Membrane pore aeration ozone heterogeneous catalytic reactor and water treatment system

Abstract

The invention discloses a membrane pore aeration ozone heterogeneous catalytic reactor and a water treatment system, and relates to the technical field of water treatment. The reactor comprises a reactor cavity, the top of the reactor cavity is provided with a water outlet assembly, and the bottom is provided with a water inlet assembly and a gas inlet assembly; the membrane component is arranged in the reactor cavity and comprises a bundle of hollow fiber membrane filaments which are bent in a U shape; the two ends of the hollow fiber membrane filaments are bundled and fixed in a mounting hard tube, the mounting hard tube is detachably connected with the air inlet assembly, and the air inlet assembly is used for communicating an external air supply device with the hollow fiber membrane filaments; micropores are distributed in the surfaces of the hollow fiber membrane filaments; and the reactor cavity is filled with catalyst particles. According to the membrane pore aeration ozone heterogeneous catalytic reactor provided by the invention, the ozone mass transfer efficiency and the utilization rate are improved, and the content of hydroxyl radicals used for degrading organic matters in water is increased, so that the organic matters which are difficult to degrade in water can be more effectively removed, and the ozone treatment operation cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and particularly to a membrane pore aeration ozone heterogeneous catalytic reactor and a water treatment system. Background Art

[0002] With the rapid development of urbanization and industrialization, the problem of water pollution has become increasingly prominent. Ozone oxidation is an efficient oxidation treatment method and is widely used in the removal of organic pollutants such as benzene compounds, phenolic compounds, polycyclic aromatic hydrocarbons, dyes, and antibiotics in wastewater, which pose great harm to human health and the environment. When using the catalytic ozone oxidation method to treat wastewater, the ozone contact reactor is the key; the common aeration methods in the reactor mainly include aeration disk aeration, ejector aeration, microporous aeration, surface or mechanical aeration, and ceramic membrane aeration, etc. However, the bubbles generated by these aeration methods are all millimeter-sized and above in diameter, and the bubbles rise rapidly in water and have a short residence time, resulting in low ozone mass transfer efficiency, short contact time with the catalyst, and small contact area, resulting in a low concentration of reactive oxygen species (ROS) in water, low ozone utilization rate, and increased system operation costs.

[0003] In contrast, bubbles with a diameter less than 50 μm are called micro-nano bubbles (MNBs). Compared with millimeter-sized bubbles, MNBs have a longer residence time in water, a larger specific surface area, higher mass transfer efficiency, and can generate more hydroxyl radicals (·OH), thereby strengthening the degradation of refractory organic compounds in water by ozone; the generation of micro-nano bubbles (MNBs) traditionally relies on dissolved air release and dispersed gas technologies, and these methods require pressurized mixing of gas and water during operation, and then release to form bubbles; however, equipment such as dissolved air pumps or high-pressure water pumps used in this method often significantly increases the construction and operation costs of the system. Summary of the Invention

[0004] Embodiments of the present invention provide a membrane pore aeration ozone heterogeneous catalytic reactor and a water treatment system, aiming to efficiently and low-costly utilize the ozone oxidation method to treat polluted water bodies.

[0005] The membrane pore aeration ozone heterogeneous catalytic reactor provided by the present invention includes:

[0006] A reactor cavity; an outlet assembly is provided at the top of the reactor cavity, and an inlet assembly and an air inlet assembly are provided at the bottom.

[0007] A membrane assembly, disposed in the reactor cavity, including a bundle of hollow fiber membrane filaments bent in a U shape; both ends of the hollow fiber membrane filaments are bundled and fixed in an installation hard tube, and the installation hard tube is detachably connected to the air inlet assembly, and the air inlet assembly is used to connect an external air supply device and the hollow fiber membrane filaments; micropores are arranged on the surface of the hollow fiber membrane filaments.

[0008] The reactor cavity is filled with catalyst particles.

[0009] Optionally, it further includes:

[0010] A first orifice plate disposed near the top position in the reactor cavity, the first orifice plate being located below the water outlet assembly; any one of the hollow fiber membrane filaments passes upward through a small hole of the first orifice plate and then passes downward through another small hole of the first orifice plate;

[0011] A second orifice plate disposed near the bottom position in the reactor cavity, the second orifice plate being located above the water inlet assembly and the air inlet assembly; the catalyst particles are stacked on the second orifice plate.

[0012] Optionally, the micropore diameter on the hollow fiber membrane filament is less than 100 nm.

[0013] Optionally, the material of the hollow fiber membrane filament is at least one of a mixed fiber ester microporous membrane, a nitrocellulose membrane, a polyvinylidene fluoride membrane, a cellulose acetate membrane, a regenerated cellulose membrane, a polyamide membrane, a polytetrafluoroethylene membrane, a polyvinyl chloride membrane, and a ceramic hollow fiber membrane.

