Wet-type air catalytic oxidation method for wastewater COD (Chemical Oxygen Demand) degradation

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a wet-type air catalytic oxidation method for wastewater COD (Chemical Oxygen Demand) degradation, which comprises the following steps: loading CuO < 1-x > on a dealuminated natural mordenite molecular sieve to obtain CuO < 1-x > / DM, and carrying out catalytic oxidation degradation on COD wastewater by using the CuO < 1-x > / DM as a catalyst and a wet-type air method, wherein the structure of CuO1-x can be regarded as copper oxide doped with cuprous oxide, after oxygen vacancies (cuprous oxide is doped) are introduced into copper oxide crystals which do not have oxidation catalytic activity originally, the catalytic performance of the copper oxide crystals on organic matters is activated, CuO1-x / DM serving as a catalyst not only improves the degradation rate of COD wastewater, but also can be recycled, and therefore, the CuO1-x / DM can be recycled. The invention provides a pollution-free, energy-consumption-free, economic and environment-friendly method for wet-type air oxidation of COD (Chemical Oxygen Demand) wastewater.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a wet air catalytic oxidation method for degrading COD in wastewater. Background Art

[0002] Organic wastewater consumes dissolved oxygen in water, which is one of the main factors causing stench and even suffocating aquatic plants and animals. Therefore, organic wastewater is also called chemical oxygen demand (COD) wastewater. At present, there are mainly biodegradation, aeration, chemical flocculation and wet air oxidation (WAO) to remove COD. Among them, the oxidant of WAO can be taken from the atmosphere, so the cost is low, and the treatment method is carried out according to the chain free radical oxidation reaction, which is very promising in treating the difficult-to-degrade organic matter in organic wastewater.

[0003] CN117964172A discloses a method for treating high-concentration organic wastewater by a hydrogen peroxide coordinated catalytic wet air oxidation method. The method for treating high-concentration organic wastewater by a hydrogen peroxide coordinated catalytic wet air oxidation method comprises the following steps: S1, pretreatment: according to the quality of the wastewater, the high-concentration organic wastewater is pretreated initially to remove particulate matter, suspended matter and colloidal matter in the wastewater; S2, advanced oxidation: the wastewater filtered and impurity-removed in step S1 is added with reagents to adjust the pH value to 2-5, and then heat-exchanged with the advanced oxidation effluent, and then heated for a second time by adding steam, and then sent to an advanced oxidation device containing a catalyst, and oxygen / hydrogen peroxide are coordinated to carry out catalytic oxidation reaction at 130-200°C for 10-30 minutes; S3, biochemical treatment: the pH of the wastewater after advanced oxidation is adjusted to neutral, and gas-liquid separation is carried out, and the liquid is cooled by circulating water after heat exchange with the advanced oxidation inlet water, and then sent to the biochemical reaction unit to further remove organic pollutants in the wastewater. The method simultaneously adds hydrogen peroxide and oxygen as oxidants to improve the efficiency of the wet oxidation reaction of wastewater.

