CN112642851B - Heavy metal contaminated soil purification method - Google Patents
Heavy metal contaminated soil purification method Download PDFInfo
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- CN112642851B CN112642851B CN202011337679.5A CN202011337679A CN112642851B CN 112642851 B CN112642851 B CN 112642851B CN 202011337679 A CN202011337679 A CN 202011337679A CN 112642851 B CN112642851 B CN 112642851B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/08—Reclamation of contaminated soil chemically
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K17/00—Soil-conditioning materials or soil-stabilising materials
- C09K17/40—Soil-conditioning materials or soil-stabilising materials containing mixtures of inorganic and organic compounds
Abstract
The invention discloses a method for purifying heavy metal polluted soil, which comprises the following steps: firstly, adding an acid solution into the soil polluted by heavy metals, carrying out acidification treatment, and drying to obtain acidified soil; adding a soil improvement filler, deionized water and dithiocarbamate into the acidified soil, and stirring to obtain a mixed solution; and finally, adding a sodium carbonate solution and a lime nitrate solution into the mixed solution for solidification treatment, thus completing soil purification. The invention provides a soil purification method with strong infiltration capacity, purification capacity, long service life and reasonable cost; after purification, the heavy metal content in the soil is obviously reduced, and no solid waste and no secondary pollution are generated in the purification process; the method has wide applicability and operability.
Description
Technical Field
The invention belongs to the technical field of soil purification, and particularly relates to a heavy metal polluted soil purification method.
Background
The soil not only provides mechanical support capability for plant growth, but also provides fertility factors such as water, fertilizer, gas, heat and the like required by the growth and development of the plant. In recent years, as the population is rapidly increased and the industry is rapidly developed, solid waste is continuously piled and dumped to the surface of soil, harmful waste water is continuously permeated into the soil, and waste gas discharged by automobiles, harmful gas and floating dust in the atmosphere are continuously fallen in the soil along with rainwater. The improvement of the level of agricultural chemistry causes a large amount of chemical fertilizers and pesticides to scatter into the environment, so that the soil is polluted more and more, the degree of the pollution is more and more serious, and the pollution area is continuously enlarged under the influence of water and soil loss, wind erosion and the like. Soil pollutants are divided into two categories, inorganic and organic, according to the nature of the pollutants: the inorganic substances mainly comprise heavy metals such as mercury, chromium, lead, copper and zinc and non-metals such as arsenic and selenium; the organic substances mainly comprise phenols, organic pesticides, oils, benzopyrenes, detergents and the like. These chemical pollutants are carried into the soil and accumulated, mainly by sewage, waste gases, solid wastes, pesticides and fertilizers. The soil pollution causes the yield reduction of crops and the quality reduction of agricultural products, pollutes underground water and surface water, and is harmful to human health; at present, chemical modifiers are mostly applied to convert heavy metals into insoluble compounds and reduce the absorption of crops. But the use cost of the synthetic modifier is higher, the intermediate product has secondary pollution, or the influence on organisms and ecosystems is not clear; in addition, the modifier has high use cost and is difficult to popularize generally.
Disclosure of Invention
The invention aims to provide a method for purifying soil polluted by heavy metal, which solves the problems of single purification effect and poor purification capability of the soil in the prior art.
The technical scheme adopted by the invention is that the method for purifying the soil polluted by the heavy metal is implemented according to the following steps:
step 1, adding an acid solution into soil polluted by heavy metals, carrying out acidification treatment, and then naturally drying to obtain acidified soil;
step 2, adding soil improvement filler, deionized water and dithiocarbamate into the acidified soil, and stirring for 1-2 hours to obtain a mixed solution;
and 3, adding a sodium carbonate solution and a lime nitrate solution into the mixed solution for solidification treatment, and completing soil purification.
The present invention is also characterized in that,
in the step 1, the acid solution is a hydrochloric acid solution or a nitric acid solution; the acidification treatment time is 5-10 h.
