Treatment method of cold-rolled acid regenerated desiliconized sludge, catalyst and application of cold-rolled acid regenerated desiliconized sludge

Abstract

The invention discloses a treatment method of cold-rolled acid regenerated desiliconized sludge, a catalyst and application of the catalyst, and belongs to the technical field of desiliconized sludge resource utilization. The method comprises the steps that pretreated desiliconized sludge serves as a carrier, copper and manganese compound precursors are loaded on the surface of the desiliconized sludge, loaded desiliconized sludge is obtained, and an iron source contained in the pretreated desiliconized sludge is beta-type iron oxyhydroxide; and calcining the loaded desiliconized sludge so as to convert the compound precursor of copper and manganese into CuMn2O4 spinel and convert the beta-type iron oxyhydroxide into alpha-Fe2O3, thereby obtaining the catalyst taking the desiliconized sludge as the carrier. According to the scheme, the desilicication sludge is pretreated, then CuMn2O4 spinel is generated in situ in the desilicication sludge, the catalyst is prepared, and resource utilization of the desilicication sludge is achieved. Meanwhile, the catalyst has excellent catalytic performance in Fenton reaction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of desilication sludge resource utilization, more particularly to a treatment method of cold-rolling acid regenerated desilication sludge, a catalyst and application thereof. BACKGROUND

[0002] In the cold rolling process of a steel plant, waste acid is generated after hydrochloric acid pickling of steel plates, and desilication sludge is generated after the desilication process of the waste acid regeneration station. The main components of the desilication sludge are iron oxides, silicon oxides and residual hydrochloric acid, which are classified as hazardous waste due to its strong acidity. A single large cold rolling plant discharges about ten thousand tons of desilication sludge per year. If direct landfill treatment is performed, not only the environment will be polluted, but also serious resource waste will be caused.

[0003] There are relatively few studies on the resource utilization of desilication sludge. For example, Sheng Guanghong et al. published an article entitled "Adsorption Behavior of Desilication Sludge on Fluoride Ions" in the Journal of Safety and Environment, Vol. 5, 1997-2005, May 24, 2024. The article describes that based on the characteristics of iron elements in desilication sludge mainly existing in the form of hydroxyl iron oxide, the desilication sludge is prepared into an iron-based adsorbent by oxidation and water washing method for removing fluoride ions in water. It discloses a specific way of resource utilization of desilication sludge.

[0004] For another example, Ding Xilou et al. published an article entitled "Preparation of Polymeric Ferric Chloride from Desilication Sludge and Experimental Study on Its Modification" in Applied Chemical Industry, Vol. 4, 711-714, 720, April 2016. The article proposes to use desilication sludge as raw material to prepare polymeric ferric chloride flocculant for advanced treatment of coking wastewater. The results show that the removal rates of COD and colority of polymeric aluminum ferric chloride prepared by attapulgite modifier are 70% and 59.53% respectively, which are significantly better than those of unmodified product (54.17% and 45.46% respectively), and the results confirm that the modification treatment can effectively improve the pollutant removal performance of the flocculant.

[0005] Existing patents also disclose some research on resource utilization of desilication sludge by other means, which will not be listed here. The existing technology has not disclosed the use of the above desilication sludge for preparing Fenton reaction catalyst. SUMMARY

[0006] 1. Technical problem to be solved The present application provides a treatment method of cold-rolling acid regenerated desilication sludge, a catalyst and application thereof. The scheme pre-treats the silicon-containing sludge, and generates CuMn2O4 spinel in situ to prepare a catalyst with desilication sludge as a carrier, realizes the resource utilization of desilication sludge, and the added value of this utilization method is high. At the same time, the catalyst has excellent catalytic performance in Fenton reaction.

[0007] 2. Technical solutions adopted To achieve the above objectives, the technical solution provided by this invention is as follows: The first aspect of this invention provides a method for treating cold-rolled acid-regenerated desilication sludge, comprising: using pretreated desilication sludge as a carrier, loading copper and manganese compound precursors onto the surface of the desilication sludge to obtain loaded desilication sludge, wherein the iron source contained in the pretreated desilication sludge is β-type iron hydroxide; calcining the loaded desilication sludge to convert the copper and manganese compound precursors into CuMn2O4 spinel and the β-type iron hydroxide into α-Fe2O3, thereby obtaining a catalyst with desilication sludge as a carrier.

