Composite nanometer zero-valent iron material pretreatment pyridine wastewater device and treatment method thereof

Abstract

The present invention discloses a composite nano zero-valent iron material pretreatment pyridine wastewater device and a treatment method thereof, the wastewater device comprises: a nano zero-valent iron synthesis tank, a solid-liquid separation tank, a wastewater reaction tank, a Fenton tank, and a sedimentation tank connected in sequence; the wastewater reaction tank comprises an inclined tube sedimentation zone, a mixed reaction zone, a dense reaction zone, and a porous support layer arranged in sequence; the Fenton tank comprises an acid adjustment zone, a Fenton reaction zone, and an alkali adjustment zone connected in sequence. The present invention can quickly and conveniently produce nano zero-valent iron on site, avoid the drying, transportation, and oxidation of nano zero-valent iron, wet addition of nano zero-valent iron, isolate air contact to a certain extent, ensure the effectiveness of nano zero-valent iron, better redox properties, lower oxidation degree, higher utilization rate, etc.; the entire system has a simple structure, convenient operation and maintenance, and low cost, and is more flexible than conventional advanced oxidation technology.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a device for pretreating pyridine wastewater using a composite nanometer zero-valent iron material and a treatment method thereof. Background Art

[0002] Pyridine-based derivative pesticide products are mainly chemical products such as dichloropyralid, tetrachloropyralid, pentachloropyridine and 2,3,5,6-tetrachloropyridinethiol. The production process of pyridine pesticides is relatively complicated, involving processes such as chlorination substitution, hydrolysis and carboxylation, and esterification. As a result, the chemical substances contained in the wastewater are relatively complex, reflecting the following characteristics: (1) high concentration of organic pollutants; (2) complex wastewater composition; (3) most of the wastewater is highly toxic, inhibiting microbial activity and difficult to biodegrade. In addition, there are also a lot of substances such as chloride ions, chloropyridines, and chloropyridine-containing fatty acids, which leads to poor effects of advanced oxidation processes such as ozone and Fenton. If this type of wastewater cannot be treated well, it will cause great harm to the environment.

[0003] The aromatic heterocyclic rings of pyridine derivatives are extremely stable. Conventional COD detection methods such as potassium dichromate method are difficult to reflect the concentration of pyridine heterocyclic rings. The national standard method of gas chromatography detection only has the method of detecting pyridine content, which cannot effectively reflect the concentration of pyridine derivatives. The COD index cannot judge the concentration of organic matter, which increases the difficulty of treatment. The current treatment process of pyridine derivatives is mainly advanced oxidation method, physical method, biological method and the combination of three processes. Advanced oxidation method is divided into wet oxidation method, Fenton oxidation method, ozone oxidation method, electrocatalytic oxidation method and other treatment methods; physical method treatment of pesticide wastewater is adsorption method, stripping method, distillation method, precipitation method, etc.; the key to biological treatment technology is to screen out special degradation bacteria for heterocyclic organic pollutants in wastewater or develop new technologies and new processes that combine multiple technologies. The current chemical, physical and biological methods for heterocyclic pesticide wastewater treatment have their own advantages and limitations. In the actual treatment of heterocyclic pesticide wastewater, due to the complexity and diversity of organic pollutants in the water, it is difficult to achieve standard discharge using a single process.

[0004] Conventional Fe-C micro-electrolysis is used to treat pyridine wastewater. An external power source is used to promote the Fe-C micro-electrolysis reaction, which consumes a lot of energy and produces a large amount of iron sludge, which is easily deposited in the pool and is difficult to operate and clean.

[0005] Nano zero-valent iron catalytic materials have the advantages of low price, large specific surface area, strong reducibility, excellent adsorption and reaction activity, etc. They can degrade various environmental pollutants (such as heavy metals, inorganic anions, halogenated organic compounds, nitroaromatic compounds, etc.) through different mechanisms. They are regarded as a new material with broad application prospects. They also have excellent removal effects on aromatic heterocycles of pyridine derivatives. By using the stronger redox agent of modified nano zero-valent iron, they can effectively carry out degradation and reduction, reduce its biological toxicity, enhance its biodegradability, and achieve better pretreatment effects.

