Use of cobalt tin hydroxide for catalytic degradation of nicotine pollutants and method of preparation

Abstract

The application discloses a use and a preparation method of cobalt tin hydroxide CoSn(OH)6 for catalytic degradation of nicotine pollutants, wherein the cobalt tin hydroxide is a bimetallic hydroxide with a cubic structure and can catalyze and activate peroxymonosulfate to oxidatively degrade nicotine pesticides under normal temperature conditions, so as to remove the pollutants in water, and especially has a good degradation effect on acetamiprid (ACE).

Description

Technical Field

[0001] This invention belongs to the field of environmental protection materials technology, specifically relating to a cobalt-tin hydroxide catalytic degradation agent for nicotine pollutants and its preparation method. Background Technology

[0002] With economic and social development, water pollution has become increasingly serious. Even at very low concentrations, organic pollutants in water can cause serious harm to ecosystems and human health. How to degrade them from water has attracted great attention from monitoring agencies and the scientific community.

[0003] Advanced oxidation processes (AOPs) based on peroxymonosulfate can generate reactive oxygen species (ROS) from peroxymonosulfate and have been shown to effectively remove recalcitrant organic pollutants via radical and / or non-radical pathways. Therefore, catalytic activation of peroxymonosulfate is a key step in the removal of recalcitrant organic pollutants.

[0004] Currently, developing catalysts with high activation performance and low toxicity is of great significance in this field. Perovskite-based nanomaterials typically possess a cubic pm3m space group structure, offering broad applicability in tuning catalytic properties. In this structure, the original cation can be partially replaced by other cations with similar ionic radii without significantly distorting its original lattice. This flexibility allows for precise manipulation of the physicochemical and electronic properties of perovskites in various environmental applications. For example, MFeO3 (M = La, Bi, Cu), Cs2AgBiBr6, etc., have been shown experimentally to be catalysts capable of activating peroxymonosulfate for the degradation of organic pollutants. However, the use of CoSn(OH)6 with a nanocubic structure designed and synthesized by the inventors for activating peroxymonosulfate for the degradation of organic pollutants has not been reported before.

[0005] The inventors synthesized a bimetallic hydroxide catalyst, CoSn(OH)6, using a co-precipitation method. The results showed that the CoSn(OH)6 prepared in this invention exhibited superior degradation performance of acetamiprid in a peroxymonosulfate system compared to other metal catalysts, Fe2TeO6 and Fe... 1.8 Mn 0.2 TeO6, and within 12 minutes, CoSn(OH)6 catalyzed the activation of PMS (potassium persulfate) to degrade acetamiprid with a degradation efficiency of 100%. Advanced oxidation processes (AOPs) based on persulfate can generate reactive oxygen species (ROS) from persulfate. Studies have shown that the improvement in the catalytic efficiency of CoSn(OH)6 may be due to both free radical and non-free radical pathways, with the non-free radical pathway playing a dominant role. Summary of the Invention

[0006] This invention provides a use of cobalt-tin hydroxide CoSn(OH)6 for catalytic degradation of neonicotinic pesticide pollutants. This cobalt-tin hydroxide can activate PMS (potassium persulfate) to oxidize and degrade neonicotinic pesticide organic pollutants, such as acetamiprid (ACE), under room temperature conditions, and has a good degradation effect.

[0007] To achieve the objectives of this invention, the following implementation technical solutions are provided.

[0008] In one embodiment, the present invention provides a cobalt tin hydroxide CoSn(OH)6.

[0009] Preferably, in the above-described uses of the present invention, the catalytic degradation is the catalytic oxidation and degradation of nicotine-based pesticide pollutants using peroxymonosulfate.

[0010] Preferably, in the above-described use of the present invention, the peroxymonosulfate is potassium peroxymonosulfate (PMS).

[0011] Preferably, in the above-described uses of the present invention, the neonicotinoid pesticide is acetamiprid (ACE).

[0012] In the above-described uses of the present invention, the catalyst catalyzes the oxidation and degradation of neonicotinoid pesticide pollutants by peroxymonosulfate. Preferably, the peroxymonosulfate is potassium peroxymonosulfate, and the neonicotinoid pesticide pollutant is acetamiprid.

