Application of carbon fiber nanomaterial in removing nitrate ions

Abstract

The application discloses application of carbon fiber nanometer material in removal of nitrate ions, and is divided into the following steps: first, synthesizing tetra-para-acetylamino phenyl porphyrin; second, synthesizing tetra-para-acetylamino phenyl porphyrin cobalt; third, preparing a single-atom catalyst; fourth, performing SEM morphology characterization analysis on the single-atom nanometer material; fifth, performing electrochemical reaction and analysis; and finally, obtaining a conclusion that a monomer of the single-atom nanometer material is immobilized on the surface of carbon fiber by using in-situ deposition technology, the monomer catalyst has high catalytic activity corresponding to that of rhodium nanometer material, the price of the monomer catalyst is only about 1% of that of the rhodium nanometer material, the monomer catalyst is low in price, sewage treatment cost is reduced, and the monomer catalyst has wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of chemical experimental research technology, specifically to the application of carbon fiber nanomaterials in the removal of nitrate ions. Background Technology

[0002] In wastewater treatment, it is necessary to remove nitrate ions from the wastewater. Existing methods utilize rhodium-modified TiO2 nanorod arrays and then electrochemically remove nitrate ions. Experimental studies have shown that rhodium-modified nanomaterials have excellent electrochemical removal capabilities for nitrate ions. However, metallic rhodium is expensive and difficult to apply widely. Therefore, this invention provides an application of carbon fiber nanomaterials in the removal of nitrate ions. Summary of the Invention

[0003] The purpose of this invention is to provide an application of carbon fiber nanomaterials in the removal of nitrate ions, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an application of carbon fiber nanomaterials in the removal of nitrate ions, comprising the following steps:

[0005] S1): Synthesize tetra-p-acetaminophenylporphyrin;

[0006] S2): Synthesize cobalt tetra-p-acetaminophenylporphyrin;

[0007] S3): Preparation of single-atom catalysts;

[0008] S4): SEM morphology characterization analysis of single-atom nanomaterials;

[0009] S5): Electrochemical reactions and analysis;

[0010] S6): We have reached a conclusion.

[0011] Preferably, in step S2, during the synthesis of cobalt tetraacetaminophenylporphyrin, cobalt trichloride is added to a DMF solution containing tetraacetaminophenylporphyrin, refluxed, cooled, and then an equal or greater volume of hydrogen chloride solution is added. The mixture is then precipitated, filtered, and washed to prepare cobalt tetraacetaminophenylporphyrin.

[0012] Preferably, in step S3, during the preparation of the single-atom catalyst, tetraaminophenylporphyrin cobalt is dissolved in an acetonitrile solution containing tetrabutylaminohexafluorophosphate, the treated carbon fiber is used as the working electrode, silver-AgCl containing 0.1M silver nitrate is used as the reference electrode, and a platinum sheet electrode is used as the auxiliary electrode. Polytetraaminophenylporphyrin cobalt-modified carbon fiber nanomaterials are prepared by cyclic voltammetry.

[0013] Preferably, the synthesis of the corresponding single-atom nanomaterial precursor is carried out by electrochemical deposition technology, in which single-atom cobalt nanomaterials are immobilized on the surface of a support, which can be carbon fiber nanomaterials, and then single-atom catalytic nano-island activation centers are formed.

[0014] Preferably, in step S4, 20μm and 5μm single-atom nanomaterials are respectively immobilized on bare carbon cloth, carbon cloth with 4 turns, carbon cloth with 20 turns, and carbon cloth with 30 turns, and the distribution of the materials on the carbon cloth is analyzed and compared.

[0015] Preferably, in step S5, after preparing the modified electrode, the electrochemical reduction of nitrate is performed using the modified electrode, and glassy carbon electrode, carbon cloth, and nickel mesh are selected as electrode materials.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] This study investigated the removal of nitrate ions by carbon fiber nanomaterials. Through experiments, single-atom nanomaterial monomers were immobilized on the surface of carbon fibers using in-situ deposition technology. This single-atom catalyst exhibits high catalytic activity comparable to that of rhodium nanomaterials, but at only about 1% of the price. Its low cost reduces wastewater treatment costs and has broad application prospects.

[0018] This study investigated the removal of nitrate ions using carbon fiber nanomaterials. The single-atom nanocatalyst exhibits strong catalytic activity, numerous activation sites, and low cost, classifying it as a novel nanomaterial. It also demonstrates high selectivity, low catalyst dosage, high catalytic activity, and strong stability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating the synthesis of tetraacetamidophenylporphyrin according to the present invention.

