Preparation method of ozone oxidation catalyst and wastewater treatment method

Abstract

The invention belongs to the technical field of wastewater treatment, and particularly relates to a preparation method of an ozone oxidation catalyst, the catalyst and a use method thereof, and a wastewater treatment method using a wastewater treatment device. The preparation method of the ozone oxidation catalyst comprises the following steps: performing primary pyrolysis on dried oil sludge in an inert atmosphere to obtain first carbon powder; mixing the first carbon powder with an activator, and activating to obtain a first transition product; performing second pyrolysis on the first transition product in an inert atmosphere to obtain second carbon powder; mixing the second carbon powder with urea to obtain a second transition product; and carrying out third pyrolysis on the second transition product in an inert atmosphere to obtain the ozone oxidation catalyst. The ozone oxidation catalyst prepared according to the invention has stronger adsorption capacity on ozone and organic matters, so that wastewater treatment can be realized more efficiently.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and in particular relates to a method for preparing an ozone oxidation catalyst, a catalyst and a method for using the catalyst, and a method for treating wastewater using a wastewater treatment device. Background Art

[0002] Ozone catalytic oxidation technology is a commonly used treatment technology for removing organic matter from wastewater. The key point of ozone catalytic oxidation technology is to make the ozone dissolved in water be adsorbed by the catalyst, and under the action of the catalyst, hydroxyl radicals with strong oxidizing ability are generated. At the same time, the catalyst adsorbs the organic matter in the wastewater, and the generated hydroxyl radicals react with the organic matter adsorbed by the catalyst, thereby achieving the purpose of treating the wastewater. Therefore, the adsorption capacity of this type of catalyst for ozone, organic matter, etc. is the key to determining whether ozone catalytic oxidation can be carried out smoothly and efficiently. However, the adsorption capacity of this type of catalyst provided in the prior art is gradually unable to meet the relevant requirements in the field of wastewater treatment which is in constant development. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a method for preparing an ozone oxidation catalyst, a catalyst and a method for using the catalyst, and a method for treating wastewater using a wastewater treatment device.

[0004] According to a first aspect of the present invention, a method for preparing an ozone oxidation catalyst is provided.

[0005] The preparation method of the ozone oxidation catalyst comprises the following steps:

[0006] (1) performing a first pyrolysis on the dried oil sludge in an inert atmosphere to obtain a first carbon powder;

[0007] (2) mixing the first carbon powder with an activator and activating the mixture to obtain a first transition product;

[0008] (3) subjecting the first transition product to a second pyrolysis in an inert atmosphere to obtain a second carbon powder;

[0009] (4) mixing the second carbon powder with urea to obtain a second transition product;

[0010] (5) The second transition product is subjected to a third pyrolysis in an inert atmosphere to obtain an ozone oxidation catalyst.

[0011] As an extension of the above technical solution, the present invention also provides the following embodiments:

[0012] In the step (1), the dried sludge is subjected to a first pyrolysis in an inert atmosphere to obtain a third transition product, and the third transition product is washed with a dilute acid to obtain a first carbon powder.

[0013] In the step (2), the mass ratio of the second carbon powder to the activator is 1:3 to 3:1.

[0014] In the step (4), the mass ratio of the second carbon powder to urea is 1:0.2-0.6.

[0015] In the step (5), the heating rate of the second transition product during the third pyrolysis in an inert atmosphere is controlled at 5-10°C / min.

[0016] After step (5), the method includes step (6) of performing hydrophilic treatment on the ozone oxidation catalyst, wherein step (6) includes:

[0017] 1) After mixing the ozone oxidation catalyst and a first binder, adding an appropriate amount of water to obtain a first paste, wherein the first binder is a water-soluble organic matter;

[0018] 2) Using the first paste as a raw material to perform granulation operation to obtain first particles, and drying the first particles to obtain an ozone oxidation catalyst with a hydrophilic function.

[0019] After step (5), the method includes a step (7) of performing a hydrophobic treatment on the ozone oxidation catalyst, wherein the step (7) includes:

[0020] 3) After mixing the ozone oxidation catalyst and the second binder, adding an appropriate amount of water to obtain a second paste, wherein the second binder is a hydrophobic organic substance;

[0021] 4) Using the second paste as a raw material, a granulation operation is performed to obtain second particles, and the second particles are heat-treated to obtain an ozone oxidation catalyst having a hydrophobic function.

[0022] The first binder is sodium carboxymethyl cellulose and / or sodium alginate.

[0023] The second binder is a polytetrafluoroethylene solution.

[0024] The heat treatment in step 4) includes two stages, the treatment temperature range of the first stage is 300-400°C, and the treatment temperature range of the second stage is 100-120°C.

[0025] The pyrolysis temperature ranges of the first pyrolysis, the second pyrolysis and the third pyrolysis are all 500-700°C.

[0026] The dilute acid includes dilute hydrochloric acid or dilute acetic acid.

[0027] The activator includes one or a mixture of two or more of KOH, Na2CO3, FeCl3, ZnCl2 and K2CO3.

[0028] According to a second aspect of the present invention, a catalyst is provided.

[0029] The catalyst is prepared by the above-mentioned preparation method of the ozone oxidation catalyst.

[0030] According to a third aspect of the present invention, a method for using a catalyst is provided.

[0031] The method for using the catalyst comprises the following steps:

[0032] The catalysts as described above are used in a layered stack arrangement.

[0033] As an extension of the above technical solution, the present invention also provides the following embodiments:

[0034] Several layers of catalysts with hydrophilic function are stacked on or below several layers of catalysts with hydrophobic function for use.

[0035] Catalysts with hydrophilic function and catalysts with hydrophobic function are arranged in layers and stacked for use.

[0036] The catalyst having a hydrophilic function has a different outer diameter from the catalyst having a hydrophobic function.

[0037] According to a fourth aspect of the present invention, a wastewater treatment method using a wastewater treatment device is provided.

[0038] The wastewater treatment device in the wastewater treatment method using the wastewater treatment device comprises:

[0039] A tower body and a processing unit arranged in the tower body, a water inlet is arranged at the upper part of the tower body, a water outlet is arranged at the lower part of the tower body, and the processing unit is located between the water inlet and the water outlet, wherein the processing unit includes: a floating valve tower plate, an air intake assembly and a catalytic tower plate loaded with the catalyst as described above, the floating valve tower plate is located above the air intake assembly, and the catalytic tower plate is located below the air intake assembly.

[0040] As an extension of the above technical solution, the present invention also provides the following embodiments:

[0041] The catalytic tower plate includes a support plate, on which the catalyst is loaded, and the catalyst is used according to the method for using the catalyst as described above.

[0042] The catalytic tower plate comprises a first baffle, one side of which is connected to the support plate, and the value range of the angle α between the baffle and the support plate is: 0°<α≤90°.

