CN110899315A - Polycyclic aromatic hydrocarbon and vanadium combined pollution soil synergistic leacheate for stone coal smelting area and application thereof - Google Patents

Abstract

A polycyclic aromatic hydrocarbon and vanadium compound polluted soil synergistic leacheate for a stone coal smelting area and application thereof are characterized in that polluted soil particles are crushed and screened, then the soil particles are placed in a soil multi-element ex-situ leaching repair device, soybean oil and amino β cyclodextrin compound leacheate is added, meanwhile, a mode of ultrasonic strengthening and heating treatment is adopted to carry out continuous ex-situ synergistic leaching, solanum nigrum is inoculated to the leached soil, a nutrient source buffer solution with the mass equal to 0.5% -2% of the soil mass is applied, artificial culture growth is carried out to complete repair, the method can simultaneously and efficiently remove organic-inorganic compound pollutants such as polycyclic aromatic hydrocarbon and vanadium in the soil through leaching, and the solanum nigrum is inoculated and exogenous nutrient substances are added, so that deep degradation of residual polycyclic aromatic hydrocarbon in the leached soil is facilitated, and rapid recovery of ecological function diversity of soil environment microorganisms after leaching is facilitated.

Description

Polycyclic aromatic hydrocarbon and vanadium combined pollution soil synergistic leacheate for stone coal smelting area and application thereof

Technical Field

The invention belongs to the technical field of remediation of polycyclic aromatic hydrocarbon and vanadium compound contaminated soil in a contaminated site of a stone coal smelting area, and particularly relates to a polycyclic aromatic hydrocarbon and vanadium compound contaminated soil synergistic leacheate for the stone coal smelting area and application thereof.

Background

Vanadium is the fifth transition metal in the crust and is also an important nonferrous metal, and is widely applied to the fields of storage batteries, aviation materials, automobile shells, national defense industry and the like. The vanadium ore resource reserves are in the first place in the world in China, and the stone coal is a poor anthracite with less carbon and low calorific value and is a low-grade multi-metal paragenetic ore. The exploitation of vanadium is usually obtained by the smelting of stone coal, but because the average value of vanadium ore in stone coal in China is poor, the distribution of stone coal mine areas is dispersed, and the exploitation smelting process lags behind and the environmental protection measures are lacked, large-area and high-toxicity vanadium contaminated soil appears in many stone coal exploitation smelting areas and the periphery in China, and the high-concentration vanadium can be accumulated in the soil for a long time and can also bring serious hidden dangers to the health of a human body through the transmission action of geochemical cycle and a food chain. A great deal of research shows that high-concentration vanadium can bring acute toxic action to the respiratory system, reproductive system, immune system and the like of a human body; meanwhile, a large amount of petroleum hydrocarbon substances are incompletely combusted in the process of smelting stone coal, and a large amount of organic pollutants, namely polycyclic aromatic hydrocarbon is input to a smelting plant area and surrounding soil. Polycyclic aromatic hydrocarbons in soil have carcinogenic, teratogenic and mutagenic 'triple-effect', polycyclic aromatic hydrocarbons and vanadium can rapidly migrate and convert on the scale of a field space region, so that the polycyclic aromatic hydrocarbons and vanadium cause obvious negative effects on the safety of ecological environment, and become 'chemical timing bombs' around people. According to the mineral reserve statistical table, the main stone coal smelting plant area of China is more than 100. Along with the taking effect and implementation of the soil pollution prevention and treatment method of the people's republic of China in 2019, 1 month and 1 day, research on restoration technology is necessary and urgent for accelerating development of polycyclic aromatic hydrocarbon and vanadium compound polluted soil generated in a stone coal smelting area. The leaching method is an important soil remediation technology, and refers to a remediation mode of washing contaminated soil with a specific leaching agent, separating soil from liquid, and then performing safe treatment on the soil and the leaching agent. The synergistic leaching remediation technology is considered to be an effective means for remediating the composite contaminated soil due to the characteristics of high remediation efficiency, short cycle, low cost and the like, however, the research and development of the leaching remediation technology for the polycyclic aromatic hydrocarbon and vanadium composite contaminated soil of the contaminated site of the stone coal smelting area are relatively less, and the research and development of the matched research and development of the deep degradation remediation technology for the polycyclic aromatic hydrocarbon residual in the leached soil and the integrated research and development of the remediation technology for the ecological function of the soil environment after remediation are relatively less, so that the research and development of the complete set of leaching-plant remediation technology for the independent intellectual property rights in China are particularly urgent.