[0004] CN107344773B discloses a liquid membrane catalytic oxidation process method suitable for wastewater upgrading and transformation projects, which is applied to wastewater upgrading and transformation projects in chemical parks, and comprises the following steps: the first step is to allow chemical wastewater to enter the secondary sedimentation tank and effluent, and separate the biochemical sludge and effluent in the chemical wastewater; the second step is to sort the pollutants in the chemical wastewater to be treated, determine the priority of the pollutants, and establish a priority stack, and push the pollutants into the priority stack. The pollutants with high priority are first popped out of the priority stack. The priority is determined according to the degree of harm of the pollutants. The higher the degree of harm, the higher the priority. The primary liquid membrane degradation process pool and the secondary liquid membrane degradation process pool are placed in the priority stack. The decomposition process pool is divided into a plurality of small degradation process pools, and all the small degradation process pools are numbered and connected in series. The smaller the number, the earlier the serial position. A liquid membrane is set in the small degradation process pool. Different irreversible reaction reagents are added to the inner phase of the liquid membrane according to different pollutants, so as to achieve the purpose of retaining the pollutants in the inner phase when the pollutants react with the irreversible reaction reagents to convert them into substances that cannot penetrate the liquid membrane. The pollutants are ejected from the priority stack in sequence, and the inner phase of the liquid membrane in the small degradation process pool is designed in ascending order according to the ejected pollutants in the order of numbers; a booster pump is used to pump the pollutants after the first step of treatment into the liquid membrane. The chemical wastewater is pumped into the core filter to remove the suspended solids therein, and the pressure at the inlet of the core filter is tested. The test adopts a periodic test method with a period of T, where the unit of T is seconds, and the allowable pressure range is P±ΔP, where P is the required reference pressure set, and ΔP is the allowable error pressure difference. An error buzzer system is set, and when the pressure range is exceeded, an error is immediately reported; ensuring that the chemical wastewater treated in the first step can be delivered to the core filter in a timely manner and at a certain flow rate, and then using a high-pressure plunger pump to make the filtered chemical wastewater flow in parallel upward, and adding multiple shock absorbers in the flow path in the parallel upward direction to absorb excessive pressure, and then entering the The pollutants are removed from the first-level liquid film degradation process pool and the small degradation process pools connected in series in the second-level liquid film degradation process pool, and the flow routes of the pollutants are simulated and the key time points of the flow are recorded. The simulated flow routes of the pollutants are represented by position automata. The states in the position automata are the positions of the pollutants and the solutes in the chemical wastewater in the small degradation process pools, which are divided into three types: external phase, internal phase, and feed liquid. The feed liquid is the chemical wastewater treated in the first step. The transition between the states occurs due to the change in the position of the pollutants, and the time when the position of the pollutants changes is marked on the transition;The third step is to carry out n oxidation reactions, which are summarized as an oxidation process. In the oxidation process, the path through which the chemical wastewater treated in the second step passes adopts a baffle tube, and the baffle tube is used to allow the oxidant of the corresponding oxidation reaction to be better dissolved therein, thereby oxidizing and decomposing the pollutants in the chemical wastewater treated in the second step; the oxidation reaction is any one of a wet oxidation reaction, a photochemical oxidation technology, a supercritical water oxidation technology, and an electrochemical oxidation technology, and the n oxidation reactions are n catalytic oxidation reactions, which are set to be the same catalytic oxidation reaction, and n is an integer greater than or equal to 0; in the n oxidation reactions, a combination of oxidation reactions is carried out in coordination, that is, on the basis of the oxidation reaction, the reaction is carried out in combination with an environmental treatment technology; the environmental treatment technology includes an active Carbon, ultrasound, microwave, strong oxidant; the combination of the oxidation reaction and the environmental treatment technology is not an arbitrary combination, but must be based on feasibility, that is, a feasible combination of the oxidation reaction is set in advance, and all the oxidation reactions and environmental treatment technologies are represented, and Ni and Mj are used to represent them respectively, that is, Ni represents the oxidation reaction, Mj represents the environmental treatment technology, i is the specific number of the oxidation reaction, j is the specific number of the environmental treatment technology, which is a positive integer, N represents all the oxidation reactions, M represents all the environmental treatment technologies, and the feasible combination is a pre-set combination containing one Ni and one Mj; the fourth step is to enter the sedimentation tank to separate the chemical wastewater that has undergone the catalytic oxidation reaction in the third step. Sludge and effluent; in the process from the second step to the fourth step, the indicators in the chemical sewage in each step are detected by the sewage control detection system, the indicator is an indicator table, including various assessment indicators of the chemical sewage, each of the assessment indicators includes a global indicator variable and three local indicator variables, and, for each step of the process, a global time variable and a local time variable are set, the global time variable is the time from the start of recording the detection of the indicator, and changes with the global clock, the global clock starts with the time from the start of recording the detection of the indicator, and takes the set time unit as the specific measurement unit of time change, the set time unit is any integer multiple of seconds, and starts recording the The time spent in the liquid membrane catalytic oxidation process, the local time variable starts with the start time of each step of the process, changes with the local clock, the local clock takes the set time unit as the specific measurement unit of time change, and starts to record the time spent in each step of the process; the global indicator variable records various assessment indicators of the chemical wastewater during the process from the second step to the fourth step, accompanied by the change of the global time variable, and may be updated during the process from the second step to the fourth step; the local indicator variable records various assessment indicators of the chemical wastewater at the beginning of each step from the second step to the fourth step, accompanied by the change of the local indicator variable, and may be updated after each step of the process. ;