[0043] The advantages of the present invention compared to the prior art are:

[0044] 1. The ozone oxidation catalyst prepared according to the technical solution of the present invention has abundant micropores and a larger specific surface area, and contains more pyridine-N, thereby having more active sites, thereby making the ozone oxidation catalyst have a stronger adsorption capacity for ozone and organic matter in wastewater, and ultimately enhancing the efficiency of ozone catalytic oxidation in the wastewater treatment process, especially having a more prominent catalytic oxidation effect on COD in gas field produced water;

[0045] 2. According to the technical solution of the present invention, on the basis of the prepared ozone oxidation catalyst with stronger adsorption capacity, a hydrophilic and hydrophobic ozone oxidation catalyst can be prepared, so that it can fully absorb the ozone dissolved in the wastewater and adsorb the ozone not dissolved in the wastewater, so that the ozone can be fully utilized to oxidize the organic matter in the wastewater, thereby improving the utilization rate of ozone;

[0046] 3. According to the method for using the catalyst of the present invention, by stacking the catalyst in layers in a certain manner, it is helpful to give full play to the catalytic oxidation ability of the catalyst on ozone, thereby improving the wastewater treatment capacity;

[0047] 4. The wastewater treatment method using the wastewater treatment device of the present invention utilizes the ozone oxidation catalyst prepared according to the technical solution of the present invention, thereby having a higher ozone utilization rate and a high-efficiency ozone catalytic oxidation level. In addition, the wastewater treatment method can enhance the mass transfer effect during the treatment process and improve the wastewater treatment efficiency;

[0048] 5. According to the technical solution of the present invention, waste sludge is used to prepare ozone oxidation catalyst, thereby realizing the recycling of waste, reducing the cost of wastewater treatment, and having better economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A flowchart of an embodiment of a method for preparing an ozone oxidation catalyst according to the present invention;

[0050] Figure 2 A schematic diagram of an arrangement of a catalyst in one embodiment of a method for using a catalyst according to the present invention;

[0051] Figure 3A schematic diagram of an arrangement of a catalyst in another embodiment of a method for using a catalyst according to the present invention;

[0052] Figure 4 A schematic diagram of an arrangement of a catalyst in another embodiment of a method for using a catalyst according to the present invention;

[0053] Figure 5 A schematic structural diagram of an embodiment of a wastewater treatment device according to the present invention;

[0054] Figure 6 is a schematic structural diagram of an embodiment of an air intake assembly according to the invention;

[0055] Figure 7 A schematic diagram of a top view of a floating valve tray according to an embodiment of the present invention;

[0056] Figure 8 A schematic structural diagram of another embodiment of a wastewater treatment device according to the present invention;

[0057] Fig. 9 A cross-sectional view of an embodiment of a catalytic tray of a wastewater treatment device according to the present invention;

[0058] In the present application, all drawings are schematic drawings, which are only used to illustrate the structure and principle of the present application, and are not necessarily drawn according to actual sizes and proportions.

[0059] The specific meanings of the reference numerals in the figures are as follows:

[0060] 1. Tower body; 11. Water inlet; 12. Water outlet; 13. Liquid inlet baffle; 14. Air inlet; 15. Inspection port; 16. Ozone collection port; 2. Processing unit; 21. Floating valve tower plate; 211. Floating valve overflow weir; 212. Floating valve downcomer plate; 213. Baffle bar; 214. Valve body; 215. First channel port; 22. Air inlet assembly; 221. Air distribution pipe; 222. Flange; 223. Air hole; 23. Catalyst Chemical tower plate; 231, support plate; 2311, woven mesh; 2312, cushion layer; 232, catalyst; 2321, catalyst with hydrophilic function; 2322, catalyst with hydrophobic function; 233, catalytic overflow weir; 234, catalytic downcomer plate; 235, second channel opening; 25, frame support beam; 26, support rod; 271, first baffle; 272, second baffle; 100, wastewater treatment device. DETAILED DESCRIPTION

[0061] The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0062] According to a first aspect of the present invention, a method for preparing an ozone oxidation catalyst is provided.

[0063] The preparation method of the ozone oxidation catalyst comprises the following steps:

[0064] (1) performing a first pyrolysis on the dried oil sludge in an inert atmosphere to obtain a first carbon powder;

[0065] (2) mixing the first carbon powder with an activator and activating the mixture to obtain a first transition product;

[0066] (3) subjecting the first transition product to a second pyrolysis in an inert atmosphere to obtain a second carbon powder;

[0067] (4) mixing the second carbon powder with urea to obtain a second transition product;

[0068] (5) The second transition product is subjected to a third pyrolysis in an inert atmosphere to obtain an ozone oxidation catalyst.

[0069] According to the preparation method of the ozone oxidation catalyst of the present invention, through the above-mentioned operation steps, the prepared ozone oxidation catalyst has more microporous structures and more pyridine-N that can provide active sites for ozone catalytic oxidation. Finally, the prepared ozone oxidation catalyst has a stronger adsorption capacity for ozone and organic matter in wastewater, thereby enhancing the efficiency of ozone catalytic oxidation in the wastewater treatment process. In addition, compared with the preparation method of directly activating the sludge and then pyrolyzing it, the yield of the preparation method according to the present invention can be increased by more than 5%, so that the technical solution provided by the present invention has higher economic efficiency.

[0070] Heavy metals in oil sludge generally exist in three forms: gas, fly ash, and residue. Its existence form depends on the volatility of heavy metals and their compounds, and volatility is closely related to melting and boiling points. In the present invention, the metal compounds in oil sludge are generally chloride and sulfate compounds. Metals or metal compounds with low melting and boiling points are easy to separate from the solid phase and mainly exist in the form of fly ash; metals or compounds with high melting and boiling points are generally retained in the carbon skeleton structure formed after the pyrolysis is completed, and then become components of the ozone oxidation catalyst after the preparation process is completed.

[0071] In a preferred embodiment of the present invention, the pyrolysis temperature range of the first pyrolysis, the second pyrolysis and the third pyrolysis is 500-700° C. By controlling the pyrolysis temperature within this range, certain substances that are originally present in the sludge and have an effect on ozone catalytic oxidation, such as sulfate compounds of metals such as cadmium, lead, chromium, copper, magnesium, and aluminum, and metal substances such as iron, manganese, copper, chromium, magnesium, and aluminum, can be retained, and substances that affect the formation of pore structures can be prevented from entering the carbon skeleton, thereby helping to improve the adsorption and catalytic oxidation capabilities of the prepared ozone oxidation catalyst.

[0072] In a preferred embodiment of the present invention, the pyrolysis temperature of the first pyrolysis, the second pyrolysis and the third pyrolysis is selected to be 600°C.

[0073] In one embodiment of the present invention, in step (1), the dried sludge is subjected to a first pyrolysis in an inert atmosphere to obtain a third transition product, and the third transition product is washed with dilute acid to obtain a first carbon powder. The ash originally present in the carbon skeleton of the third transition product can be removed by washing with dilute acid, leaving a large number of pores, so that the obtained first carbon powder has more micropores, thereby helping to improve the reaction efficiency of ozone catalytic oxidation.

[0074] In a preferred embodiment of the present invention, the dilute acid includes dilute hydrochloric acid or dilute acetic acid.

[0075] In a preferred embodiment of the present invention, the concentration of the dilute acid is 1-5 mol / L.

[0076] In a preferred embodiment of the present invention, the dilute acid is dilute hydrochloric acid, and the concentration is 3 mol / L.

[0077] In one embodiment of the present invention, in step (2), the mass ratio of the first carbon powder to the activator is 1:3 to 3:1.

[0078] In a preferred embodiment of the present invention, in step (2), the mass ratio of the first carbon powder to the activator is 1:3.

[0079] In one embodiment of the present invention, the activator in step (2) includes one or a mixture of two or more of KOH, Na2CO3, FeCl3, ZnCl2 and K2CO3. The use of the activator can make the prepared ozone oxidation catalyst have more abundant micropores and more pores, thereby helping to improve its adsorption capacity and catalytic oxidation capacity for ozone.

[0080] Preferably, the activating agent in step (2) is KOH.

[0081] In one embodiment of the present invention, in step (4), the mass ratio of the second carbon powder to urea is 1:0.2-0.6.

[0082] Preferably, the mass ratio of the second carbon powder to urea is 1:0.5.

[0083] By pyrolyzing the second transition product formed by mixing the second carbon powder and urea under certain temperature conditions, nitrogen is doped into the second carbon powder under the action of relevant components in the second carbon powder, so that the final ozone oxidation catalyst has more pyridine-N, which can provide more active sites for ozone catalytic oxidation. The ozone oxidation catalyst finally prepared has a strong catalytic oxidation effect on the difficult-to-degrade organic matter in the wastewater under the synergistic effect of metal elements such as iron and manganese and more pyridine-N.

