WO2024077831A1

WO2024077831A1 - Fenton sludge-based method for preparing two-stage adsorption material, and use

Info

Publication number: WO2024077831A1
Application number: PCT/CN2023/077180
Authority: WO
Inventors: 邓斌; 仇雅丽; 刘勇奇; 李成刚; 巩勤学; 李长东
Original assignee: 广东邦普循环科技有限公司; 湖南邦普循环科技有限公司
Priority date: 2022-10-13
Filing date: 2023-02-20
Publication date: 2024-04-18
Also published as: FR3140878A1; CN115770544A

Abstract

A fenton sludge-based method for preparing a two-stage adsorption material. The method comprises: performing primary pyrolysis on fenton sludge powder to obtain a first-stage adsorption material; and after the first-stage adsorption material adsorbs magnesium ions, performing secondary pyrolysis to obtain a second-stage adsorption material, wherein the temperature of the primary pyrolysis is 600-900℃, the first-stage adsorption material has good adsorption activity on magnesium metal, and the second-stage adsorption material has good adsorption activity on phosphorus, thereby achieving highly-efficient comprehensive treatment of fenton sludge, magnesium-containing wastewater and phosphorus-containing wastewater.

Description

A method for preparing two-stage adsorption material based on Fenton sludge and its application

Technical Field

The present application belongs to the technical field of solid waste treatment, and in particular relates to a method and application of preparing a two-stage adsorption material based on Fenton sludge.

Background technique

The Fenton process is an efficient sewage treatment technology. It is often used in the deep treatment of sewage due to its strong oxidizing properties, short reaction time, and high degradation efficiency. However, in the actual application of the Fenton process, its narrow _pH application range, low _H2O2 utilization rate, large amount of sludge generated during the reaction, and the Fenton sludge rich in iron and some difficult-to-degrade organic matter are hazardous solid wastes that cannot be properly disposed of. This has limited its large-scale application to a certain extent.

At present, the main methods for disposing Fenton sludge are incineration, landfill and solidification treatment. These treatment methods have great limitations. On the one hand, Fenton sludge contains rich iron elements and has high recycling value; on the other hand, Fenton sludge is a hazardous solid waste. During the incineration, landfill and solidification treatment process, it will produce waste gas, waste residue and waste liquid, which is easy to cause secondary pollution and pose a great potential danger to the environment. Therefore, seeking an economical and efficient Fenton sludge resource treatment method has become a research focus in this field.

CN113786804A discloses a preparation method and application of a magnetic porous composite material for adsorbing heavy metals, wherein the method comprises drying, grinding and screening Fenton sludge and fly ash, adding urea, potassium carbonate and water for ultrasonic dispersion, and then transferring to a magnetic stirrer for stirring, grinding and transferring the sample to a quartz boat after natural drying, and then placing it in a tube furnace for roasting, cooling it naturally to room temperature, washing it by centrifugation with water for multiple times until it is nearly neutral, and then washing it by centrifugation with ethanol, and drying it naturally. The magnetic porous composite material prepared by this method has good adsorption performance and adsorption capacity only for Cr(VI) in water, and its use is relatively single, and the resource utilization degree of Fenton sludge is not high.

CN114452936A discloses a preparation method and application of a magnetic adsorbent based on Fenton sludge, the preparation method comprising step S1, concentrating Fenton sludge, centrifugally dehydrating to obtain a dehydrated sample; step S2, drying the dehydrated sample to obtain a dry sample, wherein the iron content of the dry sample is 40% to 55%, the oxygen content is 25% to 35% and the carbon content is 10% to 25%; step S3, adding the ground sample, potassium permanganate, divalent copper salt and polyethylene glycol to water according to the mass ratio, stirring evenly and drying to constant weight to obtain a mixed sample; step S4, calcining the mixed sample at a target temperature to obtain a magnetic adsorbent. The preparation method has complex raw materials, and the magnetic adsorbent obtained can only adsorb antimony and thallium heavy metal ions, and the multi-stage utilization of the adsorbent cannot be achieved, and the resource utilization of Fenton sludge is still not high.

