Oily sludge-based heterogeneous catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of solid waste resource utilization, and discloses an oily sludge-based heterogeneous catalyst as well as a preparation method and application thereof. The method comprises the following steps: (1) carrying out ball milling on zinc salt and oily sludge pyrolysis residues to obtain a ball-milled mixture; and (2) carbonizing the ball-milled mixture at 60-100 DEG C to obtain the oil-containing sludge-based heterogeneous catalyst, wherein the oily sludge pyrolysis residue contains 20 to 30 weight percent of Fe2O3 (ferric oxide) and 30 to 40 weight percent of Al2O3 (aluminum oxide). According to the method, the oily sludge pyrolysis residues containing the iron source and the aluminum source are mixed with the zinc salt, and the oily sludge-based heterogeneous catalyst is prepared under the mechanochemical action, so that the actual reaction activity of activated persulfate or Fenton is further improved, pollutants in water are rapidly and efficiently removed, and the purpose of treating waste with waste is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of resource utilization of solid waste, and particularly relates to an oil sludge-based heterogeneous catalyst, a preparation method thereof and an application thereof. Background Art

[0002] In recent years, advanced oxidation technology has received extensive attention as a technology for effectively degrading organic pollutants in wastewater. Among them, in the visible light-assisted Fenton system, hydroxyl radicals and superoxide radicals generated by the interaction of a heterogeneous catalyst and hydrogen peroxide can effectively decompose refractory organic pollutants and mineralize them completely. However, existing catalysts still have disadvantages such as complex synthesis routes, harsh preparation conditions, and high raw material costs. Therefore, it is particularly important to develop a heterogeneous photo-Fenton catalyst with high performance, low cost, good stability, and reusability.

[0003] Layered double hydroxides (LDHs), defined as natural or synthetic layered compounds, are called anionic minerals or hydrotalcite-like compounds. Due to characteristics such as chemical stability, high specific surface area, and flexible structure, they have become carriers and catalysts for many catalytic reactions. Because the abundant hydroxyl groups on the surface can provide a large number of hydroxyl active groups for catalytic reactions, they have been widely used in photocatalytic reactions.

[0004] All kinds of oil-containing sludge, such as floor oil sludge, refinery oil sludge, bottom oil sludge in tanks, and surface oil spills, are hazardous waste generated during oil exploration and refining. Due to their damage to the ecological environment, harm to human health, and restriction of sustainable development, they have gradually received attention, bringing increasing pressure to the environment. How to resourcefully utilize oil-containing sludge has attracted extensive attention. The sludge pyrolysis technology converts oily sludge into high-value energy products such as high-quality oil, combustible gas, and solid products that are easy to store, transport, have a high energy density, and are convenient to use through a continuous process and industrialized production method. Compared with conventional oxygen-consuming incineration technology, it has the advantages of less flue gas emissions and air pollutants, and effectively reducing greenhouse gas emissions. However, the pyrolysis residue still belongs to hazardous waste and needs further resource utilization.

[0005] In recent years, the preparation of composite catalytic materials using industrial solid waste as the main raw material has received extensive attention because it can simultaneously achieve two environmental goals: saving raw materials (including chemical reagents) and waste reuse.

[0006] CN108212164 B discloses a Fenton-like catalyst and a preparation method thereof. The Fenton-like catalyst is prepared from sludge pyrolysis carbon as a raw material and clay as a binder without adding an iron source or a transition metal source. The iron source is iron salts and iron oxides, and the transition metal source is salts of transition metals and transition metal oxides. The Fenton-like catalyst has a degradation efficiency of ≥80% for catalyzing the degradation of antibiotics in wastewater by hydrogen peroxide within the pH range of 2-10. On the one hand, sludge pyrolysis carbon is fully utilized as a raw material to prepare a Fenton-like catalyst with good performance, providing a new way for the high-value utilization of sludge pyrolysis carbon. On the other hand, the Fenton-like catalyst obtained by anaerobic calcination under a high-temperature protective atmosphere has high strength. The technical solutions disclosed in this patent mainly have the following problems: 1. Only the catalytic reaction of hydrogen peroxide is realized; 2. When wet ball milling is carried out, too much surface modifier is added, resulting in an increase in cost; 3. The temperature of sludge pyrolysis and calcined blank is relatively high; 4. A layered double hydroxide catalyst cannot be obtained.

[0007] It can be seen that in the prior art, when using sludge to prepare a heterogeneous catalyst, additives need to be added, the reaction temperature is relatively high, resulting in a relatively high cost; only the catalytic reaction of hydrogen peroxide can be realized; and a layered double hydroxide catalyst cannot be obtained. Therefore, there is an urgent need to provide a heterogeneous catalyst with a relatively low cost and capable of realizing the catalytic reaction of other peroxides. Summary of the Invention

[0008] The purpose of the present invention is to overcome the problems in the prior art that when preparing an oil-containing sludge-based heterogeneous catalyst, additives need to be added, the reaction temperature is relatively high, only the catalytic reaction of hydrogen peroxide can be realized, and a layered double hydroxide catalyst cannot be obtained. The present invention provides an oil-containing sludge-based heterogeneous catalyst, a preparation method thereof and an application. The present invention mixes an oil-containing sludge pyrolysis residue containing an iron source and an aluminum source with a zinc salt, and prepares an oil-containing sludge-based heterogeneous catalyst under the action of mechanochemistry, so as to further improve the reaction activity of activating persulfate or Fenton reagent, realize the rapid and efficient removal of pollutants in water, and achieve the purpose of "treating waste with waste".

