A method and system for the separation and treatment of wastewater by non-complete oxidation coupled polymerization

Abstract

The present invention provides a method and system for incompletely oxidizing, coupling, polymerizing and separating the treatment of wastewater. The method comprises the following steps: the industrial wastewater is acidified and then enters a pre-catalysis unit, a small amount of hydrogen peroxide is added, and a pre-catalytic oxidation reaction occurs under the action of a multi-metal doped FeOCl catalyst to obtain pre-catalytic wastewater; the pre-catalytic wastewater enters an incomplete oxidation unit, a ferrous salt and a large amount of hydrogen peroxide are added, under the action of a catalyst, a small amount of organic matter is mineralized and converted into CO2, and most of the organic matter is converted into intermediates and forms complexes to obtain incompletely oxidized wastewater; the incompletely oxidized wastewater is subjected to neutralization treatment to obtain neutralized wastewater; the neutralized wastewater enters a loading clarifier for treatment, a coagulant and a polymer carrier are added, and clear water is obtained through solid-liquid separation. The method for incompletely oxidizing, coupling, polymerizing and separating the treatment of wastewater provided by the present invention has good treatment effect, low operation cost and broad-spectrum removal effect on organic matter.

Description

Technical Field

[0001] The invention belongs to the field of advanced oxidation treatment of wastewater, and relates to a method and system for treating wastewater by incomplete oxidation coupling polymerization separation. Background Art

[0002] Industrial wastewater usually contains a large amount of refractory organic matter, and its deep purification has always been a problem. It is difficult to efficiently remove refractory organic matter through the biochemical treatment reaction of microorganisms. The use of advanced oxidation technology (such as ozone oxidation, Fenton oxidation, wet oxidation, etc.) is a more traditional and common technical means, which has been widely used in engineering.

[0003] The advanced oxidation technology is used to deeply purify the refractory organic matter in wastewater. The principle is to use the high oxidation potential of the oxidant to react with the organic matter to undergo a mineralization reaction, completely oxidizing the organic matter into CO2 for removal. This requires a large amount of oxidant and sufficient reaction time. In order to improve the efficiency of the oxidation reaction, various catalysts are usually added to the oxidation reaction to further improve the reaction efficiency and the utilization rate of the oxidant.

[0004] However, the existing advanced oxidation technology or catalytic oxidation technology has not changed the principle of advanced oxidation, that is, to completely oxidize organic matter into CO2 for removal, which leads to the following deficiencies: First, the existing technology requires the consumption of a large amount of oxidants and sufficient reaction time; second, the reaction conditions of the existing technology are relatively harsh. For example, the Fenton reaction needs to be carried out under strong acidic conditions (pH 2-4), and wet oxidation needs to be carried out under high temperature (120~320℃) and high pressure (0.5~20MPa). In addition, the existing technology is selective in the removal effect of different organic matter. For example, oxidants such as ozone and Fenton are difficult to achieve mineralization removal for many phenols, amines, and complex long-chain organic matter due to their insufficient oxidation potential. The above deficiencies lead to the defects of poor treatment effect and high operating cost in the existing advanced oxidation technology.

[0005] Therefore, developing a wastewater treatment method with better treatment effect and lower operating cost has become a research direction in this field. Summary of the invention

[0006] The invention provides a wastewater non-complete oxidation coupled polymerization separation treatment method, which has the technical effects of good treatment effect and low operating cost.

[0007] The present invention also provides a wastewater non-complete oxidation coupled polymerization separation treatment system, which has the technical effects of simple structure and low operating cost.

[0008] The present invention provides a method for treating wastewater by incomplete oxidation coupled polymerization separation, wherein the method is performed using a system for treating wastewater by incomplete oxidation coupled polymerization separation;

[0009] The non-complete oxidation coupled polymerization separation treatment system for wastewater comprises a pre-catalytic unit, a non-complete oxidation unit, a neutralization unit, and a loading clarification separation unit which are connected in sequence;

[0010] The pre-catalytic unit and the incomplete oxidation unit are provided with a multi-metal doped FeOCl catalyst;

[0011] The non-complete oxidation coupled polymerization separation treatment method for wastewater comprises the following steps:

[0012] Allowing industrial wastewater with a pH value of 5.0-5.5 to enter a pre-catalytic unit, adding a first dosage of hydrogen peroxide to the industrial wastewater, and performing a pre-catalytic treatment on the industrial wastewater to obtain pre-catalytic wastewater;

[0013] The pre-catalytic wastewater is allowed to enter the incomplete oxidation unit, ferrous salt and a second dosage of hydrogen peroxide are added to the pre-catalytic wastewater, and the pre-catalytic wastewater is subjected to incomplete oxidation treatment to obtain incompletely oxidized wastewater;

[0014] Allowing the incompletely oxidized wastewater to enter the neutralization unit, performing a neutralization treatment on the incompletely oxidized wastewater to make the incompletely oxidized wastewater neutral, and obtaining neutralized wastewater;

[0015] Allowing the neutralized wastewater to enter the loading, clarifying and separating unit, adding a coagulant and a polymer carrier to the neutralized wastewater, and performing loading, clarifying and separating treatment on the neutralized wastewater to obtain clean water;

[0016] The first dosage accounts for 30-50% of the sum of the first dosage and the second dosage;

[0017] The second dosage accounts for 50-70% of the sum of the first dosage and the second dosage;

[0018] The treatment environment pH of the pre-catalytic treatment is 5.0-5.5, and the hydraulic retention time is 2-5min;

[0019] The treatment environment pH of the incomplete oxidation treatment is 4-5, the redox potential is 200-400mV, and the hydraulic retention time is 10-30min;

[0020] The multi-metal doped FeOCl catalyst comprises a low-valent metal catalyst, a high-valent metal catalyst, and a carrier;

[0021] The low-valent metal catalyst is FeOCl doped with an X element, wherein the X element is selected from at least one of Cu, Mn, and Ni;

[0022] The high-valent metal catalyst is selected from at least one of MoS2 and WS2;

[0023] The carrier is selected from at least one of zeolite, volcanic rock and activated carbon.

[0024] In the above-mentioned non-complete oxidation coupled polymerization separation treatment method for wastewater, in the pre-catalytic treatment, the dosage of hydrogen peroxide is 30-50 mg / L.

[0025] As described above, the non-complete oxidation coupled polymerization separation treatment method for wastewater, wherein, in the non-complete oxidation treatment, the ferrous salt is ferrous sulfate, the dosage is 60-120 mg / L, and the dosage of hydrogen peroxide is 70-100 mg / L.

[0026] The non-complete oxidation coupled polymerization separation and treatment method for wastewater as described above, wherein the multi-metal doped FeOCl catalyst is prepared using a method comprising the following process:

[0027] contacting an aqueous solution including iron ions and element X with a carrier to obtain a first intermediate catalyst;

[0028] performing a first calcination treatment on the first intermediate catalyst to obtain a second intermediate catalyst;

[0029] contacting the second intermediate catalyst with the high-valent metal catalyst to obtain a third intermediate catalyst;

[0030] The third intermediate catalyst is subjected to a second calcination treatment to obtain the multi-metal doped FeOCl catalyst.

[0031] The above-mentioned non-complete oxidation coupled polymerization separation and treatment method for wastewater, wherein the particle size of the polymer carrier is 0.3-0.8 mm, and the density is 3-5 g / cm 3 The dosage is 5-10% of the volume of the neutralized wastewater.

