Iron-based phosphate radical intercalation double-metal hydroxide, preparation method thereof and method for inhibiting generation of chlorinated organic pollutants

Abstract

The invention provides an iron-based phosphate radical intercalation double-metal hydroxide, a preparation method thereof and a method for inhibiting generation of chlorinated organic pollutants, and belongs to the field of flue gas treatment. The invention provides an iron-based phosphate radical intercalated double-metal hydroxide for inhibiting generation of chlorinated organic pollutants. Metal ions of a metal layer main body of the iron-based phosphate radical intercalated double-metal hydroxide are iron ions and divalent metal ions; the intercalation anions comprise one or more of phosphate ions, monohydrogen phosphate ions and dihydrogen phosphate ions. Fe < 3 + > and divalent metal ions in the iron-based phosphate radical intercalated double-metal hydroxide have a synergistic effect, so that the material has excellent electronic regulation and catalytic performance, and the generation of chlorinated organic pollutants is inhibited; the phosphate ion intercalation can reduce the generation of chlorinated organic matters from the source; the layered structure of the iron-based phosphate radical intercalation double-metal hydroxide is beneficial to high-temperature dispersion and interface reaction, and generation of chlorinated organic pollutants is further inhibited.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flue gas treatment, in particular to an iron-based phosphate intercalation double-metal hydroxide and a preparation method thereof, and more particularly to a method for inhibiting the generation of chlorinated organic pollutants (such as chlorobenzene, chlorophenol, dioxin, etc.). BACKGROUND

[0002] With the wide application of municipal waste incineration, hazardous waste pyrolysis, and organic industrial high-temperature treatment technologies, the environmental emission of chlorinated organic pollutants (such as chlorobenzene, chlorophenol, dioxin, etc.) is becoming increasingly prominent. Such pollutants are highly toxic, difficult to degrade, and easily enriched, and conventional end-of-pipe treatment technologies (such as activated carbon adsorption and catalytic oxidation) have defects such as low treatment efficiency and poor thermal stability. Therefore, there is an urgent need for a material that is efficient and thermally stable to reduce the generation of these pollutants. SUMMARY

[0003] The present application provides an iron-based phosphate intercalation double-metal hydroxide and a preparation method thereof, and a method for inhibiting the generation of chlorinated organic pollutants. The iron-based phosphate intercalation double-metal hydroxide has a good inhibitory effect on the generation of chlorinated organic pollutants and is highly thermally stable.

[0004] The present application provides an iron-based phosphate intercalation double-metal hydroxide for inhibiting the generation of chlorinated organic pollutants. The metal ions in the metal layer of the iron-based phosphate intercalation double-metal hydroxide are iron ions and divalent metal ions. The intercalated anions include one or more of phosphate ions, monohydrogen phosphate ions, and dihydrogen phosphate ions.

[0005] Preferably, the divalent metal ions include one or more of Ca 2+ , Mg 2+ , and Mn 2+ .

[0006] Preferably, the molar ratio of the iron ions to the divalent metal ions is 1:10-30.

[0007] Preferably, the molar ratio of the iron ions to the phosphate ions is 1:10-20.

[0008] The present application also provides a preparation method of the iron-based phosphate intercalation double-metal hydroxide described in the above technical solution, which includes the following steps: Mixing a soluble iron salt, a soluble divalent metal salt, a phosphate salt, a strong base, and water, and then performing a hydrothermal reaction to obtain the iron-based phosphate intercalation double-metal hydroxide.

[0009] Preferably, the soluble iron salt includes ferric nitrate, and the anions in the soluble divalent metal salt include chloride ions and / or sulfate ions.

[0010] Preferably, the pH value of the mixed mixture is 9-10.

[0011] Preferably, the temperature of the hydrothermal reaction is 50-80℃, and the time is 12-36h.

[0012] The application also provides a method for inhibiting the generation of chlorinated organic pollutants, comprising the following steps: The iron-based phosphate intercalated double-metal hydroxide in the technical solution or prepared by the preparation method is added to the flue gas. The temperature of the flue gas is 100-500℃. Preferably, the mass ratio of the iron-based phosphate intercalated double-metal hydroxide to Cl in the flue gas is 200:1.

