A composite filter material for treating antimony-containing wastewater, its preparation method and application

Abstract

This application relates to the field of wastewater treatment technology, specifically disclosing a composite filter media for treating antimony-containing wastewater, its preparation method, and its application. The composite filter media for treating antimony-containing wastewater provided in this application is prepared from sludge, biochar, calcium hydroxide, and water in a weight ratio of 1:(0.1-0.6):(0.4-1.2):(0.5-2). The sludge is obtained from iron-containing acidic mining wastewater through alkali neutralization, sludge-water separation, and drying, with an iron content of 30-50 wt%. The biochar is prepared from biomass fermentation residue through high-temperature carbonization, and the biochar particle size is 1-4 mm. This application also provides a method for treating antimony-containing wastewater. The composite filter media for treating antimony-containing wastewater provided in this application can effectively adsorb antimony in antimony-containing wastewater, ensuring that the treated effluent meets wastewater discharge standards.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, specifically to a composite filter material for treating antimony-containing wastewater, its preparation method, and its application. Background Technology

[0002] Antimony-containing wastewater treatment has become a key focus in the environmental protection field in recent years. Due to the widespread use of antimony in industrial production, the discharge of antimony-containing wastewater has been increasing year by year, causing serious environmental pollution and threatening human health. Therefore, researching and developing efficient antimony-containing wastewater treatment technologies is particularly important. This will not only contribute to environmental protection but also reduce water waste, improve water quality, and promote sustainable development.

[0003] Existing technologies for treating antimony-containing wastewater mainly include chemical precipitation, adsorption, and ion exchange. Chemical precipitation, which uses chemical reagents to precipitate antimony, is simple to operate and highly efficient. However, it is primarily used for wastewater with high antimony content, and the cost of the chemical reagents used is relatively high, limiting its application. Adsorption utilizes various adsorbents to effectively remove antimony ions, but adsorbents are typically single-use and cannot be reused, leading to high operating costs. Ion exchange uses ion exchange resins to selectively exchange antimony ions, but ion exchange resins have a short working life, require frequent replacement, and are also expensive, thus limiting its widespread adoption. Summary of the Invention

[0004] In order to overcome the shortcomings of existing antimony-containing wastewater treatment technologies, such as high cost and inability to be widely used, this application provides a composite filter material for antimony-containing wastewater treatment, its preparation method and application.

[0005] In a first aspect, this application provides a composite filter material for treating antimony-containing wastewater, employing the following technical solution:

[0006] A composite filter media for treating antimony-containing wastewater is prepared using sludge, biochar, calcium hydroxide, and water in a weight ratio of 1:(0.1-0.6):(0.4-1.2):(0.5-2).

[0007] This application utilizes sludge, biochar, and calcium hydroxide to prepare a composite filter media with significant adsorption performance and stability. By mixing sludge, biochar, calcium hydroxide, and water in the aforementioned specific weight ratio, the resulting composite filter media possesses a good pore structure and a large specific surface area, effectively adsorbing antimony ions from wastewater, resulting in an antimony content in the treated effluent as low as below 0.3 mg / L. Specifically, sludge exhibits excellent specific adsorption treatment effect for antimony ions; biochar, as a precursor to activated carbon, possesses high adsorption capacity and chemical stability, not only improving the overall antimony adsorption efficiency of the composite filter media but also enhancing its mechanical strength and durability to a certain extent. In summary, the composite filter media provided in this application has advantages such as low raw material cost, good adsorption, and excellent stability. Its application in the treatment of antimony-containing wastewater can significantly reduce the antimony content in antimony-containing wastewater, enabling the antimony content in the effluent to meet national emission standards.

[0008] Optionally, the weight ratio of the sludge, biochar, calcium hydroxide and water is 1:(0.2-0.4):(0.6-1.0):(0.5-2).

