Multi-metal supported catalyst as well as preparation method and application thereof

Abstract

The invention provides a multi-metal supported catalyst as well as a preparation method and application thereof. The multi-metal supported catalyst comprises a low-valence metal catalyst, a high-valence metal catalyst and a carrier, the low-valence metal catalyst is FeOCl doped with an element X, and the element X is selected from at least one of Cu, Mn and Ni; the high-valence metal catalyst is selected from at least one of MoS2 and WS2; the carrier is selected from at least one of zeolite, pelelith and activated carbon. According to the multi-metal supported catalyst provided by the invention, the low-valence metal catalyst and the high-valence metal catalyst are simultaneously supported on the carrier, so that the surface active center of the catalyst is increased, meanwhile, the circulation rate of Fe (II) / Fe (II) is increased, and the multi-metal supported catalyst has relatively high catalytic efficiency.

Description

Technical Field

[0001] The invention belongs to the field of heterogeneous catalysis technology and industrial wastewater treatment, and in particular relates to a multi-metal supported catalyst and a preparation method and application thereof. Background Art

[0002] With the rapid development of industrialization in my country, a large number of pollutants discharged from industrial production activities enter the soil, water bodies and atmospheric environment, leading to increasingly serious environmental problems. Wastewater discharged from industrial activities usually contains a variety of organic pollutants. Due to the complex composition of wastewater, high concentration of pollutants and high toxicity, conventional pretreatment and biological treatment methods can usually only remove most of the easily degradable pollutants, resulting in a large amount of difficult-to-degrade, toxic and harmful substances in the effluent, and the effluent quality is difficult to meet the standards. Therefore, the development of fast and efficient methods for removing difficult-to-degrade organic pollutants has become an urgent technical need. As an emerging sewage treatment technology, advanced oxidation technology mainly uses chemical reactions such as addition, substitution, electron transfer, and bond breaking between strong oxidizing species and organic matter to decompose large molecular organic matter in water to generate low-toxic or non-toxic small molecular substances, or even complete mineralization.

[0003] Fenton / Fenton-like catalytic oxidation technology is one of the most widely used advanced oxidation technologies. Its main principle is to use ferrous ions Fe 2+ The strong oxidizing hydroxyl radicals •OH are produced by reacting with hydrogen peroxide H2O2 under acidic conditions to achieve rapid degradation of organic pollutants. In the homogeneous Fenton catalytic process, the ferrous ions Fe uniformly distributed in the solution 2+ Reacts with hydrogen peroxide H2O2 to generate •OH, but this technology has Fe 2+ There are many problems such as slow regeneration rate, low H2O2 utilization rate, strict pH range requirements, incomplete organic matter degradation, and large amount of iron sludge production. The heterogeneous Fenton catalytic process uses solid catalysts (such as transition metals) to react with hydrogen peroxide at the solid-liquid interface of the catalyst to generate •OH. This technology can theoretically expand the pH range of wastewater, reduce ferrous iron addition and iron sludge production, and has higher catalytic efficiency and catalyst reusability. However, the Fe(III) / Fe(II) cycle rate in most iron-based solid-phase catalysts is still slow, which seriously limits the continued progress of Fenton-like reactions. As a result, in practical applications, a large amount of H2O2 still needs to be added to drive and accelerate the redox cycle of iron, which in turn causes a large amount of H2O2 to be ineffectively decomposed and wasted in the reaction. Therefore, designing and developing stable and efficient Fenton-like catalysts and reducing the amount of H2O2 used are crucial to improving the catalytic activity of heterogeneous Fenton reactions.

[0004] Compared with conventional iron oxide catalytic materials (such as α-FeOOH, α-Fe2O3, etc.), iron oxychloride catalyst (FeOCl) has a unique two-dimensional layered stacking structure and a large number of unsaturated Fe(III) sites, showing strong H2O2 activation ability and high •OH generation rate, and has the technical potential to reduce the amount of H2O2 used. However, the existing FeOCl catalyst is often modified by single metal doping. The single metal doped in the catalyst has limited electron donation ability to Fe(III) in the structure and cannot quickly regenerate Fe(II), resulting in low catalytic efficiency. The amount of H2O2 required in the process of pollutant degradation is still large, and it is impossible to effectively save reagents in practical applications.