[0008] It should be noted that this invention uses desilication sludge as a carrier for catalyst preparation for the following reasons: Firstly, the mass percentage of SiO2 in desilication sludge is approximately 20-30%, mainly existing in the form of amorphous silica. Simultaneously, the desilication sludge contains a large amount of iron oxides, which function as both a carrier matrix and active sites, thus eliminating the need for additional iron sources. Silica and iron oxides together form a porous framework with a high specific surface area, providing highly dispersed anchoring sites for the loading of Cu and Mn pairs. Subsequently, during calcination, this provides highly dispersed anchoring sites for the generated CuMn2O4, effectively inhibiting nanoparticle aggregation. Secondly, the formation of CuMn2O4 during calcination inhibits and refines the grain growth of the original iron oxides in the sludge, successfully controlling the particle size of α-Fe2O3 in the system from approximately 20 nm under direct calcination conditions to below 10 nm. In summary, by combining the structural support of amorphous silica with the synergistic effect of α-Fe2O3 and CuMn2O4, a highly dispersed dual nanocomposite system of α-Fe2O3 and CuMn2O4 was successfully constructed, which significantly increased the number of active sites and improved the interfacial electron transport efficiency.

[0009] This invention uses desilication sludge as raw material to prepare catalysts from this solid waste, thereby increasing the added value of solid waste recycling.

[0010] Furthermore, the loading of copper and manganese compound precursors onto the surface of the desilication sludge specifically involves: mixing a 0.05-0.1 mol / L soluble copper salt solution, a 0.05-0.1 mol / L soluble manganese salt solution, and the pretreated desilication sludge to obtain a mixed salt solution, wherein the molar ratio of Cu²⁺ to Mn²⁺ in the mixed salt solution is 1:1-2; then adjusting the mixed salt solution to alkaline; wherein the desilication sludge used is dried sludge, and Cu²⁺ is added per gram of desilication sludge. 2+ and Mn 2+The total molar amount is 2-3 mmol. By limiting the concentration of the used soluble copper salt solution and the soluble manganese salt solution, compared with the soluble metal salt solution with too high concentration, the soluble manganese salt solution with the concentration is more conducive to the formation of the required crystal. At the same time, by limiting the molar ratio of Cu 2+ and Mn 2+ , it is ensured that there is enough Cu element for the generation of CuMn2O4.

[0011] Further, the mixed salt solution is adjusted to be alkaline, specifically, the pH value is adjusted to 9.5-10.0 by using an alkali solution, stirring at 300-500 r / min for 1-2 h, and aging at 30-50℃ for 2-3 h.

[0012] Further, the desilicated sludge after loading is calcined, specifically, the calcination temperature is 400-500℃, and the calcination time is 2-4 h. If the calcination temperature is too low, it may lead to incomplete crystal structure of the formed copper manganese spinel; on the contrary, if the temperature is too high, it will lead to too dense structure of the generated copper manganese spinel and α-Fe2O3, thereby reducing the catalytic activity. Therefore, within the above-mentioned calcination temperature range, it is conducive to ensuring that the obtained product has good catalytic performance.

[0013] Further, the desilicated sludge after loading is sequentially subjected to drying, crushing, then calcination, and water washing of the calcined desilicated sludge. Among them, the crushing treatment before calcination is conducive to the uniformity of the subsequent calcined product, thereby being conducive to building an ideal pore structure with high activity and high stability. If crushing treatment is not performed before calcination, the size of the calcined material may be large, which may lead to surface hardening and internal mass transfer unevenness, thereby leading to a decrease in the number of active sites of the catalyst and a decrease in mass transfer efficiency.

[0014] Further, the pretreatment of the desilicated sludge is specifically: using 1-3wt% hydrogen peroxide solution to oxidize the desilicated sludge, the solid-liquid ratio of the desilicated sludge to hydrogen peroxide is 1g:5-10ml, wherein the desilicated sludge used is dried sludge, the stirring speed during the reaction process is 300-500r / min, and the time is 1-3h, to oxidize the desilicated sludge.

[0015] Further, the desilicated sludge is subjected to water washing after oxidation treatment, the water washing is performed until the content of chloride ions is <0.05%, and then drying is performed.

[0016] The second aspect of the application provides a catalyst, which uses desilicated sludge as a carrier, the iron source contained therein exists in the form of α-Fe2O3 and the particle size is ≤10nm, and CuMn2O4 spinel is loaded thereon, the mass ratio of CuMn2O4 to the mass of the desilicated sludge carrier is 10-20%.

[0017] Further, the catalyst is prepared by the treatment method of the cold-rolled acid regeneration desilication sludge described above.

[0018] The third aspect of the application provides a use of the catalyst as a heterogeneous Fenton reaction catalyst, and the catalyst mixed with H2O2 can be used for degrading tetracycline hydrochloride.

