CN104437539B - A kind of magnetic OMS-2 catalyst and the application of degradable organic pollutant thereof - Google Patents

Abstract

The invention discloses the preparation of a magnetic OMS-2 catalyst and its application in degrading organic pollutants. The magnetic OMS-2 catalyst is prepared by using nano-ferric iron tetroxide as a carrier and manganese oxide octahedral molecular sieve OMS-2 as an active component. The prepared magnetic catalyst acts on persulfate to generate strong oxidizing sulfuric acid free radicals as active substances, oxidatively decolorizes and degrades organic pollutants, and the catalyst can be recycled and reused after the reaction. The catalyst preparation method of the present invention is simple, and the obtained magnetic OMS-2 catalyst can continuously and efficiently catalyze and activate persulfate to degrade organic wastewater at room temperature for many times, and can be recycled and reused after the reaction, which can reduce industrial costs to the greatest extent. It has great application prospects in the field of refractory organic wastewater treatment.

Description

A kind of magnetic OMS-2 catalyst and its application in degrading organic pollutants

technical field

The invention belongs to the technical field of organic wastewater treatment, and in particular relates to a magnetic OMS-2 catalyst and its application for degrading organic pollutants.

Background technique

The protection of environmental water resources is currently a focus of global attention. With the rapid development of modern economy, high-concentration organic wastewater poses a threat to our precious water resources. Advanced oxidation technology is a printing and dyeing wastewater treatment technology that has attracted much attention in recent years, because it can generate strong oxidizing hydroxyl radicals (OH) during the reaction process, and OH reacts with various organic pollutants to oxidize until Degrade it into harmless or readily biodegradable intermediates. In recent years, the research on the degradation of refractory organic matter in wastewater based on sulfate radical (SO ₄ ^－ ·) advanced oxidation method has begun to develop. Persulfate has received great attention due to its strong oxidizing properties, high stability at room temperature, and good water solubility.

There are many ways to activate persulfate, including high-temperature pyrolysis, transition metal ions, light radiation, zero-valent iron, activated carbon, microwave and other methods. For example, the invention patent CN102531144A uses hydrogen peroxide and sodium persulfate to degrade organic pollutants. The synergistic effect in the process can effectively treat organic wastewater that is difficult to biochemically. Patent CN102583692B uses heterogeneous copper oxides to catalyze persulfate to generate sulfuric acid free radicals to treat organic pollutants in water, while patent CN102247891A uses divalent manganese ions and The complexing agent is loaded on the activated carbon, and the persulfate is catalyzed to produce highly active pentavalent manganese for water treatment. Invention patent "A method for degrading organic wastewater by activating persulfate with OMS-2" (CN201410242408.X), is to use OMS-2 with mixed valence manganese ions (Mn ²⁺ , Mn ³⁺ and Mn ⁴⁺ ) And the special structure of a large number of open interlayers and pores, as well as its cation exchange, molecular adsorption, redox, etc., are used to activate persulfate to degrade organic wastewater. Although OMS-2 can efficiently activate persulfate to degrade organic pollutants, it still has the disadvantage of being difficult to recycle.

Due to the characteristics of easy separation and recovery, magnetic materials have good application prospects in the field of wastewater treatment. Ferroferric oxide nanoparticles can be magnetized in an external magnetic field, and the magnetism disappears after the external magnetic field is removed. Most studies have immobilized the target material on magnetic ferroferric oxide nanoparticles to prepare magnetic materials. Zhang et al. (Chem. Commun., 2011, 47, 1890-1892) deposited nano-Fe ₃ O ₄ on the surface of OMS-2 nanowires by co-precipitation method, so that OMS-2 has both magnetic properties and maintains adsorption properties. Although this magnetic OMS-2 has adsorption properties, the preparation conditions of the catalyst are harsh, the process is complicated, and the magnetism is reduced because the ferroferric oxide on the surface is easily oxidized.

Contents of the invention

The object of the present invention is to provide a magnetic OMS-2 catalyst and its application in degrading organic wastewater pollutants. The invention aims to solve the technical problem that the catalyst is difficult to recover in the process of activating persulfate to degrade organic pollutants in the prior art.

The technical scheme that the present invention adopts for solving the above problems is as follows:

A magnetic OMS-2 catalyst, which is prepared by the following method:

Step 1, weighing potassium permanganate, manganese acetate and nanometer ferric oxide respectively, fully grinding after mixing;

Step 2, drying the above ground mixture at 60°C-120°C under sealed conditions for 0.5-6h;

Step 3: washing the treated mixture with water several times, drying at 60-120° C. for 1-6 hours, and grinding to prepare the magnetic OMS-2 catalyst.

Preferably, the molar ratio of potassium permanganate to manganese acetate in the step 1 is 0.3-1.4.

