阅读说明：本技术 一种镉铅砷污染土壤复合淋洗剂及其制备方法 (Cadmium-lead-arsenic contaminated soil composite eluting agent and preparation method thereof ) 是由 魏树和 徐雷 代惠萍 安婧 于 2021-09-22 设计创作，主要内容包括：本发明涉及一种镉铅砷污染土壤复合淋洗剂及其制备方法,所述一种镉铅砷污染土壤复合淋洗剂包括羟基乙叉二膦酸溶液、L-乳酸溶液、丙酮酸溶液和FeCl-(3)溶液；所述羟基乙叉二膦酸、L-乳酸、丙酮酸和FeCl-(3)溶液的体积比为：6:2:1:1。本发明的一种镉铅砷污染土壤复合淋洗剂的制备方法,所述制备方法为：(1)将10%的羟基乙叉二膦酸溶液、10%的L-乳酸溶液、10%的丙酮酸溶液和0.1 mol/L的FeCl-(3)溶液按照体积比为6:2:1:1进行混合,得到混合溶液A；(2)将混合溶液A置于往复式振荡器中震荡处理,即可,密封,避光保存。本发明通过将羟基乙叉二膦酸溶液、L-乳酸溶液、丙酮酸溶液、FeCl-(3)溶液进行复配,既能够实现对高镉铅砷污染土壤的高效淋洗,又可以避免对土壤的二次污染问题。(The invention relates to a cadmium-lead-arsenic polluted soil composite eluting agent and a preparation method thereof, wherein the cadmium-lead-arsenic polluted soil composite eluting agent comprises hydroxyethylidene diphosphonic acid solution, L-lactic acid solution, pyruvic acid solution and FeCl 3 A solution; the hydroxy ethylidene diphosphonic acid, L-lactic acid, pyruvic acid and FeCl 3 The volume ratio of the solution is: 6:2:1:1. The invention discloses a preparation method of a cadmium-lead-arsenic polluted soil composite eluting agent, which comprises the following steps: (1) 10 percent of hydroxyethylidene diphosphonic acid solution, 10 percent of L-lactic acid solution, 10 percent of pyruvic acid solution and 0.1mol/L FeCl 3 Mixing the solutions according to the volume ratio of 6:2:1:1 to obtain a mixed solution A; (2) and (4) placing the mixed solution A in a reciprocating oscillator for oscillation treatment, sealing, and storing in dark place. The invention is prepared by reacting hydroxyethylidene-bisPhosphonic acid solution, L-lactic acid solution, pyruvic acid solution, FeCl 3 The solution is compounded, so that not only can the high-efficiency leaching of the soil polluted by high cadmium, lead and arsenic be realized, but also the problem of secondary pollution to the soil can be avoided.)

1. A composite eluting agent for cadmium-lead-arsenic polluted soil, which is prepared from cadmium, lead and arsenicIs characterized in that the compound eluent comprises hydroxyethylidene diphosphonic acid solution, L-lactic acid solution, pyruvic acid solution and FeCl₃A solution;

the hydroxy ethylidene diphosphonic acid, L-lactic acid, pyruvic acid and FeCl₃The volume ratio of the solution is: 6:2:1:1.

2. The composite eluting agent for cadmium-lead-arsenic contaminated soil as claimed in claim 1, wherein the composite eluting agent further comprises a pH value regulator.

3. The composite eluting agent for cadmium-lead-arsenic contaminated soil as in claim 2, wherein the pH value adjusting agent is 0.1mol/L HCl or NaOH solution.

4. The composite eluting agent for soil polluted by cadmium, lead and arsenic as in claim 3, wherein the concentration of the hydroxyethylidene diphosphonic acid solution is 10%; the concentration of the L-lactic acid solution is 10 percent; the concentration of the pyruvic acid solution is 10%; the FeCl₃The concentration of the solution was 0.1 mol/L.

5. The preparation method of the cadmium-lead-arsenic polluted soil composite eluting agent as defined in any one of claims 2-4, wherein the preparation method comprises the following steps:

(1) mixing hydroxy ethylidene diphosphonic acid solution, L-lactic acid solution, pyruvic acid solution and FeCl₃Mixing the solutions to obtain a mixed solution A;

(2) placing the mixed solution A in a reciprocating type oscillator for oscillation treatment to obtain a solution B;

(3) and adding a pH value regulator into the solution B to regulate the pH =4 to obtain a composite eluting agent, sealing and storing in a dark place.

