Method for realizing resource utilization of phenol pollutants in water by using nickel-ruthenium hybrid electrocatalyst

Abstract

The application discloses a method for realizing resource utilization of phenol pollutants in water by using a nickel-ruthenium hybrid electrocatalyst, and belongs to the technical field of environmental electrocatalytic water treatment. The nickel-ruthenium hybrid electrocatalyst loaded on carbon cloth is prepared by using a simple two-step electrodeposition method, aiming at problems such as high energy consumption, high material consumption and high carbon emission of a traditional wastewater treatment mode. The catalyst has high stability and high selectivity, and can realize directional conversion of phenol pollutants in water into high-value p-benzoquinone under mild conditions, so as to simultaneously realize removal of the phenol pollutants in water and recovery of high-value-added chemicals. The application provides a new method for treatment and resource utilization of high-concentration phenol wastewater.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, and in particular relates to a method for resource recovery of phenol pollutants in water using a nickel-ruthenium hybrid electrocatalyst. Background Technology

[0002] The continuous development of modern industry has driven record-breaking GDP growth, but at the same time, industrial production processes have also generated large amounts of toxic and harmful industrial wastewater, the treatment of which has become one of the bottlenecks to the sustainable development of modern industry. High-concentration organic wastewater is the most common type of industrial wastewater. Due to its diverse types, high concentrations, high toxicity, and difficulty in biodegradation of organic pollutants, it has posed a serious threat to the ecological environment and human health, and is considered by many countries as one of the environmental problems urgently needing to be solved. For a long time, using technologies such as chemical oxidation to achieve efficient mineralization of organic pollutants in wastewater has been the main strategy for addressing these problems. However, traditional wastewater treatment models that only focus on the mineralization of toxic organic pollutants have limitations such as high energy consumption, high material consumption, and high carbon emissions, which are in stark contrast to the currently advocated green, low-carbon, and circular development model. To advance industrial wastewater treatment towards the goals of pollution reduction and carbon reduction, it is urgent to recycle and utilize high-concentration organic pollutants in industrial wastewater.

[0003] With the rapid development of modern chemical industries, the discharge of phenol-containing wastewater from industries such as petrochemicals, pharmaceuticals, oil refining, papermaking, phenolic resins, and coking has increased dramatically. Phenolic wastewater poses a serious threat to the ecological environment and human health, thus requiring treatment to meet relevant emission standards. Phenol is usually the most significant pollutant in phenol-containing wastewater, with concentrations reaching hundreds or even tens of thousands of milligrams per liter. Therefore, the recovery of phenol from wastewater has important implications for the development of a sustainable society. p-Benzoquinone, a common intermediate product in the degradation of phenols, is usually considered a byproduct due to its extremely low yield. In fact, p-benzoquinone is not only an important chemical raw material for industrial products such as bactericides and dyes, but also a potential electrode material for lithium-ion batteries due to its high theoretical specific capacity and voltage. These demands make the economic value of p-benzoquinone (~100,000 RMB / ton) significantly higher than that of phenol (~5,000 RMB / ton). Therefore, selectively converting phenol pollutants in wastewater into p-benzoquinone can simultaneously achieve the removal of phenol pollutants and the recovery of high-value chemicals.

[0004] Electrocatalytic synthesis technology ingeniously combines electrochemistry and organic synthesis processes, enabling the simple, efficient, and tunable construction of specific chemical bonds. This technology uses electrons as reagents, achieving redox reactions of organic compounds to generate target products through electron gain and loss, and is considered a representative of "green and sustainable" chemistry. To date, researchers have investigated and verified the feasibility of electrocatalytic oxidation of phenol to p-benzoquinone using electrode materials such as platinum, polyaniline, and boron-doped diamond. However, these reported electrocatalytic oxidation reactions are all carried out in non-aqueous media or under strong acid conditions, and the conversion rates of phenol (<60%) and the yields of p-benzoquinone (<50%) are generally low. Therefore, for the removal and resource utilization of phenol from wastewater, it is crucial to develop efficient, durable, and easily prepared electrode materials that can selectively convert phenol pollutants into p-benzoquinone at room temperature. Summary of the Invention

[0005] In view of this, the purpose of this invention is to propose a method for the resource recovery of phenol pollutants in water using a nickel-ruthenium hybrid electrocatalyst. The method is characterized by the design and preparation of a highly active nickel-ruthenium hybrid catalyst, which can simultaneously achieve the removal of phenol pollutants in water and the selective generation of high-value p-benzoquinone.

