A ferrous sulfide catalyst and its preparation method and application

Abstract

This application specifically discloses a ferrous sulfide oxide catalyst, its preparation method, and application. The preparation method comprises the following steps: mixing a ferrous inorganic salt solution, a sulfur-containing inorganic salt solution, and an oxygen-containing compound solution to obtain a premixed solution, aging the solution, and obtaining a solid product, which is the ferrous sulfide oxide catalyst; wherein the molar concentration ratio of divalent sulfur to oxygen in the premixed solution is (0.5-1):(0.01-0.5). The ferrous sulfide oxide catalyst prepared in this application is capable of efficiently removing organic pollutants from phenol-containing wastewater.

Description

Technical Field

[0001] The present application relates to the field of water treatment technology, and in particular to a sulfide iron oxide catalyst and a preparation method and application thereof. Background Art

[0002] With the acceleration of industrialization, a large number of difficult-to-degrade organic pollutants are being discharged into water. Traditional water treatment technologies struggle to effectively remove these pollutants, such as phenol. If discharged without treatment, they can cause serious pollution to surface and groundwater, threatening drinking water safety. Furthermore, once organic pollutants like phenol enter water bodies, they can disrupt the balance of aquatic ecosystems and affect the survival of aquatic life.

[0003] The presence of high concentrations of organic pollutants makes wastewater treatment more difficult and increases treatment costs. Removing some organic pollutants through pretreatment can improve the biodegradability of wastewater and reduce the difficulty and cost of subsequent treatment. To date, many methods have been developed to treat organic pollutants in industrial wastewater, of which advanced oxidation technology (AOP) is the most widely used. However, existing research shows that the removal of organic micropollutants from water through advanced oxidation processes (AOPs) is hindered by excessive energy and / or chemical inputs and large amounts of residues caused by incomplete mineralization, which to some extent hinder the complete removal of organic pollutants in wastewater. Summary of the Invention

[0004] In order to efficiently remove organic pollutants in phenol wastewater, the present application provides a sulfide iron oxide catalyst and its preparation method and application.

[0005] In a first aspect, the present application provides a method for preparing a sulfide iron oxide catalyst, which adopts the following technical solution:

[0006] A method for preparing a sulfide iron oxide catalyst comprises the following steps:

[0007] Mixing a ferrous inorganic salt solution, a sulfur-containing inorganic salt solution and an oxygen-containing compound solution to obtain a premixed solution, aging the solution, and obtaining a solid phase product, which is the sulfide-iron oxide catalyst;

[0008] Wherein, the molar concentration ratio of divalent sulfur and oxygen in the premixed solution is (0.5-1): (0.01-0.5).

[0009] Preferably, after aging, the premix solution is centrifuged at 3000-7000 rpm for 2-5 minutes to perform solid-liquid separation.

[0010] The iron sulfide oxide catalyst prepared in the present application includes ferrous sulfide and iron sulfide oxide compounds. First, the presence of the iron sulfide oxide compound can reduce the excessive reaction activity of ferrous sulfide in the iron sulfide oxide catalyst to a certain extent. By controlling the molar concentrations of divalent sulfur and oxygen (oxygen introduced by oxygen-containing compounds and ferrous inorganic salts) in the premixed solution, the present application can adjust the activity of the iron sulfide oxide catalyst to an appropriate range, thereby avoiding the situation in which the ferrous sulfide has a poor effect on removing organic pollutants due to a violent reaction with an oxidant in the application of wastewater treatment. Secondly, the iron sulfide oxide catalyst prepared in the present application can activate organic pollutants by reducing the reduction potential of the pollutants, thereby inducing the non-decomposition oxidative transfer of organic pollutants from the bulk solution to the surface of the iron sulfide oxide catalyst; specifically, the divalent sulfur in the iron sulfide oxide catalyst can activate the adsorbed oxidant, and the divalent iron in the iron sulfide oxide catalyst can activate the adsorbed organic pollutants, so that the organic pollutants and the oxidant can undergo a 2-electron direct oxidation transfer process (DOTP) on the surface of the iron sulfide oxide catalyst. The generated organic pollutant intermediates are stabilized by the surface of the iron sulfide oxide catalyst and spontaneously undergo surface polymerization reaction or surface coupling reaction. The formed products are enriched on the surface of the iron sulfide oxide catalyst and converted into solid-phase precipitates, thereby separating and removing the organic pollutants in the wastewater from the water in the form of solid-phase sludge.

