CN115505405A - Chlorinated hydrocarbon solubilizing emulsion material based on waste grease and preparation method thereof - Google Patents

Abstract

The invention relates to a chlorinated hydrocarbon solubilizing emulsion material based on waste oil and a preparation method thereof. The emulsion material is composed of a light oil phase and a water phase, wherein the oil phase is kitchen waste edible oil, and the water phase is a compound surfactant solution including 0.45%~0.9% rhamnolipid and 0.05%~0.1% For Triton X-100, the volume ratio of oil phase to water phase is 0.25~0.5. The preparation method is to dissolve two surfactants in water to obtain a water phase solution, and gradually add an oil phase to mix the two during the stirring of the water phase. The invention prepares the emulsion material by compounding biosurfactant and waste oil, which can increase the dissolution efficiency of trichlorethylene in the water phase by 880 times, and the emulsion material has good pH stability, and can be used in neutral to alkaline environments. The invention is used to solubilize chlorinated organic pollutants, and the invention is expected to be applied to the field of in-situ remediation of pollutants in soil, groundwater and surface water.

Description

A kind of chlorinated hydrocarbon solubilizing emulsion material based on waste oil and its preparation method

technical field

The invention belongs to the technical field of environmental engineering, and specifically relates to a waste oil-biological surfactant emulsion capable of solubilizing chlorinated organic pollutants and a preparation method thereof, that is, a chlorinated hydrocarbon solubilizing emulsion material based on waste oil and its preparation method.

Background technique

Chlorinated hydrocarbons are an important chemical raw material widely used in industrial washing, degreasing of clothes, organic synthesis intermediates and other fields. They have carcinogenic, teratogenic and mutagenic toxicity, endanger human health and ecological safety, and are common groundwater pollutants. Including trichloroethylene (TCE), 1,1,1-trichloroethane, etc. Since chlorinated hydrocarbons have a higher density than water and are insoluble in water, once they enter the groundwater environment, they tend to migrate vertically downward into the low-permeability zone, forming a free-phase heavy non-aqueous phase liquid, which exists for a long time and causes pollution.

There are two methods of remediation of groundwater pollutants: ex-situ remediation (extraction) and in-situ remediation. In recent years, in-situ remediation has become the preferred choice and development trend for the remediation of typical organic contaminated sites such as chlorinated hydrocarbons due to its advantages of low disturbance and relatively low remediation cost. The development of the domestic soil and groundwater remediation industry is also gradually turning to long-term in-situ treatment. The remediation process needs to take into account both the degradation efficiency of pollutants and the environmental impact. The development of green and efficient solubilizing materials will help in-situ remediation technology in actual sites. Applications.

One of the important factors limiting the in situ degradation of chlorinated hydrocarbons is their availability. Chlorinated hydrocarbons mainly exist in four states: gas phase, free phase, residual phase and dissolved phase in groundwater. The chlorinated hydrocarbons in the dissolved phase are relatively small, but they directly affect human life and health, while the free phase chlorinated hydrocarbons are the main source of pollution in groundwater, which will continuously dissolve pollutants in groundwater and affect the quality and safety of groundwater. In in-situ remediation, the remediation material is generally injected into groundwater, and the natural hydraulic gradient is used to promote the contact between the remediation material and the pollution to improve degradation. Therefore, the pollutants and the remediation agent mainly react in the water phase, and the pollutants are not easy to enter the water phase. However, the remediation efficiency is reduced, especially in low-permeability sites, where both pollutants and remediation agents are difficult to diffuse. To improve the removal rate of pollutants, it is necessary to enhance the aqueous phase solubility and fluidity of chlorinated hydrocarbons.

Surfactant is a compound with both hydrophilic and lipophilic groups. When it reaches a certain concentration in aqueous solution, it can spontaneously form micelles (external hydrophilic and internal lipophilic) or reverse micelles (external hydrophilic and internal). Hydrophilic inside the oil), reduce the water-oil interfacial tension, and promote the dissolution of pollutants. When the oil phase liquid enters the interior of the surfactant micelles, it will be uniformly dispersed in water to form an opaque emulsion, which can promote the migration of chlorinated hydrocarbons in groundwater. Surfactants are combined with light oil to prepare emulsions to solubilize chlorinated hydrocarbons. Through mutual solubility between non-polar phases, on the one hand, it can provide greater capacity for chlorinated hydrocarbons to dissolve into water; on the other hand, it can reduce the amount of chlorinated hydrocarbons. density, bringing the chlorinated hydrocarbons in the aquifer floor into the water phase, thus facilitating the migration and degradation of chlorinated hydrocarbons in groundwater.