[0014] Optionally, the particle size of the catalyst particles is 3 - 5 mm.

[0015] Optionally, the catalyst particles are at least one of an alumina-based catalyst, a transition metal oxide catalyst, and a carbon-based catalyst.

[0016] Optionally, the material of the catalyst particles is γ-Al 2 O 3 , MnO X / Al 2 O 3 , β-FeOOH / Al 2 O 3 , Cu-γ-Al 2 O 3 and at least one of them.

[0017] Among them, the γ-Al 2 O 3 is prepared by the following method: adding glucose and aluminum isopropoxide to pure water and fully mixing and reacting, adjusting the solution to a preset pH value using nitric acid, stirring for a period of time and then drying, grinding the dried product into small particles or powder, calcining at a preset temperature, and grinding the calcined product again to obtain γ-Al 2 O 3 powder;

[0018] The MnO X / Al2 O 3 、 β-FeOOH / Al 2 O 3 、 Cu-γ-Al 2 O 3 Any one of them is prepared using the γ-Al 2 O 3 as a carrier.

[0019] Optionally, the catalyst particles are prepared from catalyst powder, and the preparation steps include:

[0020] Adding the catalyst powder into a sodium alginate solution, stirring evenly and then dropping it into a calcium chloride solution with a preset concentration to obtain a mixed solution;

[0021] Refrigerating the mixed solution at a low temperature for a preset time, washing to remove the free calcium chloride on the surface and then drying to obtain the catalyst particles.

[0022] The water treatment system proposed by the present invention includes the above-mentioned membrane pore aeration ozone heterogeneous catalytic reactor, and:

[0023] A gas supply device, which is connected to the intake assembly of the membrane pore aeration ozone heterogeneous catalytic reactor and is used to provide ozone gas for the membrane pore aeration ozone heterogeneous catalytic reactor, including an oxygen gas source and an ozone generator;

[0024] A water supply device, including a water inlet pump; the water inlet pump is connected to the water inlet assembly of the membrane pore aeration ozone heterogeneous catalytic reactor and is used to pump the water to be treated into the membrane pore aeration ozone heterogeneous catalytic reactor.

[0025] Optionally, the water treatment system further includes:

[0026] A sampler, which is connected to the water outlet assembly of the membrane pore aeration ozone heterogeneous catalytic reactor and is used to sample the outlet water;

[0027] A tail gas destruction device, which is connected to the water outlet assembly of the membrane pore aeration ozone heterogeneous catalytic reactor and is used to treat the residual ozone in the outlet water

[0028] The present invention has the following beneficial effects:

[0029] The surface of the hollow fiber membrane has a large number of micropores, which can cut the introduced ozone gas and directly generate micro-nano level bubbles under appropriate pressure, increasing the contact area between the heterogeneous catalyst and the ozone gas, and at the same time making the polluted water contact more fully with the catalyst and ozone, improving the ozone mass transfer efficiency and utilization rate, and increasing the content of hydroxyl radicals used to degrade organic matter in water, so as to more effectively remove the refractory organic matter in water and reduce the operating cost of ozone treatment. Brief Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0031] Figure 1 It is a schematic diagram of the combined and disassembled structure of some embodiments of the membrane pore aeration ozone heterogeneous catalytic reactor of the present invention;

[0032] Figure 2 It is a schematic diagram of the device operation of some embodiments of the membrane pore aeration ozone heterogeneous catalytic reactor of the present invention;

[0033] Figure 3 It is a schematic diagram of the catalytic process in some embodiments of the membrane pore aeration ozone heterogeneous catalytic reactor of the present invention;

[0034] Figure 4 It is a schematic diagram of the process of the catalyst catalyzing ozone to generate hydroxyl radicals;

[0035] Figure 5 It is a structural block diagram of some embodiments of the water treatment system of the present invention;

[0036] Figure 6 It is a comparison experimental data graph of the membrane pore aeration ozone heterogeneous catalytic reactor of the present invention and the traditional aeration reactor;

[0037] Figure 7 It is a parallel experimental data graph of the catalyst catalysis of the present invention;

[0038] Figure 8 It is an experimental data graph of the ozone mass transfer efficiency of the present invention;

[0039] Figure 9 It is an image of the bubble distribution on the hollow fiber membrane in some embodiments of the membrane pore aeration ozone heterogeneous catalytic reactor of the present invention.