[0005] In the prior art, the key factor of wet air oxidation technology is strong oxidizing free radicals, so highly active free radicals are needed to induce diradical oxygen to enter the reaction. Currently, the commonly used catalysts are H 2 O 2 / O 2 Catalyst, H 2 O 2 / O 2 The catalyst can treat wastewater with high COD value and chromaticity, with COD removal rate up to 80% and chromaticity removal rate higher than 90%. 2 O 2 / O 2 The catalyst consumes a large amount of peroxide, the catalyst cannot be recycled and reused, and the reaction products cannot be completely degraded into carbon dioxide and water, so the expected industrial effect cannot be achieved. Summary of the invention

[0006] After long-term production practice, it is found that wet air oxidation method for treating COD wastewater requires highly active free radicals to induce diradical oxygen to enter the reaction. The commonly used catalysts are H 2 O 2 / O 2 Catalyst, H 2 O 2 / O 2 The catalyst can treat wastewater with high COD value and chromaticity, with COD removal rate up to 80% and chromaticity removal rate higher than 90%. 2 O 2 / O 2 The catalyst will consume a large amount of peroxide, the catalyst cannot be recycled and reused, and the reaction products cannot be completely degraded into carbon dioxide and water, so the expected industrial effect cannot be achieved.

[0007] In view of this, the present invention discloses a wet air catalytic oxidation method for degrading COD of wastewater.

[0008] In one embodiment, the wet air catalytic oxidation method for wastewater COD degradation disclosed in the present invention comprises:

[0009] Step S1, CuO 1-x CuO attached to dealuminated natural mordenite molecular sieve 1-x / DM catalyst;

[0010] Step S2, the CuO 1-x / DM catalyst is put into wastewater, air is introduced into the wastewater by using an air pump until the air concentration in the wastewater reaches saturation, and then the introduction of air is stopped, and the CuO1-x / DM catalyst and wastewater are subjected to catalytic oxidation reaction at a constant temperature.

[0011] In one embodiment, in step S1, CuO is configured 1-x The method of / DM catalyst comprises the following steps:

[0012] Step S11, grinding and crushing the blocky natural mordenite and then sieving to obtain natural mordenite powder;

[0013] Step S12, adding a dealuminizing agent to a hydrochloric acid solution to obtain a dealuminizing agent hydrochloric acid mixed solution, adding the natural mordenite powder to the dealuminizing agent hydrochloric acid mixed solution and shaking, allowing the mixture to stand after shaking, and removing the supernatant to obtain a dealuminized natural mordenite molecular sieve;

[0014] Step S13, placing the dealuminated natural mordenite molecular sieve into the copper salt solution, stirring and shaking, and then standing, and removing the supernatant to obtain a precipitate;

[0015] Step S14, after washing and filtering the precipitate with clean water, placing it in a muffle furnace for heat treatment to obtain CuO 1-x / DM catalyst.

[0016] In one embodiment, in step S2, the wastewater and the CuO 1-x The mass ratio of the catalyst to the DM is 40:1.

[0017] In one embodiment, in step S2, the constant temperature is 20-30°C.

