CN114395402A

CN114395402A - Composition for removing organic pollutants from farmland soil and application thereof

Info

Publication number: CN114395402A
Application number: CN202210066599.3A
Authority: CN
Inventors: 王星皓; 高娟; 方国东; 王玉军
Original assignee: Institute of Soil Science of CAS
Current assignee: Institute of Soil Science of CAS
Priority date: 2022-01-20
Filing date: 2022-01-20
Publication date: 2022-04-26
Anticipated expiration: 2042-01-20
Also published as: CN114395402B

Abstract

The invention provides a composition for removing organic pollutants from farmland soil and application thereof, belonging to the technical field of remediation and improvement of organic pollutants in farmland soil. According to the invention, the cheap trivalent manganese-sodium pyrophosphate complex and the bean pulp extracting solution are used as the composition, so that typical organic pollutants in farmland soil can be efficiently removed, the mineralization of soil organic matters and the damage to soil ecological functions can be effectively avoided, and meanwhile, the content of the soil organic matters can be obviously increased after the bean pulp extracting solution is used as an organic fertilizer. The scheme of the invention effectively avoids the potential secondary pollution problem in soil remediation, has obvious oxidation removal capability on organic pollutants in actual farmland soil, simultaneously prevents organic matters in the remedied soil from being damaged, effectively improves the content of organic matters in the soil, can be widely applied to removal of organic pollutants in farmland soil, is particularly suitable for high organic matter farmland soil, and provides a wide application prospect for remediation of organic pollution of the high organic matter soil.

Description

Composition for removing organic pollutants from farmland soil and application thereof

Technical Field

The invention relates to the technical field of soil organic pollution restoration and improvement, in particular to a composition for removing organic pollutants from farmland soil and application thereof.

Background

Organic pollution of soil is a current important environmental problem, and in recent years, persulfate-based advanced oxidation technology is also increasingly applied to the removal of organic pollutants in soil, underground water, surface water and sediments. In the application process of the advanced oxidation technology, oxidants such as persulfate and the like are activated by means of heat, ultraviolet light, transition metal, alkali and the like to generate sulfate radicals and hydroxyl radicals, so that the catalyst has strong oxidizing capability and good effect on removal of organic pollutants. However, the current advanced oxidation technology is widely applied to the field polluted soil remediation, and the farmland soil and the soil containing organic matters have fatal defects, such as harsh reaction conditions, high treatment cost, easy generation of byproducts with stronger toxicity and secondary salt pollution; more importantly, soil organic matters, soil structures, microorganisms and the like are destroyed, so that the soil organic matters are mineralized, and the nutrients are barren, even can not be recovered forever. For example, Chinese patent CN106753386B discloses a composition for treating high-concentration organophosphorus pesticide contaminated soil, which utilizes alkali to activate sodium persulfate to generate strong-oxidizing sulfate radicals and hydroxyl groups, can effectively degrade high-concentration organophosphorus pesticide in field soil, and is only suitable for treating high-concentration organophosphorus pesticide contaminated soil in field. The advanced oxidation technology mainly utilizes free radicals such as high-activity hydroxyl radicals and sulfate radicals formed to remove organic pollutants through oxidation, the free radicals have no selectivity and can oxidize various organic matters including soil organic matters, so that the soil organic matters are seriously damaged and even mineralized, and therefore, the advanced oxidation technology is not suitable for removing the organic pollutants in farmland soil. Therefore, the development of a remediation technology which is environmentally friendly and suitable for organically contaminated soil in a farmland is urgently needed.

At present, materials based on high-valence manganese oxidants are widely used for product agents for soil-underground water remediation and drinking water treatment, and mainly comprise potassium permanganate and manganese oxides. However, potassium permanganate is a mauve oxidant, which has strong oxidizability under acidic conditions, and a certain amount of potassium permanganate remains in the treated soil, so that the soil is mauve or red, and soil organic matters are damaged, so that the potassium permanganate is not suitable for farmland soil remediation. In the case of oxides of manganese, the oxides of manganese are present mainly in the form of brown particles, and the solubility thereof is very low, resulting in a reduced effect of removing pollutants from farmland soil. Due to the high heterogeneity of soil, these manganese oxide particle materials cannot be well applied to the remediation of organic pollution of farmland soil, so manganese-based materials with good dispersibility and easy mass transfer in soil need to be developed.

Research shows that a large amount of soluble trivalent manganese exists in water environment, sediment and soil environment generally, and exists mainly in the form of an environment ligand complex. Pyrophosphate (PP) widely exists in water environment and soil environment, can be used as an excellent chelating agent to complex trivalent manganese Mn (III) in the environment to form a stable trivalent manganese-sodium pyrophosphate complex (Mn (III) -PP), but cannot remove refractory organic pollutants in the environment due to limited oxidizing capability of Mn (III) -PP in the natural environment, thereby limiting the application of Mn (III) in soil remediation.