[0006] Although nano zero-valent iron performs well in environmental governance, there are still many problems, mainly manifested in the following two points: nano zero-valent iron particles are small, have high surface energy, and have a tendency to spontaneously agglomerate, which will greatly reduce the surface energy; the precipitates such as iron hydroxide generated by the reaction will coat the surface of nano zero-valent iron, inhibiting the further reaction of the internal zero-valent iron, making the material usage far exceed the theoretical value, resulting in waste. In order to prevent the agglomeration of nano zero-valent iron particles and enhance their stability, materials such as graphite, bentonite, activated carbon, etc. can be used as carriers to carry nano zero-valent iron, so that it is evenly distributed on the surface of the carrier, and its migration ability in the solution is significantly enhanced. The existing load materials are relatively single, and the synthetic materials remain in the laboratory stage. It is easy to oxidize and difficult to store, which is a big problem. As a result, the effective reaction is inhibited in dealing with complex industrial wastewater environments. How to use new composite nano zero-valent iron materials in actual pyridine-based derivative pesticide products has become a hot topic. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a device for pretreating pyridine wastewater using a composite nanometer zero-valent iron material and a treatment method thereof.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] A composite nano zero-valent iron material pretreatment pyridine wastewater device, comprising: a nano zero-valent iron synthesis tank, a solid-liquid separation tank, a wastewater reaction tank, a Fenton tank, and a sedimentation tank connected in sequence;

[0010] The wastewater reaction tank comprises an inclined tube sedimentation zone, a mixing reaction zone, a dense reaction zone, and a porous supporting layer which are arranged in sequence; the Fenton tank comprises an acid adjustment zone, a Fenton reaction zone, and an alkali adjustment zone which are connected in sequence.

[0011] Preferably, the nano zero-valent iron synthesis tank comprises a tank body, a ferrous ion dosing port, a potassium borohydride dosing port, a nitrogen inlet, a first gas discharge port, a first agitator, a first pressure gauge, a first loading and unloading port, a reflux port, a first water outlet, a first water outlet pipe, and a reflux pipe arranged on the tank body; the nano zero-valent iron synthesis tank is used to synthesize biochar-nickel loaded nano zero-valent iron material;

[0012] The head of the first agitator is placed on the top of the tank body, and the stirring part passes through the tank body and is placed inside it; the first gas exhaust port is placed on one side of the first agitator, and the first pressure gauge is placed on the other side of the first agitator; the ferrous ion dosing port, potassium borohydride dosing port, and nitrogen gas inlet are all correspondingly arranged on one side of the tank body; the first loading and unloading port and the reflux port are correspondingly arranged on the other side of the tank body; the first water outlet is arranged at the bottom of the tank body; one end of the first water outlet pipe is connected to the first water outlet, and the other end is connected to the solid-liquid separation tank; one end of the reflux pipe is connected to the reflux port, and the other end is connected to the solid-liquid separation tank.

[0013] Preferably, the solid-liquid separation tank includes a second tank body, and a liquid inlet, a second gas exhaust port, a second water outlet, and a drain pipe arranged on the second tank body, and a tee arranged on the second water outlet; the second gas exhaust port is arranged on the top of the second tank body; the liquid inlet is arranged on the upper side of the second tank body; the second water outlet is arranged at the bottom of the tank body; the other end of the first water outlet pipe is connected to the liquid inlet of the solid-liquid separation tank; the other end of the reflux pipe is connected to one end of the tee of the solid-liquid separation tank; one end of the drain pipe is connected to the other end of the tee.

[0014] Preferably, the wastewater reaction tank includes a third tank body, and a spare water outlet, a third gas discharge port, a second pressure gauge, a third water outlet, a second water outlet pipe connected to the third water outlet, two second loading and unloading ports, a reflux pipeline, a composite zero-valent iron material discharge port, and a wastewater inlet; the spare water outlet, the third gas discharge port, and the second pressure gauge are all arranged on the top of the tank body, the third gas discharge port is arranged on one side of the spare water outlet, and the second pressure gauge is arranged on the other side of the spare water outlet; the third water outlet The inlet is arranged on the upper side of the tank body and is placed above the inclined tube sedimentation area; the composite zero-valent iron material discharge inlet is connected to the other end of the drainage pipe of the solid-liquid separation tank, and the composite zero-valent iron material discharge inlet is opened on one side of the dense reaction area; the two second loading and unloading ports are opened on the other side of the dense reaction area; one end of the reflux pipeline is arranged on the other side of the dense reaction area, and the other end is arranged below the porous supporting layer; the wastewater inlet is arranged at the bottom of the tank body, and a drain port is also arranged on one side of the wastewater inlet, and the water inlet end of the wastewater inlet is also connected to a wastewater inlet pipe.