[0013] In another embodiment, a method for preparing a cobalt-tin bimetallic hydroxide catalyst CoSn(OH)6 is provided, comprising the following steps:

[0014] 1) Dissolve SnCl4·5H2O in anhydrous ethanol and ultrapure water, stir well to obtain solution 1;

[0015] 2) Dissolve CoCl2·6H2O and citric acid in ultrapure water and stir until homogeneous to obtain solution 2;

[0016] 3) Mix solution 1 and solution 2, stir for 10-20 minutes (preferably 15 minutes), add sodium hydroxide solution dropwise, stir the reaction thoroughly until the solution turns pink, then stop stirring;

[0017] 4) Centrifuge the pink solution, collect the pink precipitate, wash it 2-4 times continuously with a mixed solvent of ultrapure water and anhydrous ethanol, and dry it under vacuum to obtain the catalyst CoSn(OH)6.

[0018] In another embodiment described above, in the preparation method of the present invention, in step 1), the molar mass-volume ratio of SnCl4·5H2O to anhydrous ethanol and water in solution 1 is 1 mmol:5 mL:10 mL; in step 2), the molar mass-volume ratio of CoCl2·6H2O, citric acid and water in solution 2 is 1 mmol:1 mmol:40 mL; and in step 3), the molar ratio of sodium hydroxide to SnCl4·5H2O and CoCl2·6H2O is 10:1:1.

[0019] In another embodiment of the present invention, in step 3), the concentration of the sodium hydroxide solution is 2 mol / L; in step 4), the mixed solvent is ultrapure water and anhydrous ethanol in a volume ratio of 3:1, and the mixture is washed three times continuously and vacuum dried at 60°C.

[0020] In one specific embodiment, a method for preparing a cobalt-tin bimetallic hydroxide catalyst CoSn(OH)6 according to the present invention includes the following steps:

[0021] (1) Prepare materials: Weigh SnCl4·5H2O, CoCl2·6H2O, citric acid and NaOH according to the preset mass and set aside;

[0022] (2) Weigh out NaOH and prepare a 2 mol / L NaOH solution for later use;

[0023] (3) Dissolve SnCl4·5H2O in anhydrous ethanol and ultrapure water, stir evenly to obtain solution 1; dissolve CoCl2·6H2O and citric acid in ultrapure water, stir evenly to obtain solution 2; mix solution 1 and solution 2, stir thoroughly for 15 min to obtain mixed solution.

[0024] (4) Slowly add the NaOH solution from step (2) to the mixed solution from step (3), stir the reaction thoroughly until the solution turns pink, and then stop stirring.

[0025] (5) Centrifuge the pink solution, collect the pink precipitate, and wash it three times consecutively with a mixed solvent of ultrapure water and anhydrous ethanol.

[0026] (6) The pink precipitate obtained in the previous step was dried in a vacuum drying oven to obtain the catalyst CoSn(OH)6.

[0027] Furthermore, in step (3), the molar amount of SnCl4·5H2O is in the volume ratio of anhydrous ethanol and water as 1 mmol: 5 mL: 10 mL.

[0028] Furthermore, in step (3), the molar volume ratio of CoCl2·6H2O, citric acid and water is 1 mmol:1 mmol:40 mL.

[0029] Furthermore, in step (4), the reaction temperature is room temperature (21-24℃) and the reaction time is 1 hour.

[0030] Furthermore, in step (5), the mixed solvent is ultrapure water to anhydrous ethanol in a volume ratio of 3:1.

[0031] Furthermore, in step (6), the drying temperature is 60°C.

[0032] The acetamiprid (ACE) described in this invention is (E)-N1-[(6-chloro-3-pyridine)-methyl]-N2-cyano-N1-methylacetamide.

[0033] The catalyst of the present invention has the following beneficial effects:

[0034] 1) The novel catalyst of this invention is cobalt-tin hydroxide CoSn(OH)6, which has a cubic structure and belongs to perovskite-based nanomaterials, making it widely applicable in adjusting catalytic properties. Studies have found that this catalyst generates reactive oxygen species (ROS) and a large number of free radicals during the catalytic activation of peroxymonosulfate. Non-radical oxidation also occurs on the catalyst surface. Through a synergistic effect of free radical and non-radical pathways, it effectively degrades nicotinic acid-type pesticide pollutants, particularly exhibiting excellent degradation of ACE (acetic acid-like pollutants). The degradation effect is good, the catalytic properties are stable, and it is more conducive to environmentally friendly treatment. Furthermore, this catalyst can be recycled, saving resources.