CN112108118A A magnetic biomass charcoal based on Fenton sludge and cellulose and its preparation method and application, the steps are as follows: (1) filtering Fenton sludge slurry, collecting the filter residue, and drying it at 100°C to 110°C for 40 to 50 hours to obtain a block solid; breaking the block solid and grinding it to a size greater than or equal to 200 mesh to obtain a solid powder, drying the powder at 100°C to 110°C for 10 to 15 hours to obtain Fenton sludge powder for later use; (2) taking the Fenton sludge powder in a dry small beaker, adding CMC and water, stirring for 1h to 3h, centrifuging, drying, grinding, transferring to a quartz boat, wrapping it with tin foil and placing it in a tube furnace, maintaining it at 300 to 700°C for (0.2 to 2.5)h in a nitrogen atmosphere, naturally cooling it to room temperature, taking it out, washing it with hot water until it is neutral, and drying it to constant weight. The adsorbent prepared by this method still only has a good adsorption effect on heavy metal Pb (II), and cannot effectively adsorb other pollutants such as phosphorus pollution in water bodies.

The adsorbents obtained by resource utilization of Fenton sludge in the above literature can only effectively adsorb heavy metal ions, but cannot take into account other pollutants in the water body, and cannot achieve multi-stage utilization of the adsorbent. The resource utilization of Fenton sludge is not high. Therefore, it is urgent to develop a resource utilization method of Fenton sludge.

Summary of the invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

In view of the shortcomings of the prior art, the purpose of the present application is to provide a method and application for preparing a two-stage adsorption material based on Fenton sludge, and the two-stage adsorption material can be obtained using only Fenton sludge as raw material.

To achieve this goal, this application adopts the following technical solutions:

In a first aspect, the present application provides a method for preparing a two-stage adsorption material based on Fenton sludge, the method comprising:

The Fenton sludge powder is subjected to a primary pyrolysis to obtain a primary adsorption material, and after the primary adsorption material adsorbs magnesium ions, a secondary pyrolysis is performed to obtain a secondary adsorption material.

In the present application, Fenton sludge powder is subjected to a primary pyrolysis to obtain a primary adsorption material, i.e., an iron-rich adsorbent, which has an excellent adsorption effect on magnesium ions in water bodies, and can thus be used to treat magnesium-containing wastewater; and the primary adsorption material adsorbed with magnesium is subjected to a secondary pyrolysis to obtain a secondary adsorption material with an excellent adsorption effect on phosphorus, i.e., a magnesium-rich adsorbent, because the introduction of magnesium-containing active functional groups can significantly improve the adsorption capacity for phosphorus, and thus can be further used to treat phosphorus-containing wastewater; thus, the present application uses Fenton sludge as a raw material, and a two-stage adsorbent can be prepared by two-step pyrolysis combined with magnesium adsorption, thereby achieving the technical effect of two-stage adsorption.

The method for preparing a two-stage adsorption material based on Fenton sludge provided in the present application can obtain a two-stage adsorption material using only Fenton sludge as a raw material, wherein the first-stage adsorption material has good adsorption activity for metallic magnesium, and the second-stage adsorption material has good adsorption activity for phosphorus, thereby achieving a two-stage adsorption effect for preparing the adsorption material using Fenton sludge, improving the resource utilization of Fenton sludge, and solving the problem that the adsorbent prepared from Fenton sludge in the prior art can only effectively adsorb heavy metal ions, cannot take into account other pollutants in the water body, and cannot achieve multi-stage utilization of the adsorbent, thereby achieving the technical effect of efficient and comprehensive treatment of Fenton sludge, magnesium-containing wastewater and phosphorus-containing wastewater.

As a preferred technical solution of the present application, the preparation process of the Fenton sludge powder includes: sequentially filtering, drying, grinding and sieving the Fenton sludge to obtain the Fenton sludge powder.

Optionally, the preparation process of the primary adsorption material includes: after the Fenton sludge powder is subjected to the primary pyrolysis, grinding and sieving in sequence to obtain a primary pyrolysis product, and washing, separating and drying the primary pyrolysis product in sequence to obtain the primary adsorption material.

This application uses Fenton sludge produced by the Fenton process as raw material, and can obtain a primary adsorption material (iron-rich adsorbent) through filter pressing dehydration, drying, grinding, screening and pyrolysis. It has low cost and excellent performance, simplifies the preparation process, and is easy to promote.

In the present application, the Fenton sludge powder is placed in a tubular furnace for a primary pyrolysis; in addition, while obtaining the primary adsorption material, the present application also enriches other heavy metals with lower content, thus saving the disposal costs of stabilization treatment and landfill.

As a preferred technical solution of the present application, the heating rate of the primary pyrolysis is 8 to 12°C/min, for example, it can be 8°C/min, 8.5°C/min, 9°C/min, 9.5°C/min, 10°C/min, 10.5°C/min, 11°C/min, 11.5°C/min or 12°C/min, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable; preferably it is 10°C/min.

