A cobalt-nickel composite material based on nickel foam and its preparation method and application

Abstract

The present invention discloses a cobalt-nickel composite material based on nickel foam, and a preparation method and application thereof. The present invention pre-treats nickel foam NF to remove oxides and impurities of nickel foam, mixes cobalt salt, nickel salt and sodium thiosulfate in deionized water to obtain a precursor solution; adds the pre-treated nickel foam to the precursor solution, reacts at 138-142°C for 5-7h, cools to room temperature, washes and dries to obtain a cobalt-nickel composite material Co3S4 / Ni3S2@NF based on nickel foam. The composite material of the present invention can achieve 90.2% efficient removal of LOM within 60 minutes by activating PMS to generate highly active free radicals, and still has a good removal effect on LOM after 4 cycles of reaction, which well solves the problems of recycling and ion dissolution of powder catalysts. The material preparation method is simple and easy, suitable for large-scale production, and has broad application prospects and value.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a cobalt-nickel composite material Co3S4 / Ni3S2@NF based on nickel foam, and a preparation method and application thereof. Background Art

[0002] Emerging pollutants do not refer to new chemicals, but a class of pollutants that have existed in the environment for a long time, but their existence and importance have not been discovered until now. The discussion on the environmental hazards of emerging pollutants (EPs) was first proposed by Rachel Carson in 1962. In recent years, as more and more emerging pollutants enter the environment and cause known or unknown ecotoxicity and harm to human health, EPs have received more and more attention. Among them, pharmaceutical pollutants (PPs), as the most common EPs, are widely used in the treatment of diseases, but only a small amount of PPs are absorbed by living organisms, and the rest of the PPs are eventually excreted from the body in the form of residues and metabolites in the form of feces and urine. The current treatment technology for excreted PPs is through sewage treatment plants, but due to its stable structure and difficulty in decomposition, some PPs will eventually appear in the environment. At present, the presence of antibiotics has been detected in water bodies at home and abroad. Although the concentration is very low, it still causes great harm to the human body due to its physiological toxicity. Fluoroquinolone antibiotics are widely used as a broad-spectrum antibacterial antibiotic. Lomefloxacin (LOM), one of the most common fluoroquinolone antibiotics, has been detected in rivers and river basins in China, posing a great threat to human health.

[0003] The main technologies for removing LOM from water bodies include physical methods, chemical methods, and biodegradation methods. However, some traditional treatment technologies are subject to certain restrictions due to their complex processes, high operating costs, unstable effects, and the possibility of causing secondary pollution.

[0004] Compared with other treatment technologies, the persulfate advanced oxidation technology based on sulfate radicals has the characteristics of strong oxidation ability, long half-life, and wider pH range, and can degrade antibiotics into low-toxic or non-toxic substances. Permonosulfate (PMS) is easier to activate than peroxydisulfate (PDS) and is widely used in the removal of LOM. Among the catalysts for activating PMS to remove LOM, transition metal oxides have attracted widespread attention due to their low cost and simple operation. The single electron transfer of transition metals such as silver, copper, iron, zinc, cobalt and manganese can be used to activate persulfate and produce sulfate radicals. Among these transition metals, cobalt and nickel have high catalytic activity in the activation of persulfate and are considered to be the best metal catalysts for activating persulfate. Sulfidation of cobalt and nickel can accelerate the transfer between electrons and improve the activity of PMS. However, due to the easy agglomeration of metal ion nanoparticles, metal leaching, poor recyclability and ultimately easy to cause secondary pollution, the development of transition metals in the activation of persulfate is limited.

[0005] Nickel foam (NF) has outstanding advantages, such as three-dimensional (3D) network structure, low price, high specific surface area and volume, and abundant available electroactive sites. It has attracted wide attention in applications such as lithium-ion batteries, energy storage and catalysis. However, nickel foam (NF) is rarely used in activating PMS to remove antibiotics. Therefore, in view of the low activation effect of existing catalysts, easy agglomeration, high ion dissolution and poor recovery performance, if nickel foam can be combined with transition metals, can a more efficient, safe and environmentally friendly catalyst be obtained to activate PMS to degrade and remove antibiotics in water. Summary of the invention

[0006] The primary purpose of the present invention is to provide a cobalt-nickel composite material (Co3S4 / Ni3S2@NF composite material) based on nickel foam.

