Preparation method of saponin and polyaspartic acid coupling electrolyte and method for removing heavy metals from soil

Abstract

The application relates to an electrolyte and a method for repairing heavy metals in soil based on a saponin and polyaspartic acid coupling electrolyte. The application is to solve the problems of limited soil quantity for each treatment and high cost in the existing soil heavy metal removal method. The preparation method is as follows: a saponin solution, a polyaspartic acid solution and a sodium chloride solution are mixed according to a volume ratio of 1:1:1, and the saponin and polyaspartic acid coupling electrolyte is obtained. The method for removing heavy metals in soil is as follows: according to the liquid-solid ratio of the electrolyte to the soil of 1.5-2:1, under the conditions of a temperature of 20 DEG C-25 DEG C, an electric current of 10-100 mA / cm, a voltage gradient of 0.4-0.6 v / cm, and a treatment time of 18-24 h. The saponin and polyaspartic acid coupling electrolyte belongs to a green degradable electrolyte, the biodegradation degree reaches 98% on the tenth day after the repair is completed, the secondary pollution to the soil is reduced to the maximum extent, and the electrolyte has the performances of green and high efficiency. The application belongs to the technical field of removing heavy metals in soil.

Description

Technical Field

[0001] This invention relates to an electrolyte and a method for remediating heavy metals in soil. Background Technology

[0002] Currently, the area of ​​soil contaminated with heavy metals is continuously expanding. Under natural conditions, heavy metals leach in ionic form, causing significant environmental hazards. Due to their recalcitrant and highly stable nature, heavy metals cannot be degraded by microorganisms, posing a substantial threat to soil ecosystems. When heavy metals accumulate to a certain level in the soil environment, they can be absorbed by crops, producing a cumulative effect or forming even more toxic compounds. These can lead to skin cancer, adenocarcinoma, neuritis, and other related diseases in humans. Therefore, from the perspective of protecting public health, research on the remediation of heavy metals in soil is of great significance.

[0003] Soil heavy metal removal technologies mainly include electrodynamic removal, chemical methods, and bioleaching. Electrodynamic removal technology offers high removal rates and short processing times, but it consumes a large amount of electricity and has a limited capacity for treating soil volumes per cycle. It is often combined with other technologies to improve removal efficiency, increasing costs and thus limiting its application. Chemical methods utilize various acids or complexing agents to extract heavy metals from the soil into a solution, followed by solid-liquid separation. The remaining heavy metals in the solution are then further processed. Chemical methods are effective in removing heavy metals from soil, but require large amounts of reagents for soil acidification. The resulting acidic solution also needs neutralization, placing high demands on the corrosion resistance of the equipment and resulting in significant reagent and equipment costs. Bioleaching technology utilizes microorganisms to create acidic conditions, releasing heavy metals from the soil into a solution. After mud-water separation, the heavy metals are removed. Commonly used microorganisms in bioleaching include acidophilic thiobacilli such as *Thiobacillus thiooxidans* and *Thiobacillus ferrooxidans*. Bioleaching consumes less acid and results in minimal loss of elements such as nitrogen and phosphorus. However, the pH level drops to around 2 during leaching, which further increases the difficulty and cost of subsequent heavy metal wastewater treatment. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of limited soil volume and high cost in existing methods for removing heavy metals from soil each time, and to provide a method for preparing a saponin and polyaspartic acid coupled electrolyte and a method for remediating heavy metals in soil.

[0005] The preparation method of the saponin-polyaspartic acid coupled electrolyte is as follows:

[0006] 1. Under the condition of 20℃-25℃, add 1.0-2.0g of saponin to 1L of water to prepare a saponin solution with a concentration of 1.0-2.0g / L;

[0007] Prepare a polyaspartic acid solution with a concentration of 1.0-2.0 g / L by adding 1.0-2.0 g of polyaspartic acid to 1 L of water;

[0008] Prepare a 0.01 mol / L sodium chloride solution by adding 1.17 g of sodium chloride to 1 L of water;

[0009] 2. Mix the saponin solution, polyaspartic acid solution and sodium chloride solution in a volume ratio of 1:1:1 to obtain the saponin-polyaspartic acid coupled electrolyte.