Preferably, the molar ratio of manganese to iron in step 1 is 0.5-2.4.

Preferably, the nanometer iron tetroxide in step 1 can be prepared by precipitation method, hydrothermal method, reflux method, sol-gel method or thermal decomposition method.

Preferably, the step 3 further includes: passing the ground mixture through a 200-mesh molecular sieve to prepare the magnetic OMS-2 catalyst.

The invention also discloses the application of the magnetic OMS-2 catalyst in degrading organic wastewater pollutants.

Preferably, the recovered magnetic OMS-2 catalyst can be used as a catalyst again to degrade organic wastewater pollutants.

The present invention also provides the method for said magnetic OMS-2 catalyst to degrade organic wastewater pollutants, specifically comprising the following steps:

(1) Add 20-1000 mg/L persulfate and 20-1000 mg/L of magnetic OMS-2 catalyst to the organic waste water, stir and place at room temperature, and degrade the organic waste water;

(2) After the organic wastewater is degraded, the magnetic OMS-2 catalyst in the wastewater is recovered by using a magnet.

Compared with the prior art, the beneficial effects of the present invention are as follows:

1. The preparation method of the magnetic OMS-2 catalyst of the present invention is simple, mild in operation, and easy for industrial production.

2. The magnetic OMS-2 catalyst prepared by the present invention has strong magnetism, is easy to recycle and reuse, and saves cost.

3. When the magnetic OMS-2 catalyst of the present invention is used to degrade pollutants, the amount of magnetic catalyst is low, the removal efficiency is high, the durability is good, the environment is friendly, and it meets the needs of actual water treatment.

detailed description

The technical solution of the present invention will be described in detail below in conjunction with the embodiments.

Example 1

Put 22.05g Mn(Ac) ₂ ·4H ₂ O (purity 99.0%), 9.48g KMnO ₄ (purity 99.0%), 5g nanometer Fe ₃ O ₄ in a mortar and grind with agate pestle for half an hour. Pour the ground mixture into a jar, seal it, and place it in a drying oven at 80°C for 4 hours. The dried mixture was washed with water four times, placed in a drying oven at 80° C. for 4 hours, ground again and passed through a 200-mesh standard sieve to obtain the magnetic OMS-2 catalyst.

Example 2

1) Add potassium monomonosulfate to 20mg/L acid orange II dye wastewater, and the concentration of potassium monomonosulfate in the wastewater is 400mg/L; 2) Add the magnetic OMS prepared in Example 1 to the wastewater solution- 2 catalysts, the concentration of the magnetic OMS-2 catalyst in waste water is 400mg/L; the decolorization rate of dyestuff after 10 minutes is 94%. In comparative experiment 1, only potassium peroxymonosulfate was added to the dye wastewater, and the decolorization rate was only 12% at the same pH value and the same time. In comparative experiment 2, only magnetic OMS-2 catalyst was added to the dye wastewater, and the decolorization rate was 43% at the same pH value and the same time.

Example 3

1) Add potassium monopersulfate to 20mg/L Acid Orange II dye wastewater, the concentration is 400mg/L; 2) add the magnetic OMS-2 catalyst prepared in Example 1 to the wastewater solution, the concentration is 400mg/L; 3) After 10 minutes of reaction, the magnetic OMS-2 catalyst was sucked out with a magnet; 4) The separated magnetic OMS-2 catalyst was reused, and new 20mg/L dye wastewater was added again, and potassium hydrogen persulfate of the same concentration was added , react for 10min. In this way, the magnetic OMS-2 catalyst was reused fifteen times, and the decolorization rate of dye wastewater after each reaction is shown in Table 1. It can be seen from the experimental data in Table 1 that the magnetic OMS-2 catalyst can be reused many times and still has high catalytic activity.

Table 1, the decolorization rate of magnetic OMS-2 reuse degradation wastewater

repeat times 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Decolorization rate (%) 94 97 96 93 96 89 90 85 82 82 77 74 70 65 66

Example 4

1) in the waste water that contains 20mg/L following dyestuff, add potassium peroxymonosulfate, concentration is 400mg/L; 2) add the magnetic OMS-2 catalyst that embodiment 1 prepares again in waste water solution, concentration is 400mg/L, After degradation at different times, the dye decolorization rate in wastewater is shown in Table 2. It can be seen from the data in Table 2 that the magnetic OMS-2 catalyst has a good degradation effect on various dyes.

Table 2, the dye decolorization rate of magnetic OMS-2 catalyst treatment for different time

Example 5

Put 11.025g Mn(Ac) ₂ ·4H ₂ O (purity 99.0%), 4.74g KMnO ₄ (purity 99.0%), 10g nanometer Fe ₃ O ₄ in a mortar and grind with agate pestle for half an hour. Pour the ground mixture into a jar, seal it, and place it in a drying oven at 80°C for 2 hours. The dried mixture was washed with water four times, then placed in a drying oven at 80° C. for 2 h, ground again and passed through a 200-mesh standard sieve to obtain a magnetic OMS-2 catalyst.