[0084] In one embodiment of the present invention, in step (5), the heating rate of the third pyrolysis of the second transition product is controlled at 5-10°C / min. At this heating rate, the reaction is relatively complete, and the final product is mainly solid phase, and the yield of the ozone oxidation catalyst is higher.

[0085] In one embodiment of the present invention, in step (5), during the third pyrolysis of the second transition product, after the pyrolysis temperature rises to the set temperature, the temperature is maintained for a certain period of time to allow the reaction to proceed more thoroughly, thereby helping to further improve the final yield of the ozone oxidation catalyst.

[0086] In one embodiment of the present invention, after step (5), a step (6) of hydrophilizing the ozone oxidation catalyst is included, and step (6) includes:

[0087] 1) After mixing the ozone oxidation catalyst and the first binder, adding an appropriate amount of water to obtain a first paste, wherein the first binder is a water-soluble organic matter;

[0088] 2) Using the first paste as a raw material to perform granulation operation to obtain first particles, and drying the first particles to obtain an ozone oxidation catalyst having a hydrophilic function.

[0089] By subjecting the ozone oxidation catalyst to hydrophilic treatment, an ozone oxidation catalyst with hydrophilic function is prepared, which enhances its ability to adsorb ozone and organic matter dissolved in wastewater, thereby further improving the adsorption capacity of the ozone oxidation catalyst and its catalytic oxidation capacity for ozone.

[0090] In one embodiment of the present invention, the first binder in sub-step 1) is sodium carboxymethyl cellulose (CMC) and / or sodium alginate (SA). The water-soluble first binder contains more hydroxyl groups, which can generate a large number of hydrogen bonds between the ozone oxidation catalyst and itself, so that it can be well bonded to the ozone oxidation catalyst, so as to better play its hydrophilic adsorption role. In addition, by controlling the amount of the first binder, the hydrophilicity of the catalyst can also be controlled within a certain range, so that the dissolved ozone and hydrophilic organic matter in the wastewater can be well adsorbed, and the hydrophilic organic matter and dissolved ozone can be fully contacted and reacted.

[0091] Preferably, the first binder in sub-step 1) is sodium carboxymethylcellulose (CMC).

[0092] In one embodiment of the present invention, the mass ratio of the ozone oxidation catalyst to the first binder is set to 1:(0.01-0.2).

[0093] Preferably, the mass ratio of the ozone oxidation catalyst to the first binder is set to 1:0.1.

[0094] In one embodiment of the present invention, the water content of the first paste in step 1) is controlled to be 15-20 wt%. The preparation of the first paste is mainly to facilitate the material to enter the granulator for granulation.

[0095] In one embodiment of the present invention, the temperature range of drying the first particles in sub-step 2) is 100-120° C., and the drying time is 1 hour.

[0096] In one embodiment of the present invention, after step (5), a step (7) of hydrophobic treatment of the ozone oxidation catalyst is included, and step (7) includes:

[0097] 3) After mixing the ozone oxidation catalyst and the second binder, adding an appropriate amount of water to obtain a second paste, wherein the second binder is a hydrophobic organic substance;

[0098] 4) The second paste is used as a raw material to perform granulation to obtain second particles, and the second particles are heat-treated to obtain an ozone oxidation catalyst having a hydrophobic function.

[0099] By subjecting the ozone oxidation catalyst to hydrophobic treatment, an ozone oxidation catalyst with hydrophobic function is prepared, which enhances its adsorption capacity for ozone not dissolved in wastewater, thereby further improving the adsorption capacity of the ozone oxidation catalyst and the catalytic oxidation capacity for ozone.

[0100] In one embodiment of the present invention, the heat treatment in sub-step 4) includes two stages, the treatment temperature range of the first stage is 300-400°C, and the treatment temperature range of the second stage is 100-120°C. Through the two-stage heat treatment, the second binder can be melted at high temperature to form a waterproof layer, and the combination with the ozone oxidation catalyst is more tightly. Then, the granular carbon material is further dried to form an ozone oxidation catalyst with hydrophobic properties.

[0101] Preferably, the heat treatment time of the second particles in the first stage is 10 min-20 min.

[0102] Preferably, the heat treatment time of the second particles in the second stage is 1-2 hours.

[0103] Preferably, the second particles are heat treated in the second stage until the difference between two mass measurements is less than 5 mg, ie, dried to a constant weight.

[0104] In one embodiment of the present invention, the second binder is a polytetrafluoroethylene (PTFE) solution with a content of (10-15 wt%). The degree of polymerization of the polytetrafluoroethylene is not limited as long as the hydrophobicity of the catalyst can be changed.

[0105] In a preferred embodiment of the present invention, the degree of polymerization of polytetrafluoroethylene (PTFE) in the polytetrafluoroethylene (PTFE) solution is 10 4 Order of magnitude.

[0106] In one embodiment of the present invention, the mass ratio of the ozone oxidation catalyst to the second adhesive is 1:(0.01-0.2).

[0107] Preferably, the mass ratio of the ozone oxidation catalyst to the second adhesive is 1:0.1.

[0108] In one embodiment of the present invention, the second binder is a polytetrafluoroethylene aqueous solution, and no additional water is needed in sub-step 3).

[0109] According to the preparation method of the ozone oxidation catalyst of the present invention, the operation of step (1) to step (5) makes the prepared ozone oxidation catalyst have more microporous structures and more pyridine-N that can provide active sites for ozone catalytic oxidation. Finally, the prepared ozone oxidation catalyst has a stronger adsorption capacity for ozone and organic matter in wastewater, thereby enhancing the efficiency of ozone catalytic oxidation in the wastewater treatment process. In addition, through the operation of step (6) and step (7), the prepared ozone oxidation catalyst can be treated with hydrophilicity and hydrophobicity to prepare an ozone oxidation catalyst with hydrophilic and hydrophobic functions, thereby respectively improving the adsorption capacity of the catalyst for ozone dissolved in water and ozone not dissolved in water, thereby helping to improve the ozone catalytic oxidation ability of the ozone oxidation catalyst prepared by the preparation method of the present invention. In addition, compared with the preparation method of directly activating the sludge and then pyrolyzing it, the yield of the preparation method according to the present invention can be increased by more than 5%, so that the technical solution provided by the present invention has higher economic efficiency.

[0110] According to a second aspect of the present invention, a catalyst is provided.

[0111] The catalyst is prepared by the above-mentioned preparation method of the ozone oxidation catalyst.

[0112] The catalyst according to the present invention has more microporous structures and more pyridine-N that can provide active sites for ozone catalytic oxidation, so it has a stronger adsorption capacity for ozone and organic matter in wastewater, thereby enhancing the efficiency of ozone catalytic oxidation in the wastewater treatment process. In addition, the present invention also provides a catalyst with hydrophilicity and hydrophobicity, so that the adsorption capacity of the catalyst for ozone dissolved in water and ozone not dissolved in water can be improved respectively, thereby helping to improve the catalyst's ability to catalytically oxidize ozone.

[0113] In addition, the catalyst according to the present invention also has other technical effects that can be produced by the preparation method of the ozone oxidation catalyst according to the present invention, which will not be described in detail here.

[0114] According to a third aspect of the present invention, a method for using a catalyst is provided.

[0115] The method for using the catalyst comprises the following steps:

[0116] The catalysts as described above are used in a layered stack arrangement.

[0117] The method of using the catalyst according to the present invention can produce the technical effect that the catalyst according to the present invention can produce, and will not be elaborated here.