[0019] It should be further noted that the internal microstructure of the catalyst can be known through the above description, and the efficient multi-metal electron transfer network is formed through the close interface contact between nano α-Fe2O3 and nano CuMn2O4 spinel. This structure can effectively accelerate the activation kinetics process of H2O2, especially by strengthening the cyclic regeneration of Fe 3+ / Fe 2+ , which effectively breaks through the rate-limiting step of the traditional Fenton-like reaction. In the synergistic system, the rapid electron circulation of Cu + / Cu 2+ , the wide pH adaptability of Mn multi-valence (Mn 2+ / Mn 3+ / Mn 4+ ), and the efficient ·OH generation capacity of Fe 2+ / Fe 3+ work together to build a multi-component and efficient reactive oxygen species (ROS) generation system, so as to realize efficient degradation of refractory organic matter in a wide pH range and exhibit excellent catalytic stability. In addition, the catalyst has good recovery of catalytic performance after regeneration.

[0020] Compared with the prior art, the technical scheme provided by the application has the following beneficial effects: (1) The application is based on in-depth research on the resource utilization method of desilication sludge. Specifically, the iron source contained therein is pretreated to be β-type hydroxyl iron oxide; thereby the silicon dioxide and iron oxide together form a porous framework with a high specific surface area, providing highly dispersed anchoring sites for the loading of Cu and Mn; and then nano α-Fe2O3 and CuMn2O4 dispersed in the silicon dioxide matrix are generated in the calcination process, significantly increasing the number of active sites of the obtained catalyst and improving the interface electron transport efficiency, so as to improve the catalytic performance of the catalyst.

[0021] (2) The present application optimizes the process parameters in the calcination process, specifically, the calcination temperature is selected at 400-500℃. If the calcination temperature is too low, the crystal structure of the copper manganese spinel formed may not be complete; on the contrary, if the temperature is too high, it may cause the copper manganese spinel and α-Fe2O3 structure generated to be too dense, thereby reducing its catalytic activity. By calcining in the above temperature range, the balance of "complete decomposition" and "structure stability" of the catalyst precursor can be achieved, which is not only beneficial to the construction of a porous structure for mass transfer, but also inhibits the sintering of the carrier, so that the active components loaded can exist in a high dispersion and high activity state, thereby ensuring that the obtained product has good catalytic performance.

[0022] (3) The present application further optimizes the process of loading copper and manganese compound precursors on the surface of the desilicated sludge, specifically, the molar ratio of Cu 2+ and Mn 2+ in the mixed salt solution is 1:1-2; not only enough Cu elements are ensured for the generation of CuMn2O4, but also the moderately remaining copper can form highly dispersed CuO at the interface, thereby optimizing the interface electron transport and catalytic performance. In addition, the total molar amount of Cu 2+ and Mn 2+ added per gram of dried desilicated sludge is 2-3mmol, and the catalytic performance of the prepared catalyst is better under this addition amount. Further, the desilicated sludge after loading is sequentially dried, crushed, and then calcined, and the crushing treatment before calcination is beneficial to the uniformity of the subsequent calcined product, thereby being beneficial to the construction of an ideal pore structure with high activity and high stability. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the micro-morphology diagram of the catalyst prepared in Example 1 of the present application.

[0024] Figure 2 It is the XRD pattern of the catalyst prepared in Example 1 of the present application, calcined sludge and pretreated desilicated sludge.

[0025] Figure 3 It is a schematic diagram of the cyclic use performance and regeneration performance of the catalyst prepared in Example 1 of the present application.

[0026] Figure 4 It is the XRD pattern of the catalyst prepared in Example 1 of the present application before and after adsorption.

[0027] Figure 5 It is the removal rate of TCH of the catalyst prepared in Example 1 and Comparative Examples 1-3 of the present application.

[0028] Figure 6The removal rate of TCH at different concentrations by the catalyst prepared in Example 2 of this invention.

[0029] Figure 7 The TCH removal rate of the catalyst prepared in Example 2 of this invention at different initial pH values.

[0030] Figure 8 This is a microscopic morphology diagram of the pretreated desilication sludge obtained in Example 1 of the present invention. Detailed Implementation

[0031] To further understand the content of the present invention, the present invention will be described in detail with reference to embodiments and comparative examples.

[0032] The following process involves dewatering desiliconized sludge, pretreated desiliconized sludge, or loaded desiliconized sludge, which can be done using centrifugal dewatering machines, plate and frame filter presses, or belt dewatering machines.

[0033] The following process involves oxidizing the sludge. This can be done using hydrogen peroxide solution, aeration, or ozone. Following this, the oxidized sludge is washed, dewatered, and dried.

[0034] In the following implementation process, the mixed salt solution is adjusted to alkalinity. Not only sodium carbonate solution, but also ammonium carbonate solution, sodium hydroxide solution or ammonia water can be used.

[0035] The soluble copper and manganese salts used in the following procedures can be not only nitrates, but also other soluble copper and manganese salts.

