Preparation method of modified coal gangue ceramsite adsorbing material for treating phosphorus-containing water body

Abstract

The invention relates to the field of water treatment adsorption materials, in particular to a preparation method of a modified coal gangue ceramsite adsorption material for treating a phosphorus-containing water body, and aims to solve the problems that binding sites of pores and anions in existing coal gangue ceramsite are limited, a saturation state is easy to achieve, the adsorption capacity is limited, and the existing coal gangue ceramsite is easy to saturate and large in usage amount. According to the preparation method, coal gangue ceramsite is used as a main raw material for comprehensive utilization to prepare the modified coal gangue ceramsite adsorption material, comprehensive utilization of coal gangue solid waste is achieved, impurities on the coal gangue ceramsite can be effectively removed after acid activation, pore channels are cleaned and expanded, the adsorption performance of the coal gangue ceramsite is improved, and the coal gangue ceramsite adsorption material is suitable for industrial production. After the coal gangue ceramsite is modified by using the modification liquid, the loaded iron element, lanthanum element and phosphate radical ions are easily coordinated and combined, so that inorganic pollutants such as phosphate in a water body can be efficiently adsorbed and removed, adsorption sites are provided, the adsorption effect is promoted, and the adsorption performance is improved.

Description

Technical Field

[0001] The present invention relates to the field of water treatment adsorption materials, and specifically to a preparation method of a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies. Background Art

[0002] Phosphorus is considered the main limiting factor leading to water eutrophication, which can cause excessive algae growth and water quality deterioration. The threshold concentration triggering water eutrophication can be as low as 10 μg / L. Therefore, reducing the phosphorus content in water bodies is an important way to prevent and control water eutrophication. However, when natural water bodies are eutrophic, the phosphate content rarely exceeds 2 mg / L, far lower than the treatment conditions of chemical precipitation and flocculation methods for domestic sewage or industrial wastewater. These methods have poor treatment effects on such low-concentration phosphorus-containing water bodies. In addition, although the biological method can effectively remove low-concentration phosphorus-containing water bodies, it also has the disadvantages of large floor area and high cost.

[0003] The adsorption method has the characteristics of stable effluent water quality, strong selectivity, wide applicable range of sewage concentration, and simple operation, so it is often used for the removal and separation of extremely low-concentration substances in water. Due to the extremely high requirements of surface water standards for phosphorus concentration, the market has a major demand for technologies that can control phosphorus concentration at an ultra-low level. Common phosphorus-removing adsorbents are generally divided into two categories: natural adsorbents and synthetic adsorbents. Natural adsorbents such as fly ash, steel slag, zeolite, etc. have the disadvantages of poor adsorption efficiency and large dosing amounts, while synthetic adsorbents have relatively high costs.

[0004] Coal gangue is a solid waste associated with coal mining. If not properly disposed of, it will cause serious problems of land occupation and ecological environment damage. The comprehensive management and utilization of coal gangue in mining areas are imminent. Coal gangue ceramsite, which is processed from coal gangue, a by-product of coal mining, has the advantage of low cost. Moreover, like ordinary ceramsite, coal gangue ceramsite is a lightweight material with internal pores, uniform morphology and composition, low density, low price, corrosion resistance, low temperature resistance, and excellent insulation performance, and its internal pores are small honeycomb-shaped closed channels. It is an excellent material for making adsorption, thermal insulation, heat insulation, moisture-proof, noise reduction and other products, and is also an important way to achieve the purpose of treating waste with waste in the resource utilization of coal gangue solid waste.

[0005] However, like ordinary ceramsite, the internal pores of coal gangue ceramsite have limited binding sites with anions, are easily saturated, and have limited adsorption capacity. It has the disadvantage of being easily saturated and having a large usage amount. Therefore, it is of great significance to develop a preparation method of a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies.

[0006] In view of the above technical defects, a solution is now proposed. Summary of the Invention

[0007] In order to overcome the above technical problems, the purpose of the present invention is to provide a preparation method of a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies, which solves the problems that the pores inside the existing coal gangue ceramsite have limited binding sites with anions, are easily saturated, have limited adsorption capacity, and have the disadvantages of easy saturation and large usage amount.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] A preparation method of a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies includes the following steps:

[0010] Step 1, weighing raw materials; wherein, the raw materials include the following components in parts by weight:

[0011] 10 parts of coal gangue ceramsite, 1 - 20 parts of modifier, 0.1 - 20 parts of stabilizer, and 15 - 20 parts of deionized water;

[0012] Step 2, preparing a modification solution;

[0013] Step 3, pre-treating the coal gangue ceramsite;

[0014] Step 4, adding the pre-treated coal gangue ceramsite into the modification solution, and then using a high-speed constant-temperature shaker for constant-temperature shaking and mixing to obtain pre-modified coal gangue ceramsite;

[0015] Step 5, cleaning the pre-modified coal gangue ceramsite with a cleaning agent, and then roasting it in a muffle furnace to obtain a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies.

