Ferric sulfate modified activated aluminum oxide adsorption material and preparation method thereof

Abstract

The invention discloses a preparation method of a ferric sulfate modified activated aluminum oxide adsorption material, which is specifically implemented according to the following steps: step 1, pretreating activated aluminum oxide: step 2, preparing a ferric sulfate solution, adding the activated aluminum oxide pretreated in the step 1 into the ferric sulfate solution, and fully stirring to obtain an impregnation liquid; and 3, precipitating the impregnation liquid prepared in the step 2, carrying out solid-liquid separation on the precipitated impregnation liquid, and treating a solid product obtained by separation of the impregnation liquid to obtain the ferric sulfate modified activated aluminum oxide adsorption material. The invention further discloses a ferric sulfate modified activated aluminum oxide adsorption material. The problems that an existing adsorption material is low in adsorption capacity and large in aluminum oxide consumption are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial wastewater treatment, and specifically relates to an iron sulfate modified activated alumina adsorption material, and also relates to a preparation method of the iron sulfate modified activated alumina adsorption material. Background Art

[0002] With the progress of society, the application of fluorine elements in many modern industries is becoming more and more extensive, inevitably leading to the generation of a large amount of fluorine-containing wastewater. Fluorine-containing wastewater mainly comes from industries such as chemical production, electroplating, photovoltaic industry, glass manufacturing, and metal smelting. The discharge of a large amount of industrial fluorine-containing wastewater further exacerbates the threat of fluorine pollution to the ecological environment and the human living environment. Therefore, treating industrial fluorine-containing wastewater is an important issue faced by various industries at present, and it is an urgent problem to be solved for human health.

[0003] The existing technology for treating fluorine-containing wastewater often uses a combination of precipitation, coagulation, and adsorption methods for treatment, and through technologies such as ion exchange, membrane separation, and electrochemistry, the effluent can meet the industrial reuse standard. However, the composition systems of fluorine-containing wastewater from different sources are very complex, and the content of each component varies greatly. Usually, according to the actual water quality situation, the processing parameters of the precipitant, coagulant, and adsorbent are adjusted to remove fluoride ions in the wastewater. The additives are very easily interfered by the interaction of other ions, hindering their treatment of fluoride ions. The treatment process is complex, the cost of the additives is high, the defluorination effect is poor, the efficiency is low, and it is not practical.

[0004] In order to achieve the efficient treatment of fluorine-containing waste liquid, various adsorbents are used for defluorination, such as activated alumina, activated carbon, synthetic resin, alumina coated with manganese oxide, carbon nanotubes, bone char, kaolinite, etc. Activated alumina has the characteristics of high specific surface area, high porosity, low cost and easy regeneration, and has become an ideal adsorbent material for defluorination. However, when using activated alumina as an adsorbent material to remove fluoride ions, its adsorption capacity is small, and the amount of alumina used is very large, resulting in heavy pressure on the subsequent treatment of filter residue. The defluorination adsorption capacity of modified activated alumina has been improved to varying degrees, but the modification process is relatively complex and not conducive to practical application. There is still room for improvement in the performance of activated alumina during the defluorination process. Previously, some people have studied that rare earth elements lanthanum and cerium have the best affinity for fluorine, so the research on such adsorbents has gradually increased. For example, the Chinese patent "Preparation Method of a Composite Defluorination Material Applied to Defluorination in Electrolytic Zinc Sulfate Solution" (Application Date: September 26, 2014; Application Number: CN201410502929.4; Publication Date: March 11, 2015; Publication Number: CN104399430A) discloses a preparation method of a composite defluorination material applied to defluorination in electrolytic zinc sulfate solution. This composite defluorination material is prepared by pretreating bamboo charcoal through high-temperature heating and sulfuric acid soaking, then impregnating the pretreated bamboo charcoal with a metal salt solution, and after drying, treating it with alkali to precipitate the metal salt in the pores of the bamboo charcoal material. However, the preparation process of this material is complex, and the large amount of rare earth salt used results in high costs; moreover, bamboo charcoal is light in weight and is not easy to come into full contact with the solution during the material preparation and adsorption processes, resulting in difficult operation; in addition, the process of impregnating bamboo charcoal with a metal salt solution, filtering and washing, and then treating it with an alkali solution is prone to cause the loss of the loaded active components. Summary of the Invention

[0005] An object of the present invention is to provide an iron sulfate-modified activated alumina adsorbent material, which solves the problems of low adsorption capacity and large amount of alumina used in existing adsorbent materials.