[0036] Example 1 This embodiment provides a method for treating cold-rolled acid regeneration desilication sludge, the method comprising: S1. Oxidation treatment of desiliconized sludge: Mix 1g of desiliconized sludge with 1wt% hydrogen peroxide solution at a solid-liquid ratio of 1g:8ml. The desiliconized sludge used is dried sludge. The stirring speed is 500 / min and the reaction time is 3h. Then, wash with distilled water 8 times until the chloride ion content is <0.05%. Dehydrate the deoxidized desiliconized sludge using a centrifugal dewatering machine. Then, dry it in an air drying oven at 80℃ for 4h to obtain pretreated dried desiliconized sludge.

[0037] S2. Loading the pretreated dried desilication sludge: Mix a 0.05 mol / L copper nitrate solution, a 0.1 mol / L manganese nitrate solution, and the pretreated desilication sludge obtained in S1 thoroughly to obtain a mixed salt solution. The Cu in the obtained mixed salt solution... 2+ With Mn 2+The molar ratio is 1:2; wherein, the desilication sludge used is dried sludge, and the Cu used per gram of dried desilication sludge is... 2+ and Mn 2+ The total molar amount was 3 mmol; then 0.2 mol / L sodium carbonate solution was added dropwise until the solution pH value was 9.6, stirred at 500 r / min for 1 h at room temperature, and allowed to stand and age for 2 h at 40℃ to obtain the desiliconized sludge after loading.

[0038] S3. The desiliconized sludge obtained after loading in S2 was dehydrated using a centrifugal dewatering machine and then dried at 70°C for 5 hours in an air drying oven. Subsequently, it was crushed into particles of 0.1~0.2 mm and calcined at 400°C for 3 hours in an air atmosphere. The calcined product was washed with distilled water until the pH of the washing liquid was close to neutral. After drying, the copper-manganese-desiliconized sludge heterogeneous Fenton catalyst was obtained.

[0039] The microstructure of the pretreated desilication sludge obtained in S1 in this embodiment is shown in the figure below. Figure 8 As shown, the sludge exhibits a flocculent aggregate morphology, with the flocculent material encapsulating needle-like crystals. XRD analysis suggests that this flocculent material is amorphous SiO2. The flocculent material on the surface of the desilication sludge increases its specific surface area, which is beneficial for adsorbing pollutants. Simultaneously, the study also observed needle-like β-FeOOH crystals coated on the surface of the amorphous SiO2. The β-FeOOH and amorphous SiO2 mutually encapsulate and adhere to each other, resulting in an irregular morphology for the desilication sludge.

[0040] The catalyst prepared in this embodiment is designated as CuMn2O4-desiliconized sludge catalyst. The macroscopic morphology of this catalyst is that of near-spherical particles with a specific surface area of ​​57.4 m². 2 / g, its microstructure diagram is as follows Figure 1 As shown, from Figure 1 As can be seen, each spherical particle is composed of a large number of radially or interwoven fibrous aggregates. The main trunk and branches of these fibrous aggregates are mainly composed of desilication sludge carriers. These fibrous aggregate structures are further composed of cross-linked and assembled smaller nanoscale primary particles. Among them, copper-manganese spinel is mainly attached to the desilication sludge in the form of nanoparticles. The catalyst's internal structure forms abundant and open pore channels through a hierarchical construction mode of "nanoscale primary particles → fibrous secondary aggregates → spherical tertiary microspheres," thereby enabling a highly efficient mass transfer process.

[0041] The XRD pattern of the catalyst is as follows: Figure 2 As shown, from Figure 2 As can be seen from the figure, the iron source contained therein forms nano-α-Fe2O3 after calcination, and its particle size is calculated to be less than 10 nm according to the Scherrer equation.

[0042] Comparative Example 1 This comparative example provides a method for treating cold-rolled acid regeneration desilication sludge, which differs from Example 1 in that: the pretreated desilication sludge obtained in S1 is directly calcined; the loading treatment in S2 is not performed, and the remaining operations are basically the same, and a catalyst is prepared, which is referred to as the calcined sludge catalyst.

[0043] The XRD pattern of the catalyst prepared in this comparative example is as follows: Figure 2 As shown, from Figure 2 As can be seen from the figure, the catalyst obtained from the calcined sludge has a relatively large particle size, approximately 20 nm.

[0044] Comparative Example 2 This comparative example provides a method for treating cold-rolled acid-regenerated desilication sludge, which differs from Example 1 in that the loading process in S2 is different. Specifically, in S2, only a 0.05 mol / L copper nitrate solution is mixed evenly with the pretreated desilication sludge obtained in S1 to obtain a mixed salt solution. That is, the obtained mixed salt solution only contains copper nitrate and does not include manganese nitrate. The Cu used per gram of dried desilication sludge is... 2+ The molar amount was 3 mmol; the rest of the operation was basically the same, and the catalyst was prepared, which was denoted as Cu-desiliconized sludge catalyst.