[0040] Explanation of the reference numerals in the drawings:

[0041] 1. Reactor cavity; 2. Effluent assembly; 3. Inlet assembly; 4. Inlet gas assembly; 4-1. Connector; 5. Membrane assembly; 6. Catalyst particles; 7-1. First orifice plate; 7-2. Second orifice plate; 100. Membrane pore aeration ozone heterogeneous catalytic reactor; 200. Oxygen gas source; 300. Ozone generator; 400. Feed water pump; 500. Sampler; 600. Tail gas destruction device. Detailed Embodiments

[0042] In order to make the object, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0043] Referring to Figure 1 , the membrane pore aeration ozone heterogeneous catalytic reactor provided by the embodiment of the present invention includes:

[0044] A reactor cavity 1; an outlet assembly 2 is provided at the top of the reactor cavity 1, and an inlet assembly 3 and an air inlet assembly 4 are provided at the bottom; a membrane assembly 5 is arranged in the reactor cavity 1, including a bundle of hollow fiber membrane filaments bent in a U shape; both ends of the hollow fiber membrane filaments are bundled and fixed in an installation hard tube, and the installation hard tube is detachably connected to the air inlet assembly 4, and the air inlet assembly 4 is used to connect an external gas supply device and the hollow fiber membrane filaments; micropores are arranged on the surface of the hollow fiber membrane filaments; catalyst particles 6 are filled in the reactor cavity 1.

[0045] Among them, the hollow fiber membrane is a highly selective separation medium that can separate according to differences in molecular size, shape, and properties, etc. It is mainly composed of many tiny hollow fiber membrane filaments, and these hollow fiber membrane filaments are arranged in a network shape in the entire membrane assembly, having a large aeration surface area and good gas-liquid mass transfer performance.

[0046] The material of the hollow fiber membrane filaments includes, but is not limited to, mixed fiber ester microporous filter membranes, nitrocellulose filter membranes, polyvinylidene fluoride filter membranes, cellulose acetate filter membranes, regenerated cellulose filter membranes, polyamide filter membranes, polytetrafluoroethylene filter membranes, polyvinyl chloride filter membranes, ceramic hollow fiber membranes, etc.

[0047] Preferably, the pore diameter of the micropores on the hollow fiber membrane filaments is less than 100 nm to optimize the bubble generation efficiency.

[0048] Among them, the catalyst particles are solid particles to form heterogeneous catalysis; heterogeneous catalysis refers to a chemical reaction process in which the catalyst and the reactants are in different phases (such as a solid catalyst and a gas or liquid reactant). Compared with homogeneous catalysts, it has the advantages of not easily causing secondary pollution, easy catalyst recovery, low cost, and good effect. Preferably, the particle size of the catalyst particles is 3-5 mm, which is convenient for filling into the reactor cavity and has appropriate particle gaps to optimize the effect of heterogeneous catalytic ozone oxidation.

[0049] In some embodiments, the material of the reactor cavity 1 includes, but is not limited to, glass, stainless steel, fiberglass, plexiglass, polytetrafluoroethylene, etc.

[0050] In some embodiments, the intake assembly 4 is disposed directly below the reactor cavity 1, the water inlet assembly 3 is disposed on the side of the lower end of the reactor cavity 1, and the water outlet assembly 2 is disposed directly above the reactor cavity 1; the reactor cavity 1 is threadedly connected to each assembly.

[0051] In some embodiments, stainless steel valves are provided at the inlets and outlets of each assembly, and a PTFE (polytetrafluoroethylene) soft pad can be provided between the reactor cavity 1 and each assembly for sealing.

[0052] In some embodiments, a small section of hard tube made of PTFE can be selected as the installation hard tube (not shown in the figure). Both ends of the hollow fiber membrane filaments can be bonded in the PTFE hard tube through ozone-resistant glue to form the membrane assembly 5, and the PTFE hard tube is connected to the intake assembly 4 through a quick connector 4-1 made of stainless steel.

[0053] Refer to Figure 2 , in the embodiment of the present invention, the polluted water to be treated enters from the water inlet on the side of the lower end of the reactor, and the ozone gas enters from the gas inlet at the bottom of the reactor, and is uniformly and controllably released into the reactor through the membrane pores on the hollow fiber membrane to contact and react with the catalyst (refer to Figure 3 ), and the treated water is discharged from the water outlet at the top of the reactor.

[0054] In the embodiment of the present invention, the surface of the hollow fiber membrane has a large number of micropores, which can cut the introduced ozone gas, and micro-nano level bubbles can be directly generated under appropriate pressure, increasing the contact area between the heterogeneous catalyst and the ozone gas, and at the same time enabling the polluted water to contact the catalyst and ozone more fully, improving the ozone mass transfer efficiency and utilization rate, increasing the content of hydroxyl radicals used to degrade organic matter in water, so as to more effectively remove the refractory organic matter in water and reduce the operating cost of ozone treatment.