Solubilizing emulsion materials are currently mainly used in the fields of cosmetics, oil refining and flooding, and have only been gradually applied in the field of environmental restoration in recent years. Commonly used pollutant solubilizing materials are mainly chemical surfactants such as Tween 80 and sodium dodecyl sulfate (SDS), and compounds such as n-octane and n-hexane are used as light oil phases to prepare emulsions or microemulsions. Multiphase extraction or groundwater pumping treatment can significantly enhance the efficiency of pollutant remediation, but in situ remediation, the remediation agents injected into groundwater are difficult to recover. Therefore, it is more important to use easily degradable and environmentally friendly solubilized emulsion materials.

Contents of the invention

The object of the present invention is to provide a kind of chlorinated hydrocarbon solubilizing emulsion material based on waste oil and its preparation method for chlorinated hydrocarbon solubilization with waste oil as light oil phase and biosurfactant as water phase, In order to overcome the low solubilization efficiency of biosurfactants and the potential environmental risks of chemical surfactants, the solubilization of chlorinated organic pollutants by biosurfactants can be improved by adding a small amount of waste oil, so as to realize the goal of environmental pollution control. At the same time reduce secondary pollution and promote recycling of waste resources.

The purpose of the present invention is achieved through the following technical solutions:

A chlorinated hydrocarbon solubilizing emulsion material based on waste oil, consisting of an oil phase and a water phase; wherein, the oil phase is waste oil; the water phase includes an anionic surfactant and a nonionic surfactant agent, the mass ratio of the two in the water phase is 0.05% ~ 0.9%, 0.01% ~ 0.25% respectively; the volume ratio of the oil phase to the water phase is 0.25 ~ 4.

Further, the oil phase is kitchen waste cooking oil; the anionic surfactant is rhamnolipid, and the nonionic surfactant is Triton X-100, that is, the water phase The surfactant in the mixture is a compound solution of anionic surfactant rhamnolipid and nonionic surfactant Triton X-100 (polyethylene glycol octyl phenyl ether).

Further, the mass proportion of rhamnolipid in the water phase is 0.45% ~ 0.9%, the mass proportion of Triton X-100 in the water phase is 0.05% ~ 0.1%; the volume ratio of the oil phase to the water phase is 0.25 ~ 0.5.

Furthermore, the mass proportion of rhamnolipid in the water phase is 0.45%, the mass proportion of Triton X-100 in the water phase is 0.05%; the volume ratio of the oil phase to the water phase is 0.25.

The preparation method of the above-mentioned chlorinated hydrocarbon solubilizing emulsion material based on waste oil comprises the following steps:

A. According to the mass percentage of each component in the emulsion, weigh 0.05% ~ 0.9% rhamnolipid and 0.01% ~ 0.5% Triton X-100 respectively, dissolve them in deionized water, mix well, add alkali (NaOH ) adjusting the pH of the solution to 10-13 to obtain an aqueous phase;

B. Stir the above water phase solution continuously, slowly add waste oil according to the oil-water volume ratio of 0.25 ~ 4, and mix well to obtain the emulsion material.

Compared with prior art, the beneficial effect of the present invention is:

1. The method for preparing the emulsion of the present invention is simple, biodegradable, easy to operate, and easy to industrialized production.

2. The solubilizing emulsion in the present invention is composed of naturally degradable rhamnolipids and waste oils, which has less impact on the environment and is less prone to secondary pollution.

3. The rhamnolipid used in the preparation of the emulsion of the present invention can be produced by microbial fermentation, and the light oil phase is kitchen waste cooking oil. The materials for preparing the emulsion are all from waste resources, realizing the recycling of waste resources.

4. The solubilized emulsion prepared by the present invention has a good solubilizing effect on chlorinated hydrocarbons, and the solubilization efficiency of chlorinated hydrocarbons in the dissolved phase in water is increased by about 125 to 880 times, and the addition of waste oil can significantly increase the solubilization efficiency of chlorinated hydrocarbons. The solubility of organic pollutants in the water phase, and the mutual solubility of the light oil phase (waste grease, kitchen waste cooking oil) and chlorinated hydrocarbons can reduce the density of chlorinated hydrocarbons and promote their migration in the water phase.

5. The present invention provides a method for preparing a solubilized emulsion. Through a suitable ratio of rhamnolipid, Triton X-100 and waste oil, an opaque emulsion-like material is prepared for the solubilization and repair of groundwater chlorinated hydrocarbons.

6. The biosurfactant emulsion material and preparation method thereof for groundwater chlorinated hydrocarbon solubilization of the present invention is compounded by using biosurfactant rhamnolipid and chemical surfactant Triton X-100 and adding a small amount of Waste oil improves the solubilization of chlorinated organic pollutants by biosurfactants, overcomes the problems of low solubilization efficiency of biosurfactants and potential environmental risks of chemical surfactants, and realizes environmental pollution control while Reduce secondary pollution and promote recycling of waste resources.