[0045] Comparative Example 3 This comparative example provides a method for treating cold-rolled acid-regenerated desilication sludge, which differs from Example 1 in that the loading process in S2 is different. Specifically, in S2, only a 0.1 mol / L manganese nitrate solution is mixed evenly with the pretreated desilication sludge obtained in S1 to obtain a mixed salt solution. That is, the obtained mixed salt solution contains only manganese nitrate and does not include copper nitrate. The amount of Mn used per gram of dried desilication sludge is specified. 2+ The molar amount was 3 mmol; the rest of the operation was basically the same, and the catalyst was prepared, which was denoted as Mn-desiliconized sludge catalyst.

[0046] Comparative Example 4 This comparative example provides a method for treating cold-rolled acid regeneration desilication sludge, which differs from Example 1 in that the loading process in S2 is different. Specifically, Cu in the mixed salt solution obtained in S2... 2+ With Mn 2+ The molar ratio is 1:3, and the Cu used per gram of dried desilication sludge is... 2+ and Mn 2+ The total molar amount was 4 mmol; the remaining operations were basically the same, and the catalyst was prepared.

[0047] Comparative Example 5 This comparative example provides a method for treating cold-rolled acid regeneration desilication sludge, which differs from Example 1 in that the loading process in S2 is different. Specifically, Cu in the mixed salt solution obtained in S2... 2+ With Mn 2+ The molar ratio is 1.2:1, and the Cu used per gram of desilication sludge is... 2+ and Mn 2+ The total molar amount was 4 mmol; the remaining operations were basically the same, and the catalyst was prepared.

[0048] Comparative Example 6 This comparative example provides a method for treating cold-rolled acid regeneration desilication sludge. The difference between this method and Example 1 is that the calcination temperature in S3 is different. Specifically, the calcination temperature in S3 is 350°C. The remaining operations are basically the same, and a catalyst is prepared.

[0049] Comparative Example 7 This comparative example provides a method for treating cold-rolled acid regeneration desilication sludge. The difference between this method and Example 1 is that the calcination temperature in S3 is different. Specifically, the calcination temperature in S3 is 550°C. The remaining operations are basically the same, and a catalyst is prepared.

[0050] Example 2 This embodiment provides a method for treating cold-rolled acid-regenerated desilication sludge. The method includes: S1, oxidizing the desilication sludge: mixing 1g of desilication sludge with 1wt% hydrogen peroxide solution at a solid-liquid ratio of 1g:10ml, wherein the desilication sludge used is dried sludge, the reaction time is 3h, the stirring speed is 300r / min, and then washing it 6 times with distilled water until the chloride ion content is <0.05%, dewatering the deoxidized desilication sludge using a centrifugal dewatering machine, and then drying it in an air drying oven at 60℃ for 6h to obtain pretreated dried desilication sludge.

[0051] S2. Loading the pretreated dried desilication sludge: Mix a 0.05 mol / L copper nitrate solution, a 0.05 mol / L manganese nitrate solution, and the pretreated desilication sludge obtained in S1 thoroughly to obtain a mixed salt solution. The Cu in the obtained mixed salt solution... 2+ With Mn 2+ The molar ratio is 1:1; wherein the desilication sludge used is dried sludge, and the Cu used per gram of dried desilication sludge is... 2+ and Mn 2+ The total molar amount was 2 mmol; then 0.1 mol / L sodium carbonate solution was added dropwise until the solution pH value was 9.5, stirred at 300 r / min for 1 h at room temperature, and allowed to stand and age at 30℃ for 2 h to obtain the desiliconized sludge after loading.

[0052] S3. The desiliconized sludge obtained after loading in S2 was dehydrated using a centrifugal dewatering machine and then dried at 60°C for 6 hours in an air drying oven. Subsequently, it was crushed into particles of 0.1~0.2 mm and calcined at 400°C for 3 hours in an air atmosphere. The calcined product was washed with distilled water until the pH of the washing liquid was close to neutral. After drying, the copper-manganese-desiliconized sludge heterogeneous Fenton catalyst was obtained.

[0053] The catalyst prepared in this embodiment has a specific surface area of ​​43.8 m² / g.

[0054] Example 3 This embodiment provides a method for treating cold-rolled acid regeneration desilication sludge, the method comprising: S1. Oxidation treatment of desilication sludge: Mix 1g of desilication sludge with 2wt% hydrogen peroxide solution at a solid-liquid ratio of 1g:8ml, wherein the desilication sludge is in the state of dried sludge, the reaction time is 2h, the stirring speed is 400r / min, and then wash with distilled water 8 times until the chloride ion content is <0.05%. Dehydrate the deoxidized desilication sludge using a centrifugal dewatering machine, and then dry it in an air drying oven at 90℃ for 3h to obtain pretreated dried desilication sludge.