[0055] In the embodiment of the present invention, the mechanism of removing organic pollutants by heterogeneous catalysis combined with ozone oxidation includes two forms: direct ozone oxidation and indirect ozone oxidation.

[0056] Among them, direct ozone oxidation means that the catalyst can improve the mass transfer and decomposition rate of ozone in the liquid phase, and at the same time, the adsorption process on its huge specific surface increases the collision probability between ozone and organic matter, improving the reaction rate. Direct ozone oxidation can be represented by the following reaction formula:

[0057]

[0058]

[0059] In the formula, H-X represents an organic pollutant, X -It represents that under alkaline conditions, organic pollutants undergo ionization reactions and carry negative charges; ozone is an electrophilic reagent and is prone to degrade negatively charged organic pollutants.

[0060] Ozone indirect oxidation means that the catalyst can accelerate the decomposition of ozone to generate active substances and improve the degradation rate of organic pollutants. The key to ozone indirect oxidation is the decomposition of ozone on the catalyst surface. Taking metal oxide catalysts as an example, ozone forms different intermediates on the surfaces of n-type and p-type oxides, and then initiates free radical reactions. The reaction process can be expressed by the following formula:

[0061]

[0062]

[0063]

[0064]

[0065] In the formula, M represents a metal element. Ozone decomposes on the metal oxide surface to generate surface-bound oxygen atoms (n-type) and ionic intermediates with semi-peroxide and semi-superoxide characteristics (p-type), and finally generates active substances - hydroxyl radicals through a series of free radical reactions.

[0066] Refer to Figure 4 , the process of ozone heterogeneous catalytic oxidation releasing hydroxyl radicals includes: ozone dissolved in water reacts with surface hydroxyl groups on the catalyst surface to generate hydroperoxide radicals and oxygen. The hydroperoxide radicals then react with ozone to generate hydroperoxyl radicals. The hydroperoxyl radicals further decompose into hydroxyl radicals and superoxide anions. The superoxide anions then react with ozone in water to generate superoxide radicals and oxygen, which are released on the catalyst surface, forming holes. The holes and water regenerate surface hydroxyl groups to enter the next cycle. The active center on the catalyst surface is the surface hydroxyl group, which shows as B acid sites; due to the existence of unsaturated sites, water molecules undergo ion exchange reactions on the catalyst surface, generating surface coordination effects and hydrolyzing to form surface hydroxyl groups, showing strong catalytic activity.

[0067] Based on the above embodiments, further, refer to Figure 1 , in some embodiments, the membrane pore aeration ozone heterogeneous catalytic reactor further includes:

[0068] A first orifice plate 7-1 disposed near the top position in the reactor cavity 1, and the first orifice plate 7-1 is located below the water outlet assembly 2; any hollow fiber membrane filament passes upward through a small hole of the first orifice plate 7-1 and then downward through another small hole of the first orifice plate 7-1, so that the hollow fiber membrane filament is bent in a U shape and is evenly distributed in the reactor cavity 1 through the limitation of the first orifice plate 7-1.

[0069] A second orifice plate 7 - 2 is disposed near the bottom of the reactor chamber. The second orifice plate 7 - 2 is located above the water inlet assembly 3 and the air inlet assembly 4 . Catalyst particles 6 are stacked on the second orifice plate 7 - 2 .

[0070] The structures of the first orifice plate 7-1 and the second orifice plate 7-2 are shown in Figure 1 As shown in the partial enlarged figure A, there are a number of evenly distributed small holes, the pore size of which is larger than the diameter of the hollow fiber membrane and smaller than the diameter of the catalyst particles.

[0071] In some embodiments, the inner wall of the reactor chamber 1 is provided with protrusions for accommodating the first orifice plate 7 - 1 and the second orifice plate 7 - 2 , respectively.

[0072] The catalyst particles that can be used in the embodiments of the present invention include but are not limited to aluminum oxide-based catalysts, transition metal oxide catalysts and carbon-based catalysts, such as MnO 2 、TiO 2 , Fe 2 O 3 ,CuO,Co 3 O 4 Transition metal oxide catalysts, activated carbon, carbon nanotubes and other carbon-based catalysts, and some multi-metal oxide catalysts with catalytic ozone degradation properties, rare earth modified oxide catalysts, etc. can also be used; the catalyst can form particles independently, or it can be loaded on some materials with microporous and mesoporous structures (such as silicon aluminum matrix, diatomaceous earth, microporous molecular sieve, etc.) to form a supported catalyst.