[0011] During the above reaction process, the iron sulfide oxide catalyst exhibits three major functions: activation, stabilization, and enrichment. This allows the iron sulfide oxide catalyst to exhibit advantages such as low consumption, large pollutant enrichment capacity, and no toxic byproducts in the application of purifying organic wastewater, and robust performance in real environmental matrices. This provides feasibility for DOTP as a new water pollution control technology for actual wastewater treatment. In addition, DOTP does not require external energy input, has low oxidant consumption, and does not produce residual byproducts. At the same time, the process for preparing the iron sulfide oxide catalyst in this application is simple and efficient, easy to achieve large-scale production, and does not require the use of expensive equipment during the production process, reducing the difficulty of preparation and production costs, and facilitating industrial application.

[0012] Preferably, the molar concentration ratio of divalent sulfur to iron in the premixed solution is (3-5): (0.05-3).

[0013] By further controlling the molar concentration ratio of divalent sulfur to iron in the mixed solution, the generated iron sulfide oxide catalyst can better activate and adsorb oxidants and organic pollutants in the application of treating phenol wastewater. On the one hand, the iron sulfide oxide catalyst can achieve efficient treatment of phenol wastewater with a small input amount. On the other hand, it can also reduce the dosage of the oxidant, thereby achieving rapid and efficient purification of phenol wastewater while reducing costs.

[0014] Preferably, during the aging process, the premix solution is allowed to stand at 20-25° C. for 1.5-3 h.

[0015] Preferably, the ferrous inorganic salt in the ferrous inorganic salt solution includes at least one of ferrous sulfate heptahydrate and ferrous chloride, and the concentration of ferrous ions in the premix solution is 0.1-2 mmol / L; the sulfur inorganic salt in the sulfur-containing inorganic salt solution includes sodium sulfide nonahydrate, and the concentration of sulfur ions in the premix solution is 0.1-2 mmol / L.

[0016] Preferably, the oxygen-containing compound solution includes an oxygen-containing inorganic salt, and the oxygen-containing inorganic salt includes at least one of calcium peroxide and alkaline hydrogen peroxide, and the concentration of peroxide ions in the premix solution is 0.1-2 mmol / L.

[0017] Preferably, the premix solution is subjected to a freeze-drying step after aging to obtain the iron sulfide oxide catalyst;

[0018] The temperature during the freeze-drying process is -60°C to -40°C, and the time is 15-24 hours.

[0019] In a second aspect, the present application provides a sulfide iron oxide catalyst, which adopts the following technical solution:

[0020] A sulfide iron oxide catalyst is prepared by the method described above.

[0021] In a third aspect, the present application provides an application of an iron sulfide oxide catalyst.

[0022] The invention discloses an application of a sulfide iron oxide catalyst for treating phenol-containing wastewater.

[0023] Preferably, treating the phenol-containing wastewater comprises the following steps: mixing the iron sulfide oxide catalyst with the phenol-containing wastewater and adjusting the pH value to obtain a mixed solution, and adding an oxidant to the mixed solution to obtain treated phenol wastewater;

[0024] Wherein, the pH value of the mixed solution is 3.2-4.0;

[0025] The COD concentration in the phenol wastewater is 5000-9000 mg / L, and the phenol concentration is 1.05-1.89 g / L.

[0026] By adjusting the pH value of the mixed solution, the surface properties of the iron sulfide oxide catalyst, the effective utilization of H2O2, and the adsorption and reactivity of phenol are synergistically optimized, thereby improving the degradation efficiency of the heterogeneous catalytic system while ensuring the stability of the iron sulfide oxide catalyst and the integrity of the reaction pathway. Therefore, at this pH value, the iron sulfide oxide catalyst in this application has good catalytic performance and can efficiently activate oxidants such as hydrogen peroxide to generate highly oxidizing hydroxyl radicals, thereby quickly and efficiently degrading organic pollutants in high-concentration phenol wastewater.

