Eluting agent for repairing petroleum hydrocarbon contaminated soil and two-stage leaching method

Abstract

The invention relates to the technical field of soil remediation, and discloses an eluting agent for remediation of petroleum hydrocarbon contaminated soil and a two-stage eluting method. The eluting agent comprises an eluting agent A or an eluting agent B, the eluting agent A comprises the following components: sodium carbonate with the concentration of 1.0 to 3.0 g / L, sodium chloride with the concentration of 0.5 to 2.5 g / L, TritonX-100 with the concentration of 0.5 to 2.0 g / L and sodium dodecyl benzene sulfonate with the concentration of 1.5 to 5.5 g / L; according to the two-stage leaching method, two compounded leaching agents are used for treating high-concentration petroleum hydrocarbon contaminated soil through two stages. According to the technical scheme, the environment-friendly effect is achieved, and follow-up bioremediation is facilitated for further treatment of contaminated soil; according to the two-stage leaching method, the leaching agent A and the leaching agent B are adopted, the removal rate of petroleum hydrocarbon in the polluted soil is increased to 95% or above, secondary pollution to the environment is avoided, and the low-carbon and environment-friendly requirements are met.

Description

Technical Field

[0001] The invention relates to the technical field of soil remediation, and in particular to an eluent and a two-stage eluting method for remediating petroleum hydrocarbon-contaminated soil. Background Art

[0002] With the rapid development of the oil industry, oil will enter the soil environment during exploration, mining, transportation, storage and processing, causing soil salinization, asphaltization and compaction; it not only destroys the soil structure and function, leading to the deterioration of the living environment of microorganisms, but also causes radioactive pollution to the surrounding water and atmosphere, and even threatens human health in serious cases. Due to the characteristics of oil such as high fluidity, strong permeability and significant adhesion to soil, oil-contaminated soil has the characteristics of complex system, wide range, difficult treatment, long cycle and great harm.

[0003] Petroleum hydrocarbons that contaminate soil contain a large number of PAHs compounds (such as anthracene, phenanthrene and pyrene), polychlorinated biphenyl compounds (such as dioxins) and heavy metals. Due to the hydrophobicity and low water solubility of aromatic hydrocarbons, they can exist in the environment for a long time, so aromatic hydrocarbons are the most toxic to organisms, especially polycyclic aromatic hydrocarbons. And as the number of benzene rings increases, the lower the water solubility, the longer it exists in the environment, and the stronger the carcinogenicity. These substances have stable physical and chemical properties, strong toxicity and biological effects. The use of aqueous solution systems for green cleaning and remediation can effectively realize the resource utilization and harmless treatment of petroleum-contaminated soil. The key to this aqueous solution system lies in the application of eluents. At present, the elution effect of a single eluent on polycyclic aromatic hydrocarbons is poor, and the composition of the compound eluent is very likely to cause secondary pollution to the environment. Summary of the invention

[0004] The present application provides an eluent and a two-stage elution method for remediation of petroleum hydrocarbon-contaminated soil, so as to solve the above-mentioned technical problems of poor elution effect and secondary pollution caused by the prior art.

[0005] According to one aspect of the present application, an embodiment provides an eluent for remediation of petroleum hydrocarbon contaminated soil, including eluent A or eluent B;

[0006] The components of the eluent A include: sodium carbonate with a concentration of 1.0 to 3.0 g / L, sodium chloride with a concentration of 0.5 to 2.5 g / L, Triton X-100 with a concentration of 0.5 to 2.0 g / L, and sodium dodecylbenzene sulfonate with a concentration of 1.5 to 5.5 g / L;

[0007] The components of the eluent B include: sodium alginate with a concentration of 0.05-0.5 g / L, sodium citrate with a concentration of 0.006-0.02 g / L, and anhydrous sodium sulfate with a concentration of 0.02-0.08 g / L.

[0008] In one embodiment, the mass ratio of the sodium dodecylbenzene sulfonate to the TritonX-100 is 2:1 to 3.5:1.