[0009] To achieve the above purpose, on the one hand, the present invention provides a method for preparing an oil-containing sludge-based heterogeneous catalyst, and the method includes the following steps:

[0010] (1) Ball-mill a zinc salt and an oil-containing sludge pyrolysis residue to obtain a ball-milled mixture;

[0011] (2) Carbonize the ball-milled mixture at 60-100°C to obtain an oil-containing sludge-based heterogeneous catalyst;

[0012] Among them, the pyrolysis residue of the oily sludge contains 20-30 wt% of Fe2O3 and 30-40 wt% of Al2O3.

[0013] Preferably, in step (1), the weight ratio of the zinc salt to the pyrolysis residue of the oily sludge is 0.5-5:1, preferably 1-2:1.

[0014] Preferably, the residual carbon of the pyrolysis residue of the oily sludge burned at 500-600 °C is <1 wt%.

[0015] Preferably, step (1) specifically includes: dry-grinding the zinc salt and the pyrolysis residue of the oily sludge, and then wet-grinding.

[0016] Preferably, the conditions for dry-grinding include: the dry-grinding rate is 200-600 rmp, and the dry-grinding time is 4-6 h.

[0017] Preferably, the conditions for wet-grinding include: the wet-grinding rate is 200-600 rmp, and the wet-grinding time is 1-2 h.

[0018] Preferably, step (2) specifically includes: mixing the ball-milled mixture with the sodium carbonate solution and then carbonizing.

[0019] Preferably, the dosage ratio of the sodium carbonate solution to the pyrolysis residue of the oily sludge is 0.5-2 mL:1 g.

[0020] Preferably, the concentration of the sodium carbonate solution is 0.1-0.2 mol / L.

[0021] Preferably, in step (2), the conditions for carbonization include: the carbonization temperature is 60-100 °C, and the carbonization time is 1-2 h.

[0022] The second aspect of the present invention provides a heterogeneous catalyst based on oily sludge prepared by the method described above.

[0023] The third aspect of the present invention provides an application of the heterogeneous catalyst based on oily sludge described above as a heterogeneous Fenton catalyst.

[0024] The fourth aspect of the present invention provides a method for degrading organic matter in wastewater, which includes: reacting the heterogeneous catalyst based on oily sludge described above, peroxide and phenol-containing wastewater under visible light.

[0025] Preferably, the dosage ratio of the heterogeneous catalyst based on oily sludge, the peroxide and phenol in the phenol-containing wastewater is 1 g:0.01-0.1 mmol:0.005-0.05 mmol.

[0026] Preferably, the peroxide is hydrogen peroxide and / or persulfate.

[0027] Preferably, the phenol-containing wastewater is phenol wastewater.

[0028] Preferably, the concentration of phenol in the phenol wastewater is 5 - 15 mmol / L.

[0029] Preferably, the reaction time is 1 - 10 h.

[0030] The inventors of the present invention found that by using the pyrolysis residue of oily sludge containing iron salt and aluminum source and zinc salt as raw materials, only ball milling and low-temperature carbonization are required to prepare a heterogeneous catalyst based on oily sludge. Among them, the alkaline components (sodium oxide, calcium oxide) in the pyrolysis residue of oily sludge act as the necessary alkaline reagents for synthesizing the heterogeneous catalyst. The zinc salt and the aluminum source in the pyrolysis residue of oily sludge can form a Zn-Al double-layer skeleton, and the iron salt in the pyrolysis residue of oily sludge can form the active component Fe2O3 of the catalyst, thereby obtaining a heterogeneous catalyst with a special structure that can realize the catalytic reaction of peroxides other than persulfate and degrade phenolic pollutants.

[0031] Compared with the prior art, the present invention mainly has the following beneficial effects:

[0032] 1. The present invention uses the mechanical force activation method to prepare the catalyst, with simple process, high yield, low pollution and low cost;

[0033] 2. The present invention uses the pyrolysis residue of oily sludge as the raw material to prepare a heterogeneous catalyst, which is conducive to the effective utilization of the pyrolysis residue, reduces the generation of waste, and realizes the improvement of the comprehensive solidification efficiency;

[0034] 3. The preparation process of the present invention is simple, without adding other residual substances, and has a high waste utilization rate;

[0035] 4. The present invention makes full use of the abundant iron and aluminum elements in the pyrolysis residue, and has the advantages of low price and rich resources compared with the existing catalyst carriers;

[0036] 5. The heterogeneous catalyst prepared by the present invention can efficiently promote the decomposition of oxides such as persulfate, and realize the complete degradation of phenol-containing wastewater in groundwater and sewage treatment plants. Description of the Drawings

[0037] Figure 1 is a schematic flow chart of the heterogeneous catalyst based on oily sludge prepared in Example 1 of the present invention. Detailed Embodiments

[0038] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0039] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0040] The first aspect of the present invention provides a method for preparing an oil-containing sludge-based heterogeneous catalyst, and the method includes the following steps:

[0041] (1) Ball-milling a zinc salt and an oil-containing sludge pyrolysis residue to obtain a ball-milled mixture;

[0042] (2) Carbonizing the ball-milled mixture at 60-100 °C to obtain an oil-containing sludge-based heterogeneous catalyst.