At present, the repair technology aiming at vanadium contaminated soil mainly comprises phytoremediation, microbial remediation, physicochemical remediation and the like. Zhao Ting (Hunan agriculture university, Master's thesis, research on soil contaminated by heavy metals vanadium, titanium, molybdenum, nickel, manganese in rush's (Beijing university of science and technology, doctor's thesis, research on the effect and mechanism of remediation of vanadium-contaminated soil by endophytic bacteria-enhanced plants), LiXun (university of Chengdu's science and technology, research on screening, identification and characteristics of vanadium-resistant microorganisms), Dingxu (Harbin university of Master's thesis, research on the combined remediation of microorganisms and plants in vanadium-contaminated soil), and the like, in the academic thesis, a variety of remediation plants and functional microorganisms for vanadium-contaminated soil, and a remediation technology combining plants and microorganisms are proposed, but the methods are mainly directed to the remediation of low-medium-concentration vanadium-contaminated soil, and the plants and microorganisms are often difficult to rapidly grow or colonize on vanadium-contaminated soil in high-risk and high-toxicity coal smelting areas, the restoration technology has longer treatment period and lower restoration efficiency, and the safety recovery treatment technology of the restored plants has higher difficulty; publication No.: CN107903911A, CN109337694A, CN108480395A and CN104845628A, respectively provide a vanadium contaminated soil amendment and a preparation method thereof, a vanadium contaminated soil in-situ long-acting repairing material, a repairing method of vanadium-containing waste residue and vanadium contaminated soil, and a calcium-based liquid curing agent and a method for in-situ fixing vanadium contaminated soil thereof, all of the above methods adopt adding an adsorbing material, an immobilized stabilizing material and a chemical-biological reducing agent into vanadium contaminated soil to promote the reduction detoxification of pentavalent vanadium in soil, the reduction of effective vanadium or the fixation of total vanadium, but the vanadium is not removed out of the soil fundamentally, the repairing efficiency is not thorough, and the toxicity of low-valent vanadium is rebounded after the low-valent vanadium is oxidized again, and the added partial chemical adsorbent or immobilized agent can bring significant negative effects on the diversity of ecological functions of soil indigenous flora; publication No.: CN104774620A provides a compound modifier for vanadium-contaminated soil, a preparation method and a modification method, the method belongs to the combination of a physicochemical restoration technology and a plant restoration technology, the modifier is added into the vanadium-contaminated soil firstly, and centipede grass, reed, yellow shell grass and the like are planted to promote the growth and restoration of plants.

Aiming at the remediation of the soil polluted by the polycyclic aromatic hydrocarbon, various modes can be selected, and the remediation is mainly divided into microbial remediation, plant remediation, physicochemical remediation and the like. Wherein, the publication number: CN109929781A, CN108817054A, CN109304362A, CN103272839A, CN102433126A, CN102463254A and CN108906869A, respectively provide a strain for degrading phenanthrene and application thereof in soil remediation, a method for strengthening phytoremediation of polycyclic aromatic hydrocarbon contaminated soil by using phytohormone and a biosurfactant, a method for remedying polycyclic aromatic hydrocarbon complex contaminated soil by using a sulfate radical advanced oxidation technology, a low-temperature plasma treatment device and a method for persistent organic pollutants in soil, a natural eluent for remedying polycyclic aromatic hydrocarbon contaminated soil and a remediation method thereof, a novel electric strengthening bioremediation polycyclic aromatic hydrocarbon contaminated soil technology and process, and a contaminated soil in-situ thermal remediation system and a method by using distributed energy, but the 8 methods mainly aim at degradation, removal and abatement of single polycyclic aromatic hydrocarbon organic pollutants in soil, and do not consider the situation of polycyclic aromatic hydrocarbon and heavy metal vanadium complex contaminated soil, and the traditional bioremediation technology is not suitable for the site soil polluted by the high-concentration stone coal smelting area, and the remediation effect is difficult to be exerted in a short time. Publication No.: CN105624057A, CN101972772A and CN107470339A provide a complete product for degrading polycyclic aromatic hydrocarbon and consisting of astragalus sinicus and microbial agents and application thereof, a combined remediation method of polycyclic aromatic hydrocarbon contaminated soil, a method and a system for remediating polycyclic aromatic hydrocarbon contaminated soil by combining Fenton-like and microorganisms.

Through related literature reference and patent search, the disclosure and acceptance of the synergistic leaching-plant combined remediation method of polycyclic aromatic hydrocarbon and vanadium combined contaminated soil in the stone coal smelting area are not found, and the closest prior art to the method is a leaching agent remediation technology, and the publication number is as follows: CN106799391A provides a method and treatment equipment for restoring vanadium contaminated soil and recovering vanadium, the method firstly adopts leaching technology to restore vanadium contaminated soil, then sets up anaerobic environment, promotes the fixed reduction reaction of functional microorganisms, and strengthens the treatment and recycling of leaching waste liquid, but in the oscillating leaching link, the required time is 2-24 h, the reaction time is longer, the treatment efficiency is lower, the process amplification difficulty of the subsequent anaerobic environment is higher, and the field engineering measure maintenance process is complex. Meanwhile, the method does not develop a matching technology for recovering and improving the ecological function of the leached soil. In addition, the method does not relate to the situation that organic pollutants, namely polycyclic aromatic hydrocarbons, and inorganic heavy metal pollutants, namely vanadium, coexist and remain in the soil.

The main defects of the prior art are as follows: the method has the advantages that the single or combined technology of plants and microorganisms is difficult to treat and repair the high-concentration vanadium contaminated soil, the synergistic leaching technology for synchronously removing the polycyclic aromatic hydrocarbon and heavy metal vanadium compound pollutants in the soil is lacked, the selected chemical leaching agent is poor in environmental friendliness, the organic-inorganic pollutants are difficult to simultaneously and synchronously and efficiently elute and remove, the pollutant removal effect is not thorough, the ecological function recovery effect of the soil environment after leaching is not ideal, the research and development of related cooperative matched repair technologies are obviously followed up insufficiently, and the like, so the market application prospect of the prior art is unclear.

The main causes of defects are: in recent years, a large number of polycyclic aromatic hydrocarbon and heavy metal vanadium compound pollution sites caused by the stone coal smelting process appear, and early-stage science and technology personnel pay relatively little attention to and research and development on the polluted soil remediation technology, or pay only attention to the remediation technology of single polycyclic aromatic hydrocarbon and single vanadium polluted soil, while the attention to the synchronous removal of high-concentration polycyclic aromatic hydrocarbon and vanadium compound pollutants in the soil and the research and development of the corresponding remediation technology are relatively less; the existing remediation technology mainly aims at the original vanadium or polycyclic aromatic hydrocarbon polluted soil with relatively low concentration, and for the organic-inorganic composite polluted site soil with high concentration, the remediation effect cannot meet the remediation requirement; the existing restoration technology considers less quick restoration and remodeling of the microbial ecological function diversity of the restored soil environment. Therefore, the research and development of the environment-friendly rapid synergistic leaching and plant ecological restoration combined restoration technology has important social value and scientific significance for solving the problem of soil environment of a large number of stone coal smelting sites in China.

