A carbon-based catalyst, a preparation method and application thereof

Abstract

The application provides a carbon-based catalyst and a preparation method and application thereof, and belongs to the technical field of wastewater treatment. The carbon material is activated to obtain an activated material; the activated material is mixed with phenol-containing wastewater, and then solid-liquid separation is performed; the obtained solid is calcined to obtain a carrier precursor; the carrier precursor, an iron salt and water are mixed, and then the pH value is adjusted to 10-11, and then reaction is performed to obtain a precipitate; the iron salt comprises Fe 2+ and Fe 3+ ; and the precipitate is dried to obtain the carbon-based catalyst. The carbon-based catalyst is prepared from the phenol-containing wastewater, the treatment amount of the phenol-containing wastewater is increased, the prepared carbon-based catalyst is used for treating the phenol-containing wastewater again, and catalytic degradation of phenolic substances is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, and particularly relates to a carbon-based catalyst and a preparation method and application thereof. BACKGROUND

[0002] Organic wastewater is a kind of widely existing water pollutants. Due to large discharge volume, deep color, complex composition, great toxicity and difficult biodegradation, the organic wastewater has become one of the key environmental pollution sources. Phenolic compounds in the organic wastewater are toxic to all organisms. Phenol can react with human skin and mucous membrane to form insoluble proteins, so that the cells lose vitality. High-concentration phenol solution can also cause protein coagulation. Phenolic substances discharged into water can cause great harm to water bodies and organisms therein. The phenol-containing wastewater mainly comes from coking plants, gas plants, petroleum chemical plants and insulating material plants. Reducing the content of phenolic substances in the phenol-containing wastewater can greatly reduce the damage and pollution of the phenol-containing wastewater to the environment

[0003] The most commonly used treatment methods at present include biological methods, physical methods and chemical methods. Although the conventional biological method has low treatment cost, the treatment process is slow, the land occupation is large and the discharge standard of the effluent cannot be guaranteed; the adsorption technology in the physical method is one of the simplest and most efficient methods for removing pollutants, but the adsorption material is difficult to desorb after adsorption, has low reuse rate and is difficult to separate; although the homogeneous Fenton oxidation method in the chemical method has simple operation and fast reaction rate, the Fenton reagent has large consumption, iron ions are easy to lose, the colority of water is increased, a large amount of iron sludge is generated, the catalyst cannot be recycled and utilized, and the operation cost is high.

[0004] The phenol-containing wastewater treatment agents disclosed in the prior art, such as Chinese patents CN103435115A, CN106673208A and CN102241802A, all have problems of low treatment efficiency of the phenol-containing wastewater, introduction of new organic substances and secondary pollution, and how to treat the phenol-containing wastewater at low cost and high efficiency is a pressing problem at present. SUMMARY

[0005] In view of this, the present application aims to provide a carbon-based catalyst and a preparation method and application thereof. The present application prepares a carbon-based catalyst from phenol-containing wastewater, and then uses the carbon-based catalyst for catalytic degradation of the phenol-containing wastewater, so as to treat the phenol-containing wastewater at low cost and high efficiency.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0007] The present application provides a preparation method of a carbon-based catalyst, comprising the following steps:

[0008] activating the carbon material to obtain an activated material;

[0009] Mixing the activated material with the phenol-containing wastewater, and then separating the solid from the liquid, and calcining the obtained solid to obtain a carrier precursor;

[0010] Mixing the carrier precursor, an iron salt and water, adjusting the pH value to 10-11, and then reacting to obtain a precipitate; the iron salt includes Fe 2+ and Fe 3+ ;

[0011] Drying the precipitate to obtain the carbon-based catalyst.

[0012] Preferably, the use amount ratio of the activated material to the phenol-containing wastewater is 1g:100-400mL, and the content of the phenolic substance in the phenol-containing wastewater is 100-2000mg / L.

[0013] Preferably, the phenolic substance includes one or more of phenol, cresol and dimethyl phenol.

[0014] Preferably, the carbon material includes a coal-based carbon material and / or a biochar, the coal-based carbon material includes one or more of coke, semi-coke and coal gangue, and the biochar includes one or more of wheat straw, rice husk, walnut shell, coconut shell, corn cob and banana peel; when the carbon material includes the coal-based carbon material and the biochar, the mass ratio of the coal-based carbon material to the biochar is 1:0.2-0.6.

[0015] Preferably, the activation includes the following steps: mixing the carbon material with potassium hydroxide, and then performing an activation treatment in an inert gas, the temperature of the activation treatment is 300-600℃, and the time is 1-3h.