[0016] As a preferred embodiment of the present invention, the modifier in Step 1 includes 1 - 10 parts of ferric salt and 1 - 10 parts of lanthanum salt;

[0017] As a preferred embodiment of the present invention, the ferric salt includes one or more of compounds or hydrated compounds of ferric chloride, ferric sulfate, and ferric nitrate.

[0018] As a preferred embodiment of the present invention, the lanthanum salt includes one or more of compounds or hydrated compounds of lanthanum chloride and lanthanum nitrate.

[0019] As a preferred embodiment of the present invention, the stabilizer in Step 1 is one or more of sodium hydroxide solution, potassium hydroxide solution, calcium hydroxide solution, barium hydroxide solution, and ammonia water with a mass fraction of 10 - 30%.

[0020] As a preferred embodiment of the present invention, the preparation process of the modification solution in Step 2 is specifically as follows:

[0021] Add the modifier to deionized water, and stir it at a constant temperature for 10 min at a temperature of 40 °C and a stirring rate of 300 r / min to completely dissolve the modifier. Then adjust the pH to 10 - 11 with a stabilizer, and then perform ultrasonic treatment for 30 - 90 min at a temperature of 40 - 60 °C and an ultrasonic frequency of 30 kHz to obtain a modified solution.

[0022] As a preferred embodiment of the present invention, the pretreatment process of the coal gangue ceramsite in step three is specifically as follows:

[0023] Immerse the coal gangue ceramsite in an acidic solution to perform acidic activation on its surface, and after soaking for a certain time, wash it 3 times with a cleaning agent.

[0024] As a preferred embodiment of the present invention, the acidic solution is a 30% by mass HCl solution; the soaking time ≥ 24 h; the cleaning agent includes one or two of deionized water and ethanol.

[0025] As a preferred embodiment of the present invention, the process of constant temperature shaking and mixing in step four is specifically as follows:

[0026] Immerse the pretreated coal gangue ceramsite in the modifier at a solid-liquid ratio of 1:8 - 12, and then perform constant temperature shaking and mixing for 6 - 10 h at a shaking rate of 160 - 240 rpm and a temperature of 40 °C using a high-speed constant temperature shaker. Then let it stand for 14 - 18 h to obtain pre-modified coal gangue ceramsite.

[0027] As a preferred embodiment of the present invention, the process of cleaning the pre-modified coal gangue ceramsite in step five is specifically as follows:

[0028] First, wash it 3 times with absolute ethanol, then wash it 3 times with deionized water, and then dry it at a low temperature in an oven.

[0029] As a preferred embodiment of the present invention, the drying temperature in the low-temperature drying process ≤ 80 °C, and the drying time ≤ 6 h.

[0030] As a preferred embodiment of the present invention, the process of roasting in step five is specifically as follows:

[0031] Heat from room temperature to 400 °C, control the heating time to be 100 min, keep it at 400 °C for 3 - 4 h, and then take it out after cooling with the furnace.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] Preparation method of modified coal gangue ceramsite adsorption material for treating phosphorus-containing water body. First, prepare a modification solution, then pretreat the coal gangue ceramsite, and then add the pretreated coal gangue ceramsite into the modification solution. After that, use a high-speed constant-temperature shaker to perform constant-temperature shaking and mixing to obtain pre-modified coal gangue ceramsite. Then, use a cleaning agent to clean the pre-modified coal gangue ceramsite, and then calcine it in a muffle furnace to obtain a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water body. This preparation method uses coal gangue ceramsite as the main raw material to comprehensively utilize and prepare a modified coal gangue ceramsite adsorption material, realizing the comprehensive utilization of coal gangue solid waste, reducing environmental pollution and resource waste, and having good economic and social benefits. After acid activation with hydrochloric acid, impurities on the coal gangue ceramsite can be effectively removed, and the pores can be cleaned and expanded to improve its adsorption performance. After modification treatment of the coal gangue ceramsite with the modification solution, iron ions and lanthanum ions are introduced onto the coal gangue ceramsite, and metal oxides are formed after calcination, thereby adding a certain amount of metal oxides to the surface of the coal gangue ceramsite. The loaded iron element, lanthanum element and phosphate ions are easy to form coordination bonds, which can achieve efficient adsorption and removal of inorganic pollutants such as phosphates in water, provide adsorption sites, promote the adsorption effect, and improve the adsorption performance, so as to achieve the purpose of high adsorption, low cost, easy sedimentation, easy separation and recycling of the modified coal gangue ceramsite adsorption material. Brief Description of the Drawings

[0034] For the convenience of those skilled in the art to understand, the present invention will be further described below with reference to the accompanying drawings.