[0015] Preferably, the acid adjustment zone, Fenton reaction zone and alkali adjustment zone are each provided with a second agitator, a third agitator and a fourth agitator respectively; the pH range of the acid adjustment zone is 3-3.5; the pH range of the alkali adjustment zone is 8-8.5.

[0016] The present invention also provides a method for treating pyridine wastewater using a composite nano zero-valent iron material pretreatment device, comprising the following steps:

[0017] Step 1, preparing biochar-nickel material: soaking the biochar in an appropriate amount of NiCl6·6H2O solution, stirring and mixing, soaking for more than 12 hours, and drying in a drying oven at 45-50°C for more than 10 hours to prepare a biochar-nickel material containing nickel ions;

[0018] Step 2: Preparation of biochar-nickel loaded nano zero-valent iron material: Add an appropriate amount of biochar-nickel material to the nano zero-valent iron synthesis tank, add a certain amount of 1-1.5 mol / L FeSO4·7H2O solution to the nano zero-valent iron synthesis tank, stir thoroughly with the first stirrer for more than 30 minutes, titrate the same volume of 1.5-2 mol / L KBH4 solution, and then add FeSO4·7H2O solution at a rate of 50-60 drops / min. 2+ KBH4 solution was added dropwise to the mixed solution. After the addition was completed, the solution was stirred for more than 30 min to allow it to fully react. The prepared biochar-nickel material loaded with nano zero-valent iron material had the following reaction equation:

[0019] Fe 2+ + 2BH 4- + 6H2O → Fe 0 ↓+ 2B(OH)3+ 7H2↑;

[0020] Step 3: After the reaction is completed, the solid-liquid mixture is discharged into a solid-liquid separation tank for solid-liquid separation, and the liquid containing ferrous ions obtained after the solid-liquid separation is returned to the nano zero-valent iron synthesis tank for the next cycle of synthesis;

[0021] Step 4: discharge the biochar-nickel-loaded nano zero-valent iron material obtained after solid-liquid separation into the dense reaction zone of the wastewater reaction tank to react with the pyridine wastewater, and then react in the mixed reaction zone. The solid-liquid mixture after the reaction outputs clear water to the Fenton tank through the inclined tube sedimentation zone, and the composite nanomaterial falls onto the porous support layer;

[0022] Step 5. Finally, the pH value is adjusted to 3-3.5 in the acid adjustment zone, and the effluent flows to the Fenton zone, and H2O2 and pyridine wastewater are added in the Fenton zone for further redox reaction. After the reaction, it enters the alkali adjustment zone, and after the pH value is adjusted to 8-8.5, it flows into the sedimentation tank.

[0023] Preferably, the biochar material in step 1 is a porous carbon processed from organic waste, and the organic waste is selected from one or more of animal feces, animal bones, plant roots, sawdust, and wheat straw.

[0024] Preferably, the particle size of the biochar-nickel loaded nano zero-valent iron material in step 2 is 50-200 nm, and the weight ratio of biochar, nano nickel and nano zero-valent iron is 2:1:3.

[0025] Preferably, the pyridine wastewater in step 4 refers to organic wastewater generated during the production of pyridine derivative pesticide products, selected from one or more of clopyralid, tetrachloropyralid, pentachloropyridine and 2,3,5,6-tetrachloropyridinethiol chemical products.

[0026] Preferably, the sedimentation tank in step five is used to remove suspended matter in the water, and the suspended matter is one or more of Fe(OH)2, Fe(OH)3 and their complexes, and the sedimentation tank is selected from one of horizontal flow, vertical flow and radial flow.

