Core-shell structure ion exchange catalyst for sludge disintegration and preparation method and device thereof

Abstract

The invention discloses a core-shell structure ion exchange catalyst for sludge disintegration and a preparation method and device thereof, and belongs to the technical field of environment. According to the core-shell structure ion exchange catalyst for sludge disintegration, the core is ion exchange resin, and the shell is ion exchange resin loaded with iron oxide capable of being attracted by a magnet. The catalyst is prepared by ion exchange adsorption, gas phase hydrolysis migration oxidation conversion and drying magnetic separation, has dual functions of catalysis and ion exchange, and is suitable for mild and rapid cracking of sludge. The cracking agent is stable in performance, and quality control is easy in the production process; when the sludge is cracked, chemicals and energy do not need to be added; and the concentration of extracellular polymeric substances and intracellular substances released by cracking is high (expressed by CODCr).

Description

Technical Field

[0001] This invention belongs to the field of environmental technology and relates to a core-shell structured ion exchange catalyst for sludge decomposition, and its preparation method and apparatus. Specifically, it relates to the preparation of a core-shell structured ion exchange catalyst by a gas-phase hydrolysis-oxidation-magnetic separation quality control method for sludge decomposition, and its preparation method and apparatus. Background Technology

[0002] Excess sludge is a solid waste discharged during wastewater treatment. It is rich in organic matter such as protein, but also contains harmful substances such as heavy metals, polycyclic aromatic hydrocarbons, and pathogens. Improper treatment can cause serious ecological and environmental problems. The disposal and utilization of sludge is difficult and is a major challenge in wastewater treatment.

[0003] Currently, the main methods for sludge treatment include sanitary landfill, composting, and incineration. Sanitary landfill consumes land resources and poses serious ecological risks, and is about to be phased out. Composting can realize the resource utilization of sludge, but sludge contains harmful components such as heavy metals, which cannot be removed by simple fermentation, limiting the agricultural use of sludge. Incineration is the most thorough and effective method for sludge treatment, but sludge has a high water content and is difficult to dehydrate, requiring deep dehydration and drying, resulting in high energy consumption. Furthermore, sludge has high nitrogen, sulfur, and heavy metal content, and incineration easily causes air pollution. The circular economy and comprehensive waste utilization have become the current mainstream. Sludge has a complex composition, rich in useful components such as proteins, polysaccharides, amino acids, and humic acid; therefore, the high-value comprehensive utilization of sludge has become a current hot topic.

[0004] Sludge has a high water content, and due to its cellular structure and the presence of extracellular polymers (EPS), it is in a colloidal state, making dewatering and component separation difficult. Therefore, extracting extracellular polymers and breaking down sludge cells are prerequisites for achieving deep dewatering and component separation of sludge, and are key to the high-value utilization of sludge. Current methods for breaking down and extracting EPS mainly include physical methods, chemical methods, combined physical and chemical methods, and biological methods (Hao Xiaodi, Gan Wei, Li Ji, et al. Development trend of high-value and high-efficiency extraction and recycling technology of sludge EPS in 2021 [J]. Journal of Environmental Science, 41(6): 2063-2078; Wan Juanjuan, Chen Guichun, Li Ruipeng, et al. Research progress on physicochemical properties of sludge and the effect of different breaking down technologies on sludge breaking down [J]. Safety and Environmental Engineering, 2024, 31(6): 207-216.). Among these cracking and extraction technologies, the ion exchange resin method has received much attention due to its advantages such as mild reaction, no damage to the useful components of sludge, low energy consumption, no secondary pollution to sludge, and convenient recycling. There are many publicly available research reports and technologies (Geng Hui, Xu Ying, Dai Xiaohu, et al. Application and prospect of ion exchange resin in sludge treatment [J]. China Environmental Science, 2022, 42(11): 5220-5228; Method for enhancing anaerobic fermentation and acid production of excess sludge using cation exchange resin, application number 2019114111801; Method for enhancing sludge biological resource utilization using acidic ion exchange resin pretreatment, application number 2021111073699; A device and method for conditioning sludge using ion exchange resin, application number 2022103750269; A method for enhancing anaerobic fermentation and hydrogen production of excess sludge using cation exchange resin, application number 2022110786208; A method for recovering sludge using acidic cation exchange resin). Processes for phosphorus and aluminum salts in sludge, application number 2023109654255; A process for enhancing sludge component separation using acidic cation exchange resin, application number 2023109654984; An application of cation exchange resin and a method for improving sludge dewatering performance, application number 2024100483424; Geng Hui, Xu Ying, Zheng Linke, et al. Cation exchange resin pretreatment to improve anaerobic digestion and methanogenesis of sludge [C], Chinese Society for Environmental Sciences et al. Proceedings of the 2022 National Conference on Organic Solid Waste Treatment and Resource Utilization, 2022: 9. (etc.). However, simple ion exchange resins only have ion exchange function, have low sludge breaking ability, and require a long reaction time; at the same time, during use, the resin is easily broken by mechanical action such as stirring and impact, affecting reuse, and separation and recycling are difficult.

[0005] Researchers have loaded catalytically active elements such as iron, copper, and manganese onto ion exchange resins and prepared novel water treatment agents through alkaline solution treatment for phosphorus recovery or heavy metal removal from wastewater. Lin Xueying et al. adsorbed iron ions onto D201 resin and then reacted it by soaking it in NH4HCO3 solution for 24 h, allowing Fe(III) to react with OH-. - Slow reactions form hydroxyl iron, preparing resin-supported hydroxyl iron oxide for the adsorption of phosphate and cadmium in water (Lin Xueying. Preparation of ion exchange resin-based hydroxyl iron composite material and its adsorption performance for phosphate and cadmium [D]. South China University of Technology, 2023.). Zhou Changyin also exchanged and adsorbed iron and copper ions onto D301 and D201 resins, treated them with a mixed solution of NaCl and NaOH, and then reduced them to obtain resin-supported iron and / or copper catalysts for the adsorption and catalytic removal of glyphosate from water (Zhou Changyin. Preparation of modified polystyrene resin and study on adsorption / oxidation removal of glyphosate from water [D]. Qingdao University of Science and Technology, 2018.). However, after loading, the resin exchange capacity decreased or even lost its exchange capacity, and the catalytic performance of the catalyst was not high, making it unsuitable for the gentle decomposition of sludge. At the same time, in the liquid-phase modified metal ion conversion to hydroxyl oxide process, the metal oxide loading was uneven, the conversion time was long, and the quality was difficult to guarantee.

[0006] Wang Chunru et al. (A method for controllable preparation of iron hydroxyl oxide, ferric oxide, and magnetite, application number 2011100962188) reacted an aqueous solution of ferrous salt with water-soluble ethylene glycol, polyethylene glycol, polyvinyl alcohol, and polyacryl alcohol to obtain iron hydroxyl oxide. The obtained iron hydroxyl oxide was then sintered at high temperature in a muffle furnace to obtain ferric oxide; under pH conditions of 8-14, the iron hydroxyl oxide was reacted with ferrous salt to obtain Fe3O4, which can be used as a catalyst. Although this method can controllably obtain iron oxide catalysts, it is all carried out in solution and requires high-temperature calcination, making the process complex, and the obtained catalyst is inconvenient to use as a powder. Xiong Xiaopeng et al. (Magnetic chitosan-nano Fe3O4 composite material and its preparation method and uses, application number 2012103476824) used NH4Fe(SO4)2 and (NH4)2Fe(SO4)2 as iron sources, reacting them in ammonia to obtain a coffee-colored chitosan / nano Fe3O4 composite material. The method utilizes ammonia fumigation to prepare nano-Fe3O4, where 3-7 nm nanoparticles aggregate into 30-70 nm Fe3O4 nanoclusters, which are uniformly dispersed within a chitosan matrix. However, the iron oxide in the composite material synthesized by this method is merely magnetic Fe3O4, which cannot guarantee uniform quality and lacks the ability to non-destructively break down sludge. Furthermore, the powder material presents challenges in the recycling and reuse of sludge.

[0007] While simple ion exchange can destabilize sludge and extract extracellular polymers under mild conditions, it cannot destroy stable substances within the sludge cells, thus limiting its destabilization capabilities. Catalytic oxidation, on the other hand, has strong destabilization capabilities, but it consumes a large amount of organic matter in the sludge and also consumes reagents and energy, making it impractical for widespread application. Furthermore, it suffers from problems such as inconsistent quality of destabilization materials, difficulty in quality control, and challenges in recycling. Summary of the Invention

[0008] To achieve high-value comprehensive utilization of sludge, this invention aims to prepare a material that does not affect the exchange capacity of ion exchange resins while introducing catalytic groups to break down sludge cells, along with a method and automated production apparatus that facilitates recycling and quality control. This invention provides a core-shell structured ion exchange catalyst for sludge breakdown, its preparation method, and apparatus.