[0027] Preferably, the concentration of the oxidant in the mixed solution is 39-98 mmol / L; the dosage of the iron sulfide oxide catalyst in the mixed solution is 0.2-2 g / L.

[0028] The sulfide iron oxide catalyst of the present application only requires the addition of a very small amount of oxidant when removing high-concentration organic pollutants in phenol wastewater, thereby achieving efficient purification of wastewater while reducing application costs. DETAILED DESCRIPTION

[0029] For better understanding and implementation, the technical solution of the present application will be clearly and completely described below in conjunction with embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0031] Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as modified by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth herein are approximations that can vary depending upon the desired properties sought to be obtained.

[0032] As used herein, "and / or" means one or all of the mentioned elements.

[0033] As used herein, “including” and “comprising” encompasses the case where only the stated elements are present and also the case where there are other elements other than the stated elements.

[0034] All percentages in this application are by weight unless otherwise stated.

[0035] Unless otherwise indicated, as used in this specification, "a," "an," "an," and "the" are intended to include "at least one" or "one or more." For example, "a component" refers to one or more components, and thus more than one component is contemplated and may be employed or used in the practice of the described embodiment.

[0036] Example 1

[0037] 1. Preparation of Iron Sulfide Oxide Catalyst

[0038] S1, dissolving 0.2224 g of ferrous sulfate heptahydrate in 40 mL of deionized water to obtain a ferrous inorganic salt solution, dissolving 0.3666 g of sodium sulfide nonahydrate in 40 mL of deionized water to obtain a sulfur-containing inorganic salt solution, and dissolving 0.0468 g of calcium peroxide in 40 mL of deionized water to obtain an oxygen-containing compound solution; pouring the ferrous inorganic salt solution and the sulfur-containing inorganic salt solution into the oxygen-containing compound solution, stirring evenly, and allowing the solution to stand at room temperature for 2 h to obtain a premixed solution;

[0039] S2. The premixed solution was centrifuged at 5000 rpm for 3 minutes, and the supernatant was filtered to achieve solid-liquid separation. The obtained solid phase product was washed three times with deionized water, and ultrasonic dispersion was performed during each washing. The solid phase product was then centrifuged at 5000 rpm for 3 minutes. The obtained centrifuged product was frozen at -50°C for 20 hours, and finally placed in a freeze dryer and dried under vacuum and low temperature conditions to obtain a sulfide iron oxide catalyst.

[0040] 2. Application of iron sulfide oxide catalyst in the treatment of phenol-containing wastewater

[0041] The above-mentioned iron sulfide oxide catalyst (added amount 1 g / L) was mixed with 40 mL of a phenol wastewater solution (the phenol concentration in the phenol wastewater solution was 1.68 g / L and the COD concentration was 8000 mg / L). The pH value of the solution was adjusted to 4 using concentrated sulfuric acid to obtain a mixed solution. 98 mmol / L of hydrogen peroxide was added to the mixed solution. After mixing evenly, the phenol removal rate in the phenol wastewater could reach 85% within 3 hours, and the COD removal rate reached 85%.

[0042] Example 2

[0043] 1. Preparation of Iron Sulfide Oxide Catalyst

[0044] S1, dissolving 0.2224 g of ferrous sulfate heptahydrate in 40 mL of deionized water to obtain a ferrous inorganic salt solution, dissolving 0.3666 g of sodium sulfide nonahydrate in 40 mL of deionized water to obtain a sulfur-containing inorganic salt solution, and dissolving 0.0468 g of calcium peroxide in 40 mL of deionized water to obtain an oxygen-containing compound solution; pouring the ferrous inorganic salt solution and the sulfur-containing inorganic salt solution into the oxygen-containing compound solution, stirring evenly, and letting it stand for 2 hours to obtain a premixed solution;

[0045] S2. The premixed solution was centrifuged at 5000 rpm for 3 minutes, and the supernatant was filtered to achieve solid-liquid separation. The obtained solid phase product was washed three times with deionized water, and ultrasonic dispersion was performed during each washing. The solid phase product was then centrifuged at 5000 rpm for 3 minutes. The obtained centrifuged product was frozen at -50°C for 20 hours, and finally placed in a freeze dryer and dried under vacuum and low temperature conditions to obtain a sulfide iron oxide catalyst.