[0007] Another object of the present invention is to provide a method for preparing the above-mentioned Co3S4 / Ni3S2@NF composite material.

[0008] Another object of the present invention is to provide an application of the above-mentioned Co3S4 / Ni3S2@NF composite material in the treatment of antibiotic wastewater, aiming to solve the various deficiencies existing in the prior art in the above-mentioned background technology.

[0009] The present invention is achieved by a method for preparing a cobalt-nickel composite material with nickel foam as a substrate, the method comprising the following steps:

[0010] (1) pre-treating the nickel foam NF to remove oxides and impurities in the nickel foam;

[0011] (2) mixing cobalt salt, nickel salt and sodium thiosulfate in deionized water to obtain a precursor solution; wherein the molar volume ratio of the cobalt salt, nickel salt, sodium thiosulfate and deionized water is 1.48 mmol: 1.45-1.50 mmol: 2.3-2.4 mmol: 25-35 mL;

[0012] (3) Adding the pretreated nickel foam to the precursor solution, reacting at 138-142° C. for 5-7 hours, cooling to room temperature, washing, and drying to obtain a cobalt-nickel composite material Co3S4 / Ni3S2@NF based on nickel foam.

[0013] Preferably, in step (1), the pretreatment is specifically to ultrasonically treat the nickel foam NF with acetone, 12 mol / L hydrochloric acid and ethanol solution in sequence, each for 10 minutes, then ultrasonically treat it with deionized water three times, each for 5 minutes, and then dry the nickel foam in a vacuum oven at 80°C for 12 hours to obtain the pretreated nickel foam.

[0014] Preferably, in step (2), the cobalt salt is cobalt nitrate hexahydrate or cobalt nitrate.

[0015] Preferably, in step (2), the nickel salt is nickel nitrate hexahydrate or nickel nitrate.

[0016] Preferably, in step (2), a piece of 2*2 cm 2 Pre-treated nickel foam.

[0017] Preferably, in step (2), the washing and drying are: washing repeatedly with deionized water and then drying at 60° C. for 12 h.

[0018] Preferably, the loading mass of Co3S4 / Ni3S2 on NF in the Co3S4 / Ni3S2@NF is 9 mg / cm 2 .

[0019] The present invention further discloses a cobalt-nickel composite material Co3S4 / Ni3S2@NF with nickel foam as a substrate obtained by the above preparation method.

[0020] The present invention further discloses the application of the cobalt-nickel composite material Co3S4 / Ni3S2@NF based on nickel foam in activating persulfate to degrade antibiotics in water.

[0021] Preferably, the antibiotic comprises a fluoroquinolone antibiotic.

[0022] The present invention overcomes the deficiencies of the prior art and provides a cobalt-nickel composite material Co3S4 / Ni3S2@NF based on nickel foam, and a preparation method and application thereof. Nickel foam (NF) has outstanding advantages, such as a three-dimensional (3D) network structure, low price, high specific surface area and volume, and abundant available electroactive sites. It has attracted widespread attention in applications such as lithium-ion batteries, energy storage, and catalysis; however, it is rarely used in activating PMS to remove antibiotics. On this basis, the present invention successfully prepared Co3S4 / Ni3S2@NF by a one-step hydrothermal method, which is grown in situ from nickel foam and can be used to activate PMS to efficiently degrade LOM.

[0023] In the preparation method of the present invention, nickel foam is used as a substrate, which promotes the transfer efficiency of electrons and holes, solves the problem that the composite material is not easy to recycle, effectively inhibits the dissolution of metal ions, and improves the cycle stability of the composite material. In addition, nickel foam not only solves the problem of catalyst recovery as a metal carrier, but also provides a partial nickel source and participates in the catalytic reaction.

[0024] Compared with the shortcomings and deficiencies of the prior art, the present invention has the following beneficial effects:

[0025] (1) The preparation process of the composite material of the present invention is simple, easy to operate, low in cost, pollution-free, and suitable for large-scale production;

[0026] (2) The present invention is the first to load Co3S4 / Ni3S2@NF on nickel foam and generate highly active free radicals (SO4· - , OH, O2 - , 1 O2) can achieve 90.2% efficient removal of LOM within 60 minutes. At the same time, it still has a good removal effect on LOM after 4 cycles of reaction and effectively inhibits the dissolution of metal ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the XRD pattern of Co3S4 / Ni3S2@NF of the present invention;

[0028] Figure 2 This is a graph comparing the degradation effects of different systems of Co3S4 / Ni3S2@NF in the embodiment of the present invention;

[0029] Figure 3 This is a diagram showing the cycle effect of Co3S4 / Ni3S2@NF in an embodiment of the present invention.