[0006] The specific technical solution for achieving the objective of this invention is as follows:

[0007] A method for resource recovery of phenol pollutants in water using a nickel-ruthenium hybrid catalyst includes the following steps:

[0008] Step 1: Dissolve nickel nitrate in a pure aqueous solution and stir magnetically until homogeneous; the concentration of nickel nitrate is 40.0~80.0 mmol / L.

[0009] Step 2: Dissolve ruthenium trichloride in dilute hydrochloric acid solution, stir magnetically until homogeneous, and set aside; wherein, the concentration of ruthenium trichloride is 0.5~2.0 mmol / L; the concentration of dilute hydrochloric acid is 0.1 mol / L;

[0010] Step 3: Using the solution obtained in Step 1 as the electrolyte, carbon cloth as the cathode, a nickel-carbon porous electrode is prepared by electrodeposition using a three-electrode system; wherein, the negative potential applied for electrochemical deposition is 0.5~1.0 V; the deposition time is 5~15 min; a titanium sheet is used as the counter electrode, and a silver / silver chloride electrode is used as the reference electrode;

[0011] Step 4: Using the solution obtained in Step 2 as the electrolyte and the nickel-carbon electrode obtained in Step 3 as the substrate, the nickel-ruthenium hybrid electrocatalyst supported on carbon cloth is prepared again by electrochemical deposition. The negative potential applied during electrochemical deposition is 0.2~0.6 V; the deposition time is 2~5 min; a titanium sheet is used as the counter electrode and a silver / silver chloride electrode is used as the reference electrode.

[0012] Step 5: Dissolve phenol and sodium sulfate in ultrapure water, stir magnetically until homogeneous, and label this as the anolyte; dissolve an equal amount of sodium sulfate in ultrapure water, stir magnetically until homogeneous, and label this as the catholyte; wherein, the concentration of phenol is 0.5~10.0 mmol / L; the concentration of sodium sulfate is 10~100 mmol / L; the initial pH of the anolyte and catholyte is 3.0~9.0, and the pH of the solution is adjusted by 0.1 mol / L sulfuric acid or 0.1 mol / L sodium hydroxide solution;

[0013] Step 6: Inject the anolyte and catholyte prepared in Step 5 into the anode chamber and cathode chamber of the H-type electrolytic cell, respectively; use the nickel-ruthenium carbon porous electrode prepared in Step 4 as the anode, and use a three-electrode system to carry out the electrocatalytic oxidation reaction;

[0014] Step 7: Continuously introduce argon gas into the anode chamber, apply a constant current, and start the electrocatalytic oxidation reaction of phenol. After a period of reaction, the selective conversion of phenol pollutants into high-value p-benzoquinone chemicals can be achieved. The constant current applied is 1~3mA, and the reaction time is 150 min.

[0015] Compared with other existing technologies, the present invention has the following advantages:

[0016] (1) The nickel-ruthenium hybrid catalyst used in this invention has a simple preparation process, high stability, and high selectivity for the oxidation of phenol pollutants.

[0017] (2) When using the novel electrocatalytic oxidation system constructed by the present invention to treat phenol pollutants in water, it can not only effectively avoid the limitations of high energy consumption, high material consumption and high carbon emissions of traditional electrocatalytic oxidation methods, but also achieve the effective recovery of high-value benzoquinone chemicals.

[0018] (3) The nickel-ruthenium hybrid catalyst prepared by the present invention can achieve higher phenol conversion rate and p-benzoquinone yield, and has high anti-interference ability, and can operate in complex water environment. Attached Figure Description

[0019] Figure 1 This is a spherical aberration transmission electron microscope image of the nickel-ruthenium carbon electrode in Example 1;

[0020] Figure 2 The graph shows a comparison of phenol removal and p-benzoquinone yield performance under different electrode conditions in Examples 1-3.

[0021] Figure 3 This is a graph showing the cyclic performance of the nickel-ruthenium carbon electrode in Example 1;

[0022] Figure 4This is a comparison chart of phenol removal and p-benzoquinone yield performance of Example 1 and Comparative Examples 2-4 under different initial pH conditions;

[0023] Figure 5 The graph shows the phenol removal and p-benzoquinone yield performance of Example 4 in actual wastewater. Detailed Implementation

[0024] To better understand the content of this invention, the technical solution of this invention is further described below through specific embodiments, comparative examples, and accompanying drawings. However, these embodiments do not limit the scope of protection of this invention.