[0016] Preferably, the calcination is performed in an inert gas, the temperature of the calcination is 300-500℃, and the time is 1-2h.

[0017] Preferably, the mass ratio of the carrier precursor to the iron salt is 1:0.5-1.2, and the molar ratio of Fe 2+ and Fe 3+ in the iron salt is 3:4-6.

[0018] Preferably, the temperature of the drying is 40-60℃, the pressure is 0.05-0.08MPa, and the time is 2-4h.

[0019] The application further provides a carbon-based catalyst prepared by the preparation method.

[0020] The application further provides an application of the carbon-based catalyst in treating phenol-containing wastewater, including the following steps:

[0021] Mixing the phenol-containing wastewater with the carbon-based catalyst to perform catalytic degradation.

[0022] The application provides a preparation method of a carbon-based catalyst, comprising the following steps: activating a carbon material to obtain an activated material; mixing the activated material with phenol-containing wastewater, and then performing solid-liquid separation, and calcining the obtained solid to obtain a carrier precursor; mixing the carrier precursor, an iron salt and water, adjusting the pH value to 10-11, and then reacting to obtain a precipitate; the iron salt comprises Fe 2+ and Fe 3+ ; and drying the precipitate to obtain the carbon-based catalyst.

[0023] The carbon-based catalyst is prepared from the phenol-containing wastewater, the treatment amount of the phenol-containing wastewater is increased, and the prepared carbon-based catalyst is used for treating the phenol-containing wastewater again, so that the catalytic degradation of phenolic substances is realized. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is an SEM photo of the carbon-based catalyst prepared in Example 1;

[0025] Figure 2 It is an EDS element diagram of the carbon-based catalyst prepared in Example 1;

[0026] Figure 3 It is an abundance diagram of each element;

[0027] Figure 4 It is an XRD spectrum diagram of the carbon-based catalyst prepared in Example 1;

[0028] Figure 5 It is a Raman spectrum diagram of the carbon-based catalyst prepared in Example 1;

[0029] Figure 6 It is an FT-IR spectrum diagram of the carbon-based catalyst prepared in Example 1;

[0030] Figure 7 It is an XPS energy spectrum diagram of the carbon-based catalyst prepared in Example 1, wherein (A) is a full spectrum diagram, (B) is a C energy spectrum diagram, (C) is an O energy spectrum diagram, and (D) is an Fe energy spectrum diagram;

[0031] Figure 8 It is a degradation kinetics curve of the carbon-based catalyst prepared in Example 1;

[0032] Figure 9 It is an effect diagram of the carbon-based catalyst prepared in Example 1 catalyzing the degradation of coking phenol-containing wastewater;

[0033] Figure 10 It is a GC-MS diagram of coking phenol-containing wastewater before and after the catalytic degradation of the coking phenol-containing wastewater by the carbon-based catalyst prepared in Example 1. DETAILED DESCRIPTION

[0034] The application provides a preparation method of a carbon-based catalyst, comprising the following steps:

[0035] activating a carbon material to obtain an activated material;

[0036] mixing the activated material with phenolic wastewater, performing solid-liquid separation, calcining the obtained solid to obtain a carrier precursor;

[0037] mixing the carrier precursor, an iron salt and water, adjusting the pH value to 10-11, and then performing reaction to obtain a precipitate; the iron salt comprises Fe 2+ and Fe 3+ ;

[0038] drying the precipitate to obtain the carbon-based catalyst.

[0039] In the application, the raw materials used are commercially available products in the art unless otherwise specified.

[0040] The application activates a carbon material to obtain an activated material.

[0041] In the application, the carbon material preferably comprises a coal-based carbon material and / or a biochar; the coal-based carbon material preferably comprises one or more of coke, semi-coke and coal gangue; and the biochar preferably comprises one or more of wheat straw, rice husk, walnut shell, coconut shell, corn cob and banana peel; when the carbon material preferably comprises a coal-based carbon material and a biochar, the mass ratio of the coal-based carbon material to the biochar is preferably 1:0.2-0.6.

[0042] In the application, the activation preferably comprises the following steps: mixing the carbon material with potassium hydroxide and performing activation treatment in an inert gas; the temperature of the activation treatment is preferably 300-600 ℃, more preferably 400-500 ℃; and the time is preferably 1-3 h.

[0043] In the application, the amount of potassium hydroxide used is preferably 0.5-1.2 wt% of the carbon material.

[0044] After obtaining the activated material, the application mixes the activated material with phenolic wastewater, performs solid-liquid separation, calcines the obtained solid to obtain a carrier precursor.