Disclosure of Invention

The invention aims to provide a composition for removing organic pollutants from farmland soil and application thereof, wherein the composition for removing organic pollutants from farmland soil realizes the restoration of Mn (III) in farmland organic polluted soil.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a composition for removing organic pollutants from farmland soil, which comprises a trivalent manganese-sodium pyrophosphate complex solution and a soybean meal extracting solution, wherein the concentration of the trivalent manganese-sodium pyrophosphate complex solution is 5-50 mmol/L, and the total concentration of active ingredients in the soybean meal extracting solution is 0.5-5 g/L.

Preferably, the volume ratio of the trivalent manganese-sodium pyrophosphate complex solution to the soybean meal extracting solution is 1 (0.5-10).

Preferably, the preparation method of the trivalent manganese-sodium pyrophosphate complex solution comprises the following steps:

mixing manganese dioxide, sodium pyrophosphate, sodium sulfite, water and a pH regulator to ensure that the pH value of the obtained mixed solution is 7.0-8.5, and carrying out reduction and complexation reaction to obtain a trivalent manganese-sodium pyrophosphate complex solution.

Preferably, the concentration of manganese dioxide in the mixed solution is 0.5-5 g/L, the concentration of sodium pyrophosphate is 0.1-1 mol/L, and the concentration of sodium sulfite is 2.5-25 mmol/L.

Preferably, the time of the reduction and complexation reaction is 1-2 h.

Preferably, the preparation method of the soybean meal extracting solution comprises the following steps:

mixing soybean meal with alkali liquor, leaching, performing intermittent ultrasonic extraction on the obtained leaching liquor, and filtering to obtain a soybean meal extracting solution.

Preferably, the dosage ratio of the soybean meal to the alkali liquor is 50-500 g: 1-2L, and the concentration of the alkali liquor is 10-20 mM; the leaching temperature is 40-60 ℃, and the leaching time is 3-8 days.

Preferably, the active ingredients in the soybean meal extracting solution comprise vanillin, apocynin and daidzein.

The invention provides application of the composition for removing organic pollutants in farmland soil in the technical scheme in treating organic pollutants in farmland polluted soil and improving soil organic matters.

Preferably, the mass ratio of the farmland polluted soil to the composition for removing the organic pollutants in the farmland soil is 1 (1-10).

The invention provides a composition for removing organic pollutants from farmland soil, which comprises a trivalent manganese-sodium pyrophosphate complex solution and a soybean meal extracting solution, wherein the concentration of the trivalent manganese-sodium pyrophosphate complex solution is 5-50 mmol/L, and the total concentration of active ingredients in the soybean meal extracting solution is 0.5-5 g/L. According to the invention, a cheap trivalent manganese-sodium pyrophosphate complex and a soybean meal extracting solution are used as a composition, trivalent manganese and active phenolic organic matters (including vanillin, apocynin and daidzein) in the soybean meal extracting solution respectively and correspondingly form phenolic oxygen organic free radicals (including vanillin phenolic oxygen free radicals, apocynin phenolic oxygen free radicals and daidzein phenolic oxygen free radicals) with higher activity, and the free radicals further undergo degradation reaction with more inert organic pollutants in soil, so that the organic pollutants in farmland soil are efficiently removed. Meanwhile, the phenol functional group of the active phenol organic matter in the bean pulp extracting solution can be converted into a benzoquinone functional group after reaction, the structure is stable, and the benzoquinone functional group can be stored in soil for a long time, so that the effect of improving the organic matter content of the soil is achieved, and therefore the bean pulp extracting solution can be used as an organic fertilizer and can obviously increase the organic matter content of the soil.

Active species generated in the process of degrading organic pollutants by the composition provided by the invention are phenoxy free radicals, and the composition is environment-friendly to organic matters, so that the mineralization of the organic matters in soil is avoided; while the traditional advanced oxidation soil remediation technology removes pollutants, soil organic matters are mineralized, so that the ecological function is damaged.

The composition disclosed by the invention is simple in preparation method, low in cost, economic and feasible, environment-friendly and high in efficiency, effectively avoids the potential secondary pollution problem in soil remediation, has obvious oxidation removal capability on organic pollutants in actual farmland soil, simultaneously prevents organic matters in the remedied soil from being damaged, effectively improves the content of the organic matters in the soil, can be widely applied to removal of the organic pollutants in the farmland soil, is particularly suitable for high-organic-matter farmland soil, and provides a wide application prospect for organic pollution remediation of the high-organic-matter soil.