Optionally, the temperature of the primary pyrolysis is 600-900°C, for example, it can be 600°C, 620°C, 650°C, 680°C, 700°C, 730°C, 750°C, 780°C, 800°C, 820°C, 850°C, 870°C or 900°C, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

The present application limits the temperature of the primary pyrolysis to 600-900°C. When the temperature is lower than 600°C, the magnetization effect of the Fenton sludge will be weak, and some organic matter may remain. This is because the temperature is low, and the dehydrogenation effect of FeOOH and Fe(OH) ₃ in the Fenton sludge is poor, and they cannot be converted into Fe ₃ O ₄ in large quantities, thereby affecting the magnetic separation effect; when the temperature is higher than 900°C, the magnetism of the Fenton sludge will be weakened. This is because under high temperature conditions, the formed Fe ₃ O ₄ is further deoxidized and converted into non-magnetic Fe ₂ O ₃ or FeO, thereby reducing the magnetism of the Fenton sludge, which is not conducive to magnetic separation.

Optionally, the primary pyrolysis time is 2 to 3 h, for example, 2 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h or 3 h, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

Optionally, the primary pyrolysis is carried out under a protective gas atmosphere.

Optionally, the protective gas includes nitrogen or argon.

As a preferred technical solution of the present application, the cleaning agent used for cleaning includes deionized water.

Optionally, a cleaning liquid is generated during the cleaning process, and the endpoint of the cleaning is that the pH of the cleaning liquid is 6 to 7.5, for example, it can be 6, 6.2, 6.4, 6.6, 6.8, 7, 7.2, 7.4 or 7.5, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

In the present application, the primary pyrolysis product is cleaned until the pH of the cleaning liquid is 6 to 7.5, and the surface and interior of the obtained primary adsorption material are also close to neutral, thereby avoiding the influence of pH on the adsorption process of magnesium ions by the primary adsorption material; wherein, if the pH is too high, the alkaline environment will cause the magnesium ions to precipitate, rather than being adsorbed on the surface of the primary adsorption material in an adsorbed state; if the pH is too low, the acidic environment will cause the magnesium ions to be unable to be effectively adsorbed by the primary adsorption material.

Optionally, the separation includes magnetic separation. The primary adsorption material prepared in the present application is an iron-rich adsorbent, which has high magnetism, that is, the primary pyrolysis product also has high magnetism, and can be separated efficiently and quickly by magnetic separation.

Optionally, the drying temperature is 60-80°C, for example, 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C, but is not limited to the listed values, and other values not listed in the numerical range are also applicable. In the present application, the drying can be carried out in an oven.

Optionally, the mesh size of the primary adsorption material is 100-150 mesh, for example, it can be 100 mesh, 105 mesh, 110 mesh, 115 mesh, 120 mesh, 125 mesh, 130 mesh, 135 mesh, 140 mesh, 145 mesh or 150 mesh, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

As a preferred technical solution of the present application, the primary adsorption material is mixed with a magnesium-containing solution, and a process of the primary adsorption material adsorbing magnesium ions is carried out.

In the present application, before mixing the primary adsorbent material with the magnesium-containing solution, the pH of the magnesium-containing solution is adjusted to 6-7 using 10wt% dilute hydrochloric acid and/or 5wt% sodium hydroxide solution, so as to further avoid the influence of the pH of the magnesium-containing solution being too high or too low on the adsorption process of magnesium ions by the primary adsorbent material. In addition, the magnesium-containing solution in the present application includes magnesium-containing wastewater.

Optionally, the concentration of magnesium ions in the magnesium-containing solution is 100-150 mg/L, for example, 100 mg/L, 105 mg/L, 110 mg/L, 115 mg/L, 120 mg/L, 125 mg/L, 130 mg/L, 135 mg/L, 140 mg/L, 145 mg/L or 150 mg/L, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

Optionally, the solid-liquid ratio of the primary adsorption material and the magnesium-containing solution is (0.5g-1.0g):(50mL-100mL), for example, it can be 0.5g:50mL, 0.5g:60mL, 0.5g:70mL, 0.5g:80mL, 0.5g:90mL, 0.5g:100mL, 0.8g:50mL, 0.8g:60mL, 0.8g:70mL, 0.8g:80mL, 0.8g:90mL, 0.8g:100mL, 1g:50mL, 1g:60mL, 1g:70mL, 1g:80mL, 1g:90mL or 1g:100mL, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