[0009] This invention discloses a core-shell structured ion exchange catalyst for sludge degradation. Based on a macroporous cation exchange resin, it adsorbs and loads iron ions. Through ion exchange adsorption and gas-phase hydrolysis migration oxidation conversion, followed by drying and magnetic separation, a stable shell-loaded iron oxide ion exchange catalyst is obtained. This catalyst possesses dual catalytic and ion exchange functions, suitable for the mild and rapid degradation of sludge. The degradation agent exhibits stable performance, and the production process is easy to control in terms of quality. No external reagents or energy are required during sludge degradation. The degradation releases high concentrations of extracellular polymers and intracellular cytoplasm (in terms of COD). Cr express).

[0010] The preparation method of the core-shell structured ion exchange catalyst for sludge decomposition of the present invention includes the following steps: S1: Ion exchange adsorption: The pretreated ion exchange resin was soaked in a saturated ferrous ion solution, and after standing in a vacuum environment for 1-2 hours, it was adjusted to an inert gas environment, stirred evenly, and stood for 12-24 hours to separate the solid and liquid to obtain the loaded ferrous ion exchange resin. S2: Gas-phase hydrolysis, migration, oxidation, and transformation: Ammonia gas is uniformly introduced into the supported ferrous ion exchange resin, with an inlet ammonia gas concentration of 50-100 ppm. When the concentration of recovered ammonia is higher than 80-90% of the concentration of inlet ammonia, in addition to the ammonia, an inert gas containing 3-8% oxygen by volume is introduced to continue the reaction until the concentration of recovered ammonia is equal to the concentration of inlet ammonia. Then, the gas supply is stopped, the reaction is allowed to stand for 12-24 hours, heated, and then cooled naturally to room temperature to obtain a core-shell structured modified supported iron ion exchange resin. The gradient heating process is as follows: the room temperature is raised to 45-50℃ at a rate of 5-8℃ / min and held for 1-2 hours, and then raised to 70-90℃ at a rate of 2-4℃ / min and held for 1-2 hours. S3: Drying magnetic separation: Under inert gas conditions, the modified supported iron ion exchange resin is heated to 45-50℃ and held at that temperature for 1-2 hours. After purging to remove unreacted ammonia, air is introduced and the temperature is raised to 55-65℃. The modified supported iron ion exchange resin is then subjected to purging suspension oxidation and simultaneous drying. A magnetic field is applied at the direction of the purging suspension modified supported iron ion exchange resin flow to magnetically separate and collect the modified supported iron ion exchange resin that has undergone the required oxidation conversion, thus obtaining a core-shell structured ion exchange catalyst.

[0011] In S1, the ion exchange resin is preferably one of styrene-based macroporous ion exchange resin, acrylic macroporous ion exchange resin, or macroporous chelating resin. More specifically, it is one of macroporous cation exchange resin or chelating resin that can adsorb ferrous ions in water and has an adsorption capacity of not less than 1.2 mmol / g (based on dry resin).

[0012] In S3, the magnetic field strength is 0.1-0.5 Tesla.

[0013] The core-shell structured ion exchange catalyst for sludge decomposition of the present invention is prepared by the above method. It has a core-shell structure, with the core being an ion exchange resin and the shell being an iron oxide ion exchange resin loaded with a magnet.

[0014] The inert gas is either nitrogen or argon. The core-shell structured ion exchange catalyst of the present invention is used for sludge decomposition. Its decomposition effect is that the conditions are mild when decomposing sludge, no additional oxidant or catalyst is required, there is no additional energy consumption, and the amount of organic matter released during decomposition is large.

[0015] The present invention provides an apparatus for preparing a core-shell structured ion exchange catalyst for sludge decomposition, comprising: a gas-phase modified magnetron separation reactor, a gas supply system, a material collection system, and a gas condensation and recovery system; The gas-phase modified magnetron separation reactor includes a pressure-resistant and sealed reaction tank, a magnetron separator installed on the top side wall of the reaction tank, a liquid tank installed at the bottom of the reaction tank, an aeration nozzle installed at the bottom of the reaction tank cavity, a support air distribution net installed at the lower part of the reaction tank cavity, the opening of the aeration nozzle is located below the support air distribution net, a movable filter screen and a filter screen controller are installed in the reaction tank cavity, an exhaust pipe and an air inlet pipe are installed at the top of the reaction tank, a gas lifting hood is installed at one end of the exhaust pipe inside the reaction tank, a probe of an ammonia gas monitor is installed inside the gas lifting hood, an integrated heater is installed on the reaction tank wall, the heater is connected to the reaction tank heating controller, and an openable top cover is installed on the top of the reaction tank. The magnetically controlled separator on the reaction vessel includes a magnetic drive sorting cavity, a magnetic drive head, and a magnetic drive controller. The magnetic drive head is controlled by the magnetic drive controller and provides a magnetic field that can be interrupted or continued. The magnetic field is mainly distributed and acts on the magnetic drive sorting cavity and the upper part of the reaction vessel cavity. The direction of the magnetic force in the magnetic drive sorting cavity is not parallel to the vertical direction of the reaction vessel. As a preferred method, the magnetic drive head is set at the end of the magnetic drive sorting cavity that is away from the reaction vessel. The gas supply system is connected to the gas-phase modified magnetron separation reactor and is used to supply inert gas, ammonia, or air with adjustable oxygen content to the aeration nozzles and air inlet pipes of the gas-phase modified magnetron separation reactor; it is also used to adjust the pressure and gas environment inside the reaction tank. The gas lifting hood is connected to the gas condensation and recovery system for cooling and collecting the discharged ammonia gas; The magnetically controlled separator and the collection system on the reaction vessel are connected to collect the core-shell structured ion exchange catalyst.

[0016] Furthermore, the liquid tank is connected to the lowest point of the reaction vessel cavity via a pipe equipped with a first valve.

[0017] Furthermore, the air hood opening faces downwards, with its lower edge positioned higher than the upper edge of the magnetic drive sorting cavity, and the air inlet pipe opening is also higher than the upper edge of the magnetic drive sorting cavity. Furthermore, the movable filter screen is tightly fitted to the inner wall of the reaction vessel cavity, and can move freely up and down in a piston-like manner within the range of the upper edge of the supporting gas distribution screen and the magnetic drive sorting cavity under the drive of the filter screen controller.

[0018] The gas supply system includes a temperature-controlled evaporation tank and a gas source. The temperature-controlled evaporation tank includes a tank body, an aeration head located at the bottom of the tank cavity, an anti-fogging net at the top of the tank cavity, a heater, and a heater controller. An ammonia outlet pipe is located at the highest point of the tank cavity, above the anti-fogging net. An ammonia detector probe is installed near the temperature-controlled evaporation tank inside the ammonia outlet pipe. The outlet end of the ammonia outlet pipe is connected to the inlet end of the aeration spray pipe via a second valve. The gas source can provide inert gas with adjustable oxygen content at a certain pressure. This gas can be connected via pipelines through a third, fourth, and fifth valve to the inlet ports of the aeration heads at the bottom of the temperature-controlled evaporation tank cavity, the inlet ends of the aeration spray pipes at the bottom of the reaction tank, and the inlet end of the inlet pipe at the top of the reaction tank. The temperature-controlled evaporation tank is connected to an ammonia liquid addition pipe equipped with an ammonia liquid addition valve.

[0019] The material collection system includes a horn-shaped feeder, a material collection tank, and a discharge pipe equipped with a sixth valve. The opening of the horn-shaped feeder and the reaction tank are located below the magnetic drive sorting chamber. The other end of the horn-shaped feeder is connected to the material collection tank, and the bottom of the material collection tank is connected to the discharge pipe equipped with a sixth valve.

[0020] The gas condensation and recovery system includes an exhaust fan, a condenser, a condensate tank, and an external exhaust pipe connected in sequence on the exhaust pipe; an exhaust valve is installed on the exhaust pipe between the exhaust fan and the reaction tank.