The results of application examples show that the composition formed by the trivalent manganese-sodium pyrophosphate complex solution and the soybean meal extracting solution is used for removing organic pollutants in farmland soil, and has the characteristics of good oxidation activity, high utilization rate, short reaction time, high removal efficiency, environmental friendliness and the like. After 4 hours of treatment, the conversion rate of organic pollutants in farmland soil reaches 58.2-96.6%. In addition, compared with the prior advanced oxidation technology, the composition provided by the invention cannot damage organic matters in soil in the farmland soil remediation process. The active organic components in the bean pulp extracting solution can enhance the removal of organic pollutants, and can be used as a good organic fertilizer to increase the content of organic matters in soil.

Drawings

FIG. 1 is a UV-Vis spectrum of a trivalent manganese-sodium pyrophosphate complex solution prepared in example 1;

FIG. 2 is a graph showing the concentration of trivalent manganese-sodium pyrophosphate complex solutions prepared in examples 1, 2 and 3 as a function of incubation time;

FIG. 3 is a standard graph of representative phenolic active content in example 1, expressed as gallic acid equivalent (mg/L);

FIG. 4 shows the effect of different extraction times on the total active substance content of the soybean meal extract in examples 1, 4 and 5 and comparative examples 1-2.

Detailed Description

In the present invention, unless otherwise specified, all the starting materials required for the preparation are commercially available products well known to those skilled in the art.

The composition for removing organic pollutants from farmland soil comprises a trivalent manganese-sodium pyrophosphate complex solution, wherein the concentration of the trivalent manganese-sodium pyrophosphate complex solution is 5-50 mmol/L, and preferably 10 mmol/L.

In the invention, the volume ratio of the trivalent manganese-sodium pyrophosphate complex solution to the soybean meal extracting solution is preferably 1 (0.5-10), and more preferably 1 (5-10).

In the present invention, the method for preparing the trivalent manganese-sodium pyrophosphate complex solution preferably includes the steps of:

In the present invention, the pH adjusting agent is preferably hydrochloric acid; the concentration of the hydrochloric acid is not particularly limited in the present invention, and commercially available hydrochloric acid known in the art may be used. In the invention, the concentration of manganese dioxide in the mixed solution is preferably 0.5-5 g/L, and more preferably 1 g/L; the concentration of sodium pyrophosphate is preferably 0.1-1 mol/L, and the concentration of sodium sulfite is preferably 2.5-25 mmol/L. The invention uses sodium sulfite as a reducing agent to perform reduction reaction with manganese dioxide to form trivalent manganese, and simultaneously, the chelating agent sodium pyrophosphate is complexed with the generated trivalent manganese, thereby forming a stable trivalent manganese-sodium pyrophosphate complex solution.

In the invention, the manganese dioxide, sodium pyrophosphate, sodium sulfite, water and a pH regulator are mixed to ensure that the pH value of the obtained mixed solution is 7.0-8.5, preferably, the sodium pyrophosphate is dissolved in water in the process of carrying out reduction and complexation reaction, the sodium pyrophosphate is placed on a magnetic stirrer for stirring, hydrochloric acid (with the concentration of 1M) is dripped into the obtained solution to regulate the pH value to 7.0-8.5, and the acid addition is stopped; adding manganese dioxide into the obtained solution, performing ultrasonic dispersion uniformly, adding sodium sulfite into the obtained dispersion liquid, stirring on a magnetic stirrer, performing reduction and complexation reaction until manganese dioxide particles in the solution disappear, standing for 30min, centrifuging to remove insoluble substances, and obtaining supernatant, namely the trivalent manganese-sodium pyrophosphate complex solution. The process of the dropping, stirring and centrifuging is not particularly limited in the present invention, and may be performed according to a process well known in the art.

In the present invention, the temperature of the reduction + complexation reaction is preferably room temperature, i.e. no additional heating or cooling is performed; the time is preferably 1-2 h; the reduction and complexation reaction is preferably carried out under the conditions of ultrasound and stirring; the process of the present invention for the ultrasonic treatment and the stirring is not particularly limited, and may be performed according to a process well known in the art.

In the present invention, the reaction formula for synthesizing the trivalent manganese-sodium pyrophosphate complex is 2Mn (VI) O₂+Na₂SO₃+10PP→2Mn(III)-PP。

The composition for removing organic pollutants in farmland soil comprises a soybean meal extracting solution, wherein the total concentration of active ingredients in the soybean meal extracting solution is 0.5-5 g/L, and preferably 5 g/L; the active ingredients in the bean pulp extracting solution preferably comprise vanillin, oleander and daidzein.

In the present invention, the preparation method of the soybean meal extracting solution preferably includes the following steps:

mixing soybean meal with alkali liquor, leaching, performing ultrasonic extraction on the obtained leaching liquor, and filtering to obtain a soybean meal extracting solution.