[0046] 2. Application of iron sulfide oxide catalyst in the treatment of phenol-containing wastewater

[0047] The above-mentioned iron sulfide oxide catalyst (added amount 1g / L) was mixed with 40mL of industrial wastewater solution (the phenol concentration in the industrial wastewater solution was 1.47g / L and the COD concentration was 7000mg / L), and the pH value of the solution was adjusted to 4 with concentrated sulfuric acid to obtain a mixed solution. 98mmol / L of hydrogen peroxide was added to the mixed solution and mixed evenly. The phenol removal rate in the phenol wastewater could reach 80% within 3 hours, and the COD removal rate reached 80%.

[0048] Example 3

[0049] 1. Preparation of Iron Sulfide Oxide Catalyst

[0050] S1, dissolving 0.2224 g of ferrous sulfate heptahydrate in 40 mL of deionized water to obtain a ferrous inorganic salt solution, dissolving 0.3666 g of sodium sulfide nonahydrate in 40 mL of deionized water to obtain a sulfur-containing inorganic salt solution, and dissolving 0.0468 g of calcium peroxide in 40 mL of deionized water to obtain an oxygen-containing compound solution; pouring the ferrous inorganic salt solution and the sulfur-containing inorganic salt solution into the oxygen-containing compound solution, stirring evenly, and letting it stand for 2 hours to obtain a premixed solution;

[0051] S2. The premixed solution was centrifuged at 5000 rpm for 3 minutes, and the supernatant was filtered to achieve solid-liquid separation. The obtained solid phase product was washed three times with deionized water, and ultrasonic dispersion was performed during each washing. The solid phase product was then centrifuged at 5000 rpm for 3 minutes. The obtained centrifuged product was frozen at -50°C for 20 hours, and finally placed in a freeze dryer and dried under vacuum and low temperature conditions to obtain a sulfide iron oxide catalyst.

[0052] 2. Application of iron sulfide oxide catalyst in the treatment of phenol-containing wastewater

[0053] The above-mentioned iron sulfide oxide catalyst (added amount 1g / L) was mixed with 40mL of industrial wastewater solution (the phenol concentration in the industrial wastewater solution was 1.26g / L and the COD concentration was 6000mg / L), and the pH value of the solution was adjusted to 4 with concentrated sulfuric acid to obtain a mixed solution. 98mmol / L of hydrogen peroxide was added to the mixed solution and mixed evenly. Within 3 hours, the phenol removal rate in the phenol wastewater could reach 70%, and the COD removal rate reached 70%.

[0054] Example 4

[0055] 1. Preparation of Iron Sulfide Oxide Catalyst

[0056] S1, dissolving 0.3336 g of ferrous sulfate heptahydrate in 40 mL of deionized water to obtain a ferrous inorganic salt solution, dissolving 0.3666 g of sodium sulfide nonahydrate in 40 mL of deionized water to obtain a sulfur-containing inorganic salt solution, and dissolving 0.0702 g of calcium peroxide in 40 mL of deionized water to obtain an oxygen-containing compound solution; pouring the ferrous inorganic salt solution and the sulfur-containing inorganic salt solution into the oxygen-containing compound solution, stirring evenly, and letting it stand for 2 hours to obtain a premixed solution;

[0057] S2. The premixed solution was centrifuged at 3000 rpm for 5 minutes, and the supernatant was filtered to achieve solid-liquid separation. The obtained solid phase product was washed three times with deionized water, and ultrasonic dispersion was performed during each washing. The solid phase product was then centrifuged at 3000 rpm for 5 minutes. The obtained centrifuged product was frozen at -40°C for 24 hours, and finally placed in a freeze dryer and dried under vacuum and low temperature conditions to obtain a sulfide iron oxide catalyst.