[0006] Another object of the present invention is to provide a preparation method of the iron sulfate-modified activated alumina adsorbent material.

[0007] The technical solution adopted by the present invention is a preparation method of an iron sulfate-modified activated alumina adsorbent material, which is specifically implemented according to the following steps: Step 1, pretreat the activated alumina: Step 2, prepare an iron sulfate solution, add the activated alumina pretreated in Step 1 to the iron sulfate solution and stir well to obtain an impregnation solution; Step 3, precipitate the impregnation solution prepared in Step 2, perform solid-liquid separation on the precipitated impregnation solution, and treat the solid product obtained by separating the impregnation solution to obtain an iron sulfate-modified activated alumina adsorbent material.

[0008] The characteristics of the present invention also lie in: Step 1 is specifically implemented according to the following steps: Weigh activated alumina particles with a particle size of 1 mm - 2 mm, add the activated alumina particles to deionized water, rinse them repeatedly with deionized water 2 - 3 times, wash them with deionized water until the washing water is no longer turbid, put the washed activated alumina particles into an oven for drying, the drying temperature is 110°C - 120°C, the drying time is 10 h - 11 h, filter after drying, and reserve for natural drying.

[0009] Weigh 5 g - 7 g of the pretreated activated alumina in Step 1.

[0010] Take 50 mL - 55 mL of a ferric sulfate solution with a mass fraction of 2% - 4% in Step 2.

[0011] The stirring time in Step 2 is 4 h - 4.5 h.

[0012] The solid-liquid separation method includes centrifugal separation or evaporation to dryness separation.

[0013] Under normal temperature and pressure, the centrifugation condition is to perform centrifugal rotation at 7000 r / min - 11000 r / min for 5 min - 10 min.

[0014] The evaporation to dryness separation condition is to stir at 80°C - 150°C until the liquid evaporates.

[0015] The obtained solid product is repeatedly rinsed with deionized water until the eluate is clear, the washed solid product is subjected to vacuum drying treatment, and ground into powder to obtain the ferric sulfate-modified activated alumina material.

[0016] The technical solution adopted in the present invention is a ferric sulfate-modified activated alumina adsorption material, with particles having a particle size of 1 mm - 2 mm, a brown appearance, and pores of different sizes distributed on the particle surface, and a BET specific surface area of 314.75 m 2 ·g -1 .

[0017] The beneficial effects of the present invention are as follows: The present invention uses a ferric sulfate solution to modify activated alumina. The modification method is simple and feasible, with low cost and easy operation. The adsorption capacity for fluoride ions is enhanced, which can significantly improve the ability to treat low-concentration fluoride-containing industrial wastewater, and at the same time can also reduce the treatment cost. Description of the Drawings

[0018] Figure 1 is a performance comparison diagram of ferric sulfate-modified activated alumina materials prepared with different mass fractions of ferric sulfate solution in the present invention; Figure 2 is a scanning electron microscope image of activated alumina at 5000 times magnification before modification in Example 7 of the present invention; Figure 3It is the scanning electron microscope image of the iron sulfate-modified activated alumina after modification in Example 7 of the present invention magnified 1000 times; Figure 4 It is the scanning electron microscope image of the activated alumina before modification in Example 7 of the present invention magnified 10000 times; Figure 5 It is the scanning electron microscope image of the iron sulfate-modified activated alumina after modification in Example 7 of the present invention magnified 5000 times. Detailed implementation manners

[0019] Example 1 The preparation method of the iron sulfate-modified activated alumina adsorbent of the present invention is specifically implemented according to the following steps: Step 1, pretreat the activated alumina: Step 2, prepare an iron sulfate solution, add the activated alumina pretreated in Step 1 to the iron sulfate solution and stir well to obtain an impregnation solution; Step 3, precipitate the impregnation solution prepared in Step 2, perform solid-liquid separation on the precipitated impregnation solution, and process the solid product obtained by separating the impregnation solution to obtain the iron sulfate-modified activated alumina adsorbent.