[0032] In the above-mentioned non-complete oxidation coupled polymerization separation treatment method for wastewater, the hydraulic retention time of the loading clarification separation treatment is 30-40 minutes.

[0033] The above-mentioned wastewater non-complete oxidation coupled polymerization separation treatment method further comprises:

[0034] The mineralization degree of industrial wastewater was calculated using Equation 1;

[0035] Y=k1k2(X1-X2) / (C1-C2)+b Formula 1;

[0036] in,

[0037] Y is the mineralization degree of industrial wastewater; 0<Y<1;

[0038] X1 is the COD concentration of industrial wastewater, mg / L;

[0039] X2 is the COD concentration of clean water, mg / L;

[0040] C1 is the CO2 concentration of pre-catalytic wastewater, mg / L;

[0041] C2 is the CO2 concentration of the incompletely oxidized wastewater, mg / L;

[0042] k1 is the conversion coefficient, 0<k1<1;

[0043] k2 is the correction coefficient, 1.1<k2<1.5;

[0044] b is the loss coefficient, 0<b<0.3;

[0045] When Y>0.5, the redox potential of the incomplete oxidation treatment is reduced.

[0046] In the above-mentioned method for separation and treatment of wastewater by non-complete oxidation coupled polymerization, the treatment pressure of the pre-catalytic treatment is 0.05-0.1Mpa.

[0047] The present invention also provides a wastewater non-complete oxidation coupled polymerization separation treatment system, which is used to perform any of the above wastewater non-complete oxidation coupled polymerization separation treatment methods, and the system comprises a pre-catalytic unit, a non-complete oxidation unit, a neutralization unit, and a loading clarification separation unit connected in sequence;

[0048] The pre-catalytic unit and the incomplete oxidation unit are provided with a multi-metal doped FeOCl catalyst.

[0049] The wastewater incomplete oxidation coupled polymerization separation treatment system as described above, wherein the incomplete oxidation unit is provided with a carbon dioxide sensor; and / or,

[0050] The incomplete oxidation unit further includes a circulating water pump, and a circulating outlet of the incomplete oxidation unit is connected to a circulating inlet of the incomplete oxidation unit through the circulating water pump.

[0051] The non-complete oxidation coupled polymerization separation treatment method for wastewater provided by the present invention realizes the removal of most organic matter by polymerization separation on the basis of having a good treatment effect through the method of non-complete oxidation coupled polymerization separation, which saves a large amount of oxidant consumption compared to the complete oxidation removal of organic matter; in addition, compared with the prior art, the reaction conditions provided by the present invention are milder (such as pH control), saving a large amount of acid adjustment agents and alkali neutralization agents; the complete oxidation technology has a certain selectivity for the oxidation removal of difficult-to-degrade organic matter with different potentials and different chemical bonds. The present invention catalytically oxidizes the difficult-to-degrade organic matter into intermediates, and then removes them through polymerization separation, which has the advantage of wider spectrum removal. Therefore, the non-complete oxidation coupled polymerization separation treatment method for wastewater provided by the present invention has the technical effects of good treatment effect, low operating cost, and broad spectrum of organic matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced one by one below. Obviously, the drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0053] Figure 1 A schematic diagram of the structure of the non-complete oxidation coupled polymerization separation treatment system for wastewater provided by the present invention;

[0054] Figure 2 This is a device diagram of the non-complete oxidation coupled polymerization separation treatment system for wastewater provided by the present invention;

[0055] Figure 3 This is the Fourier infrared spectrum of the polymerized precipitate solid phase material obtained in Example 1.

[0056] Description of reference numerals:

[0057] 1- pre-catalytic unit;

[0058] 2-non-complete oxidation unit;

[0059] 3-Neutralization unit;

[0060] 4- Loading clarification separation unit;

[0061] 101-precatalytic reactor;

[0062] 201- non-complete oxidation reactor;

[0063] 301-neutralization reactor;

[0064] 401-loading clarification reactor;

[0065] 402- Inclined plate sedimentation tank. DETAILED DESCRIPTION

[0066] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0067] The existing advanced oxidation technology aims to completely oxidize organic matter in wastewater, so it requires harsh reaction conditions and a large amount of oxidants, resulting in high treatment costs. In addition, the existing technology is difficult to completely mineralize and remove phenols, amines, and complex long-chain organic matter because these organic matter has high potential and functional groups that are difficult to degrade. Therefore, if some organic matter can be removed by non-oxidative means, the treatment cost can be reduced while ensuring the treatment effect.

[0068] Based on this, the first aspect of the present invention protects a method for the separation and treatment of wastewater by non-complete oxidation coupled polymerization, which is performed using a system for the separation and treatment of wastewater by non-complete oxidation coupled polymerization;

[0069] The incomplete oxidation coupled polymerization separation treatment system for wastewater comprises a pre-catalytic unit, an incomplete oxidation unit, a neutralization unit, and a loading clarification separation unit which are connected in sequence;

[0070] The pre-catalytic unit and the incomplete oxidation unit are provided with a multi-metal doped FeOCl catalyst;

[0071] The non-complete oxidation coupled polymerization separation treatment method for wastewater comprises the following steps:

[0072] Allowing industrial wastewater to enter a pre-catalytic unit, adding a first dosage of hydrogen peroxide to the industrial wastewater, and performing pre-catalytic treatment on the industrial wastewater to obtain pre-catalytic wastewater;

[0073] The pre-catalytic wastewater is allowed to enter a non-complete oxidation unit, ferrous salt and a second dosage of hydrogen peroxide are added to the pre-catalytic wastewater, and the pre-catalytic wastewater is subjected to non-complete oxidation treatment to obtain non-completely oxidized wastewater;

[0074] The incompletely oxidized wastewater is allowed to enter a neutralization unit, and the incompletely oxidized wastewater is subjected to a neutralization treatment to make the incompletely oxidized wastewater neutral, thereby obtaining neutralized wastewater;

[0075] The neutralized wastewater is allowed to enter a loading clarification separation unit, a coagulant and a polymer carrier are added to the neutralized wastewater, and the neutralized wastewater is subjected to loading clarification separation treatment to obtain clean water;

[0076] The first dosage accounts for 30-50% of the sum of the first dosage and the second dosage;

[0077] The second dosage accounts for 50-70% of the sum of the first dosage and the second dosage;

[0078] The pH of the treatment environment for pre-catalytic treatment is 5.0-5.5, and the hydraulic retention time is 2-5min;

[0079] The treatment environment pH of the non-complete oxidation treatment is 4-5, the redox potential is 200-400mV, and the hydraulic retention time is 20-40min;

[0080] The multi-metal doped FeOCl catalyst includes a low-valent metal catalyst, a high-valent metal catalyst, and a carrier;

[0081] The low-valent metal catalyst is FeOCl doped with an X element, wherein the X element is selected from at least one of Cu, Mn, and Ni;

[0082] The high-valent metal catalyst is selected from at least one of MoS2 and WS2;

[0083] The carrier is selected from at least one of zeolite, volcanic rock and activated carbon.

[0084] In the above process, industrial wastewater is wastewater containing organic pollutants. The present invention does not limit the source of industrial wastewater. In one embodiment, the industrial wastewater can come from the effluent of the secondary sedimentation tank of a sewage treatment plant.