[0021] The present invention discloses a method for preparing a core-shell structured ion exchange catalyst for sludge decomposition, using the above-mentioned preparation apparatus, comprising the following steps: (1) Ion exchange adsorption: Prepare a saturated ferrous ion solution and place it in the liquid tank. Open the top cover of the reaction vessel and place the pretreated ion exchange resin into the reaction vessel cavity. Close the top cover and adjust the filter screen controller so that the filter screen is below the lower edge of the magnetic drive sorting chamber, and the ion exchange resin is located between the gas distribution net and the filter screen in the reaction vessel cavity. Close all valves of the equipment, open the exhaust valve, and turn on the exhaust fan to evacuate the reaction vessel. When the pressure inside the reaction vessel reaches -0.09 to -0.06 MPa, open the first valve. Under atmospheric pressure, the saturated ferrous ion solution in the liquid tank enters the reaction vessel, making the liquid level just cover the ion exchange resin layer. Close the first valve, and continue to operate the exhaust fan to evacuate the reaction vessel. When the pressure inside the reaction vessel reaches -0.09~-0.06MPa, stop vacuuming, close the exhaust valve, maintain pressure and let stand for 1-2 hours, turn on the gas source, adjust the output inert gas oxygen content to 0, open the fourth valve, and the gas enters the reaction vessel through the aeration nozzle to stir the ion exchange resin. The reaction vessel returns to normal pressure, the gas source and the fourth valve are closed, and after standing for 12-24 hours, the gas source is turned on again, the output inert gas oxygen content is adjusted to 0, and the fifth valve and the first valve are opened. Under gas pressure, all the solution after the reaction in the reaction vessel flows back to the liquid tank. Turn off the gas source, close the fifth valve and the first valve, and the adsorption loading of ferrous ions on the ion exchange resin is completed, and the loaded ferrous ion exchange resin is obtained. (2) Gas-phase hydrolysis, migration, oxidation, and transformation: Ammonia solution with a molar concentration of 1-14 mol / L is added to the temperature-controlled evaporation tank through the inlet pipe. The third valve, the second valve, and the exhaust valve are opened to activate the gas source. The oxygen content of the output inert gas is adjusted to 0, and aeration is introduced into the temperature-controlled evaporation tank. Simultaneously, the heating controller of the temperature-controlled evaporation tank is activated to raise the temperature of the heater. The temperature-controlled evaporation tank releases alkaline gas. The gas flow rate and the temperature of the heater are adjusted to maintain an ammonia concentration of 50-100 ppm in the outlet pipe. The gas enters the reaction tank through the aeration nozzle and is evenly distributed into the loaded ferrous ion exchange resin layer by the supporting gas distribution network. It reacts with the loaded ferrous ion exchange resin, and the resulting alkaline gas is collected by the gas lifting hood and condensed in the condenser through the exhaust pipe. The condensate is collected in the condensate recovery liquid tank, and the gas is discharged externally through the external exhaust pipe after deep purification. When the reaction tank... When the ammonia detector detects that the ammonia concentration is higher than 80-90% of the inlet ammonia concentration, the oxygen volume percentage in the output gas is increased to 3-8% to continue the reaction. When the ammonia detector on the reaction vessel detects that the ammonia concentration is equal to the inlet ammonia concentration, the temperature-controlled evaporation tank heating controller and gas source are turned off, the gas supply is stopped, the second valve, the third valve and the exhaust valve are closed, the reaction vessel is sealed and allowed to stand for 12-24 hours, the reaction vessel heating controller is turned on, the reaction vessel heater works, and the temperature is increased according to the program: room temperature is increased to 45-50℃ at a rate of 5-8℃ / min and held for 1-2 hours, then increased to 70-90℃ at a rate of 2-4℃ / min and held for 1-2 hours. After that, the reaction vessel heater stops working, the reaction vessel cools naturally to room temperature, and the gas phase hydrolysis migration oxidation conversion is completed. Modified loaded iron ion exchange resin is obtained in the reaction vessel. (3) Drying and magnetic separation: Open the exhaust valve and the fourth valve, start the gas source, and adjust the output gas oxygen volume percentage to 0. Simultaneously set and turn on the reactor heating controller, and the reactor heater will start working. The reactor will gradually heat up to 45-50℃. After holding at this temperature for 1-2 hours, turn on the exhaust fan and adjust the air volume to equal the gas supply volume to purge the unreacted ammonia from the reactor. Adjust the gas source and replace the gas supply with air, with an oxygen volume percentage of 21%. The reactor will gradually heat up to 55-65℃, and the modified loaded iron ion exchange resin will continue to dry for 1-2 hours. When the modified loaded iron ion exchange resin is dried, raise the filter screen to the upper edge of the magnetic drive sorting chamber using the filter screen controller, and simultaneously adjust the exhaust... The flow rate of the blower and the output flow rate of the gas source cause the resin to be suspended. Some of the iron loaded on the resin is converted into magnetic iron oxide. When the magnetic drive controller is turned on, the magnetic drive head generates a magnetic field, which attracts the ion exchange resin suspended in the upper part of the reaction tank that has undergone the required oxidation conversion into the magnetic drive separation chamber. The resin is attracted and accumulated on the wall of the magnetic drive separation chamber on one side of the magnetic drive head. When the magnetic drive separation chamber is full of resin, the magnetic drive controller stops working, the strong magnetism of the magnetic drive head disappears, and the resin in the magnetic drive separation chamber enters the collection tank through the horn-shaped feeder under the action of gravity, realizing magnetic separation and quality control separation. The core-shell structured ion exchange catalyst in the collection tank is discharged from the discharge port, and the core-shell structured ion exchange catalyst can be used to break down sludge.

[0022] The present invention provides a core-shell structured ion exchange catalyst for sludge decomposition, as well as its preparation apparatus and method, which have the following advantages: The present invention provides a core-shell structured ion exchange catalyst for sludge breaking that retains the ion exchange capacity of macroporous ion exchange resin and generates an iron-based catalyst in situ in the shell layer, which acts as a charge-mediated and spear-like agent. It can break the tight structure of extracellular polymers and cell walls of sludge, increase the amount of exchangeable ions in sludge, and has a stronger ability to break down sludge. No external reagents or energy are required when breaking down sludge, and the amount of organic matter released during sludge breaking down is greater. By utilizing the functional groups of ion exchange resin, ion exchange loading is achieved, iron distribution is more uniform, gas-phase hydrolysis hydroxylation and gas-phase oxidation conversion are achieved, and the surface effect is used to realize the migration of iron catalyst to the resin surface to form a shell catalyst and an inner layer ion exchange group structure. Magnetic control sorting and separation enables quality control of core-shell structured ion exchange catalysts, resulting in uniform and stable product quality that is easy to industrial production and quality control. Core-shell structured ion exchange resin catalysts that can be attracted by magnetic force are easier to separate and recover during use; This invention provides an integrated device for preparing core-shell structured ion exchange catalysts for sludge decontamination. The device has a compact structure, mild and easily controllable reaction conditions, and can achieve automated production.

[0023] During the gas-phase hydrolysis, migration, oxidation, and conversion process, ammonia enters the reaction vessel at a certain initial concentration, reacts with the supported ferrous ion exchange resin, and is then collected through a gas lifting hood and sent to the gas condensation and recovery system. Ammonia gas is continuously introduced into the reaction vessel and reacts continuously with the ferrous ion exchange resin. The iron ions in the ferrous ion exchange resin undergo gas-phase hydrolysis and migrate towards the spherical resin shell under the action of surface tension, completing the gas-phase hydrolysis migration and collection. The hydrolysis process consumes ammonia gas, so the ammonia concentration in the gas flow out of the reaction vessel is very low in the early stage of the reaction. As the reaction proceeds, more and more iron in the ferrous ion exchange resin spheres completes gas-phase hydrolysis migration, and the amount of ammonia consumed decreases. The subsequently introduced ammonia gas flows out of the reaction vessel with the gas flow, and the ammonia concentration at the outlet of the reaction vessel increases. By monitoring the change in ammonia concentration at the gas lift hood, the gas-phase hydrolysis process of the ferrous ion exchange resin is judged, and the degree of gas-phase hydrolysis and migration of iron ions in the ferrous ion exchange resin towards the shell is controlled. Then, a low content of oxygen is introduced to carry out oxidation conversion to generate iron oxide. The difficult-to-control gas-phase hydrolysis migration oxidation conversion process is indicated and controlled by the change in the outlet ammonia concentration. The control is precise, stable, and simple, and can achieve automated quality control. Attached Figure Description

[0024] Figure 1 A schematic diagram of the apparatus for preparing a core-shell structured ion exchange catalyst for sludge decomposition. Figure 2 This is a schematic diagram of the internal structure of a gas-phase modified magnetron separation reactor under ion exchange and gas-phase hydrolysis-oxidation migration-transformation conditions. Figure 3 This is a schematic diagram of the internal structure of a gas-phase modified magnetron separation reactor under dry magnetic separation conditions. Figure 4 This is a schematic diagram of the internal structure of a temperature-controlled evaporation tank. Figure 5 SEM and EDS images and elemental analysis results of the core-shell structured ion exchange catalyst; Figure (a) shows the surface SEM and EDS images, and (b) shows the surface elemental analysis results; Figure 6 SEM and EDS images and elemental analysis of the central cross section of the core-shell structured ion exchange catalyst; Figure (a) shows the cross-sectional SEM and EDS images, and (b) shows the results of the cross-sectional elemental analysis. In the above diagram, 1 is the gas-phase modified magnetic separation reactor; 11 is the reaction tank; 12 is the magnetic separator; 13 is the liquid tank; 14 is the aeration nozzle; 15 is the gas distribution support net; 16 is the filter screen; 161 is the filter screen controller; 17 is the exhaust pipe; 171 is the gas lifting hood; 172 is the exhaust valve; 110 is the ammonia monitor; 18 is the heater; 181 is the reaction tank heating controller; 19 is the top cover; 121 is the magnetic drive sorting chamber; 122 is the magnetic drive head; 123 is the magnetic drive controller; 13 is the liquid tank; and 131 is the first valve. 2 is the gas supply system; 21 is the temperature-controlled evaporator, 22 is the gas source, 211 is the temperature-controlled evaporator body, 212 is the aeration head, 213 is the demisting net, 214 is the temperature-controlled evaporator heater, 215 is the temperature-controlled evaporator heating controller, 216 is the ammonia outlet pipe, 210 is the ammonia detector, 217 is the second valve, 218 is the ammonia liquid injection pipe, 219 is the ammonia liquid injection valve, 221 is the third valve, 222 is the fourth valve, 223 is the fifth valve, and 224 is the air inlet pipe. 3 represents the material collection system: 31 is the horn-shaped feeder, 32 is the material collection tank, 321 is the discharge pipe, and 322 is the sixth valve; 4 is the gas condensation and recovery system: 41 is the exhaust fan, 42 is the condenser, 43 is the condensate tank, and 431 is the external exhaust pipe. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the embodiments.