[0009] According to one aspect of the present application, an embodiment provides a two-stage leaching method for remediation of petroleum hydrocarbon contaminated soil, comprising the following steps:

[0010] S1. Fully stirring the petroleum-contaminated soil and the eluent A as described above in a primary elution reactor to elute the pollutants from the soil;

[0011] S2. Pour the petroleum-contaminated soil and the elution solution in step S1 into a separator for separation, and add the separated petroleum-contaminated soil and the eluent B as described above into a secondary elution reactor and stir thoroughly;

[0012] S3. Separate the petroleum contaminated soil in the secondary elution reactor and rinse the separated petroleum contaminated soil with hot water.

[0013] In one embodiment, in step S1, the solid-liquid ratio of the petroleum contaminated soil and the eluent A is 1:20 to 1:60.

[0014] In one embodiment, in steps S1 and S2, sufficient stirring is performed at 25° C. and a rate of 160 r / min.

[0015] In one embodiment, in step S1, the stirring time is 3 hours; and / or,

[0016] In step S2, the stirring time is 7 hours.

[0017] In one embodiment, in step S2, the separator separates the petroleum contaminated soil by gravity separation.

[0018] In one embodiment, eluent A is used as the primary eluent, and eluent B is used as the secondary eluent.

[0019] In one embodiment, the volume ratio of eluent A to eluent B is 1:1 to 3:1.

[0020] In one embodiment, the two-stage leaching method for remediation of petroleum hydrocarbon contaminated soil further comprises the following steps:

[0021] S4. Recycle the flushing liquid obtained in step S3.

[0022] The technical solution of the above embodiment of the present application uses two compound eluents to treat petroleum hydrocarbon contaminated soil. The concentration of petroleum hydrocarbons in the soil obtained by multiple leaching is greatly reduced, and the removal rate reaches more than 80%. In addition, the two-stage leaching method for the remediation of petroleum hydrocarbon contaminated soil has a green and environmentally friendly effect, which is conducive to the subsequent bioremediation and further treatment of contaminated soil; it uses the eluent A and eluent B of the present invention to increase the removal rate of petroleum hydrocarbons in contaminated soil to more than 95%, and will not cause secondary pollution to the environment, meeting the requirements of low-carbon environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a graph showing the change in petroleum hydrocarbon removal rate in a single-stage and two-stage elution method within 10 hours in an embodiment;

[0024] Figure 2 The figure is a diagram showing the effect of different proportions of eluent on the removal of petroleum hydrocarbons in contaminated soil in an embodiment;

[0025] Figure 3 The figure is a diagram showing the effect of an eluent in an embodiment on the removal of petroleum hydrocarbons in soil contaminated with petroleum hydrocarbons of different concentrations. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0027] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.

[0028] It should be noted that the terms "first", "second" etc. in the present application are used to distinguish similar objects, and need not be used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged in appropriate circumstances, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, the process, method, system, product or equipment comprising a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0029] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element. Moreover, in this application, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element through a third element.

[0030] Embodiment 1

[0031] An embodiment provides an eluent for remediation of petroleum hydrocarbon contaminated soil, which includes eluent A; or, it includes eluent B. The components of the eluent A include: sodium carbonate with a concentration of 1.0 to 3.0 g / L, sodium chloride with a concentration of 0.5 to 2.5 g / L, TritonX-100 with a concentration of 0.5 to 2.0 g / L, and sodium dodecylbenzene sulfonate with a concentration of 1.5 to 5.5 g / L. The components of the eluent B include: sodium alginate with a concentration of 0.05 to 0.5 g / L, sodium citrate with a concentration of 0.006 to 0.02 g / L, and anhydrous sodium sulfate with a concentration of 0.02 to 0.08 g / L.

[0032] The use of the above-mentioned composite eluent to elute the petroleum-contaminated soil multiple times is conducive to the survival of the biological agent in the subsequent bioremediation. It is used in conjunction with the two-stage elution method (see Example 2 for details) to achieve a petroleum hydrocarbon removal rate of more than 95% in the final contaminated soil, solving the problems of poor elution effect and secondary pollution. Preferably, two elutions are performed. Among them, the effect is better when eluent A is used as the first eluent and eluent B is used as the second eluent.