In the step 2, the mass ratio of the soil improvement filler to the deionized water to the dithiocarbamate is 10: 80-200: 5.
in the step 2, the preparation method of the soil improvement filler comprises the following steps:
step 2.1, mixing sponge iron, titanium dioxide, potassium permanganate and water, and then carrying out condensation reflux reaction to obtain a reaction solution;
and 2.2, mixing the reaction liquid obtained in the step 2.1 with wood chips and a modifier, adjusting the pH of the reaction liquid to 8.0-9.5 by using an iron hydroxide solution, then putting the reaction liquid into a reaction kettle with a polyethylene tetrafluoro lining for hydrothermal reaction, washing the reaction liquid to be neutral by using deionized water after the reaction is finished, and drying to obtain the soil improvement filler.
In the step 2.1, the reflux reaction temperature is 150 ℃ and 180 ℃, and the reflux reaction time is 2-4 h.
In the step 2.2, the modifying agent is one or two of fly ash, green zeolite, blast furnace slag and zeolite.
In the step 2.2, the hydrothermal reaction temperature is 110-140 ℃, and the hydrothermal reaction time is 5-8 h.
In the step 3, the mass ratio of the mixed solution, the sodium carbonate solution and the lime nitrate solution is 150: 8: 10-25; the curing time is 4-8 h; the mass concentration of the lime hydrate solution and the sodium carbonate solution is 5-8 percent.
The beneficial effect of the invention is that,
the soil purification method of the invention makes up the defects of permeability, purification capacity and the like of the traditional purification method, and provides the soil purification method which has stronger infiltration capacity and purification capacity, long service life and reasonable cost; after purification, the heavy metal content in the soil is obviously reduced, and no solid waste and no secondary pollution are generated in the purification process; the method has wide applicability and operability.
Detailed Description
The present invention will be described in detail with reference to the following embodiments.
The invention relates to a method for purifying heavy metal contaminated soil, which is implemented according to the following steps:
step 1, adding an acid solution into soil polluted by heavy metals, carrying out acidification treatment, and then naturally drying to obtain acidified soil;
the acid solution is hydrochloric acid solution or nitric acid solution;
the acidification treatment time is 5-10 h;
the mass ratio of the soil to the acid solution is 100: 1-1.5;
step 2, adding soil improvement filler, deionized water and dithiocarbamate into the acidified soil, and stirring for 1-2 hours to obtain a mixed solution;
the mass ratio of the soil improvement filler to the deionized water to the dithiocarbamate is 10: 80-200: 5;
the preparation method of the soil improvement filler comprises the following steps:
step 2.1, mixing sponge iron, titanium dioxide, potassium permanganate and water, and then carrying out condensation reflux reaction to obtain a reaction solution;
the reflux reaction temperature is 150 ℃ and 180 ℃, and the reflux reaction time is 2-4 h;
the mass ratio of sponge iron to titanium dioxide to potassium permanganate to water is 15: 5: 1-2: 100-;
step 2.2, mixing the reaction liquid obtained in the step 2.1 with wood chips and a modifier, adjusting the pH of the reaction liquid to 8.0-9.5 by using an iron hydroxide solution, then putting the reaction liquid into a reaction kettle with a polyethylene tetrafluoro lining for hydrothermal reaction, washing the reaction liquid to be neutral by using deionized water after the reaction is finished, and drying to obtain a soil improvement filler;
the mass ratio of the reaction liquid to the wood chips to the modifier is 80: 10: 2-9;
the modifier is one or two of fly ash, green zeolite, blast furnace slag and zeolite;
the mass concentration of the ferric hydroxide solution is 10-20%;
the hydrothermal reaction temperature is 110-140 ℃, and the hydrothermal reaction time is 5-8 h;
step 3, adding a sodium carbonate solution and a lime nitrate solution into the mixed solution for solidification treatment, and then completing soil purification;
the mass ratio of the mixed solution to the sodium carbonate solution to the lime nitrate solution is 150: 8: 10-25;
the curing time is 4-8 h;
the mass concentration of the lime-nitrate solution and the mass concentration of the sodium carbonate solution are both 5 to 8 percent.
