Paint slag derived activated carbon-coated cobalt nanomaterial and preparation method and application thereof

Abstract

The application provides a paint residue derived activated carbon coated cobalt nanomaterial and a preparation method and application thereof, the preparation method in the application uses solid hazardous waste paint residue as raw material, and adsorbs metal cobalt ions on the paint residue; the cobalt ion-paint residue compound is calcined and pyrolyzed, a magnetic Co-AC catalyst is obtained, and the catalyst is applied to catalytic activation of peroxymonosulfate to degrade new organic pollutants in water. The paint residue derived activated carbon coated cobalt nanomaterial in the application can be used as a green and efficient heterogeneous Fenton-like catalyst, peroxymonosulfate is activated through a non-free radical pathway, and the catalyst is easy to separate and reuse under an external magnetic field.

Description

Technical Field

[0001] This invention relates to the fields of nanomaterial preparation and water treatment technology, specifically to a cobalt nanomaterial coated with activated carbon derived from paint slag, its preparation method, and its application. Background Technology

[0002] With the development of technology, advanced oxidation (AOP) technology is increasingly favored in the water pollution treatment industry. It has the characteristics of high energy efficiency, high degree of automation and mild and safe operating environment, and is considered to be one of the best choices for treating complex organic wastewater.

[0003] With in-depth research into wastewater treatment technologies, many carbon nanomaterials have been used for persulfate (PMS) activation. Biomass-derived nanocarbons, in particular, have attracted widespread attention due to their simple synthesis methods and cost-effectiveness. Although various biomass-derived nanocarbons have been fabricated and applied in PS / PMS systems, the reactants produced and the potential mechanisms for pollutant removal remain poorly understood. Furthermore, the preparation of multifunctional nanocarbons remains challenging, especially when using recycled industrial solid waste as raw materials. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the main objective of this invention is to provide a cobalt-coated activated carbon nanomaterial derived from paint slag, its preparation method, and its application. The preparation method uses solid hazardous waste paint slag as raw material, adsorbing metallic cobalt ions onto the paint slag; then, the cobalt ion-paint slag composite is calcined and pyrolyzed to obtain a magnetic Co-AC catalyst, which is applied to the catalytic activation of persulfate (PMS) to degrade novel organic pollutants in water. The cobalt-coated activated carbon nanomaterial derived from paint slag in this invention can serve as a green and efficient heterogeneous Fenton-like catalyst, activating PMS via a non-radical pathway; and it is easily separated and reused under an external magnetic field.

[0005] To achieve the above objectives, the first aspect of the present invention provides a method for preparing cobalt nanomaterials coated with activated carbon derived from paint slag.

[0006] The preparation method of the cobalt nanomaterial coated with activated carbon derived from paint slag includes the following steps:

[0007] Obtain paint residue powder;

[0008] The paint residue powder is soaked in an immersion solution containing cobalt ions and then ground to obtain a mixture.

[0009] The mixture is dried to obtain a cobalt ion-paint residue composite.

[0010] The cobalt ion-paint slag composite was pyrolyzed under a protective atmosphere, and the nanomaterial was obtained after cooling.

[0011] Furthermore, the soaking solution is a solution containing CoCl2;

[0012] Preferably, the soaking solution further includes an ethanol solution;

[0013] Preferably, the concentration of cobalt ions in the soaking solution is 0.8–1.5 mol / L.

[0014] Furthermore, the paint residue powder is soaked in the soaking solution for 20 to 24 hours.

[0015] Furthermore, the temperature for drying the mixture is 0–200°C, preferably 50–60°C.

[0016] Furthermore, the pyrolysis includes a first pyrolysis stage and a second pyrolysis stage. The temperature of the first pyrolysis stage is 300–550°C, and the time is 2–5 hours. The temperature of the second pyrolysis stage is 500–1000°C, and the time is 1–3 hours.

[0017] Preferably, the protective atmosphere comprises nitrogen.

[0018] Furthermore, the temperature of the first pyrolysis stage is 400–550°C, and the time is 2 hours; the temperature of the second pyrolysis stage is 600–800°C, and the time is 1 hour.

[0019] Furthermore, the particle size of the paint residue powder is 5–15 μm.

[0020] Furthermore, the recovered paint residue is sequentially washed, dried, and ground to obtain the paint residue powder;

[0021] Preferably, the rinsing solution used includes an ethanol solution.

[0022] To achieve the above objectives, a second aspect of the present invention provides a cobalt nanomaterial coated with activated carbon derived from paint slag.

[0023] Paint slag-derived activated carbon-coated cobalt nanomaterials were prepared using the preparation method provided in the first aspect of this invention.

[0024] To achieve the above objectives, a third aspect of the present invention provides an application of cobalt nanomaterials coated with activated carbon derived from paint slag.