[0020] Example 2 The preparation method of the iron sulfate-modified activated alumina adsorbent of the present invention is specifically implemented according to the following steps: Step 1, pretreat the activated alumina: Weigh activated alumina particles with a particle size of 1 mm - 2 mm, add the activated alumina particles to deionized water, rinse them with deionized water 2 - 3 times, wash them with deionized water until the washing water is no longer turbid, put the washed activated alumina particles into an oven for drying, the drying temperature is 110°C - 120°C, the drying time is 10 h - 11 h, and filter after drying, and leave it for natural drying for standby.

[0021] Step 2, prepare an iron sulfate solution, add the activated alumina pretreated in Step 1 to the iron sulfate solution and stir well to evenly load the iron sulfate metal precursor on the activated alumina particle carrier to obtain an impregnation solution; weigh 5 g - 7 g of the activated alumina pretreated in Step 1; take 50 mL - 55 mL of an iron sulfate solution with a mass fraction of 2% - 4%; the stirring time is 4 h - 4.5 h; Step 3, precipitate the impregnation solution prepared in Step 2, perform solid-liquid separation on the precipitated impregnation solution, and process the solid product obtained by separating the impregnation solution to obtain the iron sulfate-modified activated alumina adsorbent.

[0022] The solid-liquid separation method includes centrifugal separation or evaporation separation; at normal temperature and pressure, the centrifugal condition is 7000r / min~11000r / min for centrifugal rotation, the centrifugal rotation is 5min~10min or the evaporation separation condition is 80℃-150℃ stirring until the liquid evaporates.

[0023] The obtained solid product is repeatedly washed with deionized water until the washing liquid is clear, the washed solid product is vacuum dried and ground into powder to obtain the iron sulfate modified activated alumina material.

[0024] Example 3 The preparation method of the ferric sulfate modified activated alumina adsorption material of the present invention is specifically implemented according to the following steps: Step 1, pre-treatment of activated alumina: Weigh activated alumina particles with a particle size of 1 mm-2 mm, add the activated alumina particles to deionized water, rinse with deionized water repeatedly for 2 times, wash with deionized water until the washing water is no longer turbid, put the cleaned activated alumina particles into an oven for drying at a drying temperature of 110° C. for 10 hours, filter after drying, and dry naturally for use; Step 2, prepare a ferric sulfate solution, add the activated alumina pretreated in step 1 to the ferric sulfate solution and stir thoroughly to make the ferric sulfate metal precursor evenly loaded on the activated alumina particle carrier to obtain an impregnation solution; weigh 5g of the activated alumina pretreated in step 1; take 50mL of 2% ferric sulfate solution by mass; and stir for 4h; Step 3, precipitating the impregnation solution prepared in step 2, performing solid-liquid separation on the precipitated impregnation solution, and treating the solid product obtained by separating the impregnation solution to obtain an iron sulfate modified activated alumina adsorption material.

[0025] The solid-liquid separation method adopts centrifugal separation. Under normal temperature and pressure, the centrifugal condition is 7000r / min for centrifugal rotation for 5min.

[0026] The obtained solid product is repeatedly washed with deionized water until the washing liquid is clear, the washed solid product is vacuum dried and ground into powder to obtain the iron sulfate modified activated alumina material.