The present application defines the concentration of the magnesium-containing solution as 100-150 mg/L, and the material-liquid ratio of the primary adsorbent material and the magnesium-containing solution as (0.5 g-1.0 g): (50 mL-100 mL). This is because under the above conditions, the primary adsorbent material can reach magnesium adsorption saturation, which is beneficial to improving the phosphorus adsorption performance of the secondary adsorbent material. If the material-liquid ratio of the primary adsorbent material and the magnesium-containing solution is too high, the amount of magnesium-containing active functional groups in the secondary adsorbent material is too small, resulting in reduced phosphorus adsorption performance; if the material-liquid ratio of the primary adsorbent material and the magnesium-containing solution is too low, since the primary adsorbent material reaches saturation for magnesium adsorption, even if the magnesium ion content is increased, its adsorption amount will not increase, therefore, the performance of the secondary adsorbent material will not be significantly improved.

Optionally, the primary adsorption material and the magnesium-containing solution are mixed at a temperature of 15 to 35°C, for example, 15°C, 18°C, 20°C, 23°C, 25°C, 28°C, 30°C, 32°C or 35°C, but are not limited to the listed values, and other unlisted values within the numerical range are also applicable.

Optionally, the primary adsorption material and the magnesium-containing solution are mixed under shaking conditions.

Optionally, the oscillation time is 12 to 24 hours, for example, it can be 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

As a preferred technical solution of the present application, after the primary adsorption material adsorbs the magnesium ions, it is sequentially subjected to separation treatment and drying treatment to obtain an intermediate material.

Optionally, the separation process includes magnetic separation.

Optionally, the drying temperature is 50-80°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C or 85°C, but is not limited to the listed values, and other unlisted values within the range are also applicable.

As a preferred technical solution of the present application, the temperature of the secondary pyrolysis is 600-900°C, for example, it can be 600°C, 620°C, 650°C, 680°C, 700°C, 730°C, 750°C, 780°C, 800°C, 820°C, 850°C, 870°C or 900°C, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

The present application limits the temperature of secondary pyrolysis to 600-900°C. When the temperature is lower than 600°C, the carbonization degree of the material will decrease and the stability of the loaded magnesium will be poor. This is because the temperature is too low, the dehydrogenation effect of the secondary adsorption material is weakened, the proportion of hydrogen in the material is high, and the adsorption effect is weakened; when the temperature is higher than 900°C, the surface polarity and magnetism of the secondary adsorption material will be weakened. This is because the temperature is too high, the proportion of oxygen elements decreases, and the hydrophilicity of the material surface is reduced, which is not conducive to the adsorption of phosphorus by the secondary adsorption material.

Optionally, the secondary pyrolysis time is 2 to 3 hours, for example, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8h or 3h, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

Optionally, the heating rate of the secondary pyrolysis is 8 to 12°C/min, for example, it can be 8°C/min, 8.5°C/min, 9°C/min, 9.5°C/min, 10°C/min, 10.5°C/min, 11°C/min, 11.5°C/min or 12°C/min, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable; preferably it is 10°C/min.

Optionally, the secondary pyrolysis is carried out under a protective gas atmosphere.

Optionally, the protective gas includes nitrogen or argon.

Optionally, after the secondary pyrolysis, the intermediate material is ground and sieved in sequence to obtain the secondary adsorption material.

Optionally, the mesh size of the secondary adsorption material is 130-170 mesh, for example, it can be 130 mesh, 135 mesh, 140 mesh, 145 mesh, 150 mesh, 155 mesh, 160 mesh, 165 mesh or 170 mesh, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

As a preferred technical solution of the present application, the method comprises:

S1: Fenton sludge is filtered, dried, ground and sieved in sequence to obtain Fenton sludge powder, the temperature is increased to 600-900° C. at a heating rate of 8-12° C./min in a protective gas atmosphere, the Fenton sludge powder is subjected to primary pyrolysis for 2-3 hours, and then ground and sieved in sequence to obtain a primary pyrolysis product;

S2: washing the primary pyrolysis product until the pH of the washing liquid generated during the washing process is 6 to 7.5, and drying at a temperature of 60 to 80° C. after separation to obtain a primary adsorption material of 100 to 150 mesh;

S3: At a temperature of 15 to 35° C., the primary adsorbent material and a magnesium solution having a concentration of 100 to 150 mg/L are mixed by oscillation at a material-liquid ratio of (0.5 g to 1.0 g): (50 mL to 100 mL) for 12 to 24 hours, and then separated and treated. Drying at 50-80° C. to obtain an intermediate material;

S4: In a protective atmosphere, the temperature is raised to 600-900° C. at a heating rate of 8-12° C./min, and the intermediate material is subjected to secondary pyrolysis for 2-3 h, followed by grinding and sieving to obtain a secondary adsorption material of 130-170 mesh.

