Axial Co-O coordination modified metalloporphyrin material as well as preparation and application thereof

Abstract

The invention relates to the technical field of halogenated organic matter treatment, in particular to an axial Co-O coordination modified metalloporphyrin material and preparation and application thereof. The invention provides a preparation method of an axial Co-O coordination modified metalloporphyrin material, which comprises the following steps: mixing cobalt porphyrin powder and reduced iron powder to obtain a mixture, then carrying out ball milling in an inert atmosphere, and forming axial Co-O coordination by cobalt atoms in the center of cobalt porphyrin and oxygen atoms on the surface of the reduced iron powder to obtain the axial Co-O coordination modified metalloporphyrin material. The axial Co-O coordination modified metalloporphyrin material is obtained. According to the method, cobalt porphyrin and reduced iron powder are mixed, cobalt atoms in the center of cobalt porphyrin are coordinated with oxygen atoms under the action of mechanical force, the axial Co-O coordination modified metalloporphyrin material is obtained, and the material can be used for solving the problem of treatment of high-concentration organic wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of halogenated organic compound treatment, and particularly to an axially Co-O coordinated modified metal porphyrin material and its preparation and application. Background Art

[0002] Halogenated organic 1,2-dichloroethane (1,2-DCA) is one of the most widely produced industrial chemicals globally and is widely used in the synthesis of pharmaceuticals, specialty surfactants, and functional polymers. Although 1,2-DCA is of great industrial significance, as a groundwater pollutant, especially its long-term presence in industrial sites, it poses a serious environmental risk. 1,2-DCA exposure is classified as a possible human carcinogen and is associated with neurological diseases, hepatotoxicity, and kidney damage. 1,2-DCA has a high persistence, and this persistence highlights the urgent need for effective pollution control strategies.

[0003] Common reductive dehalogenation methods include physical adsorption, electrochemical dechlorination, bioremediation, and chemical redox. However, the degradation effects of physical adsorption, bioremediation, and chemical redox on 1,2-DCA are very limited and almost cannot degrade it. Among them, the electrochemical dechlorination of 1,2-DCA has been proven to be a promising and economical dehalogenation strategy. However, due to its harsh dechlorination conditions, unclear reaction mechanism, and poor selectivity, this method is generally challenged in practice.

[0004] The catalytic conversion method is considered to be effective and green. The catalytic material can help with selective dehalogenation and convert the C-X bond into a relatively harmless C-H bond, which is a key environmental remediation method. However, the problems of the selection and development of catalytic materials have not been solved yet. Therefore, exploring more suitable catalytic materials to help achieve efficient and green treatment of 1,2-DCA is an urgent problem to be solved currently. Summary of the Invention

[0005] The present invention provides an axially Co-O coordinated modified metal porphyrin material and its preparation and application. Based on the principle of mechanochemistry, using mechanical shear force, impact force, and frictional force and other acting forces, cobalt porphyrin and reduced iron powder are mechanically ball-milled and modified, so that the central cobalt atom of cobalt porphyrin coordinates with the oxygen atom on the surface of the reduced iron powder to form a Co-O bond, and then a key iron oxide shell layer is obtained, which helps to improve the removal efficiency of halogenated organic compounds such as 1,2-DCA.

[0006] To achieve the above object, the present invention provides the following technical solutions: The present invention provides a method for preparing an axially Co-O coordinated modified metal porphyrin material, comprising: mixing cobalt porphyrin powder with zero-valent iron powder to obtain a mixture, and then ball-milling under an inert atmosphere, where the cobalt atom at the center of cobalt porphyrin forms an axial Co-O coordination with the oxygen atom on the surface of the zero-valent iron powder, and post-treating to obtain the axially Co-O coordinated modified metal porphyrin material.

[0007] In the present invention, after the cobalt porphyrin powder and the zero-valent iron powder are mixed, they interact with iron under the action of mechanochemistry, and cobalt coordinates with oxygen to obtain the axially Co-O coordinated modified metal porphyrin material. Experiments have proved that the axially Co-O coordinated metal porphyrin material obtained by the method proposed by the present invention effectively enhances the degradation ability of the zero-valent iron material to 1,2-DCA in water.

[0008] Preferably, the molar ratio of cobalt in the cobalt porphyrin powder to iron in the zero-valent iron powder is 0.006:1 to 0.008:1.

[0009] Preferably, the molar ratio of cobalt in the cobalt porphyrin powder to iron in the zero-valent iron powder is greater than or equal to 0.05:1.