[0033] In one embodiment, the mass ratio of the sodium dodecylbenzene sulfonate to the TritonX-100 is 2:1 to 3.5:1.

[0034] The method of using the above-mentioned eluent is particularly suitable for a two-stage elution method for remediation of soil contaminated by high-concentration petroleum hydrocarbons.

[0035] Embodiment 2

[0036] One embodiment provides a two-stage leaching method for remediation of petroleum hydrocarbon contaminated soil, comprising the following steps:

[0037] S1. Fully stirring the petroleum-contaminated soil and the eluent A described in Example 1 in a primary elution reactor to elute the pollutants from the soil; wherein the petroleum-contaminated soil and the eluent A are prepared in the primary elution reactor at a solid-liquid ratio of 1:20 to 1:60 (g / mL);

[0038] S2. Pour the petroleum-contaminated soil and the elution solution in step S1 into a separator for separation, and add the separated petroleum-contaminated soil and the eluent B described in Example 1 into a secondary elution reactor and stir thoroughly;

[0039] S3. Separate the petroleum contaminated soil in the secondary elution reactor and rinse the separated petroleum contaminated soil with hot water.

[0040] Furthermore, the flushing liquid obtained in step S3 can be further recycled.

[0041] In one embodiment, in steps S1 and S2, sufficient stirring is performed at 25°C and 160 r / min. Further, in step S1, the stirring time is 3 hours; in step S2, the stirring time is 7 hours.

[0042] In one embodiment, in step S2, the separator separates the petroleum contaminated soil by gravity separation.

[0043] In one embodiment, eluent A is used as the primary eluent, and eluent B is used as the secondary eluent. Preferably, the volume ratio of eluent A to eluent B is 1:1 to 3:1.

[0044] Embodiment 3

[0045] An embodiment provides a two-stage elution method using an eluent for remediation of soil contaminated by petroleum hydrocarbons.

[0046] Preparation of eluent:

[0047] Accurately weigh 1.0 g of sodium carbonate powder, 0.5 g of sodium chloride solid, and 1.0 g of Triton X-100, place in a beaker, add an appropriate amount of deionized water, heat and stir at a constant speed, then add 2.0 g of sodium dodecylbenzene sulfonate powder, stir to dissolve the mixture, and finally add deionized water to make up to 1 L to obtain the first eluent.

[0048] Accurately weigh 0.2 g of sodium alginate solid and 0.05 g of anhydrous sodium sulfate solid, place them in a beaker, add an appropriate amount of deionized water, stir at a uniform speed until the solid is dissolved, then add 20 mL of 0.5 g / L sodium citrate solution, and finally adjust the volume to 1 L to obtain a secondary eluent.

[0049] Washing method:

[0050] Accurately weigh 4g of contaminated soil with a petroleum hydrocarbon concentration of 5%, place it in a reactor, add 40mL of the first eluent at a solid-liquid ratio of 1:20 and a volume ratio of 1:1 for the second eluent, stir thoroughly for 3h at 25℃ and 160r / min to elute the pollutants from the soil, then discharge the contaminated soil and the eluted solution into a separator for gravity separation, add the separated soil to the secondary elution reactor, add 40mL of the secondary eluent, and stir for 7h at 25℃ and 160r / min; after completing the two washes, separate the mixture of contaminated soil and eluent in the reactor, rinse the separated soil with hot water, and take out the eluent and hot water rinse solution of the two leachings. By measuring the petroleum hydrocarbon content before and after soil elution, the removal rate is 82.1%.

[0051] Embodiment 4

[0052] An embodiment provides a two-stage elution method using an eluent for remediation of soil contaminated by petroleum hydrocarbons.

[0053] Preparation of eluent:

[0054] Accurately weigh 1.0 g of sodium carbonate powder, 0.5 g of sodium chloride solid, and 1.0 g of Triton X-100, place in a beaker, add an appropriate amount of deionized water, heat and stir at a constant speed, then add 2.0 g of sodium dodecylbenzene sulfonate powder, stir to dissolve the mixture, and finally add deionized water to make up to 1 L to obtain the first eluent.

