CN115501852A - Preparation method and application of metal-doped alumina hydrate with high adsorption performance - Google Patents

Abstract

The invention discloses a preparation method and application of metal-doped alumina hydrate with high adsorption performance, wherein the method comprises the following steps: s1, preparing a metal salt solution: mixing metal salt with deionized water to form a uniform metal salt solution; s2, preparing a sodium metaaluminate solution: taking NaAlO ₂ Mixing with deionized water, stirring until the mixture is completely dissolved, adding ethylene glycol, and stirring uniformly again to form a sodium metaaluminate solution; s3, preparing a metal-doped alumina hydrate material: and (2) diluting the metal salt solution, mixing the diluted metal salt solution with a sodium metaaluminate solution, and then sequentially stirring and mixing, carrying out hydrothermal reaction, centrifuging, washing and drying to obtain the metal-doped alumina hydrate material. Andcompared with a single alumina hydrate material, the prepared metal-doped alumina hydrate material has the advantages that the adsorption performance of the material on Roxarsone (ROX) solution is obviously improved, and the adsorption capacity of the material on ROX is obviously improved.

Description

Preparation method and application of metal-doped alumina hydrate with high adsorption performance

technical field

The invention belongs to the technical field of composite material synthesis, and in particular relates to a preparation method and application of a metal-doped alumina hydrate with high adsorption performance.

Background technique

3-nitro-4-hydroxyphenylarsonic acid (roxarsarsenic, ROX) belongs to a kind of aromatic organic arsenic, and is a new type of organic-inorganic composite arsenic pollutant. With the development of industry, ROX is widely used as livestock feed additives and pesticide additives. This type of organic arsenic compounds will enter the environment with livestock manure and soil, and will be transformed into more toxic inorganic substances under the action of microorganisms or photodegradation. Arsenic poses safety hazards to the ecological environment and human health [Chen W R, Huang C H. Surface adsorption of organoarsenic roxarsone and arsanilic acid on iron and aluminum oxides [J]. Journal of Hazardous Materials, 2012, 227: 378-385]. With the development of industrialization, arsenic pollution in groundwater has become a global crisis, and the global standards for the concentration of arsenic in water are becoming increasingly stringent, such as the arsenic wastewater discharge standard of 0.5 mg/g, and the standard of arsenic content in drinking water of 10 μg/L . Therefore, finding suitable means to deal with organic arsenic, a new type of pollutant, has become the focus of work in related fields.

K,

J,Ranganathan S,et al.Photocatalytic degradation of roxarsone by usingsynthesized ZnO nanoplates[J].Solar Energy,2017,157:335-341.]采用湿式化学法合成ZnO纳米板，并在紫外光照射下实现了ROX的有效光降解，在ZnO浓度为2.5g/L，ROX浓度为15mg/L的条件下实现了70％的降解效率；可能的光催化机理为ROX的光催化降解导致矿化为CO₂和As(V)。Wan-Ru Chen等人[Chen W R,Huang C H.Surface adsorption oforganoarsenic roxarsone and arsanilic acid on iron and aluminum oxides[J].Journal ofHazardous Materials,2012,227:378-385]研究了ROX和ASA对铁和氧化铝的表面吸附，发现各种无机砷酸盐能迅速、大量地吸附在各种铁和铝氧化物上，而对于ROX，由于其砷酸基团，芳香族砷也可能强烈地吸附在铁和铝氧化物上。然而，文中纯金属氧化物的最终吸附容量并不令人满意。The preparation of roxars arsenic adsorbent mainly utilizes metal coordination, complexation and the formation of hydrogen bonds and oxygen vacancies and other mechanisms. At present, the commonly used adsorption materials for removing organic arsenic in water in related research fields include activated carbon, agricultural waste, metal Oxides, mineral clays, nanomaterials, and molecular sieves, etc. Wentao Fu et al.[FuW,Lu DL,Yao H,et al.Simultaneous roxarsone photocatalytic degradation and arsenic adsorption removal by TiO ₂ /FeOOH hybrid[J].Environmental Science and Pollution Research,2020,27(15):18434-18442.] A bifunctional titanium dioxide/iron hydrate (TiO ₂ /FeOOH) hybrid was synthesized by a hydrothermal method, which simultaneously photocatalytically degraded rosapine and released arsenic adsorption, and was developed at an adsorbent concentration of 0.1 g/L and a ROX concentration of 10 mg/ Under the adsorption condition of L, the arsenic adsorption removal rate of 96% was obtained. The main adsorption mechanism is to release As(V) through the catalytic degradation of ROX through the abundant hydroxyl groups on the surface of the adsorbent, and the released As(V) is quickly absorbed and removed by FeOOH added to the TiO ₂ /FeOOH hybrid, and the released As(V) Inorganic arsenic ions are adsorbed. The studied TiO ₂ /FeOOH hybrid has good stability and reliability, and a possible mechanism for the hybrid to degrade roxapine and release inorganic arsenic is proposed. The disadvantage is that the preparation temperature of the adsorbent is high and the preparation cycle is long , The preparation process is relatively complicated (180°C, 12h), and the removal of high-concentration ROX solution has not been studied. Furthermore, Paola Santander et al. [