Disclosure of Invention

The technical problem to be solved is as follows: aiming at the defects of the prior art, the invention provides a polycyclic aromatic hydrocarbon and vanadium compound contaminated soil synergistic leacheate for a stone coal smelting area and application thereof, the method has a broad-spectrum synergistic high-efficiency removal effect on organic-inorganic compound pollutants such as total polycyclic aromatic hydrocarbon and heavy metal vanadium in contaminated soil, the residual polycyclic aromatic hydrocarbon in the soil is degraded deeply by plants after leaching thoroughly, after the remediation is finished, the ecological environment function diversity of soil indigenous flora is remarkably restored, and the method is a high-efficiency combined remediation technology with environmental friendliness.

The technical scheme is that the polycyclic aromatic hydrocarbon and vanadium compound polluted soil synergistic leacheate for the stone coal smelting area consists of soybean oil and amino β cyclodextrin, wherein the concentration of the soybean oil is 1-5 mL.L^-1Concentration of amino β CyclodextrinIs 1-10 g.L^-1。

Preferably, the soybean oil concentration is 1 mL. L^-1The concentration of amino β cyclodextrin was 1 g.L^-1。

The leacheate is applied to restoration of polycyclic aromatic hydrocarbon and vanadium compound contaminated soil in a stone coal smelting area in combination with plants.

The specific method of application is as follows: firstly, crushing and screening polluted soil particles to obtain soil particles with the particle size not more than 2 mm; then placing the soil particles in a soil multi-element ex-situ leaching remediation device, adding mixed leacheate with the use amount being 2-4 times of the volume of the polluted soil, and simultaneously carrying out continuous ex-situ synergistic leaching by adopting an ultrasonic strengthening and heating treatment mode, wherein the specific leaching method comprises the following steps: adjusting the rotating speed of the soil multi-element ex-situ leaching repair equipment to 25-50rpm, starting a heater to heat to 20 +/-2-50 +/-2 ℃, continuing for 30-60min, simultaneously starting an ultrasonic emitter with the power of 100-200kHz, continuing for 10-30min, after stirring is stopped, separating upper-layer liquid in the equipment, realizing soil-water separation on a lower-layer soil suspension system by plate-and-frame filter pressing, completing once elution repair, and repeating for 1-2 times; inoculating solanum nigrum to the eluted soil, and applying a nutrient source buffer solution which is equal to 0.5-2% of the soil in mass, wherein the nutrient source buffer solution is prepared from 30.0 g N & L^-1NH of (2)₄NO₃And 3.0 g P. L^-1K of₂HPO₄/KH₂PO₄The composition is that the pH value of the buffer solution is regulated and controlled to be 6.4 +/-0.1, and the N/P mass ratio of the nutrient source is 10: 1; and (5) repairing the artificial culture growth.

The step of inoculating the solanum nigrum to the washed soil refers to inoculating 20-50 solanum nigrum seeds to each kilogram of soil after continuous washing and repairing.

The nutrient source buffer solution is applied by 1-2 times in the planting process of the black nightshade.

The artificial culture growth time is to complete the whole repair process after culturing for 45-90 days under natural conditions.

The formula of the mixed leacheate is 1-5 mL.L^-1Soybean oil and 1-10 g.L^-1Compounding and mixing amino β cyclodextrin ester, adjusting the rotating speed of the soil multielement ectopic leaching repair equipment to 50rpm,starting a heater to heat to 50 +/-2 ℃, continuing for 60min, simultaneously starting an ultrasonic emitter with the power of 200kHz, continuing for 30min, separating upper-layer liquid in the equipment after stirring is stopped, realizing soil-water separation on a lower-layer soil suspension system by plate-and-frame filter pressing, and repeating for 2 times to obtain the highest removal rate of chromium in the polluted soil; then 50 solanum nigrum seeds are inoculated to the washed soil, and a nutrient source buffer solution which is equal to 2 percent of the soil mass is applied in 2 times in 90 days.

At the moment, the restoration degree of the ecological function diversity of the soil microorganisms after leaching is the most obvious.