[0027] The technical solution of the present invention has the following beneficial effects:

[0028] 1. Biochar-nickel material loaded with nano zero-valent iron can be produced quickly and continuously on site. After production, the composite nanomaterial does not need to be dried or washed, which solves the current problems of complicated preparation process of nano zero-valent iron, easy agglomeration of nanoparticles, and easy oxidation and inactivation during drying, storage, transportation and use.

[0029] 2. Use the micro-battery effect formed between nano zero-valent iron and biochar-nickel materials to enhance the strong redox performance of nano zero-valent iron. Using a stronger redox agent to modify nano zero-valent iron can quickly and effectively degrade and reduce it, reduce its biological toxicity, enhance the biodegradability of sewage, and achieve better pretreatment effects.

[0030] By using a new type of nano zero-valent iron synthetic material and utilizing the micro-battery effect formed between nano zero-valent iron and the load material, the strong redox properties of nano zero-valent iron are enhanced to degrade pyridine wastewater.

[0031] 3. Use nano zero-valent iron to react with wastewater to generate Fe 2+ , H202 is added to form the Fenton process, and the strong redox ability of hydroxyl radicals is used to further degrade pyridine substances.

[0032] 4. The main reaction adopts a partitioned tower contact reaction tower, which increases the contact between materials and wastewater, and is conducive to the use of gravity to separate materials and water quality, increase reaction efficiency and reduce floor space.

[0033] 5. After the biochar-nickel-loaded nano-zero-valent iron process + Fenton technology treatment, the pyridine derivatives that are difficult to degrade by general processes are degraded, the biological toxicity is reduced, and most of the undetectable COD parts are removed or decomposed. The biodegradability is increased, which is beneficial to the subsequent microbial biochemical reactions in the sewage treatment plant, preventing pyridine organic matter from being enriched in the activated sludge during long-term operation, and ensuring that the treatment meets the standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure of the present invention;

[0035] Figure 2 This is a schematic diagram of the structure of the nano zero-valent iron synthesis tank and the solid-liquid separation tank of the present invention;

[0036] Figure 3 This is a schematic diagram of the structure of the wastewater reaction tank of the present invention;

[0037] Figure 4 It is a schematic diagram of the structure of the Fenton tank and the sedimentation tank of the present invention. DETAILED DESCRIPTION

[0038] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0041] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the present invention, unless otherwise clearly specified and limited, a first feature is “on” or “below” a second feature.

[0043] “Under” may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature being “above”, “above”, and “above” the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being “under”, “below”, and “below” the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] Reference Figures 1 to 4 The present invention provides a composite nano zero-valent iron material pretreatment pyridine wastewater device, comprising: a nano zero-valent iron synthesis tank I, a solid-liquid separation tank II, a wastewater reaction tank III, a Fenton pool IV, and a sedimentation tank IV connected in sequence; the wastewater reaction tank III comprises an inclined tube sedimentation zone 11, a mixed reaction zone 12, a dense reaction zone 13, and a porous supporting layer 20 arranged in sequence; the Fenton pool comprises an acid adjustment zone 17, a Fenton reaction zone 18, and an alkali adjustment zone 19 connected in sequence.

[0045] The nano zero-valent iron synthesis tank I comprises a tank body, a ferrous ion dosing port 1, a potassium borohydride dosing port 2, a nitrogen inlet 3, a first gas discharge port 4, a first agitator 5, a first pressure gauge 6, a first loading and unloading port 7, a reflux port 8, a first water outlet 9, a first water outlet pipe 901, and a reflux pipe 801 arranged on the tank body;

[0046] The head of the first agitator 5 is placed on the top of the tank body, and the stirring part passes through the tank body and is placed inside it; the first gas exhaust port 4 is placed on one side of the first agitator 5, and the first pressure gauge 6 is placed on the other side of the first agitator; the ferrous ion dosing port 1, the potassium borohydride dosing port 2, and the nitrogen gas inlet 3 are all correspondingly arranged on one side of the tank body; the first loading and unloading port 7 and the reflux port 8 are all correspondingly arranged on the other side of the tank body; the first water outlet 9 is arranged at the bottom of the tank body; one end of the first water outlet pipe 901 is connected to the first water outlet 9, and the other end is connected to the solid-liquid separation tank II; one end of the reflux pipe 801 is connected to the reflux port 8, and the other end is connected to the solid-liquid separation tank II.