[0010] The following methods can be used to remove heavy metals from soil:

[0011] Based on a liquid-to-solid ratio of 1.5-2:1 between the saponin and polyaspartic acid coupled electrolyte and the soil, the soil was treated for 18-24 hours in an electrolyte circulation-enhanced electrodynamic technology remediation device. The conditions were 20℃-25℃, 10-100mA / cm current, and 0.4-0.6v / cm voltage gradient.

[0012] The application of a green electrolyte coupled with saponins and polyaspartic acid in an enhanced electrodynamic remediation device with electrolyte circulation further improves the removal efficiency of heavy metals, making the device more environmentally friendly, efficient, and efficient. This further refines the technical approach of enhancing the electrodynamic remediation device with electrolyte circulation technology, resulting in better treatment effects.

[0013] Saponins and polyaspartic acid undergo complexation reactions with some heavy metal ions, increasing the removal efficiency of heavy metal ions. Simultaneously, the added calcium chloride, saponins, and polyaspartic acid possess excellent conductivity, allowing them to replace traditional electrolytes for conductivity enhancement.

[0014] The saponin-polyaspartic acid coupled electrolyte is a green and biodegradable electrolyte. Ten days after the remediation is completed, the biodegradability reaches 98%, minimizing secondary pollution to the soil and demonstrating green and efficient performance.

[0015] The green electrolyte, which is based on the coupling of saponins and polyaspartic acid, contains saponins and polyaspartic acid. When heavy metal ions come into contact with saponins and polyaspartic acid, they are firmly complexed.

[0016] The present invention provides a method for removing heavy metals from soil that does not require the addition of other electrolytes, and features simple operation, low processing cost, no secondary pollution, and high heavy metal removal efficiency.

[0017] The removal efficiency of heavy metal ions is increased through the complexation reaction of saponins and polyaspartic acid with some heavy metal ions. Simultaneously, the added calcium chloride, saponins, and polyaspartic acid possess good conductivity, allowing them to replace traditional electrolytes for conductivity purposes. Furthermore, this electrolyte is biodegradable and environmentally friendly.

[0018] In the reaction chamber of the electrolyte circulation-enhanced electrodynamic technology device for remediating heavy metal contaminated soil, this green electrolyte comes into contact with the soil contaminated with heavy metals. It undergoes a complexation reaction with the heavy metal ions and simultaneously utilizes the electrolyte's conductivity to enhance the device's effectiveness in remediating heavy metal contaminated soil. This results in superior treatment of heavy metal-contaminated soil, is more environmentally friendly, and has significant practical value.

[0019] Analysis and testing showed that the present invention achieved a removal rate of 77.0%-87.4% for Zn, 66.2%-74.0% for Cu, 85.7%-92.3% for Cr, 56.4%-64.6% for Pb, 84.0%-92.8% for Ni, and 66.5%-73.5% for Mn in sludge. The treated soil met my country's agricultural soil standards. Detailed Implementation

[0020] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0021] Specific Implementation Method 1: The preparation method of the saponin-polyaspartic acid coupled electrolyte in this implementation method is as follows:

[0022] 1. Under the condition of 20℃-25℃, add 1.0-2.0g of saponin to 1L of water to prepare a saponin solution with a concentration of 1.0-2.0g / L;

[0023] Prepare a polyaspartic acid solution with a concentration of 1.0-2.0 g / L by adding 1.0-2.0 g of polyaspartic acid to 1 L of water;

[0024] Prepare a 0.01 mol / L sodium chloride solution by adding 1.17 g of sodium chloride to 1 L of water;

[0025] 2. Mix the saponin solution, polyaspartic acid solution and sodium chloride solution in a volume ratio of 1:1:1 to obtain the saponin-polyaspartic acid coupled electrolyte.

[0026] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the temperature mentioned in step one is 21°C. Everything else is the same as in Specific Implementation Method One.

[0027] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the temperature described in step one is 22°C. Everything else is the same as in Specific Implementation Method One or Two.

[0028] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the temperature described in step one is 23°C. Everything else is the same as in Specific Implementation Methods One to Three.

[0029] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the temperature described in step one is 24°C. Everything else is the same as in Specific Implementation Methods One to Four.