[0085] like Figure 1 As shown, the non-complete oxidation coupled polymerization separation treatment system for wastewater includes 1-pre-catalytic unit, 2-non-complete oxidation unit, 3-neutralization unit, and 4-loading clarification separation unit which are connected in sequence. Among them, 1-pre-catalytic unit is used to perform pre-catalytic treatment, 2-non-complete oxidation unit is used to perform non-complete oxidation treatment, 3-neutralization unit is used to perform neutralization treatment, 4-loading clarification separation unit is used to perform loading clarification separation treatment, and the system is a continuous flow operation. The present invention does not limit the specific equipment selection of the above units, and reaction vessels that meet various treatment requirements in the field can be used.

[0086] Both the 1-pre-catalytic unit and the 2-incomplete oxidation unit are equipped with a multi-metal doped FeOCl catalyst. Specifically, in the 1-pre-catalytic unit, the multi-metal doped FeOCl catalyst has a particle size of 5-8 mm and is installed in the 1-pre-catalytic unit as a fixed bed using a mesh box package to prevent catalyst loss. When industrial wastewater enters the 1-pre-catalytic unit, due to the impact of water flow and pressure, the catalyst particles are in a fluidized state in the fixed bed and are in full contact with the industrial wastewater to produce a catalytic reaction. In the 2-incomplete oxidation unit, the multi-metal doped FeOCl catalyst has a particle size of less than 1 mm.

[0087] The specific process of the non-complete oxidation coupling polymerization separation treatment method for wastewater provided by the present invention is as follows: after the pH value of industrial wastewater is adjusted to 5.0-5.5 using an acidic agent such as sulfuric acid, it enters a 1-pre-catalytic unit. A first dosage of hydrogen peroxide is added to the industrial wastewater to perform pre-catalytic treatment on the industrial wastewater. In this process, the fixed multi-metal doped FeOCl catalyst releases multi-metal ions, and FeOCl forms Fe with multiple catalytic sites. 2+ Specifically, the fixed multi-metal doped FeOCl catalyst releases multi-metal ions, and FeOCl forms multiple catalytic sites of Fe 2+ , catalyzes hydrogen peroxide to form hydroxyl radicals. 2+ Both ions and hydrogen peroxide are limited, and the reaction pH is controlled to be mild (5.0-5.5), so that the organic matter in the wastewater is weakly catalytically oxidized, some organic matter is partially degraded, and some organic intermediates are obtained. Industrial wastewater is treated with catalysis to obtain pre-catalytic wastewater.

[0088] The pre-catalytic wastewater enters the 2-non-complete oxidation unit, and ferrous salt and a second amount of hydrogen peroxide are added to perform non-complete oxidation treatment on the pre-catalytic wastewater to obtain non-completely oxidized wastewater.

[0089] In this process, under the action of fluidized multi-metal doped FeOCl catalyst, ferrous salts, multi-metal ions and FeOCl react with hydrogen peroxide together, and a large amount of Fe 2+ It promotes the strong catalytic oxidation reaction of hydrogen peroxide, promotes the mineralization reaction of some organic matter into carbon dioxide, and some more difficult to degrade organic matter is converted into small molecular organic intermediates under its strong action; and based on the formation of multiple catalytic sites based on FeOCl, under the action of multi-metal ions, some organic matter is further converted into intermediates, and forms complexes with multi-metal ions without completing mineralization, resulting in incompletely oxidized wastewater. In this process, on the one hand, conventional ferrous salts are added to form free Fe 2+ions, catalyze the reaction with hydrogen peroxide to form hydroxyl radicals, thereby achieving the oxidation and degradation of organic matter. Therefore, the redox potential of some easily oxidized and degraded organic matter is relatively low, and the organic matter is converted into CO2 and H2O through complete oxidation to achieve mineralization removal; on the other hand, due to the action of the multi-metal doped FeOCl catalyst, the Fe and Cl connected to O provide more reaction potentials. Under the action of multi-metal ions, it simultaneously adsorbs and oxidizes the difficult-to-degrade organic matter and hydrogen peroxide, and more directly undergoes redox reaction, thereby achieving incomplete oxidation reaction of most difficult-to-degrade organic matter, such as oxidizing the difficult-to-degrade macromolecular organic matter into intermediate products such as molecular carboxylation and aldehyde formation, rather than complete mineralization into CO2 and H2O. The intermediate products such as molecular carboxylation and aldehyde formation are further enriched by forming complexes with metal salts, which is more conducive to subsequent polymerization and separation treatment. Therefore, in the above process, the mineralization oxidation and incomplete oxidation reaction of organic matter occur simultaneously in the 2-non-complete oxidation unit.

[0090] In the above process, the first dosage of hydrogen peroxide accounts for 30-50% of the sum of the first dosage and the second dosage; the second dosage of hydrogen peroxide accounts for 50-70% of the sum of the first dosage and the second dosage. The sum of the first dosage and the second dosage is the total dosage of hydrogen peroxide in the system, that is, a small amount of hydrogen peroxide is added in the pre-catalytic treatment, and the remaining majority of hydrogen peroxide is added in the incomplete oxidation treatment. The above dosage ratio can make the pre-oxidation treatment and the incomplete oxidation treatment more efficient.

[0091] Subsequently, the incompletely oxidized wastewater enters the 3-neutralization unit, and NaOH or Ca(OH)2 is added to the incompletely oxidized wastewater to neutralize the incompletely oxidized wastewater to make it neutral, thereby obtaining neutralized wastewater.

[0092] The neutralized wastewater enters the 4-loading clarification separation unit, into which coagulants and polymer carriers are added for loading clarification separation treatment. Among them, coagulants generally include Al 3+ , Fe 3+ Coagulants of high-valent metals such as PAC (polyaluminium chloride); polymer carriers refer to substances that have the function of forming condensation nuclei in coagulation reactions, such as quartz sand or mineral sand with a certain strength and wear resistance.

[0093] During the loading clarification separation process, on the one hand, the organic intermediates and multi-metal complexes formed by the incomplete oxidation treatment further complex and enrich with the metal salt coagulants and metal ions on the surface of the polymer carrier to form more stable suspended flocs that promote co-precipitation through the carrier effect; on the other hand, due to the Al 3+ , Fe 3+Coagulants such as these coagulants coagulate and precipitate suspended solids, colloids, and enriched organic pollutants in non-completely oxidized wastewater through traditional coagulation and sedimentation.

[0094] Loading clarification separation treatment includes separation treatment. During the separation treatment process, the multi-metal complex enriched flocs, suspended matter, colloids and enriched organic matter formed by coagulation and polymerization reactions are quickly precipitated under the action of carrier condensation nuclei, achieving mud-water separation and obtaining a clean water discharge system, thereby achieving the precipitation, separation and removal of organic pollutants.

[0095] In short, the loaded clarification separation treatment adds coagulants and polymer carriers to the neutralized wastewater. 3+ or Fe 3+ Coagulation reaction occurs, and the organic intermediates further react with Al 3+ or Fe 3+ The high-valent polymetallic substances undergo polymerization reactions to form suspended sludge such as colloids, precipitates, and complexes, which then coagulate under the action of the carrier to achieve polymerization and precipitation of the suspended sludge, thereby achieving mud-water separation and obtaining treated clean water, also known as clear water.