In the process of preparing two-stage adsorption materials by resource utilization of Fenton sludge, the present application does not use strong acids, strong bases, toxic and volatile solvents, and does not produce excrement harmful to the environment, which can meet the requirements of green environmental protection and high atomic utilization. In addition, the method for preparing two-stage adsorption materials based on Fenton sludge provided in the present application uses conventional and easily available equipment and reagents, does not require expensive equipment investment, has low cost, obvious treatment effect, and is easy to promote.

In a second aspect, the present application provides a primary adsorption material prepared by the method described in the first aspect, wherein the primary adsorption material is used for adsorbing magnesium.

In a third aspect, the present application provides a secondary adsorption material prepared by the method described in the first aspect, wherein the secondary adsorption material is used to adsorb phosphorus.

Compared with the prior art, the beneficial effects of this application are:

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are used to provide further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

FIG1 is a process flow chart of the method for preparing a two-stage adsorption material based on Fenton sludge provided in Examples 1-3 of the present application.

FIG. 2 is a SEM image of the primary adsorption material provided in Example 1 of the present application.

FIG3 is a SEM image of the secondary adsorption material provided in Example 1 of the present application.

FIG4 is a comparison chart of the phosphorus adsorption effects of the primary adsorption material and the secondary adsorption material provided in Example 1 of the present application.

Detailed ways

The technical solution of the present application is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only to help understand the present application and should not be regarded as specific limitations of the present application.

Example 1

This embodiment provides a method for preparing a two-stage adsorption material based on Fenton sludge, as shown in FIG1 , the method comprising:

S1: Fenton sludge is filtered, dried, ground and sieved in sequence to obtain Fenton sludge powder. In a nitrogen atmosphere, the temperature is increased to 800°C at a heating rate of 10°C/min, the Fenton sludge powder is subjected to primary pyrolysis for 2.5 hours, and then ground and sieved in sequence to obtain a primary pyrolysis product;

S2: The primary pyrolysis product is washed with deionized water until the pH of the washing liquid generated during the washing process is 7, and after magnetic separation, it is dried at a temperature of 70° C. to obtain a primary adsorption material of 130 mesh, as shown in FIG2 ;

S3: At a temperature of 25°C, the primary adsorbent material and a magnesium solution with a concentration of 130 mg/L were oscillated and mixed at a solid-liquid ratio of 0.8 g:80 mL for 18 hours, and then dried at 60°C after magnetic separation to obtain Intermediate materials;

S4: In a nitrogen atmosphere, the temperature was raised to 800°C at a heating rate of 10°C/min, and the intermediate material was subjected to secondary pyrolysis for 2.5 h, followed by grinding and sieving to obtain a secondary adsorption material of 150 mesh, as shown in FIG3 .

Example 2

S1: Fenton sludge is filtered, dried, ground and sieved in sequence to obtain Fenton sludge powder. In a nitrogen atmosphere, the temperature is increased to 600°C at a heating rate of 8°C/min, the Fenton sludge powder is pyrolyzed for 3 hours, and then ground and sieved in sequence to obtain a primary pyrolysis product;

S2: washing the primary pyrolysis product with deionized water until the pH of the washing liquid generated during the washing process is 7.5, and drying at 80° C. after magnetic separation to obtain a primary adsorption material of 100 mesh;

S3: at a temperature of 35° C., the primary adsorption material and a magnesium-containing solution with a concentration of 100 mg/L were oscillated and mixed at a solid-liquid ratio of 0.5 g:100 mL for 24 hours, and after magnetic separation, the intermediate material was dried at 80° C. to obtain the intermediate material;

S4: In a nitrogen atmosphere, the temperature was raised to 600°C at a heating rate of 8°C/min, and the intermediate material was subjected to secondary pyrolysis for 3 h, followed by grinding and sieving to obtain a secondary adsorption material of 130 mesh.