[0030] Specific Implementation Method Six: The method for removing heavy metals from soil in this implementation method is as follows:

[0031] Based on a liquid-to-solid ratio of 1.5-2:1 between the saponin and polyaspartic acid coupled electrolyte and the soil, the soil was treated for 18-24 hours under the conditions of a temperature of 20℃-25℃, a current of 10-100mA / cm, and a voltage gradient of 0.4-0.6V / cm using an electrolyte circulation-enhanced electrodynamic technology for the remediation of heavy metals in soil.

[0032] The electrolyte circulation enhanced electrodynamic technology device for remediating heavy metals in soil described in this embodiment is model SUSEME-SH, manufactured by Zigong Zhenxiong Composite Materials Co., Ltd.

[0033] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Six in that the voltage gradient is 0.5V / cm. Everything else is the same as Specific Implementation Method Six.

[0034] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Six or Seven in that the liquid-to-solid ratio of the saponin-polyaspartic acid coupled electrolyte to the soil is 1.7:1. Everything else is the same as in Specific Implementation Method Six or Seven.

[0035] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods Six to Eight in that the liquid-to-solid ratio of the saponin-polyaspartic acid coupled electrolyte to the soil is 1.8:1. Everything else is the same as in Specific Implementation Methods Six to Eight.

[0036] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods Six to Nine in that the liquid-to-solid ratio of the saponin-polyaspartic acid coupled electrolyte to the soil is 1.9:1. Everything else is the same as in Specific Implementation Methods Six to Nine.

[0037] The following experiments were used to verify the effectiveness of the invention:

[0038] Experiment 1:

[0039] The preparation method of the saponin-polyaspartic acid coupled electrolyte is as follows:

[0040] 1. At a temperature of 25℃, add 1.0g of saponin to 1L of water to prepare a saponin solution with a concentration of 1.0g / L;

[0041] Prepare a 1.5g / L polyaspartic acid solution by adding 1.5g of polyaspartic acid to 1L of water;

[0042] Prepare a 0.01 mol / L sodium chloride solution by adding 1.17 g of sodium chloride to 1 L of water;

[0043] 2. Mix the saponin solution, polyaspartic acid solution and sodium chloride solution in a volume ratio of 1:1:1 to obtain the saponin-polyaspartic acid coupled electrolyte.

[0044] The following methods can be used to remove heavy metals from soil:

[0045] Based on a liquid-to-solid ratio of 2:1 between the saponin and polyaspartic acid coupled electrolyte and the soil, the soil was treated for 24 hours in an electrolyte circulation-enhanced electrodynamic technology remediation device for heavy metals. The conditions were 25℃, 50mA / cm current, and 0.5V / cm voltage gradient.

[0046] Analysis and testing showed that this experiment achieved a removal rate of 77.0% for Zn, 66.2% for Cu, 85.7% for Cr, 56.4% for Pb, 84.0% for Ni, and 66.5% for Mn from the sludge. The treated soil met my country's agricultural soil standards.

[0047] Experiment 2:

[0048] The preparation method of the saponin-polyaspartic acid coupled electrolyte is as follows:

[0049] 1. At a temperature of 25℃, add 1.5g of saponin to 1L of water to prepare a saponin solution with a concentration of 1.5g / L;

[0050] Prepare a 2.0 g / L polyaspartic acid solution by adding 2.0 g of polyaspartic acid to 1 L of water;

[0051] Prepare a 0.01 mol / L sodium chloride solution by adding 1.17 g of sodium chloride to 1 L of water;

[0052] 2. Mix the saponin solution, polyaspartic acid solution and sodium chloride solution in a volume ratio of 1:1:1 to obtain the saponin-polyaspartic acid coupled electrolyte.

[0053] The following methods can be used to remove heavy metals from soil:

[0054] Based on a liquid-to-solid ratio of 2:1 between the saponin and polyaspartic acid coupled electrolyte and the soil, the soil was treated for 24 hours in an electrolyte circulation-enhanced electrodynamic technology remediation device for heavy metals. The conditions were 25℃, 50mA / cm current, and 0.5V / cm voltage gradient.

[0055] Analysis and testing showed that this experiment achieved a removal rate of 82.2% for Zn, 70.6% for Cu, 89.0% for Cr, 60.0% for Pb, 88.4% for Ni, and 70.0% for Mn from the sludge. The treated soil met my country's agricultural soil standards.