[0009] In some embodiments, the weight ratio of the sludge, biochar, calcium hydroxide, and water can be 1:(0.1-0.2):0.8:1, 1:(0.1-0.3):0.8:1, 1:(0.1-0.4):0.8:1, 1:(0.1-0.6):0.8:1, 1:(0.2-0.3):0.8:1, (0.2-0.4):0.8:1, 1:(0.2-0.6):0.8:1, (0.3-0.4):0.8:1, (0.3-0.6):0.8:1, (0.4... -0.6): 0.8: 1, 1:0.3: (0.4-0.6): 1, 1:0.3: (0.4-0.8): 1, 1:0.3: (0.4-1.0): 1, 1:0.3: (0.4-1.2): 1, 1:0.3: (0.6-0.8): 1, 1:0.3: (0.6-1.0): 1, 1:0.3: (0.6-1.2): 1, 1:0.3: (0.8-1.0): 1, 1:0.3: (0.8-1.2): 1 or 1:0.3: (1.0-1.2): 1.

[0010] In one specific implementation, the weight ratio of the sludge, biochar, calcium hydroxide, and water can also be 1:0.1:0.8:1, 1:0.2:0.8:1, 1:0.3:0.8:1, 1:0.4:0.8:1, 1:0.6:0.8:1, 1:0.3:0.4:1, 1:0.3:0.6:1, 1:0.3:1.0:1, or 1:0.3:1.2:1.

[0011] Optionally, the sludge is obtained by neutralizing iron-containing acidic mine wastewater with alkali, separating the sludge from the water, and drying it, and the iron content in the sludge is 30-50 wt%.

[0012] In this application, high-iron sludge obtained from iron-containing acidic mine wastewater through alkali neutralization and sludge-water separation is used as one of the raw materials for composite filter media, which can significantly improve the treatment effect of composite filter media on antimony-containing wastewater. Specifically, the iron content in the high-iron sludge is controlled within the range of 30-50 wt%, which not only gives it good adsorption performance but also enhances the structural stability and mechanical strength of the composite filter media. In addition, the high-iron sludge also has a good heavy metal capture capacity, effectively removing antimony ions from wastewater during the treatment process, thereby achieving a good purification effect and ensuring that the effluent meets environmental discharge standards.

[0013] Optionally, the iron content in the sludge is 35-45 wt%.

[0014] In this application, through experimental investigation, it was found that by further controlling the iron content in the sludge within the above-mentioned range, the obtained composite filter material has more stable adsorption performance and higher antimony removal efficiency, which can reduce the antimony content in antimony-containing wastewater to below 0.2 mg / L.

[0015] In some embodiments, the iron content in the sludge may be 30-35 wt%, 30-40 wt%, 30-45 wt%, 30-50 wt%, 35-40 wt%, 35-45 wt%, 35-50 wt%, 40-45 wt%, 40-50 wt%, or 45-50 wt%.

[0016] In one specific implementation, the iron content in the sludge may also be 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%.

[0017] In some embodiments, the particle size of the composite filter material can be 3-6mm, 3-8mm, 3-10mm, 3-12mm, 6-8mm, 6-10mm, 6-12mm, 8-10mm, 8-12mm or 10-12mm.

[0018] In one specific implementation, the particle size of the composite filter material can also be 3mm, 6mm, 8mm, 10mm or 12mm.

[0019] Optionally, the biochar is prepared by high-temperature carbonization of biomass fermentation residue, and the particle size of the biochar is 1-4 mm.

[0020] Optionally, the biochar is prepared by heating the biomass fermentation residue to 300-700°C at a heating rate of 5-15°C, and carbonizing it at the above temperature for 1.5-3 hours to obtain biochar.

[0021] Optionally, the particle size of the composite filter material is 3-12 mm.

[0022] Secondly, this application provides a method for preparing composite filter media for treating antimony-containing wastewater.

[0023] A method for preparing a composite filter media for treating antimony-containing wastewater includes the following steps: mixing sludge, biochar, calcium hydroxide and water in a certain proportion, granulating and drying to obtain the composite filter media.

[0024] Thirdly, the application of the composite filter media for treating antimony-containing wastewater provided in this application in the treatment of antimony-containing wastewater.