[0118] like Figure 2 As shown, in one embodiment of the present invention, several layers of catalysts with hydrophilic function are stacked on or below several layers of catalysts with hydrophobic function. Since the catalysts with hydrophilic function and the catalysts with hydrophobic function are used in combination, the hydrophilic catalyst is good at capturing ozone and organic matter dissolved in the wastewater, and the hydrophobic catalyst is good at capturing ozone not dissolved in the wastewater, thereby greatly improving the utilization rate of ozone, thereby improving the efficiency of catalytic oxidation, and finally improving the wastewater treatment capacity.

[0119] like Figure 3 As shown, in one embodiment of the present invention, a catalyst with a hydrophilic function and a catalyst with a hydrophobic function are arranged in layers and stacked for use. Since the catalyst with a hydrophilic function and the catalyst with a hydrophobic function are used in combination, the hydrophilic catalyst is good at capturing ozone and organic matter dissolved in the wastewater, and the hydrophobic catalyst is good at capturing ozone that is not dissolved in the wastewater, thereby greatly improving the utilization rate of ozone, thereby improving the efficiency of catalytic oxidation, and ultimately improving the wastewater treatment capacity.

[0120] Preferably, if Figure 4As shown, the catalyst with a hydrophilic function and the catalyst with a hydrophobic function are arranged in layers and stacked at intervals, and the catalyst with a hydrophilic function and the catalyst with a hydrophobic function have different outer diameters. In this embodiment, since the catalyst with a hydrophilic function and the catalyst with a hydrophobic function have different outer diameters, the catalyst with a hydrophilic function and the catalyst with a hydrophobic function are nested with each other, thereby making the stacking volume of the catalyst smaller, which is beneficial to improving the space utilization inside the wastewater treatment device.

[0121] According to a fourth aspect of the present invention, a wastewater treatment method using a wastewater treatment device is provided.

[0122] The wastewater treatment method using a wastewater treatment device uses the catalyst as described above and utilizes a wastewater treatment device 100 . The wastewater treatment device 100 includes a tower body 1 and a treatment unit 2 .

[0123] In this embodiment, the tower body 1 is configured as a cylindrical tube, and spherical surfaces are configured at the upper and lower ends of the tower body 1. Other tower body shapes can be used according to the prior art.

[0124] A water inlet 11 is provided at the upper part of the tower body 1, and a water outlet 12 is provided at the lower part of the tower body 1. Specifically, the water inlet 11 is provided at the top end of the cylindrical side of the tower body 1, and the water outlet 12 is provided at the bottom end of the cylindrical side of the tower body 1.

[0125] The processing unit 2 is disposed inside the tower body 1 , and the processing unit 2 is located between the water inlet 11 and the water outlet 12 .

[0126] The processing unit 2 includes a valve tray 21, an air intake assembly 22 and a catalytic tray 23. The valve tray 21 is arranged below the water inlet 11, the air intake assembly 22 is arranged below the valve tray 21, the catalytic tray 23 is arranged below the air intake assembly 22, and the catalyst as described above is loaded on the catalytic tray 23.

[0127] Under this arrangement, wastewater enters the tower body 1 from the water inlet 11 and flows onto the float valve plate 21. At the same time, ozone enters the tower body 1 through the air inlet assembly 22 and flows upward, passing through the float valve plate 21 and dissolving in the wastewater on the float valve plate 21. Then, the wastewater dissolved with ozone flows downward to the catalytic plate 23, flows downward again after catalysis, and is discharged from the water outlet 12.

[0128] In a preferred embodiment, a liquid inlet baffle 13 is provided in the tower body 1. Specifically, Figure 5 As shown, the cross section of the liquid inlet baffle 13 is set to be L-shaped. The liquid inlet baffle 13 is located at the water inlet 11 and is used to limit the distance that the wastewater is sprayed in the horizontal direction after entering from the water inlet 11.

[0129] Meanwhile, a baffle 213 is provided on the upper end surface of the valve tray 21 . The baffle 213 is located between the water inlet 11 and the valve body 214 of the valve tray 21 . Furthermore, the baffle 213 is located between the liquid inlet baffle 13 and the valve body 214 .

[0130] Under this arrangement, after the wastewater enters the tower body 1 from the water inlet 11, it falls onto the floating valve tray 21 on the side of the baffle 213 away from the valve body 214 under the action of the liquid inlet baffle 13. When the height of the wastewater exceeds the baffle 213, the wastewater can pass over the baffle 213 and flow to the side of the floating valve tray 21 where the valve body 214 is arranged.

[0131] After the liquid inlet baffle 13 and the baffle bar 213 are provided, the area on the left side of the baffle bar 213 can play a buffering role, so that the wastewater can be more evenly distributed in the area where the valve body 214 is provided on the floating valve tower plate 21, thereby allowing ozone to be better dissolved in the wastewater. In a specific embodiment, the air intake assembly 22 includes an air distribution pipe 221 and a flange 222, such as Figure 6 shown.

[0132] Combination Figure 5 and Figure 6 As shown, an air inlet 14 is provided on the tower body 1, a flange 222 is provided at the end of an air distribution pipe 221, and the air distribution pipe 221 is installed at the air inlet 14 through the flange 222, so that ozone can pass through the air inlet 14, the flange 222 and the air distribution pipe 221 in sequence, and finally enter the tower body 1.

[0133] After entering the tower body 1, the ozone moves upward and passes through the float valve tray 21. The valve body 214 on the float valve tray 21 opens under the force of the ozone. At the same time, the ozone flows horizontally under the action of the valve body 214, thereby dissolving with the wastewater on the float valve tray 21. Under this setting, the ozone and the wastewater can have a large contact area, thereby accelerating the speed at which the ozone dissolves into the wastewater.

[0134] It is easy to understand that the structure of the floating valve tray 21 is prior art and will not be described in detail here.

[0135] In a preferred embodiment, the air distribution pipe 221 is provided in a cylindrical shape with one end blocked. Figure 6 As shown, the right end of the gas distribution pipe 221 is closed, the left end is open, and the left end opening of the gas distribution pipe 221 is fixedly connected to the flange 222. A plurality of air holes 223 are evenly distributed on the cylindrical surface of the gas distribution pipe 221, and ozone enters the tower body 1 through the plurality of air holes 223, thereby ensuring that the ozone distribution in the entire cross section of the floating valve tower plate 21 is even.

[0136] In a preferred embodiment, the combination Figure 5 and Figure 7As shown, the float valve tray 21 is an incomplete circle, and the incomplete portion of the float valve tray 21 is located at an end away from the water inlet 11, and the incomplete portion of the float valve tray 21 is set as the first channel opening 215. A float valve overflow weir 211 and a float valve downcomer 212 are arranged along the vertical direction at the end of the float valve tray 21 away from the water inlet 11, that is, the first channel opening 215 is located between the float valve overflow weir 211 and the tower body 1, and between the float valve downcomer 212 and the tower body 1.

[0137] The float valve overflow weir 211 is disposed above the float valve tray 21 to limit the liquid level of the float valve tray 21 .

[0138] The float valve downcomer 212 is disposed below the float valve tray 21 to guide the wastewater flowing downward.

[0139] After the wastewater flows onto the float valve tower plate 21, under the action of the float valve overflow weir 211, the wastewater accumulates on the float valve tower plate 21 until the height of the wastewater is level with the height of the float valve overflow weir 211, and then the wastewater continues to flow from the water inlet 11 to the float valve tower plate 21, and then flows downward from the first channel port 215 over the float valve overflow weir 211, and finally flows downward to the catalytic tower plate 23 under the guidance of the float valve downcomer plate 212, and undergoes ozone catalytic oxidation on the catalytic tower plate 23.

[0140] In a specific embodiment, the catalytic tray 23 includes a support plate 231 and a catalyst 232 disposed on the support plate 231 . The catalyst 232 is selected as the catalyst described above.

[0141] Specifically, the support plate 231 is also set to an incomplete circle, and the incomplete portion of the support plate 231 is set to a second channel opening 235. Unlike the floating valve tower plate 21, the incomplete portion of the support plate 231 is set near the water inlet 11, that is, the second channel opening 235 is set on the side of the support plate 231 near the water inlet 11.

