阅读说明：本技术 一种表面活性剂-骨炭-层状氢氧化铁三元反应体系及其制备方法和应用 (Surfactant-bone charcoal-layered ferric hydroxide ternary reaction system and preparation method and application thereof ) 是由 殷炜昭 陈风敏 于 2021-08-17 设计创作，主要内容包括：本发明公开了一种表面活性剂-骨炭-层状氢氧化铁三元反应体系的制备方法,包括以下步骤：(1)在无氧的条件下,将阴离子表面活性剂溶液加入到固体骨炭中,充分混合,获得阴离子表面活性剂-骨炭悬浮液；(2)在无氧的条件下,将步骤(1)制备得到的阴离子表面活性剂-骨炭悬浮液与层状氢氧化铁悬浮液混合,制得表面活性剂-骨炭-层状氢氧化铁三元活性体系。本发明还公开了上述方法制备得到的表面活性剂-骨炭-层状氢氧化铁三元反应体系及其应用。本发明通过阴离子表面活性剂对骨炭预改性,增加骨炭表面的负电荷,加强带正电荷的层状氢氧化铁与带负电荷的骨炭接触和电子传递,对污染物的去除更加高效。(The invention discloses a preparation method of a surfactant-bone charcoal-layered ferric hydroxide ternary reaction system, which comprises the following steps: (1) adding an anionic surfactant solution into the solid bone charcoal under an anaerobic condition, and fully mixing to obtain an anionic surfactant-bone charcoal suspension; (2) and (2) mixing the anionic surfactant-bone char suspension prepared in the step (1) with the layered ferric hydroxide suspension under an anaerobic condition to prepare a surfactant-bone char-layered ferric hydroxide ternary active system. The invention also discloses a surfactant-bone charcoal-layered ferric hydroxide ternary reaction system prepared by the method and application thereof. According to the invention, the bone charcoal is pre-modified by the anionic surfactant, so that negative charges on the surface of the bone charcoal are increased, contact and electron transfer between the layered ferric hydroxide with positive charges and the bone charcoal with negative charges are enhanced, and pollutants are removed more efficiently.)

1. A preparation method of a surfactant-bone charcoal-layered ferric hydroxide ternary reaction system is characterized by comprising the following steps:

(1) adding an anionic surfactant solution into the solid bone charcoal under an anaerobic condition, and fully mixing to obtain an anionic surfactant-bone charcoal suspension;

(2) and (2) mixing the anionic surfactant-bone char suspension prepared in the step (1) with the layered ferric hydroxide suspension under an anaerobic condition to prepare a surfactant-bone char-layered ferric hydroxide ternary active system.

2. The method for preparing the surfactant-bone char-layered ferric hydroxide ternary reaction system according to claim 1, wherein the mass concentration of the anionic surfactant in the anionic surfactant solution in the step (1) is 0.02% to 0.32%.

3. The method for preparing the surfactant-bone char-layered ferric hydroxide ternary reaction system according to claim 1 or 2, wherein the anionic surfactant is one or more of sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium hexadecyl sulfonate, and sodium hexadecyl sulfate.

4. The method for preparing the surfactant-bone char-layered iron hydroxide ternary reaction system according to claim 1 or 2, wherein the mass ratio of the anionic surfactant to the bone char is greater than 2.0 and not more than 32.0.

5. The preparation method of the surfactant-bone char-layered iron hydroxide ternary reaction system according to claim 1, wherein the mass ratio of ferrous iron to bone char in the layered iron hydroxide suspension is greater than 0.01 and not more than 38.1.

6. The preparation method of the surfactant-bone char-layered ferric hydroxide ternary reaction system according to claim 1, wherein the layered ferric hydroxide suspension is prepared by the following steps:

(a) adding a glycine solution with the pH value of 7.8-8.0 into FeCl under the conditions of no oxygen, room temperature and stirring₂In the solution, adjusting the pH of the solution to 7.8-8.0 to obtain a glycine-ferrous iron mixed solution;

(b) FeCl is added under the conditions of no oxygen, room temperature and stirring₃And (b) injecting the solution into the glycine-ferrous iron mixed solution prepared in the step (a), and stabilizing the pH value of the system at 7.8-8.0 until the crystallization precipitate is completely separated out to obtain a layered ferric hydroxide suspension.