[0026] Unless otherwise specified, all concentrations used in the following examples are mass concentrations.

[0027] Example 1 A schematic diagram of an apparatus for preparing a core-shell structured ion exchange catalyst for sludge decomposition is shown below. Figure 1 Specifically, it includes: Gas-phase modified magnetron separation reactor 1, gas supply system 2, material collection system 3, gas condensation and recovery system 4; The gas-phase modified magnetron separation reactor 1 includes a pressure-resistant and sealed reaction tank 11, a magnetron separator 12 installed at the top of the reaction tank, a liquid tank 13 installed at the bottom of the reaction tank, an aeration nozzle 14 installed at the bottom of the reaction tank 11 cavity, a supporting gas distribution net 15 installed at the lower part of the reaction tank cavity, with the opening of the aeration nozzle 14 located below the supporting gas distribution net 15. A movable filter screen 16 and a filter screen controller 161 are installed inside the reaction tank cavity. An exhaust pipe 17 and an inlet pipe 224 are installed at the top of the reaction tank. A gas lifting hood 171 is installed at one end of the exhaust pipe 17 inside the reaction tank. The gas lifting hood 171 is connected to a gas condensation and recovery system 4 for cooling and collecting the discharged ammonia gas. An ammonia gas monitor 110 probe is installed inside the gas lifting hood 171. A reaction tank heater 18 and a reaction tank heating controller 181 are integrated into the reaction tank wall. An openable top cover 19 is installed on the top of the tank. The magnetically controlled separator 12 on the reaction vessel includes a magnetically driven sorting chamber 121, a magnetically driven head 122, and a magnetically driven controller 123. The magnetically driven head 122 is controlled by the magnetically driven controller 123 and provides a magnetic field that can be interrupted or continued. The magnetic field is mainly distributed and acts on the upper part of the magnetically driven sorting chamber 121 and the reaction vessel 11. The direction of the magnetic force in the magnetically driven sorting chamber 121 is not parallel to the vertical direction of the reaction vessel 11. The magnetically controlled separator 12 on the reaction vessel is connected to the collection system 3 and is used to collect the core-shell structured ion exchange catalyst.

[0028] The liquid tank 13 is connected to the lowest point of the bottom of the reaction tank 11 through a pipe equipped with a first valve 131; the gas lifting hood 171 has an opening facing downwards, and its lower edge is higher than the upper edge of the magnetic drive sorting cavity 121; the opening of the air inlet pipe 224 is also higher than the upper edge of the magnetic drive sorting cavity 121; the movable filter screen 16 is tightly matched with the inner wall of the reaction tank 11 cavity, and can move freely up and down in a piston-like manner within the range of the supporting gas distribution net 15 and the upper edge of the magnetic drive sorting cavity 121 in the reaction tank 11 cavity under the drive of the filter screen controller 161; Gas supply system 2 includes a temperature-controlled evaporator 21 and a gas source 22; a schematic diagram of the temperature-controlled evaporator 21 is shown below. Figure 4The system includes a temperature-controlled vaporizer body 211, an aeration head 212 located at the bottom of the tank cavity, an anti-fogging net 213 at the top of the tank cavity, a temperature-controlled vaporizer heater 214, and a temperature-controlled vaporizer heater controller 215. An ammonia gas outlet pipe 216 is installed at the highest point of the tank cavity above the anti-fogging net 213. An ammonia gas detector probe 210 is installed near the temperature-controlled vaporizer inside the vapor outlet pipe 216. The outlet end of the ammonia gas outlet pipe 216 is connected to the aeration head via a second valve 217. The nozzle 14 is connected to the air inlet; the gas source 22 can provide an inert gas with adjustable oxygen content at a certain pressure, which can be connected to the air inlet of the aeration head 212 at the bottom of the temperature-controlled evaporation tank 21, the air inlet of the aeration nozzle 14 at the bottom of the reaction tank 11, and the air inlet of the air inlet pipe 224 at the top of the reaction tank 11 through the third valve 221, the fourth valve 222, and the fifth valve 223 respectively; the temperature-controlled evaporation tank 21 is connected to the ammonia liquid addition pipe 218 equipped with an ammonia liquid addition valve 219.

[0029] The material collection system 3 includes a horn-shaped feeder 31, a material collection tank 32, and a discharge pipe 321 equipped with a sixth valve 322. The opening of the horn-shaped feeder 31 and the reaction tank are located below the magnetic drive sorting chamber 121. The other end of the horn-shaped feeder 31 is connected to the material collection tank 32, and the bottom of the material collection tank 32 is connected to the discharge pipe 321 equipped with the sixth valve 322.

[0030] The gas condensation and recovery system 4 includes an exhaust fan 41, a condenser 42, a condensate tank 43, and an external exhaust pipe 431 connected in sequence on the exhaust pipe 17. An exhaust valve 172 is provided on the exhaust pipe 17 between the exhaust fan 41 and the reaction tank 11.

[0031] Example 2 This embodiment describes the preparation of a core-shell structured ion exchange catalyst 1 for sludge decomposition: This embodiment uses D113 macroporous acrylic weakly acidic cation exchange resin.

[0032] Using the preparation apparatus for the core-shell structured ion exchange catalyst for sludge decomposition described in Example 1, D113 type macroporous cation exchange resin was pretreated according to conventional methods: the resin was soaked in twice its volume of 95% ethanol for 3 hours, and then rinsed with water until no alcohol odor was detected; then soaked in twice its volume of saturated brine for 20 hours, the brine was discarded, and the resin was rinsed with water until the effluent was clear; then soaked in twice its volume of 3% NaOH solution for 2 hours, the alkali was drained, and the resin was rinsed with water until it was nearly neutral; then soaked in twice its volume of 5% HCl solution for 6 hours, the acid was drained, and the resin was rinsed with water until the effluent was neutral, yielding H-type resin; the H-type resin was soaked in twice its volume of 3% NaOH solution for 2 hours, the NaOH solution was discarded, and the resin was rinsed with water until the effluent was neutral, and the resin was separated to obtain pretreated ion exchange resin for later use.