[0096] More specifically, the pH of the pre-catalytic treatment can be controlled to be 5.0-5.5, and the hydraulic retention time is 2-5min. The reason why the pH of the pre-catalytic treatment needs to be controlled to be 5.0-5.5 is that too high a pH is not conducive to the occurrence of organic matter cracking reactions, which is not conducive to polymerization reactions, while too low a pH will lead to a stronger catalytic oxidation reaction, resulting in a complete oxidation reaction of the organic matter, which is not conducive to subsequent polymerization reactions, and causes an increase in the amount of oxidizing agents and neutralizing agents, thereby increasing treatment costs. Controlling the hydraulic retention time of the pre-catalytic treatment to be 2-5min can avoid the complete oxidation reaction of easily degradable organic matter, resulting in an increase in the amount of oxidizing agents, which is not conducive to subsequent polymerization reactions. The pre-catalytic treatment pH can be 5.0-5.5 by adding sulfuric acid to industrial wastewater.

[0097] In addition, the pH of the incomplete oxidation treatment can be controlled to be 4-5, the redox potential to be 200-400mV, the hydraulic retention time to be 10-30min, and the catalyst in the incomplete oxidation treatment is in a fluidized state, and the dosage is 2-5-10% of the volume of the incomplete oxidation unit. Controlling the pH of the treatment environment of the incomplete oxidation treatment to be 4-5 and the redox potential to be 200-400mV is conducive to controlling mineralization and incomplete oxidation. Too low pH and too high redox potential are conducive to the occurrence of complete mineralization, which is not conducive to the formation of intermediate products by incomplete oxidation. Therefore, a large amount of oxidizing agents (hydrogen peroxide) and acid regulating agents (such as sulfuric acid) are consumed, resulting in increased treatment costs; too high pH and too low ORP are not conducive to the occurrence of oxidation reactions, the cracking of organic matter, and the formation of intermediate products, thereby reducing the treatment effect. The redox potential can be adjusted using common means in the art. For example, adjusting the dosage of hydrogen peroxide can affect the redox potential. The higher the amount of hydrogen peroxide added, the higher the redox potential.

[0098] In addition, controlling the hydraulic retention time of the incomplete oxidation treatment to 10-30 minutes can ensure the effectiveness of the reaction. Too short a reaction time is not enough for a thorough reaction, and too long a reaction time is not conducive to the stability of the intermediate product. It is easy to cause further mineralization of the organic intermediate due to too long a hydraulic retention time, and then the treatment cost increases due to excessive consumption of hydrogen peroxide.

[0099] The multi-metal doped FeOCl catalyst includes a low-valent metal catalyst, a high-valent metal catalyst, and a carrier;

[0100] The low-valent metal catalyst is FeOCl doped with an X element, wherein the X element is selected from at least one of Cu, Mn, and Ni;

[0101] The high-valent metal catalyst is selected from at least one of MoS2 and WS2;

[0102] The carrier is selected from at least one of zeolite, volcanic rock and activated carbon.

[0103] The present invention does not limit the molar ratio of the Fe element to the X element in the low-valent metal catalyst, as long as the low-valent metal catalyst is FeOCl doped with the X element.

[0104] In the 1-pre-catalytic unit, a fixed bed is used to install large particle catalyst with a particle size of 5 to 8 mm and a specific surface area of ​​≥200m 2 / g, using mesh cage packaging as a fixed bed installed in the 1-pre-catalytic unit. When industrial wastewater passes through the 1-pre-catalytic unit, due to the impact of water flow and pressure, the catalyst particles are in a fluidized state in the fixed bed and fully contact with the wastewater to cause a catalytic reaction.

[0105] The multi-metal doped FeOCl catalyst comprises a low-valent metal catalyst, a high-valent metal catalyst, and a carrier, wherein the low-valent metal catalyst is FeOCl doped with an X element, that is, the X element at least partially replaces the iron element in FeOCl to obtain a low-valent metal catalyst. The X element is selected from at least one of Cu, Mn, and Ni, that is, the X element can be selected from any one of Cu, Mn, and Ni alone, or can be selected from a plurality of Cu, Mn, and Ni. For example, the X element can be Cu, Mn, or Mn, Ni, or Cu, Mn, and Ni. The present invention does not limit the molar ratio of the Fe element to the X element in the low-valent metal catalyst, as long as the low-valent metal catalyst is FeOCl doped with the X element.

[0106] The high-valent metal catalyst is selected from at least one of MoS2 and WS2. That is, the high-valent metal catalyst can be selected from any one of MoS2 and WS2, or can include both MoS2 and WS2.

[0107] The present invention does not impose any limitation on the mass ratio or molar ratio of the low-valent metal catalyst to the high-valent metal catalyst, as long as the requirement of including both the low-valent metal catalyst and the high-valent metal catalyst is met.

[0108] In the 2-non-complete oxidation unit, a small particle catalyst is directly added, completely mixed with the wastewater in the 2-non-complete oxidation unit, and a fluidized state is formed through a circulating water pump, thereby ensuring full contact and mixing with the reagent and the wastewater. The present invention does not limit the size of the carrier. In one embodiment, in order to better form a fluidized state, the carrier particle size can be controlled to be 0.8 to 1.2 mm, and the specific surface area ≥300 m 2 / g.

[0109] In the multi-metal doped FeOCl catalyst, both the low-valent metal catalyst and the high-valent metal catalyst are in contact with the carrier. More specifically, the low-valent metal catalyst and the high-valent metal catalyst are combined with each other and grown and loaded on the surface of the carrier to form an integrated catalyst. The present invention does not limit the mass ratio of the low-valent metal catalyst, the high-valent metal catalyst and the carrier, and the requirement of including the low-valent metal catalyst, the high-valent metal catalyst and the carrier at the same time is sufficient.

[0110] The present invention does not limit the specific method of loading the low-valent metal catalyst and the high-valent metal catalyst on the surface of the carrier, and common methods in the art can be used. In one embodiment, the low-valent metal catalyst and the high-valent metal catalyst can be brought into contact with the carrier, and the low-valent metal catalyst is in situ grown on the surface of the carrier, while the carrier adsorbs the high-valent metal catalyst and is in situ deposited on the surface of the low-valent metal catalyst, and calcined, so that the low-valent metal catalyst and the high-valent metal catalyst are combined through new chemical bonds, thereby forming the multi-metal doped FeOCl catalyst.

[0111] Multi-metal doped FeOCl catalyst plays an important role in the occurrence of incomplete oxidation reactions. Multi-metal doped FeOCl catalyst Multi-metal doped FeOCl catalyst The multi-metal doped FeOCl catalyst is loaded on a carrier by the simultaneous growth of a low-valent metal catalyst and a high-valent metal catalyst, which increases the active centers on the catalyst surface while improving the dual-path electron circulation inside and outside the crystal structure of the FeOCl catalyst, greatly improving the Fe(II) / Fe(II) circulation rate, thereby obtaining a higher hydrogen peroxide catalytic efficiency; at the same time, the O on the FeOCl surface connects the Fe and Cl sites, which can directly undergo neighboring adsorption and activation for pollutants and hydrogen peroxide, allowing them to directly undergo redox reactions and promote the cracking of organic matter.

[0112] Compared with the prior art, the wastewater treatment method provided by the present invention has the following advantages:

[0113] First, the wastewater treatment method provided by the present invention achieves the effect of removing 60-80% of organic matter through polymerization separation and 20-40% of organic matter through complete mineralization through the means of non-complete oxidation coupled polymerization separation. Since complete mineralization removal requires the consumption of larger oxidants and more stringent reaction conditions, the present invention can save a large amount of oxidants, such as up to 50% of hydrogen peroxide reagents, thereby having a lower treatment cost.