[0025] A method for treating antimony-containing wastewater includes the following steps: passing the antimony-containing wastewater through a wastewater treatment tank pre-filled with the composite filter media for treating antimony-containing wastewater, maintaining the hydraulic retention time of the antimony-containing wastewater in the treatment tank for 6-12 hours, and effluent; wherein the pH of the antimony-containing wastewater is ≥4 and the antimony concentration is ≤10mg / L.

[0026] This application proposes a simple and low-cost treatment method for antimony-containing wastewater with specific properties of "pH≥4 and antimony concentration≤10mg / L". By adjusting the hydraulic retention time to the above range, this method can reduce the antimony concentration in the antimony-containing wastewater to below 0.3mg / L, making the effluent meet environmental discharge standards and showing great promise for application.

[0027] In some implementations, the hydraulic residence time can be 6-10 hours or 10-12 hours.

[0028] In one specific implementation, the hydraulic residence time can also be 6h, 10h or 12h.

[0029] In some embodiments, the antimony concentration in the antimony-containing wastewater may be 2.6-5.4 mg / L or 5.4-8.2 mg / L.

[0030] In one specific implementation, the antimony concentration in the antimony-containing wastewater may also be 2.6 mg / L, 5.4 mg / L, or 8.2 mg / L.

[0031] In summary, this application has the following beneficial effects:

[0032] 1. This application uses sludge, biochar, calcium hydroxide and water in a weight ratio of 1:(0.1-0.6):(0.4-1.2):(0.5-2) to prepare a composite filter material for treating antimony-containing wastewater. The composite filter material has a good pore structure and a large specific surface area, which can effectively adsorb antimony ions in wastewater, significantly reduce the antimony content in antimony-containing wastewater, and make the antimony content of the effluent as low as below 0.3 mg / L, thereby meeting the national emission standards.

[0033] 2. This application further controls the weight ratio of sludge, biochar, calcium hydroxide and water within the range of 1:(0.2-0.4):(0.6-1.0):(0.5-2), the iron content in the sludge within the range of 35-45wt%, and the particle size of the composite filter media within the range of 6-10mm, so that the antimony content in the obtained effluent can be as low as below 0.2mg / L.

[0034] 3. The antimony-containing wastewater treatment method provided in this application is applicable to the treatment of antimony-containing wastewater with pH ≥ 4 and antimony concentration ≤ 10 mg / L. By controlling the hydraulic retention time in the treatment method within the range of 6-12 hours, antimony ions in the wastewater can be significantly and effectively removed, thereby achieving a better purification effect and ensuring that the effluent meets environmental discharge standards. Detailed Implementation

[0035] In a first aspect, this application provides a composite filter material for treating antimony-containing wastewater, the preparation method of which includes the following steps: mixing sludge, biochar, calcium hydroxide, and water in a weight ratio of 1:(0.1-0.6):(0.4-1.2):(0.5-2), granulating, and drying to obtain a composite filter material with a particle size of 3-12 mm. Further, the weight ratio of the sludge, biochar, calcium hydroxide, and water is 1:(0.2-0.4):(0.6-1.0):(0.5-2).

[0036] The sludge is prepared by adding alkali to iron-containing acidic mine wastewater until the pH reaches 6-8 and the reaction is complete, followed by mud-water separation, and collecting the dewatered sludge for later use. The iron content in the sludge is 30-50 wt%. Further, the iron content in the sludge is 35-45 wt%.

[0037] The biochar preparation method is as follows: the temperature of biomass fermentation residue is increased to 300-700℃ at a heating rate of 5-15℃, and carbonized at the above temperature for 1.5-3 hours to obtain biochar with a particle size of 1-4mm.

[0038] Secondly, this application provides a method for treating antimony-containing wastewater, comprising the following steps: passing the antimony-containing wastewater through a wastewater treatment tank pre-placed with the composite filter media, maintaining the hydraulic retention time of the antimony-containing wastewater in the treatment tank for 6-12 hours, and effluent; wherein the pH of the antimony-containing wastewater is ≥4 and the antimony concentration is ≤10mg / L.