[0027] Example 4 The preparation method of the ferric sulfate modified activated alumina adsorption material of the present invention is specifically implemented according to the following steps: Step 1, pre-treatment of activated alumina: Weigh activated alumina particles with a particle size of 1 mm - 2 mm, add the activated alumina particles to deionized water, rinse them repeatedly with deionized water twice, wash them with deionized water until the washing water is no longer turbid, put the washed activated alumina particles into an oven for drying, the drying temperature is 112 °C, the drying time is 10 h, filter after drying, and reserve for natural drying; Step 2, prepare a ferric sulfate solution, add the activated alumina pretreated in Step 1 to the ferric sulfate solution and stir well to obtain an impregnation solution; weigh 5 g of the activated alumina pretreated in Step 1; take 52 mL of a ferric sulfate solution with a mass fraction of 2.5%; the stirring time is 4 h; Step 3, precipitate the impregnation solution prepared in Step 2, perform solid-liquid separation on the precipitated impregnation solution, and process the solid product obtained by separating the impregnation solution to obtain a ferric sulfate-modified activated alumina adsorbent material.

[0028] The solid-liquid separation method uses centrifugal separation; under normal temperature and pressure, the centrifugation condition is to centrifuge at 7500 r / min for 6 min.

[0029] The obtained solid product is repeatedly rinsed with deionized water until the eluate is clear, the washed solid product is subjected to vacuum drying treatment, and ground into powder to obtain a ferric sulfate-modified activated alumina material.

[0030] Example 5 The preparation method of the ferric sulfate-modified activated alumina adsorbent material of the present invention is specifically implemented according to the following steps: Step 1, pretreat activated alumina: Weigh activated alumina particles with a particle size of 1 mm - 2 mm, add the activated alumina particles to deionized water, rinse them repeatedly with deionized water three times, wash them with deionized water until the washing water is no longer turbid, put the washed activated alumina particles into an oven for drying, the drying temperature is 115 °C, the time is 10 h, filter after drying, and reserve for natural drying; Step 2, prepare a ferric sulfate solution, add the activated alumina pretreated in Step 1 to the ferric sulfate solution and stir well to uniformly load the ferric sulfate metal precursor on the activated alumina particle carrier to obtain an impregnation solution; weigh 6 g of the activated alumina pretreated in Step 1; take 53 mL of a ferric sulfate solution with a mass fraction of 3%; the stirring time is 4.1 h; Step 3, precipitate the impregnation solution prepared in Step 2, perform solid-liquid separation on the precipitated impregnation solution, and process the solid product obtained by separating the impregnation solution to obtain a ferric sulfate-modified activated alumina adsorbent material.

[0031] The solid-liquid separation method uses evaporation to dry and separate; the evaporation to dry and separate condition is to stir at 80 °C until the liquid evaporates.

[0032] The obtained solid product was repeatedly rinsed with deionized water until the eluate was clear, and the cleaned solid product was subjected to vacuum drying and ground into powder to obtain the iron sulfate-modified activated alumina material.

[0033] Example 6 The preparation method of the iron sulfate-modified activated alumina adsorption material of the present invention is specifically implemented according to the following steps: Step 1, pretreat the activated alumina: Weigh activated alumina particles with a particle size of 1 mm - 2 mm, add the activated alumina particles to deionized water, rinse them repeatedly with deionized water 3 times, wash with deionized water until the washing water is no longer turbid, put the cleaned activated alumina particles into an oven for drying, the drying temperature is 118 °C, the time is 11 h, filter after drying, and dry naturally for standby; Step 2, prepare an iron sulfate solution, add the pretreated activated alumina in Step 1 to the iron sulfate solution and stir well to obtain an impregnation solution; weigh 6 g of the pretreated activated alumina in Step 1; take 55 mL of an iron sulfate solution with a mass fraction of 3.5%; the stirring time is 4.4 h; Step 3, precipitate the impregnation solution prepared in Step 2, perform solid-liquid separation on the precipitated impregnation solution, and process the solid product obtained by separating the impregnation solution to obtain the iron sulfate-modified activated alumina adsorption material.

[0034] The solid-liquid separation method uses evaporation to separate; the evaporation separation condition is to stir at 150 °C until the liquid evaporates.

[0035] The obtained solid product was repeatedly rinsed with deionized water until the eluate was clear, and the cleaned solid product was subjected to vacuum drying and ground into powder to obtain the iron sulfate-modified activated alumina material.