[0047] In this embodiment, when the nano zero-valent iron synthesis tank I is working, nitrogen is first discharged through the nitrogen inlet to isolate the influence of oxygen in the air, and then the biochar-nickel material is put into the tank through the loading and unloading port, and the ferrous ions are added to the tank from the dosing port through a peristaltic pump, and the mixture is fully mixed and stirred for more than 30 minutes, and then the prepared potassium borohydride is slowly added through the potassium borohydride dosing port to dissolve, and the reaction is more than 30 minutes after the addition is completed. The overall synthesis process is slowly discharged with nitrogen, and the agitator is stirred during the reaction process. After the reaction is completed, the solid-liquid mixture is discharged through the first water outlet 9 to the solid-liquid separation tank II, and is allowed to stand for more than 30 minutes. The solid composite nanomaterial enters the wastewater reaction tank III through the lower valve (set on the outlet pipe) to control, and the liquid containing ferrous ions is recycled and refluxed to the nano zero-valent iron synthesis tank I for the next cycle of synthesis.

[0048] The solid-liquid separation tank II includes a second tank body, and a liquid inlet 50, a second gas exhaust port 40, a second water outlet 95, a drain pipe 211 arranged on the second tank body, and a tee 35 arranged on the second water outlet 95; the second gas exhaust port 40 is arranged on the top of the second tank body; the liquid inlet 50 is arranged on the upper side of the second tank body; the second water outlet 95 is arranged at the bottom of the tank body; the other end of the first water outlet pipe 901 is connected to the liquid inlet 50 of the solid-liquid separation tank; the other end of the reflux pipe 801 is connected to one end of the tee 35 of the solid-liquid separation tank II; one end of the drain pipe 211 of the solid-liquid separation tank II is connected to the other end of the tee 35.

[0049] The wastewater reaction tank III includes a third tank body, and a spare water outlet 10, a third gas discharge port 400, a second pressure gauge 60, a third water outlet 90, a second water outlet pipe 902 connected to the third water outlet 90, two second loading and unloading ports 70, a reflux line 14, a composite zero-valent iron material discharge port 21, and a wastewater inlet 15 arranged on the third tank body; the spare water outlet 10, the third gas discharge port 400, and the second pressure gauge 60 are all arranged on the top of the tank body, the third gas discharge port 400 is arranged on one side of the spare water outlet, and the second pressure gauge 60 is arranged on the other side of the spare water outlet 10; the third water outlet 90 is arranged on the upper side of the tank body and is placed on the inclined tube sedimentation Zone 11; the composite zero-valent iron material discharge port 21 is connected to the other end of the drain pipe 211 of the solid-liquid separation tank II, and the composite zero-valent iron material discharge port 21 is opened on one side of the dense reaction zone 13; the two second loading and unloading ports 70 are opened on the other side of the dense reaction zone 13; one end of the reflux pipeline 14 is arranged on the other side of the dense reaction zone 13, and the other end is arranged below the porous supporting layer 20; the wastewater inlet 15 is arranged at the bottom of the tank body, and a drain port 16 is also arranged on one side of the wastewater inlet 15, and the water inlet end of the wastewater inlet 16 is also connected to a wastewater inlet pipe 151; valves are provided on the wastewater inlet pipe 151, the second outlet pipe 902, and the reflux pipe 801.

[0050] The porous supporting layer 20 is provided with a granular filler with a thickness of 20 cm, which can ensure uniform water distribution and ensure that part of the deposited composite nanomaterials fall on the granular filler and can also fully contact with the sewage. A return pipe is arranged under the porous supporting layer to prevent the accumulation of biological materials. The return device is properly opened to promote the water distribution of the granular filler.

[0051] The acid adjustment zone 17, the Fenton reaction zone 18, and the alkali adjustment zone 19 are respectively provided with a second agitator 501, a third agitator 502, and a fourth agitator 503; the pH range of the acid adjustment zone 17 is 3-3.5; the pH range of the alkali adjustment zone 19 is 8-8.5.