[0055] Accurately weigh 0.2 g of sodium alginate solid and 0.05 g of anhydrous sodium sulfate solid, place them in a beaker, add an appropriate amount of deionized water, stir at a uniform speed until the solid is dissolved, then add 20 mL of 0.5 g / L sodium citrate solution, and finally adjust the volume to 1 L to obtain a secondary eluent.

[0056] Washing method:

[0057] Accurately weigh 4g of contaminated soil with a petroleum hydrocarbon concentration of 5%, place it in a reactor, add 60mL of the first eluent at a solid-liquid ratio of 1:30 and a volume ratio of 1:1 for the second eluent, stir thoroughly for 3h at 25℃ and 160r / min to elute the pollutants from the soil, then discharge the contaminated soil and the eluted solution into a separator for gravity separation, add the separated soil to the secondary elution reactor, add 60mL of the secondary eluent, and stir for 7h at 25℃ and 160r / min; after completing the two washes, separate the mixture of contaminated soil and eluent in the reactor, rinse the separated soil with hot water, and take out the eluent and hot water rinse solution of the two leachings. By measuring the petroleum hydrocarbon content before and after soil elution, a removal rate of 88.4% was obtained.

[0058] Embodiment 5

[0059] An embodiment provides a two-stage elution method using an eluent for remediation of soil contaminated by petroleum hydrocarbons.

[0060] Preparation of eluent:

[0061] Accurately weigh 1.0 g of sodium carbonate powder, 0.5 g of sodium chloride solid, and 1.0 g of Triton X-100, place in a beaker, add an appropriate amount of deionized water, heat and stir at a constant speed, then add 3.0 g of sodium dodecylbenzene sulfonate powder, stir to dissolve the mixture, and finally add deionized water to make up to 1 L to obtain the first eluent.

[0062] Accurately weigh 0.2 g of sodium alginate solid and 0.05 g of anhydrous sodium sulfate solid, place them in a beaker, add an appropriate amount of deionized water, stir at a uniform speed until the solid is dissolved, then add 20 mL of 0.5 g / L sodium citrate solution, and finally adjust the volume to 1 L to obtain a secondary eluent.

[0063] Washing method:

[0064] Accurately weigh 4g of contaminated soil with a petroleum hydrocarbon concentration of 5%, place it in a reactor, add 80mL of the first eluent at a solid-liquid ratio of 1:30 and a volume ratio of 2:1 for the second eluent, stir thoroughly for 3h at 25℃ and 160r / min to elute the pollutants from the soil, then discharge the contaminated soil and the eluted solution into a separator for gravity separation, add the separated soil to the secondary elution reactor, add 40mL of the secondary eluent, and stir for 7h at 25℃ and 160r / min; after completing the two washes, separate the mixture of contaminated soil and eluent in the reactor, rinse the separated soil with hot water, and take out the eluent and hot water rinse solution of the two leachings. By measuring the petroleum hydrocarbon content before and after soil elution, a removal rate of 88.0% was obtained.

[0065] Embodiment 6

[0066] An embodiment provides a two-stage elution method using an eluent for remediation of soil contaminated by petroleum hydrocarbons.

[0067] Preparation of eluent:

[0068] Accurately weigh 1.0 g of sodium carbonate powder, 0.5 g of sodium chloride solid, and 1.0 g of Triton X-100, place in a beaker, add an appropriate amount of deionized water, heat and stir at a constant speed, then add 3.0 g of sodium dodecylbenzene sulfonate powder, stir to dissolve the mixture, and finally add deionized water to make up to 1 L to obtain the first eluent.

[0069] Accurately weigh 0.2 g of sodium alginate solid and 0.05 g of anhydrous sodium sulfate solid, place them in a beaker, add an appropriate amount of deionized water, stir at a uniform speed until the solid is dissolved, then add 20 mL of 0.5 g / L sodium citrate solution, and finally adjust the volume to 1 L to obtain a secondary eluent.