[0030] Figure 4 This is the ion dissolution diagram of Co3S4 / Ni3S2@NF in the embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] Example 1

[0033] (1) treating the nickel foam with acetone, 12 mol / L hydrochloric acid and ethanol solution in sequence (10 minutes each time), and then treating the nickel foam with deionized water for three times (5 minutes each time); thereafter, drying the nickel foam in a vacuum oven at 80° C. for 12 hours to obtain a pretreated nickel foam;

[0034] (2) dissolving 1.48 mmol of cobalt nitrate hexahydrate (Co(NO3)2·6H2O), 1.48 mmol of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and 2.36 mmol of sodium thiosulfate (Na2S2O3) in 30 mL of deionized water and stirring for 20 minutes to mix the solution evenly, thereby obtaining a precursor solution;

[0035] (3) Transfer the above precursor solution into a 50 mL autoclave and add 2*2 cm 2 The pretreated nickel foam (thickness of 1 mm) was reacted at 140°C for 6 h, naturally cooled to room temperature, repeatedly washed with deionized water, and finally dried at 60°C for 12 h to obtain the Co3S4 / Ni3S2@NF composite material 1.

[0036] The loading mass of Co3S4 / Ni3S2@NF composite 1 on NF is about 9 mg / cm 2 (The loading amount was determined by taking the average difference between the NF weighings before and after the hydrothermal reaction).

[0037] The Co3S4 / Ni3S2@NF composite material 1 was observed, and the results were as follows Figure 1 As shown, the diffraction peaks in the XRD pattern of Co3S4 / Ni3S2@NF were analyzed by jade software. Compared with the standard cards of the materials, obvious characteristic peaks of different materials can be seen, proving the successful preparation of Co3S4 / Ni3S2@NF composite materials.

[0038] Example 2

[0039] (1) treating the nickel foam with acetone, 12 mol / L hydrochloric acid and ethanol solution in sequence (10 minutes each time), and then treating the nickel foam with deionized water for three times (5 minutes each time); thereafter, drying the nickel foam in a vacuum oven at 80° C. for 12 hours to obtain a pretreated nickel foam;

[0040] (2) dissolving 1.48 mmol of cobalt nitrate, 1.45 mmol of nickel nitrate and 2.3 mmol of sodium thiosulfate (Na2S2O3) in 35 mL of deionized water and stirring for 20 minutes to mix the solution evenly to obtain a precursor solution;

[0041] (3) Transfer the above precursor solution into a 50 mL autoclave and add 2*2 cm 2 The pretreated nickel foam (thickness of 1 mm) was reacted at 138°C for 5 h, naturally cooled to room temperature, repeatedly washed with deionized water, and finally dried at 60°C for 12 h to obtain the Co3S4 / Ni3S2@NF composite material 2.

[0042] Example 3

[0043] (1) treating the nickel foam with acetone, 12 mol / L hydrochloric acid and ethanol solution in sequence (10 minutes each time), and then treating the nickel foam with deionized water for three times (5 minutes each time); thereafter, drying the nickel foam in a vacuum oven at 80° C. for 12 hours to obtain a pretreated nickel foam;

[0044] (2) dissolving 1.48 mmol of cobalt nitrate, 1.50 mmol of nickel nitrate and 2.4 mmol of sodium thiosulfate (Na2S2O3) in 25 mL of deionized water and stirring for 20 minutes to mix the solution evenly to obtain a precursor solution;

[0045] (3) Transfer the above precursor solution into a 50 mL autoclave and add 2*2 cm 2 The pretreated nickel foam (thickness of 1 mm) was reacted at 142 °C for 7 h, naturally cooled to room temperature, repeatedly washed with deionized water, and finally dried at 60 °C for 12 h to obtain the Co3S4 / Ni3S2@NF composite material 3.