According to the soil improvement filler disclosed by the invention, the TP and Zn removal effect is better by adding the sponge iron; the TN removal effect is better by adding the zeolite or the blast furnace slag; according to the soil improvement filler, basic characteristic indexes of the improver to be considered comprise organic matter content, specific surface area, cation exchange capacity, particle filling density and porosity, the absorption efficiency of the improver is determined through an isothermal absorption experiment, and the improver is screened according to the principle of high efficiency, easiness in obtaining and low cost. After the purification method disclosed by the invention is used, heavy metal ions such as cadmium, lead and arsenic and toxic and harmful substances in the soil are removed or degraded to a certain degree.
Example 1
The invention relates to a method for purifying heavy metal contaminated soil, which is implemented according to the following steps:
step 1, adding an acid solution into soil polluted by heavy metals, carrying out acidification treatment, and then naturally drying to obtain acidified soil;
the acid solution is hydrochloric acid solution;
the acidification treatment time is 5;
the mass ratio of the soil to the acid solution is 100: 1;
step 2, adding soil improvement filler, deionized water and dithiocarbamate into the acidified soil, and stirring for 1-2 hours to obtain a mixed solution;
the mass ratio of the soil improvement filler to the deionized water to the dithiocarbamate is 10: 80-200: 5;
the preparation method of the soil improvement filler comprises the following steps:
step 2.1, mixing sponge iron, titanium dioxide, potassium permanganate and water, and then carrying out condensation reflux reaction to obtain a reaction solution;
the reflux reaction temperature is 150 ℃, and the reflux reaction time is 2 hours;
the mass ratio of sponge iron to titanium dioxide to potassium permanganate to water is 15: 5: 1: 100, respectively;
step 2.2, mixing the reaction liquid obtained in the step 2.1 with wood chips and a modifier, adjusting the pH of the reaction liquid to 8.0 by using an iron hydroxide solution, then putting the reaction liquid into a reaction kettle with a polyethylene tetrafluoro lining for hydrothermal reaction, washing the reaction liquid to be neutral by using deionized water after the reaction is finished, and drying to obtain a soil improvement filler;
the mass ratio of the reaction liquid to the wood chips to the modifier is 80: 10: 2;
the modifier is fly ash;
the mass concentration of the ferric hydroxide solution is 10 percent;
the hydrothermal reaction temperature is 110 ℃, and the hydrothermal reaction time is 5 hours;
step 3, adding a sodium carbonate solution and a lime nitrate solution into the mixed solution for solidification treatment, and then completing soil purification;
the mass ratio of the mixed solution to the sodium carbonate solution to the lime nitrate solution is 150: 8: 10;
the curing treatment time is 4 h;
the mass concentration of the lime hydrate solution and the sodium carbonate solution is 5 percent.
Example 2
The invention relates to a method for purifying heavy metal contaminated soil, which is implemented according to the following steps:
step 1, adding an acid solution into soil polluted by heavy metals, carrying out acidification treatment, and then naturally drying to obtain acidified soil;
the acid solution is hydrochloric acid solution or nitric acid solution;
the acidification treatment time is 8 h;
the mass ratio of the soil to the acid solution is 100: 1.5;
step 2, adding soil improvement filler, deionized water and dithiocarbamate into the acidified soil, and stirring for 1h to obtain a mixed solution;
the mass ratio of the soil improvement filler to the deionized water to the dithiocarbamate is 10: 80-200: 5;
the preparation method of the soil improvement filler comprises the following steps:
step 2.1, mixing sponge iron, titanium dioxide, potassium permanganate and water, and then carrying out condensation reflux reaction to obtain a reaction solution;
the reflux reaction temperature is 170 ℃, and the reflux reaction time is 3 hours;
the mass ratio of sponge iron to titanium dioxide to potassium permanganate to water is 15: 5: 1.5: 130;
step 2.2, mixing the reaction liquid obtained in the step 2.1 with wood chips and a modifier, adjusting the pH of the reaction liquid to 9.0 by using an iron hydroxide solution, then putting the reaction liquid into a reaction kettle with a polyethylene tetrafluoro lining for hydrothermal reaction, washing the reaction liquid to be neutral by using deionized water after the reaction is finished, and drying to obtain a soil improvement filler;
the mass ratio of the reaction liquid to the wood chips to the modifier is 80: 10: 6;
the modifier is green zeolite;
the mass concentration of the ferric hydroxide solution is 15 percent;
the hydrothermal reaction temperature is 115 ℃, and the hydrothermal reaction time is 5 hours;
step 3, adding a sodium carbonate solution and a lime nitrate solution into the mixed solution for solidification treatment, and then completing soil purification;
the mass ratio of the mixed solution to the sodium carbonate solution to the lime nitrate solution is 150: 8: 15;
the curing treatment time is 6 h;
the mass concentration of the lime-nitrate solution is 5 percent, and the mass concentration of the sodium carbonate solution is 8 percent.