[0073] In some embodiments, the material of the catalyst particles includes but is not limited to γ-Al 2 O 3 、MnO X / Al 2 O 3 ,β-FeOOH / Al 2 O 3 、Cu-γ-Al 2 O 3 etc., γ-Al 2 O 3 It is an activated alumina with a well-developed microporous and mesoporous structure, which can provide a large number of active sites for catalytic reactions.

[0074] Among them, the γ-Al used in the embodiment of the present invention 2 O 3 It can be synthesized by template method: glucose and aluminum isopropoxide are added to pure water and mixed thoroughly for reaction, nitric acid is used to adjust the solution to a preset pH value, and the solution is dried after stirring for a period of time. The dried product is ground into small particles or powder, and calcined at a preset temperature. The calcined product is then ground into powder to obtain γ-Al2 O 3 powder.

[0075] Specifically, in one embodiment, 18 g of glucose and 21 g of aluminum isopropoxide are weighed and added to 270 ml of pure water for full mixing and reaction. A magnetic stirrer is used to stir at a rate of 500 rpm for 12 h; nitric acid with a concentration of 50% is used to adjust the pH of the solution to 5, and stirring is continued for 6 h; it is placed in an oven and dried at 100 °C; taken out and ground into small particles or powder, put into a ceramic boat, and placed in a muffle furnace to be calcined at 600 °C for 6 h at a heating rate of 5 °C / min; the obtained material is taken out and ground into powder with a mortar to obtain γ-Al 2 O 3 powder.

[0076] Using γ-Al 2 O 3 as the catalyst carrier, MnO can be prepared by the impregnation method X / Al 2 O 3 : Dissolve manganese acetate in water, add γ-Al 2 O 3 , then dry it, calcine it at a preset temperature, and grind the calcined product to obtain MnO X / Al 2 O 3 powder.

[0077] Specifically, in one embodiment, 0.2619 g of manganese acetate is dissolved in 10 ml of water, then 1.5 g of γ-Al 2 O 3 is added, dried at 100 °C, and then calcined in a muffle furnace at a heating rate of 5 °C / min at 450 °C for 3 h. The obtained material is ground to obtain MnO X / Al 2 O 3 powder.

[0078] Using γ-Al 2 O 3 as the catalyst carrier, β-FeOOH / Al can be prepared by the hydrothermal synthesis method 2 O 3 : Dissolve ferric chloride hexahydrate and urea in water, then add γ-Al 2 O 3 , adjust to the preset pH value with hydrochloric acid, then heat in a water bath for the preset time, and finally cool to room temperature. After washing and drying, grind to obtain β-FeOOH / Al 2 O 3 powder.

[0079] Specifically, in one embodiment, 0.3 g of ferric chloride hexahydrate and 0.4 g of urea are weighed and dissolved in 30 ml of water, and then 2 g of γ-Al 2 O 3 is added. The pH is adjusted to 1.6 with hydrochloric acid, and then heated in a water bath at 100 °C for 4 h. Finally, after cooling to room temperature, it is rinsed with water and air-dried at room temperature. The material is ground to obtain β-FeOOH / Al 2 O 3 powder.

[0080] Cu-γ-Al 2 O 3 can be prepared by the following method: γ-Al 2 O 3 and copper nitrate trihydrate are added to pure water and stirred evenly, then added to a reflux device, and kept at a preset temperature for a preset time under constant reflux. The cooled solution is filtered and washed, and the filter cake is taken out and air-dried, and then dried at a constant temperature. Finally, it is calcined at a preset temperature, and the calcined product is ground to obtain Cu-γ-Al 2 O 3 powder.

[0081] Specifically, in one embodiment, 5 g of γ-Al 2 O 3 and 0.5 g of copper nitrate trihydrate are placed in a 100 ml beaker, 50 ml of pure water is added, and after stirring evenly, it is poured into a 250 ml round-bottom flask using a glass rod for drainage. The reflux device is assembled, and it is kept at a constant temperature of 200 °C under reflux at a stirring rate of 500 rpm for 4 h using a magnetic stirrer. After completion, the solution is poured into a small beaker, and after cooling, it is filtered and washed three times using a Buchner funnel; the filter cake is taken out and air-dried in a ventilated place, and then placed in a vacuum drying oven and dried at a constant temperature of 120 °C for 2 h; then it is put into a muffle furnace and calcined at 700 °C for 5 h, and after cooling, it is taken out and the material is ground to obtain Cu-γ-Al 2 O 3 powder.