[0055] S2. Loading the pretreated dried desilication sludge: Mix a 0.075 mol / L copper nitrate solution, a 0.075 mol / L manganese nitrate solution, and the pretreated desilication sludge obtained in S1 thoroughly to obtain a mixed salt solution. The Cu in the obtained mixed salt solution... 2+ With Mn 2+ The molar ratio is 1:1; wherein the desilication sludge used is dried sludge, and the Cu used per gram of dried desilication sludge is... 2+ and Mn 2+ The total molar amount was 3 mmol; then 0.2 mol / L sodium carbonate solution was added dropwise until the solution pH value was 10.0, stirred at 400 r / min for 1 h at room temperature, and allowed to stand and age at 50℃ for 2 h to obtain the desiliconized sludge after loading.

[0056] S3. The desiliconized sludge obtained after loading in S2 was dehydrated using a centrifugal dewatering machine and then dried at 100°C for 2 hours in an air drying oven. Subsequently, it was crushed into particles of 0.1~0.2 mm and calcined at 500°C for 3 hours in an air atmosphere. The calcined product was washed with distilled water until the pH of the washing liquid was close to neutral. After drying, the copper-manganese-desiliconized sludge heterogeneous Fenton catalyst was obtained.

[0057] The catalyst prepared in this embodiment has a specific surface area of ​​39.7 m² / g.

[0058] Example 4 This embodiment provides a method for treating cold-rolled acid regeneration desilication sludge, the method comprising: S1. Oxidation treatment of desilication sludge: Mix 1g of desilication sludge with 3wt% hydrogen peroxide solution at a solid-liquid ratio of 1g:5ml, wherein the desilication sludge is in the state of dried sludge, the reaction time is 2h, the stirring speed is 350r / min, and then wash with distilled water 9 times until the chloride ion content is <0.05%. Dehydrate the deoxidized desilication sludge using a centrifugal dewatering machine, and then dry it in an air drying oven at 70℃ for 5h to obtain pretreated dried desilication sludge.

[0059] S2. Loading the pretreated dried desilication sludge: Mix a 0.05 mol / L copper nitrate solution, a 0.1 mol / L manganese nitrate solution, and the pretreated desilication sludge obtained in S1 thoroughly to obtain a mixed salt solution. The Cu in the obtained mixed salt solution... 2+ With Mn 2+ The molar ratio is 1:2; wherein the desilication sludge used is dried sludge, and the Cu used per gram of dried desilication sludge is... 2+ and Mn 2+ The total molar amount was 3 mmol; then 0.1 mol / L sodium carbonate solution was added dropwise until the solution pH value was 9.6, stirred at 400 r / min for 1 h at room temperature, and allowed to stand and age at 30℃ for 2 h to obtain the desiliconized sludge after loading.

[0060] S3. The desiliconized sludge obtained after loading in S2 was dehydrated using a centrifugal dewatering machine and then dried at 100°C for 6 hours in an air drying oven. Subsequently, it was crushed into particles of 0.1~0.2 mm and calcined at 400°C for 4 hours in an air atmosphere. The calcined product was washed with distilled water until the pH of the washing liquid was close to neutral. After drying, the copper-manganese-desiliconized sludge heterogeneous Fenton catalyst was obtained.

[0061] The catalyst prepared in this embodiment has a specific surface area of ​​55.1 m² / g.

[0062] Example 5 This embodiment provides a method for treating cold-rolled acid regeneration desilication sludge, the method comprising: S1. Oxidation treatment of desilication sludge: Mix 1g of desilication sludge with 2wt% hydrogen peroxide solution at a solid-liquid ratio of 1g:10ml, wherein the desilication sludge is in the state of dried sludge, the reaction time is 2.5h, the stirring speed is 400r / min, and then wash with distilled water 9 times until the chloride ion content is <0.05%. Dehydrate the deoxidized desilication sludge using a centrifugal dewatering machine, and then dry it in an air drying oven at 70℃ for 5h to obtain pretreated dried desilication sludge.