[0058] 2. Application of iron sulfide oxide catalyst in the treatment of phenol-containing wastewater

[0059] The above-mentioned iron sulfide oxide catalyst (added amount 0.5 g / L) was mixed with 40 mL of a phenol wastewater solution (the phenol concentration in the phenol wastewater solution was 1.05 g / L and the COD concentration was 5000 mg / L). The pH value of the solution was adjusted to 3.2 with concentrated sulfuric acid to obtain a mixed solution. 39 mmol / L of hydrogen peroxide was added to the mixed solution. After mixing evenly, the phenol removal rate in the phenol wastewater could reach 78% within 3 hours, and the COD removal rate reached 78%.

[0060] Example 5

[0061] 1. Preparation of Iron Sulfide Oxide Catalyst

[0062] S1, dissolving 0.1112 g of ferrous sulfate heptahydrate in 40 mL of deionized water to obtain a ferrous inorganic salt solution, dissolving 0.3666 g of sodium sulfide nonahydrate in 40 mL of deionized water to obtain a sulfur-containing inorganic salt solution, and dissolving 0.0936 g of calcium peroxide in 40 mL of deionized water to obtain an oxygen-containing compound solution; pouring the ferrous inorganic salt solution and the sulfur-containing inorganic salt solution into the oxygen-containing compound solution, stirring evenly, and letting it stand for 2 hours to obtain a premixed solution;

[0063] S2. The premixed solution was centrifuged at 7000 rpm for 2 minutes, and the supernatant was filtered to achieve solid-liquid separation. The obtained solid phase product was washed three times with deionized water, and ultrasonic dispersion was performed during each washing. The solid phase product was then centrifuged at 7000 rpm for 2 minutes. The obtained centrifuged product was frozen at -60°C for 15 hours, and finally placed in a freeze dryer and dried under vacuum and low temperature conditions to obtain a sulfide iron oxide catalyst.

[0064] 2. Application of iron sulfide oxide catalyst in the treatment of phenol-containing wastewater

[0065] The above-mentioned iron sulfide oxide catalyst (added amount 2 g / L) was mixed with 40 mL of a phenol wastewater solution (the phenol concentration in the phenol wastewater solution was 1.89 g / L and the COD concentration was 9000 mg / L). The pH value of the solution was adjusted to 4.0 using concentrated sulfuric acid to obtain a mixed solution. 70 mmol / L of hydrogen peroxide was added to the mixed solution. After mixing evenly, the phenol removal rate in the phenol wastewater could reach 80% within 3 hours, and the COD removal rate reached 80%.

[0066] Example 6

[0067] The difference between this embodiment and embodiment 1 is that the molar concentration ratio of divalent sulfur to iron in the premixed solution is 3:0.05; other steps and parameter settings are consistent with embodiment 1.

[0068] Example 7

[0069] The difference between this embodiment and embodiment 1 is that the molar concentration ratio of divalent sulfur to iron in the premixed solution is 5:3; other steps and parameter settings are consistent with those in embodiment 1.

[0070] Example 8

[0071] The difference between this embodiment and embodiment 1 is that during the aging process, the mixed solution is heated to 35° C.; other steps and parameter settings are consistent with those in embodiment 1.

[0072] Example 9

[0073] The difference between this embodiment and embodiment 1 is that the oxidant is peroxydisulfate; other steps and parameter settings are consistent with those in embodiment 1.

[0074] Example 10

[0075] The difference between this embodiment and embodiment 1 is that the pH value of the mixed solution is 2.5; other steps and parameter settings are consistent with those in embodiment 1.

[0076] Example 11

[0077] The difference between this embodiment and embodiment 1 is that the pH value of the mixed solution is 5.5; other steps and parameter settings are consistent with those in embodiment 1.

[0078] Comparative Example 1

[0079] The difference between this comparative example and Example 1 is that no oxygen-containing compound solution is used in the process of preparing the premix solution; other steps and parameter settings are consistent with Example 1.