Example 3

S1: The Fenton sludge was filtered, dried, ground and sieved in sequence to obtain Fenton sludge powder. The temperature was raised to 900°C at a heating rate of 12°C/min in a nitrogen atmosphere. After 2 h of primary pyrolysis, the product was ground and sieved in sequence to obtain a primary pyrolysis product;

S2: washing the primary pyrolysis product with deionized water until the pH of the washing liquid generated during the washing process is 6, and drying at 60° C. after magnetic separation to obtain a primary adsorption material of 150 mesh;

S3: at a temperature of 15°C, the primary adsorption material and a magnesium solution with a concentration of 150 mg/L were oscillated and mixed at a solid-liquid ratio of 1.0 g:50 mL for 12 hours, and after magnetic separation, the intermediate material was dried at 50°C to obtain the intermediate material;

S4: In a nitrogen atmosphere, the temperature was raised to 900°C at a heating rate of 12°C/min, and the intermediate material was subjected to secondary pyrolysis for 2 h, followed by grinding and sieving to obtain a secondary adsorption material of 170 mesh.

Example 4

The difference between this embodiment and embodiment 1 is that the temperature of the primary pyrolysis in step S1 is 550° C., and the other process parameters and operating conditions are the same as those in embodiment 1.

Example 5

The difference between this embodiment and embodiment 1 is that the temperature of the primary pyrolysis in step S1 is 950° C., and the other process parameters and operating conditions are the same as those in embodiment 1.

Example 6

The difference between this embodiment and embodiment 1 is that the material-liquid ratio of the primary adsorption material and the magnesium-containing solution in step S3 is 0.8 g:40 mL, and the other process parameters and operating conditions are the same as those in embodiment 1.

Example 7

The difference between this embodiment and embodiment 1 is that the temperature of the secondary pyrolysis in step S4 is 550° C., and the other process parameters and operating conditions are the same as those in embodiment 1.

Example 8

The difference between this embodiment and embodiment 1 is that the temperature of the secondary pyrolysis in step S4 is 950° C., and the other process parameters and operating conditions are the same as those in embodiment 1.

Comparative Example 1

The difference between this comparative example and Example 1 is that in step S3, the primary adsorption material and the copper (Cu(II)) solution with a concentration of 130 mg/L are oscillated and mixed at a solid-liquid ratio of 0.8 g:80 mL, and the other process parameters and operating conditions are the same as those in Example 1.

The primary adsorption materials and secondary adsorption materials obtained in Examples 1-8 and Comparative Example 1 were tested for adsorption performance respectively, and the test conditions were as follows:

(1) Adsorption performance test of primary adsorption material: Take 200 mL of magnesium-containing wastewater with a concentration of about 100 mg/L, and use 10 wt% dilute hydrochloric acid and 5 wt% sodium hydroxide solution to adjust the pH of the magnesium-containing wastewater to 6-7; add a certain amount of primary adsorption material to the magnesium-containing wastewater, shake at room temperature for 24 hours, let it stand for sedimentation, and after solid-liquid separation, determine the concentration of magnesium ions in the filtrate, and calculate the removal rate of magnesium ions.

(2) Adsorption performance test of primary adsorbent material: Take 500 mL of phosphorus-containing wastewater with a concentration of about 100 mg/L, and use 10 wt% dilute hydrochloric acid and 5 wt% sodium hydroxide solution to adjust the pH of the phosphorus-containing wastewater to 6-8; add a certain amount of primary adsorbent material to the phosphorus-containing wastewater, oscillate at room temperature for 24 hours, let it stand for sedimentation, and after solid-liquid separation, measure the phosphorus concentration in the filtrate and calculate the phosphorus removal rate.

(3) Adsorption performance test of secondary adsorption material: Take 500 mL of phosphorus-containing wastewater with a concentration of about 100 mg/L, and use 10 wt% dilute hydrochloric acid and 5 wt% sodium hydroxide solution to adjust the pH of the phosphorus-containing wastewater to 6-8; add a certain amount of secondary adsorption material to the phosphorus-containing wastewater, oscillate at room temperature for 24 hours, let it stand for sedimentation, and after solid-liquid separation, measure the phosphorus concentration in the filtrate and calculate the phosphorus removal rate.

The magnesium adsorption performance of the primary adsorption material obtained in Example 1 was tested. The test results are shown in Table 1.

Table 1

The phosphorus adsorption performance of the secondary material obtained in Example 1 was tested, and the test results are shown in Table 2.

Table 2

The phosphorus adsorption performance of the primary adsorption material and the secondary adsorption material obtained in Example 1 was tested respectively, and the results are compared in Table 3.

table 3

The magnesium adsorption performance of the primary adsorption material obtained in Examples 2-5 was tested, and the results are shown in Table 4.