Example 3
The invention relates to a method for purifying heavy metal contaminated soil, which is implemented according to the following steps:
step 1, adding an acid solution into soil polluted by heavy metals, carrying out acidification treatment, and then naturally drying to obtain acidified soil;
the acid solution is hydrochloric acid solution or nitric acid solution;
the acidification treatment time is 8 h;
the mass ratio of the soil to the acid solution is 100: 1.5;
step 2, adding soil improvement filler, deionized water and dithiocarbamate into the acidified soil, and stirring for 2 hours to obtain a mixed solution;
the mass ratio of the soil improvement filler to the deionized water to the dithiocarbamate is 10: 100: 5;
the preparation method of the soil improvement filler comprises the following steps:
step 2.1, mixing sponge iron, titanium dioxide, potassium permanganate and water, and then carrying out condensation reflux reaction to obtain a reaction solution;
the reflux reaction temperature is 160 ℃, and the reflux reaction time is 3 hours;
the mass ratio of sponge iron to titanium dioxide to potassium permanganate to water is 15: 5: 1: 140 of a solvent;
step 2.2, mixing the reaction liquid obtained in the step 2.1 with wood chips and a modifier, adjusting the pH of the reaction liquid to 9.5 by using an iron hydroxide solution, then putting the reaction liquid into a reaction kettle with a polyethylene tetrafluoro lining for hydrothermal reaction, washing the reaction liquid to be neutral by using deionized water after the reaction is finished, and drying to obtain a soil improvement filler;
the mass ratio of the reaction liquid to the wood chips to the modifier is 80: 10: 6;
the modifier is one or two of fly ash, green zeolite, blast furnace slag and zeolite;
the mass concentration of the ferric hydroxide solution is 20 percent;
the hydrothermal reaction temperature is 140 ℃, and the hydrothermal reaction time is 8 hours;
step 3, adding a sodium carbonate solution and a lime nitrate solution into the mixed solution for solidification treatment, and then completing soil purification;
the mass ratio of the mixed solution to the sodium carbonate solution to the lime nitrate solution is 150: 8: 18;
the curing treatment time is 7 h;
the mass concentration of the lime-nitrate solution and the mass concentration of the sodium carbonate solution are both 8 percent.