[0036] Example 7 The preparation method of the iron sulfate-modified activated alumina adsorption material of the present invention is specifically implemented according to the following steps: Step 1, pretreat the activated alumina: Weigh activated alumina particles with a particle size of 1 mm - 2 mm, add the activated alumina particles to deionized water, rinse them repeatedly with deionized water 3 times, wash with deionized water until the washing water is no longer turbid, put the cleaned activated alumina particles into an oven for drying, the oven temperature is 120 °C, the time is 11 h, filter after drying, and dry naturally for standby; Step 2, prepare an iron sulfate solution, add the pretreated activated alumina in Step 1 to the iron sulfate solution and stir well to obtain an impregnation solution; weigh 7 g of the pretreated activated alumina in Step 1; take 55 mL of an iron sulfate solution with a mass fraction of 4%; the stirring time is 4.5 h; Step 3: Precipitate the impregnating solution prepared in Step 2, perform solid-liquid separation on the precipitated impregnating solution, and process the solid product obtained from the separation of the impregnating solution to obtain the iron sulfate-modified activated alumina adsorbent material.

[0037] The solid-liquid separation method uses centrifugal separation; under normal temperature and pressure, the centrifugation conditions are centrifugal rotation at 11,000 r / min for 10 min.

[0038] The obtained solid product is repeatedly rinsed with deionized water until the rinsing liquid is clear, and the cleaned solid product is subjected to vacuum drying treatment and ground into powder. The powder is particles with a particle size of 1 mm - 2 mm, that is, the iron sulfate-modified activated alumina material is obtained.

[0039] The iron sulfate-modified activated alumina materials prepared in the above Examples 3 - 7 are particles with a particle size of 1 mm - 2 mm, and their appearance is brown. The scanning electron microscope results show that there are pores on the surface of the adsorbent, and the BET specific surface area is 314.75 m 2 ·g -1 , which improves the ion exchange capacity and adsorption capacity and shows excellent defluorination ability; the defluorination test of the iron sulfate-modified activated alumina materials prepared in the above Examples 3 - 7 is carried out as follows: Weigh 5 g of the modified activated alumina into a beaker respectively, add it to 100 mL of industrial wastewater with a fluoride ion concentration of 25 mg / L, stir for 1 h, then take samples to measure the remaining fluoride ion concentration in the solution. The detection of fluoride ion concentration uses ion chromatography.

[0040] When preparing the iron sulfate-modified activated alumina materials in Examples 3 - 7, as Figure 1 shown, the mass fractions of the iron sulfate solution in Step 2 are 2%, 2.5%, 3%, 3.5%, and 4% respectively. Calculate the remaining fluoride ion concentration and the removal rate of fluoride ions by the modified activated alumina respectively; Calculate the defluorination rate: Adsorption removal rate (%) = (concentration before adsorption - concentration after adsorption) / concentration before adsorption × 100% (1) From Figure 1 it can be seen that in the modified activated alumina solution with a mass fraction of 3% in Example 5, the remaining fluoride ion concentration is 6.69 mg / L, and the defluorination rate is 91.71%. When the mass fraction in Example 7 is 4%, the defluorination rate can reach 96.58%.

[0041] In the preparation of the iron sulfate-modified activated alumina adsorbent material of the present invention, the activated alumina is modified with an iron sulfate solution, and the process is simple and the cost is low; the defluorination process of the iron sulfate-modified activated alumina is achieved through multiple ways such as adsorption, complexation, chelation, and ion exchange, and the adsorption sites are rich, so it has good adsorption performance.

[0042] The ferric sulfate-modified activated alumina material finally prepared in Example 7 and the pretreated activated alumina material in Step 1 were used as adsorbents for characterization respectively: A fully automatic specific surface area and porosity analyzer (Micromeritics ASAP 2460, USA) was used to measure the specific surface area, average pore diameter, and total pore volume of the adsorbent before and after modification. The working conditions were: temperature 77 K, adsorbate nitrogen, and degassing time 7 h; A scanning electron microscope (ZEISS Sigma 360, Germany) was used to obtain various information of the sample through secondary and backscattered electron signals, via vacuum, electron beam, and imaging system, to characterize the adsorbent before and after modification, with magnification factors of 1000 times, 5000 times, and 10000 times.