Table 4

The phosphorus adsorption performance of the secondary adsorption materials obtained in Examples 2-8 and Comparative Example 1 was tested. See Table 5.

table 5

From the data in Table 1, it can be seen that the primary adsorption material obtained after the primary pyrolysis of the Fenton sludge powder in the present application shows good adsorption activity for magnesium. From the data in Tables 2 and 3, as well as Figure 4, it can be seen that the present application performs a secondary pyrolysis on the primary adsorption material adsorbed with magnesium, and the secondary adsorption material obtained has an excellent adsorption effect on phosphorus. This illustrates that the method for preparing a two-stage adsorption material based on Fenton sludge provided in the present application can obtain a two-stage adsorption material using only Fenton sludge as a raw material, wherein the primary adsorption material has good adsorption activity for metallic magnesium, and the secondary adsorption material has good adsorption activity for phosphorus, achieving a two-stage adsorption effect of preparing adsorption materials with Fenton sludge, improving the resource utilization of Fenton sludge, and achieving the technical effect of efficient and comprehensive treatment of Fenton sludge, magnesium-containing wastewater and phosphorus-containing wastewater.

From the data in Table 4, it can be seen that the primary adsorption materials obtained in Example 2 and Example 3 also exhibit excellent adsorption activity for magnesium, which illustrates the preparation of the two-stage adsorption material based on Fenton sludge provided in this application. The primary adsorption materials prepared by the method have good adsorption activity for magnesium; while the adsorption activity of the primary adsorption materials obtained in Examples 4 and 5 for magnesium is slightly lower than that in Example 1. This is because the primary pyrolysis temperature in Example 4 is too low, and the primary pyrolysis temperature in Example 5 is too high, which shows that a suitable primary pyrolysis temperature range is more conducive to improving the adsorption efficiency of the primary adsorption material for magnesium.

From the data in Table 5, we can see that:

(1) The secondary adsorption materials obtained in Examples 2 and 3 also exhibit good adsorption activity for phosphorus, indicating that the secondary adsorption materials prepared by the method for preparing two-stage adsorption materials based on Fenton sludge provided in the present application all have good adsorption activity for phosphorus; and the adsorption activity of the secondary adsorption materials obtained in Examples 4 and 5 for phosphorus is not much different from that in Examples 1-3. This is because in the process of preparing the secondary adsorption materials in the present application, the adsorption amount of magnesium by the primary adsorption materials reaches saturation, that is, the magnesium content in the secondary materials of Examples 4 and 5 is similar to that in Examples 1-3. Therefore, the adsorption capacity of the secondary adsorption materials for phosphorus is similar.

(2) The phosphorus adsorption activity of the secondary adsorption materials obtained in Examples 6-8 is lower than that in Example 1. This is because the material-liquid ratio of the primary adsorption material and the magnesium-containing solution in Example 6 is too high, and the amount of magnesium-containing active functional groups in the secondary adsorption material is too small, resulting in reduced phosphorus adsorption performance; the temperature of the secondary pyrolysis in Example 7 is too low, the dehydrogenation effect of the secondary adsorption material is weakened, the proportion of hydrogen in the material is high, the adsorption effect is weakened, and the carbonization degree of the material is reduced, and the stability of the loaded magnesium is poor; the temperature of the secondary pyrolysis in Example 8 is too high, the proportion of oxygen decreases, and the hydrophilicity of the material surface is reduced, which is not conducive to the adsorption of phosphorus by the secondary adsorption material.

(3) The phosphorus adsorption activity of the secondary adsorbent material obtained in Comparative Example 1 is much lower than that in Example 1. This is because the primary adsorbent material in the comparative example adsorbs copper ions and then undergoes secondary pyrolysis to obtain the secondary adsorbent material, rather than adsorbing magnesium ions. This further confirms that the method for preparing a two-stage adsorbent material based on Fenton sludge provided in the present application can obtain a two-stage adsorbent material using only Fenton sludge as a raw material, wherein the primary adsorbent material has good adsorption activity for metallic magnesium, and the secondary adsorbent material has good adsorption activity for phosphorus, reaching The two-stage adsorption effect of preparing adsorption materials with Fenton sludge was achieved, the resource utilization of Fenton sludge was improved, and the technical effect of efficient comprehensive treatment of Fenton sludge, magnesium-containing wastewater and phosphorus-containing wastewater was achieved.

The applicant declares that the above is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Technical personnel in the relevant technical field should understand that any changes or substitutions that can be easily thought of by technical personnel in the relevant technical field within the technical scope disclosed in the present application are within the protection scope and disclosure scope of the present application.