[0035] Figure 1 It is a process flow block diagram of the preparation method of the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water body of the present invention;

[0036] Figure 2 It is a physical diagram of the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water body prepared in Example 1 of the present invention;

[0037] Figure 3 It is an EDS spectrum of the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water body prepared in Example 1 of the present invention. Detailed Description of the Embodiments

[0038] In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] Example 1:

[0040] Please refer to Figure 1-2 As shown, the present embodiment is a preparation method of a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies, including the following steps:

[0041] Step 1: Weigh 2.75 g of FeCl 3 ·6H 2 O and 3.15 g of LaCl 3 ·7H 2 O and add them to 15 g of deionized water. Under the conditions of a temperature of 40°C and a stirring rate of 300 r / min, stir constantly for 10 min to completely dissolve the modifier. Then, adjust the pH to 10 with 20% ammonia water by mass fraction. After that, under the conditions of a temperature of 40°C and an ultrasonic frequency of 30 kHz, perform ultrasonic treatment for 30 min to obtain a modified solution;

[0042] Step 2: Immerse 10 g of coal gangue ceramsite in a 30% HCl solution by mass fraction to perform acid activation on its surface. After soaking for 24 h, wash it 3 times with deionized water to obtain pretreated coal gangue ceramsite;

[0043] Step 3: Immerse the pretreated coal gangue ceramsite in the modifier at a solid-liquid ratio of 1:8. Then, use a high-speed constant-temperature shaker to perform constant-temperature shaking and mixing for 6 h under the conditions of a shaking rate of 160 rpm and a temperature of 40°C. After that, let it stand for 18 h to obtain pre-modified coal gangue ceramsite.

[0044] Step 4: Wash the pre-modified coal gangue ceramsite 3 times with absolute ethanol first, then wash it 3 times with deionized water. After that, dry it in an oven at a drying temperature of 40°C for 6 h. Then, add it to a muffle furnace, control the heating time to be 100 min to heat the muffle furnace from room temperature to 400°C. After heating to 400°C, keep it for 3 h. Then, take it out after cooling with the furnace to obtain a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies.

[0045] Perform energy spectrum analysis on the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies in Example 1 to obtain an EDS spectrum, as Figure 3 shown. The specific elemental composition is shown in Table 1, the energy spectrum analysis result table:

[0046]

[0047] From Figure 3 and the test results in Table 1, it can be seen that the Fe and La elements are successfully introduced into the coal gangue ceramsite, thereby improving its adsorption effect.

[0048] Example 2:

[0049] Please refer to Figure 1As shown in the figure, this embodiment is a preparation method of a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies, including the following steps:

[0050] Step 1: Weigh 2.75 g of FeCl 3 ·6H 2 O and 6.34 g of LaCl 3 ·7H 2 O, add them to 15 g of deionized water, stir constantly at a constant temperature of 40 °C and a stirring rate of 300 r / min for 10 min to completely dissolve the modifier. Then, adjust the pH to 10 with 20% ammonia water by mass fraction. After that, perform ultrasonic treatment for 60 min at a temperature of 60 °C and an ultrasonic frequency of 30 kHz to obtain a modified solution;

[0051] Step 2: Immerse 10 g of coal gangue ceramsite in a 30% HCl solution by mass fraction to perform acid activation on its surface. After soaking for 24 h, wash it 3 times with deionized water to obtain pretreated coal gangue ceramsite;

[0052] Step 3: Immerse the pretreated coal gangue ceramsite in the modifier at a solid-liquid ratio of 1:8. Then, use a high-speed constant-temperature shaker to perform constant-temperature shaking and mixing for 8 h at a shaking rate of 200 rpm and a temperature of 40 °C. After that, let it stand for 16 h to obtain pre-modified coal gangue ceramsite.

[0053] Step 4: Wash the pre-modified coal gangue ceramsite 3 times with absolute ethanol first, then wash it 3 times with deionized water. After that, dry it in an oven at a drying temperature of 60 °C for 4 h. Then, add it to a muffle furnace, control the heating time to 100 min to heat the muffle furnace from room temperature to 400 °C. After heating to 400 °C, keep it for 3 h. Then, take it out after cooling with the furnace to obtain a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies.