[0082] The heterogeneous catalysts prepared by the above preparation method are all in powder form, and they still need to be prepared into catalyst particles with a particle size of about 3-5 mm. The preparation steps include:

[0083] Adding the catalyst powder into the sodium alginate solution, stirring evenly and then dropping it into the calcium chloride solution with a preset concentration to obtain a mixed solution; refrigerating the mixed solution at a low temperature for a preset time, washing to remove the free calcium chloride on the surface, and then drying to obtain the catalyst particles.

[0084] Specifically, in one embodiment, 1.5 g of sodium alginate was weighed and added to 46.5 ml of pure water, and the mixture was heated in a water bath at 60 °C with constant stirring for 2 h; then 2 g of the above-mentioned catalyst powder was weighed and added to the sodium alginate solution, and stirring was continued for 2 h; after the catalyst powder was uniformly stirred in the system, a syringe was used to drop the mixed solution of the catalyst and sodium alginate into 100 ml of 10% calcium chloride solution; after the dropping was completed, the mixed solution was refrigerated at 4 °C for 24 h; the catalyst was taken out and washed with a large amount of deionized water to remove the free calcium chloride on the surface of the catalyst, and then the catalyst was put into an oven and dried at 75 °C for 4 h to obtain the corresponding catalyst particles.

[0085] It should be noted that based on the different requirements for ozone treatment of polluted water bodies, in some other embodiments, the catalyst particles can be replaced with substances having adsorption characteristics such as activated carbon for water purification; in some other embodiments, the reactor cavity can also be divided into multiple segments by axially arranging multiple orifice plates in the reactor cavity, and different segments are loaded with different catalyst particles or adsorption particles to achieve segmented treatment of polluted water bodies.

[0086] Based on the membrane pore aeration ozone heterogeneous catalytic reactor provided in the above embodiments, the present invention also proposes a water treatment system.

[0087] Refer to Figure 5 , the water treatment system includes a membrane pore aeration ozone heterogeneous catalytic reactor 100; a gas supply device, which is connected to the intake assembly of the membrane pore aeration ozone heterogeneous catalytic reactor 100, and includes an oxygen gas source 200 and an ozone generator 300; a water supply device, which includes a water inlet pump 400; the water inlet pump 400 is connected to the water inlet assembly of the membrane pore aeration ozone heterogeneous catalytic reactor 100 for pumping the water to be treated into the membrane pore aeration ozone heterogeneous catalytic reactor 100.

[0088] In some embodiments, the water treatment system proposed by the present invention further includes: a sampler 500, which is connected to the water outlet assembly of the membrane pore aeration ozone heterogeneous catalytic reactor 100 for sampling the water discharged from the device; a tail gas destruction device 600, which is connected to the water outlet assembly of the membrane pore aeration ozone heterogeneous catalytic reactor 100 for treating the residual ozone in the water discharged from the device.

[0089] In order to more specifically illustrate the technical effects that can be achieved by the present invention, the following parallel control group experiments were also carried out by the present invention.

[0090] The target water body pollutant was selected as deethylatrazine (DEA). DEA has the characteristic of only reacting with hydroxyl radicals and not with ozone in the system of the present invention. Therefore, DEA was used as an indicator of hydroxyl radicals for the experiment (in some other experimental methods, organic substances such as nitrobenzene and phenol that react rapidly with hydroxyl radicals but hardly react with ozone can also be used to replace DEA).

[0091] First, a comparison is made between the membrane pore aeration ozone heterogeneous catalytic reactor provided by the embodiments of the present invention and the traditional aeration reactor. Experimental groups are set up: Experimental group 1 - a membrane pore aeration system without adding a catalyst, Experimental group 2 - a membrane pore aeration system with added catalyst; Control groups: Control group 1 - a traditional aeration system without adding a catalyst, Control group 2 - a traditional aeration system with added catalyst; In this experiment, γ-Al 2 O 3 catalyst particles are selected as the catalyst.

[0092] Among them, the traditional aeration reactor used in the control group is obtained by replacing the membrane module in the membrane pore aeration ozone heterogeneous catalytic reactor provided by the embodiments of the present invention with a common aeration head on the market.

[0093] The specific experimental conditions are as follows: the pH of the water to be treated is 7, the DEA concentration is 10 μM, the ozone concentration in the reactor is 50 μM, the ozone flow rate is 2 g / min, and the catalyst concentration in the system is 280 g / L. Experiments are carried out with different residence times (5 min, 10 min, 20 min, 30 min).

[0094] The specific experimental process is as follows: First, pure water and ozone are introduced into the reactor. After the equipment runs stably, the outlet ozone concentration is adjusted to 50 μM; a DEA solution with a pH of 7 and a concentration of 10 μM is introduced into the device. After the corresponding residence time, a sodium sulfite solution is added to terminate the reaction at this time, and the ozone concentration at this time is measured.