[0005] Therefore, developing an iron oxychloride catalyst with higher catalytic efficiency has become a research direction in this field. Summary of the invention

[0006] The invention provides a multi-metal supported catalyst, which has the technical effect of high catalytic efficiency.

[0007] The present invention also provides a method for preparing a multi-metal supported catalyst, which has the technical effects of simple process, high preparation efficiency and good industrial application prospect.

[0008] The invention also provides a method for removing organic matter in wastewater, which has the characteristic of high treatment efficiency.

[0009] The present invention provides a multi-metal supported catalyst, which includes a low-valent metal catalyst, a high-valent metal catalyst, and a carrier;

[0010] 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;

[0011] The high-valent metal catalyst is selected from at least one of MoS2 and WS2;

[0012] The carrier is selected from at least one of zeolite, volcanic rock and activated carbon.

[0013] The multi-metal supported catalyst as described above, wherein the low-valent metal catalyst is FeOCl doped with Cu, Mn and Ni elements;

[0014] In the low-valent metal catalyst, the molar ratio of Fe element, Cu element, Mn element and Ni element is (1-5): (0.2-1): (0.2-1): (0.08-0.4).

[0015] The multi-metal supported catalyst as described above, wherein the high-valent metal catalyst is MoS2.

[0016] In the multi-metal supported catalyst as described above, the ratio of the sum of the amounts of iron element and X element to the sum of the amounts of metal elements in the high-valent metal catalyst is 5-15.

[0017] The multi-metal supported catalyst as described above, wherein the catalyst is prepared by a method comprising the following process:

[0018] contacting an aqueous solution including iron ions and element X with a carrier to obtain a first intermediate catalyst;

[0019] performing a first calcination treatment on the first intermediate catalyst to obtain a second intermediate catalyst;

[0020] contacting the second intermediate catalyst with the high-valent metal catalyst to obtain a third intermediate catalyst;

[0021] The third intermediate catalyst is subjected to a second calcination treatment to obtain the multi-metal supported catalyst.

[0022] A method for preparing a multi-metal supported catalyst, by which any of the above multi-metal supported catalysts can be prepared. The method comprises the following steps:

[0023] contacting an aqueous solution including iron ions and element X with a carrier to obtain a first intermediate catalyst;

[0024] performing a first calcination treatment on the first intermediate catalyst to obtain a second intermediate catalyst;

[0025] contacting the second intermediate catalyst with the high-valent metal catalyst to obtain a third intermediate catalyst;

[0026] The third intermediate catalyst is subjected to a second calcination treatment to obtain the multi-metal supported catalyst.

[0027] The method for preparing a multi-metal supported catalyst as described above, wherein in the aqueous solution comprising iron ions and element X, the molar concentration ratio of Fe element, Cu element, Mn element and Ni element is (5-25): (1-5): (1-5): (0.4-2); and / or,

[0028] The volume ratio of the aqueous solution including iron ions and element X to the carrier is (5-10):1; and / or,

[0029] The mass ratio of the second intermediate catalyst to the high-valent metal catalyst is 1:(1-10).

[0030] The method for preparing the multi-metal supported catalyst as described above, wherein the first calcination treatment is carried out in an air atmosphere, the treatment time is 1-5 hours, the treatment temperature is 200-250° C., and the heating rate is 3-6° C. / min; and / or,

[0031] The second calcination treatment is carried out in an air atmosphere, the treatment time is 1-5 hours, the treatment temperature is 200-250° C., and the heating rate is 3-6° C. / min.

