Multi-enzyme nano-repairing agent, preparation method and application thereof

Abstract

The application belongs to the technical field of soil remediation, and particularly relates to a multi-enzyme nano remediation agent and a preparation method and application thereof. The application provides a multi-enzyme nano remediation agent, which comprises multi-enzyme nano remediation agent A and multi-enzyme nano remediation agent B. The multi-enzyme nano remediation agent A comprises sugarcane molasses, chitosan, wheat bran, oxidase, dry yeast, protease, cellulase, castor oil and water. The multi-enzyme nano remediation agent B comprises peanut shell powder, monoammonium phosphate, ferrous sulfate, denatured shell powder, nano silicon dioxide and vegetable oil. The multi-enzyme nano remediation agent A and the multi-enzyme nano remediation agent B are used in combination to improve the degradation rate of indigenous microorganisms in decomposing petroleum hydrocarbons, and shorten the bioremediation cycle of petroleum hydrocarbon contaminated soil.

Description

Technical Field

[0001] This invention belongs to the field of soil remediation technology, specifically relating to a multi-enzyme nano-remediation agent, its preparation method, and its application. Background Technology

[0002] my country is one of the world's major oil-producing countries, with more than 400 oil fields under exploration and development, but it lacks oil pollution control and corresponding remediation technologies.

[0003] Current technologies for remediating petroleum hydrocarbon-contaminated soil can be broadly categorized into three types: physical remediation, chemical remediation, and biological remediation.

[0004] Physical remediation methods include heat treatment, soil replacement, isolation, and air stripping. The essence of physical remediation of petroleum hydrocarbon pollution is to transfer pollutants, but it does not fundamentally solve the pollution problem, so it is only used in specified situations.

[0005] Chemical remediation methods mainly include extraction, chemical leaching, and chemical oxidation. These methods all involve adding agents to the soil, which, while converting petroleum hydrocarbons, also introduces secondary pollutants, making soil pollutants more diverse and complex, requiring further remediation work.

[0006] Bioremediation refers to the process of adding nutrients and petroleum hydrocarbon-degrading bacteria to contaminated soil to absorb and degrade petroleum hydrocarbons, converting them into carbon dioxide and water. Because bioremediation does not involve chemical additives, and the final products of petroleum hydrocarbon conversion are carbon dioxide and water, it is considered the most promising method for remediating petroleum hydrocarbon pollution. However, current bioremediation methods for petroleum hydrocarbon pollution suffer from long cycles and low remediation efficiency. Summary of the Invention

[0007] The purpose of this invention is to provide a multi-enzyme nano-remediation agent that can shorten the bioremediation cycle of petroleum hydrocarbon-contaminated soil and improve the degradation rate of petroleum hydrocarbons.

[0008] To address the above problems, the present invention provides the following technical solution:

[0009] This invention provides a multi-enzyme nano-repair agent, comprising multi-enzyme nano-repair agent A and multi-enzyme nano-repair agent B;

[0010] The multi-enzyme nano-repair agent A includes sugarcane molasses, chitosan, wheat bran, oxidase, dried yeast, protease, cellulase, castor oil, and water;

[0011] The multi-enzyme nano-repair agent B includes peanut shell powder, monoammonium phosphate, ferrous sulfate, modified shell powder, nano-silica, and vegetable oil;

[0012] The modified shell powder is obtained by grinding fresh shells after removing impurities and purifying them.

[0013] Preferably, by mass percentage, the multi-enzyme nano-repair agent A comprises 10%–20% sugarcane molasses, 10%–20% chitosan, 1%–10% wheat bran, 1%–5% oxidase, 1%–5% dried yeast, 0.5%–3% protease, 0.5%–2% cellulase, 1%–10% castor oil, and 40%–60% water;

[0014] By weight percentage, the multi-enzyme nano-repair agent B comprises 20%–30% peanut shell powder, 30%–50% monoammonium phosphate, 1%–10% ferrous sulfate, 20%–40% denatured shell powder, 0.5%–1% nano-silica, and 1%–5% vegetable oil.

[0015] Preferably, the cellulase activity is greater than 60,000 U / mL.

[0016] This invention provides a method for preparing the multi-enzyme nano-repair agent described above, comprising the following steps:

[0017] Water, sugarcane molasses, chitosan, wheat bran, oxidase, dry yeast, protease and cellulase were mixed and kept warm. Castor oil was then added to obtain multi-enzyme nano-repair agent A.

[0018] Peanut shell powder, monoammonium phosphate, ferrous sulfate, modified shell powder, and nano-silica were mixed in a second mixture. Vegetable oil was sprayed in during the second mixing process to obtain multi-enzyme nano-repair agent B.

[0019] Preferably, the insulation temperature is 26–35°C, and the insulation time is 2–4 days.

[0020] Preferably, the second mixing is a stirring mixing, wherein the stirring speed is 15-25 r / min and the stirring time is 3-5 min.

[0021] This invention provides the application of the multi-enzyme nano-remediation agent described in the above technical solution or the multi-enzyme nano-remediation agent prepared by the preparation method described in the above technical solution in the remediation of petroleum hydrocarbon contaminated soil.

[0022] Preferably, the application includes: adding multi-enzyme nano-remediation agent B to petroleum hydrocarbon-contaminated soil, followed by adding multi-enzyme nano-remediation agent A for composting and curing, curing for 28-35 days; if the degradation rate of petroleum hydrocarbons in the soil is less than 50%, then adding multi-enzyme nano-remediation agent B a second time; after adding multi-enzyme nano-remediation agent, adjusting the saturated water holding capacity of the petroleum hydrocarbon-contaminated soil to 55%-65%, and the pH value of the petroleum hydrocarbon-contaminated soil to 6-8.

[0023] Preferably, the repair temperature is not lower than 15°C, and the pile is turned over 1 to 2 times per week during the repair process.

[0024] Preferably, when the mass content of petroleum hydrocarbons in the contaminated soil does not exceed 6%, the amount of multi-enzyme nano-remediation agent A added is 0.5% to 2% of the mass of the petroleum hydrocarbon-contaminated soil, and the amount of multi-enzyme nano-remediation agent B added is 0.5% to 3% of the mass of the petroleum hydrocarbon-contaminated soil.