[0052] The present invention also provides a method for treating pyridine wastewater using a composite nano zero-valent iron material pretreatment device, comprising the following steps:

[0053] Step 1, preparing biochar-nickel material: soaking the biochar in an appropriate amount of NiCl6·6H2O solution, stirring and mixing, soaking for more than 12 hours, and drying in a drying oven at 45-50°C for more than 10 hours to prepare a biochar-nickel material containing nickel ions;

[0054] Step 2: Preparation of biochar-nickel loaded nano zero-valent iron material: Add an appropriate amount of biochar-nickel material to the nano zero-valent iron synthesis tank, add a certain amount of 1-1.5 mol / L FeSO4·7H2O solution to the nano zero-valent iron synthesis tank, stir thoroughly with the first stirrer for more than 30 minutes, titrate the same volume of 1.5-2 mol / L KBH4 solution, and then add FeSO4·7H2O solution at a rate of 50-60 drops / min. 2+ KBH4 solution was added dropwise to the mixed solution. After the addition was completed, the solution was stirred for more than 30 min to allow it to fully react. The prepared biochar-nickel material loaded with nano zero-valent iron material had the following reaction equation:

[0055] Fe 2+ + 2BH 4- + 6H2O → Fe 0 ↓+ 2B(OH)3+ 7H2↑;

[0056] Step 3: After the reaction is completed, the solid-liquid mixture is discharged into a solid-liquid separation tank for solid-liquid separation, and allowed to stand for more than 30 minutes. The liquid containing ferrous ions obtained after solid-liquid separation is refluxed to the nano zero-valent iron synthesis tank through the control of the lower valve for the next cycle of synthesis;

[0057] Step 4: discharge the biochar-nickel-loaded nano zero-valent iron material obtained after solid-liquid separation into the dense reaction zone of the wastewater reaction tank to react with the pyridine wastewater, and then react in the mixed reaction zone. The solid-liquid mixture after the reaction outputs clear water to the Fenton tank through the inclined tube sedimentation zone, and the composite nanomaterial falls onto the porous support layer;

[0058] Step 5. Finally, the pH value is adjusted to 3-3.5 in the acid adjustment zone, and the effluent flows to the Fenton zone. H2O2 is added in the Fenton zone, and the divalent iron generated by the nano zero-valent iron reaction is used for the Fenton reaction. The generated ·OH further undergoes redox reaction with the pyridine wastewater, and then enters the alkali adjustment zone. After the pH value is adjusted to 8-8.5, it flows into the sedimentation tank.

[0059] The biochar and nickel ions in step one are first stirred, mixed and dried, which is beneficial to increase the biochar-nickel material loading of nano zero-valent iron and evenly distribute it on the carrier surface, thereby enhancing the migration ability in the solution. The formed nickel-iron bimetallic can promote the nano zero-valent iron to lose electrons and promote the reaction with pyridine wastewater.

[0060] The biochar material in step 1 is a porous carbon made from organic waste, and the organic waste is selected from one or more of animal feces, animal bones, plant roots, wood chips, and wheat straw.

[0061] The particle size of the biochar-nickel loaded nano zero-valent iron material in step 2 is 50-200 nm, and the weight ratio of biochar, nano nickel and nano zero-valent iron is 2:1:3.

[0062] The biochar-nickel loaded nano zero-valent iron material, due to the large specific surface area of ​​the biochar and the micro-battery effect formed by Fe-C and Fe-Ni, reacts with organic matter to form a complex mechanism: (1) the adsorption effect of the biochar is conducive to the contact between the nano zero-valent iron on the surface of the biochar and its gaps and the organic matter in the wastewater; (2) the micro-battery effect of Fe-C and Fe-Ni promotes the transfer of electrons and enhances the degradation of organic matter.

[0063] The pyridine wastewater in step 4 refers to organic wastewater generated during the production of pyridine derivative pesticide products, selected from one or more of clopyralid, tetrachloropyralid, pentachloropyridine and 2,3,5,6-tetrachloropyridinethiol chemical products, and the inlet water needs to be acidic, neutral and alkaline, and needs to be adjusted to pH: 4.5-5.5. The pyridine wastewater enters from the lower wastewater inlet 15, and the solid-liquid mixture rises due to gravity solid-liquid separation, and the water outlet at the third outlet 90 can be guaranteed to be clear through the inclined tube sedimentation area 11.