[0070] Washing method:

[0071] Accurately weigh 4g of contaminated soil with a petroleum hydrocarbon concentration of 5%, place it in a reactor, add 80mL of the first eluent at a solid-liquid ratio of 1:20 and a volume ratio of 2:1 for the second eluent, stir thoroughly for 3h at 25℃ and 160r / min to elute the pollutants from the soil, then discharge the contaminated soil and the eluted solution into a separator for gravity separation, add the separated soil to the secondary elution reactor, add 40mL of the secondary eluent, and stir for 7h at 25℃ and 160r / min; after completing the two washes, separate the mixture of contaminated soil and eluent in the reactor, rinse the separated soil with hot water, and take out the eluent and hot water rinse solution of the two leachings. By measuring the petroleum hydrocarbon content before and after soil elution, a removal rate of 87.5% was obtained.

[0072] Embodiment 7

[0073] An embodiment provides a two-stage elution method using an eluent for remediation of soil contaminated by petroleum hydrocarbons.

[0074] Preparation of eluent:

[0075] Accurately weigh 1.5 g of sodium carbonate powder, 0.5 g of sodium chloride solid, and 1.0 g of Triton X-100, place in a beaker, add an appropriate amount of deionized water, heat and stir at a uniform speed, then add 3.0 g of sodium dodecylbenzene sulfonate powder, stir to dissolve the mixture, and finally add deionized water to make up to 1 L to obtain the first eluent.

[0076] Accurately weigh 0.2 g of sodium alginate solid and 0.05 g of anhydrous sodium sulfate solid, place them in a beaker, add an appropriate amount of deionized water, stir at a uniform speed until the solid is dissolved, then add 20 mL of 0.5 g / L sodium citrate solution, and finally adjust the volume to 1 L to obtain a secondary eluent.

[0077] Washing method:

[0078] Accurately weigh 4g of contaminated soil with a petroleum hydrocarbon concentration of 1.5%, place it in a reactor, add 80mL of the first eluent at a solid-liquid ratio of 1:30 and a volume ratio of 2:1 for the second eluent, stir thoroughly for 3h at 25℃ and 160r / min to elute the pollutants from the soil, then discharge the contaminated soil and the eluted solution into a separator for gravity separation, add the separated soil to the secondary elution reactor, add 40mL of the secondary eluent, and stir for 7h at 25℃ and 160r / min; after completing the two washes, separate the mixture of contaminated soil and eluent in the reactor, rinse the separated soil with hot water, and take out the eluent and hot water rinse solution of the two leachings. By measuring the petroleum hydrocarbon content before and after soil elution, a removal rate of 87.3% was obtained.

[0079] Embodiment 8

[0080] An embodiment provides a two-stage elution method using an eluent for remediation of soil contaminated by petroleum hydrocarbons.

[0081] Preparation of eluent:

[0082] Accurately weigh 1.5 g of sodium carbonate powder, 2.5 g of sodium chloride solid, and 1.0 g of Triton X-100, place in a beaker, add an appropriate amount of deionized water, heat and stir at a uniform speed, then add 3.0 g of sodium dodecylbenzene sulfonate powder, stir to dissolve the mixture, and finally add deionized water to make up to 1 L to obtain the first eluent.

[0083] Accurately weigh 0.2 g of sodium alginate solid and 0.05 g of anhydrous sodium sulfate solid, place them in a beaker, add an appropriate amount of deionized water, stir at a uniform speed until the solid is dissolved, then add 40 mL of 0.5 g / L sodium citrate solution, and finally adjust the volume to 1 L to obtain a secondary eluent.