[0033] Ion exchange adsorption: Prepare a saturated ferrous sulfate solution and place it in the liquid tank 13. Open the top cover 19 of the reaction vessel 11 and add the pretreated ion exchange resin onto the gas distribution mesh 15 inside the cavity of the reaction vessel 11. The filling amount is 2 / 3 of the reaction vessel volume between the gas distribution mesh 15 and the lower edge of the magnetic drive sorting cavity 121. Reinstall the filter screen 16, close the top cover 19, and adjust the filter screen controller 161 so that the upper edge of the filter screen 16 is aligned with the lower edge of the magnetic drive sorting cavity 121. The pretreated ion exchange resin is located between the gas distribution mesh 15 and the filter screen 16 inside the cavity of the reaction vessel 11. Its structural schematic diagram is shown in [Figure 1]. Figure 2 Close all valves on the equipment, open exhaust valve 172, and turn on exhaust fan 41 to evacuate reaction tank 11. When the pressure inside reaction tank 11 reaches -0.09 MPa, open first valve 131. Under atmospheric pressure, ferrous ion solution enters reaction tank 11, ensuring the liquid level just covers the ion exchange resin layer. Close first valve 131, and continue operating exhaust fan 41 to evacuate reaction tank 11. When the pressure inside reaction tank 11 reaches -0.09 MPa, stop evacuating, close exhaust valve 172, and maintain pressure for 1-2 hours. Turn on gas source 22 and adjust the output inert gas oxygen content. When the oxygen content is 0, the fourth valve 222 is opened, and the gas enters the reaction tank 11 through the aeration nozzle 14, stirring the ion exchange resin. The reaction tank 11 returns to normal pressure, the gas source 22 and the fourth valve 222 are closed, and after standing for 12-24 hours, the gas source 22 is turned on again, and the output inert gas oxygen content is adjusted to 0. The fifth valve 223 and the first valve 131 are opened. Under gas pressure, all the solution after reaction in the reaction tank 11 flows back to the liquid tank 13. The gas source 22, the fifth valve 223 and the first valve 131 are closed, and the adsorption loading of ferrous ions in the ion exchange resin is completed, and the loaded ferrous ion exchange resin 1 is obtained. Gas-phase hydrolysis, migration, oxidation, and transformation: A 14 mol / L ammonia solution is added to the temperature-controlled evaporation tank 21 through the inlet pipe 218. The third valve 221, the second valve 217, and the exhaust valve 172 are opened. The gas source 22 is turned on, and the oxygen content of the output inert gas is adjusted to 0, aerating the temperature-controlled evaporation tank 21. Simultaneously, the heating controller 215 of the temperature-controlled evaporation tank 21 is turned on to heat the heater 214, causing the temperature-controlled evaporation tank to release alkaline gas. The gas flow rate and the temperature of the heater 214 are adjusted to maintain an ammonia concentration of 100 ppm in the outlet pipe 216. The gas then enters the reaction tank 11 through the aeration nozzle 14 and is evenly distributed into the loaded ferrous ion exchange resin layer by the supporting gas distribution net 15. The gas reacts with the resin, and the resulting alkaline gas is collected through the gas lifting hood 171 and enters the condenser 42 through the exhaust pipe 17 for condensation. The condensate is collected in the condensate recovery liquid tank 43. After deep purification, the gas is then discharged through an external... Exhaust pipe 431 discharges externally; when the ammonia detector 110 on the reaction tank 11 detects that the ammonia concentration is higher than 90% of the inlet ammonia concentration, the oxygen volume percentage in the output gas of the gas source 22 is increased to 8%, and the reaction continues. When the ammonia detector 110 on the reaction tank 11 detects that the ammonia concentration is equal to the inlet ammonia concentration, the temperature control evaporator heating controller 215 and the gas source 22 are closed, the gas supply is stopped, the second valve 217, the third valve 221 and the exhaust valve 172 are closed, the reaction tank 11 is sealed and allowed to stand for 24 hours, the reaction tank heating controller 181 is turned on, the reaction tank heater 18 works, and the temperature is increased from room temperature to 50℃ at a rate of 5℃ / min and held for 2 hours, and then increased to 90℃ at a rate of 4℃ / min and held for 2 hours. After that, the reaction tank heater 18 stops working, the reaction tank 11 is naturally cooled to room temperature, and the gas phase hydrolysis migration oxidation conversion is completed. Modified loaded iron ion exchange resin 1 is obtained in the reaction tank. Dry magnetic separation: Open exhaust valve 172 and fourth valve 222, start gas source 22, and adjust the output gas oxygen volume percentage to 0. Simultaneously set and turn on reactor heating controller 181, reactor heater 18 works, reactor gradually heats up to 50℃, and after holding at this temperature for 2 hours, turn on exhaust fan 41, adjust the air volume to equal the gas supply of gas source 22, purge unreacted ammonia in reactor 11, adjust gas source 22, and replace the gas supply with air, with oxygen volume percentage of 21%. Reactor gradually heats up to 65℃, and continue drying modified loaded iron ion exchange resin for 2 hours. When the modified loaded iron ion exchange resin is dried, raise filter screen 16 to the upper edge of magnetic drive sorting chamber 121 via filter screen controller 161. Its structural schematic diagram is shown in [reference needed]. Figure 3The flow rate of the exhaust fan 41 and the gas output flow rate of the gas source 22 are adjusted synchronously to suspend the resin. Some of the ferrous iron loaded on the resin is oxidized to form magnetic iron oxide. The magnetic drive controller 123 is turned on, and the magnetic drive head 122 generates a magnetic field, which attracts the ion exchange resin suspended in the upper part of the reaction tank 11 that has reached the required oxidation conversion into the magnetic drive separation chamber 121 and attracts it to accumulate on the magnetic drive separation chamber wall on one side of the magnetic drive head 122. When the magnetic drive separation chamber 121 is full of resin, the magnetic drive controller 123 stops working, the strong magnetism of the magnetic drive head disappears, and the resin in the magnetic drive separation chamber 121 enters the collection tank 32 through the horn feeder 31 under the action of gravity, realizing magnetic separation and quality control separation. The core-shell structure ion exchange catalyst in the collection tank 32 is discharged from the discharge port 321 to obtain the core-shell structure ion exchange catalyst 1.

[0034] The surface of the core-shell structured ion exchange catalyst 1 obtained in this embodiment was analyzed, and its SEM, EDS images and elemental analysis results are shown in [the table below]. Figure 5 ,pass Figure 5 As can be seen from (a), the catalyst maintains the spherical shape of the original resin with a smooth surface, through Figure 5 As can be seen from (b), the main surface elements are sodium carbon oxide and iron. The iron element is evenly distributed and has a mass percentage of 5.52%. Sodium carbon oxide is a component of the resin matrix, and iron is evenly loaded on the resin.

[0035] The cross-section of the core-shell structured ion exchange catalyst 1 obtained in this embodiment was examined, and its SEM, EDS images and elemental analysis results are shown below. Figure 6 ,pass Figure 6 As can be seen in (a), the catalyst profile clearly shows a core-shell structure. Figure 6 As can be seen from (b), iron is uniformly distributed in the shell. Elemental analysis of cross-sections inside the shell shows that the interior is dominated by carbon, oxygen, and sodium, with an iron content of only 0.09%, indicating a very low iron loading. The core maintains the ion exchange function of the resin, while the shell is uniformly loaded with an iron catalyst.

[0036] Example 3 This embodiment describes the preparation of a core-shell structured ion exchange catalyst 2 for sludge degradation. Using the apparatus for preparing a core-shell structured ion exchange catalyst for sludge decomposition according to Example 1, D113 type macroporous cation exchange resin was used and pretreated according to the same method as in Example 2 to obtain pretreated resin for later use.

[0037] Ion exchange adsorption: Prepare a saturated ferrous sulfate solution and place it in the liquid tank 13. Open the top cover 19 of the reaction vessel 11 and add the pretreated ion exchange resin onto the gas distribution mesh 15 inside the cavity of the reaction vessel 11. The filling amount is 2 / 3 of the reaction vessel volume between the gas distribution mesh 15 and the lower edge of the magnetic drive sorting cavity 121. Reinstall the filter screen 16, close the top cover 19, and adjust the filter screen controller 161 so that the upper edge of the filter screen 16 is aligned with the lower edge of the magnetic drive sorting cavity 121. The ion exchange resin is located between the gas distribution mesh 15 and the filter screen 16 inside the cavity of the reaction vessel 11. Its structural schematic diagram is shown below. Figure 2 Close all valves on the equipment, open exhaust valve 172, and turn on exhaust fan 41 to evacuate reaction tank 11. When the pressure inside reaction tank 11 reaches -0.08 MPa, open first valve 131. Under atmospheric pressure, ferrous ion solution enters reaction tank 11, ensuring the liquid level just covers the ion exchange resin layer. Close first valve 131, and continue operating exhaust fan 41 to evacuate reaction tank 11. When the pressure inside reaction tank 11 reaches -0.08 MPa, stop evacuating, close exhaust valve 172, maintain pressure and let stand for 1-2 hours, then turn on gas source 22 and adjust the output inert gas oxygen content. When the oxygen content is 0, the fourth valve 222 is opened, and the gas enters the reaction tank 11 through the aeration nozzle 14, stirring the ion exchange resin. The reaction tank 11 returns to normal pressure, the gas source 22 and the fourth valve 222 are closed, and after standing for 12-24 hours, the gas source 22 is turned on again, and the output inert gas oxygen content is adjusted to 0. The fifth valve 223 and the first valve 131 are opened. Under gas pressure, all the solution after reaction in the reaction tank 11 flows back to the liquid tank 13. The gas source 22, the fifth valve 223 and the first valve 131 are closed, and the adsorption loading of ferrous ions in the ion exchange resin is completed, resulting in the loaded ferrous ion exchange resin 2. Gas-phase hydrolysis, migration, oxidation, and transformation: A 10 mol / L ammonia solution is added to the temperature-controlled evaporation tank 21 through the inlet pipe 218. The third valve 221, the second valve 217, and the exhaust valve 172 are opened. The gas source 22 is turned on, and the oxygen content of the output inert gas is adjusted to 0, aerating the temperature-controlled evaporation tank 21. Simultaneously, the heating controller 215 of the temperature-controlled evaporation tank 211 is turned on to heat the heater 214, causing the temperature-controlled evaporation tank to release alkaline gas. The gas flow rate and the temperature of the heater 214 are adjusted to maintain an ammonia concentration of 80 ppm in the outlet pipe 216. The gas then enters the reaction tank 11 through the aeration nozzle 14 and is evenly distributed into the loaded ferrous ion exchange resin layer by the supporting gas distribution net 15. It reacts with the loaded ferrous ion exchange resin, and the resulting alkaline gas is collected through the gas lifting hood 171 and enters the condenser 42 through the exhaust pipe 17 for condensation. The condensate is collected in the condensate recovery liquid tank 43. After deep purification, the gas is then discharged through an external... Exhaust pipe 431 discharges externally; when the ammonia detector 110 on the reaction tank 11 detects that the ammonia concentration is higher than 85% of the inlet ammonia concentration, the oxygen volume percentage in the output gas of the gas source 22 is increased to 5%, and the reaction continues. When the ammonia detector 110 on the reaction tank 11 detects that the ammonia concentration is equal to the inlet ammonia concentration, the temperature control evaporator heating controller 215 and the gas source 22 are closed, the gas supply is stopped, the second valve 217, the third valve 221 and the exhaust valve 172 are closed, the reaction tank 11 is sealed and allowed to stand for 20 hours, the reaction tank heating controller 181 is turned on, the reaction tank heater 18 works, and the temperature is increased according to the program: room temperature is increased to 45℃ at a rate of 6℃ / min and held for 2 hours, and then increased to 80℃ at a rate of 3℃ / min and held for 2 hours. After that, the reaction tank heater 18 stops working, the reaction tank 11 is naturally cooled to room temperature, and the gas phase hydrolysis migration oxidation conversion is completed. Modified loaded iron ion exchange resin 2 is obtained in the reaction tank. Dry magnetic separation: Open exhaust valve 172 and fourth valve 222, start gas source 22, and adjust the output gas oxygen volume percentage to 0. Simultaneously set and turn on reactor heating controller 181, reactor heater 18 works, reactor gradually heats up to 50℃, maintains temperature for 2 hours, then turns on exhaust fan 41, adjusts the air volume to equal the gas supply of gas source 22, purges unreacted ammonia in reactor 11, adjusts gas source 22, replaces the gas supply with air, oxygen volume percentage is 21%, reactor gradually heats up to 60℃, continues drying modified loaded iron ion exchange resin for 2 hours. When the modified loaded iron ion exchange resin is dried, raise filter screen 16 to the upper edge of magnetic drive sorting chamber 121 via filter screen controller 161. Its structural schematic diagram is shown in [reference needed]. Figure 3The flow rate of the exhaust fan 41 and the gas output flow rate of the gas source 22 are adjusted synchronously to suspend the resin. Some of the ferrous iron loaded on the resin is oxidized to form magnetic iron oxide. The magnetic drive controller 123 is turned on, and the magnetic drive head 122 generates a magnetic field, which attracts the ion exchange resin suspended in the upper part of the reaction tank 11 that has reached the required oxidation conversion into the magnetic drive separation chamber 121 and attracts it to accumulate on the magnetic drive separation chamber wall on one side of the magnetic drive head 122. When the magnetic drive separation chamber 121 is full of resin, the magnetic drive controller 123 stops working, the strong magnetism of the magnetic drive head disappears, and the resin in the magnetic drive separation chamber 121 enters the collection tank 32 through the horn feeder 31 under the action of gravity, realizing magnetic separation and quality control separation. The core-shell structure ion exchange catalyst in the collection tank 32 is discharged from the discharge port 321 to obtain the core-shell structure ion exchange catalyst 2.