[0043] Table 1 is the pore structure parameter table of the ferric sulfate-modified activated alumina of the present invention before and after modification, and the results are as follows respectively:

[0044] It can be seen from Table 1 that the specific surface area of the modified activated alumina prepared in Example 7 is 314.75 m 2 ·g -1 , the average pore diameter is 5.34 nm, and the total pore volume is 0.033 cm 2 ·g -1 . Compared with the unmodified activated alumina material in Step 1, its specific surface area and average pore diameter have both increased; The unmodified activated alumina material is as shown in Figure 2 and Figure 4 . It was observed that the piled-up particles on the surface of the activated alumina are relatively large and there is no obvious pore structure. After modification with ferric sulfate, the particle surface of the activated alumina is rougher, as shown in Figure 3 and Figure 5 . The specific surface area is larger, which is consistent with the BET result analysis. Thus, the adsorption capacity of the modified activated alumina is increased, and pores of different sizes are distributed on the modified activated alumina particles, with good porosity. This indicates that there are more adsorption sites on the surface of the modified activated alumina, enhancing the adsorption ability for fluoride ions and solving the problems of low adsorption capacity and large consumption of alumina existing in the existing adsorption materials.

Claims

1. A method for preparing an activated alumina adsorption material modified by ferric sulfate, characterized in that: Follow the steps below to implement it: Step 1, pre-treatment of activated alumina: Step 2, preparing a ferric sulfate solution, adding the activated alumina pretreated in step 1 into the ferric sulfate solution and stirring sufficiently to obtain an impregnation solution; Step 3, precipitating the impregnation solution prepared in step 2, performing solid-liquid separation on the precipitated impregnation solution, and treating the solid product obtained by separating the impregnation solution to obtain an iron sulfate modified activated alumina adsorption material.

2. The method for preparing the ferric sulfate modified activated alumina adsorption material according to claim 1 is characterized in that: The step 1 is specifically implemented according to the following steps: weighing activated alumina particles with a particle size of 1mm-2mm, adding the activated alumina particles into deionized water, repeatedly rinsing with deionized water for 2-3 times, washing with deionized water until the washing water is no longer turbid, placing the cleaned activated alumina particles in an oven for drying at a drying temperature of 110°C-120°C for a drying time of 10 h-11 h, filtering after drying, and drying naturally for use.

3. The method for preparing the ferric sulfate modified activated alumina adsorbent material according to claim 2, characterized in that: In the step 2, weigh 5g-7g of the pre-treated activated alumina in step 1.

4. The method for preparing the ferric sulfate modified activated alumina adsorbent material according to claim 2, characterized in that: In step 2, take 50mL-55mL of 2%-4% ferric sulfate solution.

5. The method for preparing the ferric sulfate modified activated alumina adsorbent material according to claim 2, characterized in that: The stirring time of step 2 is 4h-4.5h.

6. The method for preparing the ferric sulfate modified activated alumina adsorption material according to claim 2, characterized in that: The solid-liquid separation method includes centrifugal separation or evaporation separation.

7. The method for preparing the ferric sulfate modified activated alumina adsorbent material according to claim 2, characterized in that: Under normal temperature and pressure conditions, the centrifugal condition is 7000r / min~11000r / min for centrifugal rotation, and the centrifugal rotation is 5min~10min.

8. The method for preparing the ferric sulfate modified activated alumina adsorbent material according to claim 2, characterized in that: The evaporation and separation conditions are stirring at 80°C-150°C until the liquid evaporates.

9. The method for preparing the ferric sulfate modified activated alumina adsorbent material according to claim 2, characterized in that: The obtained solid product is repeatedly washed with deionized water until the washing liquid is clear, the washed solid product is vacuum dried and ground into powder to obtain the iron sulfate modified activated alumina material.

10. Ferric sulfate modified activated alumina adsorption material, characterized in that: The particles are 1mm-2mm in size, brown in appearance, with pores of different sizes distributed on the surface of the particles, and a BET specific surface area of ​​314.75 m 2 ·g -1 .

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