[0025] The beneficial effects of this invention are as follows: The purpose of this invention is to provide a multi-enzyme nano-repair agent, comprising multi-enzyme nano-repair agent A and multi-enzyme nano-repair agent B; the multi-enzyme nano-repair agent A comprises cane molasses, chitosan, wheat bran, oxidase, dried yeast, protease, cellulase, castor oil and water; the multi-enzyme nano-repair agent B comprises peanut shell powder, monoammonium phosphate, ferrous sulfate, modified shell powder, nano silica and vegetable oil; the modified shell powder is a powder obtained by grinding fresh shells after removing impurities and purifying them. Based on the principles of bioremediation, this invention's multi-enzyme nano-remediation agent utilizes multi-enzyme remediation technology without the addition of exogenous bacteria. It leverages the catalytic action of a complex of enzymes (oxidase, dry yeast, protease, and cellulase). In the initial stages of soil remediation, high concentrations of extracellular enzymes, combined with suitable nutrients, promote the rapid growth and reproduction of indigenous microorganisms. Under the influence of petroleum hydrocarbon pollutants, through microbial gene mutation and adaptive selectivity, indigenous microorganisms that degrade petroleum hydrocarbons form a dominant population. These microorganisms use petroleum hydrocarbons as their sole carbon source during growth and reproduction, rapidly consuming them through metabolism and co-metabolism. This rapidly removes petroleum hydrocarbon pollutants without damaging soil properties, thus remediating petroleum hydrocarbon-contaminated soil. Specifically, multi-enzyme nano-remediation agent A provides the indigenous microorganisms in petroleum hydrocarbon-contaminated soil with complex enzymes and nutrients, promoting a rapid increase in their numbers. Sugarcane molasses and chitosan are carbohydrate nutrients, wheat bran is a fibrous nutrient, castor oil is an emulsifier and a fat nutrient, while water can activate enzymes. Oxidase, dried yeast, protease, and cellulase form an enzyme complex that acts as coenzymes for the growth and reproduction of indigenous microorganisms. During the metabolism of indigenous microorganisms, they lower the activation energy of chemical reactions, thus playing a catalytic role and promoting the growth and reproduction of indigenous microorganisms in petroleum hydrocarbon-contaminated soil. Furthermore, multi-enzyme nano-remediation agent B provides nutrients, catalysts, and co-metabolic substrates for the growth and reproduction of indigenous microorganisms that degrade petroleum hydrocarbon pollution; peanut shell powder provides fiber support and co-metabolic substrates for the soil; monoammonium phosphate provides nitrogen and phosphorus nutrients needed for microbial growth and reproduction; ferrous sulfate provides sulfur ions needed for microbial reproduction; denatured shell powder provides calcium, magnesium ions, and chitin needed for microbial reproduction and has the function of adsorbing heavy metal toxins; nano-silica acts as a catalyst; and vegetable oil plays a dust-removing role during raw material mixing. Therefore, this invention utilizes the combined action of multi-enzyme nano-remediation agent A and multi-enzyme nano-remediation agent B to improve the degradation rate of petroleum hydrocarbons by indigenous microorganisms, thereby shortening the bioremediation cycle of petroleum hydrocarbon-contaminated soil. The multi-enzyme nano-remediation agent of this invention can remediate various types of petroleum hydrocarbon pollution rapidly; when the mass percentage of petroleum hydrocarbons in the contaminated soil is no more than 6%, it can reduce the mass percentage of petroleum hydrocarbons in the contaminated soil to below 0.3% within 40–70 days. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0027] Figure 1 The specific application process for multi-enzyme repair agents;

[0028] Figure 2 The total petroleum hydrocarbon content detection data during the maintenance process of the multi-enzyme repair agent in Example 1;

[0029] Figure 3 The total petroleum hydrocarbon content detection data during the maintenance process of the multi-enzyme repair agent in Example 2;

[0030] Figure 4 The total petroleum hydrocarbon content detection data during the maintenance process of the multi-enzyme repair agent in Example 3;

[0031] Figure 5 This is the total petroleum hydrocarbon content detection data during the maintenance process of the multi-enzyme repair agent in Comparative Example 1;

[0032] Figure 6 The total petroleum hydrocarbon content detection data is for Comparative Example 2 during the maintenance process with the multi-enzyme repair agent;

[0033] Figure 7 The total petroleum hydrocarbon content detection data is for Comparative Example 3 during the maintenance process of the multi-enzyme repair agent;

[0034] Figure 8 The total petroleum hydrocarbon content detection data is for Comparative Example 4 during the maintenance process with the multi-enzyme repair agent;

[0035] Figure 9 The total petroleum hydrocarbon content detection data is for Comparative Example 5 during the maintenance process with the multi-enzyme repair agent.

[0036] Figure 10 Example 4, number 1 ～ The results of the petroleum hydrocarbon content measurement before and after the restoration of No. 4. Detailed Implementation

[0037] This invention provides a multi-enzyme nano-repair agent, comprising multi-enzyme nano-repair agent A and multi-enzyme nano-repair agent B;

[0038] The multi-enzyme nano-repair agent A includes sugarcane molasses, chitosan, wheat bran, oxidase, dried yeast, protease, cellulase, castor oil, and water;

[0039] The multi-enzyme nano-repair agent B includes peanut shell powder, monoammonium phosphate, ferrous sulfate, modified shell powder, nano-silica, and vegetable oil;

[0040] The modified shell powder is obtained by grinding fresh shells after they have been cleaned and purified. The modified shell powder of this invention is essentially produced by grinding the purified shells using a ball mill for more than 5 hours. Through grinding, the aragonite-type calcium carbonate in the shell powder is transformed into calcite-type calcium carbonate, thereby weakening the bonding force of the calcium carbonate groups and facilitating the release of calcium ions.

[0041] The multi-enzyme nano-repair agent B described in this invention is a powder mixture; the multi-enzyme nano-repair agent A is a liquid mixture.

[0042] When petroleum hydrocarbons enter the soil, the number of indigenous microorganisms in the soil decreases sharply, resulting in slow natural degradation of petroleum hydrocarbons. Furthermore, existing bioremediation agents for petroleum-contaminated soil primarily consist of nitrogen, phosphorus, and potassium, nutrients required by petroleum hydrocarbon-degrading bacteria, leading to unsatisfactory remediation results. This invention addresses this problem with a multi-enzyme nano-remediation agent. This agent utilizes multi-enzyme remediation technology to increase the synthesis rate of microorganisms under the action of enzyme components. When added to petroleum hydrocarbon-contaminated soil, it activates and enriches indigenous microorganisms. These activated microorganisms, through gene mutation and natural selection, alter their selectivity for petroleum hydrocarbons, gradually enriching indigenous microbial species adapted to the new substrate. Through the metabolism and co-metabolism of the microbial community, the corresponding petroleum hydrocarbon pollutants are degraded, effectively shortening the remediation cycle of petroleum hydrocarbon-contaminated soil and increasing the degradation rate. The co-metabolism mentioned in this invention refers to the process where, for certain toxic substances that cannot be directly degraded by microorganisms, the addition of readily degradable substances, such as glucose, can promote or initiate the degradation of these recalcitrant substances and introduce them into the cycle.

[0043] This invention's multi-enzyme nano-remediation agent can rapidly repair various petroleum hydrocarbons, including n-alkanes, branched alkanes, cycloalkanes, and aromatics, as well as small amounts of other organic compounds such as benzenes and phenols. It quickly restores the basic properties of the soil, is low-cost, and complies with national environmental protection policies. The multi-enzyme nano-remediation agent of this invention rapidly removes petroleum hydrocarbon pollutants without damaging soil properties, enabling rapid remediation of petroleum hydrocarbon-contaminated soil.

[0044] Unless otherwise specified, the present invention does not have special requirements for the source of the components, and conventional commercially available products can be used.

