A fenton-like catalyst, and a preparation method and application thereof

Abstract

The application provides a Fenton-like catalyst and a preparation method and application thereof. The preparation method of the Fenton-like catalyst comprises the following steps: S1, crushing and calcining dried leaves to obtain a precursor; S2, immersing the precursor in a mixed solution of sodium molybdate and thiourea to obtain an immersion mixed system; S3, stirring the immersion mixed system and then performing a hydrothermal reaction to obtain a hydrothermal reaction product; and S4, washing and drying the hydrothermal reaction product to obtain the Fenton-like catalyst. The Fenton-like catalyst can be used for activating hydrogen peroxide and applied to wastewater treatment of dyes and the like. The Fenton-like catalyst can effectively degrade various organic pollutants in a wide pH range and in the presence of different salt contents, has strong catalytic stability, excellent degradation effect and a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a Fenton-like catalyst and a preparation method and application thereof. BACKGROUND

[0002] In recent years, water pollution has become a global problem that needs to be solved urgently. More and more organic pollutants are detected in natural water bodies, which are mostly persistent and difficult to degrade, and can produce ecological toxicology effects after biological enrichment in natural water bodies, posing a serious threat to public water safety and human health.

[0003] Fenton water treatment technology is to use the reduction of H2O2 to produce a large amount of active oxygen species (ROS) such as hydroxyl radicals (·OH) to attack and degrade organic pollutants. However, there are many defects in the classical Fenton reaction process, for example, the pH needs to be strictly controlled at about 3 during the reaction, when pH>3, Fe 3+ A large amount of precipitate will be produced to form hazardous waste iron sludge which is difficult to handle, and the activity of Fenton reaction will also be seriously affected; a large amount of H2O2 will be decomposed into O2 without effect during the reaction, resulting in very low utilization rate of H2O2 in the reaction system, causing waste of resources. Therefore, it is urgent to develop an efficient Fenton catalyst to solve the above problems.

[0004] In view of this, the present application is proposed. SUMMARY

[0005] The purpose of the present application is to provide a Fenton-like catalyst and a preparation method and application thereof, which can effectively degrade various organic pollutants in a wide pH range and in the presence of different salinity, has strong catalytic stability and excellent degradation effect.

[0006] The present application provides a preparation method of a Fenton-like catalyst, comprising the following steps:

[0007] S1: crushing the dried leaves and then calcining to obtain a precursor;

[0008] S2: immersing the precursor in a mixed solution of sodium molybdate and thiourea to obtain an immersion mixed system;

[0009] S3: stirring the immersion mixed system and then performing a hydrothermal reaction to obtain a hydrothermal reaction product;

[0010] S4: washing and drying the hydrothermal reaction product to obtain the Fenton-like catalyst.

[0011] Specifically, in step S1, the temperature rising rate during the calcination treatment is 5-10℃ / min, preferably 5℃ / min; the calcination treatment temperature is 600-700℃, preferably 700℃; and the calcination treatment time is 1-2h, preferably 1h.

[0012] In step S2, the ratio of the amount of the precursor, sodium molybdate and thiourea is 1g:4-6mmol:8-12mmol, preferably 1g:5mmol:10mmol; and the impregnation time is 1.5-2.5h, preferably 2h.

[0013] In step S3, the temperature during the stirring is 50-70℃, preferably 60℃; the stirring time is 20-30min, preferably 20min; the hydrothermal reaction temperature is 160-200℃, preferably 180℃; and the hydrothermal reaction time is 18-24h, preferably 18h.

[0014] In step S4, the alternating washing is performed with ethanol and deionized water in sequence; the washing times are 3-6, preferably 5; and the drying temperature is 60-80℃, preferably 70℃.

[0015] The application further provides a Fenton-like catalyst prepared according to the above preparation method.

[0016] The application further provides the application of the above Fenton-like catalyst in sewage treatment.

[0017] Specifically, the Fenton-like catalyst and H2O2 are used to degrade and treat the sewage containing organic pollutants. In particular, the amount of the Fenton-like catalyst used in the degradation treatment is 0.2-1.0g / L; and the pH in the degradation treatment is 3-11, preferably pH 3-9.

[0018] The application does not strictly limit the type of the organic pollutants, which include but are not limited to rhodamine B, acid orange 7, methyl orange, etc.