[0038] Example 4 This embodiment describes the preparation of a core-shell structured ion exchange catalyst 3 for sludge decomposition: Using the apparatus for preparing a core-shell structured ion exchange catalyst for sludge decomposition according to Example 1, D113 type macroporous cation exchange resin was used and pretreated according to the same method as in Example 2 to obtain pretreated resin for later use.

[0039] Ion exchange adsorption: Prepare a saturated ferrous sulfate solution and place it in the liquid tank 13. Open the top cover 19 of the reaction vessel 11 and add the pretreated ion exchange resin onto the gas distribution mesh 15 inside the cavity of the reaction vessel 11. The filling amount is 2 / 3 of the reaction vessel volume between the gas distribution mesh 15 and the lower edge of the magnetic drive sorting cavity 121. Reinstall the filter screen 16, close the top cover 19, and adjust the filter screen controller 161 so that the upper edge of the filter screen 16 is aligned with the lower edge of the magnetic drive sorting cavity 121. The ion exchange resin is located between the gas distribution mesh 15 and the filter screen 16 inside the cavity of the reaction vessel 11. Its structural schematic diagram is shown below. Figure 2Close all valves on the equipment, open exhaust valve 172, and turn on exhaust fan 41 to evacuate reaction tank 11. When the pressure inside reaction tank 11 reaches -0.06 MPa, open first valve 131. Under atmospheric pressure, ferrous ion solution enters reaction tank 11, ensuring the liquid level just covers the ion exchange resin layer. Close first valve 131, and continue operating exhaust fan 41 to evacuate reaction tank 11. When the pressure inside reaction tank 11 reaches -0.06 MPa, stop evacuating, close exhaust valve 172, maintain pressure and let stand for 1-2 hours, then turn on gas source 22 and adjust the output inert gas oxygen content. When the oxygen content is 0, the fourth valve 222 is opened, and the gas enters the reaction tank 11 through the aeration nozzle 14, stirring the ion exchange resin. The reaction tank 11 returns to normal pressure, the gas source 22 and the fourth valve 222 are closed, and after standing for 12-24 hours, the gas source 22 is turned on again, and the output inert gas oxygen content is adjusted to 0. The fifth valve 223 and the first valve 131 are opened. Under gas pressure, all the solution after reaction in the reaction tank 11 flows back to the liquid tank 13. The gas source 22, the fifth valve 223 and the first valve 131 are closed, and the adsorption loading of ferrous ions in the ion exchange resin is completed, and the loaded ferrous ion exchange resin 3 is obtained. Gas-phase hydrolysis, migration, oxidation, and transformation: A 1 mol / L ammonia solution is added to the temperature-controlled evaporation tank 21 through the inlet pipe 218. The third valve 221, the second valve 217, and the exhaust valve 172 are opened. The gas source 22 is turned on, and the oxygen content of the output inert gas is adjusted to 0, aerating the temperature-controlled evaporation tank 21. Simultaneously, the heating controller 215 of the temperature-controlled evaporation tank 21 is turned on to heat the heater 214, causing the temperature-controlled evaporation tank to release alkaline gas. The gas flow rate and the temperature of the heater 214 are adjusted to maintain an ammonia concentration of 50 ppm in the outlet pipe 216. The gas then enters the reaction tank 11 through the aeration nozzle 14 and is evenly distributed into the loaded ferrous ion exchange resin layer by the supporting gas distribution net 15. It reacts with the loaded ferrous ion exchange resin, and the resulting alkaline gas is collected through the gas lifting hood 171 and enters the condenser 42 through the exhaust pipe 17 for condensation. The condensate is collected in the condensate recovery liquid tank 43. After deep purification, the gas... External exhaust pipe 431 exhausts externally; when the ammonia detector 110 on the reaction tank 11 detects that the ammonia concentration is higher than 80% of the inlet concentration, the oxygen volume percentage in the output gas of the gas source 22 is increased to 3%, and the reaction continues. When the ammonia detector 110 on the reaction tank 11 detects that the ammonia concentration is equal to the inlet concentration, the temperature control evaporator heating controller 215 and the gas source 22 are closed, the gas supply is stopped, the second valve 217, the third valve 221 and the exhaust valve 172 are closed, the reaction tank 11 is sealed and allowed to stand for 12 hours, the reaction tank heating controller 181 is turned on, the reaction tank heater 18 works, and the temperature is increased according to the program: room temperature is increased to 45℃ at a rate of 5℃ / min and held for 1 hour, and then increased to 70℃ at a rate of 2℃ / min and held for 1 hour. After that, the reaction tank heater 18 stops working, the reaction tank 11 is naturally cooled to room temperature, and the gas phase hydrolysis migration oxidation conversion is completed. Modified loaded iron ion exchange resin 3 is obtained in the reaction tank. Dry magnetic separation: Open exhaust valve 172 and fourth valve 222, start gas source 22, and adjust the output gas oxygen volume percentage to 0. Simultaneously set and turn on reactor heating controller 181, reactor heater 18 works, reactor gradually heats up to 45℃, maintains temperature for 1 hour, then turns on exhaust fan 41, adjusts the air volume to equal the gas supply of gas source 22, purges unreacted ammonia in reactor 11, adjusts gas source 22, replaces the gas supply with air, oxygen volume percentage is 21%, reactor gradually heats up to 55℃, continues drying modified loaded iron ion exchange resin for 1 hour. When the modified loaded iron ion exchange resin drying is complete, raise filter screen 16 to the upper edge position of magnetic drive sorting chamber 121 through filter screen controller 161. Its structural schematic diagram is shown in [reference needed]. Figure 3The flow rate of the exhaust fan 41 and the gas output flow rate of the gas source 22 are adjusted synchronously to suspend the resin. Some of the ferrous iron loaded on the resin is oxidized to form magnetic iron oxide. The magnetic drive controller 123 is turned on, and the magnetic drive head 122 generates a magnetic field, which attracts the ion exchange resin suspended in the upper part of the reaction tank 11 that has reached the required oxidation conversion into the magnetic drive separation chamber 121 and attracts it to accumulate on the magnetic drive separation chamber wall on one side of the magnetic drive head 122. When the magnetic drive separation chamber 121 is full of resin, the magnetic drive controller 123 stops working, the strong magnetism of the magnetic drive head disappears, and the resin in the magnetic drive separation chamber 121 enters the collection tank 32 through the horn feeder 31 under the action of gravity, realizing magnetic separation and quality control separation. The core-shell structure ion exchange catalyst in the collection tank 32 is discharged from the discharge port 321 to obtain the core-shell structure ion exchange catalyst 3.

[0040] Example 5 This embodiment describes the preparation of core-shell structured ion exchange catalyst 4 for sludge decomposition: Similar to Example 3, except that the macroporous resin used is type D407. Type D407 resin is a chelating ion exchange resin product with imine diacetic acid groups [-N-(CH2COOH)2] on the benzene ring of styrene-divinylbenzene copolymer spheres with macroporous structure, resulting in core-shell structured ion exchange catalyst 4.