[0142] Under this arrangement, the wastewater remaining on the float valve tray 21 will flow to the upper right side of the support plate 231 , and then flow from right to left, thereby fully contacting the catalyst 232 on the support plate 231 .

[0143] At the left end of the support plate 231, that is, the right end of the second channel opening 235, a catalytic overflow weir 233 and a catalytic downcomer plate 234 arranged in the vertical direction are fixed. The catalytic overflow weir 233 is arranged above the support plate 231 to limit the liquid level on the support plate 231 and provide time for the wastewater containing ozone to fully contact with the catalyst 232. The catalytic downcomer plate 234 is arranged below the support plate 231 to guide the wastewater flowing downward.

[0144] When the wastewater level on the support plate 231 exceeds the catalytic overflow weir 233 , the wastewater flows over the catalytic overflow weir 233 and flows downward through the second channel opening 235 under the guidance of the catalytic downcomer plate 234 .

[0145] In a preferred embodiment, the lowest point of the float valve downcomer 212 is lower than the highest point of the catalytic overflow weir 233. When the wastewater containing ozone falls onto the support plate 231 and the height of the wastewater is flush with the height of the catalytic overflow weir 233, the lower end of the float valve downcomer 212 will be immersed in the wastewater. Under the action of the float valve downcomer 212, the wastewater can flow through the catalyst layer 232 from low to high and fully contact the catalyst layer 232, thereby accelerating the reaction rate.

[0146] In a specific embodiment, based on the fact that the lowest point of the float valve downcomer 212 is lower than the highest point of the catalytic overflow weir 233, the distance from the lowest point of the float valve downcomer 212 to the support plate 231 is not less than the size of a single catalyst 232 particle, thereby ensuring fluidity.

[0147] In a preferred embodiment provided according to the present invention, a plurality of treatment units 2 are sequentially arranged from top to bottom in the tower body 1. The structure of each treatment unit 2 can refer to the structure of the treatment unit 2 in the above embodiment. Under this arrangement, the plurality of treatment units 2 cooperate with each other to perform repeated ozone catalytic oxidation on the wastewater, thereby improving the effect of wastewater treatment.

[0148] When multiple processing units 2 cooperate with each other, the catalytic downcomer 234 of the upper processing unit 2 is equivalent to the role of the inlet baffle 13 at the water inlet 11 for the lower processing unit 2. In other words, the catalytic downcomer 234 of the upper processing unit is located on the side of the baffle 213 of the lower processing unit 2 away from the valve body 214.

[0149] At the same time, a plurality of inspection ports 15 are provided on the cylindrical side wall of the tower body 1, and the number and position of the inspection ports 15 correspond one-to-one with the processing units 2. In this embodiment, the inspection ports 15 are provided on the side of the tower body 1 away from the water inlet 11, such as Figure 5 As shown, the water inlet 11 is arranged at the leftmost side of the tower body 1 , and each inspection port 15 is arranged at the rightmost side of the tower body 1 .

[0150] Furthermore, at least three processing units 2 are sequentially arranged in the tower body 1 from top to bottom. In this embodiment, a total of three processing units 2 are arranged. Figure 5 As shown, an ozone collecting port 16 is provided at the top of the tower body 1, and the ozone collecting port 16 is connected to the air intake assembly 22 of the processing unit 2 located at the bottom, and the air intake assemblies 22 of the remaining processing units 2 are connected to the ozone generator (not shown, the same below).

[0151] Under this arrangement, ozone that has not dissolved in wastewater can pass through the ozone collection port 16 and enter the lowest treatment unit 2, and continuously dissolve with wastewater while flowing upward along the tower body 1, thereby improving the utilization rate of ozone.

[0152] In one embodiment of the present invention, in order to improve the treatment effect of the ozone oxidation catalyst on wastewater, the catalyst as described above loaded on the support plate 231 in the catalytic tray 23 is used according to the method of using the catalyst as described above.

[0153] Preferably, the catalysts 232 on the support plates 231 in the catalytic tray 23 are stacked and arranged in layers for use.

[0154] Preferably, the catalyst 2321 with a hydrophilic function and the catalyst 2322 with a hydrophobic function are stacked and arranged in layers on the support plate 231 of the catalytic tray 23 for use.

[0155] Preferably, the catalyst 2321 with a hydrophilic function and the catalyst 2322 with a hydrophobic function are arranged in layers and stacked at intervals for use, and the catalyst 2321 with a hydrophilic function and the catalyst 2322 with a hydrophobic function have different outer diameters.

[0156] The arrangement of the catalyst 232 in the above embodiment can be referred to Figures 2 to 4 , and the above embodiment can also achieve other technical effects that can be achieved by the method of using the catalyst as described above, which will not be repeated here.

[0157] In another embodiment of the present invention, the wastewater treatment device 100 has the same components and configuration as those of the above embodiment except that the configuration of the catalytic tray 23 is different from that of the above embodiment.

[0158] refer to Figure 8 and Fig. 9 The catalytic tray 23 includes: a support plate 231 for placing a catalyst 232 and a first baffle 271. The first baffle 271 is a thin plate, and its two surfaces are curved. Fig. 9 As shown, the cross section is S-shaped.

[0159] One side of the first baffle plate 271 presenting a straight line is connected to the support plate 231, and the angle formed by the first baffle plate 271 and the support plate 231 is 0°<α≤90°. Figure 8 and Fig. 9 As shown, the angle formed by the first baffle 271 and the support plate 231 is 90° as a whole. Since the first baffle 271 is curved in the vertical direction of the tower body 1, such as an S-shaped baffle, its overall structural profile is greater than 90° with the support plate.

[0160] A plurality of curved first baffles 271 are provided, and the connection points between the plurality of first baffles 271 and the support plate 231 are substantially perpendicular to the overall flow direction of the waste liquid on the support plate 231 .

[0161] The length of the side connecting each first baffle 271 and the support plate 231 is the same as the length of the support plate 231 at the corresponding position. For example, in order to contact the peripheral wall of the tower body, the width of the support plate 231 perpendicular to the water flow direction may be changed, so the length of the first baffle 271 needs to be adjusted accordingly.

[0162] In a preferred solution, a second baffle plate 272 is further provided between the two first baffle plates 271 .

[0163] The shape of the second baffle 272 is the same as that of the first baffle 271 .

[0164] One straight side of the second baffle plate 272 is connected to the frame support beam 25 above the support plate 231 , and the other opposite side has a gap with the support plate 231 .

[0165] In the vertical direction in the tower body 1, the cross section of the second baffle plate 272 is a curved shape, for example, a baffle plate with an S-shaped cross section.

[0166] The plate surface of the second baffle plate 272 is substantially perpendicular to the overall flow direction of the wastewater on the support plate 231 .

[0167] The angle formed by the second baffle plate 272 and the support plate 231 is 0°<α≤90°. The angle formed by the second baffle plate 272 and the support plate 231 is 90° as a whole.

[0168] The frame beam 25 may be a frame structure or composed of a plurality of beams, and the frame beam 25 is connected to the support plate through one or more support rods 26. The frame beam may also be other structures as long as the second baffle 271 can be fixed above the support plate and used to install the second baffle 272.

[0169] Preferably, the side of the first baffle plate 271 away from the support plate 231 is lower than the frame beam, that is, lower than the uppermost side of the second baffle plate 272 .