[0064] The sedimentation tank in step five is used to remove suspended matter in the water, and the suspended matter is set to one or more of Fe(OH)2, Fe(OH)3 and their complexes. The sedimentation tank is selected from one of horizontal flow, vertical flow and radial flow. The supernatant flows into the biochemical section for biochemical treatment. The iron sludge discharge end is collected and connected to a separate sludge storage tank through a pipeline for recycling.

[0065] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, it can be seen from the above technical scheme that: (1) Biochar-nickel loaded nano zero-valent iron materials can be quickly produced on site, and can be produced and replenished at any time, thereby avoiding the problem of decreased activity caused by agglomeration and oxidation of nano zero-valent iron materials due to improper operation and storage; (2) The tower contact reaction tower utilizes the characteristics of material gravity in fluid mechanics to set up inclined tube sedimentation areas, mixed reaction areas, dense reaction areas and reflux pipelines, etc., thereby promoting the contact space between water and materials and intercepting materials in the reaction area; (3) Nano zero-valent iron generates Fe after reaction. 2+ , and further treatment is performed using Fenton technology. Biochar-nickel material loaded with nano zero-valent iron + Fenton technology pre-treats pyridine wastewater, degrades pyridine derivatives that are difficult to degrade in general processes, reduces biological toxicity, removes or decomposes most of the undetectable COD, improves biodegradability, and prevents pyridine organic matter from being enriched in activated sludge during long-term operation, ensuring that treatment meets standards.

[0066] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A composite nano zero-valent iron material pretreatment device for pyridine wastewater, characterized in that: include: A nano zero-valent iron synthesis tank, a solid-liquid separation tank, a wastewater reaction tank, a Fenton tank, and a sedimentation tank are sequentially connected; the wastewater reaction tank includes an inclined tube sedimentation zone, a mixed reaction zone, a dense reaction zone, and a porous support layer arranged in sequence; the Fenton tank includes an acid adjustment zone, a Fenton reaction zone, and an alkali adjustment zone that are sequentially connected; The nano zero-valent iron synthesis tank comprises a tank body, a ferrous ion dosing port, a potassium borohydride dosing port, a nitrogen inlet, a first gas discharge port, a first agitator, a first pressure gauge, a first loading and unloading port, a reflux port, a first water outlet, a first water outlet pipe, and a reflux pipe arranged on the tank body; the nano zero-valent iron synthesis tank is used for synthesizing biochar-nickel loaded nano zero-valent iron material; The head of the first agitator is placed on the top of the tank body, and the stirring part passes through the tank body and is placed inside it; the first gas discharge port is placed on one side of the first agitator, and the first pressure gauge is placed on the other side of the first agitator; the ferrous ion dosing port, potassium borohydride dosing port, and nitrogen gas inlet are all correspondingly arranged on one side of the tank body; the first loading and unloading port and the reflux port are correspondingly arranged on the other side of the tank body; the first water outlet is arranged at the bottom of the tank body; one end of the first water outlet pipe is connected to the first water outlet, and the other end is connected to the solid-liquid separation tank; one end of the reflux pipe is connected to the reflux port, and the other end is connected to the solid-liquid separation tank; The wastewater reaction tank comprises a third tank body, and a spare water outlet, a third gas discharge port, a second pressure gauge, a third water outlet, a second water outlet pipe connected to the third water outlet, two second loading and unloading ports, a reflux pipeline, a composite zero-valent iron material discharge port, and a wastewater inlet; the spare water outlet, the third gas discharge port, and the second pressure gauge are all arranged on the top of the tank body, the third gas discharge port is arranged on one side of the spare water outlet, and the second pressure gauge is arranged on the other side of the spare water outlet; the third water outlet is arranged It is placed on the upper side of the tank body and above the inclined tube sedimentation area; the composite zero-valent iron material discharge inlet is connected to the other end of the drain pipe of the solid-liquid separation tank, and the composite zero-valent iron material discharge inlet is opened on one side of the dense reaction area; the two second loading and unloading ports are opened on the other side of the dense reaction area; one end of the reflux pipeline is arranged on the other side of the dense reaction area, and the other end is arranged below the porous supporting layer; the wastewater inlet is arranged at the bottom of the tank body, and a drain port is also arranged on one side of the wastewater inlet, and the water inlet end of the wastewater inlet is also connected to a wastewater inlet pipe.