In 20mg/L acid orange Ⅱ dye waste water, add potassium hydrogen persulfate, the concentration of potassium hydrogen persulfate in waste water is 20mg/L; Add the magnetic OMS-2 catalyst that present embodiment prepares again in waste water solution, magnetic The concentration of OMS-2 in the wastewater was 1000mg/L; the decolorization rate of the dye was 76% after 10 minutes.

Example 6

Put 28.1g Mn(Ac) ₂ ·4H ₂ O (purity: 99.0%), 5.92g KMnO ₄ (purity: 99.0%), and 5g nano-Fe ₃ O ₄ in a mortar, and grind for half an hour with an agate pestle. Pour the ground mixture into a jar, seal it, and place it in a drying oven at 120°C for 0.5h. The treated mixture was washed with water four times, placed in a drying oven at 120° C. for 1 h, ground again and passed through a 200-mesh standard sieve to obtain a magnetic OMS-2 catalyst.

In 20mg/L acid orange Ⅱ dye waste water, add potassium hydrogen persulfate, the concentration of potassium hydrogen persulfate in waste water is 1000mg/L; Add the magnetic OMS-2 catalyst prepared by this embodiment again in waste water solution, magnetic The concentration of OMS-2 in the wastewater was 20 mg/L; the decolorization rate of the dye was 81% after 10 minutes.

Example 7

Put 22.05g Mn(Ac) ₂ ·4H ₂ O (purity 99.0%), 9.48g KMnO ₄ (purity 99.0%), 5g nanometer Fe ₃ O ₄ in a mortar and grind with agate pestle for half an hour. The ground mixture was poured into a jar, sealed and placed in a 60°C drying oven for 6 hours. The dried mixture was washed with water four times, placed in a drying oven at 60° C. for 6 h, ground again and passed through a 200-mesh standard sieve to obtain a magnetic OMS-2 catalyst.

In 20mg/L acid orange Ⅱ dye waste water, add potassium hydrogen persulfate, the concentration of potassium hydrogen persulfate in waste water is 400mg/L; Add the magnetic OMS-2 catalyst that present embodiment prepares again in waste water solution, magnetic The concentration of OMS-2 in the wastewater was 400mg/L; the decolorization rate of the dye was 87% after 10 minutes.

The above are only some preferred embodiments of the present invention, and the present invention is not limited to the content of the embodiments. For those skilled in the art, various changes and modifications can be made within the concept scope of the technical solution of the present invention, and any changes and modifications made are within the protection scope of the present invention.

Claims (8)

1. a magnetic OMS-2 catalyst is characterized in that, the catalyst is prepared by the following method: Step 1, weighing potassium permanganate, manganese acetate and nano ferric oxide respectively, grinding after mixing; Step 2, drying the aforementioned ground mixture at 60-120°C under sealed conditions for 0.5-6 hours; Step 3: washing the treated mixture with water several times, drying at 60-120° C. for 1-6 hours, and grinding to prepare the magnetic OMS-2 catalyst. 2. A magnetic OMS-2 catalyst as claimed in claim 1, characterized in that: the molar ratio of potassium permanganate to manganese acetate in the step 1 is 0.3-1.4. 3. A magnetic OMS-2 catalyst as claimed in claim 1, characterized in that: in the step 1, the molar ratio of manganese to iron is 0.5-2.4. 4. A kind of magnetic OMS-2 catalyst as claimed in claim 1, is characterized in that: the nano ferric oxide in described step 1 adopts precipitation method, hydrothermal method, reflux method, sol-gel method or heat Prepared by decomposition. 5. A magnetic OMS-2 catalyst as claimed in claim 1, characterized in that: said step 3 further comprises, passing the ground mixture through a 200-mesh molecular sieve to prepare the magnetic OMS-2 catalyst. 6. The application of the magnetic OMS-2 catalyst described in any one of claims 1-5 in the degradation of organic wastewater pollutants. 7. The application of the magnetic OMS-2 catalyst as claimed in claim 6 in the degradation of organic waste water pollutants is characterized in that: the reclaimed magnetic OMS-2 catalyst can be used as a catalyst again for the degradation of organic waste water pollutants . 8. the method for the magnetic OMS-2 catalyst degradation organic waste water pollutant described in any one of claim 1-5, the method comprises the steps: (1) Add 20-1000 mg/L persulfate and 20-1000 mg/L of magnetic OMS-2 catalyst to the organic waste water, stir and place at room temperature, and degrade the organic waste water; (2) After the organic wastewater is degraded, the magnetic OMS-2 catalyst in the wastewater is recovered by using a magnet.