[0043] The present invention uses specific oil-containing sludge pyrolysis residue and zinc salt as raw materials, and only needs to be ball-milled and low-temperature carbonized to obtain an oil-containing sludge-based heterogeneous catalyst. The process is simple, has little pollution, low cost, and low waste utilization rate.

[0044] In the present invention, the oil-containing sludge pyrolysis residue is obtained by treating with a conventional sludge pyrolysis technology.

[0045] In a specific embodiment, the oil-containing sludge pyrolysis residue contains 20-30 wt% of Fe2O3 and 30-40 wt% of Al2O3.

[0046] In a preferred embodiment, the oil-containing sludge pyrolysis residue contains 20-30 wt% of Fe2O3, 30-40 wt% of Al2O3, 20-30 wt% of SiO2, 10-20 wt% of CaO and 0-5 wt% of Na2O.

[0047] In a specific embodiment, the residual carbon of the oil-containing sludge pyrolysis residue burned at 500-600 °C is <1 wt%. The measurement method of the residual carbon is GB / T268.

[0048] In the method of the present invention, in order to obtain a heterogeneous catalyst with a layered double hydroxide structure, appropriate ratios of Zn, Al, and Fe, high catalytic activity, and high decomposition rate of phenols in wastewater, the dosage ratio of the zinc salt and the oil-containing sludge pyrolysis residue needs to be limited within a suitable range.

[0049] In a preferred embodiment, in step (1), the weight ratio of the zinc salt to the pyrolysis residue of the oily sludge is 0.5 - 5:1, preferably 1 - 2:1.

[0050] In a more preferred embodiment, the weight ratio of the zinc salt to the pyrolysis residue of the oily sludge is 1 - 1.5:1. Within this range, the prepared heterogeneous catalyst has higher catalytic activity and a higher decomposition rate of phenols in wastewater.

[0051] In the present invention, the type of the zinc salt is not limited and can be a conventional choice in the art. In a specific embodiment, the zinc salt can be at least one of zinc nitrate, sulfate, and zinc chloride, preferably zinc nitrate. In the present invention, the zinc salt can be an anhydrous zinc salt and / or a zinc salt crystal.

[0052] In the present invention, the function of ball milling is to cause physical and chemical transformation and structural changes during the aggregation of substances under the action of mechanical force.

[0053] In a specific embodiment, the ball milling is carried out in a conventional ball mill, such as a stainless - steel ball mill. Further, zirconia grinding balls can be placed in the ball mill as the ball - milling medium.

[0054] In the present invention, step (1) specifically includes: dry - milling the zinc salt and the pyrolysis residue of the oily sludge, and then wet - milling.

[0055] In a preferred embodiment, step (1) includes: mixing the zinc salt and the pyrolysis residue of the oily sludge evenly, sieving to obtain the sieved mixed material, and then dry - milling and wet - milling.

[0056] In a specific embodiment, the conditions for dry - milling include: the dry - milling rate (the rotation speed of the ball mill) is 200 - 600 rmp, and the dry - milling time is 4 - 6 h. In the present invention, if the dry - milling time is too short, the physical and chemical transformation and structural changes of the substances cannot occur sufficiently, and the catalytic activity of the obtained material under visible - light irradiation is low.

[0057] In a specific embodiment, the conditions for wet - milling include: the wet - milling rate (the rotation speed of the ball mill) is 200 - 600 rmp, and the wet - milling time is 1 - 2 h.

[0058] In the present invention, too much water cannot be added during the wet - milling process. In a specific embodiment, water is added at a ratio of 1 mL of water to 10 g of the sieved mixed material. If the amount of water added is too much, the catalytic activity of the obtained material under visible - light irradiation is low.

[0059] In a specific embodiment, the carbonization process in step (2) can directly carbonize the ball - milled mixture obtained in step (1).

[0060] In another specific embodiment, step (2) specifically includes: mixing the ball-milled mixture with the sodium carbonate solution and then performing carbonization.

[0061] In a preferred embodiment, the dosage ratio of the sodium carbonate solution to the pyrolysis residue of the oily sludge is 0.5 - 2 mL : 1 g.

[0062] In a more preferred embodiment, the concentration of the sodium carbonate solution is 0.1 - 0.2 mol / L.

[0063] In the present invention, the carbonization temperature is relatively low. The role of carbonization is the exchange of carbonate ions and hydroxide ions, that is, the product obtained in the ball-milling process reacts with Na2CO3. In this process, CO3 2- intercalation exchanges hydroxide ions with the ball-milled product.

[0064] In a specific embodiment, the temperature of the carbonization in step (2) can be 60 °C, 70 °C, 80 °C, 90 °C or 100 °C.

[0065] In a preferred embodiment, the temperature of the carbonization in step (2) is 790 - 90 °C.

[0066] In a specific embodiment, the time of the carbonization in step (2) is 1 - 2 h.

[0067] The second aspect of the present invention provides an oily sludge-based heterogeneous catalyst prepared by the method described above.