The invention has the working principle that 1, soybean oil is vegetable oil extracted from soybean, more than 80-90 percent of the soybean oil is unsaturated fatty acid and has extremely strong dissolving capacity for organic pollutants such as nonpolar polycyclic aromatic hydrocarbon and the like, 2, the soybean oil has density smaller than water and is immiscible with water, so in a slurry stirring system, the soybean oil can be deeply stirred and mixed with soil particles, high dispersion of an oil phase medium is realized, and full contact between soybean oil tiny oil drops and the soil particles is strengthened, so that polycyclic aromatic hydrocarbon in the soil is dissolved and coated, the polar barrier effect of the water can also reduce adsorption residue of the soybean oil drops on the soil after leaching is finished, a small amount of soybean oil drops remained in the soil after leaching can be rapidly and naturally degraded, 3, β cyclodextrin is a general name of a series of cyclic oligosaccharides generated by amylose under the action of glucosyltransferase generated by bacillus and has a conical hollow cylinder three-dimensional cyclic structure, 4, amino- β -cyclodextrin is a green synthetic aminated derivative of β cyclodextrin, has the outer edge characteristics of water, hydrophobic inner cavity and has a higher solubility than 2.18 g/5395₂O, 20C, amino β Cyclodextrin:>200g /L H₂o, 20C), can more effectively promote desorption and release of heavy metal vanadium ions and compounds from soil solid phase to water phase, 5, on one hand, affinity adsorption and directional wrapping of the heavy metal vanadium ions and compounds are strengthened in the soil water phase due to amino- β -cyclodextrin through self amino functional groups, and on the other hand, micelle hydrophobic core distribution effect of amino- β -cyclodextrin can also be realized on soilThe method comprises the steps of 1, solubilizing organic pollutants polycyclic aromatic hydrocarbons in soil, effectively promoting desorption and release of the polycyclic aromatic hydrocarbons and chromium from soil particle solid phase to water phase, improving elution removal rate of the composite pollutants, 6, jointly using soybean oil and amino- β -cyclodextrin for compound elution, playing a role of 'bridge' of solubilizing and transferring the organic pollutants polycyclic aromatic hydrocarbons in a compound elution system by the amino- β -cyclodextrin, promoting soybean oil to become 'confluence' of adsorption and complex wrapping of the organic pollutants polycyclic aromatic hydrocarbons, synchronously achieving the purpose of efficiently removing the heavy metal vanadium, and finally generating an effect of synergistically eluting and removing the polycyclic aromatic hydrocarbons and vanadium in the soil of the stone coal smelting polluted site by more than a single reagent on the whole, 7, heating treatment can remarkably accelerate elution reaction process, cavitation effect and disturbance effect of ultrasonic strengthening treatment can remarkably enhance pollutant mass transfer process, the two effects can be integrated to generate synergistic effect which is more than single treatment, 8, black nightshade has strong capability of enduring various composite heavy metal pollutants in the soil, can degrade a small amount of residual aromatic hydrocarbons in the soil, and can quickly restore ecological environment of the black nightshade, and black nightshade can be used as a synergistic washing solution for quickly repairing the soil, the soil is favorable for the root system, the root system of a synergistic and a synergistic effect of a synergistic organic pollutant of a synergistic leaching technology for recovering the black nightshade-alkaline environment, a synergistic leaching technology for recovering the black nightshade soil, a synergistic and a synergistic effect of an inorganic pollutant-alkaline environment, a synergistic leaching technology for recovering the black nightshade soil, a synergistic effect of a synergistic leaching and a synergistic effect of a large-alkaline environment, and a large-alkaline environment, and a large-alkaline.

Has the advantages that: 1. the method can synchronously and efficiently remove high-concentration organic pollutants polycyclic aromatic hydrocarbons and inorganic heavy metal pollutants vanadium in the field soil by leaching; 2. the continuous elution repair efficiency is high, the operation is simple and convenient, the period is short, the broad spectrum is high, and the popularization is easy; 3. the two kinds of eluting agents have low cost, are environment-friendly, can be naturally degraded and do not cause secondary pollution to soil; 4. the inoculation of the nightshade and the addition of exogenous nutrient substances are beneficial to the deep degradation of residual polycyclic aromatic hydrocarbons in the soil after leaching, and the diversity of the ecological functions of indigenous microorganisms in the soil is quickly recovered. The method has wide application prospect for the remediation work of the soil of the polycyclic aromatic hydrocarbon and vanadium compound polluted site in a large number of stone coal smelting areas in China.

Drawings

FIG. 1 is a schematic diagram of a dedicated leaching apparatus;

FIG. 2 shows the technical scheme of the invention, when the eluent has the components of 1 mL.L^-1Soybean oil and 1 g.L^-1A verification chart of synchronous leaching removal effect of polycyclic aromatic hydrocarbon and vanadium in soil of a polluted site of a certain stone coal mining area in Hede city, Hede, Hunan province when amino β is cyclodextrin;

FIG. 3 shows that when the eluent has a composition of 5 mL.L^-1Soybean oil and 5 g.L^-1A verification chart of synchronous leaching removal effect of polycyclic aromatic hydrocarbon and vanadium in soil of a certain stone coal mining area in Quzhou city, Zhejiang province when amino β cyclodextrin is used;

FIG. 4 shows that when the eluent has a composition of 5 mL.L^-1Soybean oil and 10 g.L^-1A verification chart of synchronous leaching removal effect of polycyclic aromatic hydrocarbon and vanadium in soil of a polluted site of a certain stone coal mine area in Panzhihua city, Sichuan province when amino β cyclodextrin is used;

Detailed Description

The following detailed description does not limit the technical solutions of the present invention in any way, and all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the scope of the present invention.

The leacheate used was: 1-5 mL. L^-1Soybean oil and 1-10 g.L^-1Amino β and cyclodextrin.

The special leaching equipment (figure 1, CN 201310092591.5) comprises a stirring device, a leaching agent injection device, a leaching agent recovery device 5, an ultrasonic generator and a heater 8; the stirring device comprises a stirring cavity 1, a spiral stirrer 2 and a stainless steel pneumatic ball valve 7; a feed inlet 6 is arranged on the stirring cavity, the spiral stirrer 2 is arranged in the stirring cavity 1 and driven by a motor 9, and the stainless steel pneumatic ball valve 7 is arranged below the end face of the stirring cavity far away from the motor; the eluent injection device comprises at least two eluent injectors, including a first eluent injector 3 and a second eluent injector 4, wherein at least one eluent injector is coated with a heat-insulating material, and the eluent injection device is arranged at the top of the stirring cavity; the eluent recovery device 5 comprises a recovery pipe and a recovery pump, wherein one end of the recovery pipe is connected with the recovery pump, and the other end of the recovery pipe is movably connected to the stirring cavity; the heater 8 and the ultrasonic generator are distributed on the wall of the stirring cavity. The section of the stirring cavity is semi-elliptical, a fender covering the cavity is arranged above the stirring cavity, and the feed inlet 6, the outlet of the eluent injection device and the inlet of the eluent recovery device 5 are arranged on the fender. The stirring blade of the spiral stirrer is coaxial with the motor, the diameter of the stirring blade is 2/3 of the height of the stirring cavity, and the operation speed of the blade is 25-50 rpm. The bottom edge of the stirring cavity takes the end close to the stainless steel pneumatic ball valve as a vertex and forms an inclination angle of 4 degrees with the horizontal line, so that clean soil after leaching and repairing is smoothly discharged. The connection parts of the motor, the stainless steel pneumatic ball valve, the mud pump and the stirring cavity are sealed. The heater 8 comprises an electric heating device and a heat insulation material, the electric heating device and the heat insulation material cover the outer wall of the stirring cavity, and the heating temperature of the stirring cavity is controlled to be 20 +/-2-50 +/-2 ℃. The ultrasonic transmitter comprises a group of ultrasonic vibration heads, the ultrasonic vibration heads are uniformly distributed on the inner wall of the stirring cavity, and the power of each ultrasonic vibration head is 2.5-5 kW. The stirring cavity 1 is also provided with an ozone tube and a thermocouple temperature measuring device. The system also comprises a touch screen type artificial intelligence electronic operation platform which is connected with all components for controlling the repair equipment.