[0170] Wastewater flows into the floating valve tray 21 through the water inlet 11, flows toward the floating valve downcomer 212 along the first direction, and is mixed with the ozone entering from the gas distribution pipe; the gas-liquid mixture flows along the floating valve downcomer 212 to the catalytic tray 23, and flows toward the catalytic downcomer 234 of the catalytic tray 23 along the second direction, wherein the first flow direction is opposite to the second flow direction. On the catalytic tray 23, the gas-liquid mixture enters into a plurality of interval areas formed by the first baffle 271 or the first baffle 271 and the second baffle 272, forming turbulence of different degrees, and the catalyst 232 particles move in multiple directions in the turbulent area, increasing the contact area and contact time with the gas-liquid mixture, thereby improving the removal efficiency of organic matter in the wastewater.

[0171] In a more preferred embodiment, the vertical cross-section of the first baffle 271 and the second baffle 272 includes at least two arcs, and the openings of adjacent arcs are arranged oppositely. Fig. 9 As shown, the cross-sections of the first baffle plate 271 and the second baffle plate 272 include a first arc section and a second arc section, and the first arc section and the second arc section have a smooth transition.

[0172] The curvature of the first arc section and the second arc section of the first and second baffles (271, 272) gradually increases from the end to the middle.

[0173] In order to allow the mixed water to flow smoothly through the catalyst 232 and to promote the gas, liquid and solid phases to fully contact each other and react, the opening directions of the first arc section and the second arc section of each first and second baffles (271, 272) are consistent.

[0174] When the water flows through the support plate 231 of the catalytic tower plate 23, the water flows through the different curved surfaces of the first baffle plate 271 and the second baffle plate 272, and the water flows along the tangential directions of the baffle plates in different directions, disturbing the flipping of the catalyst 232 particles, thereby promoting the multi-dimensional contact of the catalyst 232 particles with the wastewater and ozone.

[0175] Furthermore, in the horizontal direction, the lowermost end of the second baffle 272 is basically located in the middle of the second arc section of the first baffle 271; the uppermost end of the first baffle 271 is basically located in the middle of the first arc section of the second baffle 272. The middle of the first arc section of the first baffle 271 is flush with the middle point of the second arc section of the second baffle 272. An uneven longitudinal flow velocity is formed on the transverse cross section in each interval of the catalytic tower plate 23, which agitates the catalyst 232 particles. Since the catalyst 232 can be agitated to flip up and down, the contact area between the catalyst 232 particles and the ozone diffused to the catalytic tower plate 23 is increased, further allowing the ozone, wastewater and catalyst particles to fully contact and react. The utilization rate of ozone and the efficiency of removing organic matter in wastewater are improved.

[0176] In another embodiment, the cross-sections of the first baffle 271 and the second baffle 272 in the vertical direction are linear, and the angle formed with the support plate is greater than 0° and less than 90°. The tangent directions of the first baffle 271 and the second baffle 272 are opposite.

[0177] The wastewater treatment process using the above-mentioned wastewater treatment device 100 includes: in the treatment unit 2, the wastewater and ozone are in cross-flow, the ozone passes through the float valve tower plate 21 from bottom to top and enters into the wastewater, and the wastewater flows into the catalytic tower plate 23 through the float valve downcomer plate 212. Under the action of the catalyst 232, the dissolved ozone is excited to produce free radicals, which plays a role in degrading organic matter.

[0178] Specifically, wastewater flows from a wastewater tank (not shown, the same below) into the tower body 1 under the action of a centrifugal pump (not shown, the same below). After the wastewater enters the tower body 1 from the water inlet 11, it falls onto the floating valve tower plate 21 of the uppermost treatment unit 2, and falls to the area located on the left side of the baffle 213 under the action of the liquid inlet baffle 13.

[0179] After the liquid level exceeds the baffle 213, it flows into the float valve area, that is, the area of ​​the float valve plate 21 where the valve body 214 is provided. At the same time, ozone enters the tower body 1 from the air inlet 14 via the air distribution pipe 221. The ozone sprayed from the air distribution pipe 221 passes through the valve body 214 on the float valve plate 21, and the size of the opening and closing of the valve body 214 can be adjusted by adjusting the size of the ozone flow rate. After passing through the valve body 214, the ozone is mass-transferred with the wastewater on the float valve plate 21, and the undissolved ozone rises to the ozone collection port 16. The wastewater in which ozone has been dissolved slowly flows through the float valve overflow weir 211, and flows into the catalytic plate 23 through the float valve downcomer 212. After the wastewater in which ozone has been dissolved enters the catalytic plate 23, under the action of the catalyst 232, the ozone is excited to produce free radicals, which react with the organic matter in the wastewater to achieve the effect of removing the organic matter.

[0180] The ozone flow rate of the treatment units 2 at the top and middle layers is controlled by an ozone flow controller (not shown, the same below). The ozone flow rate of each layer of treatment unit 2 is determined according to the initial concentration of the wastewater received by each layer of treatment unit 2 and the size of the droplets formed on the float valve tray 21, and is generally controlled at 5-20 m / s.

[0181] Finally, the wastewater is treated by the three treatment units 2 and then discharged from the outlet 12 .

[0182] Undissolved ozone rises to the ozone collection port 16, and after being collected, it returns to the tower body 1 through the air intake assembly 22 of the processing unit 2 located at the bottom layer under the action of a fan (not shown, the same below), and continues to participate in the ozone catalytic oxidation reaction process.

[0183] According to the wastewater treatment method using the wastewater treatment device of the present invention, the floating valve tray 21 is used to promote the mass transfer of ozone and wastewater, replacing the traditional aeration. When the gas phase passes through the valve body 214 on the floating valve tray 21, the wastewater on the surface of the floating valve tray 21 is dispersed into droplets, the gas-liquid contact mass transfer area is increased, and the gas-liquid mass transfer rate is accelerated, so that more ozone is dissolved in the wastewater. Furthermore, combined with the improvement of the catalyst 232, the gas, liquid and solid three phases are better contacted and reacted, thereby improving the utilization rate of ozone and the wastewater treatment efficiency.

[0184] Furthermore, the wastewater treatment method using the wastewater treatment device according to the present invention utilizes a multi-layer tower plate combination to divide a treatment unit into three parts: upper, middle and lower. Multiple treatment units are then arranged in a vertical direction, thereby reducing infrastructure investment and floor space.

[0185] In addition, in the wastewater treatment method using the wastewater treatment device according to the present invention, the undissolved ozone re-enters the treatment unit 2 through the ozone collection port 16 to be reused, replacing the ozone destruction device in the prior art. No pressurized gas release device is required, and the ozone utilization efficiency is high.

[0186] The wastewater treatment method using the wastewater treatment device according to the present invention can also achieve other technical effects that can be achieved by the catalyst according to the present invention, which will not be described in detail here.

[0187] The technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0188] The oil sludge in the following examples comes from the tank bottom oil sludge of a certain oil field, and the main substances and element contents are shown in Table 1:

[0189] Table 1 Sludge composition

[0190]

[0191] Ash, volatile matter, and fixed carbon content were obtained by industrial analysis, and elemental composition was obtained by elemental analysis.

[0192] The wastewater to be treated in the following examples is gas field produced water.

[0193] The main components of COD in gas field produced water are aromatic compounds such as aniline and phenol, saturated hydrocarbons, and nitrogen-containing heterocyclic compounds.

[0194] Comparative Example 1:

[0195] The dried sludge (containing 3% water) is mixed with an activator in a certain mass ratio, and the activator is KOH. The mass ratio of sludge to activator is 1:3. Activate at room temperature for 2 hours. Under a nitrogen atmosphere, the obtained product is pyrolyzed at 600°C for 2 hours. This step can obtain a third carbon powder. The obtained third carbon powder is mixed with sodium carboxymethyl cellulose (CMC) in a mass ratio of 1:0.1, and an appropriate amount of water is added to obtain a paste (with a water content of 15%). The paste is granulated with a granulator to obtain round granular carbon, and the oven is heated to 100-120°C and dried for 1 hour, which is a hydrophilic ozone oxidation catalyst prepared by the prior art.