[0068] The present invention uses the residue of oily sludge as the main raw material and synthesizes a novel Fe2O3 / Zn-Al LDH composite material (F / ZA-LDH) with a crystalline hydrotalcite structure by a green and feasible mechanochemical synthesis method. There is a heterogeneous interface between Fe2O3 and Zn-Al LDH in the synthesized Fe2O3 / Zn-Al LDH composite material.

[0069] The third aspect of the present invention provides an application of the oily sludge-based heterogeneous catalyst described above as a heterogeneous Fenton catalyst.

[0070] The fourth aspect of the present invention provides a method for degrading organic substances in wastewater, which includes: reacting the oily sludge-based heterogeneous catalyst, peroxide and phenolic wastewater described above under visible light.

[0071] In the present invention, in order to promote the catalytic decomposition of peroxide and thus achieve the decomposition of phenols in wastewater, the dosages of the oily sludge-based heterogeneous catalyst and the peroxide need to be controlled within an appropriate range.

[0072] In the specific embodiment, the dosage ratio of the oil-containing sludge-based heterogeneous catalyst, the peroxide and the phenol in the phenol-containing wastewater is 1 g: 0.01-0.1 mmol: 0.005-0.05 mmol, that is, when the phenol content in the wastewater is 0.005-0.05 mmol, 1 g of the oil-containing sludge-based heterogeneous catalyst and 0.005-0.05 mmol of the peroxide need to be added.

[0073] In the specific operation of the present invention, the oil-containing sludge-based heterogeneous catalyst can be first added to the phenol-containing wastewater for adsorption for a period of time, and then the peroxide is added, and the degradation of phenols in the wastewater is completed through the generated free radicals; or the oil-containing sludge-based heterogeneous catalyst, the peroxide and the phenol-containing wastewater can be directly mixed for reaction.

[0074] In the specific embodiment, the reaction time of the mixture of the oil-containing sludge-based heterogeneous catalyst, the peroxide and the phenol-containing wastewater under visible light is 1-10 h.

[0075] In the present invention, the peroxide can be a conventional choice in the art as long as it can decompose to generate hydroxyl radicals and superoxide radicals to effectively decompose the phenolic organic matter in the wastewater.

[0076] In the specific embodiment, the peroxide is hydrogen peroxide and / or persulfate. In the preferred embodiment, the peroxide is persulfate; when the peroxide is persulfate, the decomposition rate of the phenolic organic matter in the wastewater by the oil-containing sludge-based heterogeneous catalyst is further improved. In the present invention, the persulfate is sodium persulfate and / or potassium persulfate.

[0077] In the preferred embodiment, the phenol-containing wastewater is phenol wastewater.

[0078] In the preferred embodiment, the phenol concentration in the phenol wastewater is 5-15 mmol / L.

[0079] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0080] In the following examples and comparative examples, the oil-containing sludge pyrolysis residue is from the pyrolysis resource utilization device of refinery oil-containing sludge, which contains 22.2 wt% of Fe2O3, 35.4 wt% of Al2O3, 24.3 wt% of SiO2, 13.5 wt% of CaO and 2.5 wt% of Na2O; the residual carbon of the oil-containing sludge pyrolysis residue burned at 600 °C is <1 wt%.

[0081] Example 1

[0082] 1) Mix Zn(NO3)2·6H2O and the pyrolysis residue of oily sludge evenly at a mass ratio of 1:1, and sieve through a 200-mesh sieve for standby;

[0083] 2) Put the sieved mixed material in step 1) into a ball mill tank equipped with zirconia grinding balls, and the ball-to-material ratio is 40:1;

[0084] 3) Set the ball mill speed to 400 rpm and the dry milling time to 5 h;

[0085] 4) Add water during wet milling (add according to the ratio of adding 1 mL of water to 10 g of the sieved mixed material), the ball mill speed is 400 rpm, and set the wet milling time to 2 h;

[0086] 5) Mix the ball mill mixture in step 4) with the sodium carbonate solution (the dosage ratio of the sodium carbonate solution to the pyrolysis residue of oily sludge is 1 mL:1 g, and the concentration of the sodium carbonate solution is 0.15 mol / L), and then carry out carbonization at 80 °C for 1.5 h to obtain an oily sludge-based heterogeneous catalyst;

[0087] 6) Add the oily sludge-based heterogeneous catalyst to the phenol-containing wastewater, the catalyst dosage is 1 g / L, the concentration of sodium persulfate is 20 mmol / L, and the phenol concentration in the phenol-containing wastewater is 10 mmol / L, and place it under simulated sunlight;

[0088] 7) After reacting for 5 h, filter the reacted wastewater with a 0.22 μm filter membrane, and use liquid chromatography to measure the concentration of phenol in the reacted wastewater, and calculate the degradation rate of phenol.

[0089] The calculation method of the degradation rate of phenol is: (the phenol concentration in the phenol-containing wastewater in step 5) - the phenol concentration in the reacted wastewater measured in step 6)) / the phenol concentration in the phenol-containing wastewater in step 5) × 100%.

[0090] After calculation, the degradation rate (decomposition rate) of phenol in the wastewater is 90.20%. It can be seen that the oily sludge-based heterogeneous catalyst prepared in this example exhibits high catalytic activity under visible light irradiation, and can effectively degrade the wastewater after 5 h of illumination.