[0019] The implementation of the application has at least the following advantages:

[0020] 1. The application uses tree branches and leaves as raw materials for preparation, which is very low in preparation cost, friendly to the environment, simple in preparation method and low in equipment requirement;

[0021] 2. The Fenton-like catalyst of the application has a special spherical structure and a surface single electron signal, so that H2O2 can be rapidly activated and the organic pollutants can be quickly degraded under neutral room temperature conditions, the utilization rate of H2O2 is high, and the degradation effect is excellent;

[0022] 3. The Fenton-like catalyst of the present invention is a solid catalyst, which is easy to separate, recover and recycle. Furthermore, this Fenton-like catalyst has good stability and still has good degradation effect after multiple uses, and has good application prospects. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 Here is a SEM image of the Fenton-like catalyst from Example 1;

[0025] Figure 2 The EPR diagram of the Fenton-like catalyst in Example 1 is shown.

[0026] Figure 3 The degradation efficiency curves of RhB by the Fenton-like catalyst of Example 1 at different concentrations are shown.

[0027] Figure 4 The degradation efficiency curves of RhB by the Fenton-like catalyst of Example 1 at different pH values ​​are shown.

[0028] Figure 5 The curves show the degradation efficiency of RhB by the Fenton-like catalyst of Example 1 in the presence of different anions. Detailed Implementation

[0029] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] The preparation method of the Fenton-like catalyst in this embodiment includes the following steps:

[0034] S1: Calcination

[0035] The dried leaves were crushed and placed in a muffle furnace, heated to 700°C at a rate of 5°C / min, and calcined for 1 hour under a nitrogen atmosphere. The resulting powder was then ground to obtain the precursor.

[0036] S2: Impregnation

[0037] Weigh 2.06 g (10 mmol) of MoNa2O4 and 1.53 g (20 mmol) of CH4N2S, add 100 mL of deionized water to form a mixed solution; add 2 g of precursor to the mixed solution and impregnate for 2 h to obtain the impregnated mixed system.

[0038] S3: Hydrothermal reaction

[0039] The impregnated mixture was stirred in a water bath at 60°C for 20 min, and then placed in an oven at 180°C for 18 h to obtain the hydrothermal reaction product.

[0040] S4: Washing and drying

[0041] The hydrothermal reaction product was washed five times alternately with ethanol and deionized water. Finally, the washed product was dried in a 70°C oven to obtain a gray-black Fenton-like catalyst powder (denoted as MoS-L).

[0042] The SEM and EPR images of MoS-L are shown below. Figure 1 , Figure 2 ;from Figure 1 It can be seen that MoS-L has a spherical structure; from Figure 2 It can be seen that MoS-L has surface single-electron signals.

[0043] Example 2

[0044] The preparation method of the Fenton-like catalyst in this embodiment includes the following steps:

[0045] S1: Calcination

[0046] The dried leaves were crushed and placed in a muffle furnace, heated to 600°C at a rate of 8°C / min, and calcined for 2 hours under a nitrogen atmosphere. The resulting powder was then ground to obtain the precursor.

[0047] S2: Impregnation

[0048] Weigh 1.65 g (8 mmol) of MoNa2O4 and 1.22 g (16 mmol) of CH4N2S, add 100 mL of deionized water to form a mixed solution; add 2 g of precursor to the mixed solution and impregnate for 1.5 h to obtain the impregnated mixed system.

[0049] S3: Hydrothermal reaction

[0050] The impregnated mixture was stirred in a water bath at 50°C for 30 min, and then placed in an oven at 160°C for 24 h to obtain the hydrothermal reaction product.

[0051] S4: Washing and drying

[0052] The hydrothermal reaction product was washed three times alternately with ethanol and deionized water. Finally, the washed product was dried in a 60°C oven to obtain a gray-black Fenton-like catalyst powder.

[0053] Example 3

[0054] The preparation method of the Fenton-like catalyst in this embodiment includes the following steps:

[0055] S1: Calcination

[0056] The dried leaves were crushed and placed in a muffle furnace, heated to 650°C at a rate of 10°C / min, and calcined in a nitrogen atmosphere for 1.5 hours. The resulting powder was then ground to obtain the precursor.