[0018] In one embodiment, in step S11, the particle size of the natural mordenite powder is 140 mesh.

[0019] In one embodiment, the shaking time in step S12 is 2-6 hours, and the pH value of the dealuminated natural mordenite molecular sieve is 5-7.

[0020] In one embodiment, in step S13, the mass ratio of the copper salt solution to the dealuminated natural mordenite molecular sieve is 10:1.

[0021] In one embodiment, in step S13, an adsorbent is mixed in the copper salt solution, and the adsorbent is used to help the copper salt component in the copper salt solution to be loaded on the dealuminated natural mordenite molecular sieve.

[0022] In one embodiment, in step S14, the heat treatment includes drying and calcining.

[0023] The wet air catalytic oxidation method for wastewater COD degradation disclosed in the present invention converts CuO 1-x CuO supported on dealuminated natural mordenite molecular sieve (Dealuminated Mordenite DM) 1-x / DM, CuO 1-x / DM is used as catalyst to catalytically oxidize and degrade COD wastewater using wet air method. Specifically, CuO 1-x represents a copper oxide structure with oxygen defects, where X represents the proportion of oxygen defects, CuO 1-x The structure of can be regarded as a cupric oxide doped with cuprous oxide. After the copper oxide crystals that originally had no oxidative catalytic activity were introduced with oxygen vacancies (doped with cuprous oxide), their catalytic performance for organic matter was activated. The natural mordenite molecular sieve is used as a catalyst carrier, and its pore size and surface characteristics are adjustable. A suitable natural mordenite molecular sieve can be selected as a carrier according to different reaction conditions and reactants. In the present invention, the aluminum oxide in the pores of the natural mordenite molecular sieve is removed, and the natural mordenite molecular sieve is dealuminated, which not only expands the inner diameter of the pores, but also forms a very strong asymmetric electrostatic field and an asymmetric coordination field, so that the electronic layer of the transition metal ion is squeezed by the Jahn-Taylor effect, and has the possibility of paramagnetic / spin transition, which provides a low-energy barrier induction pathway for the diradical activation of molecular oxygen, so the reaction is carried out at room temperature and pressure, CuO 1-x / DM catalysts can directly induce oxygen molecules into highly active free radicals, CuO 1-x / DM, as a heterogeneous catalyst, can be easily recovered and recycled after use, which provides a pollution-free, energy-free, economical and environmentally friendly method for wet air oxidation of COD wastewater.

[0024] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0026] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices; "fixed" or "fixed connection" generally refers to common mechanical connection methods, such as threaded connection, welding or bonding, etc.

[0028] In the prior art, the key factor of wet air oxidation technology is strong oxidizing free radicals, so highly active free radicals are needed to induce diradical oxygen to enter the reaction. Currently, the commonly used catalysts are H 2 O 2 / O 2 Catalyst, H 2 O 2 / O 2 The catalyst can treat wastewater with high COD value and chromaticity, with COD removal rate up to 80% and chromaticity removal rate higher than 90%. 2 O 2 / O 2 The catalyst consumes a large amount of peroxide, the catalyst cannot be recycled, and the reaction product cannot be completely degraded into carbon dioxide and water, so the expected industrial effect cannot be achieved. The present invention discloses a method for wet air catalytic oxidation degradation of COD wastewater to at least solve the above technical problems existing in the prior art.

[0029] In view of this, the present invention aims to propose a wet air catalytic oxidation method for COD degradation of wastewater, which converts CuO 1-x CuO supported on dealuminated natural mordenite molecular sieve 1-x / DM, CuO 1-x / DM is used as catalyst to catalytically oxidize and degrade COD wastewater using wet air method.