[0032] The method for preparing the multi-metal supported catalyst as described above, wherein an aqueous solution including iron ions and element X is brought into contact with a carrier to obtain a first intermediate catalyst, specifically comprises the following steps:

[0033] Mixing an aqueous solution including iron ions and element X with a carrier, and allowing the obtained mixed system to stand in an environment of less than or equal to 0.1 MPa for 12-72 hours to obtain a first intermediate catalyst; and / or,

[0034] The second intermediate catalyst is contacted with the high-valent metal catalyst to obtain the second intermediate catalyst, which specifically includes the following process:

[0035] The high-valent metal catalyst and the low-valent supported catalyst are dispersed in water, and the obtained mixed system is allowed to stand in an environment of less than or equal to 0.1 MPa for 12-72 hours to obtain a second intermediate catalyst.

[0036] The present invention also provides a method for removing organic matter in wastewater, which comprises contacting any one of the above multi-metal supported catalysts with hydrogen peroxide and the wastewater.

[0037] The multi-metal supported catalyst provided by the present invention has a high catalytic efficiency by simultaneously loading a low-valent metal catalyst and a high-valent metal catalyst on a carrier, thereby increasing the active centers on the catalyst surface and improving the Fe(II) / Fe(II) circulation rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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.

[0039] Figure 1 This is the XRD spectrum of the multi-metal supported catalyst prepared in Example 1. DETAILED DESCRIPTION

[0040] 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.

[0041] In the prior art, the traditional FeOCl catalyst has the technical defects of low catalytic performance, requiring a large amount of hydrogen peroxide to be added, and high operating costs. The inventors found through in-depth research that the reason for the above defects is that the two-dimensional layered structure of the traditional FeOCl catalyst has limited active sites and the circulation rate of Fe(III) / Fe(II) is slow, resulting in low catalytic performance in practical applications. Therefore, if the structure of the FeOCl catalyst can be changed to increase the number of active sites in the catalyst and the circulation rate of Fe(III) / Fe(II), the catalytic efficiency of the catalyst can be improved.

[0042] Based on this, the first aspect of the present invention protects a multi-metal supported catalyst, which includes a low-valent metal catalyst, a high-valent metal catalyst, and a carrier;

[0043] 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;

[0044] The high-valent metal catalyst is selected from at least one of MoS2 and WS2;

[0045] The carrier is selected from at least one of zeolite, volcanic rock and activated carbon.

[0046] The multi-metal supported catalyst provided by the present invention is a catalyst for removing organic pollutants in wastewater. Specifically, the catalyst provided by the present invention can be used together with hydrogen peroxide to construct a heterogeneous Fenton catalytic system to degrade organic pollutants.

[0047] The catalyst provided by the present invention includes 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.

[0048] 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.

[0049] 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.

[0050] The carrier is selected from at least one of zeolite, volcanic rock and activated carbon. The present invention does not limit the size of the carrier. In one embodiment, in order to better form a heterogeneous Fenton catalytic system, the particle size of the carrier can be controlled to be 3-5 mm.

[0051] In the multi-metal supported catalyst provided by the present invention, 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 supported 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.

[0052] 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, so that the low-valent metal catalyst is in situ grown on the surface of the carrier, and the carrier is in situ deposited on the surface of the low-valent metal catalyst by adsorbing the high-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 supported catalyst provided by the present invention.

[0053] The inventors have found that the multi-metal supported catalyst provided by the present invention has the characteristics of high catalytic performance. Specifically, when the multi-metal supported catalyst degrades organic pollutants in a heterogeneous Fenton catalytic system, under the premise of the same catalyst and hydrogen peroxide addition amount, it has a higher degradation rate for organic pollutants of the same concentration compared with the traditional FeOCl catalyst, and under the premise of having a higher degradation rate for organic pollutants of the same concentration, the multi-metal supported catalyst provided by the present invention only requires a lower amount of hydrogen peroxide addition compared with the traditional FeOCl catalyst. The inventors speculate that the reason may be that, first, in the high-valent metal catalyst, the doped low-valent transition metal atoms (X element) at least partially replace the Fe atoms in the FeOCl lattice. Since the atomic radius of the X element is different from that of the Fe atom, it affects the electron cloud distribution of the surrounding Fe atoms, thereby causing an increase in lattice defects and oxygen vacancies, forming more active sites and significantly accelerating the electron transfer process inside the catalyst; in addition, the multivalent state cycle of the X element, such as an electron transfer reaction in Cu(I) / Cu(II), can form a synergistic effect with the Fe(III) / Fe(II) cycle by accelerating the electron transfer process, thereby accelerating the Fe(III) / Fe(II) cycle. The increase in the number of active sites and the acceleration of the Fe(III) / Fe(II) cycle both make the multimetal supported catalyst provided by the present invention have a higher catalytic efficiency.