K,

J,Ranganathan S,et al.Photocatalytic degradation of roxarsone by using synthesized ZnO nanoplates[J].Solar Energy,2017,157:335-341.] ZnO nanoplates were synthesized by wet chemical method, and ROX was realized under ultraviolet light irradiation 70% degradation efficiency was achieved under the conditions of ZnO concentration of 2.5g/L and ROX concentration of 15mg/L; the possible photocatalytic mechanism is that the photocatalytic degradation of ROX leads to mineralization into CO ₂ and As (V). Wan-Ru Chen et al [Chen WR, Huang C H.Surface adsorption of organoarsenic roxarsone and arsanilic acid on iron and aluminum oxides[J].Journal of Hazardous Materials,2012,227:378-385] studied the effects of ROX and ASA on iron and aluminum oxides Surface adsorption of alumina, it was found that various inorganic arsenates can be rapidly and massively adsorbed on various iron and aluminum oxides, while for ROX, aromatic arsenic may also strongly adsorb on iron due to its arsenate group and aluminum oxide. However, the final adsorption capacity of pure metal oxides in this paper is not satisfactory.

In summary, because the existing ROX adsorption materials often have problems such as complex preparation process, high energy consumption, and low adsorption capacity, it is urgent to find a method to cleanly prepare adsorption materials with high adsorption performance using cheap raw materials under mild conditions. question.

Contents of the invention

In view of the problems existing in the prior art, the object of the present invention is to provide a metal-doped modified alumina hydrate adsorbent material that is easy to prepare, easy to obtain raw materials, environmentally friendly, and has excellent adsorption performance for ROX and its preparation method .

The object of the present invention adopts following technical scheme to realize:

In the first aspect, the present invention provides a method for preparing metal-doped alumina hydrate with high adsorption performance, which uses a one-step hydrothermal method to prepare metal-doped alumina hydrate with high adsorption performance, comprising the following steps:

Step S1, preparing metal salt solution:

Mix the metal salt with deionized water to form a uniform metal salt solution;

Step S2, preparing sodium metaaluminate solution:

Mix NaAlO ₂ with deionized water, stir until completely dissolved, add ethylene glycol, and stir again to form a sodium metaaluminate solution;

Step S3, preparing metal-doped alumina hydrate material:

After diluting the metal salt solution, mixing it with the sodium metaaluminate solution, stirring and mixing, hydrothermal reaction, centrifugation, washing and drying, the metal-doped alumina hydrate material is obtained.

Preferably, the metal salt solution in the step S1 includes one of Na ₂ ZnO ₂ solution, FeCl ₃ solution and CuCl ₂ solution.

Preferably, the preparation process of the _Na2ZnO2 solution is _:

Dissolve NaOH in deionized water, stir until completely dissolved, gradually add ZnO while heating up, when all ZnO is added, raise the temperature of the solution to boiling; then keep warm and keep stirring until the solution becomes clear, stop heating, cool naturally, and lower the temperature After reaching room temperature, it was diluted to obtain a Na ₂ ZnO ₂ solution.

Preferably, during the preparation of the Na ₂ ZnO ₂ solution, the mass ratio of ZnO, NaOH and deionized water is 10:23.2:20.

Preferably, described FeCl _The preparation process of solution is:

Dissolve _FeCl3 in deionized water and stir until completely dissolved to obtain _FeCl3 solution.

Preferably, during the preparation _of the FeCl3 solution, the mass ratio _of FeCl3 to deionized water is 5.95:20.

Preferably, the preparation process of the _CuCl solution is:

Dissolve CuCl ₂ ·2H ₂ O in deionized water and stir until completely dissolved to obtain a CuCl ₂ solution.

Preferably, during the preparation of the CuCl ₂ solution, the mass ratio of CuCl ₂ ·2H ₂ O to deionized water is 6.2:20.