6. The preparation method of the cadmium-lead-arsenic contaminated soil composite eluting agent as defined in claim 5, wherein the oscillating treatment in the step (2) is: the oscillation frequency is 200 and 250 times/min, the time is 18-22min, and the temperature is 22-25 ℃.

Technical Field

The invention belongs to the technical field of heavy metal contaminated soil remediation, and particularly relates to a cadmium-lead-arsenic contaminated soil composite eluting agent and a preparation method thereof.

Background

Cadmium, lead and arsenic are common heavy metal pollutants, and cadmium, lead and arsenic and various heavy metals thereof can cause harm to human health after entering human bodies. Cadmium is easy to accumulate in the kidney after entering the human body, causes harm to the kidney and is easy to cause osteoporosis and soften; lead can cause serious damage to the blood system and nervous system of a human body and can seriously affect the growth and intelligence development of infants; arsenic entering the human body can cause serious harm to the skin, respiratory system, blood system and the like, and can seriously affect the physiological function of the human body, thereby causing abortion, sterility, deformity of infants and the like. In recent years, mining, metallurgy and other industrial processes drive economy to realize huge leap, and meanwhile, increasingly serious soil heavy metal pollution is caused, so that safety of agricultural and sideline products and human health are seriously endangered. At present, main remediation methods of cadmium-lead-arsenic heavy metal contaminated soil include a soil dressing and soil changing method, an electric remediation method, a solidification and stabilization method, a plant remediation method, a soil leaching method and the like, compared with the soil leaching method, other remediation methods have the problems of large influence on the soil environment, high cost, no fundamental removal of heavy metals and the like, and plant remediation is limited by low remediation effect, long remediation time and the like on various heavy metal contaminated soil. Therefore, the soil leaching is an ideal method for treating the cadmium-lead-arsenic polluted soil comprehensively. The eluting agent is the core of the eluting technology, but the existing eluting agent is often low in removing efficiency of the soil polluted by various heavy metals, so that the development of the eluting agent which is low in cost and efficiency, small in secondary pollution and capable of removing various heavy metals is necessary.

Disclosure of Invention

The invention aims to solve the problem of overcoming the defects in the prior art and provides a preparation method of a heavy metal composite eluting agent for cadmium-lead-arsenic polluted soil. The compound eluting agent has the characteristics of low price, high efficiency, simplicity, convenience, easy obtaining, small influence on soil environment and the like.

The composite eluting agent for the cadmium-lead-arsenic polluted soil comprises hydroxyethylidene diphosphonic acid solution, L-lactic acid solution, pyruvic acid solution and FeCl₃A solution;

said hydroxyethylidene diphosphonic acidL-lactic acid, pyruvic acid and FeCl₃The volume ratio of the solution is: 6:2:1:1.

Preferably, the compound eluting agent also comprises a pH value regulator.

Preferably, the pH value regulator is 0.1mol/L HCl or NaOH solution.

Preferably, the concentration of the hydroxyethylidene diphosphonic acid solution is 10%; the concentration of the L-lactic acid solution is 10 percent; the concentration of the pyruvic acid solution is 10%; the FeCl₃The concentration of the solution was 0.1 mol/L.

A preparation method of a cadmium-lead-arsenic polluted soil composite eluting agent comprises the following steps:

(1) mixing hydroxy ethylidene diphosphonic acid solution, L-lactic acid solution, pyruvic acid solution and FeCl₃Mixing the solutions to obtain a mixed solution A;

(2) placing the mixed solution A in a reciprocating type oscillator for oscillation treatment to obtain a solution B;

(3) and adding a pH value regulator into the solution B to regulate the pH =4 to obtain a composite eluting agent, sealing and storing in a dark place.

Preferably, the oscillating treatment in step (2) is: the oscillation frequency is 200 and 250 times/min, the time is 18-22min, and the temperature is 22-25 ℃.

The concentrations are volume concentrations.

The invention has the beneficial effects that:

(1) the invention adopts hydroxy ethylidene diphosphonic acid solution, L-lactic acid solution, pyruvic acid solution and FeCl₃The solution is compounded, so that not only can the high-efficiency leaching of the soil polluted by high cadmium, lead and arsenic be realized, but also the problem of secondary pollution to the soil can be avoided;

(2) the composite eluting agent for lead-arsenic contaminated soil can remove soil with high heavy metal content, and when Cd in the soil is 250-270 mg kg^-11100-As-260-280-mg kg-1, the removal rate of heavy metals cadmium can reach more than 81%, lead can reach more than 69%, arsenic can reach more than 55%, and the preparation method is simple; moreover, the pH value of the composite eluting agent is adjusted to ensure the removal rate of cadmium and lead and arsenic to reach over 72 percent and 60 percent respectivelyAnd simultaneously has little influence on the physical and chemical properties of the soil.