[0054] Furthermore, the synchronously loaded high-valent metal catalysts easily form sulfur vacancies, exposing more transition metal sites such as Mo(IV) and W(IV), promoting the circulation of high-valent metals such as Mo(IV) / Mo(VI) to produce two electron transfer reactions. The above electron transfer reaction process further accelerates the process of Fe(III) being reduced to form Fe(II), thereby further increasing the catalytic efficiency of the multi-metal loaded catalyst provided by the invention.

[0055] The multi-metal supported catalyst provided by the present invention is supported on a carrier by the simultaneous growth of a low-valent metal catalyst and a high-valent metal catalyst, thereby increasing the active centers on the catalyst surface and improving the dual-path electron circulation inside and outside the crystal structure of the FeOCl catalyst, greatly improving the circulation rate of Fe(II) / Fe(II), thereby obtaining a higher H2O2 catalytic efficiency.

[0056] In one embodiment, the low-valent metal catalyst is FeOCl doped with Cu, Mn and Ni. When FeOCl is doped with Cu, Mn and Ni at the same time, the multivalent cycle composed of Fe, Cu, Mn and Ni can further form a synergistic effect with the Fe(III) / Fe(II) cycle by accelerating the electron transfer process, further accelerating the reduction of Fe(III) to Fe(II), so that the multi-metal supported catalyst provided by the present invention has a higher catalytic efficiency. Further, in one embodiment, in the low-valent metal catalyst, the molar ratio of Fe, Cu, Mn and Ni is (5-25): (1-5): (1-5): (0.4-2). Due to the suitable element ratio, the above multi-metal supported catalyst has a higher catalytic efficiency.

[0057] In one embodiment, the high-valent metal catalyst is MoS2. Since MoS2 is more likely to form sulfur vacancies, exposing more Mo(IV) sites to cyclically generate two-electron transfer reactions, this multi-metal supported catalyst can further accelerate the process of Fe(III) being reduced to form Fe(II) and has a higher catalytic efficiency.

[0058] More specifically, in one embodiment, in the multi-metal supported catalyst provided by the present invention, the ratio of the sum of the amounts of the iron element and the X element to the sum of the amounts of the metal elements in the high-valent metal catalyst is 5-15. For example, when the low-valent metal catalyst is FeOCl doped with Cu, Mn, and Ni elements and the high-valent metal catalyst is MoS2, the above ratio is the ratio of the sum of the amounts of the Fe, Cu, Mn, and Ni elements to the number of moles of the Mo element. When the metal elements in the low-valent metal catalyst and the high-valent metal catalyst have a suitable molar ratio, the metal elements cooperate with each other to exert the greatest promotion effect, accelerate the process of Fe(III) being reduced to form Fe(II), and further increase the catalytic efficiency of the multi-metal supported catalyst provided by the present invention.

[0059] Furthermore, in one embodiment, in the multi-metal supported catalyst provided by the present invention, the mass fraction of the high-valent metal catalyst is 0.5-5%. A high-valent metal catalyst with a suitable mass fraction can be combined with a low-valent metal catalyst to make the catalyst have a higher catalytic efficiency.