The method for repairing the chromium slag left site soil by using the equipment comprises the following repairing steps: a. soil pretreatment: firstly, screening the soil of the polluted site to the particle size of about 2 mm; b. setting a repair system: adding an eluting agent with the volume 2-4 times that of the soil into the stirrer, wherein the volume ratio of the volume of the stirring cavity to the soil-eluting agent mixed muddy water is not less than 1.25; c. setting repair operation parameters: the spiral stirring speed is 25-50rpm, the temperature is 20 +/-2-50 +/-2 ℃, and the holding time is 60 min; starting an ultrasonic transmitter for 30 min; d. and (3) finishing elution: after the equipment runs for 60min, stopping stirring and standing, recovering the eluent on the upper layer in the stirring cavity by using an eluent recoverer, discharging the soil on the lower layer through a stainless steel pneumatic ball valve, and realizing the separation of soil and water by plate and frame filter pressing to finish elution repair.

Example 1:

for the total polycyclic aromatic hydrocarbon concentration of more than 250 mg kg^-1And less than 1000 mg kg^-1The total vanadium concentration is more than 100 mgkg^-1And less than 500 mg kg^-1The soil of the polluted site of the stone coal mining area is as follows:

the soil to be tested was collected from a contaminated site of a certain stone coal mine area in Hede City, Hunan province. And (4) air-drying the soil sample, picking out impurities, and sieving by using a 10-mesh sieve for later use. The basic physical and chemical properties of the soil are that the pH value is 7.8, and the organic matter content is 14.8 g kg^-11.5 g kg of total nitrogen^-136.7 mg kg of available nitrogen^-10.4 g kg of total phosphorus^-128.4 mg kg of available phosphorus^-1. The soil machinery composition contained 17.2 wt.% sand, 63.3 wt.% soil, 19.5 wt.% slime. The background pollution concentration of total polycyclic aromatic hydrocarbon, total vanadium and pentavalent vanadium in the soil is 887.4 plus or minus 34.4 mg kg^-1、454.6 ± 35.1 mg kg^-1And 166.2. + -. 8.2 mg kg^-1. Before leaching, the polluted soil is firstly air-dried and sieved to remove the difficultly-broken substances such as stones with larger particle size and plant roots in the soil, then soil particles with the particle size of less than 2mm are poured into the soil multi-element ex-situ leaching remediation equipment (figure 1) (CN 201310092591.5), and then mixed leachate with the volume of 2 times that of the soil is added, wherein the component of the leachate is 1 mL.L^-1Soybean oil and 1 g.L^-1Amino β cyclodextrin and deionized water as solvent, adjusting the rotation speed of the soil multi-element ectopic leaching repair equipment to 50rpm, starting a heater to 50 +/-2 ℃, keeping for 60min, simultaneously starting an ultrasonic emitter with the power of 200kHz, keeping for 10 min, stopping stirring, and standingSeparating the middle-upper layer liquid in the leaching repair equipment, and performing plate-frame filter pressing on the lower layer soil suspension system to realize soil-water separation to finish the repair of the leaching link; as can be seen from FIG. 2, the removal rates of the total amount of polycyclic aromatic hydrocarbons, the total vanadium and the pentavalent vanadium in the soil after 1 leaching are respectively 95.8 +/-2.1%, 86.7 +/-5.2% and 98.7 +/-3.4% through detection. After leaching is finished, the concentration of the polycyclic aromatic hydrocarbon in the residual soil meets the related requirements of national soil pollution risk control standard (trial) for soil environment quality construction land GB 36600-2018. The concentration of the total vanadium and the pentavalent vanadium in the residual soil is lower than the average background value of the vanadium content in the soil in China.

Reference is made to the compounding concentration of other soybean oil and amino β cyclodextrin, such as 5 g.L^-1Soybean oil and 10 g.L^-1The removal rates of total polycyclic aromatic hydrocarbon, total vanadium and pentavalent vanadium in the soil after 1 leaching are respectively 78.8 +/-6.7%, 72.5 +/-4.3% and 77.2 +/-8.1% after 1 leaching by using amino β cyclodextrin, which indicates that the concentration of the total polycyclic aromatic hydrocarbon is more than 250 mgkg-1 and less than 1000 mg kg-1 and the concentration of the total vanadium is more than 100 mg kg^-1And less than 500 mg kg^-1The soil of the stone coal mining area polluted site cannot linearly increase the removal efficiency of the composite pollutants in the soil by simply increasing the compound concentration of the soybean oil and the amino β cyclodextrin, the viscosity of the system is increased due to the combination of the concentration of the eluent, the mass transfer and the migration of the composite pollutants in the soil are not facilitated, and the cost investment of the eluent is increased.