Example 4
The invention relates to a method for purifying heavy metal contaminated soil, which is implemented according to the following steps:
step 1, adding an acid solution into soil polluted by heavy metals, carrying out acidification treatment, and then naturally drying to obtain acidified soil;
the acid solution is hydrochloric acid solution or nitric acid solution;
the acidification treatment time is 10 h;
the mass ratio of the soil to the acid solution is 100: 1.5;
step 2, adding soil improvement filler, deionized water and dithiocarbamate into the acidified soil, and stirring for 2 hours to obtain a mixed solution;
the mass ratio of the soil improvement filler to the deionized water to the dithiocarbamate is 10: 200: 5;
the preparation method of the soil improvement filler comprises the following steps:
step 2.1, mixing sponge iron, titanium dioxide, potassium permanganate and water, and then carrying out condensation reflux reaction to obtain a reaction solution;
the reflux reaction temperature is 180 ℃, and the reflux reaction time is 4 hours;
the mass ratio of sponge iron to titanium dioxide to potassium permanganate to water is 15: 5: 2: 200 of a carrier;
step 2.2, mixing the reaction liquid obtained in the step 2.1 with wood chips and a modifier, adjusting the pH of the reaction liquid to 9 by using an iron hydroxide solution, then putting the reaction liquid into a reaction kettle with a polyethylene tetrafluoro lining for hydrothermal reaction, washing the reaction liquid to be neutral by using deionized water after the reaction is finished, and drying to obtain a soil improvement filler;
the mass ratio of the reaction liquid to the wood chips to the modifier is 80: 10: 9;
the modifier is fly ash and blast furnace slag;
the mass concentration of the ferric hydroxide solution is 20 percent;
the hydrothermal reaction temperature is 140 ℃, and the hydrothermal reaction time is 8 hours;
step 3, adding a sodium carbonate solution and a lime nitrate solution into the mixed solution for solidification treatment, and then completing soil purification;
the mass ratio of the mixed solution to the sodium carbonate solution to the lime nitrate solution is 150: 8: 25;
the curing treatment time is 8 h;
the mass concentration of the lime-nitrate solution and the mass concentration of the sodium carbonate solution are both 5 percent.
Claims (3)
1. The method for purifying the soil polluted by the heavy metals is characterized by comprising the following steps:
step 1, adding an acid solution into soil polluted by heavy metals, carrying out acidification treatment, and then naturally drying to obtain acidified soil;
step 2, adding soil improvement filler, deionized water and dithiocarbamate into the acidified soil, and stirring for 1-2 hours to obtain a mixed solution;
the preparation method of the soil improvement filler comprises the following steps:
step 2.1, mixing sponge iron, titanium dioxide, potassium permanganate and water, and then carrying out condensation reflux reaction to obtain a reaction solution; the reflux reaction temperature is 150 ℃ and 180 ℃, and the reflux reaction time is 2-4 h;
step 2.2, mixing the reaction liquid obtained in the step 2.1 with wood chips and a modifier, adjusting the pH of the reaction liquid to 8.0-9.5 by using an iron hydroxide solution, and then putting the reaction liquid into a reaction kettle with a polyethylene tetrafluoro lining for hydrothermal reaction at the temperature of 110-; after the reaction is finished, washing the reaction solution to be neutral by using deionized water, and drying to obtain the soil improvement filler;
the modifier is one or two of fly ash, blast furnace slag and zeolite;
step 3, adding a sodium carbonate solution and a lime nitrate solution into the mixed solution for solidification treatment, and then completing soil purification;
the mass ratio of the mixed solution to the sodium carbonate solution to the lime nitrate solution is 150: 8: 10-25; the curing time is 4-8 h; the mass concentration of the lime-nitrate solution and the mass concentration of the sodium carbonate solution are both 5 to 8 percent.
2. The method for purifying soil polluted by heavy metal according to claim 1, wherein in the step 1, the acid solution is hydrochloric acid solution or nitric acid solution; the acidification treatment time is 5-10 h.
3. The method for purifying soil polluted by heavy metal according to claim 1, wherein in the step 2, the mass ratio of the soil improvement filler, the deionized water and the dithiocarbamate is 10: 80-200: 5.
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| US6238568B1 (en) * | 1999-05-06 | 2001-05-29 | General Atomics | Hydrothermal processing with phosphate additive |
| CN102357518A (en) * | 2011-07-20 | 2012-02-22 | 沈阳环境科学研究院 | Chemical stabilization compound medicament for reducing heavy metal leaching concentration of soil |
| CN104014583B (en) * | 2014-06-10 | 2016-01-20 | 苏州同和环保工程有限公司 | A kind of heavy-metal contaminated soil drip washing and heavy metal enrichment method and equipment thereof |
| CN107470343B (en) * | 2017-08-03 | 2020-07-17 | 上海市环境工程设计科学研究院有限公司 | Method for treating high-concentration lead-polluted soil by using composite reagent |
| CN110484270B (en) * | 2019-08-26 | 2021-10-29 | 广东佳德环保科技有限公司 | Soil remediation agent, soil remediation material and preparation method |
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