[0060] In one embodiment, the multi-metal supported catalyst provided by the present invention is prepared using a method comprising the following process:

[0061] contacting an aqueous solution including iron ions and element X with a carrier to obtain a first intermediate catalyst;

[0062] performing a first calcination treatment on the first intermediate catalyst to obtain a second intermediate catalyst;

[0063] contacting the second intermediate with a high-valent metal catalyst to obtain a third intermediate catalyst;

[0064] The third intermediate catalyst is subjected to a second calcination treatment to obtain a multi-metal supported catalyst.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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 supported catalyst.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] The second aspect of the present invention provides a method for preparing a multi-metal supported catalyst, which can be used to prepare the multi-metal supported catalyst provided in the first aspect of the present invention. The method comprises the following steps:

[0073] contacting an aqueous solution including iron ions and element X with a carrier to obtain a first intermediate catalyst;

[0074] performing a first calcination treatment on the first intermediate catalyst to obtain a second intermediate catalyst;

[0075] contacting the second intermediate catalyst with a high-valent metal catalyst to obtain a third intermediate catalyst;

[0076] The third intermediate catalyst is subjected to a second calcination treatment to obtain a multi-metal supported catalyst. The aqueous solution of iron ions and element X, the first intermediate catalyst, the first calcination treatment, the second intermediate catalyst, the third intermediate catalyst, and the second calcination treatment have the same meanings as above and are not described in detail herein.

[0077] The preparation method of the multi-metal supported catalyst provided by the present invention can prepare the FeOCl catalyst through a few steps of vacuum impregnation and calcination, which reduces the preparation cost and time, improves the preparation efficiency, and has good industrial application prospects.

[0078] In one embodiment, in the aqueous solution including iron ions and element X, the molar concentration ratio of Fe element, Cu element, Mn element, and Ni element is (5-25): (1-5): (1-5): (0.4-2). The appropriate concentration ratio of each metal element in the aqueous solution can make the prepared multi-metal supported catalyst have a suitable metal element molar ratio, thereby having a higher catalytic efficiency. Further, in the above aqueous solution, the molar concentrations of Fe element, Cu element, Mn element, and Ni element can be 1-5mmol / L, 0.2-1mmol / L, 0.2-1mmol / L, and 0.08-0.4mmol / L, respectively. The appropriate concentration of each metal element in the aqueous solution is conducive to faster loading of the metal elements on the carrier surface, thereby improving the preparation efficiency of the preparation method of the multi-metal supported catalyst provided by the present invention.

[0079] Furthermore, in the process of contacting the aqueous solution including iron ions and the X element with the carrier to obtain the first intermediate catalyst, the volume ratio of the aqueous solution including Fe ions and the X element to the carrier can be controlled to be (5-10): 1. Controlling the aqueous solution to the carrier to have a suitable volume ratio can ensure that the aqueous solution completely submerges the carrier during the contact between the two, so that the metal elements are loaded on the surface of the carrier more quickly, and further improve the preparation efficiency of the preparation method of the multi-metal supported catalyst provided by the present invention.

[0080] Furthermore, in the process of contacting the second intermediate catalyst with the high-valent metal catalyst to obtain the third intermediate catalyst, the mass ratio of the second intermediate catalyst to the high-valent metal catalyst can be controlled to be 1: (1-10). Controlling the second intermediate catalyst and the high-valent metal catalyst to have a suitable mass ratio can allow the high-valent metal catalyst to be loaded on the surface of the second intermediate catalyst more quickly, further improving the preparation efficiency of the preparation method of the multi-metal supported catalyst provided by the present invention.

[0081] In one embodiment, the first calcination treatment can be controlled to be carried out in an air atmosphere, with a treatment time of 1-5h, a treatment temperature of 200-250°C, and a heating rate of 3-6°C / min. Appropriate treatment conditions can make the low-valent metal catalyst more closely combined with the carrier; further, the second calcination treatment can be controlled to be carried out in an air atmosphere, with a treatment time of 1-5h, a treatment temperature of 200-250°C, and a heating rate of 3-6°C / min. Appropriate treatment conditions can make the high-valent metal catalyst on the surface of the third intermediate catalyst more closely combined with the carrier, so that the obtained catalyst has a higher catalytic efficiency.