7. The solubilized emulsion material prepared by the present invention has good pH stability, and can be used for solubilizing chlorinated organic pollutants in a neutral to alkaline environment. The solubilized emulsion material is expected to be applied to soil, groundwater, In situ remediation of pollutants in surface water.

Description of drawings

Fig. 1 is the particle size distribution figure of emulsion particle;

Fig. 2 is the zeta potential figure of emulsion;

Fig. 3 is the difference diagram of waste oil emulsion and n-octane emulsion to chlorinated hydrocarbon solubilizing ability;

Fig. 4 is a graph showing the solubilization ability of the emulsion to trichlorethylene at different pHs.

detailed description

The present invention will be further described below through specific embodiments and accompanying drawings. The following specific embodiments do not limit the technical solutions of the present invention in any form, and all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Example 1

A chlorinated hydrocarbon solubilizing emulsion material based on waste oil, consisting of an oil phase and a water phase, wherein the oil phase is kitchen waste cooking oil, and the water phase includes an anionic surfactant rhamnolipid (in the water phase The mass ratio is 0.05% ~ 0.9%) and the non-ionic surfactant Triton X-100 (the mass ratio in the water phase is 0.01% ~ 0.25%); the volume ratio of the oil phase to the water phase is 0.25 ~ 4.

The preparation method of the chlorinated hydrocarbon solubilizing emulsion material based on waste oil, comprises the following steps:

A. According to the different proportions of the components in the emulsion, weigh an appropriate amount of rhamnolipid (the mass ratio in the water phase is 0.05% ~ 0.9%), Triton X-100 (the mass ratio in the water phase is 0.01% ~ 0.25%) was dissolved in deionized water, mixed evenly, and alkali (NaOH) was added to adjust the pH of the solution to 10~13 to obtain an aqueous phase solution.

B. Stir the aqueous phase solution obtained above continuously, and slowly add the light oil phase according to a certain proportion (oil-water volume ratio 0.25 ~ 4) at the same time, continue stirring, and the solubilized solution will be obtained after the oil and water phases are mixed evenly. Emulsion material.

According to the different proportions in Table 1 (the concentration of rhamnolipid, the concentration of Triton X-100 and the volume ratio of oil phase to water phase are different), different emulsion materials are prepared for use.

Example 2

Solubilization Ability Test of Emulsion Materials to Chlorinated Hydrocarbons

Take trichlorethylene (TCE) as a representative of chlorinated organic pollutants, take 1 ml of TCE in a 40 mL borosilicate sample bottle, add 5 mL of the emulsion material in Example 1, shake at room temperature for 2 hours, and wash with n-hexane after shaking Trichlorethylene in emulsion was extracted, and Agilent gas chromatography (7890A) with ECD detector was used to determine the content of trichlorethylene in n-hexane.

Comparing the solubilization ratio of emulsion materials to TCE (compared to 260 mg/L of trichlorethylene dissolved in pure water), the results are shown in Table 1. Among them, when rhamnolipid is 0.45%, Triton X-100 is 0.05% And the emulsion with an oil-water ratio of 0.25 has a higher solubilization capacity (dissolution amount and solubilization ratio) for trichlorethylene, and when the content of Triton X-100 in the emulsion system reaches 0.25%, the solubilization ability of the emulsion for trichlorethylene decline.

Table 1 Solubilization ability of emulsion materials with different ratios to trichlorethylene

deal with Rhamnolipid concentration (%) Triton X-100 concentration (%) Oil Phase-Water Phase Ratio Trichlorethylene dissolved amount (g/L) Solubilization factor 1 0.09 0.01 0.25 155.9 600 2 0.09 0.01 1 158.0 607 3 0.09 0.01 4 166.9 642 4 0.05 0.05 0.5 220.1 846 5 0.05 0.05 1 197.2 758 6 0.05 0.05 2 197.8 761 7 0.45 0.05 0.25 229.4 882 8 0.45 0.05 0.5 204.1 785 9 0.45 0.05 2 222.1 854 10 0.25 0.25 0.5 32.5 125 11 0.25 0.25 4 23.1 88.8 12 0.9 0.1 0.5 206.7 795 13 0.9 0.1 2 197.3 759

Example 3

According to the results in Example 2, 0.45% rhamnolipid, 0.05% Triton X-100 and oil-water ratio of 0.25 were selected to measure the particle size and zeta potential of the emulsion.