[0025] Example 1

[0026] (1) Dissolve 60 mmol / L nickel nitrate in 100 mL of pure water, stir magnetically until homogeneous, and set aside for later use;

[0027] (2) Dissolve 1.5 mmol / L ruthenium trichloride in 100 mL of 0.1 mol / L dilute hydrochloric acid solution, stir magnetically until homogeneous, and set aside for later use;

[0028] (3) The solution obtained in step 1 is used as the electrolyte, carbon cloth is used as the cathode, and a nickel-carbon porous electrode is prepared by electrodeposition using a three-electrode system; wherein, the negative potential applied for electrochemical deposition is 1.0 V; the deposition time is 10 min; a titanium sheet is used as the counter electrode, and a silver / silver chloride electrode is used as the reference electrode.

[0029] (4) Using the solution obtained in step 2 as the electrolyte and the nickel-carbon electrode obtained in step 3 as the substrate, the nickel-ruthenium hybrid electrocatalyst loaded on the carbon cloth was prepared again by electrochemical deposition. The negative potential applied during electrochemical deposition was 0.5 V, the deposition time was 3 min, and a titanium sheet was used as the counter electrode and a silver / silver chloride electrode was used as the reference electrode.

[0030] (5) Dissolve 0.5 mmol / L phenol and 100 mmol / L sodium sulfate in 50 mL of ultrapure water, stir magnetically until homogeneous, and label it as the anolyte; dissolve an equal amount of sodium sulfate in ultrapure water, stir magnetically until homogeneous, and label it as the catholyte; the initial pH of the anolyte and catholyte is 7.0, and the reagent for adjusting the pH of the solution is 0.1 mol / L sulfuric acid solution;

[0031] (6) The anolyte and catholyte prepared in step 5 are injected into the anode chamber and cathode chamber of the H-type electrolytic cell, respectively; the nickel-ruthenium carbon porous electrode prepared in step 4 is used as the anode, and the electrocatalytic oxidation reaction is carried out using a three-electrode system;

[0032] (7) Argon gas was continuously introduced into the anode chamber and a constant current of 2 mA was applied to start the electrocatalytic oxidation reaction of phenol. After 150 min of reaction, the selective conversion efficiency of phenol pollutants to high-value p-benzoquinone chemicals was evaluated.

[0033] Aberration transmission electron microscopy (TEM) image of the nickel-ruthenium-carbon porous electrode prepared in Example 1 is shown below. Figure 1 As shown. By Figure 2 The results showed that using a nickel-ruthenium carbon porous electrode, 96.5% of phenol in water could be removed within 150 min, while the yield of benzoquinone reached 83.4%. This indicates that the electrocatalytic oxidation system using nickel-ruthenium carbon as the anode can simultaneously achieve phenol removal and the selective formation of high-value-added benzoquinone under ambient conditions. Furthermore, the catalytic activity of the nickel-ruthenium carbon electrode was not significantly inhibited after five cycles, indicating its high stability. Figure 3 ).

[0034] Example 2

[0035] (1) Dissolve 60 mmol / L nickel nitrate in 100 mL of pure water, stir magnetically until homogeneous, and set aside for later use;

[0036] (2) The solution obtained in step 1 was used as the electrolyte, carbon cloth was used as the cathode, and a nickel-carbon porous electrode was prepared by electrodeposition using a three-electrode system; wherein, the negative potential applied for electrochemical deposition was 1.0 V; the deposition time was 10 min; a titanium sheet was used as the counter electrode, and a silver / silver chloride electrode was used as the reference electrode.

[0037] (3) Dissolve 0.5 mmol / L phenol and 100 mmol / L sodium sulfate in 50 mL of ultrapure water, stir magnetically until homogeneous, and label it as the anolyte; dissolve an equal amount of sodium sulfate in ultrapure water, stir magnetically until homogeneous, and label it as the catholyte; the initial pH of the anolyte and catholyte is 7.0, and the reagent for adjusting the pH of the solution is 0.1 mol / L sulfuric acid solution;

[0038] (4) The anolyte and catholyte prepared in step 3 are injected into the anode chamber and cathode chamber of the H-type electrolytic cell, respectively; the nickel-carbon porous electrode prepared in step 2 is used as the anode, and the three-electrode system is used for electrocatalytic oxidation reaction;

[0039] (5) Argon gas was continuously introduced into the anode chamber and a constant current of 2 mA was applied to start the electrocatalytic oxidation reaction of phenol. After 150 min of reaction, the selective conversion efficiency of phenol pollutants to high-value p-benzoquinone chemicals was evaluated.