[0030] In order to significantly increase the reaction rate, improve the removal efficiency of refractory organic pollutants, reduce the reaction time, reduce the reaction temperature and pressure, thereby obtaining better efficiency and reducing the operating cost of the technology; in a specific embodiment, the method includes the following steps:

[0031] Step S1, CuO 1-x CuO attached to dealuminated natural mordenite molecular sieve 1-x / DM catalyst; specifically, CuO 1-x As a catalytic component that induces spin transitions, CuO 1-x The choice of dealuminated natural mordenite molecular sieve (Dealuminated Mordenite DM) as a carrier has a particularly extended d electron orbital and a particularly sensitive orbital-rotation coupling degree, which plays a significant role in the catalytic performance and recovery of the catalyst.

[0032] Step S2, CuO 1-x / DM catalyst is put into COD wastewater, and then the wastewater is ventilated with an air pump until the concentration of air dissolved in the COD wastewater is saturated, and a catalytic oxidation reaction is carried out at a constant temperature; specifically, a fish tank air with a power of 60W can be used to blow air to make the air dissolved in the water reach a saturated concentration.

[0033] In order to reduce energy consumption, the method disclosed in the present invention converts CuO 1-x CuO attached to dealuminated natural mordenite molecular sieve (Dealuminated Mordenite DM) 1-x / DM, CuO 1-x / DM is used as catalyst to catalytically oxidize and degrade COD wastewater using wet air method. Specifically, CuO 1-x represents a copper oxide structure with oxygen defects, where X represents the proportion of oxygen defects, CuO 1-xThe structure can be regarded as a cupric oxide doped with cuprous oxide. After the copper oxide crystals that originally had no oxidative catalytic activity were introduced with oxygen vacancies (cuprous oxide doping), their catalytic performance towards organic matter in wastewater was activated; natural mordenite molecular sieve (DM) is used as a catalyst carrier, and its crystal structure contains five-membered rings, four-membered rings, eight-membered rings, and twelve-membered rings, that is, it is composed of many layers containing such "ring holes" overlapped and connected in an appropriate manner. The twelve-membered ring is the main airway of natural mordenite, and the adsorbed molecules mainly enter and exit this main pore. Due to a certain displacement between the layers of mordenite, the straight cylindrical pores are distorted to a certain extent, so that the average pore size of mordenite is usually reduced to about 0.4nm. In addition, since the adsorption effect depends on the shape and cross-sectional area of ​​the molecule, it is shown that natural mordenite has obvious selectivity for molecules of different sizes, but its pore size and surface characteristics are adjustable, and suitable natural mordenite molecular sieves can be selected according to different reaction conditions and reactants. In the scheme of the present invention, part of the aluminum oxide in the pores of the natural mordenite molecular sieve is removed, and the natural mordenite molecular sieve is dealuminated, which not only expands the inner diameter of the pores, but also forms a very strong asymmetric electrostatic field and asymmetric coordination field in the pores, so that the electronic layer of the transition metal ion is squeezed by the Jahn-Taylor effect, thereby having the possibility of paramagnetic / spin transition, which provides a low-energy barrier induction pathway for the diradical activation of molecular oxygen, so the reaction can be carried out at room temperature and pressure, CuO 1-x / DM catalysts can directly induce oxygen molecules into highly active free radicals, CuO 1-x / DM, as a heterogeneous catalyst, can be easily recovered and recycled after use, which provides a pollution-free, energy-free, economical and environmentally friendly method for wet air oxidation of COD wastewater.

[0034] The configuration of a supported metal catalyst can improve the catalytic performance of the catalyst and facilitate the recovery and reuse of the catalyst. In a specific embodiment, in step S1, CuO 1-x The method of / DM catalyst comprises the following steps:

[0035] Step S11, grinding and crushing the blocky natural mordenite and then sieving to obtain natural mordenite powder;