[0082] More specifically, in one embodiment, an aqueous solution including iron ions and X elements is contacted with a carrier to obtain a first intermediate catalyst, specifically including mixing an aqueous solution including iron ions and X elements with a carrier, and the obtained mixed system is allowed to stand for 12-72h in an environment of less than or equal to 0.1MPa to obtain a first intermediate catalyst. In an environment with lower pressure, iron ions and X elements can be more absorbed by the carrier, and more low-valent metal catalysts are formed on the surface of the carrier, which has a higher catalytic efficiency; further, the second intermediate catalyst is contacted with a high-valent metal catalyst to obtain a second intermediate catalyst, specifically including dispersing a high-valent metal catalyst and a low-valent loaded catalyst in water, and the obtained mixed system is allowed to stand for 12-72h in an environment of less than or equal to 0.1MPa to obtain a second intermediate catalyst. Similarly, in an environment with lower pressure, the high-valent metal catalyst can be more absorbed by the second intermediate catalyst, so that the activity of the catalyst obtained is further improved.

[0083] The second aspect of the present invention provides a method for removing organic matter from wastewater, the method comprising contacting any one of the multi-metal supported catalysts provided in the first aspect of the present invention with hydrogen peroxide and wastewater to degrade the organic matter in the wastewater. Since the multi-metal supported catalyst provided by the present invention has the characteristic of high catalytic efficiency, the use of the catalyst to treat organic matter in wastewater has the characteristic of high treatment efficiency.

[0084] The present invention does not limit the specific method of using the above catalyst to treat organic matter, and common methods in the art can be used. In one embodiment, it includes using a beaker as a reaction container at room temperature, adding wastewater containing organic pollutants, the prepared catalyst and a certain amount of H2O2 into the container, controlling the pH between 3-5, and continuously stirring the solution until the reaction time is complete.

[0085] The present invention is further described below in conjunction with specific implementation methods.

[0086] Embodiment 1:

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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 supported catalyst.

[0092] Figure 1 is the XRD spectrum of the multi-metal supported catalyst prepared in Example 1, Figure 1 This shows that FeOCl and MoS2 materials have been successfully loaded on activated carbon, while Cu, Mn and Ni are difficult to load on activated carbon due to their low content. Figure 1 It is reflected in.

[0093] Embodiment 2:

[0094] This embodiment is basically the same as embodiment 1, except that in step 3), FeCl3, CuCl2, and MnCl2 are dissolved in deionized water to obtain an aqueous solution including iron ions and element X. In the solution, the concentrations of Fe, Cu, and Mn are 5.8 mmol / L, 2.5 mmol / L, and 2.5 mmol / L, respectively.

[0095] Embodiment 3:

[0096] This embodiment is basically the same as embodiment 1, except that in step 3), FeCl3 and CuCl2 are dissolved in deionized water to obtain an aqueous solution including iron ions and element X. In the solution, the molar ratios of the Fe element and the Cu element are 8.3 mmol / L and 2.5 mmol / L, respectively.

[0097] Embodiment 4:

[0098] This embodiment is basically the same as Embodiment 1, except that in step 4), MoS2 is replaced by WS2, and the molar amount of the W element in WS2 is equal to the molar amount of the Mo element in MoS2 used in Embodiment 1.

[0099] Embodiment 5:

[0100] This embodiment is basically the same as embodiment 1, except that in step 1), the activated carbon is replaced with zeolite particles with a particle size of 3-5 mm.

[0101] Embodiment 6:

[0102] This embodiment is basically the same as embodiment 1, except that in step 1), the activated carbon is replaced with volcanic rock particles with a particle size of 3-5 mm.

[0103] Embodiment 7:

[0104] This embodiment is basically the same as embodiment 1, except that, in step 3), FeCl3, CuCl2, MnCl2, and NiCl2 are dissolved in deionized water to obtain an aqueous solution including iron ions and element X. In the solution, the concentrations of Fe element, Cu element, Mn element, and Ni element are 5 mmol / L, 0.8 mmol / L, 0.8 mmol / L, and 2.5 mmol / L, respectively.