Inoculating 20 Solanum nigrum seeds to each kilogram of soil after washing, and simultaneously adding the fertilizer with the mass equivalent to 0.5 percent of the soil (30.0 g N L) on the 1 st and 45 th days in the plant growth process^-1NH of (2)₄NO₃And 3.0 g of PL^-1K of₂HPO₄/KH₂PO₄The pH value of the buffer solution is regulated and controlled to be 6.8 +/-0.2, the mass ratio of the N/P nutrient source is 10:1, the culture is carried out for 90 days under natural conditions, and the concentration of the residual state total amount of polycyclic aromatic hydrocarbon in the soil is found to be 37.3 +/-2.5 mgkg from the concentration just leached^-1Reduced to 17.7 + -5.1 mg kg^-1The planting of the black nightshade can further deeply degrade the total amount of polycyclic aromatic hydrocarbon in the residual state in the soil after washing; and also send outAt the moment, the indexes of the ecological diversity of the soil environment microorganisms, namely the AWCD index, the Shannon-Weaver index and the Simpson index reach 3.3 +/-0.3, 2.7 +/-0.2 and 2.9 +/-0.2 after restoration, and are obviously increased by (2.3 +/-0.3, 2.2 +/-0.2 and 1.5 +/-0.3) compared with the corresponding indexes of the original polluted soil (2.3 +/-0.3, 2.2 +/-0.2 and 1.5 +/-0.3)p<0.05), which shows that the ecological diversity of the soil indigenous flora environment microorganisms is remarkably restored after the combined remediation technology is applied.

Referring to the comparative experiment, the AWCD index, Shannon-Weaver index and Simpson index failed to show significant increases after 90 days of culture with the addition of nutrient buffer equivalent to <0.5% of soil mass; after 90 days of culture with the addition of a nutrient buffer equivalent to > 0% of the mass of the soil (e.g. 1%), the AWCD index, Shannon-Weaver index and Simpson index did not show significant differences from the relevant diversity index obtained with the addition of a nutrient buffer equivalent to 0.5% of the mass of the soil. Therefore, adding a nutrient buffer solution which is equal to 0.5% of the soil mass to the soil after leaching is a preferable method which can achieve both ecological function recovery efficiency and low cost.

Example 2:

for the total polycyclic aromatic hydrocarbon concentration of more than 1000 mg kg^-1The total vanadium concentration is more than 500 mg kg^-1And less than 1000 mgkg^-1The soil of the polluted site of the stone coal mining area is as follows:

the tested soil is collected from a polluted site of a certain stone coal mining area in Zhejiang province, Quzhou city. And (4) air-drying the soil sample, picking out impurities, and sieving by using a 10-mesh sieve for later use. The basic physical and chemical properties of the soil are that the pH value is 5.9, and the organic matter content is 27.7 g kg^-11.8 g kg of total nitrogen^-131.9 mg kg of available nitrogen^-10.2 g kg of total phosphorus^-119.5 mg kg of available phosphorus^-1. The soil mechanical composition was 12.8 wt.% sand, 68.7 wt.% soil, 18.5 wt.% slime. The background pollution concentration of the total amount of polycyclic aromatic hydrocarbon, the total amount of vanadium and the pentavalent vanadium in the soil is 1271.3 +/-94.3 mg kg^-1、927.8 ± 62.4 mg kg^-1And 352.4 + -22.4 mg kg^-1. Before leaching, the polluted soil is firstly air-dried and sieved to remove the difficultly-broken substances such as stones with larger particle size, plant roots and the like in the soil, and then soil particles with particle size of less than 2mm are poured into the soilIn the soil multi-element ectopic leaching remediation equipment (figure 1) (CN 201310092591.5), mixed leacheate with the volume 2 times that of the soil is added, and the component of the leacheate is 5 mL & L^-1Soybean oil and 5 g.L^-1The method comprises the steps of preparing amino β cyclodextrin and deionized water as a solvent, adjusting the rotating speed of soil multielement ectopic repair equipment to 25 rpm, starting a heater to 25 +/-2 ℃, continuing for 15 min, simultaneously starting an ultrasonic emitter with the power of 100 kHz, continuing for 30min, stopping stirring, standing, separating middle and upper layer liquid in the elution repair equipment, separating soil and water in a lower layer soil suspension system by plate and frame filter pressing to complete the repair of an elution link, and finding that the removal rates of total polycyclic aromatic hydrocarbon, total vanadium and pentavalent vanadium in soil after 1 leaching are respectively 98.1 +/-5.2%, 92.2 +/-2.6% and 88.2 +/-7.3% through detection.

Reference is made to the compounding concentration of other soybean oil and amino β cyclodextrin, such as 5 g.L^-1Soybean oil and 10 g.L^-1The amino β cyclodextrin shows that the removal rates of the total polycyclic aromatic hydrocarbon, the total vanadium and the pentavalent vanadium in the soil after 1 leaching are respectively 83.4 +/-5.2%, 79.6 +/-7.1% and 83.5 +/-4.3% after 1 leaching, which indicates that the concentration of the total polycyclic aromatic hydrocarbon is more than 1000 mgkg^-1The total vanadium concentration is more than 500 mg kg^-1And less than 1000 mg kg^-1The soil of the stone coal mining area polluted site cannot linearly increase the removal efficiency of the composite pollutants in the soil by simply increasing the compound concentration of the soybean oil and the amino β cyclodextrin, the viscosity of the system is increased due to the combination of the concentration of the eluent, the mass transfer and the migration of the composite pollutants in the soil are not facilitated, and the cost investment of the eluent is increased.