[0013] Fe in the iron-based phosphate intercalated double-metal hydroxide 3+ The synergistic effect with the divalent metal ions realizes the regulation of the electron density of the layer, so that the valence state distribution of the Fe center is more stable, thereby reducing the generation rate of active chlorides such as FeCl3 / Fe2O3; at the same time, the Fe 3+ The synergistic electronic redistribution with the divalent metal ions helps to capture free chlorine species, block the chlorinated free radical chain reaction, inhibit the generation of chlorinated organic pollutants, and finally generate low-activity metal chlorides or oxychlorides; the intercalation of phosphate ions can capture and passivate active chlorine and metal chlorides in the flue gas, inhibit the key step of catalytic chlorination reaction, and reduce the generation of chlorinated organic compounds from the source; in addition, the layered structure of the iron-based phosphate intercalated double-metal hydroxide is beneficial to high-temperature dispersion and interfacial reaction, and further inhibits the generation of chlorinated organic pollutants.

[0014] The iron-based phosphate intercalated double-metal hydroxide has a layered structure and a strong metal-oxygen bond (Fe–O–M), and can still maintain the integrity of the crystal layer under high-temperature conditions; at the same time, the intercalation of phosphate enhances the interlayer force and prevents structural collapse, so that the overall thermal stability is significantly better than that of ordinary LDH, and it is suitable for long-term use in high-temperature environments.

[0015] The application also innovates the application mode, which can be adapted to various industrial high-temperature thermal reaction scenes, directly added to the flue gas, simple operation, good stability, no secondary pollution introduced, diversified inhibition mechanism, can adapt to different flue gas composition and pollutant load, low dosage, low running cost, and is convenient for industrialization promotion. In addition, the method for inhibiting the generation of chlorinated organic pollutants is green and environmentally friendly, can be synthesized on a large scale, has significant application effect, and promotes the upgrading of high-temperature organic chlorine pollution control technology. DETAILED DESCRIPTION

[0016] The application provides an iron-based phosphate intercalated double-metal hydroxide for inhibiting generation of chlorinated organic pollutants, wherein metal ions in a metal layer body of the iron-based phosphate intercalated double-metal hydroxide are iron ions and divalent metal ions; and intercalated anions include one or more of phosphate ions, monohydrogen phosphate ions and dihydrogen phosphate ions.

[0017] In the application, the molar ratio of the iron ions to the divalent metal ions is preferably 1:10-30, and in specific embodiments of the application, the molar ratio can be 1:12, 1:15, 1:18, 1:20, 1:22, 1:25 or 1:28; and the divalent metal ions preferably include one or more of Ca 2+ , Mg 2+ and Mn 2+ .

[0018] In the application, the molar ratio of the iron ions to the phosphate ions is preferably 1:10-20, and in specific embodiments of the application, the molar ratio can be 1:13, 1:15 or 1:18.

[0019] The application further provides a preparation method of the iron-based phosphate intercalated double-metal hydroxide, comprising the following steps: mixing a soluble iron salt, a soluble divalent metal salt, a phosphate salt, a strong base and water, and then performing a hydrothermal reaction to obtain the iron-based phosphate intercalated double-metal hydroxide.

[0020] In the application, the soluble iron salt preferably includes ferric nitrate; and anions in the soluble divalent metal salt preferably include chloride ions and / or sulfate ions.

[0021] In the application, the phosphate salt preferably includes sodium dihydrogen phosphate.

[0022] In the application, the molar ratio of the iron ions in the soluble iron salt to the divalent metal ions in the soluble divalent metal salt and the molar ratio of the iron ions in the soluble iron salt to the dihydrogen phosphate ions in the phosphate salt are preferably the same as the molar ratio of the iron ions to the divalent metal ions and the molar ratio of the iron ions to the phosphate ions in the iron-based phosphate intercalated double-metal hydroxide.

[0023] In the application, the pH value of the obtained mixture after mixing is preferably 9-10, the strong base is preferably mixed in the form of a strong base solution, and the strong base preferably includes sodium hydroxide.

[0024] In the application, the temperature of the hydrothermal reaction is preferably 50-80℃, and the time is preferably 12-36h.

[0025] Preferably, after the hydrothermal reaction, the application further comprises: separating the product obtained by the hydrothermal reaction, and then washing and drying the obtained solid to obtain the iron-based phosphate intercalated double-metal hydroxide.