[0045] The multi-enzyme nano-repair agent A provided by the present invention preferably comprises 10% to 20% sugarcane molasses, more preferably 11% to 18%, and even more preferably 15% by weight percentage. In the present invention, the sugarcane molasses is a sugar nutrient that promotes the growth of indigenous microorganisms in petroleum hydrocarbon-contaminated soil.

[0046] The multi-enzyme nano-repair agent A provided by this invention preferably comprises 10% to 20% chitosan by weight percentage, more preferably 11% to 15%, and even more preferably 13%. In this invention, the chitosan is a carbohydrate nutrient that promotes the growth of indigenous microorganisms in petroleum hydrocarbon-contaminated soil. The chitosan particle size of this invention is required to be above 1200 mesh.

[0047] The multi-enzyme nano-repair agent A provided by this invention preferably comprises 1% to 10% wheat bran, more preferably 4% to 8%, and even more preferably 5% by weight percentage. In this invention, the wheat bran is a fibrous nutrient that promotes the growth of indigenous microorganisms in petroleum hydrocarbon-contaminated soil. The particle size of the wheat bran in this invention is preferably 30 to 40 mesh, more preferably 34 to 36 mesh, and even more preferably 35 mesh. The selection of the wheat bran particle size in this invention is to maintain a suitable proportion of fiber, starch, protein, and other components in the wheat bran, while also providing support and aeration when added to petroleum-contaminated soil, thereby better promoting the growth and reproduction of indigenous microorganisms in the soil.

[0048] The multi-enzyme nano-repair agent A provided by the present invention preferably comprises 1% to 5% oxidase by weight percentage, more preferably 1.5% to 3%, and even more preferably 2.5%. The present invention does not impose any particular limitation on the enzyme activity of the oxidase.

[0049] The multi-enzyme nano-repair agent A provided by the present invention preferably comprises 0.2% to 2% protease by weight percentage, more preferably 0.2% to 1%, and even more preferably 0.5%. The protease described in the present invention preferably includes papain. The present invention does not specifically limit the enzymatic activity of the protease.

[0050] The multi-enzyme nano-repair agent A provided by the present invention preferably comprises 0.5% to 2% cellulase, more preferably 0.7% to 1.5%, and even more preferably 1% by mass percentage. The cellulase activity of the present invention is preferably greater than 60,000 units.

[0051] The multi-enzyme nano-repair agent A provided by this invention preferably comprises 1% to 5% dried yeast, more preferably 1.5% to 3%, and even more preferably 2% by mass percentage. The dried yeast mentioned in this invention is also known as yeast, preferably brewer's yeast or grape juice yeast. The multi-enzyme nano-repair agent A of this invention is a liquid multi-enzyme substance, i.e., a complex enzyme. The oxidase, dried yeast, protease, and cellulase in the multi-enzyme nano-repair agent A of this invention together form an enzyme complex, playing an enzymatic catalytic role. After activation, various enzymes form tiny aggregates similar to nanomembranes, creating a high-concentration extracellular enzyme environment. This environment serves as a coenzyme for the reproduction and growth of microorganisms in the soil, accelerating the division, reproduction, metabolism, and co-metabolism of indigenous petroleum hydrocarbon-degrading microorganisms, and increasing the rate of microbial synthesis.

[0052] The multi-enzyme nano-repair agent A provided by the present invention preferably comprises 1% to 10% castor oil, more preferably 2% to 8%, and even more preferably 6% by weight. The castor oil described in the present invention is a fatty nutrient that promotes the growth and reproduction of indigenous microorganisms in petroleum hydrocarbon-contaminated soil.

[0053] The multi-enzyme nano-repair agent A provided by this invention preferably comprises 40-60% water by weight, more preferably 50%-58%, and even more preferably 55%. The water added in this invention is mainly to promote the activation of oxidases, dried yeast, proteases, and cellulases. This invention does not have a particular limitation on the source of water, but purified water is more preferred.

[0054] The multi-enzyme nano-remediation agent B provided by this invention preferably comprises 20%–30% peanut shell powder, more preferably 22%–28%, and even more preferably 24% by weight percentage. The peanut shell powder of this invention preferably has a particle size of 25–40 mesh, and even more preferably 30 mesh. The peanut shell powder of this invention primarily provides fibrous support for petroleum-contaminated soil, better promoting the support and aeration of the soil. Furthermore, peanut shell powder within this particle size range is easily degraded in the later stages of soil remediation and will not damage the properties of the petroleum-contaminated soil.

[0055] The multi-enzyme nano-repair agent B provided by the present invention preferably comprises 30% to 50% monoammonium phosphate, more preferably 35% to 48%, and even more preferably 40% by weight percentage. The monoammonium phosphate of the present invention can provide nitrogen and phosphorus nutrients for the growth and reproduction of indigenous microorganisms.

[0056] The multi-enzyme nano-repair agent B provided by this invention preferably comprises 1% to 10% ferrous sulfate, more preferably 2% to 8%, and even more preferably 7% by weight percentage. The ferrous sulfate described in this invention is preferably anhydrous ferrous sulfate. The ferrous sulfate of this invention provides sulfate ions required for the growth and reproduction of indigenous microorganisms.

[0057] The multi-enzyme nano-repair agent B provided by the present invention preferably comprises 20% to 40% denatured shell powder, more preferably 22% to 35%, and even more preferably 25% by weight percentage.

[0058] The modified shell powder of this invention is preferably obtained by grinding fresh shells after purification and impurity removal. The purification temperature is preferably 110℃, the purification time is preferably 10 minutes, and the particle size of the modified shell powder is preferably 200-500 mesh, more preferably 300-350 mesh. The purification is preferably completed in a dryer, and the grinding is preferably completed in a grinding mill, with a grinding time not less than 15 minutes. The selection of the purification temperature and time for the modified shell powder of this invention is mainly to eliminate impurities and parasites on the shell surface, retain the calcium and magnesium components of the shell itself, and provide calcium ions, magnesium ions, and chitin for the growth and reproduction of indigenous microorganisms.

[0059] The multi-enzyme nano-repair agent B provided by the present invention preferably comprises 0.5% to 1% nano-silica, more preferably 0.5% to 0.8%, and even more preferably 0.6% by mass percentage. The nano-silica of the present invention is used as a catalyst to catalyze the degradation of petroleum hydrocarbons into carbon dioxide and water.

[0060] The multi-enzyme nano-repair agent B provided by this invention preferably comprises 1% to 5% vegetable oil, more preferably 2% to 4.5%, and even more preferably 3.4% by mass percentage. The vegetable oil used in this invention can be a conventional product, preferably including one or more of soybean oil, peanut oil, sunflower seed oil, or rapeseed oil. The vegetable oil used in this invention plays a role in dust removal and modification when peanut shell powder, monoammonium phosphate, ferrous sulfate, modified shell powder, and nano-silica are mixed. The vegetable oil used in this invention uniformly aggregates the various raw materials during mixing, acting as a binder, enhancing the bonds between the raw materials, forming tiny functional compounds, and improving the utilization rate and efficiency of various elements.