Inoculating 50 Solanum nigrum seeds to each kilogram of soil after washing, and simultaneously adding 1% of the soil (30.0 g N L) on the 1 st and 45 th days in the plant growth process^-1NH of (2)₄NO₃And 3.0 g of PL^-1K of₂HPO₄/KH₂PO₄The pH value of the buffer solution is regulated and controlled to be 6.8 +/-0.2, the mass ratio of the N/P nutrient source is 10:1, the culture is carried out for 90 days under natural conditions, and the concentration of the residual state total amount of polycyclic aromatic hydrocarbon in the soil is found to be 24.2 +/-4.3 mgkg from the just washed concentration^-1Reduced to 14.6 + -1.6 mg kg^-1The planting of the black nightshade can further deeply degrade the total amount of polycyclic aromatic hydrocarbon in the residual state in the soil after washing; and the indexes of the ecological diversity of the soil environment microorganisms, namely the AWCD index, the Shannon-Weaver index and the Simpson index reach 2.9 +/-0.2, 3.4 +/-0.3 and 2.3 +/-0.1 after restoration, and are obviously increased by (1.6 +/-0.1, 2.3 +/-0.2 and 1.4 +/-0.3) compared with the corresponding indexes of the original polluted soil (1.6 +/-0.1, 2.3 +/-0.2 and 1.4 +/-0.3)p<0.05), which shows that the ecological diversity of the soil indigenous flora environment microorganisms is remarkably restored after the combined remediation technology is applied.

Referring to the comparative experiment, the AWCD index, Shannon-Weaver index and Simpson index failed to show significant increase after 90 days of culture with addition of nutrient buffer equivalent to <1% of soil mass; after 90 days of culture with the addition of a nutrient buffer equivalent to >1% of the mass of the soil (e.g. at 2%), the AWCD index, Shannon-Weaver index and Simpson index did not show significant differences from the relevant diversity index obtained with the addition of a nutrient buffer equivalent to 1% of the mass of the soil. Therefore, adding a nutrient buffer solution which is equal to 1% of the soil mass to the soil after leaching is a preferable method which can achieve both ecological function recovery efficiency and low cost.

Example 3:

for the total polycyclic aromatic hydrocarbon concentration of more than 1000 mg kg^-1The total vanadium concentration is more than 1000 mg kg^-1The soil of the polluted site of the stone coal mining area is as follows:

the soil to be tested was collected from a contaminated site of a certain stone coal mining area in Panzhihua City, Sichuan province. And (4) air-drying the soil sample, picking out impurities, and sieving by using a 10-mesh sieve for later use. The basic physical and chemical properties of the soil are that the pH value is 8.2, and the organic matter content is 24.7 g kg^-12.7 g kg of total nitrogen^-152.3 mg kg of available nitrogen^-10.1 g kg of total phosphorus^-111.6 mg kg of available phosphorus^-1. The soil mechanical composition was 18.4 wt.% sand66.2 wt.% soil grains, 15.4 wt.% clay grains. The background pollution concentrations of total polycyclic aromatic hydrocarbon, total vanadium and pentavalent vanadium in the soil are 1335.2 plus or minus 201.5 mg kg respectively^-1、1588.4 ± 229.6 mg kg^-1And 580.1 + -64.2 mg kg^-1. Before leaching, the polluted soil is firstly air-dried and sieved to remove the difficultly-broken substances such as stones with larger particle size and plant roots in the soil, then soil particles with the particle size of less than 2mm are poured into the soil multi-element ex-situ leaching remediation equipment (figure 1) (CN 201310092591.5), and then mixed leachate with the volume of 4 times that of the soil is added, wherein the component of the leachate is 5 mL.L^-1Soybean oil and 10 g.L^-1The method comprises the steps of carrying out extraction treatment on soil, carrying out extraction treatment on soil suspension, carrying out extraction treatment on the soil, carrying out extraction treatment on the extracted soil, and carrying out extraction treatment on the extracted soil for 2 times, wherein the extraction treatment is carried out by using amino β cyclodextrin and deionized water as a solvent, regulating the rotation speed of a soil multi-element ex-situ remediation device to be 25 rpm, starting a heater to be 25 +/-2 ℃, continuing for 30min, starting an ultrasonic emission instrument with the power of 200kHz, stopping stirring and standing, separating middle and upper layer liquid in the elution remediation device, and carrying out the extraction treatment on the lower layer soil suspension system by using plate and plate.

Reference is made to the combination concentration of other soybean oil and amino β cyclodextrin, such as 10 g.L^-1Soybean oil and 20 g.L^-1The amino β cyclodextrin shows that the removal rates of the total polycyclic aromatic hydrocarbon, the total vanadium and the pentavalent vanadium in the soil after 1 leaching are respectively 85.1 +/-2.2%, 84.2 +/-2.4% and 86.3 +/-3.3% after 1 leaching, which indicates that the concentration of the total polycyclic aromatic hydrocarbon is more than 1000 mgkg^-1The total vanadium concentration is more than 1000 mg kg^-1The soil of the polluted site of the stone coal mining area can not linearly increase the removal efficiency of the compound pollutants in the soil by simply increasing the compound concentration of the soybean oil and the amino β cyclodextrin, and the system viscosity is increased and the reverse effect is realized by combining too high eluent concentrationBut not beneficial to the mass transfer and migration of the composite pollutants in the soil, and increases the cost investment of the eluent.