[0025] Application of cobalt-coated activated carbon nanomaterials derived from paint slag prepared by the preparation method provided in the first aspect of the present invention or cobalt-coated activated carbon nanomaterials derived from paint slag provided in the second aspect of the present invention in the degradation of organic pollutants in water.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. The cobalt nanomaterial Co-AC, derived from paint slag, has a wide pH range and high tolerance to anions and various types of actual polluted water.

[0028] 2. The activated carbon-coated cobalt nanomaterial Co-AC derived from paint slag in this invention is magnetic, easy to recycle using an external magnet, has significant stability, reusability in degrading organic pollutants, and still maintains high degradation efficiency.

[0029] 3. The activated carbon-coated cobalt nanomaterial Co-AC derived from paint slag in this invention can serve as an economical and efficient nanocatalyst, generating economic and environmental benefits in the practical field of wastewater treatment. Attached Figure Description

[0030] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. In the drawings:

[0031] Figure 1 A schematic diagram illustrating the preparation process of Co-AC, an activated carbon-coated cobalt nanomaterial derived from paint slag, in an embodiment of the present invention.

[0032] Figure 2 Scanning electron microscope (SEM) image of Co-AC nanomaterials coated with activated carbon derived from paint slag in the embodiments provided by the present invention;

[0033] Figure 3 In the embodiments provided by the present invention, let me look at the transmission electron microscope image of the cobalt nanomaterial Co-AC coated with activated carbon derived from paint slag.

[0034] Figure 4 The Co-AC / PMS system's degradation effect on different pollutants is shown in the embodiments provided by this invention.

[0035] Figure 5 The effect of catalyst dosage on TCH degradation in the Co-AC / PMS system provided in the embodiments of the present invention;

[0036] Figure 6 The effect of pH on TCH degradation in the Co-AC / PMS system provided in the embodiments of the present invention;

[0037] Figure 7 The diagram shows the cyclic degradation effect of Co-AC nanomaterials coated with activated carbon derived from paint slag in the embodiments provided by the present invention. Detailed Implementation

[0038] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0039] This invention utilizes a method of co-combustion with lignite to treat paint slag, transforming it into a valuable catalyst. Due to the presence of various metal species and abundant organic components, paint slag can serve as a potential raw material for preparing carbon-supported metal catalysts.

[0040] In this invention, a Co catalyst supported on activated carbon was prepared using paint slag and Co ions as raw materials. The resulting paint slag-derived activated carbon-coated cobalt nanomaterial, Co-AC, served as a multifunctional heterogeneous catalyst for the PMS-activated degradation of tetracycline hydrochloride. The reactants were identified using quenching experiments and electron paramagnetic resonance (EPR). Various in-situ characterization methods were employed to reveal the potential mechanism of the Co-AC / PMS catalytic system. The results show that the Co-AC / PMS system effectively and selectively oxidizes electron-rich organic pollutants via a non-radical pathway.

[0041] This invention not only proposes a new strategy for converting hazardous industrial solid waste into valuable catalysts, but also provides new ideas for the non-radical activation pathway of PMS.

[0042] The first aspect of the present invention provides a method for preparing cobalt nanomaterials coated with activated carbon derived from paint slag.

[0043] The preparation method of cobalt nanomaterials coated with activated carbon derived from paint slag in this invention is carried out according to the following steps.

[0044] 1) Obtain paint residue powder.

[0045] In an embodiment of the present invention, the recovered paint residue is sequentially washed, dried and ground to obtain paint residue powder.

[0046] The rinsing solution used includes an ethanol solution.

[0047] For example, the recovered paint residue is washed with water and ethanol solution, dried, and then ground into a fine powder for later use.

[0048] In an embodiment of the present invention, the particle size of the paint residue powder is 5-15 μm.

[0049] 2) Soak the paint residue powder in a soaking solution containing cobalt ions to obtain a mixture.

[0050] In an embodiment of the present invention, the soaking solution is a solution containing CoCl2.

[0051] For example, the soaking solution is a solution containing CoCl2·6H2O.

[0052] In embodiments of the present invention, the soaking solution also includes an ethanol solution.

[0053] For example, the ethanol solution uses anhydrous ethanol (99.5%).

[0054] In an embodiment of the present invention, the concentration of cobalt ions in the soaking solution is 0.8–1.5 mol / L.

[0055] For example, the soaking solution uses anhydrous ethanol as the solvent and cobalt ions as the solute, with a cobalt ion concentration of 0.8–1.5 mol / L.

[0056] For example, the amount of CoCl2·6H2O used in this invention is 0.005 to 0.15 g.

[0057] For example, the finely ground paint residue powder is thoroughly ground and soaked in a CoCl2·6H2O solution (1 mol / L ethanol).