[0045] In the application, the calcination is preferably performed in an inert gas; the temperature of the calcination is preferably 300-500 ℃, more preferably 350-450 ℃; and the time is preferably 1-2 h.

[0046] In the application, the amount ratio of the activated material to the phenolic wastewater is preferably 1 g:100-300 mL; and the content of phenolic substances in the phenolic wastewater is preferably 100-2000 mg / L.

[0047] In the present application, the COD concentration of the phenol-containing wastewater is preferably 100-2100 mg / L, and the colority is preferably 200-1500 times.

[0048] In the present application, the phenol-containing wastewater is preferably from coking wastewater, petrochemical wastewater or organic wastewater.

[0049] In the present application, the phenolic substances preferably include one or more of phenol, cresol and dimethyl phenol.

[0050] In the present application, the mixing time is preferably 1-2 h, and the mixing is preferably stirring.

[0051] In the present application, the mixing is preferably followed by standing.

[0052] In the present application, during the mixing, the graphene-like substance, carbonyl group, aldehyde group and hydroxyl group in the activated material react with the phenolic substances in the wastewater to solidify and form carbon-based phenolic substances.

[0053] In the present application, the solid-liquid separation is preferably centrifugation.

[0054] After obtaining the carrier precursor, the present application mixes the carrier precursor, iron salt and water, adjusts the pH value to 10-11, and then reacts to obtain a precipitate; the iron salt includes Fe 2+ and Fe 3+ .

[0055] In the present application, the mass ratio of the carrier precursor to the iron salt is preferably 1:0.5-1.2, and more preferably 1:0.8-1.0, and the molar ratio of Fe 2+ and Fe 3+ in the iron salt is preferably 3:4-6, and more preferably 3:4.5-5.

[0056] In the present application, the iron salt is preferably a mixture of ferric chloride and ferrous chloride, a mixture of ferric chloride and ferrous sulfate, a mixture of ferric sulfate and ferrous chloride, or a mixture of ferric sulfate and ferrous sulfate.

[0057] In the present application, NaOH, KOH or ammonia water is preferably used to adjust the pH value to 10-11. In a specific embodiment of the present application, NaOH solution is preferably used, and the concentration of the NaOH solution is preferably 0.2 mol / L.

[0058] In the present application, during the reaction, the iron element forms C-Fe or C-O-Fe structure with the unsaturated bond (such as grapheme-like ring, carbonyl, aldehyde group, hydroxyl group) on the carrier precursor (carbon-based material), and then the iron element in the C-Fe or C-O-Fe structure is used as the core for the growth of Fe3O4 crystal, and finally the carbon-based catalyst with nano Fe3O4 loaded on the carbon-based material is formed.

[0059] In the present application, the reaction temperature is preferably 40-60℃, the reaction time is preferably 1-3h, and the reaction is preferably carried out in a nitrogen atmosphere.

[0060] In the present application, after the reaction is completed, a black suspension is preferably obtained, and the black suspension is preferably left to stand for 5-10min, and then washed with deionized water and anhydrous ethanol alternately until neutral to obtain the precipitate.

[0061] After the precipitate is obtained, the precipitate is dried to obtain the carbon-based catalyst.

[0062] In the present application, the drying temperature is preferably 40-60℃, the pressure is preferably 0.05-0.08MPa, and the time is preferably 2-4h.

[0063] The present application also provides the carbon-based catalyst prepared by the preparation method of the above technical solution.

[0064] In the present application, the carbon-based catalyst is a multi-layered carbon-based material with rich carbonyl or hydroxyl groups, and the surface of the multi-layered carbon-based material is loaded with Fe3O4, and the Fe3O4 is uniformly distributed in the form of cubic crystal or inlaid in the coupled biomass and phenol.

[0065] The present application also provides the application of the carbon-based catalyst of the above technical solution in treating phenol-containing wastewater.

[0066] In the present application, the application preferably comprises the following step: mixing the phenol-containing wastewater with the carbon-based catalyst for catalytic degradation.

[0067] In the present application, the phenol-containing wastewater is preferably consistent with the above solution, and will not be repeated here.

[0068] In the present application, the dosage ratio of the phenol-containing wastewater to the carbon-based catalyst is preferably 1000mL:0.8g.

[0069] In the present application, the temperature of the catalytic degradation is preferably 15-40℃, more preferably 25℃, and the time is preferably 1-2h.

[0070] In the present application, the mixing preferably further adds hydrogen peroxide, and the content of hydrogen peroxide in the system during the catalytic degradation is preferably 3-8mmol / L.