[0080] Comparative Example 2

[0081] The difference between this comparative example and Example 1 is that the molar ratio of divalent sulfur to oxygen in the premixed solution is 0.4:0.6; other steps and parameter settings are consistent with Example 1.

[0082] Comparative Example 3

[0083] The difference between this comparative example and Example 1 is that, in the process of treating phenol-containing wastewater, an equal weight of ferroferric oxide Fe3O4 is used instead of the iron sulfide oxide catalyst in Example 1; other steps and parameter settings are consistent with Example 1.

[0084] Test Method

[0085] 1. Phenol removal rate test

[0086] The phenol removal rate of the iron sulfide oxide catalysts prepared in the above examples and comparative examples in phenol wastewater was tested. The specific test steps are as follows: during the reaction, 1 mL of sample was taken at predetermined time intervals, and an excess of ascorbic acid was added to terminate the reaction. The supernatant was then centrifuged and used for subsequent pollutant concentration monitoring (using HPLC) to obtain the phenol removal rate in the phenol wastewater.

[0087] 2. COD removal rate test

[0088] The COD removal efficiency of the iron sulfide oxide catalysts prepared in the above examples and comparative examples was tested. The specific testing steps were as follows: a certain amount of the reaction suspension was filtered through a 0.22 µm PTFE filter membrane. 2 mL of the filtrate was collected as the test sample. A COD reagent consisting of 1 mL of potassium dichromate solution (0.16 M, in a 10% (v / v) H₂SO₄ / H₂O) solution, 0.5 mL of mercuric sulfate solution (100 g / L, in a 10% (v / v) H₂SO₄ / H₂O) solution, and 4 mL of silver sulfate solution (10 g / L, in concentrated sulfuric acid) was added to the 2 mL test sample. The mixture was then digested (165°C, 30 min). Finally, the digested solution, cooled to room temperature, was measured for absorbance using a UV-visible spectrophotometer at a wavelength of 440 nm.

[0089] Table 1

[0090]

[0091] In combination with Examples 1-5, Comparative Examples 1-3 and Table 1, it can be seen that the sulfide iron oxide catalyst prepared by selecting a ferrous inorganic salt solution, a sulfur-containing inorganic salt solution and an oxygen-containing compound solution in the present application can efficiently remove phenol and COD from phenol-containing wastewater; the sulfide iron oxide catalyst has a high phenol removal rate and COD removal rate in phenol-containing wastewater in simulated industrial wastewater, both of which can reach about 85%; in actual industrial wastewater, such as in Example 2, the sulfide iron oxide catalyst has a phenol removal rate and COD removal rate of about 80% for phenol-containing wastewater, and a sulfide iron oxide catalyst has a phenol removal rate and COD removal rate of about 70% for phenol-containing wastewater, which are much higher than the phenol removal rate and COD removal rate in Comparative Examples 1-3. It is worth noting that in Example 2, the COD concentration in the phenol wastewater was 7000 mg / L, and the COD removal rate of the sulfide iron oxide catalyst was as high as 80%. In Example 3, the COD concentration in the phenol wastewater was 6000 mg / L, and the COD removal rate of the sulfide iron oxide catalyst was 72%, which was lower than 80% in Example 2. This may be because when the amount of oxidant is sufficient and the concentration is within an appropriate range, the reaction kinetics are accelerated (the collision frequency increases) or the mass transfer and oxidant utilization can be optimized.

[0092] When an equal weight of ferroferric oxide Fe3O4 is used to replace the sulfide iron oxide catalyst in the present application, the phenol removal rate and COD removal rate in the simulated industrial wastewater and phenol-containing wastewater are greatly reduced, indicating that the sulfide iron oxide catalyst in the present application can efficiently remove phenol and COD in phenol wastewater.

[0093] In combination with Examples 1, 6-7 and Table 1, it can be seen that when the molar ratio of divalent sulfur to iron in the premixed solution is controlled to meet (3-5): (0.05-3), the prepared iron-sulfur oxide catalyst can remove high-concentration organic pollutants in phenol wastewater while only requiring the addition of a very small amount of oxidant to achieve efficient purification of the wastewater.