[0114] Second, the wastewater treatment method provided by the present invention also achieves milder reaction conditions. For example, the treatment environment of the non-complete oxidation treatment is controlled to be 4-5, which is milder than the traditional Fenton reaction (pH 2-4), thereby saving a large amount of acid adjustment agents and alkali neutralization agents. The total reagent cost can be saved by more than 40% compared with the traditional Fenton process.

[0115] Third, the wastewater treatment method provided by the present invention avoids the large amount of CO2 produced by the complete mineralization reaction, directly reduces CO2 emissions by 60-70%, and achieves carbon emission reduction; at the same time, due to the substantial reduction of CO2 during the reaction process and the condensation and polymerization of the polymer carrier, a good precipitation separation effect can be achieved without degassing it, thereby eliminating the need to use the degassing treatment commonly used in the prior art.

[0116] In one embodiment, in the pre-catalytic treatment, the dosage of hydrogen peroxide is 30-50 mg / L, and the dosage can be coordinated with the pH and hydraulic retention time to cause an appropriate degree of cracking of organic matter in the industrial wastewater to prepare for subsequent treatment.

[0117] Furthermore, in the incomplete oxidation treatment, the ferrous salt is ferrous sulfate, the dosage is 60-120 mg / L, and the dosage of hydrogen peroxide is 70-100 mg / L. The appropriate dosage of ferrous salt and hydrogen peroxide can be coordinated with pH and hydraulic retention time to make the organic matter in the pre-catalytic wastewater more effectively undergo mineralization oxidation and incomplete oxidation reactions simultaneously, avoiding the occurrence of excessive mineralization or incomplete reaction.

[0118] In one embodiment, the multi-metal doped FeOCl catalyst is prepared using a method comprising the following process:

[0119] contacting an aqueous solution including iron ions and element X with a carrier to obtain a first intermediate catalyst;

[0120] performing a first calcination treatment on the first intermediate catalyst to obtain a second intermediate catalyst;

[0121] contacting the second intermediate with a high-valent metal catalyst to obtain a third intermediate catalyst;

[0122] The third intermediate catalyst is subjected to a second calcination treatment to obtain a multi-metal doped FeOCl catalyst.

[0123] The aqueous solution including iron ions and element X is an aqueous solution in which iron ions and a compound of element X are dissolved. The present invention does not limit the compound of element X, and commonly used compounds in the art can be used, for example, copper chloride, manganese chloride, nickel chloride, copper sulfate, manganese sulfate, nickel sulfate, copper nitrate, manganese nitrate, nickel nitrate, copper acetate, manganese acetate, nickel acetate, and the iron ions can come from ferric chloride, ferric sulfate, ferric nitrate, ferric acetate, etc.

[0124] It is understood that the type of the X element in the aqueous solution including iron ions and the X element corresponds to the X element contained in the low-valent metal catalyst to be produced. For example, if the X element contained in the low-valent metal catalyst to be produced is Cu, Mn, or Ni, the aqueous solution including iron ions and the X element should include the above metal elements at the same time.

[0125] The present invention does not limit the specific process of contacting the aqueous solution including iron ions and element X with the carrier, as long as the requirements for contact between the two are met. In one embodiment, the carrier can be added to the aqueous solution including iron ions and element X to mix the two. In the above process, the iron ions and element X are adsorbed on the surface of the carrier. The above mixed system is subjected to solid-liquid separation, and the solid phase material obtained is the first intermediate catalyst. The first intermediate catalyst is subjected to a first calcination treatment, and the iron ions and element X adsorbed on the surface of the carrier are converted into a low-valent metal catalyst. The substance composed of the low-valent metal catalyst and the carrier is the second intermediate catalyst.

[0126] Subsequently, the second intermediate is contacted with a high-valent metal catalyst to obtain a third intermediate catalyst. The present invention does not limit the contact method of the second intermediate and the high-valent metal catalyst. In one embodiment, the two can be dispersed in water at the same time and contacted. In this process, the high-valent metal catalyst is adsorbed on the surface of the second intermediate catalyst to obtain a third intermediate catalyst. The third intermediate catalyst is subjected to a second calcination treatment to obtain a multi-metal doped FeOCl catalyst.

[0127] It is understood that since both the second intermediate catalyst and the high-valent metal catalyst are solids insoluble in water, after the contact process is completed, the reaction system is further subjected to a solid-liquid separation treatment with a specific precision, such as filtration or centrifugation, to separate the third intermediate catalyst from the unreacted high-valent metal catalyst. The filtration precision can be determined according to the carrier particle size. For example, when the carrier particle size is 3-5 mm, the filtration precision can be controlled within the above range to achieve effective separation between the third intermediate catalyst and the unreacted high-valent metal catalyst.

[0128] The first calcination treatment allows the iron ions and the X element to form a low-valent metal catalyst on the surface of the carrier and to bind more tightly to the carrier, and the second calcination treatment allows the high-valent metal catalyst on the surface of the third intermediate catalyst to bind more tightly to the low-valent metal catalyst and the carrier. The present invention does not limit the specific treatment conditions of the first calcination treatment and the second calcination treatment. In one embodiment, the above calcination treatments can be carried out in air, the treatment temperature is 150-300°C, and the treatment time is 1-5h.

[0129] It is understandable that before calcination, in order to volatilize the moisture in the treated object, in one embodiment, before the first calcination and the second calcination, the first intermediate catalyst and the third intermediate catalyst may be dried in an environment of 80-120° C. for 12-24 hours.

[0130] In one embodiment, the dosage of the coagulant can be controlled to be 5-10 mg / L (based on the effective aluminum or iron content in the coagulant), that is, a coagulant equivalent to 5-10 g Al2O3 is added to each cubic meter of neutralized wastewater. Furthermore, the particle size of the polymer carrier can be controlled to be 0.3-0.8 mm, and the density to be 3-5 g / cm 3 The dosage is 5-10% of the volume of the neutralized wastewater. The polymer carrier with the above characteristics is more likely to form condensation nuclei in the polymerization and coagulation reactions, and has the effect of polymerization and coprecipitation on the fine flocs formed by incomplete oxidation, which is more conducive to precipitation separation.

[0131] Furthermore, the hydraulic retention time of the loading clarification separation treatment can be controlled to be 30-40 minutes. The above hydraulic retention time is conducive to the effective formation of flocs.

[0132] In one embodiment, the present invention provides the use of formula 1 to calculate the degree of mineralization;

[0133] Y=k1k2(X1-X2) / (C1-C2)+b Formula 1;

[0134] in,

[0135] Y is the degree of mineralization; 0<Y<1;

[0136] X1 is the COD concentration of industrial wastewater, mg / L;

[0137] X2 is the COD concentration of clean water, mg / L;

[0138] C1 is the CO2 concentration of pre-catalytic wastewater, mg / L;

[0139] C2 is the CO2 concentration of the incompletely oxidized wastewater, mg / L;

[0140] k1 is the conversion coefficient, 0<k1<1;

[0141] k2 is the correction coefficient, 1.1<k2<1.5;

[0142] b is the loss coefficient, 0<b<0.3;

[0143] When Y>0.5, the redox potential of the incomplete oxidation treatment is reduced.