[0010] When the dosage of Co gradually increases to a molar ratio of cobalt in the cobalt porphyrin powder to iron in the zero-valent iron powder of 0.05:1, the degradation of 1,2-DCA approaches 100%, and rapid degradation can be achieved within 1 h. When the dosage of cobalt porphyrin continues to increase, its degradation performance will not be significantly improved. Therefore, considering the cost, 0.05:1 is a better choice. However, a molar ratio greater than 0.05:1 is still within the scope protected by the present invention, and in practical applications, the addition ratio can be selected and adjusted according to actual needs.

[0011] Preferably, the particle size of the zero-valent iron powder is 2 to 30 μm.

[0012] Preferably, the zero-valent iron powder is elemental iron powder, reduced iron powder, cast iron powder, pig iron powder or industrial iron scraps containing zero-valent iron.

[0013] Preferably, the rotation speed of the ball-milling is 300 to 500 rpm.

[0014] Preferably, the ball-milling time is 2 to 30 h.

[0015] Preferably, the inert atmosphere includes nitrogen.

[0016] Preferably, the inert gas is nitrogen and / or argon.

[0017] Preferably, the post-treatment includes: cleaning the powder obtained by ball-milling.

[0018] Preferably, the reagent for cleaning is alcohol, acid or water.

[0019] Preferably, the alcohol is ethanol and / or methanol; more preferably, the water content in the alcohol is less than 0.1%.

[0020] Preferably, the acid is 1M acid; more preferably, the acid is at least one of sulfuric acid, hydrochloric acid or nitric acid.

[0021] Preferably, the water is deionized water or anaerobic water; more preferably, the water is anaerobic water.

[0022] The present invention also provides an axially Co-O coordinated modified metal porphyrin material prepared by the above method. The axially Co-O coordinated modified metal porphyrin material includes zero-valent iron and an iron oxide shell layer wrapped on the surface of the zero-valent iron. The iron oxide shell layer is formed by the coordination of the cobalt atom located at the center of cobalt porphyrin and the oxygen atom on the surface of the zero-valent iron powder via Co-O coordination.

[0023] Preferably, the thickness of the iron oxide shell layer is 5-15 nm; based on the mass of the axially Co-O coordinated modified metal porphyrin material, the mass of the zero-valent iron is 70-90 wt%.

[0024] Preferably, the particle size of the axially Co-O coordinated modified metal porphyrin material is 1-10 μm.

[0025] The present invention also provides the application of the axially Co-O coordinated modified metal porphyrin material prepared by the above method or the above axially Co-O coordinated modified metal porphyrin material in the repair and removal of halogenated organic compounds in high-concentration organic wastewater.

[0026] Preferably, the halogenated organic compound is at least one of 1,2-dichloroethane, tetrachloroethylene, chloroform, trichloroethylene and trans-1,2-dichloroethylene.

[0027] Preferably, the halogenated organic compound is 1,2-dichloroethane.

[0028] Preferably, the concentration of the halogenated organic compound is 10-400 ppm.

[0029] More preferably, the concentration of the halogenated organic compound is 10-200 ppm.

[0030] The present invention also provides a method for repairing and removing halogenated organic compounds in organic wastewater. The catalyst is put into the organic wastewater containing halogenated organic compounds, and the catalyst is the above axially Co-O coordinated modified metal porphyrin material.

[0031] Preferably, the dosage of the catalyst is 1-100 g / L; more preferably, the dosage of the catalyst is 5-50 g / L; more preferably, the dosage of the catalyst is 5-10 g / L.

[0032] Therefore, the present invention has the following beneficial effects: (1) In the present invention, cobalt porphyrin is mixed with reduced iron powder, and under the action of mechanical force, the cobalt atom in the center of cobalt porphyrin coordinates with oxygen atoms to obtain an axially Co-O coordinated modified metal porphyrin material.

[0033] (2) The axially Co-O coordinated modified metal porphyrin material synthesized by the method of the present invention has excellent removal effect on 1,2-DCA and can be used to solve the problem of treating high-concentration organic wastewater.

[0034] (3) The raw materials used in the method of the present invention are widely sourced, with low usage, the preparation process does not require high temperature, no wastewater and waste are generated, and it is safe to use.