Preferably, in the step S2, the mass ratio of NaAlO ₂ , deionized water and ethylene glycol is 1.2:15:25.

Preferably, in the step S3, the dilution process of the metal salt solution is as follows: the metal salt solution and deionized water are mixed in a volume ratio of 4:6.

Preferably, in the step S3, the diluted metal salt solution is mixed with the sodium metaaluminate solution at a volume ratio of 10:40.

Preferably, in the step S3, the temperature of the hydrothermal reaction is 60° C., the washing is performed three times with deionized water and then once with absolute ethanol, and the drying is performed in a drying oven at 60° C. for 24 hours.

In the second aspect, the present invention provides the metal-doped alumina hydrate with high adsorption performance prepared by the aforementioned method as the adsorption material of rosa pine ROX.

The preparation method provided by the present invention and the application of metal-doped alumina hydrate with high adsorption performance have the beneficial effects of:

(1) The preparation environment of the metal-doped alumina hydrate composite material is mild, the operation is simple and the preparation process is environmentally friendly, and the aluminum source NaAlO ₂ is cheap and easy to obtain.

(2) The adsorption performance of the metal-doped alumina hydrate material prepared by the present invention to ROX solution is significantly improved, and compared with the single alumina hydrate material, its adsorption capacity to ROX is significantly improved.

Description of drawings

The present invention is further described by using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. For those of ordinary skill in the art, without paying creative work, other embodiments can also be obtained according to the following accompanying drawings Attached picture.

Fig. 1 is the XRD pattern of the metal-doped alumina hydrate prepared in embodiment 1-6;

2 is an enlarged view of the XRD spectrum of the metal-doped alumina hydrate prepared in Examples 1-4;

Fig. 3 is when the concentration of initial ROX is 100mg/g, the adsorption kinetic curve of the metal-doped alumina hydrate that embodiment 1-6 prepares;

Fig. 4 is the adsorption isotherm of the metal-doped alumina hydrate prepared in Example 5.

detailed description

In order to illustrate the present invention more clearly and have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solutions of the present invention are now described in detail below, but it cannot be interpreted as limiting the scope of the present invention.

Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial channels, or can be obtained by existing known methods. The raw materials involved in the following examples are all available from commercial sources. The room temperature referred to in each embodiment of the experimental process of the present invention is 25°C.

Self-made sodium aluminate solution: Dissolve 1.2 g of sodium aluminate in 15 mL of deionized water at room temperature, and form a solution after magnetic stirring. The concentration of the sodium aluminate solution is 0.97 mol/L.

Self-made sodium zincate solution: Dissolve 23.2g of NaOH in 20mL of deionized water at room temperature, and stir until completely dissolved. While heating the above solution, add 10g of ZnO in batches 5 times successively. When all the ZnO is added, heat the solution to a slight boiling; continue heating until the solution gradually becomes clear, then cool it down, stir to room temperature and dilute the solution to 40mL , the concentration of sodium zincate obtained is 1.83mol/L, and it is diluted to different concentrations as required when preparing the samples of the examples.

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Example 1:

The preparation method of metal-doped alumina hydrate with high adsorption performance provided by the embodiment of the present invention is to prepare metal-doped alumina hydrate with high adsorption performance by a one-step hydrothermal method, which specifically includes the following steps:

Step S1, preparing metal salt solution:

Mix the metal salt with deionized water to form a uniform metal salt solution;

Step S2, preparing sodium metaaluminate solution:

Mix NaAlO ₂ with deionized water, stir until completely dissolved, add ethylene glycol, and stir again to form a sodium metaaluminate solution;

Step S3, preparing metal-doped alumina hydrate material:

After diluting the metal salt solution, mixing it with the sodium metaaluminate solution, stirring and mixing, hydrothermal reaction, centrifugation, washing and drying, the metal-doped alumina hydrate material is obtained.

Specifically, the following steps are included:

S1: Take 15mL of self-made sodium aluminate solution in a beaker at room temperature, quickly add 25mL of ethylene glycol, stir magnetically for 1 minute to form a uniform clear liquid, then add 10mL of deionized water to the above system, and stir vigorously for 2 minutes;

S2: Put the above reaction system in an oven at 60°C for 4 hours, centrifuge the reacted mixture, wash it with deionized water for 3 times, wash it with ethanol once, and dry it in a drying oven at 60°C for 24 hours to obtain A sample of doped hydrated alumina, labeled AlOOH.