[0046] Application Example 1

[0047] 0.3g / L PMS, 0.5*0.5cm 2 NF (thickness 1mm) and 0.5*0.5cm 2 The Co3S4 / Ni3S2@NF composite material 1 was Figure 2 The grouped experimental system shown in the figure was that each system was added into a 200-mL conical flask containing 100 mL of LOM solution (10 mg / L, pH=6.75). The conical flask was placed in a constant temperature oscillating reactor at a rotation speed of 200 rpm and a temperature of room temperature. At a predetermined time interval, 2 mL of the reaction solution was collected, filtered through a 0.22 μm membrane, and the concentration change of LOM at the maximum absorption wavelength of 283 nm was immediately detected by a UV-visible spectrophotometer.

[0048] The results are as follows Figure 2As shown, it can be seen that in 0.5*0.5cm 2 In the presence of Co3S4 / Ni3S2@NF and 0.3 g / L PMS, the removal rate of LOM was 90.2% within 60 min. However, under the reaction conditions of only PMS, NF, and Co3S4 / Ni3S2@NF, the concentration of LOM remained basically unchanged, indicating that Co3S4 / Ni3S2@NF has an efficient removal effect on LOM by activating PMS.

[0049] Application Example 2

[0050] The stability of the material was investigated by repeated cyclic degradation experiments. In the cyclic experiments, the used Co3S4 / Ni3S2@NF was rinsed with deionized water and then dried at 60°C overnight for the next reaction.

[0051] The results are as follows Figure 3 As shown, it can be seen that although the catalytic efficiency of Co3S4 / Ni3S2@NF decreases slightly after each cycle, after 4 consecutive cycles, nearly 83.4% of LOM are still removed within 60 min, and Co3S4 / Ni3S2@NF has an excellent reuse effect.

[0052] Application Example 3

[0053] In order to study the dissolution of metal ions in the catalytic reaction system, the solutions after the catalytic degradation reaction in Application Examples 1 and 2 were tested using a high-resolution plasma optical emission spectrometer (ICP-OES). Figure 4 As shown, only a small amount of Co ions are leached out, and the Co ion leaching amount before and after the cycle reaction (0.160 and 0.138 mg / L) is lower than the standard (1 mg / L) of the "China Copper-Nickel-Cobalt Industry Pollutant Emission Standard" (GB25467-2010). This shows that the composite material is green, low-toxic and environmentally friendly.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Application of cobalt-nickel composite material Co3S4 / Ni3S2@NF based on nickel foam in activating persulfate to degrade antibiotics in water, characterized in that: The antibiotics include fluoroquinolone antibiotics. The preparation method of the cobalt-nickel composite material based on nickel foam comprises the following steps: (1) pre-treating the nickel foam NF to remove oxides and impurities in the nickel foam; (2) mixing cobalt salt, nickel salt and sodium thiosulfate in deionized water to obtain a precursor solution; wherein the molar volume ratio of the cobalt salt, nickel salt, sodium thiosulfate and deionized water is 1.48 mmol: 1.45-1.50 mmol: 2.3-2.4 mmol: 25-35 mL; (3) Adding the pretreated nickel foam to the precursor solution, reacting at 138-142° C. for 5-7 hours, cooling to room temperature, washing, and drying to obtain a cobalt-nickel composite material Co3S4 / Ni3S2@NF based on nickel foam.

2. The use according to claim 1, characterized in that In step (1), the pretreatment is specifically to ultrasonically treat the nickel foam NF with acetone, 12 mol / L hydrochloric acid and ethanol solution in sequence, each for 10 minutes, and then ultrasonically treat it with deionized water three times, each for 5 minutes, and then dry the nickel foam in a vacuum oven at 80° C. for 12 hours to obtain the pretreated nickel foam.

3. The use according to claim 1, characterized in that In step (2), the cobalt salt is cobalt nitrate hexahydrate or cobalt nitrate.

4. The use according to claim 1, characterized in that In step (2), the nickel salt is nickel nitrate hexahydrate or nickel nitrate.

5. The use according to claim 1, characterized in that In step (2), add a 2*2 cm 2 Pre-treated nickel foam.

6. The use according to claim 1, characterized in that In step (2), the washing and drying are as follows: washing repeatedly with deionized water and then drying at 60° C. for 12 hours.

7. The use according to claim 1, characterized in that The loading mass of Co3S4 / Ni3S2 on NF in the Co3S4 / Ni3S2@NF is 9 mg / cm 2 .

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