[0035] (4) The technical method of the present invention is simple, highly practical, with mild reaction conditions, easy construction operation, high productivity, high repeatability, does not have excessive requirements for equipment, can carry out large-scale experiments, and has significant economic, environmental and social effects. Description of the Drawings

[0036] Figure 1 SEM-mapping diagram of the axially Co-O coordinated metal porphyrin material prepared in Example 1 of the present invention; Figure 2 SEM-mapping diagram of the ordinary iron powder material prepared in Comparative Example 1 of the present invention; Figure 3 Removal effect diagram of 1,2-DCA in Example 1 and Comparative Example 1; Figure 4 Effect comparison diagram of the degradation of 1,2-DCA by axially Co-O coordinated modified metal porphyrin materials with different Co / Fe molar ratios; Figure 5 Effect comparison diagram of the degradation of 1,2-DCA by axially Co-O coordinated modified metal porphyrin materials with different washing methods; Figure 6 Effect comparison diagram of the degradation of 1,2-DCA by axially Co-O coordinated modified metal porphyrin materials with different cobalt precursors; Figure 7 Removal effect diagram of different 1,2-DCA concentrations in Example 1. Detailed Embodiments

[0037] The present invention will be further described below in conjunction with specific embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are usually only a part of the embodiments of the present invention, rather than all of the embodiments. Therefore, all other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0038] In this part, the particle size of the reduced iron powder is 30 μm.

[0039]

Embodiment

[0040] Example 2 This example is basically the same as Example 1, except that: the molar ratio between cobalt and iron is 0.05, denoted as Co / Fe = 0.05.

[0041] Comparative Example 1 This comparative example is basically the same as Example 1, except that: take the reduced iron powder with the same total mass as that in Example 1 for ball milling, and keep other parameters unchanged to prepare a common iron powder material; denoted as pure-ZVI, where Co / Fe = 0.

[0042] Comparative Example 2 This comparative example is basically the same as Example 1, except that: it is washed with ethanol and denoted as Co-ZVI ethanol 。

[0043] Comparative Example 3 This comparative example is basically the same as Example 1, except that: it is washed with 1 mol / L sulfuric acid and denoted as Co-ZVI acid 。

[0044] Comparative Example 4 This comparative example is basically the same as Example 1, except that: cobalt porphyrin is replaced by cobalt cyclohexanediamine, and the molar ratio between cobalt and iron is still kept at 0.007.

[0045] Comparative Example 5 This comparative example is basically the same as Example 1, except that cobalt porphyrin is used to replace cobalt sulfophthalocyanine, and the molar ratio between cobalt and iron is still maintained at 0.007.

[0046] Comparative Example 6 This comparative example is basically the same as Example 1, except that the molar ratio between cobalt and iron is 0.003, denoted as Co / Fe = 0.003.

[0047] Comparative Example 7 This comparative example is basically the same as Example 1, except that the molar ratio between cobalt and iron is 0.005, denoted as Co / Fe = 0.005.

[0048] Comparative Example 8 This comparative example is basically the same as Example 1, except that the molar ratio between cobalt and iron is 0.01, denoted as Co / Fe = 0.01.

[0049]

Performance Test

[0050] 2. Degradation Efficiency The degradation experiment of 1,2-DCA is specifically as follows: Add the material into the bottle, and then add HEPEs buffer solution (50 mM, pH = 7) and 1,2-DCA to make the material concentration 10 g / L and the pollutant concentration 10 ppm. Samples are collected at specified time intervals, and then the concentration of 1,2-DCA in the headspace is analyzed using a gas chromatograph.

[0051] The degradation efficiencies of the materials prepared corresponding to Examples 1-2 and Comparative Examples 1-7 were measured respectively by the above degradation experiment method, and the results are as Figures 3-6 shown.

[0052] Figure 3For the Co-ZVI and pure-ZVI materials prepared corresponding to Example 1 and Comparative Example 1, observing Figure 3 the results shows that there is an obvious difference in the degradation effect of 1,2-DCA between the Co-ZVI material and the pure-ZVI material, indicating that the degradation efficiency of 1,2-DCA of the Co-ZVI material is greatly improved under the action of axial Co-O coordination.

[0053] Figure 4 Figure of the degradation efficiency of 1,2-DCA of the materials prepared at different cobalt-iron molar ratios. It can be observed that when the cobalt-iron molar ratio is 0.007, the degradation effect of the Co-ZVI material on 1,2-DCA reaches the best. When the cobalt-iron molar ratio increases to 0.05, the degradation can be completed within 1 h.