[0039] The raw materials, reagents, solvents, etc. used in this application are all commercially available.

[0040] The following detailed description of this application is provided in conjunction with preparation examples, embodiments, and performance testing experiments.

[0041] Preparation Examples 1-9

[0042] Preparation Examples 1-9 provide composite filter media for treating antimony-containing wastewater.

[0043] The difference in the above preparation examples is that the amount of each raw material added in the preparation of the composite filter material is shown in Table 1 below.

[0044] The preparation method of the composite filter media provided in Examples 1-9 includes the following steps: sludge with an iron content of 40%, biochar with a particle size of 2±1 mm, calcium hydroxide and water are mixed according to the weight ratio shown in Table 1, and then granulated and dried to obtain composite filter media with a particle size of 8 mm.

[0045] Table 1. Weight ratio of each raw material in the composite filter media provided in Examples 1-9

[0046]

[0047] Preparation Examples 10-13

[0048] Preparation Examples 10-13 provide composite filter media for treating antimony-containing wastewater.

[0049] The difference between the above preparation example and preparation example 3 is that the iron content of the sludge in the composite filter material is shown in Table 2 below.

[0050] Table 2. Iron content of sludge in the composite filter media provided in Preparation Examples 3 and 10-13

[0051]

[0052] Preparation Examples 14-17

[0053] Preparation Examples 14-17 provide composite filter media for treating antimony-containing wastewater.

[0054] The difference between the above preparation example and preparation example 3 is that the particle size of the composite filter material is as shown in Table 3 below.

[0055] Table 3. Particle size of the composite filter media provided in Preparation Examples 3 and 14-17

[0056]

[0057] Comparative Preparation Example 1

[0058] Comparative Preparation Example 1 provides a composite filter material for treating antimony-containing wastewater.

[0059] The difference between the above preparation example and preparation example 3 is that the weight ratio of sludge, biochar, calcium hydroxide and water is 1:1:0.2:1.

[0060] Comparative Preparation Example 2

[0061] Comparative preparation example 2 provides a composite filter material for treating antimony-containing wastewater.

[0062] The difference between the above preparation example and preparation example 3 is that the weight ratio of sludge, biochar, calcium hydroxide and water is 0.5:1:1:1.

[0063] Examples 1-17

[0064] Examples 1-17 provide a method for treating antimony-containing wastewater.

[0065] The difference between the above embodiments is that the composite filter media used in the antimony-containing wastewater treatment method are derived from preparation examples 1-17.

[0066] The antimony-containing wastewater treatment method provided in Examples 1-17 includes the following steps: antimony-containing wastewater with pH 4.7 and antimony concentration of 8.2 mg / L is passed through a wastewater treatment tank pre-filled with composite filter media, the hydraulic retention time of the antimony-containing wastewater in the treatment tank is maintained at 10 h, and the treated wastewater is obtained by effluent discharge. Example 18

[0067] Example 18 provides a method for treating antimony-containing wastewater.

[0068] The difference between the above embodiment and embodiment 3 is that the hydraulic retention time in the antimony-containing wastewater treatment method is 6 hours. Example 19

[0069] Example 19 provides a method for treating antimony-containing wastewater.

[0070] The difference between the above embodiment and embodiment 3 is that the hydraulic retention time in the antimony-containing wastewater treatment method is 12 hours. Example 20

[0071] Example 20 provides a method for treating antimony-containing wastewater.

[0072] The difference between the above embodiment and embodiment 3 is that the antimony-containing wastewater is replaced with antimony-containing wastewater with a pH of 5.3 and an antimony concentration of 2.6 mg / L. Example 21

[0073] Example 21 provides a method for treating antimony-containing wastewater.

[0074] The difference between the above embodiment and embodiment 3 is that the antimony-containing wastewater is replaced with antimony-containing wastewater with a pH of 6.3 and an antimony concentration of 5.4 mg / L.