[0071] To further illustrate the present invention, the carbon-based catalysts, their preparation methods, and applications provided by the present invention are described in detail below with reference to examples, but these should not be construed as limiting the scope of protection of the present invention.

[0072] Example 1

[0073] A method for preparing a carbon-based catalyst (Fe3O4 / carbon-based material) includes the following steps:

[0074] Coke material and wheat straw were mixed at a mass ratio of 1:0.2 to obtain a mixture. Then, 0.5% potassium hydroxide by mass of the mixture was added and mixed well. The mixture was then activated in an inert gas atmosphere (600℃, 1h) to obtain the activated material.

[0075] 1g of the activating material was added to 300mL of phenol-containing wastewater and stirred at 200rpm for 2h. Then, the mixture was centrifuged and the resulting solid was calcined (300℃, 2h) to obtain the carrier precursor. The phenol concentration in the phenol-containing wastewater was 500mg / L, the COD concentration was 400mg / L, and the color was 500 times.

[0076] After obtaining the carrier precursor, iron salt was added to the carrier precursor at a mass ratio of 1:0.5, followed by the addition of NaOH solution until the pH reached 10–11. The mixture was then reacted for 0.5 h under a nitrogen atmosphere at 60°C to obtain a black suspension. The iron salt was a mixture of ferric chloride and ferrous chloride, and the iron salt contained Fe... 2+ and Fe 3+ The molar ratio was 3:4. The black suspension was allowed to stand for 10 min, and the lower precipitate was removed. It was then washed alternately with deionized water and anhydrous ethanol until neutral, and dried at 60 °C and 0.08 MPa for 2 h to obtain the carbon-based catalyst with a yield of 95.62%.

[0077] The structure of the prepared carbon-based catalyst was characterized. For example... Figure 1 As shown in the SEM image, Fe3O4 cubic crystalline nanoparticles are uniformly distributed on the carbon-based material. Figure 2 The EDS surface scan elemental diagram shows that the carbon-based catalyst is mainly composed of C, O, and Fe; the abundance of each element is shown in the figure. Figure 3 ;like Figure 4 The XRD pattern shows that the sample contains nano-Fe3O4 crystals; Figure 5 As shown, Raman spectroscopy reveals that carbon-based materials contain a very rich array of graphene-like structures; such as Figure 6 As shown, FT-IR further confirmed that these are absorption peaks of nano Fe3O4, and characteristic absorption peaks of carbon-based C=O, CO, and OH. Figure 7XPS spectra of the carbon-based catalyst, wherein (A) is a full spectrum, (B) is a C spectrum, (C) is an O spectrum, (D) is a Fe spectrum, further confirming that C-O, C=O, C-O-Fe, Fe 2+ 3+ characteristic binding energy peaks, the prepared carbon-based catalyst is Fe3O4 uniformly distributed in a cubic crystal morphology or inlaid in the coupled biomass and phenol, and has a multilayer carbon-based material with abundant carbonyl or hydroxyl groups.

[0078] The obtained carbon-based catalyst was used to characterize the degradation performance of phenol wastewater, as shown in Figure 8 the degradation kinetics curve of the carbon-based material, it was found that the prepared carbon-based material had good catalytic performance for phenol, and the degradation rate of phenol was as high as 100.00%.

[0079] The prepared carbon-based catalyst was added to the coking phenol-containing wastewater (the phenol concentration of the coking phenol-containing wastewater was 500 mg / L, the COD concentration was 400 mg / L, and the colority was 500 times) of a certain steel joint enterprise coking enterprise at 0.8 g / L, and stirred at 400 rpm for 2 h, at pH 6-9, hydrogen peroxide was 3 mmol / L, and the temperature was 25℃, to carry out catalytic degradation, Figure 9 the effect of the carbon-based material on the catalytic degradation of the coking phenol-containing wastewater, Figure 10 the GC-MS graphs of the coking phenol-containing wastewater before and after the catalytic degradation of the carbon-based material, and the water quality indexes were COD, colority and phenol: the removal rate of COD was 86.25%, the removal rate of colority was 94.23%, and the removal rate of phenol was 99.97%. When the pH value was 7, the treated wastewater was 40 min, the COD decreased to 58 mg / L, the colority of the solution decreased to 30, and the phenol decreased to 0.10 mg / L; 50 min, the COD of the solution decreased to 55 mg / L, which was lower than the national standard for regenerated water quality (COD≤60 mg / L), the colority of the solution remained 30, which met the national standard for regenerated water quality (colority≤30), the phenol decreased to 0.09 mg / L, which met the national standard for pollutant discharge (volatile phenol≤0.10 mg / L).