[0026] The application also provides a method for inhibiting the generation of chlorinated organic pollutants, comprising the following steps: The iron-based phosphate intercalated double-metal hydroxide in the technical solution or the iron-based phosphate intercalated double-metal hydroxide prepared by the preparation method is added into flue gas. The temperature of the flue gas is 100-500℃.

[0027] In the application, the mass ratio of the iron-based phosphate intercalated double-metal hydroxide to Cl in the flue gas is preferably 200:1.

[0028] The iron-based phosphate intercalated double-metal hydroxide, the preparation method thereof and the method for inhibiting the generation of chlorinated organic pollutants provided by the application are described in detail below in combination with examples, but they should not be understood as limiting the protection scope of the application.

[0029] Examples (1) Iron nitrate, calcium / magnesium chloride / manganese sulfate and sodium dihydrogen phosphate raw materials are weighed according to the molar ratio Fe:M:PO4=1:24:13, and are dissolved in deionized water; 3+ : M 2+ : PO4 3- =1:24:13; (2) Under stirring at 60℃, 1 mol / L NaOH solution is slowly added dropwise, and the pH of the mixed solution is adjusted to 9-10; (3) Continue to stir and age for 24h; (4) Centrifugal separation, deionized water washing until neutral, 60℃ drying for 12h, and obtaining the target LDH material.

[0030] Application examples Mg-FeLDH-PO4 material (mass ratio of Mg-FeLDH-PO4 material to Cl in flue gas is 200:1) is added to the flue gas area of a combustion simulation reactor at 400℃.

[0031] The contents of chlorobenzene, chlorophenol and dioxin in the flue gas of the blank control group (without adding material) and other control groups (traditional CaO retarder) are detected. The results are shown in Table 1.

[0032] Table 1: Test results of application examples and control groups

[0033] The results show that the inhibition rate of the material of the application on high-temperature chlorinated organic pollutants is much higher than that of the traditional retarder, and the material of the application has significant advantages.

[0034] The above description is only the preferred embodiment of the present application, it should be pointed out that for those skilled in the art, without departing from the principles of the present application, can make several improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. An iron-based phosphate intercalating bimetallic hydroxide for inhibiting the formation of chlorinated organic pollutants, characterized in that, The metal ions of the main body of the iron-based phosphate intercalated bimetallic hydroxide metal layer are iron ions and divalent metal ions; the intercalated anions include one or more of phosphate ions, monohydrogen phosphate ions and dihydrogen phosphate ions.

2. The iron-based phosphate intercalated bimetallic hydroxide according to claim 1, characterized in that, The divalent metal ions include Ca. 2+ Mg 2+ and Mn 2+ One or more of them.

3. The iron-based phosphate intercalated bimetallic hydroxide according to claim 1, characterized in that, The molar ratio of the iron ions to the divalent metal ions is 1:10~30.

4. The iron-based phosphate intercalated bimetallic hydroxide according to claim 1, characterized in that, The molar ratio of iron ions to phosphate ions is 1:10~20.

5. The method for preparing the iron-based phosphate intercalated bimetallic hydroxide according to any one of claims 1 to 4, characterized in that, Includes the following steps: A soluble iron salt, a soluble divalent metal salt, a phosphate, a strong base, and water are mixed and subjected to a hydrothermal reaction to obtain the iron-based phosphate intercalated bimetallic hydroxide.

6. The preparation method according to claim 5, characterized in that, The soluble iron salt includes ferric nitrate; the anions in the soluble divalent metal salt include chloride ions and / or sulfate ions.

7. The preparation method according to claim 5, characterized in that, The pH value of the mixture obtained by mixing is 9-10.

8. The preparation method according to claim 5, characterized in that, The hydrothermal reaction is carried out at a temperature of 50-80°C for a duration of 12-36 hours.

9. A method for inhibiting the formation of chlorinated organic pollutants, characterized in that, Includes the following steps: The iron-based phosphate intercalated bimetallic hydroxide according to any one of claims 1 to 4 or the iron-based phosphate intercalated bimetallic hydroxide prepared by the preparation method according to any one of claims 5 to 8 is added to the flue gas; The temperature of the flue gas is 100~500℃; The flue gas contains the element Cl.

10. The method according to claim 9, characterized in that, The mass ratio of the iron-based phosphate intercalated bimetallic hydroxide to the Cl element in the flue gas is 200:1.

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