[0063] S2. Loading the pretreated dried desilication sludge: Mix a 0.05 mol / L copper nitrate solution, a 0.075 mol / L manganese nitrate solution, and the pretreated desilication sludge obtained in S1 thoroughly to obtain a mixed salt solution. The Cu in the obtained mixed salt solution... 2+ With Mn 2+ The concentrations were 0.05 mol / L and 0.075 mol / L, respectively, Cu 2+ With Mn 2+ The molar ratio is 1:1.5; where the Cu used per gram of dried desilication sludge is... 2+ and Mn 2+ The total molar amount was 2.5 mmol; then 0.1 mol / L sodium carbonate solution was added dropwise until the solution pH value was 10, stirred at 400 r / min for 2 h at room temperature, and then allowed to stand and age for 3 h at 30 ℃ to obtain the desiliconized sludge after loading.

[0064] S3. The desiliconized sludge obtained after loading in S2 was dehydrated using a centrifugal dewatering machine and then dried in an air drying oven at 80°C for 4 hours. Subsequently, it was ground and calcined at 450°C in air for 2 hours. The calcined powder was washed 8 times with distilled water until the pH of the washing liquid was close to neutral. After drying, the copper-manganese-desiliconized sludge heterogeneous Fenton catalyst was obtained.

[0065] The catalyst prepared in this embodiment has a specific surface area of ​​46.8 m² / g.

[0066] Performance testing Application Example 1 In a conical flask reactor, the concentrations of TCH were 20 mg / L, 40 mg / L, 60 mg / L, 80 mg / L, and 100 mg / L, respectively; the H₂O₂ dosage was 40 mmol / L; and the pH value was 4.3. The CuMn₂O₄-desiliconized sludge catalyst prepared in Example 2 was used at a dosage of 0.3 g / L. The reaction conditions for the heterogeneous Fenton catalyst were: a water bath shaker at a constant temperature of 30°C, a rotation speed of 180 rpm, and a reaction time of 90 min. The removal rate of TCH at different concentrations was analyzed, and the results are shown in [the table below]. Figure 6 As shown.

[0067] Application Example 2 In a conical flask reactor, the concentration of TCH was 40 mg / L, the amount of H₂O₂ was 40 mmol / L, and the initial pH of the wastewater was adjusted to 3, 5, 7, 9, and 11. The CuMn₂O₄-desiliconized sludge catalyst prepared in Example 2 was used at a dosage of 0.3 g / L. The reaction conditions for the heterogeneous Fenton catalyst were: a water bath shaker at a constant temperature of 30°C, a rotation speed of 180 rpm, and a reaction time of 90 min. The TCH removal rate of the catalyst at different initial pH values ​​was analyzed, and the results are shown below. Figure 7 As shown, from Figure 7 As can be seen from this, the catalyst has a wide pH range adaptability.

[0068] Application Example 3 To evaluate the synergistic effect of copper-manganese bimetallic doping, the CuMn2O4-desiliconized sludge catalyst prepared in Example 1 was compared with the catalysts prepared in Comparative Examples 1-3. In addition, a control group was added with only hydrogen peroxide solution added and no catalyst was added.

[0069] In a conical flask reactor, the reaction conditions for the heterogeneous Fenton catalyst were investigated: an initial TCH concentration of 40 mg / L, pH of 4.3, H₂O₂ dosage of 40 mmol / L, and catalyst dosage of 0.3 g / L. The effects of different reaction systems on the TCH removal rate were examined, and the results are as follows: Figure 5 As shown.

[0070] from Figure 5 It can be seen that the catalytic effect of the CuMn2O4-desiliconized sludge catalyst prepared in Example 1 is much higher than that of the control group and the catalysts obtained in Comparative Examples 1-3, indicating that there is a synergistic effect between copper and manganese ions.

[0071] Application Example 4 In the conical flask reactor, the reaction conditions for the heterogeneous Fenton catalyst were as follows: the initial concentration of TCH was set at 40 mg / L, the amount of H2O2 added was 40 mmol / L, the pH value was set at 4.3, and the amount of CuMn2O4-desiliconized sludge catalyst prepared in Example 1 was 0.3 g / L.

[0072] The reaction conditions for the heterogeneous Fenton catalyst were as follows: The reaction was carried out in a constant-temperature water bath shaker at 30°C, with a rotation speed of 180 r / min, for a reaction time of 90 min. After the reaction, the catalyst was recovered and washed, then dried at 60°C for 6 hours. This process was repeated five times to evaluate its reusability; the changes in catalytic performance are shown below. Figure 3 As shown.

[0073] After being reused five times, the catalyst was cleaned and then calcined in air at 400°C for 3 hours to regenerate its activity. The catalytic performance of the regenerated catalyst was then evaluated, and its regenerated performance was as follows: Figure 3 As shown.

[0074] In addition, XRD characterization was performed on samples of the catalyst before and after the first degradation reaction, and the XRD spectra are shown below. Figure 4 As shown in the figure, the XRD pattern of the catalyst after the reaction did not change significantly in terms of the position and intensity of the characteristic peaks compared with that before use. This indicates that the crystal structure of the catalyst remained stable after the first use and no significant phase transition or lattice structure change occurred.