S3: Adsorb the sample with 50 mL of ROX solution with an initial concentration of 100 mg/L. Prepare 50mL of ROX solution with an initial concentration of 100mg/L, add 20mg of the above sample, and place it in a shaking box for adsorption for 12h. The equilibrium adsorption capacity of the sample under this condition is measured to be 142.3mg/g.

Example 2:

The preparation method and application of the metal-doped alumina hydrate with high adsorption performance provided in this example are basically the same as in Example 1, except that it includes the following steps:

S1: Disperse 6.20 g of copper chloride dihydrate in 20 mL of deionized water at room temperature;

S2: Take 15mL self-made sodium aluminate solution in a beaker at room temperature, quickly add 25mL ethylene glycol, and magnetically stir for 1min to form a uniform clear solution;

S3: Take 4.0 mL of the copper chloride solution obtained in step (1), dilute it to 10 mL, and then add it dropwise to the reaction system described in step (2); after stirring vigorously for 2 minutes, place the reaction system in an oven at 60°C Hydrothermal for 4 h; washed with deionized water for 3 times and then with ethanol for 1 time, followed by drying in a drying oven at 60 °C for 24 h to obtain Cu-doped samples. XRD analysis shows that the copper in the sample exists as copper oxide-copper hydroxide, and the aluminum exists as amorphous hydrated alumina; the metal-doped alumina hydrate sample is marked as CuO/AlOOH;

S4: Use the sample to absorb 50 mL of ROX solution with an initial concentration of 100 mg/L. Prepare 50mL of ROX solution with an initial concentration of 100mg/L, add 20mg of the above sample, and place it in a shaking box for adsorption for 12h. The equilibrium adsorption capacity of the sample under this condition is measured to be 183.3mg/g.

Example 3:

The preparation method and application of the high-adsorption performance metal-doped alumina hydrate provided in this example are basically the same as those in Examples 1 and 2, except that the following steps are included:

S1: Disperse 5.95g of ferric chloride in 20mL of deionized water at room temperature;

S2: Take 15mL self-made sodium aluminate solution in a beaker at room temperature, quickly add 25mL ethylene glycol, and magnetically stir for 1min to form a uniform clear liquid;

S3: Take 4.0 mL of the ferric chloride solution obtained in step (1), dilute it to 10 mL, and then add it dropwise to the reaction system described in step (2); after stirring vigorously for 2 minutes, place the reaction system in an oven at 60°C , hydrothermal for 4h; washed with deionized water for 3 times and then with ethanol for 1 time, and then dried in a 60°C drying oven for 24h to obtain Fe-doped samples. XRD analysis shows that the sample is a composite material of amorphous phase hydrated iron oxide and amorphous phase hydrated alumina; the metal-doped alumina hydrate sample is marked as FeOOH/AlOOH.

S4: Adsorb the sample with 50 mL of ROX solution with an initial concentration of 100 mg/L. Prepare 50mL of ROX solution with an initial concentration of 100mg/L, add 20mg of the above sample, and place it in a shaking box for adsorption for 12h. The equilibrium adsorption capacity of the sample under this condition is measured to be 198.1mg/g.

Example 4:

The preparation method and application of the high-adsorption performance metal-doped alumina hydrate provided in this example are basically the same as those in Examples 1-3, except that the following steps are included:

(1) Take 15 mL of homemade sodium aluminate solution in a beaker at room temperature, quickly add 30 mL of ethylene glycol, and stir magnetically for 1 min to form a uniform clear liquid;

(2) Take 0.5mL self-made sodium zincate solution, first dilute to 10mL, and then add dropwise to the reaction solution described in step (1); after stirring vigorously for 2min, place the reaction system in a 70°C oven for 2h; The Zn-doped samples were obtained by washing with deionized water for 3 times and then with ethanol for 1 time, and then drying in a 60°C drying oven for 24 h. XRD analysis showed that the sample was a composite material of zinc oxide and alumina hydrate in amorphous phase; the metal-doped alumina hydrate sample was labeled as ZnO/AlOOH-1.

(3) Use the sample to absorb 50 mL of ROX solution with an initial concentration of 100 mg/L. Prepare 50mL of ROX solution with an initial concentration of 100mg/L, add 20mg of the above sample, and place it in a shaking box for adsorption for 12h. The equilibrium adsorption capacity of the sample under this condition is measured to be 166.3mg/g.