[0035] 2) The novel catalyst of the present invention has simple and readily available raw materials, and the preparation method is simple, convenient and low cost, making it suitable for large-scale production. Attached Figure Description

[0036] Figure 1 XRD patterns of the catalyst CoSn(OH)6 prepared in Examples 1-6;

[0037] Figure 2 The XRD pattern of the catalyst CoSn(OH)6 prepared in Example 1 is compared with the standard XRD pattern of CoSn(OH)6.

[0038] Figure 3 The catalytic effect of the catalyst CoSn(OH)6 prepared in Example 1 on the activation of ACE, a peroxymonosulfate degradation product;

[0039] Figure 4 XRD comparison of the catalyst CoSn(OH)6 prepared in Example 1 before and after catalytic activation of peroxymonosulfate to oxidize and degrade nicotine-type pollutants ACE;

[0040] Figure 5The catalyst CoSn(OH)6 prepared in Example 1 was compared with other metal catalysts (Fe2TeO6, Fe catalyst synthesized at different temperatures). 1.8 Mn 0.2 Comparison of the effects of TeO6, CaSb2O6 (which also has a perovskite structure), SrSb2O6 and LiSnO3) on the catalytic activation of peroxymonosulfate oxidation and degradation of ACE;

[0041] Figure 6 The cyclic experimental results of the catalyst CoSn(OH)6 prepared in Example 1 for catalytic activation of peroxymonosulfate oxidation and degradation of nicotine-type pollutants ACE were shown. Detailed Implementation

[0042] The technical solutions of the present invention will be further described below with reference to the embodiments to help understand the essence of the present invention, but without limiting the scope of the present invention in any way.

[0043] Example 1: Preparation of Cobalt-Tin Bimetallic Hydroxide (CoSn(OH)6) Catalyst

[0044] The preparation process is as follows:

[0045] (1) Prepare materials: Weigh SnCl4·5H2O, CoCl2·6H2O, citric acid and NaOH according to the preset mass and set aside;

[0046] (2) Prepare the solution: Prepare a 2 mol / L NaOH solution from the NaOH weighed in step (1) for later use;

[0047] (3) Prepare solution: Dissolve 1 mmol SnCl4·5H2O in 5 mL of anhydrous ethanol and 10 mL of ultrapure water, stir well to prepare solution 1, and set aside.

[0048] Dissolve 1 mmol CoCl2·6H2O and 1 mmol citric acid in 40 mL of ultrapure water and stir until homogeneous to obtain solution 2. Mix solution 1 and solution 2 together and stir thoroughly for 15 min to obtain a mixed solution.

[0049] (4) Slowly add the 2 mol / L NaOH solution from step (2) to the mixed solution in step (3), stir the reaction thoroughly for 1 hour, and control the reaction temperature at room temperature (21-24℃) until the solution turns pink, then stop stirring.

[0050] (5) Centrifuge the pink solution from (4), collect the pink precipitate, and wash it three times consecutively with a mixed solvent of ultrapure water and anhydrous ethanol = 3:1.

[0051] (6) The washed pink precipitate was dried in a vacuum drying oven at 60°C to obtain the catalyst CoSn(OH)6.

[0052] Examples 2-6

[0053] The differences in the raw material ratios and reaction parameters between Examples 2-6 (corresponding to numbers 2-6) and Example 1 (corresponding to number 1) are shown in Table 1:

[0054] Table 1. Effect of different feedstock ratios on catalyst CoSn(OH)6

[0055]

[0056] Based on the raw material ratios and preparation parameters recorded in Table 1, the novel catalyst products CoSn(OH)6 of Examples 2-6 were prepared according to the preparation process in Example 1. All data in Examples 2-6 that are not recorded in Table 1 are the same as the data recorded in Example 1.