2. The composite nano zero-valent iron material pretreatment pyridine wastewater device according to claim 1, characterized in that: The solid-liquid separation tank includes a second tank body, and a liquid inlet, a second gas discharge port, a second water outlet, a drain pipe, and a tee provided on the second tank body; the second gas discharge port is provided on the top of the second tank body; the liquid inlet is provided on the upper side of the second tank body; the second water outlet is provided at the bottom of the tank body; the other end of the first water outlet pipe is connected to the liquid inlet of the solid-liquid separation tank; the other end of the reflux pipe is connected to one end of the tee of the solid-liquid separation tank; and one end of the drain pipe is connected to the other end of the tee.

3. The composite nano zero-valent iron material pretreatment pyridine wastewater device according to claim 1, characterized in that: The acid adjustment zone, Fenton reaction zone and alkali adjustment zone are each provided with a second agitator, a third agitator and a fourth agitator respectively; the pH range of the acid adjustment zone is 3-3.5; the pH range of the alkali adjustment zone is 8-8.

5.

4. The method for treating pyridine wastewater using a composite nano zero-valent iron material pretreatment device according to any one of claims 1 to 3, characterized in that: The steps include: Step 1, preparing biochar-nickel material: soaking the biochar in an appropriate amount of NiCl6·6H2O solution, stirring and mixing, soaking for more than 12 hours, and drying in a drying oven at 45-50°C for more than 10 hours to prepare a biochar-nickel material containing nickel ions; Step 2: Preparation of biochar-nickel loaded nano zero-valent iron material: Add an appropriate amount of biochar-nickel material to the nano zero-valent iron synthesis tank, add a certain amount of 1-1.5 mol / L FeSO4·7H2O solution to the nano zero-valent iron synthesis tank, stir thoroughly with the first stirrer for more than 30 minutes, titrate the same volume of 1.5-2 mol / L KBH4 solution, and then add FeSO4·7H2O solution at a rate of 50-60 drops / min. 2+ KBH4 solution was added dropwise to the mixed solution. After the addition was completed, the solution was stirred for more than 30 min to allow it to react fully to prepare the biochar-nickel material loaded with nano zero-valent iron material. The reaction equation is as follows: Fe 2+ + 2BH4 - + 6H2O → Fe 0 ↓+ 2B(OH)3 + 7H2↑; Step 3: After the reaction is completed, the solid-liquid mixture is discharged into a solid-liquid separation tank for solid-liquid separation, and the liquid containing ferrous ions obtained after the solid-liquid separation is returned to the nano zero-valent iron synthesis tank for the next cycle of synthesis; Step 4: discharge the biochar-nickel-loaded nano-zero-valent iron material obtained after solid-liquid separation into the dense reaction zone of the wastewater reaction tank to react with the pyridine wastewater, and then react in the mixed reaction zone. The solid-liquid mixture after the reaction outputs clear water to the Fenton tank through the inclined tube sedimentation zone, and the biochar-nickel-loaded nano-zero-valent iron material falls onto the porous support layer; Step 5: Finally, the pH value of the wastewater is adjusted to 3-3.5 in the acid adjustment zone, and the effluent flows to the Fenton zone, and H2O2 and pyridine wastewater are added in the Fenton zone for further redox reaction. After the reaction, the wastewater enters the alkali adjustment zone, and the pH value is adjusted to 8-8.5 before flowing into the sedimentation tank. The biochar material in step 1 is a porous carbon made from organic waste, and the organic waste is selected from one or more of animal feces, animal bones, plant roots, sawdust, and wheat straw; The particle size of the biochar-nickel loaded nano zero-valent iron material in step 2 is 50nm-200nm, and the weight ratio of biochar, nano nickel and nano zero-valent iron is 2:1:

3.

5. The processing method according to claim 4, characterized in that: The pyridine wastewater in step 4 refers to organic wastewater generated during the production process of pyridine derivative pesticide products.

6. The processing method according to claim 4, characterized in that: The sedimentation tank in step five is used to remove suspended matter in the water, and the suspended matter is one or more of Fe(OH)2, Fe(OH)3 and their complexes. The sedimentation tank is selected from one of horizontal flow, vertical flow and radial flow.

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