The sample was placed in a cuvette, and the particle size and zeta potential of the emulsion were measured with a nanometer particle size and zeta potential meter (Malvern Zetasizer NanoZS90), and detected at room temperature. The test results of the particle size of the emulsion are shown in Figure 1, and the average particle size is 230 nm; the zeta potential of the emulsion is -58.2 mV (the result is shown in Figure 2), and it is generally believed that when the zeta potential of the system is less than -30 mV, it can form Stable suspension, so the prepared emulsion micelles have uniform particle size distribution and stable properties.

Example 4

The light oil phase was replaced by n-octane waste oil (kitchen waste cooking oil) to prepare emulsion materials, and the difference in the solubilization effect of chlorinated hydrocarbons was compared between the emulsions formed by two different light oil phases.

The water phase solution was prepared according to 0.45% rhamnolipid and 0.05% Triton X-100, and two different emulsion materials (n-octane Emulsion material and waste oil emulsion material), the preparation method is the same as embodiment 1.

Take 10 ul of TCE and 5 mL of n-octane/waste grease emulsion in a sample bottle, and measure the difference in the solubilization ability of the two emulsion materials to TCE, the specific method is the same as in Example 2. The results are shown in Figure 3. In comparison, the solubilization effect of the emulsion formed by waste oil on TCE is better than that formed by n-octane.

Example 5

Effects of Emulsions Under Different pH Conditions on Solubilization Ability of Chlorinated Hydrocarbons

Weigh an appropriate amount of rhamnolipid and Triton X-100 to dissolve in water, and adjust the solution to pH 10-14 with NaOH to obtain a final concentration of 0.45% rhamnolipid and 0.05% Triton X-100, with pHs of 10 and 11 respectively. , 12, 13, 14 five aqueous phase solutions. Emulsion materials at different pHs were prepared with an oil-water volume ratio of 0.25, and the specific preparation process of the emulsion was the same as in Example 1.

Gas chromatography was used to measure the solubilization of trichlorethylene by emulsion under different pH conditions. As shown in Figure 4, the solubilization ability of emulsion to trichlorethylene in the range of pH 10-13 maintained a good solubilization ability. When the pH reached 13.5, the solubilization ability of the emulsion to pollutants decreased significantly, indicating that the emulsion material composed of rhamnolipid, Triton X-100, and waste oil had good pH stability.

Claims (7)

1. A chlorinated hydrocarbon solubilizing emulsion material based on waste oil, characterized in that it is composed of an oil phase and a water phase; wherein, the oil phase is waste oil; the water phase includes an anionic surfactant and nonionic surfactants, the mass ratio of the two in the water phase is 0.05% ~ 0.9%, 0.01% ~ 0.25% respectively; the volume ratio of the oil phase to the water phase is 0.25 ~ 4. 2. the chlorinated hydrocarbon solubilizing emulsion material based on waste oil and fat according to claim 1, is characterized in that, described oily phase is kitchen waste cooking oil, and described anionic surfactant is rhamnolipid, and Described nonionic surfactant is Triton X-100. 3. the chlorinated hydrocarbon solubilizing emulsion material based on waste grease according to claim 2, is characterized in that, the mass ratio of rhamnolipid in water phase is 0.45%～0.9%, and Triton X-100 is in water phase The mass ratio of the medium is 0.05% ~ 0.1%; the volume ratio of the oil phase to the water phase is 0.25 ~ 0.5. 4. a kind of preparation method of the chlorinated hydrocarbon solubilizing emulsion material based on waste grease according to claim 2, is characterized in that, comprises the following steps: A. According to the mass percentage of each component in the emulsion, weigh 0.05% ~ 0.9% rhamnolipid and 0.01% ~ 0.25% Triton X-100 respectively, dissolve them in deionized water, mix well, add alkali to adjust the solution pH to 10~13 to obtain the aqueous phase; B. Stir the above water phase solution continuously, slowly add waste oil according to the oil-water volume ratio of 0.25 ~ 4, and mix well to obtain the emulsion material. 5. The preparation method of waste oil-based chlorinated hydrocarbon solubilized emulsion material according to claim 4, characterized in that, in the step A, NaOH is added to adjust the pH of the solution to 10-13. 6. the preparation method of the chlorinated hydrocarbon solubilizing emulsion material based on waste grease according to claim 4, is characterized in that, in described step A, take by weighing 0.45%～0.9% rhamnolipid, 0.05% rhamnolipid respectively ~ 0.1% Triton X-100, dissolved in deionized water. 7. The preparation method of chlorinated hydrocarbon solubilized emulsion material based on waste oil according to claim 4, characterized in that, in the step B, waste oil is slowly added at an oil-water volume ratio of 0.25 to 0.5.

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