[0080] Example 2

[0081] A preparation method of a carbon-based catalyst, comprising the following steps:

[0082] The coke material and the rice husk were mixed in a mass ratio of 1:0.3 to obtain a mixture, 0.72% of potassium hydroxide based on the mass fraction of the mixture was added and mixed, and then activated in an inert gas (300℃, 3h) to obtain the activated material.

[0083] ​The activated material 1 g was added to the phenol-containing wastewater 160 mL, stirred at 350 rpm for 1 h, and then centrifuged, and the obtained solid was calcined (500 ℃, 1 h) to obtain a carrier precursor, the phenol concentration in the phenol-containing wastewater was 600 mg / L, the COD concentration was 700 mg / L, and the colority was 800 times.

[0084] After obtaining the carrier precursor, the carrier precursor was added with the iron salt at a mass ratio of carrier precursor: mixed iron salt of 1:0.65, and then NaOH solution was added until the pH value was 10-11, and then the black suspension was obtained under the conditions of nitrogen atmosphere and 60 ℃ for 0.5 h, the iron salt was a mixture of ferric chloride and ferrous chloride, the molar ratio of Fe 2+ and Fe 3+ in the iron salt was 3:4.5, the black suspension was allowed to stand for 10 min, and the lower precipitate was taken out; then the precipitate was washed with deionized water and anhydrous ethanol alternately until neutral, and dried at 60 ℃ and 0.08 MPa for 2 h to obtain the carbon-based catalyst, and the yield was 96.35%.

[0085] The obtained carbon-based catalyst was added to the coking phenol-containing wastewater (the phenol concentration in the coking phenol-containing wastewater was 600 mg / L, the COD concentration was 700 mg / L, and the colority was 800 times) of an independent coking enterprise at 0.8 g / L, stirred at 400 rpm for 2 h, and catalytically degraded at pH 6-9, hydrogen peroxide of 3 mmol / L, and temperature of 25 ℃, and the water quality indexes of COD, colority, and phenol were detected: the removal rates of COD, colority, and phenol were 92.86%, 96.38%, and 99.99%, respectively. When the pH value was 7, the COD of the solution was reduced to 55 mg / L, the colority of the solution was reduced to 29, and the phenol was reduced to 0.08 mg / L after treating the wastewater for 40 min; the COD of the solution was reduced to 50 mg / L, which was lower than the national standard for regenerated water quality (COD≤60 mg / L), the colority of the solution remained 29, which met the national standard for regenerated water quality (colority≤30), and the phenol was reduced to 0.03 mg / L, which met the national standard for pollutant discharge (volatile phenol≤0.10 mg / L) after 50 min.

[0086] Example 3

[0087] A preparation method of a carbon-based catalyst, comprising the following steps:

[0088] The coke material was mixed with walnut shells at a mass ratio of 1:0.35 to obtain a mixture, and then 0.8% of the mass fraction of potassium hydroxide was added to the mixture and mixed, and then activated in an inert gas (300 ℃, 3 h) to obtain an activated material.

[0089] The activated material 1 g was added to the phenol-containing wastewater 200 mL, stirred at 350 rpm for 1 h, then centrifuged, and the obtained solid was calcined (500 ℃, 1 h) to obtain the carrier precursor, the phenol concentration in the phenol-containing wastewater was 800 mg / L, the COD concentration was 900 mg / L, and the colority was 900 times.

[0090] After obtaining the carrier precursor, the carrier precursor was added with the iron salt at a mass ratio of carrier precursor: mixed iron salt of 1:0.75, then NaOH solution was added until the pH value was 10-11, and then the reaction was carried out under the conditions of nitrogen atmosphere and 60 ℃ for 0.5 h to obtain a black suspension, the iron salt was a mixture of ferric chloride and ferrous chloride, the molar ratio of Fe 2+ and Fe 3+ in the iron salt was 3:4.8, the black suspension was allowed to stand for 10 min, and the lower precipitate was taken out; then the precipitate was washed with deionized water and anhydrous ethanol alternately until neutral, and dried at 60 ℃ and 0.08 MPa for 2 h to obtain the carbon-based catalyst, and the yield was 95.46%.