[0040] Depend on Figure 2It can be seen that when using a nickel-carbon electrode as the anode, 73.7% of phenol in water can be removed within 150 min, but the yield of p-benzoquinone is only 16.1%, showing that the nickel catalyst has no selectivity for the catalytic oxidation of phenol to p-benzoquinone.

[0041] Example 3

[0042] (1) Dissolve 1.5 mmol / L ruthenium trichloride in 100 mL of 0.1 mol / L dilute hydrochloric acid solution, stir magnetically until homogeneous, and set aside for later use;

[0043] (2) The solution obtained in step 1 was used as the electrolyte, carbon cloth was used as the cathode, and a nickel-carbon porous electrode was prepared by electrodeposition using a three-electrode system; wherein, the negative potential applied for electrochemical deposition was 0.5 V; the deposition time was 3 min; a titanium sheet was used as the counter electrode, and a silver / silver chloride electrode was used as the reference electrode.

[0044] (3) Dissolve 0.5 mmol / L phenol and 100 mmol / L sodium sulfate in 50 mL of ultrapure water, stir magnetically until homogeneous, and label it as the anolyte; dissolve an equal amount of sodium sulfate in ultrapure water, stir magnetically until homogeneous, and label it as the catholyte; the initial pH of the anolyte and catholyte is 7.0, and the reagent for adjusting the pH of the solution is 0.1 mol / L sodium hydroxide solution;

[0045] (4) The anolyte and catholyte prepared in step 3 are injected into the anode chamber and cathode chamber of the H-type electrolytic cell, respectively; the ruthenium carbon porous electrode prepared in step 2 is used as the anode, and the three-electrode system is used to carry out the electrocatalytic oxidation reaction.

[0046] (5) Argon gas was continuously introduced into the anode chamber and a constant current of 2 mA was applied to start the electrocatalytic oxidation reaction of phenol. After 150 min of reaction, the selective conversion efficiency of phenol pollutants to high-value p-benzoquinone chemicals was evaluated.

[0047] Depend on Figure 2 It was found that when using a ruthenium-carbon electrode as the anode, 59.3% of phenol in water could be removed within 150 min, but the yield of p-benzoquinone was only 43.7%, with a selectivity of 73.7%. This indicates that the ruthenium catalyst has selectivity for the catalytic oxidation of phenol to p-benzoquinone, but its phenol conversion rate and p-benzoquinone yield are still relatively low. Compared with the catalytic performance of the nickel-ruthenium-carbon electrode, it was found that the introduction of nickel can promote the directional conversion of phenol to p-benzoquinone by the ruthenium-carbon electrode.

[0048] Comparative Example 1

[0049] The difference between this comparative example and Example 1 is that the initial pH of the two electrolytes in step (5) was adjusted to 3.0 using a 0.1 mol / L hydrochloric acid solution.

[0050] Comparative Example 2

[0051] The difference between this comparative example and Example 1 is that the initial pH of the two electrolytes in step (5) was adjusted to 5.0 using a 0.1 mol / L hydrochloric acid solution.

[0052] Comparative Example 3

[0053] The difference between this comparative example and Example 1 is that the initial pH of the two electrolytes in step (5) was adjusted to 9.0 using a 0.1 mol / L sodium hydroxide solution.

[0054] The removal of phenol and the yield of p-benzoquinone in the electrocatalytic oxidation systems of Examples 1 and Comparative Examples 1-3 under different initial pH conditions are as follows: Figure 5 As shown in the figure. The results show that the nickel-ruthenium carbon electrode can achieve the directional conversion of phenol to p-benzoquinone over a wide pH range.

[0055] Example 4

[0056] (1) Dissolve 60 mmol / L nickel nitrate in 100 mL of pure water, stir magnetically until homogeneous, and set aside for later use;

[0057] (2) Dissolve 1.5 mmol / L ruthenium trichloride in 100 mL of 0.1 mol / L dilute hydrochloric acid solution, stir magnetically until homogeneous, and set aside for later use;

[0058] (3) The solution obtained in step 1 is used as the electrolyte, carbon cloth is used as the cathode, and a nickel-carbon porous electrode is prepared by electrodeposition using a three-electrode system; wherein, the negative potential applied for electrochemical deposition is 1.0 V; the deposition time is 10 min; a titanium sheet is used as the counter electrode, and a silver / silver chloride electrode is used as the reference electrode.

[0059] (4) Using the solution obtained in step 2 as the electrolyte and the nickel-carbon electrode obtained in step 3 as the substrate, the nickel-ruthenium hybrid electrocatalyst loaded on the carbon cloth was prepared again by electrochemical deposition. The negative potential applied during electrochemical deposition was 0.5 V, the deposition time was 3 min, and a titanium sheet was used as the counter electrode and a silver / silver chloride electrode was used as the reference electrode.