[0075] Comparative Examples 1-2

[0076] Comparative Examples 1 and 2 each provide a method for treating antimony-containing wastewater.

[0077] The difference between the above comparative examples and Example 3 is that the composite filter media used in the antimony-containing wastewater treatment method are derived from comparative preparation examples 1-2. Comparative Example 3

[0078] Comparative Example 3 provides a method for treating antimony-containing wastewater.

[0079] The difference between the above comparative example and Example 3 is that the hydraulic retention time in the antimony-containing wastewater treatment method is 4 hours. Comparative Example 4

[0080] Comparative Example 4 provides a method for treating antimony-containing wastewater.

[0081] The difference between the above comparative example and Example 3 is that the antimony-containing wastewater was replaced with antimony-containing wastewater with a pH of 5.8 and an antimony concentration of 12.5 mg / L.

[0082] Performance testing

[0083] The antimony content in the treated wastewater obtained in Examples 1-21 and Comparative Examples 1-4 was detected, and the results are shown in Table 4 below.

[0084] The method for detecting antimony content is as follows: The antimony content in water is determined using atomic fluorescence spectrometry according to HJ 694—2014, "Determination of Mercury, Arsenic, Selenium, Bismuth and Antimony in Water". Note: The emission limit for 'tin' as a water pollutant from enterprises is 0.3 mg / L, as specified in GB30770-2014, "Emission Standard of Pollutants from Tin, Antimony and Mercury Industries".

[0085] Table 4 Antimony content in the treated wastewater obtained from Examples 1-21 and Comparative Examples 1-4

[0086]

[0087] Table 4 shows that after treating the antimony-containing wastewater using the methods provided in Examples 1-21, the antimony concentration in the effluent was 0.14-0.28 mg / L (<0.3 mg / L), which meets the water pollutant discharge standards. However, after treating the antimony-containing wastewater using the methods provided in Comparative Examples 1-4, the antimony concentration in the effluent was still as high as 0.66-1.64 mg / L (>0.3 mg / L), which does not meet the water pollutant discharge standards. Therefore, this application demonstrates that the composite filter media prepared using sludge, biochar, calcium hydroxide, and water, with the weight ratio of the four components controlled within the range of 1:(0.1-0.6):(0.4-1.2):(0.5-2), has a good treatment effect on antimony-containing wastewater with an antimony concentration ≤10 mg / L, reducing the antimony concentration in the wastewater to below 0.3 mg / L, thus ensuring that the antimony content in the effluent meets the national discharge standards.

[0088] The test results of Examples 1-9 show that after treating antimony-containing wastewater using the methods of Examples 1, 5-6, and 9, the antimony concentration in the effluent is 0.21-0.26 mg / L; while after treating antimony-containing wastewater using the methods of Examples 2-4 and 7-8, the antimony concentration in the effluent is 0.15-0.19 mg / L (<0.2 mg / L). Therefore, this application demonstrates that by further controlling the weight ratio of sludge, biochar, calcium hydroxide, and water within the range of 1:(0.2-0.4):(0.6-1.0):(0.5-2), the resulting composite filter media exhibits better treatment performance for antimony-containing wastewater.

[0089] The test results of Examples 3 and 10-13 show that as the iron content in the sludge of the composite filter media increases, the antimony concentration in the effluent after treating antimony-containing wastewater shows a trend of first decreasing and then increasing. Further comparison shows that when the iron content in the sludge is controlled within the range of 35-45 wt% in Examples 3 and 11-12, the obtained composite filter media has more stable adsorption performance and higher antimony removal efficiency, which can reduce the antimony content in antimony-containing wastewater to below 0.2 mg / L.

[0090] The test results of Examples 3 and 14-17 show that as the particle size of the composite filter media increases, the antimony concentration in the effluent after treating antimony-containing wastewater shows a trend of first decreasing and then increasing. Further comparison reveals that Examples 3 and 15-16, by controlling the particle size of the composite filter media within the range of 6-10 mm, obtained composite filter media with more stable adsorption performance and higher antimony removal efficiency, which can reduce the antimony content in antimony-containing wastewater to below 0.2 mg / L.