[0091] The obtained carbon-based catalyst was added to the coking phenol-containing wastewater (the phenol concentration in the coking phenol-containing wastewater was 800 mg / L, the COD concentration was 900 mg / L, and the colority was 900 times) of a new coal chemical enterprise at 0.8 g / L, stirred at 400 rpm for 2 h, and catalytically degraded at pH 6-9, hydrogen peroxide 3 mmol / L, and temperature 25 ℃, and the water quality indexes of COD, colority, and phenol were detected: the removal rates of COD, colority, and phenol were 94.11%, 96.78%, and 99.99%, respectively. When the pH value was 7, the COD of the solution was reduced to 57 mg / L, the colority of the solution was reduced to 29, and the phenol was reduced to 0.07 mg / L after treating the wastewater for 40 min; the COD of the solution was reduced to 53 mg / L, which was lower than the national standard for regenerated water quality (COD≤60 mg / L), the colority of the solution remained 29, which met the national standard for regenerated water quality (colority≤30), and the phenol was reduced to 0.02 mg / L, which met the national standard for pollutant discharge (volatile phenol≤0.10 mg / L) after 50 min.

[0092] Example 4

[0093] A preparation method of a carbon-based catalyst, comprising the following steps:

[0094] The coke material was uniformly mixed with the coconut shell at a mass ratio of 1:0.4 to obtain a mixture, then 0.95% of the mass fraction of potassium hydroxide was added to the mixture, and then the mixture was activated in an inert gas (300 ℃, 3 h) to obtain the activated material.

[0095] The activated material 1 g was added to the phenol-containing wastewater 240 mL, stirred at 350 rpm for 1 h, and then centrifuged, and the obtained solid was calcined (500°C, 1 h) to obtain a carrier precursor, the phenol concentration in the phenol-containing wastewater was 1200 mg / L, the COD concentration was 1200 mg / L, and the colority was 1000 times.

[0096] After obtaining the carrier precursor, the carrier precursor was added with the iron salt at a mass ratio of carrier precursor: mixed iron salt of 1:0.90, and then NaOH solution was added until the pH value was 10-11, and then the black suspension was obtained under the conditions of nitrogen atmosphere and 60°C for 0.5 h, the iron salt was a mixture of ferric chloride and ferrous chloride, the molar ratio of Fe 2+ and Fe 3+ in the iron salt was 3:5, the black suspension was allowed to stand for 10 min, and the lower layer precipitate was taken out; the precipitate was washed with deionized water and anhydrous ethanol alternately until neutral, and then dried at 60°C and 0.08 MPa for 2 h to obtain the carbon-based catalyst, and the yield was 95.89%.

[0097] The obtained carbon-based catalyst was added to the phenol-containing wastewater (the phenol concentration in the phenol-containing wastewater was 1200 mg / L, the COD concentration was 1200 mg / L, and the colority was 1000 times) of a certain coal tar plant at 0.8 g / L, stirred at 400 rpm for 2 h, and catalytically degraded at pH 6-9, hydrogen peroxide 3 mmol / L, and temperature 25°C, and the water quality indexes of COD, colority, and phenol were detected: the removal rates of COD, colority, and phenol were 95.25%, 97.21%, and 100.00% respectively. When the pH value was 7 and the wastewater was treated for 40 min, the COD of the solution was reduced to 59 mg / L, the colority of the solution was reduced to 28, and the phenol was reduced to 0.07 mg / L; when the wastewater was treated for 50 min, the COD of the solution was reduced to 57 mg / L, which was lower than the national standard for reclaimed water (COD≤60 mg / L), the colority of the solution was maintained at 28, which met the national standard for reclaimed water (colority≤30), and the phenol was reduced to 0.02 mg / L, which met the national standard for pollutant discharge (volatile phenol≤0.10 mg / L).

[0098] Example 5

[0099] A method for preparing a carbon-based catalyst, comprising the following steps:

[0100] The coke material was mixed with the corn cob at a mass ratio of 1:0.45 to obtain a mixture, and then 1.05% of the mass fraction of potassium hydroxide was added to the mixture, and then the mixture was activated in an inert gas (300°C, 3 h) to obtain an activated material.

[0101] The activated material 1 g was added to the phenol-containing wastewater 380 mL, stirred at 350 rpm for 1 h, and then centrifuged, and the obtained solid was calcined (500°C, 1 h) to obtain the carrier precursor, the phenol concentration in the phenol-containing wastewater was 1600 mg / L, the COD concentration was 1600 mg / L, and the colority was 1200 times.

[0102] After obtaining the carrier precursor, the iron salt was added to the carrier precursor at a mass ratio of carrier precursor: mixed iron salt of 1:1.15, and then NaOH solution was added to the pH value of 10-11, and then the black suspension was obtained under the conditions of nitrogen atmosphere and 60°C for 0.5 h, the iron salt was a mixture of ferric chloride and ferrous chloride, the molar ratio of Fe 2+ and Fe 3+ in the iron salt was 3:5.7, the black suspension was left to stand for 10 min, and the lower precipitate was taken out; then the deionized water and anhydrous ethanol were alternately washed to neutral, and dried at 60°C and 0.08 MPa for 2 h to obtain the carbon-based catalyst, and the yield was 96.43%.