Inoculating 50 Solanum nigrum seeds to each kilogram of soil after two times of leaching, and simultaneously adding the seeds which are equal to 2 percent of the soil mass (30.0 g of N L) on the 1 st day and the 45 th day respectively in the plant growth process^-1NH of (2)₄NO₃And 3.0 g of PL^-1K of₂HPO₄/KH₂PO₄The pH value of the buffer solution is regulated and controlled to be 6.8 +/-0.2, the mass ratio of the N/P nutrient source is 10:1, the culture is carried out for 60 days under natural conditions, and the concentration of the residual state total amount of polycyclic aromatic hydrocarbon in the soil is found to be 20.1 +/-2.3 mg kg after the two times of leaching^-1Reduced to 13.2 + -0.6 mg kg^-1The planting of the black nightshade can further deeply degrade the total amount of polycyclic aromatic hydrocarbon in the residual state in the soil after washing; and the indexes of the ecological diversity of the soil environment microorganisms, namely the AWCD index, the Shannon-Weaver index and the Simpson index reach 3.1 +/-0.4, 3.2 +/-0.1 and 2.9 +/-0.4 after restoration, and are obviously increased (p is obviously increased) compared with the corresponding indexes (2.1 +/-0.3, 2.2 +/-0.4 and 1.6 +/-0.5) of the original polluted soil<0.05), which indicates that the ecological diversity of the microorganisms in the environment of the indigenous flora of the polluted soil is remarkably restored.

Referring to the comparative experiment, the AWCD index, Shannon-Weaver index and Simpson index failed to show significant increases after 90 days of culture with the addition of nutrient buffer equivalent to <2% of soil mass; after 90 days of culture with the addition of a nutrient buffer equivalent to >2% of the mass of the soil (e.g. at 3%), the AWCD index, Shannon-Weaver index and Simpson index did not show significant differences from the relevant diversity index obtained with the addition of a nutrient buffer equivalent to 2% of the mass of the soil. Therefore, adding a nutrient buffer solution which is equal to 2% of the soil mass to the soil after leaching is a preferable method which can achieve both ecological function recovery efficiency and low cost.

The result shows that the synergistic leaching-plant combined remediation method for remediating the polycyclic aromatic hydrocarbon and vanadium composite contaminated site soil in the high-concentration stone coal mine area has the advantages of high synchronous organic-inorganic pollutant removal efficiency, thorough plant deep degradation and excellent environmental friendliness, and is a site soil remediation technology with good application prospect.

Claims (8)

1. The polycyclic aromatic hydrocarbon and vanadium compound polluted soil synergistic leacheate for the stone coal smelting area is characterized by comprising soybean oil and amino β cyclodextrin, wherein the concentration of the soybean oil is 1-5 mL.L^-1The concentration of amino β cyclodextrin is 1-10 g.L^-1。

2. The polycyclic aromatic hydrocarbon and vanadium combined polluted soil synergistic leacheate for stone coal smelting zone according to claim 1, wherein the concentration of soybean oil is 1 mL-L^-1The concentration of amino β cyclodextrin was 1 g.L^-1。

3. The use of the leacheate of claim 1 or 2 in combination with plants for remediation of polycyclic aromatic hydrocarbon and vanadium combined contaminated soil in a stone coal smelting area.

4. Use according to claim 3, characterized in that: firstly, crushing and screening polluted soil particles to obtain soil particles with the particle size not more than 2 mm; then placing the soil particles in a soil multi-element ex-situ leaching remediation device, adding mixed leacheate with the use amount being 2-4 times of the volume of the polluted soil, and simultaneously carrying out continuous ex-situ synergistic leaching by adopting an ultrasonic strengthening and heating treatment mode, wherein the specific leaching method comprises the following steps: adjusting the rotating speed of the soil multi-element ex-situ leaching repair equipment to 25-50rpm, starting a heater to heat to 20 +/-2-50 +/-2 ℃, continuing for 30-60min, simultaneously starting an ultrasonic emitter with the power of 100-200kHz, continuing for 10-30min, after stirring is stopped, separating upper-layer liquid in the equipment, realizing soil-water separation on a lower-layer soil suspension system by plate-and-frame filter pressing, completing once elution repair, and repeating for 1-2 times; inoculating solanum nigrum to the eluted soil, and applying a nutrient source buffer solution which is equal to 0.5-2% of the soil in mass, wherein the nutrient source buffer solution is prepared from 30.0 g N & L^-1NH of (2)₄NO₃And 3.0 g P. L^-1K of₂HPO₄/KH₂PO₄The composition is that the pH value of the buffer solution is regulated and controlled to be 6.4 +/-0.1, and the N/P mass ratio of the nutrient source is 10: 1; artificial cultureAnd (5) repairing after growth is completed.

5. The use according to claim 3, wherein the inoculation of solanum nigrum to the washed soil is 20-50 solanum nigrum seeds per kilogram of soil after continuous washing and remediation.

6. The use according to claim 3, characterized in that the application of the nutrient source buffer is carried out in 1-2 applications during the black nightshade planting.

7. The use of claim 3, wherein the artificial culture is grown for 45-90 days under natural conditions to complete the overall repair process.

8. Use according to claim 3, characterized in that the mixed leacheate formulation is 1-5 mL-L^-1Soybean oil and 1-10 g.L^-1Compounding and mixing amino β cyclodextrin ester, adjusting the rotating speed of soil multielement ectopic leaching repair equipment to 50rpm, starting a heater to heat to 50 +/-2 ℃, continuing for 60min, simultaneously starting an ultrasonic emitter with the power of 200kHz, continuing for 30min, separating upper-layer liquid in the equipment after stirring is stopped, realizing soil-water separation on a lower-layer soil suspension system by plate-and-frame filter pressing, repeating for 2 times, obtaining the highest removal rate of chromium in the polluted soil, inoculating 50 solanum nigrum seeds to the leached soil, and applying a nutrient source buffer solution with the mass equal to 2% of the soil in 2 times within 90 days.

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