[0061] Existing remediation agents for petroleum-contaminated soil contain nitrogen, phosphorus, and potassium nutrients that promote the growth of indigenous microorganisms. The components used in the multi-enzyme nano-remediation agent A of this invention have not been reported. The multi-enzyme remediation agent of this invention can rapidly consume petroleum hydrocarbons in contaminated soil, quickly removing petroleum hydrocarbon pollutants without damaging soil properties, thus enabling rapid remediation of petroleum hydrocarbon-contaminated soil.

[0062] This invention also provides a method for preparing the multi-enzyme nano-repair agent described in the above technical solution, comprising the following steps:

[0063] Water, sugarcane molasses, chitosan, wheat bran, oxidase, dry yeast, protease and cellulase were mixed and kept warm. Castor oil was then added to obtain multi-enzyme nano-repair agent A.

[0064] Peanut shell powder, monoammonium phosphate, ferrous sulfate, modified shell powder, and nano-silica were mixed in a second mixture. Vegetable oil was sprayed in during the second mixing process to obtain multi-enzyme nano-repair agent B.

[0065] This invention involves mixing water, sugarcane molasses, chitosan, wheat bran, oxidase, dry yeast, protease, and cellulase, then keeping the mixture warm, and finally adding castor oil to obtain multi-enzyme nano-repair agent A. More preferably, sugarcane molasses is first dissolved in water, stirred evenly, and then chitosan, wheat bran, oxidase, dry yeast, protease, and cellulase are added sequentially and mixed. After keeping the mixture warm and still for 2-4 days, castor oil is added to obtain multi-enzyme nano-repair agent A.

[0066] In the first mixing of this invention, there is no particular limitation on the order of adding water, cane molasses, chitosan, wheat bran, oxidase, dry yeast, protease, and cellulase; a conventional addition order is acceptable. This invention first mixes water, cane molasses, chitosan, wheat bran, oxidase, dry yeast, protease, and cellulase of the multi-enzyme nano-repair agent A. More preferably, the cane molasses is first dissolved in water, and then chitosan, wheat bran, oxidase, dry yeast, protease, and cellulase are added sequentially. The first mixing of this invention is preferably carried out under stirring conditions. This invention does not have particular limitations on the stirring speed and time, as long as all raw material components are stirred evenly. This invention does not have particular limitations on the stirring container, but it is preferably carried out in a temperature-adjustable container. The temperature for heat preservation in this invention is preferably 26–35°C, more preferably 28–30°C, and the heat preservation time is preferably 2–4 days, more preferably 3 days. The purpose of heat preservation in this invention is to increase the activity of various enzymes in the multi-enzyme nano-repair agent, so that it can quickly take effect after being applied to petroleum hydrocarbon-contaminated soil.

[0067] After heat preservation, a mixture of water, sugarcane molasses, chitosan, wheat bran, oxidase, dry yeast, protease, and cellulase is obtained. Preferably, castor oil is added to the mixture, and the mixture is stirred again until homogeneous. After cooling to room temperature, the multi-enzyme nano-repair agent A is obtained. This invention does not have specific limitations on the stirring speed and time, as long as all raw material components are stirred evenly. The multi-enzyme nano-repair agent A of this invention is preferably a liquid multi-enzyme repair agent.

[0068] This invention involves a second mixing of peanut shell powder, monoammonium phosphate, ferrous sulfate, modified shell powder, and nano-silica. Vegetable oil is then sprayed into the mixture during this second mixing process to obtain a multi-enzyme nano-repair agent B. Preferably, the order in which the peanut shell powder, monoammonium phosphate, ferrous sulfate, modified shell powder, and nano-silica are added during the second mixing is not particularly limited; a conventional order is acceptable. More preferably, the peanut shell powder, monoammonium phosphate, ferrous sulfate, modified shell powder, and nano-silica are added sequentially. The second mixing process is preferably performed by stirring. The stirring speed is preferably 15–25 r / min, more preferably 20 r / min. The stirring time is preferably 3–5 min, more preferably 4 min. The second mixing process is preferably completed in a mixer.

[0069] This invention provides the application of the multi-enzyme nano-remediation agent described in the above technical solution or the multi-enzyme nano-remediation agent prepared by the preparation method described in the above technical solution in the remediation of petroleum hydrocarbon contaminated soil.

[0070] In this invention, the preferred application includes: adding multi-enzyme nano-remediation agent B to petroleum hydrocarbon-contaminated soil, followed by adding multi-enzyme nano-remediation agent A for composting and curing for 28-35 days; if the degradation rate of petroleum hydrocarbons in the soil is less than 50%, then adding multi-enzyme nano-remediation agent B a second time; the saturated water holding capacity of the petroleum hydrocarbon-contaminated soil after adding the multi-enzyme nano-remediation agent is preferably adjusted to 55%-65%, more preferably 60%; the pH value of the petroleum hydrocarbon-contaminated soil is 6-8.

[0071] The invention first adds multi-enzyme nano-remediation agent B to the petroleum hydrocarbon-contaminated soil so that it can be easily mixed evenly when the contaminated soil is in powder form (with low moisture content). It is necessary to add multi-enzyme nano-remediation agent B first.

[0072] More preferably, this invention involves adding multi-enzyme nano-remediation agent B to petroleum hydrocarbon-contaminated soil, mixing them evenly, then adding multi-enzyme nano-remediation agent A, mixing them evenly, and then composting and curing the soil.

[0073] Before adding the multi-enzyme nano-remediation agent, this invention first treats the petroleum hydrocarbon-contaminated soil. The treatment method preferably involves sun-drying the petroleum hydrocarbon-contaminated soil, which has a high moisture content and is in a muddy state. The sun-drying is preferably carried out until the moisture content of the petroleum hydrocarbon-contaminated soil is less than 15%, sufficient for mechanical homogenization. The homogenization is preferably achieved by mechanically breaking up any clumps in the sun-dried petroleum hydrocarbon-contaminated soil. Preferably, the particle size of the homogenized petroleum hydrocarbon-contaminated soil does not exceed 2 cm. This invention does not have specific limitations on the homogenization parameters; conventional parameters are acceptable. The purpose of homogenization is to remove stones and plant debris from the petroleum hydrocarbon-contaminated soil and eliminate large soil particles. The homogenization is preferably carried out using crushing and screening equipment.

[0074] After homogenization, the pH value of the homogenized petroleum hydrocarbon-contaminated soil is preferably measured. The pH value of the petroleum hydrocarbon-contaminated soil is 6-8, more preferably 7. When the pH value of the petroleum hydrocarbon-contaminated soil is less than 6, the pH value is preferably adjusted using lime. When the pH value of the petroleum hydrocarbon-contaminated soil is greater than 8, the pH value is preferably adjusted using citric acid.