[0020] Figure 2 This is a schematic diagram of the reaction between cobalt trichloride and p-tetraacetaminophenylporphyrin according to the present invention.

[0021] Figure 3 This is a SEM image of carbon fiber immobilized with single-atom nanomaterials according to the present invention, as well as schematic diagrams of 20μm and 5μm single-atom nanomaterials.

[0022] Figure 4 This is a SEM image of carbon fiber immobilized with single-atom nanomaterials according to the present invention, and a schematic diagram showing the distribution of 20μm and 5μm single-atom nanomaterials immobilized on bare carbon cloth, carbon cloth with 4 rings, carbon cloth with 20 rings, and carbon cloth with 30 rings.

[0023] Figure 5This is a schematic diagram of nitrate removal under light-shielding conditions with Rh doping concentrations of 1×10⁻³ (A), 8×10⁻⁴ (B), 7×10⁻⁴ (C), 6×10⁻⁴ (D), 5×10⁻⁴ (E), and 4×10⁻⁴ (F) (mol / L). Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example: Figure 1-5 The present invention provides a technical solution: the application of carbon fiber nanomaterials in the removal of nitrate ions, comprising the following steps:

[0026] S1): Synthesize tetra-p-acetaminophenylporphyrin;

[0027] S2): Synthesize cobalt tetra-p-acetaminophenylporphyrin;

[0028] S3): Preparation of single-atom catalysts;

[0029] S4): SEM morphology characterization analysis of single-atom nanomaterials;

[0030] S5): Electrochemical reactions and analysis;

[0031] S6): We have reached a conclusion.

[0032] The following is a schematic diagram illustrating the synthesis of tetraacetamidophenylporphyrin:

[0033] In S2, during the synthesis of cobalt tetraacetamidophenylporphyrin, cobalt trichloride is added to a DMF solution containing tetraacetamidophenylporphyrin, and the reaction is carried out at high temperature. (Reaction diagram follows.)

[0034] After reflux for 12 hours, the mixture was cooled and an equal or greater volume of hydrogen chloride solution was added. The precipitate was then filtered and washed to prepare tetraacetamidoporphyrin cobalt. The volume of the hydrogen chloride solution was 6M, and the reaction and reflux were carried out at high temperature.

[0035] In S3, during the preparation of the single-atom catalyst, tetraaminophenylporphyrin cobalt was dissolved in an acetonitrile solution containing tetrabutylaminohexafluorophosphate. The treated carbon fiber was used as the working electrode, silver-AgCl containing 0.1M silver nitrate as the reference electrode, and a platinum sheet electrode as the auxiliary electrode. Polytetraaminophenylporphyrin cobalt-modified carbon fiber nanomaterials were prepared using cyclic voltammetry. The corresponding single-atom nanomaterial precursor was synthesized, and the single-atom cobalt nanomaterials were immobilized on the surface of a support, which could be carbon fiber nanomaterials, using electrochemical deposition technology. This formed single-atom catalytic nanoisland activation centers, which were then used to study the electrochemical removal of nitrate ions from wastewater systems.

[0036] In S4, 20μm and 5μm single-atom nanomaterials were immobilized on bare carbon cloth, 4 turns of carbon cloth, 20 turns of carbon cloth, and 30 turns of carbon cloth, respectively. Analysis and comparison of the material distribution on the carbon cloth revealed that at the 20μm scale, the material distribution was not uniform, while at the 5μm scale, the material was essentially randomly packed. Further magnification of the SEM scanning scale showed that the rough surface of the material resulted in a superior specific surface area and more catalytic active centers, leading to the superior electrocatalytic activity of the carbon fibers modified with our single-atom nanomaterials. The figure below shows the SEM images of carbon fibers immobilized with single-atom nanomaterials and the distribution of 20μm and 5μm single-atom nanomaterials immobilized on bare carbon cloth, 4 turns of carbon cloth, 20 turns of carbon cloth, and 30 turns of carbon cloth.