[0036] Step S12, adding a dealuminizing agent to a hydrochloric acid solution to obtain a dealuminizing agent hydrochloric acid mixed solution, adding natural mordenite powder to the dealuminizing agent hydrochloric acid mixed solution and shaking, standing after shaking, and removing the supernatant to obtain a dealuminized natural mordenite molecular sieve; wherein the dealuminizing agent added to the mineral acid solution can prevent the skeleton of the natural mordenite from collapsing during the dealuminizing formation, after removing the supernatant, washing the solid material with clean water to a pH value of 5-7 to obtain a dealuminized natural mordenite molecular sieve;

[0037] Step S13, putting the dealuminated natural mordenite molecular sieve into the copper salt solution, stirring and shaking it, then letting it stand, and pouring off the upper clear liquid to obtain a precipitate; wherein, after the dealuminated natural mordenite molecular sieve is put into the copper salt solution, it can be stirred and shaken in an ultrasonic force field, and the stirring and shaking time is not less than 0.5 hours.

[0038] Step S14, after washing and filtering the precipitate with clean water, heat-treating it in a muffle furnace to obtain CuO 1-x / DM catalyst. In order to maintain the pH value of the precipitate, the volume of clean water used to wash the precipitate is equal to that of the precipitate.

[0039] In a specific embodiment, in step S2, wastewater and CuO 1-x The mass ratio of the catalyst to the DM is 40:1.

[0040] In a specific embodiment, in step S2, the constant temperature is 20-30°C.

[0041] In order to make CuO 1-x The particles are more completely loaded on the natural mordenite molecular sieve. In a specific embodiment, in step S11, the particle size of the natural mordenite powder is 140 mesh.

[0042] In a specific embodiment, the oscillation time in step S12 is 2-6h, and the pH value of the dealuminated natural silk-denite molecular sieve is 5-7; wherein, the dealumination degree of natural silk-denite is different with different oscillation time, and the experimental results show that different dealumination degrees have a certain influence on the catalytic degradation of COD wastewater. Taking the experimental results of the dealuminated natural silk-denite molecular sieves with dealumination time of 4h and 6h as carriers as an example, the change rate of COD in the wastewater of the natural silk-denite molecular sieve with dealumination time of 4h tends to 0 after the first reaction oscillation ends; and the natural silk-denite molecular sieve with dealumination time of 6h still has a very small reaction oscillation after the first reaction oscillation, but the overall trend is still 0. By comparison, it can be seen that the effect of catalytic treatment of COD wastewater by natural silk-denite with dealumination time of 6h is better than that of natural silk-denite with dealumination time of 4h, so preferably, the oscillation time in step S12 can be 6h.

[0043] In a specific embodiment, in step S13, the mass ratio of the copper salt solution to the dealuminated natural mordenite molecular sieve is 10:1.

[0044] In a specific embodiment, in step S13, an adsorbent is mixed in the copper salt solution, and the adsorbent is used to help the copper salt component in the copper salt solution to be loaded on the dealuminated natural mordenite molecular sieve.

[0045] In a specific embodiment, in step S14, the heat treatment includes drying and calcining, wherein the calcining can activate the activity of the catalyst.

[0046] The wet air catalytic oxidation method for wastewater COD degradation proposed in the present invention uses CuO 1-x / DM as a catalyst, experiments show that CuO 1-x / DM catalyst not only allows the degradation reaction to proceed at room temperature and pressure, but can also be reused. The experimental data are as follows:

[0047] CuO 1-x When the / DM catalyst was used for the first time, the COD removal rate was 96.28%;

[0048] CuO 1-x When the / DM catalyst was used for the second time, the COD removal rate was 93.31% and the decay rate was 2.97%;

[0049] CuO 1-x When the / DM catalyst was used for the third time, the COD removal rate was 88.55% and the decay rate was 4.76%;

[0050] CuO 1-x When the / DM catalyst was used for the third time, the COD removal rate was 85.93% and the decay rate was 2.63%;

[0051] The average decay rate is (2.97%+4.76%+2.63%) / 3=3.45%;

[0052] According to this average decay rate, if the COD removal rate is to drop from 96.28% to 48.14%, the catalyst may need to be recycled 14 times, that is, the half-life of the catalyst is 14. Considering that the COD removal rate can also be increased by increasing the reaction time to extend the useful life of the catalyst. Therefore, CuO 1-x / DM catalyst has good industrial development prospects for wet air oxidation treatment of COD wastewater.