7. The method for preparing the surfactant-bone char-layered iron hydroxide ternary reaction system according to claim 6, wherein the glycine solution contains glycerolAmino acid and FeCl₂FeCl in solution₂The molar ratio of (2-9): 1.

8. the method for preparing the surfactant-bone char-layered iron hydroxide ternary reaction system according to claim 6, wherein glycine and FeCl are contained in the glycine solution₃FeCl in solution₃The molar ratio of (7-16): 1.

9. A surfactant-bone char-layered ferric hydroxide ternary reaction system is characterized by being prepared by the preparation method of the surfactant-bone char-layered ferric hydroxide ternary reaction system according to any one of claims 1 to 8.

10. The use of the ternary reaction system of surfactant-bone char-layered ferric hydroxide as claimed in claim 9, for remediation of soil or groundwater contaminated with organochlorine solvents.

Technical Field

The invention relates to the technical field of environmental remediation, and particularly relates to a surfactant-bone charcoal-layered ferric hydroxide ternary reaction system, and a preparation method and application thereof.

Background

Layered iron hydroxide, also known as patina, is a highly active Fe^II-Fe^IIILayered double hydroxide, capable of reacting to the environmentThe chlorinated solvent (such as trichloroethylene, carbon tetrachloride and the like), nitrate, nitroaromatic compounds and other oxidative pollutants have good removal capability. The high reducing activity of patina results from the large amount of structural ferrous iron in its crystal structure and its unique ferrous/ferric active sites. On the one hand, the abundant structural ferrous iron can provide a large number of electrons for the reduction reaction. On the other hand, the ferrous/ferric active sites can optimize the conductivity of the material and promote the electron transfer in the reduction reaction process. Researches show that the bone char can catalyze the patina to rapidly degrade the Chloroethylene (CEs), the patina alone cannot degrade the CEs, and the patina and bone char system can achieve rapid dechlorination of the CEs because graphitized components and quinone groups in the bone char can optimize the electron transfer process in the reaction process. The product of the reduction degradation of vinyl chloride by the green rust and bone char composite system is acetylene, no other chlorine-containing by-product is generated, and the method can be used for treating real polluted underground water. Before the effective patina-bone char suspension is injected into soil and underground water, a plurality of auxiliary technologies need to be researched to optimize the injection and mass transfer of materials in the highly heterogeneous environment of the soil and the underground water and accelerate the degradation efficiency of pollutants.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the invention aims to provide a preparation method of a surfactant-bone char-layered ferric hydroxide ternary reaction system, which is characterized in that the bone char is pre-modified by an anionic surfactant to increase the negative charge on the surface of the bone char, enhance the contact and electron transfer between the layered ferric hydroxide with positive charge and the bone char with negative charge, improve the fluid property of a suspension, improve the mass transfer efficiency of a medicament in soil and underground water media, and remove pollutants more efficiently by the prepared surfactant-bone char-layered ferric hydroxide ternary reaction system.

The invention also aims to provide a surfactant-bone charcoal-layered ferric hydroxide ternary reaction system prepared by the preparation method.

The invention further aims to provide application of the surfactant-bone charcoal-layered ferric hydroxide ternary reaction system.

The purpose of the invention is realized by the following technical scheme:

a preparation method of a surfactant-bone charcoal-layered ferric hydroxide ternary reaction system comprises the following steps:

(1) adding an anionic surfactant solution into the solid bone charcoal under an anaerobic condition, and fully mixing to obtain an anionic surfactant-bone charcoal suspension;

(2) and (2) mixing the anionic surfactant-bone char suspension prepared in the step (1) with the layered ferric hydroxide suspension under an anaerobic condition to prepare a surfactant-bone char-layered ferric hydroxide ternary active system.