[0091] The test results of Examples 3, 18-19, and Comparative Example 3 show that after treating the antimony-containing wastewater using the methods of Examples 3 and 18-19, the antimony concentration in the effluent is 0.14-0.25 mg / L; while after treating the antimony-containing wastewater using the method of Comparative Example 3, the antimony concentration in the effluent is 1.17 mg / L. This indicates that by controlling the hydraulic retention time within the range of 6-12 hours in the treatment method for antimony-containing wastewater of this application, the antimony concentration in the antimony-containing wastewater can be reduced to below 0.3 mg / L.

[0092] The test results of Examples 3, 20-21, and Comparative Example 4 show that in Examples 3 and 20-21, when the antimony content of the antimony-containing wastewater is ≤10 mg / L, the antimony concentration in the treated effluent is less than 0.3 mg / L. However, when the antimony content of the antimony-containing wastewater is greater than 10 mg / L (the antimony content in Comparative Example 4 is as high as 12.5 mg / L), the antimony concentration in the treated effluent is 1.64 mg / L (>0.3 mg / L), which does not meet the water pollutant discharge standards. Therefore, it is demonstrated that the antimony-containing wastewater treatment method provided in this application is suitable for treating antimony-containing wastewater with a specific property of "antimony concentration ≤10 mg / L," and has a good treatment effect on the aforementioned antimony-containing wastewater.

[0093] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A composite filter media for treating antimony-containing wastewater, characterized in that, It is prepared using sludge, biochar, calcium hydroxide and water in a weight ratio of 1:(0.1-0.6):(0.4-1.2):(0.5-2); The sludge is obtained from iron-containing acidic mine wastewater through alkali neutralization, sludge-water separation, and drying. The iron content of the sludge is 30-50 wt%. The preparation method of the composite filter material includes the following steps: mixing sludge, biochar, calcium hydroxide and water in a certain proportion, granulating and drying to obtain the composite filter material.

2. The composite filter media for treating antimony-containing wastewater according to claim 1, characterized in that, The weight ratio of the sludge, biochar, calcium hydroxide and water is 1:(0.2-0.4):(0.6-1.0):(0.5-2).

3. The composite filter media for treating antimony-containing wastewater according to claim 1, characterized in that, The iron content in the sludge is 35-45 wt%.

4. The composite filter material for treating antimony-containing wastewater according to claim 1, characterized in that, The biochar is prepared by high-temperature carbonization of biomass fermentation residue, and the particle size of the biochar is 1-4 mm.

5. The composite filter media for treating antimony-containing wastewater according to claim 4, characterized in that, The biochar preparation method is as follows: the biomass fermentation residue is heated to 300-700℃ at a heating rate of 5-15℃, and carbonized at the above temperature for 1.5-3 hours to obtain biochar.

6. The composite filter media for treating antimony-containing wastewater according to any one of claims 1-5, characterized in that, The particle size of the composite filter material is 3-12 mm.

7. The method for preparing composite filter media for treating antimony-containing wastewater as described in any one of claims 1-6, characterized in that, Includes the following steps: Sludge, biochar, calcium hydroxide and water are mixed in a certain proportion, granulated and dried to obtain composite filter media.

8. The application of the composite filter media for treating antimony-containing wastewater as described in any one of claims 1-6 in the treatment of antimony-containing wastewater.

9. A method for treating antimony-containing wastewater, characterized in that, Includes the following steps: The antimony-containing wastewater is flowed through a wastewater treatment tank pre-placed with the composite filter media for treating antimony-containing wastewater as described in any one of claims 1-6, and the hydraulic retention time of the antimony-containing wastewater in the treatment tank is maintained at 6-12 hours, and the effluent is discharged. The antimony-containing wastewater has a pH ≥ 4 and an antimony concentration ≤ 10 mg / L.

Images