[0075] After adjusting the pH value of the petroleum hydrocarbon-contaminated soil, this invention preferably detects the content and types of organic pollutants in the petroleum hydrocarbon-contaminated soil to determine the petroleum hydrocarbon content and the dosage of multi-enzyme nano-remediation agent A and multi-enzyme nano-remediation agent B. When the petroleum hydrocarbon content in the petroleum hydrocarbon-contaminated soil is no more than 6%, the dosage of multi-enzyme nano-remediation agent A is 0.5% to 2% of the mass of the petroleum hydrocarbon-contaminated soil, and the dosage of multi-enzyme nano-remediation agent B is 0.5% to 3% of the mass of the petroleum hydrocarbon-contaminated soil.

[0076] Specifically: when the petroleum hydrocarbon content in the petroleum hydrocarbon-contaminated soil is less than 1%, the preferred addition amount of multi-enzyme nano-remediation agent A is 0.5% to 1% of the mass of the petroleum hydrocarbon-contaminated soil, and the preferred addition amount of multi-enzyme nano-remediation agent B is 0.5% to 1% of the mass of the petroleum hydrocarbon-contaminated soil.

[0077] When the petroleum hydrocarbon content in the petroleum hydrocarbon-contaminated soil is 1% to 2%, the preferred addition amount of multi-enzyme nano-remediation agent A is 0.5% to 1% of the mass of the petroleum hydrocarbon-contaminated soil, and the preferred addition amount of multi-enzyme nano-remediation agent B is 1% to 1.5% of the mass of the petroleum hydrocarbon-contaminated soil.

[0078] When the petroleum hydrocarbon content in the petroleum hydrocarbon-contaminated soil is 2% to 4%, the preferred addition amount of multi-enzyme nano-remediation agent A is 1% to 2% of the mass of the petroleum hydrocarbon-contaminated soil, and the preferred addition amount of multi-enzyme nano-remediation agent B is 1.5% to 2% of the mass of the petroleum hydrocarbon-contaminated soil.

[0079] When the petroleum hydrocarbon content in the petroleum hydrocarbon-contaminated soil is 4% to 6%, the preferred addition amount of multi-enzyme nano-remediation agent A is 1% to 2% of the mass of the petroleum hydrocarbon-contaminated soil, more preferably 1.8%; the preferred addition amount of multi-enzyme nano-remediation agent B is 1.5% to 3% of the mass of the petroleum hydrocarbon-contaminated soil, more preferably 2%.

[0080] Regardless of the mass percentage of petroleum hydrocarbons in the polluted soil, as long as the mass percentage of polycyclic aromatic hydrocarbons in the polluted soil exceeds 50% of the petroleum hydrocarbon pollutants, the dosage of multi-enzyme nano-remediation agent A should be greater than 1% of the soil mass. The dosage of multi-enzyme nano-remediation agent B should be consistent with the parameter range of the dosage of multi-enzyme nano-remediation agent B selected above based on the petroleum hydrocarbon content.

[0081] The multi-enzyme nano-repair agent described in this invention can shorten the repair time by 6 to 8 days when the amount added is increased. However, the amount added should not exceed twice the amount of the original multi-enzyme nano-repair agent. Adding more than twice the amount of the original multi-enzyme nano-repair agent will disrupt the nutrient balance required by microorganisms in petroleum hydrocarbon-contaminated soil, and the repair effect will be much lower than expected.

[0082] This invention preferably involves adding multi-enzyme nano-remediation agent B to petroleum hydrocarbon-contaminated soil after pH adjustment, followed by adding multi-enzyme nano-remediation agent A for composting and curing. More preferably, it involves adding multi-enzyme nano-remediation agent B to the petroleum hydrocarbon-contaminated soil, mixing thoroughly, then adding multi-enzyme nano-remediation agent A, mixing thoroughly, and finally composting and curing. Before adding multi-enzyme nano-remediation agent A, it is preferably diluted according to the saturated water holding capacity of the petroleum hydrocarbon-contaminated soil. Before composting and curing the petroleum hydrocarbon-contaminated soil, the saturated water holding capacity of the petroleum hydrocarbon-contaminated soil is 55%–65%. This invention preferably determines the dilution factor of multi-enzyme nano-remediation agent A based on the saturated water holding capacity of the petroleum hydrocarbon-contaminated soil. The dilution factor of multi-enzyme nano-remediation agent A is preferably 10 to 20 times, more preferably 16 times. In the embodiments of this invention, the dilution factor of multi-enzyme nano-remediation agent A is preferably 20 times.

[0083] After adding multi-enzyme nano-remediation agent B and multi-enzyme nano-remediation agent A to petroleum hydrocarbon-contaminated soil, this invention preferably uses water to adjust the saturated water holding capacity of the petroleum hydrocarbon-contaminated soil to 55%–65%, more preferably 60%. This invention does not have a specific limitation on the source of the water, but tap water is preferred. The 60% saturated water holding capacity of the soil in this invention refers to a soil moisture content of 25%–30%. At this saturated water holding capacity, the water requirements for the reproduction of indigenous microorganisms in the petroleum hydrocarbon-contaminated soil can be guaranteed, and relatively good aeration can be ensured, maintaining a certain oxygen concentration in the soil. This invention preferably maintains a soil saturated water holding capacity of 60% during the composting and curing process. If the soil saturated water holding capacity is low, water is preferably added during the turning process.

[0084] The height of the pile in this invention is preferably 0.3m to 0.6m, more preferably 0.5m. The application effect of the multi-enzyme nano-remediation agent in this invention does not limit the length and width of the pile; the length and width can be determined based on the size of the soil being remediated and the actual conditions of the remediation site. In this invention, multi-enzyme nano-remediation agent B is preferably added to petroleum hydrocarbon-contaminated soil, followed by multi-enzyme nano-remediation agent A, before pile curing. This invention does not have specific limitations on the mixing parameters after adding multi-enzyme nano-remediation agent B and multi-enzyme nano-remediation agent A; it is sufficient to ensure that multi-enzyme nano-remediation agent A, multi-enzyme nano-remediation agent B, and petroleum hydrocarbon-contaminated soil are mixed evenly. The ambient temperature for remediation in this invention is preferably not lower than 15 degrees Celsius.

[0085] In this invention, if the degradation rate of petroleum hydrocarbons in the soil is less than 50% after 28-35 days of composting and curing, a second addition of multi-enzyme nano-remediation agent B is made. The preferred amount of multi-enzyme nano-remediation agent B added is 0.5%-1% of the mass of the petroleum hydrocarbon-contaminated soil, more preferably 0.5%. The second addition of multi-enzyme nano-remediation agent B in this invention can improve the remediation effect of the multi-enzyme nano-remediation agent.

[0086] The preferred remediation time according to this invention is 40-70 days per cycle. This 40-70 days constitutes one remediation cycle. After one remediation cycle, the petroleum hydrocarbon content in the contaminated soil is tested. If it is within acceptable limits, the contaminated soil is removed. If it is not, this invention preferably continues to add a multi-enzyme remediation agent for a second remediation cycle until the petroleum hydrocarbon contaminated soil is remediated to a satisfactory level. The satisfactory remediation of petroleum hydrocarbon contaminated soil according to this invention means that the mass content of petroleum hydrocarbons in the contaminated soil is less than 0.3%. The specific remediation time is adjusted according to the mass content percentage of petroleum hydrocarbons in the contaminated soil. If the mass content percentage of petroleum hydrocarbons in the contaminated soil is less than 0.3% after 28 days of remediation, it is considered that the remediation is complete.