[0105] Embodiment 8:

[0106] This embodiment is basically the same as Embodiment 1, except that the added amount of MoS2 is 0.2 parts by weight.

[0107] Comparative Example 1:

[0108] This comparative example is basically the same as Example 1, except that step 4) and step 5) are not performed, and the second intermediate catalyst prepared in step 3) is used as the catalyst sample.

[0109] Comparative Example 2:

[0110] This comparative example is basically the same as Example 1, except that in step 2), FeCl3 is dissolved in deionized water to obtain an aqueous solution including iron ions. The concentration of Fe element in the solution is 10.8 mmol / L.

[0111] Test example:

[0112] 1. The catalyst samples obtained in each embodiment and comparative example were subjected to acidification and dissolution treatment, specifically, 10 g of the catalyst was added to 100 mL of a dissolving solution for dissolution, wherein the dissolving solution was obtained by mixing 50 mL of 68 wt% concentrated nitric acid and 50 mL of 30 wt% hydrogen peroxide. After dissolution, a treatment solution was obtained, and an ICP test was performed on the treatment solution to obtain the molar concentration (mmol / L) of each metal element in the treatment solution. The test results are shown in Table 1.

[0113] Table 1:

[0114]

[0115] The data in Table 1 were processed. Specifically, the iron content of each sample in Table 1 was assigned a value of 1, and the contents of other elements were adjusted according to their proportional relationship with the iron element. At the same time, the ratio of the sum of the contents of Fe, Cu, Mn, and Ni elements (denoted as A) to the sum of the contents of Mo and W elements (denoted as B) was calculated and filled in Table 2.

[0116] Table 2:

[0117]

[0118] 2. The catalyst sample prepared in Example 1 was used to perform the following tests:

[0119] Prepare 450 ml of phenol aqueous solution containing 100 mg / LCOD, adjust the pH of the phenol aqueous solution to 5 using 1M NaOH and 1M H2SO4, add 50 g of catalyst sample, and then add 30% concentration of hydrogen peroxide to make the hydrogen peroxide concentration in the reaction system reach the corresponding hydrogen peroxide dosage in Table 2. Control the pH of the reaction system to 3-5, and record the COD concentration in the solution after reacting for 30 minutes under continuous stirring. The experimental results are shown in Table 3.

[0120] Among them, COD concentration was measured using a Hach brand UV detector through the potassium dichromate method.

[0121] Table 3:

[0122]

[0123] 3. The catalyst samples prepared in the embodiments and comparative examples were used to perform the following tests:

[0124] Prepare 450 ml of phenol solution containing 100 mg / LCOD, adjust the pH of the solution to 5 using 1M NaOH and 1M H2SO4, add 50 g of catalyst sample, and then add 30% hydrogen peroxide to make the hydrogen peroxide concentration in the reaction system reach 0.5 g / L. Control the pH of the reaction system to 3-5, and record the COD concentration in the solution after reacting for 30 minutes under continuous stirring. The experimental results are shown in Table 4.

[0125] Table 4:

[0126]

[0127] As shown in Table 4, compared with the catalysts prepared in Comparative Examples 1 and 2, the catalysts prepared in Examples 1-8 have higher COD removal rates in the same period of time, indicating that the catalysts prepared in Examples 1-8 have higher catalytic efficiency. The reason may be that the catalyst prepared in Comparative Example 1 does not include a high-valent metal catalyst, and the catalyst prepared in Comparative Example 2 does not contain the X element.

[0128] Compared with Example 1, the catalytic efficiency of the catalysts prepared in Examples 2 and 3 is lower. The reason may be that in the catalysts prepared in Examples 2 and 3, the low-valent metal catalysts do not include Cu, Mn and Ni elements at the same time, and the synergistic effect with the Fe(III) / Fe(II) cycle is weak, resulting in a slower Fe(III) / Fe(II) cycle rate.

[0129] Compared with Example 1, the catalytic efficiency of the catalyst prepared in Example 4 is lower. The reason may be that WS2 is less likely to form sulfur vacancies than MoS2, so the Fe(III) / Fe(II) circulation rate in the prepared catalyst is slower.