Preferably, the mass concentration of the anionic surfactant in the anionic surfactant solution in the step (1) is 0.02 to 0.32 percent.

Preferably, the anionic surfactant is one or more of sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium hexadecyl sulfonate and sodium hexadecyl sulfate.

Preferably, the mass ratio of the anionic surfactant to the bone char is greater than 2.0 and not more than 32.0.

Preferably, the mass ratio of ferrous iron to bone char in the layered iron hydroxide suspension is greater than 0.01 and not more than 38.1, and more preferably, the mass ratio of ferrous iron to bone char in the layered iron hydroxide suspension is greater than 10 and not more than 20.

Preferably, the preparation process of the layered iron hydroxide suspension is as follows:

(a) adding a glycine solution with the pH value of 7.8-8.0 into FeCl under the conditions of no oxygen, room temperature and stirring₂In the solution, adjusting the pH of the solution to 7.8-8.0 to obtain a glycine-ferrous iron mixed solution;

(b) FeCl is added under the conditions of no oxygen, room temperature and stirring₃And (b) injecting the solution into the glycine-ferrous iron mixed solution prepared in the step (a), and stabilizing the pH value of the system at 7.8-8.0 until the crystallization precipitate is completely separated out to obtain a layered ferric hydroxide suspension.

Preferably, the glycine and FeCl in the glycine solution₂FeCl in solution₂The molar ratio of (2-9) to (1).

Preferably, the glycine and FeCl in the glycine solution₃FeCl in solution₃The molar ratio of (7-16): 1.

A surfactant-bone char-layered ferric hydroxide ternary reaction system is prepared by a preparation method of the surfactant-bone char-layered ferric hydroxide ternary reaction system.

An application of a surfactant-bone charcoal-layered ferric hydroxide ternary reaction system in remediation of soil or underground water polluted by an organic chlorine solvent.

The principle of the invention is as follows:

according to the invention, the negatively charged bone charcoal is premixed (modified) by the anionic surfactant, so that the anionic surfactant can be preferentially adsorbed on the active sites of the bone charcoal through the distribution effect. Meanwhile, a hydrophobic chain of the anionic surfactant can be tightly attached to the surface of bone charcoal to form an optimized structure, and organic pollutants are enriched at the active point position of the BC surface. In addition, the anionic surfactant can increase the negative charge on the surface of the bone char, and enhance the contact and electron transfer between the positively charged layered ferric hydroxide and the bone char, thereby optimizing the removal of pollutants.

The surfactant is an amphiphilic compound consisting of a hydrophilic group and a hydrophobic group, the organic pollutant is a hydrophobic pollutant, and the surfactant can dissolve more organic pollutants in an aqueous solution through the hydrophobic end, so that the reducing agent is facilitated to remove the organic pollutants. The invention forms a high-efficiency surfactant-bone charcoal-layered ferric hydroxide ternary reaction system by selecting a correct surfactant and a proper mixing mode, improves the mass transfer efficiency of the medicament and the reaction performance on organic pollutants, and has important significance for repairing polluted soil and underground water.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) according to the invention, through a surfactant-bone charcoal-layered ferric hydroxide ternary reaction system, negative charges on the surface of bone charcoal are increased, contact and electron transfer between the positively charged layered ferric hydroxide and the negatively charged bone charcoal are enhanced, and efficient removal of pollutants by the layered ferric hydroxide in soil and underground water environments is realized.

(2) According to the invention, through a surfactant-bone charcoal-layered ferric hydroxide ternary reaction system, the interaction among layered ferric hydroxide, bone charcoal and pollutants can be improved through the modification of the surfactant to the bone charcoal; the method is favorable for improving the fluid property of the suspension, solves the problems of difficult injection and uneven distribution of the medicament in inhomogeneous environment, and further optimizes the remediation effect on the polluted soil and underground water.

Drawings

Fig. 1 is a schematic diagram of a ternary reaction system of anionic surfactant-bone char-layered ferric hydroxide according to an embodiment of the present invention.