In the invention, the soybean meal is preferably commercial soybean meal particles; in the embodiment of the invention, the soybean meal is first soaked in the oil mill, and more preferably, the soybean meal is first soaked by-product after soybean oil is extracted from soybeans; the first-time soybean meal soaked in the oil mill is preferably dried, crushed and sieved by a 40-mesh sieve in sequence before use. The drying and pulverizing processes are not particularly limited in the present invention, and may be performed according to processes well known in the art.

In the invention, the alkali in the alkali liquor is preferably sodium hydroxide; the dosage ratio of the soybean meal to the alkali liquor is preferably 50-500 g: 1-2L, and the concentration of the alkali liquor is preferably 10-20 mM.

The process of mixing the soybean meal and the alkali liquor is not particularly limited, and the materials are uniformly mixed according to the process known in the field.

In the invention, the leaching is preferably carried out in an incubator under the condition of shaking, and the speed of the shaking is preferably 100-180 rpm, and more preferably 120 rpm; the leaching temperature is preferably 40-60 ℃, the leaching time is preferably 3-8 days, and more preferably 4-6 days.

After the leaching is finished, the obtained leaching liquor is preferably subjected to ultrasonic extraction; the ultrasonic extraction is preferably carried out in an ultrasonic cleaner, the power of the ultrasonic extraction is preferably 60W, and the time of the ultrasonic extraction is preferably 20-40 min, and more preferably 30 min.

After the ultrasonic extraction is finished, the obtained extracting solution is preferably filtered by a 0.45mm cellulose filter membrane, the obtained supernatant is the soybean meal extracting solution, and the soybean meal extracting solution is stored at 4 ℃. The filtration process is not particularly limited in the present invention, and may be performed according to a process well known in the art.

In the composition for removing organic pollutants in farmland soil, the trivalent manganese-sodium pyrophosphate complex solution and the bean pulp extracting solution interact to generate a large amount of organic free radicals taking active ingredients of the bean pulp extracting solution as the center, so that the organic pollutants can be promoted to react, and the organic pollutants in the farmland soil can be effectively removed. Meanwhile, the bean pulp extracting solution in the composition contains rich organic matters, and the organic matter content of the soil can be obviously improved after the bean pulp extracting solution is applied to farmland soil.

The preparation method of the composition for removing the organic pollutants in the farmland soil is not specially limited, and the composition can be prepared by mixing the trivalent manganese-sodium pyrophosphate complex solution and the soybean meal extracting solution according to the well-known process in the field; the mixing time is more preferably 10 to 20 min.

In the invention, the mass ratio of the farmland polluted soil to the composition for removing the organic pollutants in the farmland soil is preferably 1 (1-10). The application method is not specially limited, and the specific addition amount of the composition for removing the organic pollutants in the farmland soil in the farmland polluted soil can be adjusted according to actual requirements.

In the application example of the present invention, it is preferable that the application verification is performed by using the simulated contaminated soil and the actual contaminated soil, and the method for performing the application verification by using the simulated contaminated soil and the actual contaminated soil preferably includes the steps of:

adding the target organic pollutant mother liquor into farmland soil, stirring and mixing uniformly, and aging for 3 days to obtain polluted soil;

and mixing the contaminated soil with the composition for removing the organic pollutants in the farmland soil, performing degradation reaction, adding acetonitrile, extracting organic matters in the obtained soil, monitoring the change of the concentration of the pollutants in the contaminated soil by using high performance liquid chromatography, and calculating the degradation rate of the organic pollutants in the contaminated soil.

The method comprises the steps of adding the target organic pollutant mother liquor into farmland soil, uniformly stirring and mixing, and aging for 3 days to obtain the polluted soil.

The invention has no special limitation on the specific types of the target organic pollutants, and the organic pollutants in farmland soil well known in the field can be used; in an application example of the invention, the target organic pollutant in the target organic pollutant mother liquor is specifically pentachlorophenol or nicosulfuron; the concentration of the target organic contaminant mother liquor is preferably 100. mu. mol/L. The preparation process of the target organic pollutant mother liquor is not particularly limited in the invention, and the target organic pollutant mother liquor with the concentration is obtained according to the process well known in the art.

The farmland soil is not specially limited, and the farmland soil with known sources in the field can be used; in an application example of the invention, the soil is black soil of Helen of Heilongjiang or tidal soil of Shandong chat.

In the invention, the dosage ratio of the target organic pollutant mother liquor to farmland soil is preferably 10mL:100 g; the concentration of the organic pollutants in the polluted soil is preferably 10 mu mol/kg.

After the polluted soil is obtained, the invention preferably mixes the polluted soil with the composition for removing the organic pollutants in the farmland soil, performs degradation reaction, then adds acetonitrile to extract the organic matters in the obtained soil, monitors the change of the concentration of the pollutants in the polluted soil by utilizing high performance liquid chromatography, and calculates the degradation rate of the organic pollutants in the polluted soil.