[0095] The experimental results are as Figure 6 shown, Figure 6 including (a) a columnar comparison chart of the degradation of DEA by two aeration methods (membrane pore aeration, conventional aeration) without adding a catalyst. The abscissa is the residence time, and the ordinate C t / C 0 represents the DEA residual rate; (b) a columnar comparison chart of the degradation of DEA by two aeration methods when adding self-made γ-Al 2 O 3 catalyst particles; (c) a columnar comparison chart of the RCT values of two aeration methods when adding self-made γ-Al 2 O 3 catalyst particles.

[0096] Among them, the RCT value is used to quantify the hydroxyl radical (·OH) and ozone (O 3The generation ratio of (...) The RCT value is defined as the ratio of the hydroxyl radical exposure to the ozone exposure, which is usually used to evaluate the concentration of hydroxyl radicals generated by ozone decomposition and to model the removal of organic pollutants. The calculation method of the RCT value is shown in the following formula:

[0097]

[0098] In the formula, represents the indirect characterization of the hydroxyl radical yield, represents the initial concentration of DEA, represents the real-time concentration of DEA, represents the second-order reaction rate constant of hydroxyl radicals and DEA, represents the integral of the ozone concentration decay curve over time.

[0099] It can be seen from the experimental results that whether it is ozone treatment alone or ozone treatment with the addition of a catalyst, the membrane pore aeration effect is better than that of traditional aeration, and there are more hydroxyl radicals in the membrane pore aeration system for degrading organic matter.

[0100] Then, parallel experiments on catalyst catalysis were carried out on the membrane pore aeration ozone heterogeneous catalytic reactor provided in the embodiments of the present invention to explore the treatment efficiency of the device; three experimental groups were set up in this experiment, namely ozone treatment alone, addition of alumina gel particles and addition of alumina active particles, and experiments with different residence times (5 min, 10 min, 20 min, 30 min) were carried out.

[0101] The specific experimental process is as follows: First, pure water and ozone are introduced into the reactor. After the equipment runs stably, the ozone concentration of the effluent is adjusted to 50 μM; a DEA solution with a pH of 7 and a concentration of 10 μM is introduced into the device. After a corresponding residence time, a sample is taken and sodium sulfite solution is added to terminate the reaction at this time, and the ozone concentration at this time is measured.

[0102] The experimental results are as Figure 7 shown, Figure 7 including (a) a columnar comparison chart of the DEA removal effects of different experimental groups; (b) a columnar comparison chart of the RCT values of different experimental groups.

[0103] It can be seen from the experimental results that the addition of the two catalysts significantly improves the treatment effect compared with ozone treatment alone. Among them, when the residence time is 30 min, the active alumina particles almost completely remove DEA; at each selected residence time, the RCT values of the experimental groups adding alumina gel particles and adding alumina active particles are significantly greater than those of the experimental group with ozone treatment alone; thus, it can be seen that for the membrane pore aeration ozone heterogeneous catalytic reactor provided in the embodiments of the present invention, the presence of the heterogeneous catalyst has a great promoting effect on increasing the content of hydroxyl radicals in water during the ozone oxidation treatment process.

[0104] After that, ozone mass transfer efficiency experiments were also carried out on two aeration methods: traditional aeration and membrane pore aeration.

[0105] The specific experimental process is as follows: Pure water and ozone were respectively introduced into the traditional aeration reactor and the membrane pore aeration reactor provided in the embodiment of the present invention. The ozone flow rate was controlled at 2 g / min, and samples were taken every 1 min to measure the ozone concentration at this time.

[0106] The experimental results are as Figure 8 shown. It can be seen from the experimental results that under the same conditions and within the same time, the ozone concentration in the membrane pore aeration system is higher than that in the traditional aeration, that is, the ozone mass transfer efficiency is higher. This is because the bubbles in the membrane pore aeration are micro-nano bubbles, which can increase the residence time of ozone in water.

[0107] At the same time, the surface of the hollow fiber membrane has a more uniform bubble distribution (see Figure 9 ), which can make the organic matter and catalyst in water contact more fully, improve the ozone utilization rate, and reduce the system operation cost.

[0108] It can be seen from the above embodiments that the present invention provides a water treatment reactor capable of manufacturing ozone micro-nano bubbles at a lower cost in view of the problems of low ozone utilization rate, short contact time with the catalyst, and high cost of generating micro-nano bubbles in the current traditional aeration method. Combined with ozone heterogeneous catalytic oxidation, taking advantage of the characteristics of micro-nano bubbles with high internal pressure and large specific surface area, it increases the contact time between ozone micro-nano bubbles and the catalyst, improves the ozone mass transfer efficiency, and generates more hydroxyl radicals at the same time to enhance the treatment efficiency of ozone for removing refractory organic matter in water, which is of great significance for the purification and protection of water resources.