[0057] S2: Impregnation

[0058] Weigh 2.47 g (12 mmol) of MoNa2O4 and 1.83 g (24 mmol) of CH4N2S, add 100 mL of deionized water to form a mixed solution; add 2 g of precursor to the mixed solution and impregnate for 1.5 h to obtain the impregnated mixed system.

[0059] S3: Hydrothermal reaction

[0060] The impregnated mixture was stirred in a water bath at 70°C for 20 min, and then placed in an oven at 200°C for 20 h to obtain the hydrothermal reaction product.

[0061] S4: Washing and drying

[0062] The hydrothermal reaction product was washed six times alternately with ethanol and deionized water. Finally, the washed product was dried in an 80°C oven to obtain a gray-black Fenton-like catalyst powder.

[0063] Experimental Example 1

[0064] Different weights of the Fenton-like catalyst prepared in Example 1 (0.01 g, 0.02 g, 0.03 g, 0.04 g, and 0.05 g) were weighed and added together with 10 μL of H2O2 to 50 mL of a pollutant solution with a concentration of 10 mg / L. The pH was maintained at its natural state (approximately 7.0), and the solution was continuously stirred at a constant temperature of 30 °C. Samples were taken at different time points to detect changes in pollutant concentration. The results are shown in [Figure number missing]. Figure 3 .

[0065] Depend on Figure 3 It is evident that the Fenton-like catalyst prepared by this invention exhibits excellent catalytic degradation effect on Rhodamine B. Compared with traditional Fenton catalysts, the Fenton-like catalyst of this invention possesses stronger reactivity and a faster degradation rate. This Fenton-like catalyst saves significant costs in both the synthesis and degradation processes, while also greatly reducing the time required to remove pollutants and inhibiting the continued environmental harm caused by pollutants.

[0066] Experimental Example 2

[0067] Weigh 0.01 g of the Fenton-like catalyst prepared in Example 1 and add it together with 10 μL of H2O2 into 50 mL of a 10 mg / L Rhodamine B solution. Adjust the pH of the solution with NaOH and HCl, or introduce different anions by adding NaCl, NaNO3, and Na2SO4 respectively. Stir continuously at a constant temperature of 30 °C, and take samples at different time points to detect the changes in pollutant concentration; the results are shown in […]. Figure 4 , Figure 5 .

[0068] Depend on Figure 4 , Figure 5 It can be seen that the Fenton-like catalyst prepared by the present invention can still maintain high degradation activity of Rhodamine B under different pH ranges (pH 3-11) and different anions, indicating that the Fenton-like catalyst prepared by the present invention has good adaptability to complex aquatic environments and can be applied to the treatment of actual polluted water bodies.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. The application of a Fenton-like catalyst in wastewater treatment, characterized in that, Wastewater containing organic pollutants was treated using a Fenton-like catalyst and H2O2. The pH value during the degradation treatment was 3-7, and the organic pollutant was Rhodamine B. The preparation method of the Fenton-like catalyst includes the following steps: S1: The dried leaves are crushed and then calcined to obtain the precursor; S2: The precursor is impregnated in a mixed solution of sodium molybdate and thiourea to obtain an impregnation mixture system; S3: After stirring the impregnation mixture, carry out a hydrothermal reaction to obtain the hydrothermal reaction product; S4: The hydrothermal reaction products are washed and dried to obtain a Fenton-like catalyst, which has a spherical structure. In step S1, the heating rate during calcination is 5-10 ℃ / min, the calcination temperature is 600-700 ℃, and the calcination time is 1-2 h. In step S2, the ratio of precursor, sodium molybdate, and thiourea is 1 g: 4-6 mmol: 8-12 mmol; the soaking time is 1.5-2.5 h. In step S3, the stirring temperature is 50-70 ℃ and the stirring time is 20-30 min; the hydrothermal reaction temperature is 160-200 ℃ and the hydrothermal reaction time is 18-24 h.

2. The application according to claim 1, characterized in that, In step S4, ethanol and deionized water are used alternately for washing; the number of washing cycles is 3-6, and the drying temperature is 60-80 ℃.

3. The application according to claim 1, characterized in that, The amount of Fenton-like catalyst used during degradation treatment is 0.2-1.0 g / L.

Images