[0058] In an embodiment of the present invention, the paint residue powder is soaked in the soaking solution for 20 to 24 hours, for example, for 24 hours.

[0059] 3) The mixture is dried to obtain a cobalt ion-paint residue composite.

[0060] In embodiments of the present invention, the temperature for drying the mixture is in the range of 0 to 200°C.

[0061] In some embodiments of the present invention, the drying temperature is in the range of 50 to 60°C, such as drying at 60°C.

[0062] 4) Under a protective atmosphere, the dried cobalt ion-paint sludge composite was pyrolyzed and cooled to obtain cobalt nanomaterials coated with activated carbon derived from paint sludge.

[0063] In an embodiment of the present invention, the pyrolysis temperature range is 200–1000°C, and the furnace is cooled to room temperature after pyrolysis is completed.

[0064] For example, the dried cobalt ion-paint residue composite is pyrolyzed in a tube furnace under an oxygen-free atmosphere, such as under a nitrogen atmosphere.

[0065] In an embodiment of the present invention, pyrolysis includes a first pyrolysis stage and a second pyrolysis stage, wherein the temperature of the first pyrolysis stage is 300-550°C and the time is 2-5 hours, for preliminary carbonization and dehydration; the temperature of the second pyrolysis stage is 500-1000°C and the time is 1-3 hours, for high-temperature carbonization.

[0066] In some embodiments of the present invention, the temperature of the first pyrolysis stage is 400-550°C and the time is 2 hours; the temperature of the second pyrolysis stage is 600-800°C and the time is 1 hour.

[0067] A second aspect of the present invention provides a cobalt nanomaterial coated with activated carbon derived from paint slag.

[0068] The cobalt nanomaterials coated with activated carbon derived from paint slag were prepared using the preparation method provided in the first aspect of this invention.

[0069] A third aspect of the present invention provides the application of cobalt nanomaterials coated with activated carbon derived from paint slag in the degradation of organic pollutants in water.

[0070] The cobalt nanomaterials coated with activated carbon derived from paint slag are prepared by the preparation method provided in the first aspect of the present invention or by the cobalt nanomaterials coated with activated carbon derived from paint slag provided in the second aspect of the present invention.

[0071] The following detailed description, through specific embodiments, illustrates the cobalt nanomaterials coated with activated carbon derived from paint slag, their preparation method, and their applications in this invention.

[0072] Example 1

[0073] Preparation of cobalt nanomaterials coated with activated carbon derived from paint slag:

[0074] (1) Pretreatment: The recovered paint residue is washed with water and ethanol solution, dried and ground into fine powder to obtain paint residue powder with a particle size of 5-15μm for later use.

[0075] (2) Grind the finely ground paint residue powder thoroughly in a CoCl2·6H2O solution (1 mol / L ethanol) and soak for 24 hours. The concentration of cobalt ions is 1 mol / L.

[0076] (3) The mixture was dried in a drying oven at 60°C to obtain a cobalt ion-paint residue composite.

[0077] (4) The dried cobalt ion-paint residue composite was pyrolyzed in a tube furnace under N2 atmosphere. The pyrolysis process included two stages in sequence, namely 550℃ for 2h and 800℃ for 1h. After cooling to room temperature, the black activated carbon-coated cobalt nanomaterial Co-AC was obtained.

[0078] Depend on Figure 1 It can be seen that the orange paint residue is transformed into black activated carbon during the pyrolysis process.

[0079] Figure 2 and Figure 3 Scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the cobalt nanomaterial Co-AC, which is derived from paint slag and coated with activated carbon, prepared in Example 1 are shown respectively. As can be seen from the images, the Co-AC catalyst exhibits a granular structure with abundant metal nanoparticles embedded on the surface of the activated carbon.

[0080] The present invention tested the degradation effect of cobalt nanomaterial Co-AC, derived from paint slag and coated with activated carbon, obtained in Example 1, on different pollutants. The results are as follows: Figure 4 As shown.

[0081] The specific experimental procedure was as follows: The pH of the reaction system (pH range 3–11) was adjusted by adding 0.1 mol / L HCl or 0.1 mol / L NaOH. A mixed suspension of 0.1 g / L Co-AC and 20 mg / L TCH was added to 30 mL of water and stirred for 60 min to establish adsorption-desorption equilibrium. Subsequently, while maintaining continuous stirring, 0.2 g / L PMS was added to the suspension. At specific time intervals, such as 5 min, 1.0 mL of the reaction mixture was withdrawn using a syringe and then mixed with 0.2 mL of methanol to stop the reaction. The solution and catalyst were separated by filtration, and the concentration of TCH in the solution was analyzed by high-performance liquid chromatography (HPLC). The degradation effect of the material on pollutants was then analyzed. After the experiment, the material used was filtered, collected, dried, and reused.