[0144] k1 is the conversion coefficient, and its value is related to the organic matter composition of the wastewater. It is generally determined through experiments. Taking ethanol as an example, k1=0.6; k2 is the correction coefficient, and its value is 1.1 to 1.5; b is the loss coefficient, and its value is 0 to 0.3, which is obtained based on the actual wastewater correction.

[0145] The specific usage of the above formula is as follows:

[0146] Firstly, a certain amount of industrial wastewater is treated using the non-complete oxidation coupled polymerization separation treatment method for wastewater provided by the present invention to obtain clean water.

[0147] During the treatment process, record the total COD in the industrial wastewater (recorded as A, obtained by multiplying the COD concentration in the industrial wastewater by the volume of the industrial wastewater), the total COD in the clean water (recorded as B, obtained by multiplying the COD concentration in the clean water by the volume of the clean water), and the total COD contained in the solid precipitate obtained by separation treatment (recorded as C, converted into COD using the mass of organic matter in the solid precipitate. If the total amount of COD converted into carbon dioxide escape due to mineralization during the treatment process is D, then D=(ABC). The mineralization rate Y=D / A can be further calculated.

[0148] At the same time, during the above treatment process, the COD concentration X1 of industrial wastewater, the COD concentration X2 of clean water, the CO2 concentration C1 of pre-catalytic wastewater, and the CO2 concentration C2 of incompletely oxidized wastewater were recorded to obtain a set of relationships between X1, X2, C1, C2 and the mineralization rate Y.

[0149] Repeat the experiment using the above method to obtain multiple sets of relationships between X1, X2, C1, C2 and mineralization rate Y, and then use mathematical methods to obtain the values ​​of k1, k2, and b. Then, by measuring only the values ​​of X1, X2, C1, and C2, the mineralization degree Y of industrial wastewater in the current treatment process can be obtained.

[0150] Furthermore, the treatment process of industrial wastewater can be guided by the mineralization degree Y of industrial wastewater. For example, the mineralization degree is used to describe the degree to which organic matter in industrial wastewater is completely oxidized to carbon dioxide. It is generally believed that when Y<0.5, the operating drug consumption is more economical. Therefore, Y>0.5 represents excessive oxidation of organic matter to carbon dioxide, which means that the treatment cost is high due to high drug consumption. At this time, less organic matter can be completely oxidized by reducing the redox potential of the incomplete oxidation treatment. The present invention does not limit the method of reducing the redox potential. In one embodiment, it can be achieved by adjusting the amount of oxidant added and controlling the reaction pH. Specifically, the redox potential of the incomplete oxidation treatment can be reduced by reducing the amount of oxidant added in the incomplete oxidation treatment or by increasing the pH of the treatment environment of the incomplete oxidation treatment.

[0151] In one embodiment, the treatment pressure of the pre-catalytic treatment is 0.05-0.1 MPa. The appropriate treatment pressure can complete the mixing reaction between the industrial wastewater and hydrogen peroxide through hydraulic action, and can also make the multi-metal doped FeOCl catalyst in the 1-pre-catalytic unit present a fluidized state and fully contact with the water flow, thereby better exerting the catalytic ability.

[0152] The second aspect of the present invention provides a wastewater non-complete oxidation coupled polymerization separation treatment system, such as Figure 1As shown, the system includes 1-pre-catalytic unit, 2-non-complete oxidation unit, 3-neutralization unit, and 4-loading clarification separation unit which are connected in sequence. That is, the outlet of 1-pre-catalytic unit is connected to the inlet of 2-non-complete oxidation unit, the outlet of 2-non-complete oxidation unit is connected to the inlet of 3-neutralization unit, and the outlet of 3-neutralization unit is connected to the inlet of 4-loading clarification separation unit. Among them, 1-pre-catalytic unit is used to perform pre-catalytic treatment, 2-non-complete oxidation unit is used to perform non-complete oxidation treatment, 3-neutralization unit is used to perform neutralization treatment, 4-loading clarification separation unit is used to perform loading clarification separation treatment, and the system is continuous flow operation. The present invention does not limit the specific equipment selection of the above-mentioned units, and reaction vessels that meet the various treatment requirements in the field can be used. The above three units cannot be replaced, there is an internal logic, and they cannot be reversed.

[0153] For example, Figure 2 As shown, in one embodiment, the 1-pre-catalytic unit can be a 101-pre-catalytic reactor, and the inlet and outlet of the 101-pre-catalytic reactor are the inlet and outlet of the 1-pre-catalytic unit; the 2-non-complete oxidation unit can be a 201-non-complete oxidation reactor, and the inlet and outlet of the 201-non-complete oxidation reactor are the inlet and outlet of the 2-non-complete oxidation unit; the 3-neutralization unit can be a 301-neutralization reactor, and the inlet and outlet of the 301-neutralization reactor are the inlet and outlet of the 3-neutralization unit.

[0154] The 4-loading clarification separation unit includes a 401-loading clarification reactor and a 402-inclined plate sedimentation tank which are interconnected, wherein the 401-loading clarification reactor and the 402-inclined plate sedimentation tank are co-constructed. The 401-loading clarification reactor is used to mix the neutralized wastewater with the coagulant and the polymer carrier, and the effluent enters the 402-inclined plate sedimentation tank for solid-liquid separation. The inlet of the 401-loading clarification reactor is the inlet of the 4-loading clarification separation unit.

[0155] In one embodiment, the 3-neutralization unit may further include an air stirring device to achieve uniform mixing of the materials.

[0156] It is understandable that the 4-loading clarification separation unit can also be split into a loading clarification unit and a separation unit, wherein the loading clarification unit is used to perform the mixing process of the neutralized wastewater with the flocculant and the polymer carrier, and the separation unit is used to perform solid-liquid separation treatment. The present invention also does not limit the specific equipment selection of the above units, and a reaction container that meets the various treatment requirements in the art can be used.

[0157] The 1-pre-catalytic unit is provided with a multi-metal doped FeOCl catalyst, which is packaged in a mesh box and installed as a fixed bed in the 1-pre-catalytic unit. When industrial wastewater passes through the 1-pre-catalytic unit, due to the impact of water flow and pressure, the catalyst particles are in a fluidized state in the fixed bed and fully contact with the wastewater to cause a catalytic reaction. The 2-non-complete oxidation unit also includes a multi-metal doped FeOCl catalyst with a particle size of less than 1 mm.

[0158] Furthermore, the 2-non-complete oxidation unit is also provided with a carbon dioxide sensor, which can detect the liquid phase carbon dioxide concentration of the treated material in the 2-non-complete oxidation unit. More specifically, the carbon dioxide sensor can be respectively arranged at the inlet and outlet of the 2-non-complete oxidation unit, and is used to detect the CO2 concentration of the pre-catalytic wastewater and the CO2 concentration of the non-complete oxidation wastewater, respectively.

[0159] In addition, in one embodiment, the 2-non-complete oxidation unit also includes a circulating water pump, and the circulating outlet of the 2-non-complete oxidation unit is connected to the circulating inlet of the 2-non-complete oxidation unit through the circulating water pump. Specifically, the 2-non-complete oxidation unit also includes a circulating water pump, and under the drive of the circulating water pump, the contents of the 2-non-complete oxidation unit enter the pipeline from the circulating outlet of the 2-non-complete oxidation unit, and then return to the 2-non-complete oxidation unit from the circulating inlet of the 2-non-complete oxidation unit to achieve a complete mixing reaction of the catalyst, reagent, and wastewater in the 2-non-complete oxidation unit. In one embodiment, the ratio of the circulating water volume to the water inlet can be controlled to be 2 to achieve a better treatment effect. Specifically, the 201-non-complete oxidation reactor may include a circulating water pump, and under the drive of the circulating water pump, the contents of the 201-non-complete oxidation reactor enter the pipeline from the circulating outlet of the 201-non-complete oxidation reactor, and then return to the 201-non-complete oxidation reactor from the circulating inlet of the 201-non-complete oxidation reactor to achieve a complete mixing reaction of the catalyst, reagent, and wastewater in the 201-non-complete oxidation reactor.