In the invention, the mass ratio of the contaminated soil to the composition is preferably 1 (1-10).

In the present invention, the degradation reaction is preferably carried out in an incubator; the time of the degradation reaction is preferably adjusted according to the weight of the polluted soil, for example, 10g of the polluted soil is selected, and the time of the degradation reaction is 2-8 h.

In the target organic pollutant system, pentachlorophenol is subjected to dechlorination and polymerization reactions, and nicosulfuron is subjected to hydrolysis and intramolecular rearrangement reactions, so that organic pollutants in soil are removed.

The invention has no special limit on the using amount of the acetonitrile, and the acetonitrile can be adjusted according to actual requirements; the extraction time of the acetonitrile is not specially limited, and the extraction time can be adjusted according to the concentration change obtained by monitoring.

The invention has no special limitation on the process of monitoring the change of the pollutant concentration in the polluted soil by using the high performance liquid chromatography and calculating the degradation rate of the organic pollutants in the polluted soil, and the process is carried out according to the process known in the field.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Weighing 26.59g of sodium pyrophosphate, dissolving in 1L of deionized water, placing on a magnetic stirrer, stirring and dissolving, adjusting the pH to 8.0 by using 1M hydrochloric acid, adding 1g of manganese dioxide particles, and carrying out ultrasonic treatment on the obtained suspension to obtain a dispersion liquid;

630.2mg of sodium sulfite is weighed and dissolved in the dispersion liquid, and the mixture is continuously stirred under the ultrasonic condition to react for 2 hours to obtain clear pink solution; standing for 30min, centrifuging to remove insoluble substances, and collecting supernatant to obtain trivalent manganese-sodium pyrophosphate complex solution with concentration of 10 mmol/L;

drying and crushing first-soaked soybean meal in an oil mill, sieving with a 40-mesh sieve, weighing 500g of the obtained first-soaked soybean meal residue, placing the first-soaked soybean meal residue in a glass container, adding 2L of sodium hydroxide (10mM) solution, fully mixing and infiltrating, placing in a dark incubator at 40 ℃ and oscillating at the rotating speed of 120rpm for 4 days for leaching, carrying out ultrasonic treatment on the obtained leaching solution in a 60W ultrasonic cleaner for 30min, filtering the obtained extracting solution through a 0.45mM cellulose filter membrane to obtain a transparent pale yellow solution, namely a soybean meal extracting solution, and storing at 4 ℃;

and (3) mixing the trivalent manganese-sodium pyrophosphate complex solution and the soybean meal extracting solution for 20min in a volume ratio of 1:1 to obtain the composition.

Example 2

The only difference from example 1 is: when the trivalent manganese-sodium pyrophosphate complex solution was prepared, the amount of manganese dioxide particles added was 0.5g, and the amount of sodium sulfite added was 315mg (i.e., the concentration was 2.5mmol/L), to obtain a trivalent manganese-sodium pyrophosphate complex solution having a concentration of 5 mmol/L.

Example 3

The only difference from example 1 is: when the trivalent manganese-sodium pyrophosphate complex solution was prepared, the amount of manganese dioxide particles added was 5g, and the amount of sodium sulfite added was 3.15g (i.e., the concentration was 25mmol/L), to obtain a trivalent manganese-sodium pyrophosphate complex solution having a concentration of 50 mmol/L.

Example 4

The only difference from example 1 is: when preparing the soybean meal extracting solution, the leaching time is 3 days.

Example 5

The only difference from example 1 is: when preparing the soybean meal extracting solution, the leaching time is 5 days.

Example 6

The only difference from example 1 is: and mixing the trivalent manganese-sodium pyrophosphate complex solution and the soybean meal extracting solution for 20min in a volume ratio of 1:0.5 to obtain the composition.

Example 7

The only difference from example 1 is: and (3) mixing the trivalent manganese-sodium pyrophosphate complex solution and the soybean meal extracting solution for 20min in a volume ratio of 1:5 to obtain the composition.

Example 8

The only difference from example 1 is: and (3) mixing the trivalent manganese-sodium pyrophosphate complex solution and the soybean meal extracting solution for 20min in a volume ratio of 1:10 to obtain the composition.

Comparative example 1

The only difference from example 1 is: when preparing the soybean meal extracting solution, the leaching time is 1 day.

Comparative example 2

The only difference from example 1 is: when preparing the soybean meal extracting solution, the leaching time is 2 days.