[0082] Figure 4 The results demonstrate the selectivity of Co-AC in degrading different pollutants, such as bisphenol A (BPA), ciprofloxacin (CIP), sulfamethoxazole (SMX), norfloxacin (NOR), nitrobenzene (NB), and benzoic acid (BA). The Co-AC / PMS system showed good degradation performance for electron-donating groups BPA, NOR, SMX, and CIP, but poor degradation performance for the free radical indicator BA and the electron-deficient group NB.

[0083] Clearly, the Co-AC / PMS system is more inclined to degrade electron-rich pollutants, further indicating the presence of non-radicals.

[0084] It is worth mentioning that the degradation of pollutants occurred under conditions of pH 7.0–7.5.

[0085] This invention investigated the effect of the amount of cobalt nanomaterials coated with activated carbon derived from paint slag prepared in Example 1 on the degradation of tetracycline hydrochloride (TCH) in the Co-AC / PMS system. The results are as follows: Figure 5 As shown.

[0086] Figure 5 The results show that when the Co-AC catalyst concentration is in the range of 0.01 to 0.4 g / L, the degradation rate of TCH reaches more than 99% within 20 min, and the degradation rate increases with the increase of catalyst dosage.

[0087] This invention investigated the effect of cobalt nanomaterials coated with activated carbon derived from paint slag prepared in Example 1 on the degradation of TCH under different pH conditions. The results are as follows: Figure 6 As shown.

[0088] Figure 6 This indicates that the Co-AC / PMS system exhibits excellent catalytic activity over a wide pH range of 3–11, which is of great significance in water treatment.

[0089] The present invention tested the recycling effect of the cobalt nanomaterials coated with activated carbon derived from paint slag prepared in Example 1, and the results are as follows: Figure 7 As shown.

[0090] Figure 7 The results show that the TCH degradation efficiency remained above 95% even after 10 consecutive catalytic oxidation cycles. This demonstrates the high stability and reusability of Co-AC in heterogeneous catalysis.

[0091] In summary, the Co-AC catalyst of this invention is applicable across a wide pH range and also exhibits a certain degradation effect on other pollutants in water. Even with increasing cycle counts, the removal rate of TCH remains above 95%. The Co-AC catalyst demonstrates excellent performance in degrading organic pollutants in water, showing promising prospects for practical application.

[0092] This invention not only transforms industrial hazardous waste into useful carbon catalytic materials, but also provides an economical and efficient method for the recycling and reuse of hazardous waste. Furthermore, it offers new ideas for the application of waste-derived catalysts in environmental remediation, achieving a balance between economic and environmental benefits.

[0093] It should be noted that the descriptions of "first," "second," etc., involved in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0094] Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0095] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing cobalt nanomaterials coated with activated carbon derived from paint slag that catalytically activates persulfate to degrade organic pollutants in water, characterized in that, Includes the following steps: Paint residue powder is obtained, wherein the particle size of the paint residue powder is 5~15μm; The paint residue powder is soaked in an immersion solution containing cobalt ions and then ground to obtain a mixture; the immersion solution also includes an ethanol solution, and the concentration of cobalt ions in the immersion solution is 0.8~1.5 mol / L; The mixture is dried to obtain a cobalt ion-paint residue composite. Under a protective atmosphere, the cobalt ion-paint slag composite is pyrolyzed, and after cooling, cobalt nanomaterials coated with activated carbon derived from the paint slag are obtained; wherein, the pyrolysis includes a first pyrolysis stage and a second pyrolysis stage, the temperature of the first pyrolysis stage is 300~550℃ and the time is 2~5h; the temperature of the second pyrolysis stage is 500~1000℃ and the time is 1~3h.

2. The preparation method according to claim 1, characterized in that, The soaking solution is a solution containing CoCl2.

3. The preparation method according to claim 1, characterized in that, The paint residue powder is soaked in the soaking solution for 20-24 hours.

4. The preparation method according to claim 1, characterized in that, The temperature for drying the mixture is 50~60℃.

5. The preparation method according to claim 1, characterized in that, The protective atmosphere includes nitrogen.

6. The preparation method according to claim 1, characterized in that, The temperature of the first pyrolysis stage is 400~550℃ and the time is 2h; the temperature of the second pyrolysis stage is 600~800℃ and the time is 1h.

7. The preparation method according to claim 1, characterized in that, The recovered paint residue is washed, dried, and ground in sequence to obtain the paint residue powder.

8. The preparation method according to claim 7, characterized in that, The rinsing solution used includes an ethanol solution.

9. A cobalt nanomaterial coated with activated carbon derived from paint slag, prepared by the preparation method according to any one of claims 1-8.

10. The application of the cobalt nanomaterials coated with activated carbon derived from paint slag as described in claim 9 in the catalytic activation of persulfate to degrade organic pollutants in water.

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