[0053] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0054] Example 1

[0055] Step S1, CuO 1-x CuO attached to dealuminated natural mordenite molecular sieve 1-x / DM catalyst;

[0056] S11, grinding and crushing the blocky natural mordenite and then sieving to obtain natural mordenite powder with a particle size of 140 mesh;

[0057] S12, adding an appropriate amount of a dealuminizing agent to a hydrochloric acid solution with a solute mass of 8 mol to obtain a dealuminizing agent hydrochloric acid mixed solution, adding natural mordenite powder to the dealuminizing agent hydrochloric acid mixed solution (the weight ratio of the added natural mordenite powder to the dealuminizing agent mineral acid mixed solution is 1:10), shaking for 6 hours and then standing, decanting the upper clear liquid, to obtain a dealuminized natural mordenite molecular sieve;

[0058] S13, adding a dealuminated natural mordenite molecular sieve to a copper salt solution having a solute mass of 0.7 mol (the weight ratio of the dealuminated natural mordenite molecular sieve added to the copper salt solution is 1:10), stirring and shaking for 0.5 h and then standing, decanting the supernatant to obtain a precipitate;

[0059] S14, washing the precipitate with clean water, filtering it, and then placing it in a muffle furnace for heat treatment to obtain CuO 1-x / DM catalyst;

[0060] Step S2, 10 g CuO 1-x / DM catalyst was put into 400 ml of wastewater, and then the COD wastewater was aerated with a 60w air pump until the air concentration in the wastewater reached saturation and then the air was stopped. The CuO1-x / DM catalyst was subjected to catalytic oxidation reaction with the wastewater at 25°C.

[0061] Comparative Example 1

[0062] Step S1, CuO 1-x CuO attached to dealuminated natural mordenite molecular sieve 1-x / DM catalyst, with CuO 1-x The steps of / DM catalyst are the same as those in Example 1;

[0063] Step S2, 10 g CuO 1-x / DM catalyst was put into 400 ml of wastewater, and then 0.4 ml of 30% hydrogen peroxide solution was added. Then the wastewater was ventilated with a 60w fish tank air pump until the concentration of air dissolved in the COD wastewater reached saturation. Then the ventilation was stopped and the mixed solution was subjected to catalytic oxidation reaction at 25°C.

[0064] Comparative Example 2

[0065] Step S1, grinding and crushing the blocky natural mordenite and then sieving to obtain natural mordenite powder with a particle size of 140 mesh;

[0066] Step S2, using the obtained natural mordenite powder as a catalyst, immersing 10 grams of natural mordenite powder into 400 milliliters of wastewater, then aerating the wastewater with a 60W fish tank air pump until the concentration of air dissolved in the COD wastewater is saturated, then stopping the aeration, and subjecting the mixed solution to a catalytic oxidation reaction at 25°C.

[0067] Comparative Example 3

[0068] Step S1, grinding and crushing a block of natural mordenite and then sieving to obtain a natural mordenite powder with a particle size of 140 mesh, adding an appropriate amount of a dealuminizing agent to a hydrochloric acid solution with a solute mass of 8 mol to obtain a dealuminizing agent hydrochloric acid mixed solution, adding natural mordenite powder to the dealuminizing agent hydrochloric acid mixed solution (the weight ratio of the added natural mordenite powder to the dealuminizing agent hydrochloric acid mixed solution is 1:10), shaking for 6 hours and then standing, decanting the supernatant to obtain a dealuminized natural mordenite molecular sieve;

[0069] Step S2, using the obtained dealuminated natural mordenite molecular sieve as a catalyst, immersing 10 grams of dealuminated natural mordenite molecular sieve into 400 milliliters of wastewater, then aerating the wastewater with a 60W fish tank air pump until the concentration of air dissolved in the COD wastewater is saturated, then stopping aeration, and subjecting the mixed solution to a catalytic oxidation reaction at 25°C.