Detailed Description

In order to facilitate understanding of the present invention, the technical solutions of the present invention are further described below with reference to the specific embodiments, but the present invention is not limited thereto.

Example 1:

the composite eluting agent for the cadmium-lead-arsenic polluted soil comprises hydroxyethylidene diphosphonic acid solution, L-lactic acid solution, pyruvic acid solution and FeCl₃A solution;

the hydroxy ethylidene diphosphonic acid, L-lactic acid, pyruvic acid and FeCl₃The volume ratio of the solution is: 6:2:1: 1;

the concentration of the hydroxyethylidene diphosphonic acid solution is 10 percent; the concentration of the L-lactic acid solution is 10 percent; the concentration of the pyruvic acid solution is 10%; the FeCl₃The concentration of the solution was 0.1 mol/L.

A preparation method of a cadmium-lead-arsenic polluted soil composite eluting agent comprises the following steps:

(1) mixing 10% of hydroxyethylidene diphosphonic acid solution, 10% of L-lactic acid solution, 10% of pyruvic acid solution and 0.1mol/L of FeCl3 solution according to the volume ratio of 6:2:1:1 to obtain mixed solution A;

(2) placing the mixed solution A in a reciprocating type oscillator for oscillation treatment, wherein the oscillation frequency is 200 times/min, the oscillation time is 22min, the oscillation temperature is 25 ℃, and sealing and keeping away from light.

Example 2:

the composite eluting agent for the cadmium-lead-arsenic polluted soil comprises hydroxyethylidene diphosphonic acid solution, L-lactic acid solution, pyruvic acid solution and FeCl₃A solution;

the hydroxy ethylidene diphosphonic acid, L-lactic acid, pyruvic acid and FeCl₃The volume ratio of the solution is: 6:2:1: 1;

the composite eluting agent also comprises a pH value regulator;

the pH value regulator is 0.1mol/L HCl or NaOH solution;

the concentration of the hydroxyethylidene diphosphonic acid solution is 10 percent; the above-mentionedThe concentration of the L-lactic acid solution is 10 percent; the concentration of the pyruvic acid solution is 10%; the FeCl₃The concentration of the solution was 0.1 mol/L.

A preparation method of a cadmium-lead-arsenic polluted soil composite eluting agent comprises the following steps:

(1) 10 percent of hydroxyethylidene diphosphonic acid solution, 10 percent of L-lactic acid solution, 10 percent of pyruvic acid solution and 0.1mol/L FeCl₃Mixing the solutions according to the volume ratio of 6:2:1:1 to obtain a mixed solution A;

(2) placing the mixed solution A in a reciprocating type oscillator for oscillation treatment, wherein the oscillation frequency is 250 times/min, the oscillation time is 18min, and the oscillation temperature is 22 ℃, so as to obtain a solution B;

(3) and adding 0.1mol/L HCl or NaOH solution into the solution B to adjust the pH =4 of the solution B to obtain a composite eluting agent, sealing and storing in dark place.

Comparative example 1:

the hydroxy ethidene diphosphonic acid in the compound eluent of the embodiment 2 is replaced by the ethylenediamine tetraacetic acid, and the other steps are the same as the embodiment 2.

Comparative example 2:

the composite eluent did not include L-lactic acid, as in example 2.

Comparative example 3:

the composite eluent does not contain FeCl₃Otherwise, the same procedure as in example 2 was repeated.

Comparative example 4:

the composite eluent does not include hydroxyethylidene diphosphonic acid, as in example 2.

Comparative example 5:

the composite eluent does not comprise L-lactic acid and FeCl₃Otherwise, the same procedure as in example 2 was repeated.

The following is a specific application example of the heavy metal composite eluting agent applied to cadmium-lead-arsenic contaminated soil:

the soil contains 254.32 mg kg of cadmium^-1(ii) a 1169.97 mg kg of lead^-1(ii) a 270.64 mg kg of arsenic^-1Experiments were performed to determine the optimal washing conditions.