[0091] Example 2

[0092] 1) Mix Zn(NO3)2·6H2O and the pyrolysis residue of oily sludge evenly at a mass ratio of 1:1, and sieve through a 200-mesh sieve for standby;

[0093] 2) Put the sieved mixed material in step 1) into a ball mill tank equipped with zirconia grinding balls, and the ball-to-material ratio is 40:1;

[0094] 3) Set the ball mill speed to 200 rpm and the dry milling time to 5 h;

[0095] 4) Add water during the wet milling process (add in a ratio of 1 mL of water per 10 g of the sieved mixed material), the ball milling speed is 200 rpm, and set the wet milling time to 2 h;

[0096] 5) Mix the ball-milled mixture in step 4) with the sodium carbonate solution (the dosage ratio of the sodium carbonate solution to the pyrolysis residue of oily sludge is 1 mL:1 g, and the concentration of the sodium carbonate solution is 0.15 mol / L), and then carry out carbonization at 80 °C for 1.5 h to obtain an oily sludge-based heterogeneous catalyst;

[0097] 6) Add the oily sludge-based heterogeneous catalyst to the phenol-containing wastewater, the catalyst dosage is 1 g / L, the concentration of sodium persulfate is 20 mmol / L, and the phenol concentration in the phenol-containing wastewater is 10 mmol / L, and place it under simulated sunlight;

[0098] 7) After reacting for 5 h, filter the reacted wastewater through a 0.22 μm filter membrane, and use liquid chromatography to measure the concentration of phenol in the reacted wastewater, and calculate the degradation rate of phenol.

[0099] The calculation method of the degradation rate of phenol is: (the phenol concentration in the phenol-containing wastewater in step 5) - the phenol concentration in the reacted wastewater measured in step 6)) / the phenol concentration in the phenol-containing wastewater in step 5) × 100%.

[0100] After calculation, the degradation rate (decomposition rate) of phenol in the wastewater is 81.3%. It can be seen that the oily sludge-based heterogeneous catalyst prepared in this example exhibits high catalytic activity under visible light irradiation, and after 5 h of light irradiation, effective degradation of the wastewater can be achieved.

[0101] Compared with Example 1, the ball milling speed in Example 2 is smaller, resulting in insufficient chemical reactions and crystal structure changes of substances, thus leading to a decrease in the catalytic activity of the finally prepared composite material.

[0102] Example 3

[0103] 1) Mix Zn(NO3)2·6H2O and the pyrolysis residue of oily sludge evenly at a mass ratio of 2:1, and sieve through a 200-mesh sieve for standby;

[0104] 2) Put the sieved mixed material in step 1) into a ball milling tank equipped with zirconia grinding balls, and the ball-to-material ratio is 40:1;

[0105] 3) Set the ball milling speed to 600 rpm and the dry milling time to 5 h;

[0106] 4) Add water during the wet milling process (add in a ratio of 1 mL of water per 10 g of the sieved mixed material), the ball milling speed is 600 rpm, and set the wet milling time to 2 h;

[0107] 5) Mix the ball-milled mixture in step 4) with the sodium carbonate solution (the dosage ratio of the sodium carbonate solution to the pyrolysis residue of oily sludge is 1 mL:1 g, and the concentration of the sodium carbonate solution is 0.15 mol / L), and then carry out carbonization at 80 °C for 1.5 h to obtain the oily sludge-based heterogeneous catalyst;

[0108] 6) Add the oily sludge-based heterogeneous catalyst to the phenol-containing wastewater, with the catalyst dosage of 1 g / L, the concentration of sodium persulfate of 20 mmol / L, and the phenol concentration in the phenol-containing wastewater of 10 mmol / L, and place it under simulated sunlight;

[0109] 7) After reacting for 5 h, filter the reacted wastewater with a 0.22 μm filter membrane, and use liquid chromatography to determine the concentration of phenol in the reacted wastewater, and calculate the degradation rate of phenol.

[0110] The calculation method of the degradation rate of phenol is: (the phenol concentration in the phenol-containing wastewater in step 5) - the phenol concentration in the reacted wastewater measured in step 6)) / the phenol concentration in the phenol-containing wastewater in step 5) × 100%.

[0111] After calculation, the degradation rate (decomposition rate) of phenol in the wastewater is 82.1%. It can be seen that the oily sludge-based heterogeneous catalyst prepared in this example exhibits high catalytic activity under visible light irradiation, and can effectively degrade the wastewater after 5 h of illumination.

[0112] Example 4

[0113] 1) Mix Zn(NO3)2·6H2O and the pyrolysis residue of oily sludge evenly at a mass ratio of 2:1, and sieve through a 200-mesh sieve for standby;

[0114] 2) Put the sieved mixed material in step 1) into a ball mill tank equipped with zirconia grinding balls, and the ball-to-material ratio is 20:1;

[0115] 3) Set the ball mill rotation speed to 400 rpm and the dry milling time to 5 h;

[0116] 4) Add water during the wet milling process (add according to the ratio of 1 mL of water to 10 g of the sieved mixed material), the ball mill rotation speed is 200 rpm, and set the wet milling time to 2 h;

[0117] 5) Mix the ball-milled mixture in step 4) with the sodium carbonate solution (the dosage ratio of the sodium carbonate solution to the pyrolysis residue of oily sludge is 1 mL:1 g, and the concentration of the sodium carbonate solution is 0.15 mol / L), and then carry out carbonization at 80 °C for 1.5 h to obtain the oily sludge-based heterogeneous catalyst;

[0118] 6) Add the oil sludge-based heterogeneous catalyst to the phenol-containing wastewater. The catalyst dosage is 1 g / L, the concentration of sodium persulfate is 20 mmol / L, and the phenol concentration in the phenol-containing wastewater is 10 mmol / L. Place it under simulated sunlight.