[0109] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A membrane aeration ozone heterogeneous catalytic reactor, characterized in that: include: Reactor cavity; the top of the reactor cavity is provided with a water outlet assembly, and the bottom is provided with a water inlet assembly and an air inlet assembly; A membrane assembly is arranged in the reactor cavity, comprising a bundle of hollow fiber membrane filaments bent in a U-shape; the two ends of the hollow fiber membrane filaments are bundled and fixed in a mounting hard pipe, the mounting hard pipe is detachably connected to the air intake assembly, and the air intake assembly is used to connect an external air supply device and the hollow fiber membrane filaments; the surface of the hollow fiber membrane filaments is provided with micropores; The reactor cavity is filled with catalyst particles.

2. The membrane pore aeration ozone heterogeneous catalytic reactor according to claim 1, characterized in that: Also includes: A first orifice plate disposed in the reactor chamber near the top, wherein the first orifice plate is located below the water outlet assembly; Any of the hollow fiber membranes passes upward through a small hole of the first orifice plate, and then passes downward through another small hole of the first orifice plate; A second orifice plate is arranged near the bottom of the reactor cavity, and the second orifice plate is located above the water inlet assembly and the air inlet assembly; the catalyst particles are piled on the second orifice plate.

3. The membrane pore aeration ozone heterogeneous catalytic reactor according to claim 1, characterized in that: The micropore diameter of the hollow fiber membrane is less than 100 nm.

4. The membrane pore aeration ozone heterogeneous catalytic reactor according to claim 1, characterized in that: The hollow fiber membrane is made of at least one of a mixed fiber ester microporous filter membrane, a cellulose nitrate filter membrane, a polyvinylidene fluoride filter membrane, a cellulose acetate filter membrane, a regenerated cellulose filter membrane, a polyamide filter membrane, a polytetrafluoroethylene filter membrane, a polyvinyl chloride filter membrane, and a ceramic hollow fiber membrane.

5. The membrane aeration ozone heterogeneous catalytic reactor according to claim 1, characterized in that: The particle size of the catalyst particles is 3-5 mm.

6. The membrane pore aeration ozone heterogeneous catalytic reactor according to claim 5, characterized in that: The catalyst particles are at least one of an alumina-based catalyst, a transition metal oxide catalyst, and a carbon-based catalyst.

7. The membrane aeration ozone heterogeneous catalytic reactor according to claim 5, characterized in that: The catalyst particles are γ-Al2O3, MnO X / Al2O3, β-FeOOH / Al2O3, Cu-γ-Al2O3; The γ-Al2O3 is prepared by the following method: adding glucose and aluminum isopropoxide to pure water and mixing them thoroughly for reaction, adjusting the solution to a preset pH value using nitric acid, drying after stirring for a period of time, grinding the dried product into small particles or powder, calcining at a preset temperature, and grinding the calcined product to obtain γ-Al2O3 powder; The MnO X Any one of / Al2O3, β-FeOOH / Al2O3, and Cu-γ-Al2O3 is prepared using the γ-Al2O3 as a carrier.

8. The membrane aeration ozone heterogeneous catalytic reactor according to claim 7, characterized in that: The catalyst particles are prepared from catalyst powder, and the preparation steps include: Add the catalyst powder to the sodium alginate solution, stir evenly, and then dropwise add to a calcium chloride solution of a preset concentration to obtain a mixed solution; The mixed solution is refrigerated at low temperature for a preset time, washed to remove free calcium chloride on the surface, and then dried to obtain the catalyst particles.

9. A water treatment system, characterized in that: The invention comprises the membrane aeration ozone heterogeneous catalytic reactor according to any one of claims 1 to 8, and: A gas supply device, connected to the air inlet assembly of the membrane pore aeration ozone heterogeneous catalytic reactor, for providing ozone gas to the membrane pore aeration ozone heterogeneous catalytic reactor, including an oxygen gas source and an ozone generator; The water supply device comprises a water inlet pump; the water inlet pump is connected to the water inlet component of the membrane pore aeration ozone heterogeneous catalytic reactor and is used to pump the water to be treated into the membrane pore aeration ozone heterogeneous catalytic reactor.

10. The water treatment system according to claim 9, characterized in that: Also includes: A sampler, connected to the water outlet component of the membrane pore aeration ozone heterogeneous catalytic reactor, for sampling the water outlet of the device; The tail gas destruction device is connected to the water outlet component of the membrane pore aeration ozone heterogeneous catalytic reactor and is used for treating the residual ozone in the water outlet of the device.

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