When the eluting agent is applied to the eluting treatment of cadmium-lead-arsenic polluted soil, the eluting agent specifically comprises the following steps: weighing about 1.00 g of soil sample into a 50 mL centrifuge tube, adding an equal amount of the composite eluent prepared by the invention into the corresponding centrifuge tube, and placing the centrifuge tube into a reciprocating type oscillator for oscillation (200 times/min, 25 ℃). And then centrifuging the vibrated centrifugal tube at the room temperature of 4000 r/min for 10 min, taking supernate and filtering the supernate through a 0.45-micron filter membrane, and measuring the concentration of cadmium, lead and arsenic in the solution by utilizing ICP-OES.

9 groups of the same and equal cadmium-lead-arsenic heavy metal polluted soil are taken, the same amount of the composite eluting agent in the embodiment 2 is added into each group of soil to carry out the leaching test of the heavy metal in the soil, and the test is designed according to the soil-liquid ratio and the leaching time; wherein, the soil-liquid ratio is the ratio of the soil mass (g) to the eluting agent volume (mL) in the test, and the eluting time is the oscillating and eluting time of the composite eluting agent and the soil in an oscillator; the test is carried out by adopting the leaching time of 12 h, 24 h and 48h with the soil-liquid ratio of 1:5, 1:10 and 1:20, and the results are shown in the table 1:

。

as can be seen from Table 1, the removal rates of cadmium, lead and arsenic in the soil of group 9 in the 9 tests were 81.62%, 72.32% and 61.75% respectively, which is the optimum removal rate of heavy metals. And further determining the optimal leaching condition soil-liquid ratio of 1:20, and leaching time of 48 h.

Under the best leaching condition, the removal effect of the composite leaching agents of the examples 1 and 2 of the invention on heavy metals in cadmium-lead-arsenic polluted soil is compared with that of the leaching agents of the comparative examples 1 to 5.

Application example 1:

the composite eluting agent of the embodiment 2 is applied to the place with the heavy metal content of cadmium of 250 mg kg^-11200 mg kg of lead^-1Arsenic 260mg kg^-1The polluted soil leaching treatment method specifically comprises the following steps: taking 0.1m × 0.1m × 0.05 m of surface soil of the field in a 20L plastic bucket, adding 14.4L of the compound eluting agent prepared in the embodiment 2 of the invention into the plastic bucket according to the optimal soil-liquid ratio of 1:20, and placing the mixture in a reciprocating oscillator to oscillate for 48h (200 times/min, 25 ℃). Then taking 20 mL of the mixed supernatant fluid to a centrifuge tube, centrifuging for 10 min at the room temperature of 4000 r/min, and takingThe supernatant was filtered through a 0.45 μm filter membrane, and the concentrations of cadmium, lead and arsenic in the solution were measured by ICP-OES, and the removal rates of heavy metals are shown in Table 2.

Application example 2:

the composite eluting agent of the embodiment 2 is applied to the sites with the heavy metal content of cadmium of 270 mg kg^-11150 mg kg of lead^-1Arsenic 270 mg kg^-1The contaminated soil was subjected to leaching treatment, and the removal rate of heavy metals was shown in table 2, which is otherwise the same as in application example 1.

Application example 3:

the composite eluting agent of the embodiment 2 is applied to the sites with the heavy metal content of cadmium of 260mg kg^-11100 mg kg of lead^-1280 mg kg of arsenic^-1The contaminated soil was subjected to leaching treatment, and the removal rate of heavy metals was shown in table 2, which is otherwise the same as in application example 1.

Application example 4:

the composite eluting agent of the embodiment 2 is applied to the site with the heavy metal content of cadmium of 254.32 mg kg^-1(ii) a 1169.97 mg kg of lead^-1(ii) a 270.84 mg kg of arsenic^-1The contaminated soil was subjected to leaching treatment, and the removal rate of heavy metals was shown in table 2, in the same manner as in application example 1:

。

the composite eluting agents of example 1 and comparative examples 1 to 5 were used for eluting heavy metal contaminated soil according to application example 4, and the results are shown in Table 3:

。

as can be seen from Table 3, the present application will employ hydroxyethylidene diphosphonic acid solution, L-lactic acid solution, pyruvic acid solution, FeCl₃The solution is compounded to interact, and the pH value of the compounded composite eluting agent is adjusted, so that the composite eluting agent can still keep higher removal rate on the soil polluted by high heavy metal.