[0087] In the remediation process described in this invention, it is preferable to turn the soil over once a week. This invention does not have any particular limitation on the method of turning the soil over; conventional methods are acceptable. The purpose of turning the soil over in this invention is to increase the oxygen concentration in petroleum hydrocarbon-contaminated soil, release carbon dioxide from the petroleum hydrocarbon-contaminated soil, and ensure that the indigenous microorganisms have the oxygen required for growth and reproduction.

[0088] Existing technologies often suffer from long remediation cycles and unsatisfactory results due to the diversity of petroleum hydrocarbon pollution and the influence of soil type, permeability, water retention, pH, oxygen content, organic matter content, and ambient temperature on the effectiveness of bioremediation. This invention, through the combined effects of specific multi-enzyme remediation agent components, specific ambient temperature, soil turning, soil saturation water holding capacity, and pH value, shortens the remediation cycle of petroleum hydrocarbon-contaminated soil. The multi-enzyme nano-remediation agent described in this invention degrades petroleum hydrocarbon pollutants into carbon dioxide and water or transforms them into low-toxicity, low-mobility substances such as fatty acids, carboxylic acids, and alkyl hydrogen peroxide, rapidly restoring the basic properties of the soil. This low-cost approach aligns with national environmental protection policies and achieves the goal of petroleum hydrocarbon pollution remediation.

[0089] This invention's multi-enzyme nano-remediation agent can achieve in-situ remediation of petroleum hydrocarbon-contaminated soil. The dosage of the multi-enzyme nano-remediation agent is determined based on the extent of petroleum hydrocarbon contamination through geological surveys. The volume of soil contaminated with petroleum hydrocarbons is then calculated, and the required mass of soil to be treated is determined using bulk density. The multi-enzyme nano-remediation agent is then added according to the specified proportions. However, in-situ remediation of petroleum hydrocarbon-contaminated soil requires careful attention to avoid excessive water addition during tilling; otherwise, leachate from the contaminated soil may settle, leading to an expansion of the petroleum hydrocarbon contamination area.

[0090] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0091] This invention relates to the remediation of petroleum hydrocarbon-contaminated soil according to a specific application procedure for a multi-enzyme remediation agent. The specific application procedure for the multi-enzyme remediation agent is detailed below. Figure 1 .

[0092] In the following examples and comparative examples, the amount of both multi-enzyme nano-repair agent A and multi-enzyme nano-repair agent B prepared in advance is 3000g.

[0093] Example 1

[0094] (1) Composition of multi-enzyme nano-repair agent A and multi-enzyme nano-repair agent B

[0095] The mass of each component of the multi-enzyme nano-repair agent A is as follows: 450g sugarcane molasses, 390g chitosan, 150g wheat bran, 75g oxidase, 60g dried yeast, 15g papain, 30g cellulase (enzyme activity greater than 60,000 units), 180g castor oil, and 1650g water.

[0096] The mass of each component of the multi-enzyme nano-repair agent B is as follows: 720g peanut shell powder, 1200g monoammonium phosphate, 210g ferrous sulfate, 750g modified shell powder, 18g nano silica, and 102g vegetable oil.

[0097] (2) Preparation of multi-enzyme nano-repair agent A and multi-enzyme nano-repair agent B

[0098] Liquid multi-enzyme nano-repair agent A is prepared as follows: First, prepare a temperature-adjustable container. Dissolve the sugarcane molasses evenly with water according to the mass of each component in step (1). Then, add chitosan, wheat bran, oxidase, dry yeast, papain, and cellulase to the container in sequence. Stir evenly and heat to 28°C for 3 days. After 3 days, add castor oil and stir evenly. Cool the mixture to room temperature. Liquid multi-enzyme repair agent A is now ready.

[0099] The preparation method of multi-enzyme nano-repair agent B is as follows: Prepare a mixer, and add peanut shell powder, monoammonium phosphate, ferrous sulfate, modified shell powder and nano silica to the mixer in sequence according to the mass of each component in step (1). Then start the mixer to mix. During the mixing process, spray vegetable oil to modify the mixture. The mixing speed is 20 r / min and the mixing time is 4 min. Stop mixing to obtain multi-enzyme nano-repair agent B.

[0100] Specific application process:

[0101] 1. Case Study Details: This petroleum hydrocarbon contaminated site is located in North China, and the contaminated soil originated from leaks during oil extraction. The soil itself has a very high concentration of petroleum hydrocarbons, reaching 59,656 mg / kg, and is grayish-black in color with a strong, pungent odor. The remediation objective is to reduce the petroleum hydrocarbon content in the contaminated soil to <0.3%.

[0102] 2. Repair steps:

[0103] (1) First, take 100 kg of soil contaminated by petroleum hydrocarbons, dry the soil until the moisture content is less than 15%, remove impurities, and then crush and homogenize it using a mixer. The particle size of the homogenized soil is no more than 2 cm.

[0104] (2) The pH of the soil contaminated with petroleum hydrocarbons after homogenization in step (1) was measured. The pH value was 7.68, and no pH adjustment was required.

[0105] (3) Based on the test data of the blank sample of petroleum hydrocarbon-contaminated soil (the content of petroleum hydrocarbon is 59656 mg / kg), weigh 2 kg of multi-enzyme nano-remediation agent B with a mass ratio of 2% of petroleum hydrocarbon-contaminated soil, add it to the contaminated oil sludge, and mix it evenly.

[0106] (4) Based on the content of petroleum hydrocarbons in the blank oil sludge sample being 59656 mg / kg, weigh 1.8 kg of multi-enzyme nano-remediation agent A, which accounts for 1.8% of the mass of petroleum hydrocarbon-contaminated soil. Dilute it with water to 20 times and spray it evenly on the petroleum hydrocarbon-contaminated soil obtained in step (3).

[0107] (5) The petroleum hydrocarbon contaminated soil that has been treated with multi-enzyme nano-repair agents A and B in step (4) is made into an oil sludge biomass. The biomass size is approximately 1m*0.4m*0.3m (length*width*height). Tap water is sprayed according to the water content of the petroleum hydrocarbon contaminated soil to make the saturated water holding rate of the petroleum hydrocarbon contaminated soil reach 60% (equivalent to a soil water content of 25% to 30%) for maintenance. The saturated water holding rate of the contaminated soil is maintained at 60±5% throughout the maintenance process.

[0108] (6) The ambient temperature for maintenance should be between 18 and 25℃, and the soil should be turned over once a week;

[0109] (7) After six weeks of maintenance, once the repair goal is achieved, maintenance should be stopped.

[0110] During the maintenance process, samples were taken and tested weekly using gas chromatography (HJ1021-2019). Specific data are shown in Table 1 and... Figure 2 .according to Figure 2 As shown in Table 1, the multi-enzyme nano-remediation agent of the present invention achieves the remediation target for petroleum hydrocarbon-contaminated soil.