[0075] Application Example 5 Compared with FeSO4, a commonly used catalyst in the Fenton reaction, the catalyst prepared in this invention was subjected to the following reaction conditions for the heterogeneous Fenton catalyst: initial TCH concentration of 40 mg / L, pH value of 4.3, H2O2 dosage of 40 mmol / L, and reaction time of 90 min. Specifically, the experimental group used the CuMn2O4-desiliconized sludge catalyst prepared in Example 1, with a dosage of 0.3 g / L. Three control groups were established, with FeSO4 dosages of 0.3 g / L, 0.5 g / L, and 1.0 g / L, respectively. The H2O2 dosage in all control groups was 40 mmol / L. The TCH removal efficiencies are detailed in Table 1.

[0076]

[0077] Application Example 6 The catalytic effects of the catalysts prepared in Example 1 and Comparative Examples 4-7 were compared. The reaction conditions for the heterogeneous Fenton catalyst were as follows: the initial TCH concentration was set at 40 mg / L, the pH value was set at 4.3, the H2O2 dosage was 40 mmol / L, the reaction time was 90 min, and the amount of catalyst used was 0.3 g / L. The TCH removal efficiency is shown in Table 2.

[0078]

Claims

1. A method for treating cold-rolled acid regeneration desilication sludge, characterized in that, include: Using pretreated desiliconized sludge as a carrier, copper and manganese compound precursors are loaded onto the surface of the desiliconized sludge to obtain loaded desiliconized sludge, wherein the iron source contained in the pretreated desiliconized sludge is β-type iron hydroxyoxide. The desilication sludge after loading is calcined to convert copper and manganese compound precursors into CuMn2O4 spinel and β-type ferric hydroxide into α-Fe2O3, thus obtaining a catalyst with desilication sludge as a support.

2. The method for treating cold-rolled acid regeneration desilication sludge according to claim 1, characterized in that, The loading of copper and manganese compound precursors onto the surface of the desilication sludge specifically involves: A 0.05–0.1 mol / L soluble copper salt solution, a 0.05–0.1 mol / L soluble manganese salt solution, and pretreated desilication sludge were mixed to obtain a mixed salt solution. The mixed salt solution contained Cu… 2+ and Mn 2+ The molar ratio is 1:1~2; then the mixed salt solution is adjusted to alkalinity; wherein, the desilication sludge used is dried sludge, and Cu is added per gram of dried desilication sludge. 2+ and Mn 2+ The total molar amount is 2~3 mmol.

3. The method for treating cold-rolled acid regeneration desilication sludge according to claim 2, characterized in that, The adjustment of the mixed salt solution to alkalinity specifically involves: Adjust the pH value to 9.5~10.0 with an alkaline solution, stir at 300~500 r / min for 1~2 h, and let it stand at 30~50℃ for 2~3 h to age.

4. The method for treating cold-rolled acid regeneration desilication sludge according to claim 1, characterized in that, The calcination of the desilication sludge after loading is specifically carried out at a calcination temperature of 400~500℃ and a calcination time of 2~4h.

5. The method for treating cold-rolled acid regeneration desilication sludge according to claim 4, characterized in that, The desiliconized sludge after loading is successively dried, crushed, calcined, and then washed with water.

6. The method for treating cold-rolled acid regeneration desilication sludge according to any one of claims 1-5, characterized in that, The pretreatment of the desiliconized sludge specifically includes: The desilication sludge was oxidized using a 1-3 wt% hydrogen peroxide solution, wherein the solid-liquid ratio of the desilication sludge to hydrogen peroxide was 1 g: 5-10 ml, and the desilication sludge used was dried sludge. The stirring speed during the reaction was 300-500 r / min, and the time was 1-3 h, in order to oxidize the desilication sludge.

7. The method for treating cold-rolled acid regeneration desilication sludge according to claim 6, characterized in that, The desiliconized sludge is washed with water after oxidation treatment until the chloride ion content is <0.05%, and then dried.

8. A catalyst, characterized in that, The catalyst uses desilication sludge as a carrier, and the iron source it contains exists in the form of α-Fe2O3 with a particle size ≤10nm. CuMn2O4 spinel is loaded on it, and the mass ratio of CuMn2O4 to the mass of the desilication sludge carrier is 10~20%.

9. A catalyst, characterized in that, The catalyst was prepared using the treatment method for cold-rolled acid regeneration desilication sludge as described in any one of claims 1-7.

10. The application of the catalyst as described in claim 8 or claim 9 as a heterogeneous Fenton reaction catalyst, characterized in that, The catalyst, when mixed with H2O2, can be used to degrade tetracycline hydrochloride.

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