[0054] Example 3:

[0055] Please refer to Figure 1 As shown in the figure, this embodiment is a preparation method of a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies, including the following steps:

[0056] Step 1: Weigh 5.5 g of FeCl 3 ·6H 2 O and 3.15 g of LaCl 3 ·7H 2O was added to 15 g of deionized water, and under the conditions of a temperature of 40 °C and a stirring rate of 300 r / min, it was stirred at a constant temperature for 10 min to completely dissolve the modifier. Then, the pH was adjusted to 10 with a 20% sodium hydroxide solution, and then ultrasonic treatment was carried out for 90 min under the conditions of a temperature of 40 °C and an ultrasonic frequency of 30 kHz to obtain a modified solution;

[0057] Step 2: 10 g of coal gangue ceramsite was soaked in a 30% HCl solution to acid-activate its surface. After soaking for 24 h, it was washed 3 times with deionized water to obtain pretreated coal gangue ceramsite;

[0058] Step 3: The pretreated coal gangue ceramsite was immersed in the modifier at a solid-liquid ratio of 1:8, and then a high-speed constant-temperature shaker was used to carry out constant-temperature shaking and mixing for 10 h under the conditions of a shaking rate of 240 rpm and a temperature of 40 °C. Then, it was left standing for 14 h to obtain pre-modified coal gangue ceramsite.

[0059] Step 4: The pre-modified coal gangue ceramsite was first washed 3 times with absolute ethanol, then washed 3 times with deionized water, and then dried in an oven at a drying temperature of 80 °C for 2 h. Then, it was added to a muffle furnace, and the muffle furnace was heated from room temperature to 400 °C in 100 min. After heating to 400 °C, it was maintained for 3 h, and then taken out after cooling with the furnace to obtain a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies.

[0060] Control Example 1:

[0061] This control example is a preparation method of a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies, including the following steps:

[0062] Step 1: Weigh 8 g of nano-Fe 3 O 4 was added to 15 g of deionized water, and under the conditions of a temperature of 40 °C and a stirring rate of 300 r / min, it was stirred at a constant temperature for 10 min. Then, the pH was adjusted to 10 with a 20% sodium hydroxide solution, and then ultrasonic treatment was carried out for 90 min under the conditions of a temperature of 40 °C and an ultrasonic frequency of 30 kHz to obtain a modified solution;

[0063] Step 2: 10 g of coal gangue ceramsite was soaked in a 30% HCl solution to acid-activate its surface. After soaking for 24 h, it was washed 3 times with deionized water to obtain pretreated coal gangue ceramsite;

[0064] Step 3: Immerse the pretreated coal gangue ceramsite in the modifier at a solid-liquid ratio of 1:8, and then use a high-speed constant-temperature shaker to perform constant-temperature shaking and mixing for 10 h under the conditions of a shaking rate of 240 rpm and a temperature of 40 °C. After that, let it stand for 14 h to obtain the pre-modified coal gangue ceramsite.

[0065] Step 4: Wash the pre-modified coal gangue ceramsite 3 times with absolute ethanol first, then wash it 3 times with deionized water, and then dry it in an oven at a drying temperature of 80 °C for 2 h. After that, add it to a muffle furnace, control the heating time to 100 min to heat the muffle furnace from room temperature to 400 °C, keep it at 400 °C for 3 h, and then take it out after cooling with the furnace to obtain the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies.

[0066] Blank Example 1:

[0067] This blank example is a preparation method of a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies, including the following steps:

[0068] Soak 10 g of coal gangue ceramsite in a 30% (mass fraction) HCl solution to perform acid activation on its surface. After soaking for 24 h, wash it 3 times with deionized water, and then dry it in an oven at a drying temperature of 65 °C for 2 h to obtain the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies.

[0069] Perform phosphate adsorption tests on the modified coal gangue ceramsite adsorption materials for treating phosphorus-containing water bodies in Examples 1-3, Control Example 1, and Blank Example 1;

[0070] The test conditions are as follows: The simulated phosphate solution is prepared with potassium dihydrogen phosphate (2 mg / L), and the phosphate concentration is the concentration of lakes (reservoirs) in Class V water (GB 3838-2002). The dosage of the test sample is 1 g / L, the pH is adjusted to 8, and then use a high-speed constant-temperature shaker to shake for 6 h under the condition of a shaking rate of 220 r / min. After that, test the phosphate concentration. The adsorption test results are shown in Table 1, the Phosphate Adsorption Results Table:

[0071]