[0037] Furthermore, in S5, after preparing the modified electrode, we used it for the electrochemical reduction of nitrate. We selected glassy carbon electrode, carbon cloth, and nickel mesh as electrode materials. Among them, the carbon cloth electrode was used to test the effect of different electropolymerization scan cycles on the catalytic activity of the modified electrode for nitrate reduction. From the figure above, we can clearly see that the bare carbon cloth electrode has no catalytic activity. The fewer the electropolymerization scan cycles, the faster the reaction rate is at the beginning of the reaction, but the reaction almost stops in the later stage. It is speculated that the electrode modification material has poor adsorption and the material falls off after a period of reaction, or that the voltage for electrolytic reduction of nitrate is too high, resulting in hydrogen evolution and thus material falling off. Therefore, we should find a more suitable electrode material or reduce the voltage for electrolytic reduction of nitrate. However, the carbon cloth electrode with 4 scan cycles stopped catalysis after about two hours. It is speculated that this may be because the polymerization time is short, the adsorption between the modification material and the electrode is poor, and the material falls off. Increasing the number of polymerization scans may lead to larger polymer molecules in the modified material, slowing down the external and internal diffusion rates of nitrate ions, resulting in a decrease in the reaction rate. Moreover, the carbon cloth electrode with 30 scans did not react in the first hour, which is presumably due to the long polymerization time causing the surface molecules to be too dense, or the activation of single-atom nanocatalysts leading to a decrease in electrochemical activity. Therefore, 20 scans are more suitable for carbon cloth electrodes.

[0038] Rhodium-doped titanium dioxide nanotube arrays catalyze the electrochemical reduction of nitrate. Under identical experimental conditions, it is evident that the single-atom nanomaterial-modified electrode achieves a maximum reduction of 42% in 6 hours, comparable to that of rhodium. However, cobalt is significantly cheaper than rhodium, effectively reducing the cost of electrochemical nitrate reduction. The diagrams illustrating nitrate removal under light-shielding conditions with Rh doping concentrations of 1×10⁻³ (A), 8×10⁻⁴ (B), 7×10⁻⁴ (C), 6×10⁻⁴ (D), 5×10⁻⁴ (E), and 4×10⁻⁴ (F) (mol / L) demonstrate this.

[0039] S6: In conclusion, existing technologies utilizing rhodium-modified TiO2 nanorod arrays and rhodium-modified TiO2 nanoarrays to study the electrochemical removal of nitrate ions demonstrate that rhodium-modified nanomaterials possess excellent electrochemical nitrate removal capabilities. However, metallic rhodium is expensive, hindering its widespread application. In-situ deposition technology can be used to immobilize single-atom nanomaterials onto the surface of carbon fibers. This single-atom catalyst exhibits high catalytic activity comparable to rhodium nanomaterials, but at only about 1% of the price, making it inexpensive, reducing wastewater treatment costs, and showing broad application prospects.

[0040] Working principle: The experimental study on the removal of nitrate ions by carbon fiber nanomaterials is divided into the following steps: First step, synthesis of tetra-p-acetaminophenylporphyrin; second step, synthesis of cobalt tetra-p-acetaminophenylporphyrin; third step, preparation of single-atom catalyst; fourth step, SEM morphology characterization and analysis of single-atom nanomaterials; fifth step, electrochemical reaction and analysis, and finally, conclusions are drawn.

[0041] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An application of carbon fiber nanomaterials in the removal of nitrate ions, characterized in that, Includes the following steps: S1): Synthesize tetra-p-acetaminophenylporphyrin; S2): To synthesize cobalt tetraaminophenylporphyrin, cobalt trichloride was added to a DMF solution containing tetraacetaminophenylporphyrin, refluxed for 12 h and then cooled. An equal volume or more of hydrogen chloride solution was added, and the precipitate was filtered and washed to prepare cobalt tetraaminophenylporphyrin. S3): Cobalt tetraaminophenylporphyrin was dissolved in an acetonitrile solution containing tetrabutylaminohexafluorophosphate. The treated carbon fiber was used as the working electrode, silver-AgCl containing 0.1M silver nitrate was used as the reference electrode, and a platinum sheet electrode was used as the auxiliary electrode. Cobalt tetraaminophenylporphyrin modified carbon fiber nanomaterials were prepared by cyclic voltammetry. S4): SEM morphology characterization analysis of cobalt-modified polytetraaminophenylporphyrin carbon fiber nanomaterials; S5): Electrochemical reaction and analysis: Electrochemical reduction of nitrate was performed using a modified electrode, with carbon cloth selected as the electrode material. S6): It is concluded that the material has high catalytic activity corresponding to that of rhodium nanomaterials.

2. The application of carbon fiber nanomaterials according to claim 1 in the removal of nitrate ions, characterized in that: In step S4, 20 μm and 5 μm polytetraaminophenylporphyrin cobalt-modified carbon fiber nanomaterials are respectively immobilized on bare carbon cloth, carbon cloth with 4 turns, carbon cloth with 20 turns, and carbon cloth with 30 turns, and the distribution of the material on the carbon cloth is analyzed and compared.

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