[0041] Example 6 This embodiment describes the preparation of a core-shell structured ion exchange catalyst 5 for sludge decomposition: Similar to Example 3, except that the macroporous resin used is type D001. Type D001 resin is a macroporous strong acid cation exchange resin with styrene-divinylbenzene as the matrix and strong acid sulfonic acid groups (-SO3H) to obtain the core-shell structure ion exchange catalyst 5.

[0042] Comparative Example 1 Using D113 type macroporous ion exchange resin, in the gas phase hydrolysis migration oxidation conversion step, the temperature is directly raised to 80℃ and held for 2 hours, thus eliminating the core-shell structure.

[0043] Comparative Example 2 When using D113 type macroporous ion exchange resin, ammonia is directly introduced into the gas phase hydrolysis migration oxidation conversion process without the introduction of oxygen, so the catalyst cannot be attracted by magnetic force.

[0044] Comparative Example 3 D113 type macroporous ion exchange resin was used to adsorb divalent iron ions and then directly soaked in 1 mol / L ammonia solution. After liquid-phase modification, it was directly placed in a vacuum drying oven to dry, thus obtaining resin-loaded iron compound material.

[0045] Comparative Example 4 If D113 type macroporous ion exchange resin is used to adsorb divalent iron, and there is no subsequent process to promote the introduction of oxygen, the synthesized core-shell structure ion exchange catalyst will not be magnetic and cannot be magnetically separated for quality control.

[0046] Application Example 7 This application example demonstrates an experiment using a core-shell structured ion exchange catalyst to break down sludge: Fresh residual sludge from a wastewater treatment plant was collected, and its moisture content was adjusted to 97.5%. The sludge was passed through a 40-mesh sieve to remove large particles of sand and gravel. 100 mL of the sludge that passed through the sieve was placed in a 250 mL beaker, and 10 g of the core-shell ion exchange catalyst prepared in this embodiment of the invention or other comparative disintegrating agents were added. The mixture was magnetically stirred for 3 hours. A magnet was placed at the bottom of the beaker to hold the core-shell ion exchange catalyst in place. The sludge was then poured out to separate it from the catalyst. When using other comparative disintegrating agents, filtration was performed to separate the disintegrating agents. The resulting disintegrated residual sludge was centrifuged at 8000 r / min for 10 minutes. The supernatant was collected, and the COD was determined using a water quality analyzer. Cr DNA was determined using the diphenylamine method for the determination of total nitrogen and total phosphorus. The results are shown in Table 1.

[0047] Table 1. Sludge-breaking performance of the core-shell structured ion exchange catalyst synthesized in this invention. Various indicators of sludge supernatant CODCr (mg / L) Total nitrogen (mg / L) Total phosphorus (mg / L) DNA (mg / L) Unresolved sludge supernatant 90 6.5 1.8 Not detected After Catalyst 1 was cracked 5350 2188.9 921.5 501.2 After Catalyst 2 was cracked 5410 2260.3 997.9 509.1 After Catalyst 3 was cracked 4980 1896.2 839.5 482.9 Catalyst 4 after cracking 5120 1994.2 919.4 497.8 After Catalyst 5 was cracked 4860 1873.1 862.7 490.6 Comparative Example 1 1130 420.2 213.4 38.2 Comparative Example 2 1680 498.1 225.7 47.5 Comparative Example 3 950 367.3 196.0 32.3 Comparative Example 4 1020 398.2 201.3 33.8 D113 resin 207 48.7 84.6 Not detected D407 resin 182 58.6 80.7 Not detected D001 resin 215 93.3 83.0 Not detected As can be seen, the core-shell structured ion exchange catalyst prepared in this invention for sludge breakdown releases significantly higher levels of SCOD, total nitrogen, and total phosphorus after sludge breakdown compared to the comparative example and the untreated ion exchange resin. DNA is typically found within sludge cells, and the DNA content in the supernatant is a commonly used indicator for assessing sludge cell breakdown. After sludge breakdown treatment with the core-shell structured ion exchange catalyst prepared in this invention, the DNA release from the sludge is sufficient, and COD is significantly reduced. Cr The release of total nitrogen (mg / L) is 54-60 times higher than that of untreated sludge supernatant, the release of total nitrogen (mg / L) is 291-348 times higher than that of untreated sludge supernatant, the release of total phosphorus (mg / L) is 466-555 times higher than that of untreated sludge supernatant, and DNA is undetectable at 482-510 mg / L. The core-shell structured ion exchange catalyst of this invention exhibits excellent sludge-dissolving performance.

Claims

1. A core-shell structured ion exchange catalyst for sludge decomposition, characterized in that, The core-shell structured ion exchange catalyst for sludge decomposition has a core-shell structure, with the core being an ion exchange resin and the shell being an iron oxide ion exchange resin loaded with a magnet. It is prepared by ion exchange adsorption, gas-phase hydrolysis migration oxidation conversion, and drying magnetic separation.

2. The method for preparing the core-shell structured ion exchange catalyst for sludge decomposition as described in claim 1, characterized in that, Includes the following steps: S1: Ion exchange adsorption: The pretreated ion exchange resin was soaked in a saturated ferrous ion solution, and after standing in a vacuum environment for 1-2 hours, it was adjusted to an inert gas environment, stirred evenly, and stood for 12-24 hours to separate the solid and liquid to obtain the loaded ferrous ion exchange resin. S2: Gas-phase hydrolysis, migration, oxidation, and transformation: Ammonia gas is uniformly introduced into the supported ferrous ion exchange resin, with an inlet ammonia gas concentration of 50-100 ppm. When the concentration of recovered ammonia is higher than 80-90% of the concentration of inlet ammonia, in addition to the ammonia, an inert gas containing 3-8% oxygen by volume is introduced to continue the reaction; when the concentration of recovered ammonia is equal to the concentration of inlet ammonia, the gas supply is stopped, the reaction is allowed to stand for 12-24 hours, then heated with a gradient temperature increase and naturally cooled to room temperature to obtain the core-shell structured modified supported iron ion exchange resin. S3: Drying magnetic separation: Under inert gas conditions, the modified supported iron ion exchange resin is heated to 45-50℃ and held at that temperature for 1-2 hours. After purging to remove unreacted ammonia, air is introduced and the temperature is raised to 55-65℃. The modified supported iron ion exchange resin is then subjected to purging suspension oxidation and simultaneous drying. A magnetic field is applied at the direction of the purging suspension modified supported iron ion exchange resin flow to magnetically separate and collect the modified supported iron ion exchange resin that has undergone the required oxidation conversion, thus obtaining a core-shell structured ion exchange catalyst.

3. The method for preparing the core-shell structured ion exchange catalyst for sludge decomposition according to claim 2, characterized in that, In S1, the ion exchange resin is one of styrene-based macroporous ion exchange resin, acrylic-based macroporous ion exchange resin, and macroporous chelating resin. And / or, in S2, the gradient heating process is as follows: the room temperature is raised to 45-50℃ at a rate of 5-8℃ / min and held for 1-2 hours, and then raised to 70-90℃ at a rate of 2-4℃ / min and held for 1-2 hours. And / or, in S3, the magnetic field strength is 0.1-0.5 Tesla.

4. A core-shell structured ion exchange catalyst for sludge decomposition, characterized in that, It is prepared by the method described in claim 2 or 3.

5. An apparatus for preparing a core-shell structured ion exchange catalyst for sludge decomposition, characterized in that, The apparatus for preparing the core-shell structured ion exchange catalyst for sludge decomposition includes a gas-phase modified magnetron separation reactor (1), a gas supply system (2), a material collection system (3), and a gas condensation and recovery system (4). The gas-phase modified magnetron separation reactor (1) includes a pressure-resistant and sealed reaction vessel (11), a magnetron separator (12) installed at the top of the reaction vessel (11), a liquid tank (13) installed at the bottom of the reaction vessel (11), an aeration nozzle (14) installed at the bottom of the cavity of the reaction vessel (11), and a supporting gas distribution net (15) installed at the lower part of the cavity of the reaction vessel; the opening of the aeration nozzle (14) is located below the supporting gas distribution net (15), and a movable filter screen (16) is installed in the cavity of the reaction vessel. The filter screen (16) and the filter screen controller (161) are connected; an exhaust pipe (17) and an inlet pipe (224) are provided on the upper part of the reaction tank. A gas lifting hood (171) is provided at one end of the exhaust pipe (17) inside the reaction tank. The probe of the ammonia monitor (110) is provided inside the gas lifting hood (171). A heater (18) is provided on the wall of the reaction tank. The heater (18) is connected to the reaction tank heating controller (181). An openable top cover (19) is provided on the top of the reaction tank (11). The magnetically controlled separator (12) includes a magnetic drive sorting cavity (121), a magnetic drive head (122), and a magnetic drive controller (123). The magnetic drive head (122) is controlled by the magnetic drive controller (123) and provides a magnetic field that can be interrupted or continued. The magnetic field is mainly distributed and acts on the upper part of the magnetic drive sorting cavity (121) and the reaction tank (11). The direction of the magnetic force in the magnetic drive sorting cavity (121) is not parallel to the vertical direction of the reaction tank (11). The gas supply system (2) is connected to the gas phase modified magnetron separation reactor (1) and is used to supply the aeration nozzle (14) and air inlet pipe (224) of the gas phase modified magnetron separation reactor (1) with an adjustable oxygen content of inert gas, ammonia or air; and to adjust the pressure and gas environment inside the reaction tank. The gas lifting hood (171) is connected to the gas condensation and recovery system (4) for cooling and collecting the discharged ammonia gas; The magnetic separator (12) is connected to the collection system (3) for collecting core-shell structured ion exchange catalysts.