[0056] Experiment 3:

[0057] The preparation method of the saponin-polyaspartic acid coupled electrolyte is as follows:

[0058] 1. At a temperature of 25℃, add 2.0g of saponin to 1L of water to prepare a saponin solution with a concentration of 2.0g / L;

[0059] Prepare a 2.0 g / L polyaspartic acid solution by adding 2.0 g of polyaspartic acid to 1 L of water;

[0060] Prepare a 0.01 mol / L sodium chloride solution by adding 1.17 g of sodium chloride to 1 L of water;

[0061] 2. Mix the saponin solution, polyaspartic acid solution and sodium chloride solution in a volume ratio of 1:1:1 to obtain the saponin-polyaspartic acid coupled electrolyte.

[0062] The following methods can be used to remove heavy metals from soil:

[0063] Based on a liquid-to-solid ratio of 2:1 between the saponin and polyaspartic acid coupled electrolyte and the soil, the soil was treated for 24 hours in an electrolyte circulation-enhanced electrodynamic technology remediation device for heavy metals. The conditions were 25℃, 50mA / cm current, and 0.5V / cm voltage gradient.

[0064] Analysis and testing showed that this experiment achieved a removal rate of 87.4% for Zn, 74.0% for Cu, 92.3% for Cr, 64.6% for Pb, 92.8% for Ni, and 73.5% for Mn from the sludge. The treated soil met my country's agricultural soil standards.

Claims

1. A method for preparing a saponin-polyaspartic acid coupled electrolyte, characterized in that... The preparation method of the saponin-polyaspartic acid coupled electrolyte is as follows:

1. Under the condition of 20℃-25℃, add 1.0-2.0g of saponin to 1L of water to prepare a saponin solution with a concentration of 1.0-2.0g / L; Prepare a polyaspartic acid solution with a concentration of 1.0-2.0 g / L by adding 1.0-2.0 g of polyaspartic acid to 1 L of water; Prepare a 0.01 mol / L sodium chloride solution by adding 1.17 g of sodium chloride to 1 L of water; 2. Mix the saponin solution, polyaspartic acid solution and sodium chloride solution in a volume ratio of 1:1:1 to obtain the saponin-polyaspartic acid coupled electrolyte.

2. The preparation method of the saponin and polyaspartic acid coupled electrolyte according to claim 1, characterized in that... The temperature mentioned in step one is 21℃.

3. The preparation method of the electrolyte based on the coupling of saponin and polyaspartic acid according to claim 1, characterized in that... The temperature mentioned in step one is 22℃.

4. The preparation method of the saponin and polyaspartic acid coupled electrolyte according to claim 1, characterized in that... The temperature mentioned in step one is 23℃.

5. The preparation method of the saponin and polyaspartic acid coupled electrolyte according to claim 1, characterized in that... The temperature mentioned in step one is 24℃.

6. A method for removing heavy metals from soil, characterized in that... The method for removing heavy metals from soil is as follows: The saponin and polyaspartic acid coupled electrolyte prepared according to the preparation method of claim 1, with a liquid-to-solid ratio of 1.5-2:1 to soil, was treated for 18-24 hours in an electrolyte circulation enhanced electrodynamic technology remediation device for heavy metals in soil under the conditions of a temperature of 20℃-25℃, a current of 10-100mA / cm, and a voltage gradient of 0.4-0.6V / cm.

7. The method for removing heavy metals from soil according to claim 6, characterized in that... The voltage gradient is 0.5V / cm.

8. The method for removing heavy metals from soil according to claim 6, characterized in that... The liquid-to-solid ratio of the electrolyte based on the coupling of saponins and polyaspartic acid to the soil is 1.7:

1.

9. The method for removing heavy metals from soil according to claim 6, characterized in that... The liquid-to-solid ratio of the electrolyte based on the coupling of saponins and polyaspartic acid to the soil is 1.8:

1.

10. The method for removing heavy metals from soil according to claim 6, characterized in that... The liquid-to-solid ratio of the electrolyte based on the coupling of saponins and polyaspartic acid to the soil is 1.9:1.