[0057] Characterization and determination of novel catalysts

[0058] The novel catalyst CoSn(OH)6 products prepared in Examples 1-6 are numbered 1-6. Samples 1-6 are thoroughly ground in an agate mortar, and then subjected to phase characterization tests using a Shimadzu 7000-X-ray diffractometer, yielding the following results: Figure 1 The XRD patterns shown have samples 1-6 arranged sequentially from top to bottom. Figure 1 middle.

[0059] To distinguish the novel catalyst from the standard XRD pattern of the double metal hydroxide CoSn(OH)6, the standard XRD patterns of Sample 1 (the catalyst prepared in Example 1) and CoSn(OH)6 were compared. Figure 2 As shown.

[0060] pass Figure 1 and Figure 2 The comparison shows that the present invention obtains a novel catalyst CoSn(OH)6 with a cobalt-tin bimetallic oxide structure through simple raw materials and a simple and convenient preparation process. The XRD pattern shows that the novel catalysts obtained in Examples 1-6 all have a bimetallic oxide structure.

[0061] Comparative experiment:

[0062] Three experimental solutions were prepared, and the pollutant to be degraded was 100 mL of acetamiprid solution (ACE) with a concentration of 10 mg / L.

[0063] Group 1: Add 50 mg CoSn(OH)6 catalyst and 30 mg peroxymonosulfate (PMS).

[0064] Group 2: Only 50 mg of CoSn(OH)6 catalyst was added.

[0065] Group 3: Only 30 mg of persulfate (PMS) was added.

[0066] The degradation reaction was carried out, with samples taken every 3 minutes until 12 minutes. The acetamiprid content was measured, and the degradation rate was calculated. The results are shown below. Figure 3 The results showed that CoSn(OH)6 and PMS alone could not degrade ACE, and only the synergistic effect of CoSn(OH)6 and PMS could achieve a good degradation effect.

[0067] After the first set of catalytic reactions was completed, the CoSn(OH)6 catalyst was collected and its XRD was analyzed. The results are shown in [Figure number missing]. Figure 4 The XRD pattern of CoSn(OH)6 before and after the catalytic reaction is basically the same, proving that the crystal form of the catalyst has not changed and can be recycled.

[0068] Catalytic application experiments

[0069] To further verify the catalytic performance of the novel catalyst CoSn(OH)6 of this invention, a control experiment was conducted. The catalyst CoSn(OH)6 prepared in Example 1 was compared with other metal catalysts such as Fe2TeO6 and Fe2TeO6 synthesized at different temperatures. 1.8 Mn 0.2 TeO6 was used to catalyze the oxidation and degradation of nicotine-type pollutants ACE by potassium persulfate (PMS), and the degradation rates of ACE were compared. Other metal catalysts used for catalytic effect comparison were synthesized according to conventional solid-phase methods in the art, and their preparation parameters are shown in Table 2.

[0070] Table 2. Preparation parameters of other metal catalysts

[0071]

[0072] The catalyst CoSn(OH)6 prepared in Example 1 was combined with the metal catalysts Fe2TeO6 and Fe prepared in Table 2. 1.8 Mn 0.2 TeO6, CaSb2O6, SrSb2O7, and LiSnO3 were used to conduct catalytic degradation experiments on acetamiprid solution (ACE).

[0073] Operating steps:

[0074] 1. Weigh 50 mg each of the catalyst CoSn(OH)6 prepared in Example 1 and the metal catalyst samples in Table 2;

[0075] 2. Add the weighed samples to 100 mL of acetamiprid solution (ACE) with a concentration of 10 mg / L, and allow to adsorb in the dark for 30 min to reach adsorption-desorption equilibrium;

[0076] 3. Add 35 mg of peroxymonosulfate (PMS) to the solution from the previous step. Take 2 mL of the supernatant every 3 minutes and add 2 mL of methanol at the same time. After filtration through a filter membrane, determine the degradation rate using high performance liquid chromatography (Agilent 1260).