[0103] The obtained carbon-based catalyst was added to the coking phenol-containing wastewater (the phenol concentration in the coking phenol-containing wastewater was 1600 mg / L, the COD concentration was 1600 mg / L, and the colority was 1200 times) of a certain city gas plant at 0.8 g / L, stirred at 400 rpm for 2 h, and catalytically degraded at pH 6-9, hydrogen peroxide 3 mmol / L, and temperature 25°C, and the water quality indexes of COD, colority, and phenol were detected: the removal rates of COD, colority, and phenol were 96.94%, 98.13%, and 100.00%, respectively. When the pH value was 7, the COD of the solution was reduced to 54 mg / L, the colority of the solution was reduced to 27, and the phenol was reduced to 0.06 mg / L after treating the wastewater for 40 min; the COD of the solution was reduced to 49 mg / L, which was lower than the national standard for regenerated water quality (COD≤60 mg / L), the colority of the solution was maintained at 27, which met the national standard for regenerated water quality (colority≤30), and the phenol was reduced to 0.01 mg / L, which met the national standard for pollutant discharge (volatile phenol≤0.10 mg / L) after 50 min.

[0104] Example 6

[0105] The coke material was mixed with the banana peel at a mass ratio of 1:0.6 to obtain a mixture, and then 1.20% of the mass fraction of potassium hydroxide was added to the mixture, and then activated in the inert gas (300°C, 3 h) to obtain the activated material.

[0106] Activated material 1 g was added to 400 mL of phenol-containing wastewater and stirred at 350 rpm for 1 h, then centrifuged, and the obtained solid was calcined (500°C, 1 h) to obtain a carrier precursor. The phenol concentration in the phenol-containing wastewater was 2000 mg / L, the COD concentration was 2100 mg / L, and the colority was 1500 times.

[0107] After obtaining the carrier precursor, iron salt was added to the carrier precursor at a mass ratio of carrier precursor: mixed iron salt of 1:1.2, and NaOH solution was added until the pH value was 10-11, then the black suspension was obtained under the conditions of nitrogen atmosphere and 60°C for 0.5 h. The iron salt was a mixture of ferric chloride and ferrous chloride, and the molar ratio of Fe 2+ and Fe 3+ was 3:6.0. The black suspension was allowed to stand for 10 min, and the lower precipitate was removed. The carbon-based catalyst was prepared by washing with deionized water and anhydrous ethanol alternately until neutral, and drying at 60°C and 0.08 MPa for 2 h, with a yield of 94.72%.

[0108] The carbon-based catalyst prepared was added to coking phenol-containing wastewater (phenol concentration 2000 mg / L, COD concentration 2100 mg / L, colority 1500 times) from a gas production plant at 0.8 g / L and stirred at 400 rpm for 2 h, and catalytic degradation was carried out at pH 6-9, hydrogen peroxide 3 mmol / L, and temperature 25°C. The water quality indexes were COD, colority, and phenol. The removal rates of COD, colority, and phenol were 97.62%, 98.13%, and 100.00%, respectively. When the pH value was 7, the COD of the solution decreased to 56 mg / L, the colority of the solution decreased to 28, and the phenol decreased to 0.05 mg / L after 40 min of treatment of the wastewater. After 50 min, the COD of the solution decreased to 50 mg / L, which was lower than the national standard for regenerated water quality (COD≤60 mg / L), the colority of the solution remained at 30, which met the national standard for regenerated water quality (colority≤30), and the phenol decreased to 0.01 mg / L, which met the national standard for pollutant discharge (volatile phenol≤0.10 mg / L).

[0109] Comparative Example 1

[0110] In this example, the carbon-based catalyst was prepared according to the method and process parameters of Example 1. The difference between this example and Example 1 was that the carbon-based catalyst was not prepared using phenol-containing wastewater in this example.

[0111] The yield of the catalyst prepared in this comparative example was 91.36%.