[0094] Combining Examples 1 and 8 with Table 1, it can be seen that when the aging temperature increases, the phenol removal rate and COD removal rate of the iron sulfide oxide catalyst for phenol wastewater are increased; this is because, during the crystal growth process, the increase in temperature may increase the solubility of some substances, causing the precipitated solids to re-dissolve, hindering aging, and thus affecting the performance of the iron sulfide oxide catalyst finally prepared.

[0095] Combining Examples 1 and 9 with Table 1, it can be seen that when peroxydisulfate is used as an oxidant, the phenol removal rate and COD removal rate of the iron sulfide oxide catalyst in phenol wastewater are greatly reduced; this is because the iron sulfide oxide catalyst in this application cannot fully activate peroxydisulfate and cannot effectively stimulate DOTP.

[0096] In combination with Examples 1, 10-11 and Table 1, it can be seen that when using a sulfide iron oxide catalyst to treat phenol-containing wastewater, the pH value of the mixed solution should be regulated, which can synergistically optimize the surface properties of the sulfide iron oxide catalyst, promote the effective utilization of H2O2, and improve the adsorption and reaction activity of phenol, thereby improving the degradation efficiency of the heterogeneous catalytic system.

[0097] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the technical solutions of the present application can be modified or replaced by equivalents, but these modifications or replacements are all within the scope of protection of the present application.

Claims

1. A method for preparing a sulfide iron oxide catalyst, characterized in that: The steps include: Mixing a ferrous inorganic salt solution, a sulfur-containing inorganic salt solution and an oxygen-containing compound solution to obtain a premixed solution, aging the solution, and obtaining a solid phase product, which is the sulfide-iron oxide catalyst; The oxygen-containing compound solution includes calcium peroxide; Wherein, the molar concentration ratio of divalent sulfur and oxygen in the premixed solution is (0.5-1): (0.01-0.5); The molar concentration ratio of divalent sulfur and iron in the premixed solution is (3-5): (0.05-3); The ferrous inorganic salt in the ferrous inorganic salt solution includes at least one of ferrous sulfate heptahydrate and ferrous chloride, and the concentration of ferrous ions in the premix solution is 0.1-2 mmol / L; The sulfur inorganic salt in the sulfur-containing inorganic salt solution includes sodium sulfide nonahydrate, and the concentration of sulfur ions in the premixed solution is 0.1-2 mmol / L The concentration of peroxide ions in the premix solution is 0.1-2 mmol / L.

2. The method for preparing the iron sulfide oxide catalyst according to claim 1, wherein: During the aging process, the premixed solution was allowed to stand at 20-25° C. for 1.5-3 h.

3. The method for preparing the iron sulfide oxide catalyst according to claim 1, wherein: After aging, the premixed solution is further subjected to a step including freeze drying to obtain the iron sulfide oxide catalyst; The temperature during the freeze-drying process is -60°C to -40°C, and the time is 15-24 hours.

4. A sulfide iron oxide catalyst, characterized in that: The method is prepared by any one of claims 1 to 3.

5. Use of the iron sulfide oxide catalyst prepared by the method according to any one of claims 1 to 3, characterized in that: Used to treat phenol-containing wastewater.

6. The use according to claim 5, characterized in that: The method for treating phenol-containing wastewater comprises the following steps: mixing the iron sulfide oxide catalyst with the phenol-containing wastewater and adjusting the pH value to obtain a mixed solution; adding an oxidant to the mixed solution to obtain treated phenol wastewater; Wherein, the pH value of the mixed solution is 3.2-4.0; The COD concentration in the phenol wastewater is 5000-9000 mg / L, and the phenol concentration is 1.05-1.89 g / L.

7. The use according to claim 6, characterized in that: The concentration of the oxidant in the mixed solution is 39-98 mmol / L; The amount of the iron sulfide oxide catalyst added to the mixed solution is 0.2-2 g / L.

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