[0072] Recover and dry the modified coal gangue ceramsite adsorption materials for treating phosphorus-containing water bodies that have undergone phosphate adsorption tests, and then perform the second phosphate test and the third phosphate test. The adsorption test results are shown in Table 2, the Recovery Cycle Test Results Table:

[0073]

[0074] As can be seen from the test results in Table 2, compared with the original coal gangue ceramsite in Blank Example 1, the modified coal gangue ceramsite adsorption materials obtained by the four modification methods in Examples 1-3 and Comparative Example 1 have significantly increased adsorption and removal efficiency of phosphate after modification. Moreover, for the removal rate of phosphate, the modification method in Example 1 is significantly better than the modification methods of other comparative examples. As can be seen from the test results in Table 3, the removal rate of phosphate by the modified coal gangue ceramsite adsorption materials in Examples 1-3 is still above 50% in the third time after recycling.

[0075] In the description of this specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0076] The above content is only an example and illustration of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the specific embodiments described or use similar methods to replace them. As long as they do not deviate from the invention or exceed the scope defined by this application, they should all belong to the protection scope of the present invention.

Claims

1. A method for preparing a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water, characterized in that: The following steps are involved: Step 1: weigh the raw materials; wherein the raw materials include the following components by weight: 10 parts of coal gangue ceramsite, 1-20 parts of modifier, 0.1-20 parts of stabilizer, 15-20 parts of deionized water; Step 2, preparing a modified liquid; Step 3, pre-treating the coal gangue ceramsite; Step 4: adding the pretreated coal gangue ceramsite to the modified liquid, and then using a high-speed constant temperature oscillator to perform constant temperature oscillation mixing to obtain pre-modified coal gangue ceramsite; Step 5: Use a cleaning agent to clean the pre-modified coal gangue ceramsite, and then roast it in a muffle furnace to obtain a modified coal gangue ceramsite adsorption material for treating phosphorus-containing water bodies.

2. The method for preparing the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water according to claim 1, characterized in that: The modifier in step 1 includes 1-10 parts of trivalent iron salt and 1-10 parts of trivalent lanthanum salt; The trivalent iron salt includes one or more compounds or hydrated compounds of ferric chloride, ferric sulfate and ferric nitrate; the trivalent lanthanum salt includes one or more compounds or hydrated compounds of lanthanum chloride and lanthanum nitrate.

3. The method for preparing the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water according to claim 1, characterized in that: The stabilizer in step 1 is one or more of sodium hydroxide solution, potassium hydroxide solution, calcium hydroxide solution, barium hydroxide solution and ammonia water with a mass fraction of 10-30%.

4. The method for preparing the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water according to claim 1, characterized in that: The preparation process of the modified solution in step 2 is as follows: The modifier was added into deionized water, stirred at a constant temperature of 40°C and a stirring rate of 300 r / min for 10 min, then the pH was adjusted to 10-11 with a stabilizer, and then ultrasonically treated for 30-90 min at a temperature of 40-60°C and an ultrasonic frequency of 30 kHz to obtain a modified solution.

5. The method for preparing the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water according to claim 1, characterized in that: The pretreatment process of the gangue ceramsite in step 3 is specifically as follows: Soak the gangue ceramsite in an acid solution to activate its surface with acid. After soaking for a certain period of time, use a cleaning agent to clean it three times.

6. The method for preparing the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water according to claim 5, characterized in that: The acidic solution is a 30% by mass HCl solution; the soaking time is ≥24 hours; and the cleaning agent includes one or both of deionized water and ethanol.

7. The method for preparing the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water according to claim 1, characterized in that: The process of the constant temperature oscillation mixing in step 4 is specifically as follows: The pretreated gangue ceramsite is immersed in the modifier at a solid-liquid ratio of 1:8-12, and then a high-speed constant temperature oscillator is used to perform constant temperature oscillation mixing for 6-10 hours at an oscillation rate of 160-240rpm and a temperature of 40°C, and then allowed to stand for 14-18 hours to obtain pre-modified gangue ceramsite.

8. The method for preparing the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water according to claim 1, characterized in that: The process of washing the pre-modified gangue ceramsite in step 5 is specifically as follows: First, wash it three times with anhydrous ethanol, then wash it three times with deionized water, and then dry it in an oven at low temperature.

9. The method for preparing the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water according to claim 8, characterized in that: The drying temperature in the low-temperature drying process is ≤80°C and the drying time is ≤6h.

10. The method for preparing the modified coal gangue ceramsite adsorption material for treating phosphorus-containing water according to claim 1, characterized in that: The roasting process in step 5 is as follows: Heat up from room temperature to 400°C, control the heating time to be 100min, maintain the temperature at 400°C for 3-4h, then cool down with the furnace and take out.

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