[0112] The catalyst was added into the coking phenol-containing wastewater (the concentration of phenol in the coking phenol-containing wastewater was 100 mg / L, the concentration of COD was 100 mg / L, and the colority was 200 times) of a coking enterprise of a certain steel and iron joint enterprise at 0.8 g / L under stirring at 400 rpm for 2 h, and catalytic degradation was carried out at pH 6-9, hydrogen peroxide was 3 mmol / L, and the temperature was 25°C. The results are shown in Table 1. The water quality indexes were COD, colority, and phenol. The removal rate of COD was 39.01%, the removal rate of colority was 85.03%, and the removal rate of phenol was 99.70%. When the pH was 7, the COD of the solution was reduced to 62 mg / L, the colority of the solution was reduced to 30, and the phenol was reduced to 0.60 mg / L after 40 min of treatment of the wastewater. After 50 min, the COD of the solution was reduced to 60 mg / L, which met the national standard for regenerated water quality (COD≤60 mg / L), the colority of the solution was maintained at 30, which met the national standard for regenerated water quality (colority≤30), and the phenol was reduced to 0.30 mg / L, which was higher than the national standard for pollutant discharge (volatile phenol≤0.10 mg / L).

[0113] Comparative Example 2

[0114] In this example, the carbon-based catalyst was prepared according to the method and process parameters of Example 1. The difference from Example 1 was that wheat straw was not used to prepare the carbon-based catalyst, and the yield was 93.78%.

[0115] The carbon-based catalyst was added into the coking phenol-containing wastewater (the concentration of phenol in the coking phenol-containing wastewater was 500 mg / L, the concentration of COD was 400 mg / L, and the colority was 500 times) of a coking enterprise of a certain steel and iron joint enterprise at 0.8 g / L under stirring at 400 rpm for 2 h, and catalytic degradation was carried out at pH 6-9, hydrogen peroxide was 3 mmol / L, and the temperature was 25°C. The water quality indexes were COD, colority, and phenol. The removal rate of COD was 83.75%, the removal rate of colority was 93.81%, and the removal rate of phenol was 99.88%. When the pH was 7, the COD of the solution was reduced to 70 mg / L, the colority of the solution was reduced to 36, and the phenol was reduced to 0.71 mg / L after 40 min of treatment of the wastewater. After 50 min, the COD of the solution was reduced to 65 mg / L, which was higher than the national standard for regenerated water quality (COD≤60 mg / L), the colority of the solution was reduced to 31, which was higher than the national standard for regenerated water quality (colority≤30), and the phenol was reduced to 0.60 mg / L, which was higher than the national standard for pollutant discharge (volatile phenol≤0.10 mg / L).

[0116] The above only describes the preferred embodiments of the present application, and does not limit the present application in any form. It should be noted that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing a carbon-based catalyst, characterized by, The method comprises the following steps: activating the carbon material to obtain an activated material; mixing the activated material with phenolic wastewater, and then performing solid-liquid separation, and calcining the obtained solid to obtain a carrier precursor; The carrier precursor, iron salt and water are mixed, the pH value is adjusted to 10-11, and then the reaction is carried out to obtain a precipitate; the iron salt includes Fe 2+ and Fe 3+ ; drying the precipitate to obtain the carbon-based catalyst; the activated material and the phenolic wastewater are used in a ratio of 1 g: 100-400 mL, and the content of phenolic substances in the phenolic wastewater is 100-2000 mg / L; the calcination is performed in an inert gas, the temperature of the calcination is 300-500 ℃, and the time is 1-2 h.

2. The production method according to claim 1, characterized by, The phenolic substances include one or more of phenol, cresol and dimethyl phenol.

3. The method of claim 1, wherein, The carbon material includes a coal-based carbon material and / or a biochar, the coal-based carbon material includes one or more of coke, semi-coke and coal gangue, and the raw material for preparing the biochar includes one or more of wheat straw, rice husk, walnut shell, coconut shell, corn cob and banana peel; when the carbon material includes the coal-based carbon material and the biochar, the mass ratio of the coal-based carbon material to the biochar is 1:0.2-0.

6.

4. The production method according to claim 1 or 3, characterized by, The activation includes the following steps: mixing the carbon material with potassium hydroxide, and then performing activation treatment in an inert gas, the temperature of the activation treatment is 300-600 ℃, and the time is 1-3 h.

5. The preparation method according to claim 1, characterized in that, The mass ratio of the carrier precursor to the iron salt is 1:0.5-1.2, and the molar ratio of Fe 2+ and Fe 3+ in the iron salt is 3:4-6.

6. The method of claim 1, wherein, The temperature of the drying is 40-60 ℃, the pressure is 0.05-0.08 MPa, and the time is 2-4 h.

7. The carbon-based catalyst prepared by the preparation method in any one of claims 1-6.

8. Use of the carbon-based catalyst according to claim 7 for the treatment of phenolic waste water, characterized in that, The method comprises the following steps: mixing the phenolic wastewater with the carbon-based catalyst to perform catalytic degradation.

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