[0119] 7) After reacting for 5 h, filter the reacted wastewater through a 0.22 μm filter membrane, and use liquid chromatography to measure the phenol concentration in the reacted wastewater, and calculate the degradation rate of phenol.

[0120] The calculation method of the phenol degradation rate is: (the phenol concentration in the phenol-containing wastewater in step 5 - the phenol concentration in the reacted wastewater measured in step 6) / the phenol concentration in the phenol-containing wastewater in step 5 × 100%.

[0121] After calculation, the degradation rate (decomposition rate) of phenol in the wastewater is 71.4%. It can be seen that the oil sludge-based heterogeneous catalyst prepared in this example exhibits high catalytic activity under visible light irradiation and can effectively degrade the wastewater after 5 h of illumination.

[0122] Compared with Example 2, the increase in zinc content in Example 4 will result in an obvious zinc nitrate hydrate peak in the prepared composite material; the newly formed zinc nitrate hydrate will cover the active components, ultimately leading to a decrease in the catalytic activity of the composite material; and too low zinc content will result in less formation of F / ZA-LDH and a reduction in active components.

[0123] Example 5

[0124] 1) Mix Zn(NO3)2·6H2O and the oil sludge pyrolysis residue evenly at a mass ratio of 3:1, and sieve through a 200-mesh sieve for later use.

[0125] 2) Put the sieved mixed material in step 1) into a ball mill tank equipped with zirconia grinding balls, and the ball-to-material ratio is 40:1.

[0126] 3) Set the ball mill rotation speed to 400 rpm and dry mill for 5 h.

[0127] 4) Add water during the wet milling process (add according to the ratio of 1 mL of water to 10 g of the sieved mixed material), the ball mill rotation speed is 400 rpm, and set the wet milling time to 2 h.

[0128] 5) Mix the ball mill mixture in step 4) with the sodium carbonate solution (the dosage ratio of the sodium carbonate solution to the oil sludge pyrolysis residue is 1 mL:1 g, and the concentration of the sodium carbonate solution is 0.15 mol / L), and then carry out carbonization at 80 °C for 1.5 h to obtain the oil sludge-based heterogeneous catalyst.

[0129] 6) Add the oil sludge-based heterogeneous catalyst to the phenol-containing wastewater. The catalyst dosage is 1 g / L, the concentration of sodium persulfate is 20 mmol / L, and the phenol concentration in the phenol-containing wastewater is 10 mmol / L. Place it under simulated sunlight.

[0130] 7) After reacting for 5 h, filter the reacted wastewater through a 0.22-μm filter membrane, and use liquid chromatography to measure the phenol concentration in the reacted wastewater, and calculate the degradation rate of phenol.

[0131] The calculation method of the degradation rate of phenol is: (the phenol concentration in the phenol-containing wastewater in step 5 - the phenol concentration in the reacted wastewater measured in step 6) / the phenol concentration in the phenol-containing wastewater in step 5 × 100%.

[0132] After calculation, the degradation rate (decomposition rate) of phenol in the wastewater is 68.20%. It can be seen that the oil sludge-based heterogeneous catalyst prepared in this example exhibits high catalytic activity under visible light irradiation, and can effectively degrade the wastewater after 5 h of illumination.

[0133] Example 6

[0134] Implement according to the method of Example 1, except that the carbonization temperature is 100 °C. The specific operation includes the following steps:

[0135] 1) Mix Zn(NO3)2·6H2O and the oil sludge pyrolysis residue evenly at a mass ratio of 1:1, and sieve through a 200-mesh sieve for later use;

[0136] 2) Put the sieved mixed material in step 1) into a ball mill tank equipped with zirconia grinding balls, and the ball-to-material ratio is 40:1;

[0137] 3) Set the ball mill rotation speed to 400 rpm and the dry milling time to 5 h;

[0138] 4) Add water during the wet milling process (add according to the ratio of 1 mL of water to 10 g of the sieved mixed material), the ball mill rotation speed is 400 rpm, and set the wet milling time to 2 h;

[0139] 5) Mix the ball mill mixture in step 4) with the sodium carbonate solution (the dosage ratio of the sodium carbonate solution to the oil sludge pyrolysis residue is 1 mL:1 g, and the concentration of the sodium carbonate solution is 0.15 mol / L), and then carry out carbonization at 100 °C for 1.5 h to obtain the oil sludge-based heterogeneous catalyst;

[0140] 6) Add the oil sludge-based heterogeneous catalyst to the phenol-containing wastewater. The catalyst dosage is 1 g / L, the concentration of sodium persulfate is 20 mmol / L, and the phenol concentration in the phenol-containing wastewater is 10 mmol / L. Place it under simulated sunlight.