[0196] The hydrophilic ozone oxidation catalyst prepared by the prior art was subjected to specific surface area and XPS functional group tests, and the results are shown in Table 2.

[0197] The following experiment was conducted using the hydrophilic ozone oxidation catalyst prepared by the above method:

[0198] The hydrophilic ozone oxidation catalyst was filled to 1 / 3 of the volume of the ozone catalytic oxidation column (20 cm in diameter, 80 cm in length), and the wastewater accounted for 3 / 4 of the volume of the ozone catalytic oxidation column. The ozone flow rate was 0.5 L / min, the ozone concentration was 60 mg / L, and the wastewater used was gas field produced water with an initial COD of 1500 mg / L. After 2 hours of treatment, the COD removal rate was 41%.

[0199] Comparative Example 2:

[0200] The sludge is dried to constant weight and pyrolyzed at 600°C for 2h under a nitrogen atmosphere. After being taken out and cooled, the ash is washed off with 3mol / L dilute hydrochloric acid, filtered and dried to obtain the fourth carbon powder. The fourth carbon powder is mixed with an activator in a certain mass ratio, the activator is KOH, and the mass ratio of the fourth carbon powder to the activator KOH is 1:3. Activate at room temperature for 2h. Under a nitrogen atmosphere, the resulting product is pyrolyzed at 600°C for 2h. This step can obtain a fifth carbon powder with rich pores and developed micropores. The obtained fifth carbon powder is mixed with sodium carboxymethyl cellulose (CMC) in a mass ratio of 1:0.1, and an appropriate amount of water is added to obtain a paste (water content of 15%). The paste is granulated by a granulator to obtain round granular carbon, the oven is heated to 100-120°C, and dried for 1h, which is another hydrophilic ozone oxidation catalyst prepared by the prior art.

[0201] The hydrophilic ozone oxidation catalyst prepared by the prior art was subjected to specific surface area and XPS functional group tests, and the results are shown in Table 2.

[0202] The following experiment was conducted using the hydrophilic ozone oxidation catalyst prepared by the above method:

[0203] The above ozone oxidation catalyst was filled to 1 / 3 of the volume of the ozone catalytic oxidation column (20cm in diameter, 80cm in length), and the wastewater accounted for 3 / 4 of the volume of the ozone catalytic oxidation column. The ozone flow rate was 0.5L / min, the ozone concentration was 60mg / L, and the wastewater used was gas field produced water with an initial COD of 1500mg / L. After 2h of treatment, the COD removal rate was 45%.

[0204] Embodiment 1:

[0205] The sludge is dried to constant weight, and the first pyrolysis is carried out for 2 hours under the conditions of nitrogen atmosphere and pyrolysis temperature of 600°C. After being taken out and cooled, the ash is washed off with 3mol / L dilute hydrochloric acid, filtered and dried to obtain the first carbon powder. The first carbon powder is mixed with an activator in a certain mass ratio, the activator is KOH, and the mass ratio of carbon powder 1 to activator KOH is 1:3. After activation at room temperature for 2 hours, the first transition product is obtained. Under a nitrogen atmosphere, the first transition product is subjected to a second pyrolysis at a pyrolysis temperature of 600°C for 2 hours. This step can obtain a second carbon powder with rich pores and developed micropores. The second carbon powder is mixed with urea and treated for 2 hours, and the mass ratio of carbon powder to urea is 1:0.5 to obtain a second transition product. Under a nitrogen atmosphere, the second transition product is subjected to a third pyrolysis at a pyrolysis temperature of 600°C for 2 hours. This step can obtain a catalyst according to the present invention rich in nitrogen functional groups (pyridine-N and CN). The obtained catalyst is mixed with sodium carboxymethyl cellulose (CMC) at a mass ratio of 1:0.1, and an appropriate amount of water is added to obtain a first paste (water content is 15%). The first paste is granulated by a granulator to obtain round first particles, and the oven is heated to 100-120° C., and the first particles are dried for 1 hour to obtain a hydrophilic catalyst according to the present invention.

[0206] The specific surface area and XPS functional group tests of the hydrophilic catalyst according to the present invention are performed, and the results are shown in Table 2.

[0207] The following experiment was carried out using the hydrophilic catalyst prepared by the above method:

[0208] The hydrophilic catalyst was filled to 1 / 3 of the volume of the ozone catalytic oxidation column (20 cm in diameter, 80 cm in length), and the wastewater accounted for 3 / 4 of the volume of the ozone catalytic oxidation column. The ozone flow rate was 0.5 L / min, and the ozone concentration was 60 mg / L. The wastewater used was gas field produced water, and its initial COD was 1500 mg / L. After 2 hours of treatment, the COD removal rate was 62%.

[0209] Embodiment 2:

[0210] The sludge is dried to constant weight, and the first pyrolysis is carried out for 2 hours under the conditions of nitrogen atmosphere and pyrolysis temperature of 600°C. After being taken out and cooled, the ash is washed off with 3mol / L dilute hydrochloric acid, filtered and dried to obtain the first carbon powder. The first carbon powder is mixed with an activator in a certain mass ratio, the activator is KOH, and the mass ratio of the first carbon powder to the activator KOH is 1:3. After activation for 2 hours, the first transition product is obtained. Under a nitrogen atmosphere, the first transition product is subjected to a second pyrolysis at a pyrolysis temperature of 600°C for 2 hours. This step can obtain a second carbon powder with rich pores and developed micropores. The second carbon powder is mixed with urea and treated for 2 hours, and the mass ratio of carbon powder to urea is 1:0.5 to obtain a second transition product. Under a nitrogen atmosphere, the second transition product is subjected to a third pyrolysis at a pyrolysis temperature of 600°C for 2 hours. This step can obtain a catalyst according to the present invention rich in nitrogen functional groups (pyridine-N and CN).

[0211] The catalyst according to the present invention is mixed with sodium carboxymethyl cellulose (CMC) in a mass ratio of 1:0.1, and an appropriate amount of water is added to obtain a first paste (water content is 15%). The first paste is granulated by a granulator to obtain round first particles, the oven is heated to 100-120°C, and the first particles are dried for 1 hour to obtain a hydrophilic catalyst according to the present invention. The catalyst according to the present invention is mixed with a polytetrafluoroethylene (PTFE) solution with a content of 15% to obtain a second paste, wherein the mass ratio of the catalyst according to the present invention to PEFE is 1:0.1. The second paste is granulated by a granulator to obtain round second particles. The second particles are heat treated at a temperature of 350°C for 15 minutes, cooled to 100°C for drying, and the hydrophobic catalyst according to the present invention is obtained after cooling.

[0212] The following experiments were carried out using the catalyst prepared by the above method:

[0213] The catalyst filled 1 / 3 of the ozone catalytic oxidation column (20cm in diameter, 80cm in length), with the hydrophilic catalyst located below the hydrophobic catalyst. The two catalysts each occupied 1 / 6 of the column volume, and the wastewater occupied 3 / 4 of the ozone catalytic oxidation column volume. The ozone flow rate was 0.5L / min, the ozone concentration was 60mg / L, and the wastewater used was gas field produced water, with an initial COD of 1500mg / L. After 2h of treatment, the COD removal rate was 81%.

[0214] Experimental Example 1

[0215] The pores of the catalysts obtained in Comparative Example 1, Comparative Example 2 and Example 3 were detected using a BET specific surface area tester, and the elements of the catalysts were determined using an X-ray photoelectron spectrometer (XPS), as shown in Table 2.

[0216] The micropores in the table are pores with a pore diameter less than 2.0 nm, and the micropore volume ratio represents the proportion of micropores to all pores. As can be seen from Table 2, the catalyst obtained by the preparation method of the present invention has more micropores than the prior art.