[0160] The incomplete oxidative coupled polymerization separation and treatment method for wastewater provided by the present invention is described below through specific implementation methods.

[0161] The multi-metal doped FeOCl catalyst was prepared as follows:

[0162] 1) Calcine activated carbon with a particle size of 3-5 mm at 450 °C in a muffle furnace for 3 h, then soak the activated carbon in a 0.5 mol / L hydrochloric acid solution and stir for 12 h; rinse with clean water continuously until the leaching solution becomes clear and the pH is neutral; after solid-liquid separation, place the filtered activated carbon in an oven and dry it at 80 °C for 8 h to obtain a carrier.

[0163] 2) Take FeCl3, CuCl2, MnCl2, and NiCl2 and dissolve them in deionized water to obtain an aqueous solution including iron ions and element X. In the solution, the concentrations of Fe, Cu, Mn, and Ni are 5mmol / L, 2.5mmol / L, 2.5mmol / L, and 0.8mmol / L, respectively. Mix the solution with the activated carbon carrier at a volume ratio of 10:1, put it into a vacuum defoaming barrel, evacuate it to 0.1MPa, and keep it standing under vacuum for 24 hours to enable the carrier to fully absorb the active components in the solution under vacuum pressure. Subsequently, the treatment system is subjected to solid-liquid separation, and the solid phase obtained is the first intermediate catalyst.

[0164] 3) The first intermediate catalyst was dried in an oven at 100° C. for 12 h. The dried first intermediate catalyst was placed in a muffle furnace, heated to 250° C. at a heating rate of 5° C. / min, calcined for 3 h in an air atmosphere, and then allowed to stand and cooled to obtain a second intermediate catalyst.

[0165] 4) Take 10 parts by weight of the second intermediate catalyst and 1 part by weight of MoS2 and disperse them in 1000 parts by weight of water, put the obtained mixed system into a vacuum defoaming barrel, evacuate to 0.1 MPa, and keep it standing under vacuum for 24 hours. Then, perform solid-liquid separation on the treated system, and the obtained solid phase material is the third intermediate catalyst.

[0166] 5) The third intermediate catalyst was dried in an oven at 100° C. for 12 h. The dried third intermediate catalyst was placed in a muffle furnace, heated to 200° C. at a heating rate of 5° C. / min, calcined for 3 h in an air atmosphere, and then allowed to stand and cooled to obtain a multi-metal doped FeOCl catalyst.

[0167] The above catalysts are placed in 101-pre-catalytic reactor and 201-incomplete oxidation reactor respectively for treating industrial wastewater.

[0168] Examples 1-3

[0169] Example 1-3 uses Figure 2 The non-complete oxidation coupled polymerization separation treatment system of the wastewater shown is executed. The industrial wastewater is taken from the effluent of the secondary sedimentation tank after the printing and dyeing and chemical comprehensive wastewater is treated by biological treatment-sedimentation separation. The main organic pollutants contained in it are benzene, aniline, toluene, phthalates, etc. The industrial wastewater with different COD concentrations is taken and the treatment process is repeated 3 times. The common treatment process is as follows:

[0170] 1) The pH of industrial wastewater is about 7, and the COD concentration is shown in Table 1. Sulfuric acid is added to the industrial wastewater to adjust the pH, and a small amount of hydrogen peroxide is added to the pre-catalytic reaction unit to control the pH to 5.5, so that it enters the 101-pre-catalytic reactor equipped with a multi-metal doped FeOCl catalyst for pre-catalytic treatment. The hydraulic retention time of the pre-catalytic treatment is 2 minutes, and pre-catalytic wastewater is obtained.

[0171] 2) The pre-catalytic wastewater enters the 201-non-complete oxidation reactor for non-complete oxidation treatment. Ferrous sulfate and hydrogen peroxide are added to the pre-catalytic wastewater to make the pH of the treatment environment of the non-complete oxidation treatment 4.5, the redox potential 200-400mV, the hydraulic retention time 30min, and obtain non-complete oxidation wastewater.

[0172] 3) The incompletely oxidized wastewater enters the 301-neutralization reactor, and NaOH is added to the incompletely oxidized wastewater to adjust its pH to 7 to obtain neutralized wastewater.

[0173] 4) The neutralized wastewater enters 401-loading clarification reactor. PAC and polymer carrier (ore containing metal ions) are added to the neutralized wastewater for loading clarification treatment. Among them, the PAC dosage is 5-10 mg / L (calculated in terms of effective aluminum content), and the polymer carrier dosage is 8% of the volume of the neutralized wastewater. Then, it is separated and treated in 402-inclined plate sedimentation tank to obtain clean water.

[0174] The specific execution conditions of the above process are shown in Table 1.

[0175] Industrial wastewater, incompletely oxidized wastewater obtained after pre-oxidation treatment and incompletely oxidized treatment (without polymerization separation treatment), and clean water obtained after loading clarification separation treatment were taken respectively, and the COD was measured respectively. The results are shown in Table 1.

[0176] It can be seen from Table 1 that after being treated by the non-complete oxidation coupled polymerization separation treatment method for wastewater provided by the present invention, the clean water quality obtained in each embodiment can meet the Class A discharge standard requirements.

[0177] Table 1

[0178]

[0179] In order to analyze the ratio of COD removal by incomplete oxidation and complete mineralization, the solid phase obtained after loading clarification and separation treatment was respectively taken and analyzed for the ratio of volatile solid content to total solid content (VSS / TSS). The main organic functional groups of the polymer precipitation solid phase obtained in Example 1 were analyzed by Fourier infrared spectroscopy. The results are shown in Tables 2 and Figure 3 .

[0180] Table 2

[0181]

[0182] Depend on Figure 3 It can be seen that the solid phase obtained by separation is enriched with the molecular carboxylation and aldehyde intermediates of organic pollutants in industrial wastewater, among which 3356 cm -1 The absorption peak at 1625 cm corresponds to the vibration of hydroxyl (-OH). -1 The absorption peak at 1499 cm corresponds to the stretching vibration of the carbon-carbon double bond. -1 The absorption peak at 1384 cm corresponds to the stretching vibration of sp2 CH of the benzene ring skeleton (-C=C-). -1 The absorption peak at 950cm corresponds to the in-plane bending vibration of the CH ring of the benzene ring. -1 The absorption peak at corresponds to the out-of-plane bending vibration of COH in carboxylic acid.

[0183] From Table 2, and Figure 3 It can be seen that the organic matter present in the solid phase is the intermediate products of molecular carboxylation, formaldehyde and other organic pollutants in industrial wastewater. This shows that the wastewater treatment method provided by the present invention can oxidize macromolecular organic matter into intermediate products such as molecular carboxylation and formaldehyde, enrich them with metal salt complexes, and remove them after complexation to form suspended flocs.