FIG. 2 is a graph showing the effect of dechlorination of Trichloroethylene (TCE) by using a ternary reaction system of anionic surfactant-bone charcoal-layered ferric hydroxide with different concentrations of Sodium Dodecyl Sulfate (SDS) in the example of the present invention.

FIG. 3 is a graph showing the effect of ternary reaction system of anionic surfactant-bone char-layered ferric hydroxide using SDS, sodium dodecyl Sulfate (SDF), and Sodium Dodecylbenzenesulfonate (SDBS) on TCE dechlorination in examples of the present invention.

FIG. 4 is a graph showing the effect of ternary reaction system of anionic surfactant-layered ferric hydroxide-bone char on TCE dechlorination using SDS of different concentrations in examples of the present invention.

FIG. 5 is a graph comparing the effect of ternary system of anionic surfactant-layered ferric hydroxide-bone char using SDS, SDBS, SDF on TCE dechlorination in the examples of the present invention.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.

The working mechanism of the surfactant-bone char-layered ferric hydroxide ternary active system prepared by the embodiment of the invention is as follows:

as shown in FIG. 1, the TCE degradation process in the surfactant-layered ferric hydroxide-bone char ternary reaction system can be divided into: firstly, an anionic surfactant 2 is preferentially adsorbed to the active site of bone charcoal 1 through a distribution function; hydrophobic chains of the anionic surfactant are tightly attached to the surface of the bone charcoal to form an optimized structure, so that organic pollutants are enriched at active sites on the surface of the bone charcoal; the negative charge of the surface of the bone charcoal is increased by the anionic surfactant, and the contact with the positively charged layered ferric hydroxide is strengthened; fourthly, the negative charges on the surface of the bone charcoal graphite structure mediate and catalyze the layered ferric hydroxide 4 with positive charges to transfer the electron e to the trichloroethylene 3; TCE is deoxidized and dechlorinated to acetylene 5.

Example 1

(1) Weighing 0.4g of sodium dodecyl sulfate, and dissolving the sodium dodecyl sulfate in 100mL of oxygen-free deionized water to obtain a sodium dodecyl sulfate solution with the mass concentration of 0.4% for later use;

(2) adding the sodium dodecyl sulfate solution obtained in the step (1) into 1g of bone charcoal under an anoxic condition, and fully mixing for more than 0.5h to obtain an anionic surfactant-bone charcoal suspension;

(3) and (3) under an anoxic condition, adding 2mL of the anionic surfactant-bone char suspension obtained in the step (2) into a 20mL headspace bottle containing 5mL of 60mM layered ferric hydroxide (the concentration of ferrous iron is 0.5mM) suspension, and mixing to obtain a surfactant-bone char-layered ferric hydroxide ternary active system.

The layered iron hydroxide suspension in the present example was prepared by the following method:

(a) 450mL of glycine solution (0.07mol/L) was adjusted to pH 8.0 with 1.0mol/L NaOH solution under oxygen-free, room temperature and stirring, and 20mL of FeCl was added₂Adjusting the pH of the solution (0.5mol/L) to 8.0 by using 1.0mol/L NaOH solution to obtain glycine-ferrous iron mixed solution;

(b) 20mL of FeCl were added under anaerobic, room temperature and stirring conditions₃(0.1mol/L) solution was injected into the glycine-bis (glycine-bis) prepared in step (1) at a rate of 5mL/min in four timesAnd (3) simultaneously dripping 1mol/L NaOH (the dripping speed is 3mL/min) into the iron valence mixed solution to stabilize the pH value of the system at 8.0, precipitating crystals of the layered iron oxide in the process, and obtaining a layered iron hydroxide suspension after the addition of the iron valence mixed solution is finished.

The method is applied to simulation test of remediation of soil or underground water polluted by organic chlorine solvent:

and (3) adding 50 mu L of trichloroethylene (4mM) into the surfactant-bone charcoal-layered ferric hydroxide ternary active system obtained in the step (3), reacting on a shaking table at 130-140rpm, sampling at regular time, and monitoring the degradation process of the trichloroethylene.