[0077] The CoSn(OH)6 catalyst prepared in Example 1 and the metal catalysts in Table 2, such as Fe2TeO6 and Fe synthesized at different temperatures, are compared. 1.8 Mn 0.2 Table 3 shows the degradation rates of acetamiprid pollutants after adding 35 mg PMS for 12 min following dark adsorption of TeO6 and other perovskite-structured substances such as CaSb2O6, SrSb2O6, and LiSnO3 for 30 min:

[0078] Table 3. Degradation rate of ACE by the CoSn(OH)6 catalyst in Example 1 and the metal catalysts in Table 2

[0079] catalyst <![CDATA[CoSn(OH)6]]> <![CDATA[Fe2TeO6]]> <![CDATA[Fe 1.8 Mn 0.2 TeO6(750℃)]]> Degradation rate 100％ 7.96％ 22.72％ catalyst <![CDATA[Fe 1.8 Mn 0.2 TeO6(800℃)]]> <![CDATA[Fe 1.8 Mn 0.2 TeO6(850℃)]]> <![CDATA[Fe 1.8 Mn 0.2 TeO6(900℃)]]> Degradation rate 10.56％ 7.02％ 4.2％ catalyst <![CDATA[CaSb2O6]]> <![CDATA[SrSb2O6]]> <![CDATA[LiSnO3]]> Degradation rate 0.72％ 0.41％ 0.94％

[0080] The data in Table 3 show that the catalyst CoSn(OH)6 prepared in Example 1 exhibits the best degradation efficiency for acetamiprid (ACE), reaching 100%. Figure 5 The catalytic effect diagram shown is shown in the figure. ACE-Blank is the blank control group, which means that no catalyst was added to the acetamiprid solution. Figure 5 The results showed that the ACE solution with added catalyst CoSn(OH)6 achieved a 100% ACE degradation rate 12 min after the addition of PMS.

[0081] The comparison of the degradation effect data above shows that the novel catalyst CoSn(OH)6 of this invention has a very good degradation effect on nicotine-type pollutants ACE. This also indirectly proves that this invention can obtain a novel bimetallic oxide catalyst CoSn(OH)6 with a high degradation rate for nicotine-type pollutants using simple raw materials and a simple preparation method.

[0082] Cyclic experiment:

[0083] The catalyst CoSn(OH)6 that underwent the catalytic degradation reaction was washed three times with pure water and anhydrous ethanol in a 3:1 ratio, dried in a 60°C oven, and the recovered CoSn(OH)6 was replenished with 50 mg of the CoSn(OH)6 synthesized in Example 1. This was then added to 100 mL of 10 mg / L acetamiprid solution (ACE). After dark adsorption for 30 min, 35 mg of PMS was added. Every 3 min, 2 mL of the supernatant was collected, along with 2 mL of methanol. The mixture was filtered through a membrane and the degradation rate was determined by high-performance liquid chromatography (Agilent 1260). After the experiment, the CoSn(OH)6 was washed and dried, and the catalytic degradation experiment (i.e., the cyclic experiment) was repeated three times. The results are shown below. Figure 6 The results showed that CoSn(OH)6 catalyzes the activation of peroxymonosulfate (PMS) to oxidize and degrade acetamiprid (ACE). The catalytic properties are stable after repeated use and it can be recycled.

[0084] The novel cobalt-tin bimetallic hydroxide CoSn(OH)6 of this invention has a cubic structure and belongs to perovskite-based nanomaterials. It has wide applicability in adjusting catalytic properties, enabling the generation of reactive oxygen species (ROS) and a large number of free radicals during the catalytic activation of peroxymonosulfate. Non-free radical oxidation also occurs on the surface of the catalyst. Pollutants can be effectively degraded through both free radical and non-free radical pathways, especially showing excellent degradation of nicotinic acid-type pollutants ACE. The degradation effect is good and the catalytic properties are stable, making the novel catalyst of this invention more conducive to environmental protection. Moreover, the catalyst can be recycled, saving resources.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. The use of a cobalt-tin hydroxide (CoSn(OH)6) for the catalytic degradation of neonicotinoid pesticide pollutants, characterized in that: The catalytic degradation refers to the catalytic oxidation of peroxymonosulfate to degrade nicotine-based pesticide pollutants.

2. As described in claim 1, the peroxymonosulfate is potassium peroxymonosulfate.

3. As described in claim 1, the neonicotinoid pesticide is acetamiprid.

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