Performance testing

1) The solutions of complex of trivalent manganese-sodium pyrophosphate prepared in examples 1, 2 and 3 were stored in a sealed state, incubated in a shaker at 25 ℃, 2mL of each solution was taken out of the cuvette at different incubation times (1, 2, 4, 8 and 15 days), abs at 258nm was measured using a UV-Vis spectrophotometer, the concentration of the corresponding Mn (III) -PP was calculated, and the change with time was observed, and the UV-Vis spectrogram results were shown in FIG. 1.

As shown in FIG. 1, a distinct characteristic absorption peak of Mn (III) -PP appears at 258nm, and the molar absorptivity of Mn (III) -PP at 258nm is 6750M^-1·cm^-1The concentrations of the Mn (III) -PP complexes prepared in examples 1, 2 and 3 were calculated from the extinction coefficient method to be 10, 5 and 50mmol/L, respectively.

FIG. 2 is a graph showing the change of the concentration of the trivalent manganese-sodium pyrophosphate complex solutions prepared in examples 1, 2 and 3 with the culture time, and it can be seen from FIG. 2 that the concentration of the trivalent manganese-sodium pyrophosphate complex solutions is maintained at 10, 5 and 50mM after the culture time is increased to 15 days, which indicates that the trivalent manganese-sodium pyrophosphate complex solutions prepared by the method have better stability.

2) The total active organic matter content of the soybean meal extract solutions prepared in examples 1, 4 and 5 was detected by Folin-Ciocalteu colorimetry, and since the active ingredients all belong to phenolic substances, gallic acid was selected as a representative phenolic substance to establish a standard curve, and the active substance content in the soybean meal extract solution was calculated by this method. The specific implementation is as follows:

preparing gallic acid standard solutions with gradient concentrations (5, 10, 20, 50, 100 and 200mg/L), mixing 0.5mL of the gallic acid standard solution with 2.5mL of Folin-Ciocalteu phenol reagent diluted by 10 times and 2mL of 7.5% sodium carbonate solution (w/v), shaking at 45 ℃ and in the dark for 15 minutes, and measuring the absorbance value at 765nm by using an ultraviolet-visible spectrophotometer to establish a gallic acid standard curve. Simultaneously, 0.5mL of the soybean meal extract prepared in the different cases and 2mL of the soybean meal extract prepared in the different cases are respectively added5mL of 10-fold diluted Folin-Ciocalteu phenol reagent was mixed with 2mL of 7.5% sodium carbonate (w/v) solution, reacted for 15 minutes according to the above conditions, and the absorbance value of the mixed solution at 765nm was measured. FIG. 3 is a graph of gallic acid standard curve established by the above method, wherein the standard curve equation is that y is 0.1463x-0.0022, R²Is 0.9998. The total content of active organic matters in the soybean meal extracting solution can be calculated according to the standard curve equation, and is expressed by gallic acid equivalent (GAE, g/L), and the results obtained in examples 1, 4 and 5 and comparative examples 1-2 are shown in figure 4.

FIG. 4 shows the effect of different extraction times on the total active substance content in the soybean meal extract, and it can be seen from FIG. 4 that the total active substance content in the soybean meal extract is 0.761g/L when the extraction time is 1 day, the concentration of the active ingredient is gradually increased along with the increase of the extraction time, and the total active substance content in the soybean meal extract reaches 2.419 and 4.252g/L when the extraction time is 2 days and 3 days, respectively. When the extraction time is 4 days, the total active substance content in the soybean meal extracting solution reaches 4.986g/L, and the total active substance content is kept at about 5g/L with further increase of time. Therefore, the extraction method of the invention can effectively extract the active substances in the soybean meal, and the optimal extraction time is 4 or 5 days.

Application example 1

1) Adopting a 250mL brown glass bottle as a reaction vessel, selecting black soil of Heilongjiang sea and Chaocheng of Shandong as 2 typical test soils (the specific physicochemical properties are shown in Table 1, the organic matter content of the soil is obviously different), respectively weighing 100g of the test soils in the reaction vessel, respectively adding 10mL of pentachlorophenol mother liquor (100 mu mol/L) and nicosulfuron mother liquor (100 mu mol/L) into the test soils, fully stirring and uniformly mixing, aging for 3 days, and respectively obtaining pentachlorophenol contaminated soil and nicosulfuron contaminated soil, wherein the concentrations of the pentachlorophenol contaminated soil and the nicosulfuron contaminated soil are both 10 mu mol/kg;

2) respectively weighing 10g of the polluted soil, correspondingly adding 10, 20, 50 and 100mL of the composition prepared in the example 1, performing degradation reaction under the conditions that the mass ratio of the polluted soil to the composition (namely the mass ratio of soil to water) is 1:1, 1:2, 1:5 and 1:10 respectively, standing in a constant temperature incubator (25 ℃), performing reaction for 4 hours, adding acetonitrile to extract organic matters in the polluted soil, monitoring the change of the concentration of pollutants by using high performance liquid chromatography, and calculating the degradation rate of the organic pollutants in the soil, wherein the specific results are shown in Table 2.