[0141] 7) After reacting for 5 h, the reacted wastewater was filtered through a 0.22-μm filter membrane, and the concentration of phenol in the reacted wastewater was determined by liquid chromatography to calculate the degradation rate of phenol.

[0142] The calculation method of the degradation rate of phenol is: (concentration of phenol in the phenol-containing wastewater in step 5 - concentration of phenol in the reacted wastewater measured in step 6) / concentration of phenol in the phenol-containing wastewater in step 5 × 100%.

[0143] After calculation, the degradation rate (decomposition rate) of phenol in the wastewater was 83.9%. It can be seen that the oil sludge-based heterogeneous catalyst prepared in this example exhibited high catalytic activity under visible light irradiation and could achieve effective degradation of the wastewater after 5 h of illumination.

[0144] Example 7

[0145] It was carried out according to the method of Example 1, except that the carbonization temperature was 60 °C. The specific operation included the following steps:

[0146] 1) Zn(NO3)2·6H2O and the pyrolysis residue of oil sludge were mixed evenly at a mass ratio of 1:1 and passed through a 200-mesh sieve for standby;

[0147] 2) The sieved mixed material in step 1) was put into a ball mill tank equipped with zirconia grinding balls, and the ball-to-material ratio was 40:1;

[0148] 3) The ball mill rotation speed was set at 400 rpm, and the dry milling time was 5 h;

[0149] 4) During wet milling, water was added (added according to the ratio of 1 mL of water to 10 g of the sieved mixed material), the ball mill rotation speed was 400 rpm, and the wet milling time was set at 2 h;

[0150] 5) The ball mill mixture in step 4) was mixed with the sodium carbonate solution (the dosage ratio of the sodium carbonate solution to the pyrolysis residue of oil sludge was 1 mL:1 g, and the concentration of the sodium carbonate solution was 0.15 mol / L), and then carbonized at 60 °C for 1.5 h to obtain an oil sludge-based heterogeneous catalyst;

[0151] 6) The oil sludge-based heterogeneous catalyst was added to the phenol-containing wastewater, the catalyst dosage was 1 g / L, the concentration of potassium persulfate was 20 mmol / L, and the concentration of phenol in the phenol-containing wastewater was 10 mmol / L, and it was placed under simulated sunlight;

[0152] 7) After reacting for 5 h, the reacted wastewater was filtered through a 0.22-μm filter membrane, and the concentration of phenol in the reacted wastewater was determined by liquid chromatography to calculate the degradation rate of phenol.

[0153] The calculation method of the degradation rate of phenol is: (concentration of phenol in the phenol-containing wastewater in step 5 - concentration of phenol in the wastewater after the reaction measured in step 6) / concentration of phenol in the phenol-containing wastewater in step 5 × 100%.

[0154] After calculation, the degradation rate (decomposition rate) of phenol in the wastewater is 70.74%. It can be seen that the oil sludge-based heterogeneous catalyst prepared in this example exhibits high catalytic activity under visible light irradiation and can effectively degrade the wastewater after 5 hours of light irradiation.

[0155] Comparative Example 1

[0156] It was carried out according to the method of Example 1, except that Zn(NO3)2·6H2O was not added in step 1). The specific operations include the following steps:

[0157] 1) Sieving the oil sludge pyrolysis residue through a 200-mesh sieve for standby;

[0158] 2) Putting the sieved mixture in step 1) into a ball mill tank equipped with zirconia grinding balls, with a ball-to-material ratio of 40:1;

[0159] 3) Setting the ball mill rotation speed to 400 rpm and the dry milling time to 5 hours;

[0160] 4) Adding 1 mL of water during the wet milling process, setting the ball mill rotation speed to 400 rpm, and setting the wet milling time to 2 hours;

[0161] 5) Mixing the ball mill mixture in step 4) with the sodium carbonate solution (the dosage ratio of the sodium carbonate solution to the oil sludge pyrolysis residue is 1 mL:1 g, and the concentration of the sodium carbonate solution is 0.15 mol / L), and then carrying out carbonization at 80 °C for 1.5 hours to obtain an oil sludge-based heterogeneous catalyst;

[0162] 6) Adding the oil sludge-based heterogeneous catalyst to the phenol-containing wastewater, with a catalyst dosage of 1 g / L, a sodium persulfate concentration of 20 mmol / L, and a phenol concentration of 10 mmol / L in the phenol-containing wastewater, and placing it under simulated sunlight;

[0163] 7) After reacting for 5 hours, filtering the reacted wastewater with a 0.22 μm filter membrane, measuring the concentration of phenol in the wastewater after the reaction by liquid chromatography, and calculating the degradation rate of phenol.

[0164] The calculation method of the degradation rate of phenol is: (concentration of phenol in the phenol-containing wastewater in step 5 - concentration of phenol in the wastewater after the reaction measured in step 6) / concentration of phenol in the phenol-containing wastewater in step 5 × 100%.

[0165] After calculation, the degradation rate (decomposition rate) of phenol in the wastewater is 20.3%. It can be seen that mainly due to the insufficient Zn(NO3)2·6H2O, less F / ZA-LDH is formed, resulting in a serious decline in catalytic activity.