[0111] Example 2

[0112] The specific components of multi-enzyme nano-repair agent A and multi-enzyme nano-repair agent B are as follows:

[0113] The mass of each component of the multi-enzyme nano-repair agent A is as follows: 480g sugarcane molasses, 450g chitosan, 180g wheat bran, 30g oxidase, 45g dried yeast, 15g papain, 15g cellulase (enzyme activity greater than 60,000 units), 90g castor oil, and 1695g water.

[0114] The mass of each component of the multi-enzyme nano-repair agent B is as follows: 750g peanut shell powder, 1140g monoammonium phosphate, 150g ferrous sulfate, 801g modified shell powder, 24g nano silica, and 135g vegetable oil.

[0115] The preparation method and repair steps of the multi-enzyme nano-repair agent are the same as in Example 1. The repair target is achieved after 7 weeks of maintenance, and maintenance is then stopped.

[0116] Example 3

[0117] The specific components of multi-enzyme nano-repair agent A and multi-enzyme nano-repair agent B are as follows:

[0118] The mass of each component of the multi-enzyme nano-repair agent A is as follows: 300g sugarcane molasses, 300g chitosan, 30g wheat bran, 90g oxidase, 75g dried yeast, 30g papain, 45g cellulase (enzyme activity greater than 60,000 units), 210g castor oil, and 1650g water.

[0119] The mass of each component of the multi-enzyme nano-repair agent B is as follows: 720g peanut shell powder, 1200g monoammonium phosphate, 210g ferrous sulfate, 750g modified shell powder, 18g nano silica, and 102g vegetable oil.

[0120] The preparation method and repair steps of the multi-enzyme nano-repair agent are the same as in Example 1. The repair target is achieved after 8 weeks of maintenance, and maintenance is then stopped.

[0121] Comparative Example 1

[0122] Only the enzyme nano-remediation agent A prepared in Example 1 was used for the maintenance of petroleum hydrocarbon contaminated soil, and the rest was the same as in Example 1.

[0123] Comparative Example 2

[0124] Only the enzyme nano-remediation agent B from Example 1 was used for the maintenance of petroleum hydrocarbon contaminated soil; the rest was the same as in Example 1.

[0125] Comparative Example 3

[0126] The components of the multi-enzyme nano-repair agent A are: 480g sugarcane molasses, 420g chitosan, 210g wheat bran, 0g oxidase, 0g dried yeast, 0g papain, 0g cellulase, 210g castor oil, and 1680g water.

[0127] The components of the multi-enzyme nano-repair agent B are as follows: 720g peanut shell powder, 1200g monoammonium phosphate, 210g ferrous sulfate, 750g modified shell powder, 18g nano silica, and 102g vegetable oil.

[0128] The preparation method and repair steps of the multi-enzyme nano-repair agent are the same as in Example 1, and the maintenance lasts for 8 weeks.

[0129] Comparative Example 4

[0130] The mass of each component of the multi-enzyme nano-repair agent A, with only the following compound enzymes added: 0g sugarcane molasses, 0g chitosan, 0g wheat bran, 75g oxidase, 60g dried yeast, 15g papain, 30g cellulase, 0g castor oil, and 2820g water.

[0131] The mass of each component of the multi-enzyme nano-repair agent B is as follows: 720g peanut shell powder, 1200g monoammonium phosphate, 210g ferrous sulfate, 750g modified shell powder, 18g nano silica, and 102g vegetable oil.

[0132] The preparation method and repair steps of the multi-enzyme nano-repair agent are the same as in Example 1, and the maintenance lasts for 8 weeks.

[0133] Comparative Example 5 (Multi-enzyme nano-repair agent B without added monoammonium phosphate)

[0134] The mass of each component of the multi-enzyme nano-repair agent A is as follows: 450g sugarcane molasses, 390g chitosan, 150g wheat bran, 75g oxidase, 60g dried yeast, 15g papain, 30g cellulase (enzyme activity greater than 60,000 units), 180g castor oil, and 1650g water.

[0135] The mass of each component of the multi-enzyme nano-repair agent B is as follows: peanut shell powder 1200g, monoammonium phosphate 0g, ferrous sulfate 210g, modified shell powder 1470g, nano silica 18g, and vegetable oil 102g.

[0136] The preparation method and repair steps of the multi-enzyme nano-repair agent are the same as in Example 1, and the maintenance lasts for 8 weeks.

[0137] During the maintenance process, samples were taken and tested weekly for Examples 1-3 and Comparative Examples 1-5 using gas chromatography (HJ1021-2019). Specific data are shown in Table 1 and... Figures 2-9 .according to Figures 2-9 As shown in Table 1, the multi-enzyme nano-remediation agent of this invention can achieve a remediation standard of less than 0.3% petroleum hydrocarbon content in soil contaminated with petroleum hydrocarbons after 8 weeks of curing, provided the petroleum hydrocarbon content in the soil is no more than 6%. In contrast, the petroleum hydrocarbon content in the soil of Comparative Example 1 did not change significantly after 8 weeks of curing, indicating a poor remediation effect. This demonstrates that without adding suitable nutrients for microbial growth and reproduction during the biological remediation of petroleum hydrocarbon-contaminated soil, microorganisms have difficulty multiplying, and their biodegradation effect on petroleum hydrocarbons is negligible.

[0138] Although the content of petroleum hydrocarbons in the soil decreased after 8 weeks of maintenance in Comparative Example 2, it was far from meeting the remediation standard of less than 0.3% by mass of petroleum hydrocarbons. The data from Comparative Example 2 show that when biological methods are used to remediate petroleum hydrocarbon-contaminated soil, only the appropriate nutrients required for the growth and reproduction of microorganisms are added, without the addition of coenzymes. The microbial reproduction rate is not fast, but the microorganisms have a certain activity and can degrade petroleum hydrocarbons in the soil, but the rate is slow until the degradation stops.

[0139] Comparative Example 3, which contains multi-enzyme nano-repair agent A, did not contain any compound enzymes. Its repair effect was similar to that of Comparative Example 2, and it did not achieve the repair target of having a petroleum hydrocarbon content of less than 0.3%.

[0140] In Comparative Example 4, the complex enzymes in the multi-enzyme nano-remediation agent were not fully activated, resulting in a very low concentration of extracellular enzymes in the microorganisms after being added to the contaminated soil. This caused the microorganisms to lose their catalytic activity and fail to promote the degradation of petroleum hydrocarbons.

[0141] Comparative Example 5, the multi-enzyme nano-remediation agent B, did not contain monoammonium phosphate. The multi-enzyme nano-remediation agent contained very little nitrogen and phosphorus, which could not meet the needs of soil microbial growth and reproduction. Therefore, the petroleum hydrocarbons in this comparative example did not undergo degradation.

[0142] Table 1. Total petroleum hydrocarbon content detection data during maintenance (unit: mg / kg)

[0143]

[0144]

[0145] Example 4

[0146] The components of multi-enzyme nano-repair agent A and multi-enzyme nano-repair agent B in this implementation case are the same as those in Example 1.