[0217] Table 2 Specific surface area and pyridine nitrogen content of catalysts prepared by different methods (XPS calculation results)

[0218]

[0219] In addition, other elements in the catalyst of Example 1 were further detected by X-ray photoelectron spectroscopy (XPS). The results are shown in Table 3.

[0220] Table 3

[0221]

[0222] It can be concluded from Comparative Examples 1 and 2, Examples 1 and 2 and Experimental Example 1 that the ozone oxidation catalyst prepared by the preparation method of the ozone oxidation catalyst according to the present invention has a richer microporous structure, a larger specific surface area and more active sites compared with the prior art, and thus has a stronger adsorption capacity for ozone and organic matter in wastewater, and thus has a higher wastewater treatment efficiency.

[0223] It should be noted that the directional terms or qualifiers "upper", "lower", "front", "back", "left", "right", etc. used in this application are all relative to the referenced Figure 5 They are not intended to define the absolute positions of the components involved, but may vary depending on the specific circumstances.

[0224] The wastewater treatment device of the present invention mainly utilizes ozone to oxidize COD (full name "Chemical Oxygen Demand") in wastewater, which specifically refers to the amount of oxidant consumed when a certain strong oxidant is used to treat a water sample under certain conditions. The reducing substances in water are mainly organic substances, so COD is generally used to represent the total amount of organic substances in wastewater.

[0225] The oil sludge in the present invention is the oil sludge from the bottom of the tank of the oil production plant, and its components mainly contain a large amount of crude oil (including saturated hydrocarbons, aromatic hydrocarbons, non-hydrocarbons, asphaltenes), inorganic mineral suspended particles, formation water, and various chemical agents.

[0226] Pyrolysis: refers to the reaction process in which a substance decomposes when heated. Many inorganic and organic substances will decompose when heated to a certain degree.

[0227] Room temperature: The room temperature in this application generally refers to a temperature between 15-27°C.

[0228] Gas field wastewater refers to wastewater generated by gas field exploitation operations, such as drilling wastewater, fracturing flowback fluid and gas field water.

[0229] Gas field produced water (also called gas field water) is mainly water that is associated with gas and has the characteristics of formation water. At the same time, due to the addition of some chemicals in the early stage of the operation, such as fungicides, foaming agents, emulsifiers, etc., the COD in the produced water is relatively high, and most of them are large molecular substances that are difficult to degrade.

[0230] In the drying process of the preparation process of the present invention, unless otherwise specified, the substance to be dried is dried to a constant weight.

[0231] Finally, it should be noted that the above is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an ozone oxidation catalyst, comprising the following steps: (1) performing a first pyrolysis on the dried oil sludge in an inert atmosphere to obtain a first carbon powder; (2) mixing the first carbon powder with an activator and activating the mixture to obtain a first transition product; (3) subjecting the first transition product to a second pyrolysis in an inert atmosphere to obtain a second carbon powder; (4) mixing the second carbon powder with urea to obtain a second transition product; (5) The second transition product is subjected to a third pyrolysis in an inert atmosphere to obtain an ozone oxidation catalyst.

2. The method for preparing an ozone oxidation catalyst according to claim 1, characterized in that: In the step (1), the dried sludge is subjected to a first pyrolysis in an inert atmosphere to obtain a third transition product, and the third transition product is washed with a dilute acid to obtain a first carbon powder.

3. The method for preparing an ozone oxidation catalyst according to claim 2, characterized in that: In the step (2), the mass ratio of the first carbon powder to the activator is 1:3 to 3:

1.

4. The method for preparing an ozone oxidation catalyst according to claim 3, characterized in that: In the step (4), the mass ratio of the second carbon powder to urea is 1:0.2-0.

6.

5. The method for preparing an ozone oxidation catalyst according to claim 4, characterized in that: In the step (5), the heating rate of the second transition product during the third pyrolysis in an inert atmosphere is controlled at 5-10° C. / min.

6. The method for preparing an ozone oxidation catalyst according to any one of claims 1 to 5, characterized in that: After step (5), the method includes step (6) of performing hydrophilic treatment on the ozone oxidation catalyst, wherein step (6) includes: 1) After mixing the ozone oxidation catalyst and a first binder, adding an appropriate amount of water to obtain a first paste, wherein the first binder is a water-soluble organic matter; 2) Using the first paste as a raw material to perform granulation operation to obtain first particles, and drying the first particles to obtain an ozone oxidation catalyst with a hydrophilic function.

7. The method for preparing an ozone oxidation catalyst according to any one of claims 1 to 5, characterized in that: After step (5), the method includes a step (7) of performing a hydrophobic treatment on the ozone oxidation catalyst, wherein the step (7) includes: 3) After mixing the ozone oxidation catalyst and the second binder, adding an appropriate amount of water to obtain a second paste, wherein the second binder is a hydrophobic organic substance; 4) Using the second paste as a raw material, a granulation operation is performed to obtain second particles, and the second particles are heat-treated to obtain an ozone oxidation catalyst having a hydrophobic function.

8. The method for preparing an ozone oxidation catalyst according to claim 6, characterized in that: The first binder is sodium carboxymethyl cellulose and / or sodium alginate.

9. The method for preparing an ozone oxidation catalyst according to claim 7, characterized in that: The second binder is a polytetrafluoroethylene solution.

10. The method for preparing an ozone oxidation catalyst according to claim 7, characterized in that: The heat treatment in the sub-step 4) includes two stages, the treatment temperature range of the first stage is 300-400°C, and the treatment temperature range of the second stage is 100-120°C.

11. The method for preparing an ozone oxidation catalyst according to any one of claims 1 to 5, characterized in that: The pyrolysis temperature ranges of the first pyrolysis, the second pyrolysis and the third pyrolysis are all 500-700°C.

12. The method for preparing an ozone oxidation catalyst according to any one of claims 2 to 5, characterized in that: The dilute acid includes dilute hydrochloric acid or dilute acetic acid.

13. The method for preparing an ozone oxidation catalyst according to any one of claims 1 to 5, characterized in that: The activator includes one or a mixture of two or more of KOH, Na2CO3, FeCl3, ZnCl2 and K2CO3.

14. A catalyst prepared by the method for preparing an ozone oxidation catalyst according to any one of claims 1 to 13.

15. A method for using a catalyst, comprising the following steps: The catalyst according to claim 14 is arranged in layers and stacked for use.

16. The method for using the catalyst according to claim 15, characterized in that: Several layers of catalysts with hydrophilic function are stacked on or below several layers of catalysts with hydrophobic function for use.

17. The method for using the catalyst according to claim 15, characterized in that: Catalysts with hydrophilic function and catalysts with hydrophobic function are arranged in layers and stacked for use.

18. The method for using the catalyst according to claim 17, characterized in that: The catalyst having a hydrophilic function has a different outer diameter from the catalyst having a hydrophobic function.

19. A method for treating wastewater using a wastewater treatment device, the wastewater treatment device comprising: A tower body and a processing unit arranged in the tower body, a water inlet is arranged at the upper part of the tower body, a water outlet is arranged at the lower part of the tower body, and the processing unit is located between the water inlet and the water outlet, wherein the processing unit includes: a floating valve tower plate, an air intake assembly and a catalytic tower plate loaded with the catalyst according to claim 14, the floating valve tower plate is located above the air intake assembly, and the catalytic tower plate is located below the air intake assembly.

20. The method for treating wastewater using a wastewater treatment device according to claim 19, characterized in that: The catalytic tower plate comprises a support plate on which the catalyst is loaded. The catalyst is used according to the method for using the catalyst according to any one of claims 15 to 18.

21. The method for treating wastewater using a wastewater treatment device according to claim 20, characterized in that: The catalytic tower plate comprises a first baffle, one side of which is connected to the support plate, and the value range of the angle α between the baffle and the support plate is: 0°<α≤90°.

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