[0070] The above examples and comparative examples are shown in Table 1.

[0071] Table 1

[0072] serial number COD removal rate Example 1 96.28％ Comparative Example 1 86.67％ Comparative Example 2 73.78％ Comparative Example 3 81.62％

[0073] It can be seen from the experimental results of the embodiments, comparative examples and Table 1 that the use of CuO 1-x / DM acts as a catalyst to catalyze and oxidize the COD in wastewater, increasing the degradation rate of COD. 1-x / DM can be recycled as a heterogeneous catalyst, which provides a pollution-free, energy-saving, economical and environmentally friendly method for wet air oxidation of wastewater.

[0074] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0075] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0076] In the several embodiments provided by the present invention, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0077] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0078] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0079] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a mobile terminal, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A wet air catalytic oxidation method for COD degradation of wastewater, characterized in that: The wet air catalytic oxidation method for wastewater COD degradation includes: Step S1, CuO 1-x CuO attached to dealuminated natural mordenite molecular sieve 1-x / DM catalyst; Step S2, the CuO 1-x / DM catalyst is immersed in wastewater, and air is introduced into the wastewater by an air pump until the air concentration in the wastewater reaches saturation, then the air is stopped, and the CuO 1-x / DM catalyst and wastewater undergo catalytic oxidation reaction at constant temperature.

2. The wet air catalytic oxidation method for wastewater COD degradation according to claim 1, characterized in that: In step S1, CuO is prepared 1-x / DM catalyst method includes, Step S11, grinding and crushing the blocky natural mordenite and then sieving to obtain natural mordenite powder; Step S2, adding a dealuminizing agent to a hydrochloric acid solution to obtain a dealuminizing agent hydrochloric acid mixed solution, adding the natural mordenite powder to the dealuminizing agent hydrochloric acid mixed solution and shaking it, allowing it to stand after shaking, and removing the supernatant to obtain a dealuminized natural mordenite molecular sieve; Step S13, placing the dealuminated natural mordenite molecular sieve into the copper salt solution, stirring and shaking, and then standing to remove the supernatant to obtain a precipitate; Step S14, after washing and filtering the precipitate with clean water, placing it in a muffle furnace for heat treatment to obtain CuO 1-x / DM catalyst.

3. The wet air catalytic oxidation method for wastewater COD degradation according to claim 1, characterized in that: In step S2, the wastewater and the CuO 1-x The mass ratio of / DM catalyst is 40:

1.

4. The wet air catalytic oxidation method for wastewater COD degradation according to claim 1, characterized in that: In step S2, the constant temperature is 20-30°C.

5. The wet air catalytic oxidation method for wastewater COD degradation according to claim 2, characterized in that: In step S11, the particle size of the natural mordenite powder is 140 mesh.

6. The wet air catalytic oxidation method for wastewater COD degradation according to claim 2, characterized in that: The shaking time in step S12 is 2-6 hours, and the pH value of the dealuminated natural mordenite molecular sieve is 5-7.

7. The wet air catalytic oxidation method for wastewater COD degradation according to claim 2, characterized in that: In step S13, the weight ratio of the copper salt solution to the dealuminated natural mordenite molecular sieve is 10:

1.

8. The wet air catalytic oxidation method for wastewater COD degradation according to claim 2, characterized in that: In step S13, an adsorbent is mixed into the copper salt solution, and the adsorbent is used to help the copper salt component in the copper salt solution to be loaded on the dealuminated natural mordenite molecular sieve.

9. The wet air catalytic oxidation method for COD degradation of wastewater according to claim 2, characterized in that: In step S14, the heat treatment includes drying and calcining.