[0130] Compared with Example 1, the catalytic efficiency of the catalysts prepared in Examples 5 and 6 is lower. The reason may be that zeolite and volcanic rock have smaller specific surface areas than activated carbon and have fewer exposed active sites, so the catalytic efficiency of the prepared catalysts is lower.

[0131] Compared with Example 1, the catalytic efficiency of the catalyst prepared in Example 7 is lower. The reason may be that the molar ratio of Fe, Cu, Mn and Ni in the low-valent metal catalyst is not suitable, resulting in a slow Fe(III) / Fe(II) circulation rate.

[0132] Compared with Example 1, the catalytic efficiency of the catalyst prepared in Example 8 is lower. The reason may be that the addition amount of the low-valent metal catalyst, MoS2, is too low, resulting in the ratio of the sum of the amounts of iron element and X element to the sum of the amounts of metal elements in the high-valent metal catalyst being not in a suitable range, thereby resulting in a lower catalytic efficiency of the prepared catalyst.

[0133] 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 multi-metal supported catalyst, characterized in that: Including low-valent metal catalysts, high-valent metal catalysts, and carriers; 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 multi-metal supported catalyst according to claim 1, characterized in that: The low-valent metal catalyst is FeOCl doped with Cu, Mn and Ni elements; In the low-valent metal catalyst, the molar ratio of Fe element, Cu element, Mn element and Ni element is (1-5): (0.2-1): (0.2-1): (0.08-0.4).

3. The multi-metal supported catalyst according to claim 1, characterized in that: The high-valent metal catalyst is MoS2.

4. The multi-metal supported catalyst according to claim 1, characterized in that: The ratio of the sum of the amounts of the iron element and the X element to the sum of the amounts of the metal elements in the high-valent metal catalyst is 5-15.

5. The multi-metal supported catalyst according to any one of claims 1 to 4, characterized in that: Prepared using a method comprising the following steps: 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 supported catalyst.

6. A method for preparing the multi-metal supported catalyst according to any one of claims 1 to 5, characterized in that: The steps include: 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 supported catalyst.

7. The method for preparing a multi-metal supported catalyst according to claim 6, characterized in that: In the aqueous solution comprising iron ions and element X, the molar concentration ratio of Fe element, Cu element, Mn element and Ni element is (5-25): (1-5): (1-5): (0.4-2); and / or, The volume ratio of the aqueous solution including iron ions and element X to the carrier is (5-10):1; and / or, The mass ratio of the second intermediate catalyst to the high-valent metal catalyst is 1:(1-10).

8. The method for preparing a multi-metal supported catalyst according to claim 6, characterized in that: The first calcination treatment is carried out in an air atmosphere, the treatment time is 1-5 hours, the treatment temperature is 200-250° C., and the heating rate is 3-6° C. / min; and / or, The second calcination treatment is carried out in an air atmosphere, the treatment time is 1-5 hours, the treatment temperature is 200-250° C., and the heating rate is 3-6° C. / min.

9. The method for preparing a multi-metal supported catalyst according to claim 6, characterized in that: The aqueous solution including iron ions and element X is contacted with a carrier to obtain a first intermediate catalyst, which specifically includes the following process: Mixing an aqueous solution including iron ions and element X with a carrier, and allowing the obtained mixed system to stand in an environment of less than or equal to 0.1 MPa for 12-72 hours to obtain a first intermediate catalyst; and / or, The second intermediate catalyst is contacted with the high-valent metal catalyst to obtain the second intermediate catalyst, which specifically includes the following process: The high-valent metal catalyst and the low-valent supported catalyst are dispersed in water, and the obtained mixed system is allowed to stand in an environment of less than or equal to 0.1 MPa for 12-72 hours to obtain a second intermediate catalyst.

10. A method for removing organic matter from wastewater, characterized in that: The multi-metal supported catalyst according to any one of claims 1 to 5 is contacted with hydrogen peroxide and the wastewater.

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