar, thereby obtaining modified biochar in a highly efficient and low-cost manner and improving the phosphorus adsorption capacity of the biochar.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: Firstly, a method for preparing shrimp shell-modified watermelon rind biochar is provided, comprising: S1. After dehydrating and drying the watermelon rind, grind it into powder to obtain watermelon rind powder; S2. After drying the shrimp shells, grind them into powder to obtain shrimp shell powder; S3. Mix watermelon rind powder and shrimp shell powder, and calcine the resulting mixture at high temperature to obtain shrimp shell modified watermelon rind biochar.
[0008] Further, in step S1, the watermelon rind is placed in a forced-air drying oven at 105°C and dried for 24 hours.
[0009] Furthermore, in step S2, the shrimp shells are washed and then dried in a forced-air drying oven at 105°C for 2 hours.
[0010] Further, in step S3, watermelon rind powder and shrimp shell powder are mixed at a mass ratio of 1:0.5 to 1:2.
[0011] Furthermore, in step S3, when mixing the watermelon rind powder and shrimp shell powder, a vortex shaker is used to shake for 1 minute.
[0012] Further, in step S3, the obtained mixture is calcined in a tube furnace at 700°C for 2 h under an argon atmosphere, with a heating rate of 10°C / min.
[0013] In a second aspect, a shrimp shell modified watermelon rind biochar is provided, which is prepared according to the preparation method of shrimp shell modified watermelon rind biochar according to any one of the first aspects.
[0014] Thirdly, the application of shrimp shell-modified watermelon rind biochar in the treatment of phosphorus-polluted water bodies is provided.
[0015] Furthermore, when treating phosphorus-polluted water bodies with a phosphate concentration of 20-200 mg / L (calculated as phosphorus element), shrimp shell-modified watermelon rind biochar is added to the phosphorus-polluted water body at a dosage of 0.4-1.2 g / L, and the mixture is shaken to complete the adsorption treatment of the phosphorus-polluted water body.
[0016] Furthermore, the oscillation conditions are as follows: oscillate at a rotation speed of 160~200 rpm and at a temperature of 15~35℃ for 2~3 hours.
[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes waste watermelon rinds as raw material, mixes them with waste shrimp shells, and then produces shrimp shell-modified watermelon rind biochar through simple high-temperature calcination. Compared with existing methods for preparing biochar from a single raw material, the biochar formed by calcining the mixture of watermelon rinds and shrimp shells exhibits significantly improved phosphorus adsorption performance due to its abundant surface functional groups and the active sites and metallic components provided by the shrimp shells.
[0018] Compared with other phosphorus adsorption biochars, the shrimp shell-modified watermelon rind biochar of this invention has advantages such as simple preparation method, inexpensive and readily available raw materials, green and environmentally friendly use, and excellent adsorption performance. When used for phosphorus adsorption, it can significantly improve the phosphorus adsorption capacity, and the phosphorus exists in the form of phosphate bound to the active sites on the biochar surface or forming phosphate precipitates, which can be slowly released under specific conditions, thus it can be further used as a slow-release phosphate fertilizer for plants.
[0019] The biomass raw material used in this invention is watermelon rind, an agricultural waste. The modified material uses shrimp shells, a waste product from aquatic product processing, which are made into biochar for phosphorus adsorption. This not only realizes the resource utilization of watermelon rind and shrimp shell waste, but also realizes the resource recovery of phosphorus, which is in line with the concept of circular economy and green development. Attached Figure Description
[0020] Figure 1 The graph shows the maximum equilibrium adsorption capacity of the biochar prepared in Examples 1-3 and Comparative Examples 1 and 2 of this invention. Detailed Implementation
[0021] The present invention will be further described below with reference to specific embodiments. These embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.
[0022] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by those skilled in the art to which this invention pertains.
[0023] Example 1
[0024] A method for preparing shrimp shell-modified watermelon rind biochar includes the following steps: (1) Place the watermelon rind in a 105℃ drying oven for 24 h, and after drying, take it out and crush it with a pulverizer to obtain watermelon rind powder; (2) After cleaning the shrimp shells, place them in a 105℃ drying oven for 2 hours. After drying, take them out and crush them with a pulverizer to obtain shrimp shell powder. (3) Mix watermelon rind powder and shrimp shell powder at a mass ratio of 1:1, and use a vortex shaker to perform medium-intensity shaking for 1 min in a 50 mL centrifuge tube. Place the mixture in a tube furnace and heat it to 700 °C for 2 h at a heating rate of 10 °C / min under an argon atmosphere. After naturally cooling to room temperature, shrimp shell modified watermelon rind biochar is obtained and named SWBC-1.
[0025] Example 2
[0026] A method for preparing shrimp shell modified watermelon rind biochar is the same as that in Example 1, except that the mass ratio of watermelon rind powder to shrimp shell powder in step (3) is 1:0.5, and the resulting shrimp shell modified watermelon rind biochar is named SWBC-0.5.
[0027] Example 3
[0028] A method for preparing shrimp shell modified watermelon rind biochar is the same as that in Example 1, except that the mass ratio of watermelon rind powder to shrimp shell powder in step (3) is 1:2, and the resulting shrimp shell modified watermelon rind biochar is named SWBC-2.