[0166] Comparative Example 2

[0167] Implemented according to the method of Example 1, except that Cu(NO3)2·3H2O is used instead of Zn(NO3)2·6H2O in step 1). The specific operations include the following steps:

[0168] 1) Mix Cu(NO3)2·3H2O and the pyrolysis residue of oily sludge evenly at a mass ratio of 1:1, and sieve through a 200-mesh sieve for later use;

[0169] 2) Put the sieved mixture from step 1) into a ball mill tank equipped with zirconia grinding balls, and the ball-to-material ratio is 40:1;

[0170] 3) Set the ball mill rotation speed to 400 rpm and the dry milling time to 5 h;

[0171] 4) Add 1 mL of water during the wet milling process, the ball mill rotation speed is 400 rpm, and set the wet milling time to 2 h;

[0172] 5) Mix the ball mill mixture from step 4) with the sodium carbonate solution (the dosage ratio of the sodium carbonate solution to the pyrolysis residue of oily sludge is 1 mL:1 g, and the concentration of the sodium carbonate solution is 0.15 mol / L), and then carry out carbonization at 80°C for 1.5 h to obtain an oily sludge-based heterogeneous catalyst;

[0173] 6) Add the oily sludge-based heterogeneous catalyst to the phenol-containing wastewater, the catalyst dosage is 1 g / L, the concentration of sodium persulfate is 20 mmol / L, and the phenol concentration in the phenol-containing wastewater is 10 mmol / L, and place it under simulated sunlight;

[0174] 7) After reacting for 5 h, filter the reacted wastewater through a 0.22-μm filter membrane, and use liquid chromatography to measure the concentration of phenol in the reacted wastewater, and calculate the degradation rate of phenol.

[0175] The calculation method of the degradation rate of phenol is: (the concentration of phenol in the phenol-containing wastewater in step 5) - the concentration of phenol in the reacted wastewater measured in step 6)) / the concentration of phenol in the phenol-containing wastewater in step 5) × 100%.

[0176] After calculation, the degradation rate (decomposition rate) of phenol in the wastewater is 15.3%. It can be seen that in this example, only when the pyrolysis residue of oily sludge and zinc salt are used as raw materials, the oily sludge-based heterogeneous catalyst prepared shows high catalytic activity under visible light irradiation, and after 5 h of irradiation, effective degradation of wastewater can be achieved.

[0177] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for an oil-containing sludge-based heterogeneous catalyst, characterized in that, The method includes the following steps: (1) Ball-mill a zinc salt and the pyrolysis residue of oily sludge to obtain a ball-milled mixture; (2) Carbonize the ball-milled mixture at 60 - 100 °C to obtain a heterogeneous catalyst based on oily sludge; Among them, the pyrolysis residue of oily sludge contains 20 - 30 wt% of Fe2O3 and 30 - 40 wt% of Al2O3.

2. The method according to claim 1, characterized in that, In step (1), the weight ratio of the dosage of the zinc salt to the pyrolysis residue of oily sludge is 0.5 - 5:1, preferably 1 - 2:

1.

3. The method according to claim 1 or 2, characterized in that The residual carbon of the pyrolysis residue of oily sludge burned at 500 - 600 °C is < 1 wt%.

4. The method according to any one of claims 1 to 3, characterized in that Step (1) specifically includes: dry-mill the zinc salt and the pyrolysis residue of oily sludge, and then wet-mill them; Preferably, the conditions for dry-milling include: the dry-milling rate is 200 - 600 rmp, and the dry-milling time is 4 - 6 h; Preferably, the conditions for wet-milling include: the wet-milling rate is 200 - 600 rmp, and the wet-milling time is 1 - 2 h.

5. The method according to any one of claims 1-4, characterized in that Step (2) specifically includes: mix the ball-milled mixture with the sodium carbonate solution and then carbonize it; Preferably, the dosage ratio of the sodium carbonate solution to the pyrolysis residue of oily sludge is 0.5 - 2 mL:1 g; Preferably, the concentration of the sodium carbonate solution is 0.1 - 0.2 mol / L.

6. The method according to any one of claims 1 to 5, characterized in that In step (2), the carbonization time is 1 - 2 h.

7. A heterogeneous catalyst based on oily sludge prepared by the method according to any one of claims 1 - 6.

8. Application of the heterogeneous catalyst based on oily sludge according to claim 7 as a heterogeneous Fenton catalyst.

9. A method for degrading organic matter in wastewater, characterized in that, This method includes: reacting the heterogeneous catalyst based on oily sludge according to claim 7, a peroxide, and phenolic wastewater under visible light.

10. The method according to claim 9, wherein The dosage ratio of the heterogeneous catalyst based on oily sludge, the peroxide, and phenol in the phenolic wastewater is 1 g:0.01 - 0.1 mmol:0.005 - 0.05 mmol.

11. The method according to claim 9 or 10, characterized in that, The peroxide is hydrogen peroxide and / or persulfate.

12. The method according to any one of claims 9-11, characterized in that, The phenolic wastewater is phenol wastewater; Preferably, the phenol concentration in the phenol wastewater is 5 - 15 mmol / L.

13. The method according to any one of claims 9-12, characterized in that The reaction time is 1 - 10 h.

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