[0184] In addition, for Example 1: It can be seen from Table 1 that, compared with industrial wastewater, the COD removal rate in clean water (i.e., removal by complete mineralization and polymerization separation) is about 60%, and the COD removal rate in neutralized wastewater (i.e., removal by complete mineralization) is only about 10%, that is, the COD removed by complete mineralization accounts for about 16.7% of the total COD removed, and the COD removed by polymerization separation accounts for about 83.3% of the total COD removed.

[0185] For Example 2: It can be seen from Table 1 that, compared with industrial wastewater, the COD removal rate in clean water (i.e., removal by complete mineralization and polymerization separation) is about 65.6%, and the COD removal rate in neutralized wastewater (i.e., removal by complete mineralization) is only about 17.4%, that is, the COD removed by complete mineralization accounts for about 26.5% of the total COD removed, and the COD removed by polymerization separation accounts for about 73.5% of the total COD removed.

[0186] For Example 3: It can be seen from Table 1 that, compared with industrial wastewater, the COD removal rate in clean water (i.e., removal by complete mineralization and polymerization separation) is about 57.1%, and the COD removal rate in neutralized wastewater (i.e., removal by complete mineralization) is only about 21.3%, that is, the COD removed by complete mineralization accounts for about 37.3% of the total COD removed, and the COD removed by polymerization separation accounts for about 62.7% of the total COD removed.

[0187] The above content shows that, by analyzing the ratio of mineralization reaction and polymerization separation, it can be seen that the COD removed by polymerization separation accounts for 60-85% of the total removal, while the COD removed by complete mineralization accounts for 15-40% of the total removal.

[0188] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for treating wastewater by incomplete oxidation coupled polymerization separation, characterized in that: The method is performed using a wastewater non-complete oxidation coupled polymerization separation treatment system comprising a pre-catalytic unit, a non-complete oxidation unit, a neutralization unit, and a loading clarification separation unit which are connected in sequence; The pre-catalytic unit and the incomplete oxidation unit are provided with a multi-metal doped FeOCl catalyst; wherein the multi-metal doped FeOCl catalyst increases the surface active centers by simultaneously growing a low-valent metal catalyst and a high-valent metal catalyst on a carrier, improves the electron circulation rate inside and outside the catalyst crystal structure, accelerates the Fe(II) / Fe(III) circulation, and improves the catalytic efficiency of hydrogen peroxide; and the O on the surface of FeOCl connects the Fe and Cl sites to adsorb and activate pollutants and hydrogen peroxide, promoting the redox reaction; The method comprises: Allowing industrial wastewater with a pH of 5.0-5.5 to enter a pre-catalytic unit, adding hydrogen peroxide accounting for 30-50% of the total amount of hydrogen peroxide added to the industrial wastewater, performing pre-catalytic treatment on the industrial wastewater, and obtaining pre-catalytic wastewater; The pre-catalytic wastewater is allowed to enter the incomplete oxidation unit, ferrous salt and hydrogen peroxide accounting for 50-70% of the total amount of hydrogen peroxide added are added to the pre-catalytic wastewater, and the pre-catalytic wastewater is subjected to incomplete oxidation treatment to obtain incompletely oxidized wastewater; Allowing the incompletely oxidized wastewater to enter the neutralization unit, performing a neutralization treatment on the incompletely oxidized wastewater to make the incompletely oxidized wastewater neutral, and obtaining neutralized wastewater; Allowing the neutralized wastewater to enter the loading, clarifying and separating unit, adding a coagulant and a polymer carrier to the neutralized wastewater, and performing loading, clarifying and separating treatment on the neutralized wastewater to obtain clean water; The treatment environment pH of the pre-catalytic treatment is 5.0-5.5, and the hydraulic retention time is 2-5min; The treatment environment pH of the incomplete oxidation treatment is 4-5, the redox potential is 200-400mV, and the hydraulic retention time is 10-30min; The low-valent metal catalyst is FeOCl doped with an X element, wherein the X element is selected from at least one of Cu, Mn, and Ni; The high-valent metal catalyst is selected from at least one of MoS2 and WS2; The carrier is selected from at least one of zeolite, volcanic rock and activated carbon.

2. The method for treating wastewater by incomplete oxidation coupled polymerization separation according to claim 1, characterized in that: In the pre-catalytic treatment, the dosage of hydrogen peroxide is 30-50 mg / L.

3. The method for treating wastewater by incomplete oxidation coupled polymerization separation according to claim 2, characterized in that: In the incomplete oxidation treatment, the ferrous salt is ferrous sulfate, the dosage is 60-120 mg / L, and the dosage of hydrogen peroxide is 70-100 mg / L.

4. The method for treating wastewater by incomplete oxidation coupled polymerization separation according to claim 3, characterized in that: The multi-metal doped FeOCl catalyst is prepared using a method comprising the following process: contacting an aqueous solution including iron ions and element X with a carrier to obtain a first intermediate catalyst; performing a first calcination treatment on the first intermediate catalyst to obtain a second intermediate catalyst; contacting the second intermediate catalyst with the high-valent metal catalyst to obtain a third intermediate catalyst; The third intermediate catalyst is subjected to a second calcination treatment to obtain the multi-metal doped FeOCl catalyst.

5. The method for treating wastewater by incomplete oxidation coupled polymerization separation according to claim 4, characterized in that: The particle size of the polymer carrier is 0.3-0.8 mm and the density is 3-5 g / cm 3 The dosage is 5-10% of the volume of the neutralized wastewater.

6. The method for treating wastewater by incomplete oxidation coupled polymerization separation according to claim 5, characterized in that: The hydraulic retention time of the loading clarification separation treatment is 30-40 minutes.

7. The method for treating wastewater by incomplete oxidation coupled polymerization separation according to claim 1, characterized in that: Also includes: The mineralization degree of industrial wastewater was calculated using Equation 1; Y=k1k2(X1-X2) / (C1-C2)+b Formula 1; in, Y is the mineralization degree of industrial wastewater; 0<Y<1; X1 is the COD concentration of industrial wastewater, mg / L; X2 is the COD concentration of clean water, mg / L; C1 is the CO2 concentration of pre-catalytic wastewater, mg / L; C2 is the CO2 concentration of the incompletely oxidized wastewater, mg / L; k1 is the conversion coefficient, 0<k1<1; k2 is the correction coefficient, 1.1<k2<1.5; b is the loss coefficient, 0<b<0.3; When Y>0.5, the redox potential of the incomplete oxidation treatment is reduced.

8. The method for separation and treatment of wastewater by non-complete oxidation coupled polymerization according to any one of claims 1 to 7, characterized in that: The treatment pressure of the pre-catalytic treatment is 0.05-0.1Mpa.

9. A wastewater non-complete oxidation coupled polymerization separation treatment system for performing the wastewater non-complete oxidation coupled polymerization separation treatment method according to any one of claims 1 to 8, characterized in that: It includes a pre-catalytic unit, a non-complete oxidation unit, a neutralization unit, and a loading clarification separation unit which are connected in sequence; The pre-catalytic unit and the incomplete oxidation unit are provided with a multi-metal doped FeOCl catalyst.

10. The wastewater non-complete oxidation coupled polymerization separation treatment system according to claim 9, characterized in that: The incomplete oxidation unit is provided with a carbon dioxide sensor; and / or, The incomplete oxidation unit further includes a circulating water pump, and a circulating outlet of the incomplete oxidation unit is connected to a circulating inlet of the incomplete oxidation unit through the circulating water pump.

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