TABLE 1 physicochemical Properties of soil samples in different regions

TABLE 2 removal rate of organic contaminants in soil after 4h treatment of different soils with composition (%)

As can be seen from Table 2, in the composition-treated Heilongjiang Helan Black soil and Shandong chateau soil, pentachlorophenol and nicosulfuron were largely removed after 4 hours of reaction. Specifically, the removal rate of pentachlorophenol is 58.2-91.7%, the removal rate of nicosulfuron is 71.5-96.6%, and the removal rate of nicosulfuron is higher than that of pentachlorophenol. Under different soil-water ratio conditions, the higher the moisture content is, the higher the degradation efficiency of the two organic pollutants is, when the soil-water ratio is 1:10, the removal rates of pentachlorophenol and nicosulfuron in Heilonghai-Lon soil are respectively up to 87.2 and 93.5%, and the removal rates of pentachlorophenol and nicosulfuron in Shandong chat soil are respectively up to 91.7 and 96.6%. For two different soils, the removal rate of organic pollutants in the moisture soil of Shandong chat city is slightly higher than that of the black soil of Heilongjiang Helen, which may be related to the content of organic matters in the soil, as shown in Table 1, the content of organic matters in the black soil of Heilongjiang Helen is as high as 54.71g/kg, while the content of organic matters in the moisture soil of Shandong chat city is only 8.04g/kg, and part of organic pollutants are retained by high organic matters, so that the removal rate of the black soil is slightly lower, but the influence is not significant. Therefore, the composition has a good repairing effect in the organic polluted farmland soil.

Method comparison

To evaluate the effect of the composition of trivalent manganese-sodium pyrophosphate complex solution and soybean meal extract on the improvement of organic matter in farmland soil, the composition prepared in example 1 was compared with the effect of a typical advanced oxidation technology (alkali-activated Persulfate (PS)) on the organic matter content of soil:

selecting Shandong chateau moisture soil with low organic content, and investigating the change condition of the organic content of the soil after respectively applying the trivalent manganese-sodium pyrophosphate complex solution, the bean pulp extracting solution composition and the persulfate-alkali mixed solution.

Respectively weighing 10g of organic pollutant aged soil (the concentration of the organic pollutants is 10 mu mol/kg) prepared in the step 1) of the application example, placing the soil and the soil into a brown glass bottle, and mixing the soil and the water according to a soil-water mass ratio of 1:2, respectively adding 20mL of the trivalent manganese-sodium pyrophosphate complex solution prepared in the example 1, the soybean meal extracting solution composition and a persulfate-alkali mixed solution (the concentration of persulfate in the mixed solution is 10mmol/L, and the concentration of alkali (sodium hydroxide) is 100mmol/L), standing in a constant temperature incubator (25 ℃) for reaction; after the reaction for 1 day and 3 days, respectively taking out a proper amount of treated soil samples, air-drying, grinding to uniformly mix the soil samples, respectively taking out 3g of the soil samples, sieving all the soil samples, and filling the soil samples into brown ground bottles for later use; dripping a plurality of drops of 1M HCl into a soil sample, soaking for 20 minutes, then washing with deionized water, and airing; the treated samples were analyzed using a total organic carbon meter, and the results are shown in table 3.

TABLE 3 Change in organic matter of soils before and after treatment with the composition of example 1 and advanced Oxidation technology

As can be seen from Table 3, the organic matter content in the organically-polluted moisture soil before treatment was 8.01 to 8.06 g/kg. The soil-water mass ratio is 1: under the condition of 2, the polluted moisture soil is treated for 1 and 3 days by adopting the composition disclosed by the invention, the organic matter content in the moisture soil after 1 day of treatment is improved to 8.89-9.13 g/kg, and the organic matter content in the moisture soil is still maintained at 9.06-9.17 g/kg after the treatment time is prolonged to 3 days, which shows that the composition has no destructive effect on the organic matters in the soil when being used for treating the organic pollutants in the soil, and meanwhile, the organic components in the composition can improve the organic matter content in the soil to a certain extent. Compared with the prior art, after the persulfate-alkali mixed solution is applied to treat the organic contaminated soil for 1 day, the organic matter content of the soil is obviously reduced to 5.44-5.81 g/kg, the organic matter content is further reduced to 4.63-4.76 g/kg along with the prolonging of the treatment time to 3 days, the organic matter content is reduced by 40.9-42.2 percent compared with the organic matter content of the original soil, and the soil component structure is seriously damaged. This shows that the traditional advanced oxidation technology has good pollutant removal capability, but has great destruction effect on organic matters in soil, and is not suitable for organic pollution remediation of farmland soil. Compared with the prior art, the composition provided by the invention is an environment-friendly treating agent, and can effectively remove organic pollutants and improve the content of organic matters in soil to a certain extent, so that the scheme provided by the invention has obvious superiority and can be better suitable for restoring organic pollution of farmland soil.