[0054] In addition, Figure 5 Figure of the degradation efficiency of 1,2-DCA of the materials prepared by different washing methods. It can be observed that when the material is washed with anaerobic water, the degradation effect of the CO-ZVI material on 1,2-DCA reaches the best.

[0055] Figure 6 Figure of the degradation efficiency of 1,2-DCA of the materials prepared from different cobalt precursors. Cobalt cyclohexanediamine and cobalt sulfonated phthalocyanine have a central cobalt coordination structure similar to that of cobalt porphyrin. However, the catalytic materials prepared from these three cobalt precursors with similar structures and properties show huge performance differences. This shows that only cobalt porphyrin has an axial Co-O coordination with the oxygen atoms on the surface of the reduced iron powder. It can be observed that when cobalt porphyrin is used as the cobalt source, the degradation effect of the Co-ZVI material on 1,2-DCA reaches the best.

[0056] 3. Influence of 1,2-DCA concentration on degradation efficiency The degradation experiment of 1,2-DCA with concentrations of 10 ppm, 40 ppm, 200 ppm, and 400 ppm was carried out using the Co-ZVI prepared in Example 1. The HEPEs buffer solution was changed to another prepared simulated surface water solution (pH = 7.65), and other degradation conditions were exactly the same as those provided in the "2. Degradation efficiency" section. The results were recorded in Figure 7 It was observed Figure 7 that as the concentration of 1,2-DCA increased, the corresponding degradation rate would decrease; generally speaking, high-concentration 1,2-DCA did not have a great inhibition on the degradation of Co-ZVI, that is to say, the Co-ZVI series materials provided by the present invention have wide applicability to the degradation of 1,2-DCA in high-concentration wastewater.

Claims

1. A method for preparing an axially Co-O coordinated modified metal porphyrin material, characterized in that, Comprising: Mix cobalt porphyrin powder with zero-valent iron powder to obtain a mixture, and then ball-mill it under an inert atmosphere. The cobalt atom at the center of cobalt porphyrin forms an axial Co-O coordination with the oxygen atom on the surface of the zero-valent iron powder, and then post-treat to obtain an axially Co-O coordinated modified metal porphyrin material.

2. The preparation method according to claim 1, characterized in that, The molar ratio of cobalt in the cobalt porphyrin powder to iron in the zero-valent iron powder is 0.006:1 to 0.008:1, or the molar ratio of cobalt in the cobalt porphyrin powder to iron in the zero-valent iron powder is greater than or equal to 0.05:

1.

3. The preparation method according to claim 1, wherein The particle size of the zero-valent iron powder is 2 - 30 μm.

4. The preparation method according to claim 1, characterized in that, The rotation speed of the ball milling is 300 - 500 rpm.

5. The preparation method according to claim 1, characterized in that, The post-treatment includes: washing the powder obtained by ball milling.

6. The axially Co-O coordinated modified metal porphyrin material prepared by the preparation method according to any one of claims 1 to 5, characterized in that, The axially Co-O coordinated modified metal porphyrin material includes zero-valent iron and an iron oxide shell layer wrapped on the surface of the zero-valent iron. The iron oxide shell layer is formed by the cobalt atom at the center of cobalt porphyrin and the oxygen atom on the surface of the reduced iron powder through axial Co-O coordination.

7. The axially Co-O coordinated modified metal porphyrin material according to claim 6, wherein The thickness of the iron oxide shell layer is 5 - 15 nm; calculated by the mass of the axially Co-O coordinated modified metal porphyrin material, the mass of the zero-valent iron is 70 - 90 wt%; the particle size of the axially Co-O coordinated modified metal porphyrin material is 1 - 10 μm.

8. Use of the axially Co-O coordinated modified metal porphyrin material prepared by the preparation method according to any one of claims 1 - 5 or the axially Co-O coordinated modified metal porphyrin material according to any one of claims 6 - 7 in the repair and removal of halogenated organic compounds in organic wastewater.

9. The application according to claim 8, characterized in that, The halogenated organic compound is at least one of 1,2-dichloroethane, tetrachloroethylene, chloroform, trichloroethylene, and trans-1,2-dichloroethylene.

10. A method for repairing and removing halogenated organic compounds in organic wastewater, characterized in that, Put the catalyst into the organic wastewater containing halogenated organic compounds. The catalyst is the axially Co-O coordinated modified metal porphyrin material prepared by the preparation method according to any one of claims 1 - 5 or the axially Co-O coordinated modified metal porphyrin material according to any one of claims 6 - 7.

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