[0147] (I) Sources of contaminated soil

[0148] The contaminated soil used in this experiment came from the Daqing Oilfield Oil Production Plant and was divided into four groups: Experiment 1, Experiment 2, Experiment 3, and Experiment 4. The soil appeared yellowish-black and had a pungent odor. The petroleum hydrocarbon content in the contaminated soil ranged from 0.8% to 6%. The remediation goal of this experiment was to reduce the petroleum hydrocarbon content to below 2%, with a target of less than 0.3%.

[0149] (II) Experimental Operation

[0150] (1) Four maintenance areas were built in the warehouse provided by the oil field. Waterproof tarpaulins were laid on the ground part of each area, and a brick was placed around the perimeter to prevent leachate from overflowing.

[0151] (2) The contaminated soil provided by the oilfield was spread evenly in the corresponding numbered maintenance area and fully homogenized. The numbers 1, 2, 3 and 4 correspond to Experiment 1, Experiment 2, Experiment 3 and Experiment 4 respectively. Experiment 1: 500 kg of petroleum hydrocarbon contaminated soil; Experiment 2: 500 kg of petroleum hydrocarbon contaminated soil; Experiment 3: 500 kg of petroleum hydrocarbon contaminated soil; Experiment 4: 300 kg of petroleum hydrocarbon contaminated soil.

[0152] (3) Add 2% by mass of multi-enzyme nano-repair agent B to No. 1, No. 2 and No. 3 respectively, and add 1% of multi-enzyme nano-repair agent B to No. 4. Stir for 15 minutes to mix the multi-enzyme nano-repair agent B evenly with the soil. Then add 1.5% of multi-enzyme nano-repair agent A and stir evenly. Then add water to adjust the soil moisture to 60% of the soil saturation water holding capacity to ensure that the soil is moist, loose and free of water stains. Place it indoors for maintenance.

[0153] (4) For the first two weeks, turn the soil and aerate it twice a week. After that, turn the soil and aerate it once a week. If the soil dries out, spray an appropriate amount of water, mix it evenly, and continue to maintain it.

[0154] (5) When the experiment reached day 35, 0.5% by mass of multi-enzyme nano-repair agent B was added to No. 1, No. 2 and No. 3 respectively, and after mixing evenly, the product was maintained.

[0155] (6) Samples were taken every 15 days to analyze the repair progress, and the repair was maintained for 60 days. The results of this experiment were summarized.

[0156] (III) Test Results

[0157] In this experiment, 2.5% by mass of multi-enzyme nano-repair agent B was added to samples 1, 2, and 3, and 1% by mass of multi-enzyme nano-repair agent B was added to sample 4. The moisture content was maintained at 60%, and the average indoor temperature was maintained between 19°C and 20°C. The experiment lasted for 60 days. After the experiment, the petroleum hydrocarbon content was detected using the same method as in Example 1, as shown in Table 2. Figure 10 According to Table 2 and Figure 10 It can be seen that the application effect of the multi-enzyme nano-repair agent is very good, achieving the experimental results. Supplementing the multi-enzyme nano-repair agent a second time during the repair process will result in an even better final repair effect.

[0158] Table 2. Measurement results of petroleum hydrocarbon content before and after remediation for samples 1-4.

[0159] Petroleum hydrocarbon content No. 1 No. 2 No. 3 No. 4 Original data (mg / kg) before repair 36000 56000 55000 8200 Data after 60 days of maintenance (mg / kg) 2270 1450 2680 520

[0160] In summary, the multi-enzyme nano-remediation agent provided by this invention has a short bioremediation cycle and high remediation efficiency for petroleum hydrocarbon pollution, and has broad application prospects.

[0161] The multi-enzyme nano-remediation agent provided by this invention has a good remediation effect and can overcome the adverse effects of the diversity of petroleum hydrocarbon pollution and the soil type, permeability, water retention, pH, oxygen content, organic matter content and ambient temperature on the remediation effect.

[0162] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. The application of a multi-enzyme nano-remediation agent in the remediation of petroleum hydrocarbon-contaminated soil, characterized in that, The multi-enzyme nano-repair agent includes multi-enzyme nano-repair agent A and multi-enzyme nano-repair agent B; By weight percentage, the multi-enzyme nano-repair agent A comprises 10%–20% sugarcane molasses, 10%–20% chitosan, 1%–10% wheat bran, 1%–5% oxidase, 1%–5% dried yeast, 0.5%–3% papain, 0.5%–2% cellulase, 1%–10% castor oil, and 40%–60% water; By weight percentage, the multi-enzyme nano-repair agent B comprises 20%–30% peanut shell powder, 30%–50% monoammonium phosphate, 1%–10% ferrous sulfate, 20%–40% modified shell powder, 0.5%–1% nano-silica, and 1%–5% vegetable oil; The modified shell powder is obtained by grinding fresh shells after removing impurities and purifying them.

2. The application according to claim 1, characterized in that, The cellulase activity is greater than 60,000 U / mL.

3. The application according to claim 1 or 2, characterized in that, The preparation method of the multi-enzyme nano-repair agent includes the following steps: Water, sugarcane molasses, chitosan, wheat bran, oxidase, dry yeast, papain and cellulase were mixed and kept warm, and then castor oil was added to obtain multi-enzyme nano-repair agent A. Peanut shell powder, monoammonium phosphate, ferrous sulfate, modified shell powder, and nano-silica were mixed in a second mixture. Vegetable oil was sprayed in during the second mixing process to obtain multi-enzyme nano-repair agent B.

4. The application according to claim 3, characterized in that, The insulation temperature is 26–35°C, and the insulation time is 2–4 days.

5. The application according to claim 3, characterized in that, The second mixing is a stirring mixing, wherein the stirring speed is 15-25 r / min and the stirring time is 3-5 min.

6. The application according to claim 1, characterized in that, The application includes: adding multi-enzyme nano-remediation agent B to petroleum hydrocarbon-contaminated soil, followed by adding multi-enzyme nano-remediation agent A for composting and curing for 28-35 days; if the degradation rate of petroleum hydrocarbons in the soil is less than 50%, then adding multi-enzyme nano-remediation agent B a second time; after adding the multi-enzyme nano-remediation agent, adjusting the saturated water holding capacity of the petroleum hydrocarbon-contaminated soil to 55%-65%, and the pH value of the petroleum hydrocarbon-contaminated soil to 6-8.

7. The application according to claim 6, characterized in that, The temperature for the repair is not lower than 15°C, and the pile is turned over 1 to 2 times per week during the repair process.

8. The application according to claim 1, characterized in that, When the mass content of petroleum hydrocarbons in the contaminated soil does not exceed 6%, the amount of multi-enzyme nano-remediation agent A added is 0.5% to 2% of the mass of the petroleum hydrocarbon-contaminated soil, and the amount of multi-enzyme nano-remediation agent B added is 0.5% to 3% of the mass of the petroleum hydrocarbon-contaminated soil.

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