Application example 2

The compositions of the trivalent manganese-sodium pyrophosphate complex solution and the soybean meal extract solution described in examples 1, 6, 7 and 8 were applied to actual contaminated farmland soil derived from actual organic pesticide-contaminated paddy field soil, respectively, and the kinds of the organic pesticides included: atrazine (10.6mg/kg), pentachlorophenol (2.5mg/kg), benzylchlorophenol (1.3mg/kg) and nicosulfuron (7.2 mg/kg).

The degradation procedure was the same as in application example 1: weighing 10g of the organic pesticide contaminated soil, placing the soil in a brown glass bottle, and mixing the soil and the water according to a soil-water mass ratio of 1:2, 20mL of the trivalent manganese-sodium pyrophosphate complex solution prepared in examples 1, 6, 7 and 8 and the soybean meal extract composition were added, respectively, and left to stand in a constant temperature incubator (25 ℃) to react; after 4 hours of reaction, acetonitrile is added to extract organic matters in the polluted soil, the change of the concentration of the pollutants is monitored by using high performance liquid chromatography, the degradation rate of the organic pollutants in the actual polluted farmland soil is calculated, and specific results are shown in table 4.

TABLE 4 removal of four organic contaminants from contaminated field soil after treatment with the compositions prepared in examples 1, 6, 7 and 8, respectively

As can be seen from Table 4, the contaminated paddy soil treated with the compositions of examples 1, 6, 7 and 8 (i.e., the compositions in the volume ratios of 1:0.5, 1:1, 1:5 and 1:10, respectively) was largely removed after reacting atrazine, pentachlorophenol, benzylchlorophenol and nicosulfuron for 4 hours. When the volume ratio of the composition is 1:0.5, the removal rate of the four organic matters is 89.1-97.3%; when the volume ratio of the composition is 1:1, the removal rate of the four organic matters is 85.6-94.8%; when the volume ratio of the composition is 1:5 and 1:10, the removal rate of four organic matters is reduced and is distributed between 74.0 and 85.6 percent. This is due to the fact that as the ratio is increased, the concentration of the trivalent manganese-sodium pyrophosphate complex in the composition decreases. Therefore, the composition has a good farmland soil remediation effect within the range of 1 (0.5-10) in the mixing volume ratio.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. The composition for removing organic pollutants from farmland soil is characterized by comprising a trivalent manganese-sodium pyrophosphate complex solution and a soybean meal extracting solution, wherein the concentration of the trivalent manganese-sodium pyrophosphate complex solution is 5-50 mmol/L, and the total concentration of active ingredients in the soybean meal extracting solution is 0.5-5 g/L.

2. The composition for removing organic pollutants from farmland soil according to claim 1, wherein the volume ratio of the trivalent manganese-sodium pyrophosphate complex solution to the soybean meal extracting solution is 1 (0.5-10).

3. The composition for removing organic pollutants from farmland soil according to claim 1 or 2, wherein the preparation method of the trivalent manganese-sodium pyrophosphate complex solution comprises the following steps:

4. The composition for removing organic pollutants from farmland soil according to claim 3, wherein the concentration of manganese dioxide in the mixed solution is 0.5-5 g/L, the concentration of sodium pyrophosphate is 0.1-1 mol/L, and the concentration of sodium sulfite is 2.5-25 mmol/L.

5. The composition for removing organic pollutants from farmland soil according to claim 3, wherein the time of the reduction + complexation reaction is 1-2 h.

6. The composition for removing organic pollutants from farmland soil according to claim 1 or 2, wherein the preparation method of the soybean meal extracting solution comprises the following steps:

7. The composition for removing organic pollutants from farmland soil according to claim 6, wherein the dosage ratio of the soybean meal to the alkali liquor is 50-500 g: 1-2L, and the concentration of the alkali liquor is 10-20 mM; the leaching temperature is 40-60 ℃, and the leaching time is 3-8 days.

8. The composition for removing organic pollutants from farmland soil according to claim 6 or 7, wherein the active ingredients in the soybean meal extracting solution comprise vanillin, apocynin and daidzein.

9. The use of the composition for removing organic pollutants from farmland soil as claimed in any one of claims 1 to 8 for treating organic pollutants in farmland polluted soil and improving organic matters in soil.

10. The application of the composition for removing the organic pollutants in the farmland soil as claimed in claim 9, wherein the mass ratio of the farmland polluted soil to the composition for removing the organic pollutants in the farmland soil is 1 (1-10).