Example 2

The other conditions were the same as in example 1, wherein the mass concentration of sodium dodecylsulfate in step (2) was 0.02%.

Example 3

The other conditions were the same as in example 1, wherein the mass concentration of sodium dodecylsulfate in step (2) was 0.08%.

Example 4

The other conditions were the same as in example 1, wherein the mass concentration of sodium dodecylsulfate in step (2) was 0.16%.

Example 5

The other conditions were the same as in example 1, wherein the anionic surfactant in step (1) was changed to a sodium lauryl sulfate solution.

Example 6

The other conditions were the same as in example 1, wherein the anionic surfactant in step (1) was replaced with a sodium dodecylbenzenesulfonate solution.

Test results for examples 1-6:

in the surfactant-bone char-layered ferric hydroxide ternary active system of the embodiment of the invention, SDS with different concentrations (embodiments 1 to 4) is adopted, and the dechlorination effect on TCE is shown in fig. 2. Meanwhile, the dechlorination efficiency of the TCE is also increased along with the increase of the concentration of the SDS. Wherein, Control in the figure means that only deionized water is used, and green rust, bone char and surfactant are not used, namely blank.

As for the ternary active system of anionic surfactant-bone char-layered ferric hydroxide in the embodiment of the present invention, the dechlorination effect of TCE by using different anionic surfactants (examples 1, 5, and 6) is shown in FIG. 3, and it can be seen from the figure that the anionic surfactant modified bone char can accelerate the degradation of TCE by GR. Wherein, Control in the figure means that only deionized water is used, and green rust, bone char and surfactant are not used, namely blank.

Comparative example 1

(1) Weighing 0.4g of sodium dodecyl sulfate, and dissolving the sodium dodecyl sulfate in 100mL of oxygen-free deionized water to obtain a sodium dodecyl sulfate solution with the mass concentration of 0.4% for later use;

(2) under the anoxic condition, adding 1mL of the sodium dodecyl sulfate solution obtained in the step (1) into 5mL of 60mM layered ferric hydroxide (the concentration of ferrous iron is 0.5mM), and fully mixing for more than 0.5h to obtain an anionic surfactant-layered ferric hydroxide suspension;

(3) and (3) under an anoxic condition, adding 6mL of the anionic surfactant-layered ferric hydroxide suspension in the step (2) into a 20mL headspace bottle filled with 1mL of 10g/L bone charcoal suspension, and mixing to obtain a surfactant-layered ferric hydroxide-bone charcoal ternary active system.

Comparative example 2

The other conditions were the same as in comparative example 1, wherein the mass concentrations of sodium dodecylsulfate in step (2) were 0.02%, 0.08%, and 0.16%, respectively.

Comparative example 3

Other conditions were the same as in comparative example 1, wherein the anionic surfactant in step (1) was replaced with SDBS and SDF, respectively.

Test results for comparative examples 1-3:

aiming at the surfactant-layered ferric hydroxide-bone char ternary active system of the comparative example of the invention, SDS (comparative examples 1-2) with different concentrations is adopted, and the dechlorination effect on TCE is shown in figure 4, and as can be seen from the figure, different mixing modes are used, sodium dodecyl sulfate and layered ferric hydroxide are firstly combined, and finally bone char is added, so that the degradation efficiency of TCE is reduced compared with the sodium dodecyl sulfate-layered ferric hydroxide-bone char system.

The effect of dechlorination of TCE by using different anionic surfactants (comparative example 3) aiming at the ternary active system of anionic surfactant-layered ferric hydroxide-bone char of the comparative example of the invention is shown in figure 5, and the figure shows that the anionic surfactant modified GR slows down the degradation of TCE by GR. Therefore, the method is characterized in that firstly, the anionic surfactant and the bone charcoal are premixed, and then the layered ferric hydroxide is added, so that the key point for realizing the method is that the sequence of the steps has a crucial influence on the effect of the method.

In the above embodiment, the anionic surfactant may be one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium hexadecyl sulfonate, and sodium hexadecyl sulfate.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.