[0084] Washing method:

[0085] Accurately weigh 4g of contaminated soil with a petroleum hydrocarbon concentration of 5%, place it in a reactor, add 80mL of the first eluent at a solid-liquid ratio of 1:30 and a volume ratio of 2:1 for the second eluent, stir thoroughly for 3h at 25℃ and 160r / min to elute the pollutants from the soil, then discharge the contaminated soil and the eluted solution into a separator for gravity separation, add the separated soil to the secondary elution reactor, add 40mL of the secondary eluent, and stir for 7h at 25℃ and 160r / min; after completing the two washes, separate the mixture of contaminated soil and eluent in the reactor, rinse the separated soil with hot water, and take out the eluent and hot water rinse solution of the two leachings. By measuring the petroleum hydrocarbon content before and after soil elution, a removal rate of 89.6% was obtained.

[0086] In the above-mentioned Embodiments 3 to 8, two compounded eluents are used to treat soil contaminated with high concentrations of petroleum hydrocarbons in two stages. Figure 1 It reflects the change of petroleum hydrocarbon removal rate in single-stage and two-stage elution methods within 10 hours. Figure 2 It reflects the removal effect of petroleum hydrocarbons in contaminated soil by eluents at different ratios. Figure 3 It reflects the removal effect of petroleum hydrocarbons by eluents on soils contaminated with different concentrations of petroleum hydrocarbons.

[0087] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A leaching agent for remediation of petroleum hydrocarbon contaminated soil, characterized in that: Including eluent A or eluent B; The components of the eluent A include: sodium carbonate with a concentration of 1.0 to 3.0 g / L, sodium chloride with a concentration of 0.5 to 2.5 g / L, Triton X-100 with a concentration of 0.5 to 2.0 g / L, and sodium dodecylbenzene sulfonate with a concentration of 1.5 to 5.5 g / L; The components of the eluent B include: sodium alginate with a concentration of 0.05-0.5 g / L, sodium citrate with a concentration of 0.006-0.02 g / L, and anhydrous sodium sulfate with a concentration of 0.02-0.08 g / L.

2. The eluent for remediation of petroleum hydrocarbon contaminated soil according to claim 1, characterized in that: The mass ratio of the sodium dodecylbenzene sulfonate to the TritonX-100 is 2:1 to 3.5:

1.

3. A two-stage leaching method for remediation of petroleum hydrocarbon contaminated soil, characterized in that: The following steps are involved: S1. Fully stirring the petroleum-contaminated soil and the eluent A according to claim 1 or 2 in a primary elution reactor to elute the pollutants from the soil; S2. Pour the petroleum-contaminated soil and the elution solution in step S1 into a separator for separation, and add the separated petroleum-contaminated soil and the eluent B described in claim 1 or 2 into a secondary elution reactor and stir thoroughly; S3. Separate the petroleum contaminated soil in the secondary elution reactor and rinse the separated petroleum contaminated soil with hot water.

4. A two-stage elution method for remediation of petroleum hydrocarbon contaminated soil according to claim 3, characterized in that: In step S1, the solid-liquid ratio of the petroleum contaminated soil and the eluent A is 1:20 to 1:

60.

5. A two-stage leaching method for remediation of petroleum hydrocarbon contaminated soil according to claim 3, characterized in that: In steps S1 and S2, sufficient stirring is performed at 25° C. and a speed of 160 r / min.

6. A two-stage leaching method for remediation of petroleum hydrocarbon contaminated soil according to claim 5, characterized in that: In step S1, the stirring time is 3 hours; and / or, In step S2, the stirring time is 7 hours.

7. A two-stage elution method for remediation of petroleum hydrocarbon contaminated soil according to claim 3, characterized in that: In step S2, the separator separates the petroleum-contaminated soil by gravity separation.

8. A two-stage elution method for remediation of petroleum hydrocarbon contaminated soil according to claim 3, characterized in that: Eluent A is used as the primary eluent, and eluent B is used as the secondary eluent.

9. A two-stage leaching method for remediation of petroleum hydrocarbon contaminated soil according to claim 3, characterized in that: The volume ratio of eluent A to eluent B is 1:1 to 3:

1.

10. A two-stage leaching method for remediation of petroleum hydrocarbon contaminated soil according to any one of claims 3 to 9, characterized in that: The following steps are also included: S4. Recycle the flushing liquid obtained in step S3.

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