Claims

A method for preparing a two-stage adsorption material based on Fenton sludge, wherein the method comprises:

The Fenton sludge powder is subjected to a primary pyrolysis to obtain a primary adsorption material, and after the primary adsorption material adsorbs magnesium ions, a secondary pyrolysis is performed to obtain a secondary adsorption material.
The method according to claim 1, wherein the preparation process of the Fenton sludge powder comprises: sequentially filtering, drying, grinding and sieving the Fenton sludge to obtain the Fenton sludge powder.
The method according to claim 1, wherein the preparation process of the primary adsorption material comprises:

After the primary pyrolysis, the Fenton sludge powder is ground and sieved in sequence to obtain a primary pyrolysis product, and the primary pyrolysis product is washed, separated and dried in sequence to obtain the primary adsorption material.
The method according to claim 1, 2 or 3, wherein the heating rate of the primary pyrolysis is 8 to 12°C/min;

Optionally, the primary pyrolysis temperature is 600-900°C;

Optionally, the primary pyrolysis time is 2 to 3 hours;

Optionally, the primary pyrolysis is carried out under a protective gas atmosphere;

Optionally, the protective gas includes nitrogen or argon.
The method according to claim 3, wherein the cleaning agent used in the cleaning comprises deionized water;

Optionally, a cleaning solution is generated during the cleaning process, and the end point of the cleaning is when the pH of the cleaning solution is 6 to 7.5;

Optionally, the separation comprises magnetic separation;

Optionally, the drying temperature is 60-80°C;

Optionally, the mesh size of the primary adsorption material is 100-150 meshes.
The method according to any one of claims 1 to 5, wherein the primary adsorption material is The first-level adsorption material is mixed with the first-level adsorption material to adsorb magnesium ions;

Optionally, the concentration of magnesium ions in the magnesium-containing solution is 100-150 mg/L;

Optionally, the material-liquid ratio of the primary adsorption material and the magnesium-containing solution is (0.5 g to 1.0 g): (50 mL to 100 mL);

Optionally, the primary adsorption material and the magnesium-containing solution are mixed at a temperature of 15 to 35° C.;

Optionally, the primary adsorption material and the magnesium-containing solution are mixed under oscillating conditions;

Optionally, the oscillation time is 12 to 24 hours.
The method according to any one of claims 1 to 6, wherein after the primary adsorption material adsorbs the magnesium ions, separation treatment and drying treatment are sequentially performed to obtain an intermediate material;

Optionally, the separation process includes magnetic separation;

Optionally, the drying temperature is 50-80°C.
The method according to any one of claims 1 to 7, wherein the temperature of the secondary pyrolysis is 600 to 900°C;

Optionally, the secondary pyrolysis time is 2 to 3 hours;

Optionally, the heating rate of the secondary pyrolysis is 8 to 12°C/min;

Optionally, the secondary pyrolysis is carried out under a protective gas atmosphere;

Optionally, the protective gas includes nitrogen or argon;

Optionally, after the intermediate material is subjected to the secondary pyrolysis, it is ground and sieved in sequence to obtain the secondary adsorption material;

Optionally, the mesh size of the secondary adsorption material is 130-170 meshes.
The method according to any one of claims 1 to 8, wherein the method comprises:

S1: Fenton sludge is filtered, dried, ground and sieved in sequence to obtain Fenton sludge powder. In a protective gas atmosphere, the temperature is raised to 600-900°C at a heating rate of 8-12°C/min. The Fenton sludge powder is subjected to primary pyrolysis for 2 to 3 hours, and then ground and sieved in sequence to obtain a primary pyrolysis product;

S2: washing the primary pyrolysis product until the pH of the washing liquid generated during the washing process is 6 to 7.5, and drying at a temperature of 60 to 80° C. after separation to obtain a primary adsorption material of 100 to 150 mesh;

S3: at a temperature of 15 to 35° C., the primary adsorption material and a magnesium-containing solution having a concentration of 100 to 150 mg/L are oscillated and mixed at a material-liquid ratio of (0.5 g to 1.0 g): (50 mL to 100 mL) for 12 to 24 hours, and after separation, the mixture is dried at 50 to 80° C. to obtain an intermediate material;

S4: In a protective atmosphere, the temperature is raised to 600-900° C. at a heating rate of 8-12° C./min, and the intermediate material is subjected to secondary pyrolysis for 2-3 h, followed by grinding and sieving to obtain a secondary adsorption material of 130-170 mesh.
Use of a primary adsorption material prepared by the method according to any one of claims 1 to 9, wherein the primary adsorption material is used for adsorbing magnesium.
A use of a secondary adsorption material prepared by the method according to any one of claims 1 to 9, wherein the secondary adsorption material is used for adsorbing phosphorus.