6. The apparatus for preparing a core-shell structured ion exchange catalyst for sludge decomposition according to claim 5, characterized in that, The gas supply system (2) includes a temperature-controlled evaporator (21) and a gas source (22); the temperature-controlled evaporator (21) includes a temperature-controlled evaporator body (211), an aeration head (212) set at the bottom of the tank cavity, a fog-reducing net (213) at the top of the tank cavity, a temperature-controlled evaporator heater (214), and a temperature-controlled evaporator heating controller (215) connected to the temperature-controlled evaporator heater (214); an ammonia gas outlet pipe (216) is set at the highest point of the tank cavity above the fog-reducing net (213) at the top of the temperature-controlled evaporator (211), and an ammonia gas detector (210) probe is set in the ammonia gas outlet pipe (216) near the temperature-controlled evaporator, and the outlet end of the ammonia gas outlet pipe (216) is connected to the inlet end of the aeration spray pipe (14) through a second valve (217); The gas source (22) provides pressurized inert gas with adjustable oxygen content. The gas source (22) is connected to the air inlet of the aeration head (212) at the bottom of the temperature-controlled evaporation tank (21) through a pipe equipped with a third valve (221). The gas source (22) is connected to the air inlet of the aeration spray pipe (14) at the bottom of the reaction tank (11) through a pipe equipped with a fourth valve (222). The gas source (22) is connected to the air inlet of the air inlet pipe (224) at the top of the reaction tank (11) through a pipe equipped with a fifth valve (223). The temperature-controlled evaporation tank (21) is connected to the ammonia dosing pipe (218) equipped with an ammonia dosing valve (219).

7. The apparatus for preparing a core-shell structured ion exchange catalyst for sludge decomposition according to claim 5, characterized in that, The material collection system (3) includes a horn-shaped feeder (31), a material collection tank (32), and a discharge pipe (321) equipped with a sixth valve (322). The opening of the horn-shaped feeder (31) and the reaction tank are located below the magnetic drive sorting chamber (121). The other end of the horn-shaped feeder (31) is connected to the material collection tank (32), and the bottom of the material collection tank (32) is connected to the discharge pipe (321) equipped with a sixth valve (322).

8. The apparatus for preparing a core-shell structured ion exchange catalyst for sludge decomposition according to claim 5, characterized in that, The gas condensation recovery system (4) includes an exhaust fan (41), a condenser (42), a condensate tank (43), and an external exhaust pipe (431) connected in sequence on the exhaust pipe (17); an exhaust valve (172) is provided between the exhaust fan (41) and the reaction tank (11) on the exhaust pipe (17).

9. A method for preparing a core-shell structured ion exchange catalyst for sludge decomposition, characterized in that, The preparation apparatus according to any one of claims 5-8 comprises the following steps: (1) Ion exchange adsorption: Prepare a saturated ferrous ion solution and place it in the liquid tank (13); open the top cover (19) of the reaction vessel (11), place the pretreated ion exchange resin in the cavity of the reaction vessel (11), close the top cover (19), adjust the filter screen controller (161) so that the filter screen (16) is below the lower edge of the magnetic drive sorting cavity (121), and the ion exchange resin is located between the gas distribution net (15) and the filter screen (16) in the cavity of the reaction vessel (11). Close all valves of the equipment, open the exhaust valve (172), turn on the exhaust fan (41), and evacuate the reaction vessel (11). When the pressure inside the reaction vessel (11) reaches -0.09~-0.06MPa, under the action of atmospheric pressure, the saturated ferrous ion solution in the liquid tank (13) enters the reaction vessel (11) and makes the liquid level just cover the ion exchange resin layer. Close the liquid tank switch, and the exhaust fan (41) continues to work to evacuate the reaction vessel (11). When the pressure inside the reaction tank (11) reaches -0.09~-0.06MPa, stop vacuuming, close the exhaust valve (172), keep the pressure and stand for 1-2 hours, turn on the gas source (22), adjust the output inert gas oxygen content to 0, open the fourth valve (222), the gas enters the reaction tank (11) through the aeration nozzle (14), stir the ion exchange resin, the reaction tank (11) returns to normal pressure, close the gas source (22) and the fourth valve (222), stand for 12-24 hours, turn on the gas source (22) again, adjust the output inert gas oxygen content to 0, open the fifth valve (223) and the first valve (131), under gas pressure, all the solution after reaction in the reaction tank (11) flows back to the liquid tank (13), close the gas source (22), close the fifth valve (223) and the first valve (131), complete the adsorption loading of ferrous ions in the ion exchange resin, and obtain the loaded ferrous ion exchange resin; (2) Gas-phase hydrolysis, migration, oxidation, and transformation: Ammonia solution with a molar concentration of 1-14 mol / L is added to the temperature-controlled evaporator (21) through the inlet pipe (218). The third valve (221), the second valve (217), and the exhaust valve (172) are opened. The gas source (22) is turned on, and the oxygen content of the output inert gas is adjusted to 0. Aeration is introduced into the temperature-controlled evaporator (21). At the same time, the heating controller (215) of the temperature-controlled evaporator (21) is turned on to heat the heater (214) of the temperature-controlled evaporator. The temperature-controlled evaporator volatilizes alkaline gas. The gas flow rate and temperature control are adjusted. The temperature of the evaporator heater (214) ensures that the ammonia concentration in the outlet pipe (216) is between 50-100 ppm. The gas enters the reaction tank (11) through the pipeline via the aeration nozzle (14), and is evenly distributed into the loaded ferrous ion exchange resin layer by the supporting gas distribution net (15). It reacts with the loaded ferrous ion exchange resin, and the alkaline gas after the reaction is collected by the gas lifting hood (171) and enters the condenser (42) through the exhaust pipe (17) for condensation. The condensate is collected in the condensate recovery liquid tank (43). After deep purification, the gas is discharged through the external exhaust pipe. (431) External discharge; when the ammonia detector (110) on the reaction tank (11) detects that the ammonia concentration is higher than 80-90% of the inlet concentration, increase the oxygen volume percentage in the output gas of the gas source (22) to 3-8% and continue the reaction. When the ammonia detector (110) on the reaction tank (11) detects that the ammonia concentration is equal to the inlet concentration, close the temperature-controlled evaporator heating controller (215) and the gas source (22), stop the gas supply, and close the second valve (217), the third valve (221) and the exhaust valve (172). ), the sealed reaction vessel (11) is left to stand for 12-24 hours, the reaction vessel heating controller (181) is turned on, the reaction vessel heater (18) is turned on, and the temperature is increased to 45-50℃ at a rate of 5-8℃ / min and held for 1-2 hours, and then increased to 70-90℃ at a rate of 2-4℃ / min and held for 1-2 hours. After that, the reaction vessel heater (18) stops working, the reaction vessel (11) is naturally cooled to room temperature, and the gas phase hydrolysis migration oxidation conversion is completed. Modified loaded iron ion exchange resin is obtained in the reaction vessel. (3) Drying and magnetic separation: Open the exhaust valve (172) and the fourth valve (222), start the gas source (22), and adjust the oxygen volume percentage of the output gas to 0. Simultaneously set and turn on the reactor heating controller (181), and the reactor heater (18) will work. The reactor will gradually heat up to 45-50℃. After holding the temperature for 1-2 hours, turn on the exhaust fan (41) and adjust the air volume to be equal to the gas supply of the gas source (22). Purge the unreacted ammonia in the reactor (11). Adjust the gas source (22) and replace the gas supply with air. The oxygen volume percentage will be 21%. The reactor will gradually heat up to 55-65℃. Continue to dry the modified loaded iron ion exchange resin for 1-2 hours. When the modified loaded iron ion exchange resin is dried, raise the filter screen (16) to the upper edge of the magnetic drive sorting chamber (121) through the filter screen controller (161). Simultaneously adjust the exhaust fan (41). The flow rate and gas source (22) output gas flow rate cause the resin to be suspended. Some of the iron loaded on the resin is converted into magnetic iron oxide. The magnetic drive controller (123) is turned on, and the magnetic drive head (122) generates a magnetic field, which attracts the ion exchange resin suspended in the upper part of the reaction tank (11) to the magnetic drive separation chamber (121) after the oxidation conversion meets the requirements. The resin is attracted and accumulated on the magnetic drive separation chamber wall on one side of the magnetic drive head (122). When the resin in the magnetic drive separation chamber (121) is full, the magnetic drive controller (123) stops working, the strong magnetism of the magnetic drive head disappears, and the resin in the magnetic drive separation chamber (121) enters the collection tank (32) through the horn feeder (31) under the action of gravity, realizing magnetic separation quality control separation. The core-shell structure ion exchange catalyst in the collection tank (32) is discharged from the discharge port (321) to obtain the core-shell structure ion exchange catalyst, which can be used to break sludge.

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