[0029] Comparative Example 1: To conduct effective experimental comparisons, raw watermelon rind biochar material was prepared based on the experimental conditions of Example 1.
[0030] The preparation of raw watermelon rind biochar material is as follows: Watermelon rind powder was placed in a tube furnace and pyrolyzed at 700℃ for 2 h under an argon atmosphere at a heating rate of 10℃ / min. After natural cooling to room temperature, watermelon rind biochar was obtained and named PWR.
[0031] Comparative Example 2 To conduct effective experimental comparisons, raw shrimp shell biochar material was prepared based on the experimental conditions of Example 1.
[0032] The preparation of raw shrimp shell biochar material is as follows: Shrimp shell powder was placed in a tube furnace and pyrolyzed at 700℃ for 2 h under an argon atmosphere at a heating rate of 10℃ / min. After natural cooling to room temperature, shrimp shell biochar was obtained and named PSS.
[0033] Example 4
[0034] Static isothermal adsorption experiments were conducted to compare the adsorption performance of phosphate by raw watermelon rind biochar, raw shrimp shell biochar, and shrimp shell-modified watermelon rind biochar.
[0035] The initial concentration of the phosphate solution, calculated based on phosphorus element, was 100 mg / L. Each biochar material was added to the phosphate solution at a dosage of 1.0 g / L. The solution was shaken at 25℃ and 180 r / min. After 2.5 h, the concentration of the remaining phosphate ions in each solution was measured.
[0036] The adsorption of phosphate by the biochar materials prepared in Examples 1-3 and the comparative examples is as follows: Figure 1 As shown, the horizontal axis represents biochar materials, and the vertical axis represents the adsorption capacity of biochar materials for phosphate ions.
[0037] Depend on Figure 1 It can be seen that the maximum equilibrium adsorption capacities of SWBC-0.5, SWBC-1, and SWBC-2 for phosphorus are approximately 42.38 mg / g, 77.38 mg / g, and 70.62 mg / g, respectively, all significantly higher than those of PWR and PSS (15.38 mg / g and 30.82 mg / g, respectively). Among them, SWBC-1 showed the best adsorption effect for phosphorus. This indicates that the biochar modified with shrimp shells in this invention can improve the adsorption effect for phosphorus.
[0038] As demonstrated by the above examples, biochar prepared directly from watermelon rind has poor phosphorus adsorption capacity. However, watermelon rind biochar modified with shrimp shells exhibits significantly improved phosphorus adsorption capacity. This invention provides a new approach to the resource utilization of watermelon rind and shrimp shells, and also offers a novel biochar method for phosphorus recovery.
[0039] The present invention has been disclosed above with reference to preferred embodiments, but it is not intended to limit the present invention. All technical solutions obtained by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the present invention.
Claims
1. A method for preparing shrimp shell-modified watermelon rind biochar, characterized in that, include: After dehydrating and drying the watermelon rind, grind it into powder to obtain watermelon rind powder; After drying the shrimp shells, grind them into powder to obtain shrimp shell powder; Watermelon rind powder and shrimp shell powder were mixed and then calcined at high temperature to obtain shrimp shell modified watermelon rind biochar.
2. The method for preparing shrimp shell-modified watermelon rind biochar according to claim 1, characterized in that, The watermelon rind was dried in a forced-air drying oven at 105℃ for 24 hours.
3. The method for preparing shrimp shell-modified watermelon rind biochar according to claim 1, characterized in that, After washing the shrimp shells, place them in a 105℃ drying oven to dry for 2 hours.
4. The method of claim 1, wherein the shrimp shell-modified watermelon rind biochar is prepared by the steps of: Mix watermelon rind powder and shrimp shell powder at a mass ratio of 1:0.5 to 1:
2.
5. The method of claim 1, wherein the shrimp shell-modified watermelon rind biochar is prepared by the steps of: When mixing watermelon rind powder and shrimp shell powder, use a vortex shaker to shake for 1 minute.
6. The method of claim 1, wherein the shrimp shell-modified watermelon rind biochar is prepared by the steps of: The resulting mixture was calcined in a tube furnace at 700°C for 2 h under an argon atmosphere, with a heating rate of 10°C / min.
7. A shrimp shell-modified watermelon rind biochar, characterized by, The biochar was prepared according to any one of claims 1-6 using the method for preparing shrimp shell modified watermelon rind biochar.
8. The application of shrimp shell modified watermelon rind biochar according to claim 7 in the treatment of phosphorus-polluted water bodies.
9. Use according to claim 8, characterized in that, When treating phosphorus-polluted water bodies with a phosphate concentration of 20-200 mg / L (based on phosphorus element), shrimp shell-modified watermelon rind biochar is added to the phosphorus-polluted water body at a dosage of 0.4-1.2 g / L, and the mixture is shaken to complete the adsorption treatment of the phosphorus-polluted water body.
10. Use according to claim 9, characterized in that, The oscillation conditions are: oscillation at a speed of 160~200 rpm and a temperature of 15~35℃ for 2~3 hours.