[0060] (5) Label 50 mL of actual coking wastewater containing 10.0 mmol / L phenol as the anolyte; dissolve 100 mmol / L sodium sulfate in 50 mL of ultrapure water, stir magnetically until homogeneous, and label it as the catholyte; the initial pH of the anolyte and catholyte is 7.0, and the reagent for adjusting the pH of the solution is 0.1 mol / L sodium hydroxide solution;

[0061] (6) The anolyte and catholyte prepared in step 5 are injected into the anode chamber and cathode chamber of the H-type electrolytic cell, respectively; the nickel-ruthenium carbon porous electrode prepared in step 4 is used as the anode, and the electrocatalytic oxidation reaction is carried out using a three-electrode system;

[0062] (7) Argon gas was continuously introduced into the anode chamber and a constant current of 2 mA was applied to start the electrocatalytic oxidation reaction of phenol. After 150 min of reaction, the selective conversion efficiency of phenol pollutants to high-value p-benzoquinone chemicals was evaluated.

[0063] Example 4: Electrocatalytic oxidation efficiency of phenol in actual coking wastewater as follows Figure 5 As shown in the figure. The results indicate that the electrocatalytic oxidation system using nickel-ruthenium carbon as the anode can achieve a phenol removal rate of 68.1% within 24 h, and the yield of p-benzoquinone can reach 52.3%. This performance demonstrates that the electrocatalyst of this invention has good application prospects in the resource utilization of phenol-containing wastewater.

[0064] As can be seen from the above embodiments, the present invention provides a method for selectively converting phenol in water to p-benzoquinone using electrocatalytic oxidation. The method of the present invention can not only achieve the effect of purifying wastewater, but also simultaneously realize the recovery of high-value-added organic resources.

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for resource recovery of phenol pollutants in water using a nickel-ruthenium hybrid electrocatalyst, characterized in that, Includes the following steps: Step 1: Dissolve nickel nitrate in a pure aqueous solution, stir magnetically until homogeneous, and set aside; wherein the concentration of nickel nitrate is 40.0~80.0 mmol / L; Step 2: Dissolve ruthenium trichloride in dilute hydrochloric acid solution, stir magnetically until homogeneous, and set aside; wherein, the concentration of ruthenium trichloride is 0.5~2.0 mmol / L; the concentration of dilute hydrochloric acid is 0.1 mol / L; Step 3: Using the solution obtained in Step 1 as the electrolyte, carbon cloth as the cathode, a nickel-carbon porous electrode is prepared by electrodeposition using a three-electrode system; wherein, the negative potential applied for electrochemical deposition is 0.5~1.0 V; the deposition time is 5~15 min; a titanium sheet is used as the counter electrode, and a silver / silver chloride electrode is used as the reference electrode; Step 4: Using the solution obtained in Step 2 as the electrolyte and the nickel-carbon electrode obtained in Step 3 as the substrate, the nickel-ruthenium hybrid electrocatalyst supported on carbon cloth is prepared again by electrochemical deposition. The negative potential applied during electrochemical deposition is 0.2~0.6 V; the deposition time is 2~5 min; a titanium sheet is used as the counter electrode and a silver / silver chloride electrode is used as the reference electrode. Step 5: Dissolve phenol and sodium sulfate in ultrapure water, stir magnetically until homogeneous, and label this as the anolyte; dissolve an equal amount of sodium sulfate in ultrapure water, stir magnetically until homogeneous, and label this as the catholyte; wherein, the concentration of phenol is 0.5~10.0 mmol / L; the concentration of sodium sulfate is 10~100 mmol / L; the initial pH of the anolyte and catholyte is 3.0~9.0, and the pH of the solution is adjusted by 0.1 mol / L sulfuric acid or 0.1 mol / L sodium hydroxide solution; Step 6: Inject the anolyte and catholyte prepared in Step 5 into the anode chamber and cathode chamber of the H-type electrolytic cell, respectively; use the nickel-ruthenium carbon porous electrode prepared in Step 4 as the anode, and use a three-electrode system to carry out the electrocatalytic oxidation reaction; Step 7: Continuously introduce argon gas into the anode chamber, apply a constant current, and start the electrocatalytic oxidation reaction of phenol. After a period of reaction, the selective conversion of phenol pollutants into high-value p-benzoquinone chemicals can be achieved. The constant current applied is 1~3 mA, and the reaction time is 150 min.

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