Example 5:

The preparation method and application of the high-adsorption performance metal-doped alumina hydrate provided in this example are basically the same as those in Examples 1-4, except that the following steps are included:

(1) Take 15 mL of homemade sodium aluminate solution in a beaker at room temperature, quickly add 30 mL of ethylene glycol, and stir magnetically for 1 min to form a uniform clear liquid;

(2) Take 2 mL of self-made sodium zincate solution, dilute it to 10 mL, and then add it dropwise to the reaction solution described in step (1); after stirring vigorously for 2 minutes, place the reaction system in a 60°C oven for 4 hours; The Zn-doped samples were obtained by washing with deionized water for 3 times and then with ethanol for 1 time, and drying in a drying oven at 60 °C for 24 h. The sample is a composite material of zinc oxide and alumina hydrate in amorphous phase; the metal-doped alumina hydrate sample is marked as ZnO/AlOOH-2.

(3) Adsorb the sample with 50 mL of ROX solution with an initial concentration of 100 mg/L. Prepare 50mL of ROX solution with an initial concentration of 50mg/L, add 20mg of the above sample, and place it in a shaking box for adsorption for 12h. The equilibrium adsorption capacity of the sample under this condition is measured to be 237.7mg/g.

Embodiment 6:

The preparation method and application of the high-adsorption performance metal-doped alumina hydrate provided in this example are basically the same as those in Examples 1-5, except that the following steps are included:

(1) Take 15mL of homemade sodium aluminate solution in a beaker at room temperature, quickly add 20mL of ethylene glycol, and magnetically stir for 1min to form a uniform clear liquid;

(2) Take 4 mL of self-made sodium zincate solution, dilute it to 10 mL, and then add it dropwise to the reaction solution described in step (1); after stirring vigorously for 2 minutes, place the reaction system in an oven at 50°C for 8 hours; The Zn-doped samples were obtained by washing with deionized water for 3 times and then with ethanol for 1 time, and drying in a drying oven at 60 °C for 24 h. The sample is a composite material of zinc oxide and alumina hydrate in amorphous phase; the metal-doped alumina hydrate sample is marked as ZnO/AlOOH-3.

(3) Adsorb the sample with 50 mL of ROX solution with an initial concentration of 100 mg/L. Prepare 50mL of ROX solution with an initial concentration of 100mg/L, add 20mg of the above sample, and place it in a shaking box for adsorption for 12h. The equilibrium adsorption capacity of the sample under this condition is measured to be 236.5mg/g.

Application Example 7:

In order to investigate the adsorption capacity of the metal-doped boehmite for ROX solutions with different concentrations, the adsorbent ZnO/AlOOH-2 prepared in Example 5 was taken as an example to test its adsorption performance for ROX solutions with different initial concentrations. The adsorption process is as follows: prepare 50mL of ROX solutions with concentrations of 20mg/L, 100mg/L, 300mg/L, 500mg/L, and 1000mg/L respectively, then add 0.02g of ZnO/AlOOH-2 respectively, and place them in the shaking box After 12 hours of adsorption, use a UV spectrophotometer to measure the adsorption effect. The parameters of the constant temperature oscillation box are set at 25°C and 150r/min. The adsorption isotherm of the sample ZnO/AlOOH-2 prepared in Example 5 is shown in Figure 3, which is better The adsorption capacity was 1110.8 mg/g.

Among them, in order to illustrate the present invention more clearly, the present invention also lists the following tables, Table 1 shows the preparation of the precursor solution of Examples 1-6 and the comparison of samples; Table 2 is the metal-doped samples prepared in Examples 1-6 Comparison of the equilibrium adsorption capacity and adsorption removal rate of alumina hydrate samples on ROX; Table 3 is the adsorption comparison of Example 2 on different initial ROX concentrations.

Table 1 Example 1 ~ 6 precursor solution preparation and sample comparison

The comparison of table 2 embodiment 1～6 to the equilibrium adsorption capacity of ROX and adsorption removal rate

Table 3 Example 2 compares the equilibrium adsorption capacity of different initial ROX concentrations

C₀(mg/L) 20 100 300 500 1000 Equilibrium adsorption capacity (mg/g) 42.9 237.7 712.5 1110.8 1091.1

The preparation method and the application of the metal-doped alumina hydrate with high adsorption performance provided by the above-mentioned embodiments of the present invention, the preparation environment of the metal-doped alumina hydrate composite material is mild, the operation is simple, and the preparation process is environmentally friendly. The aluminum source NaAlO ₂ Cheap and easy to obtain; the metal-doped alumina hydrate material prepared by the invention has significantly improved adsorption performance on ROX solution, and compared with single alumina hydrate material, its adsorption capacity on ROX has been significantly improved.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand , the technical solution of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present invention.

Claims (10)

1. A preparation method of metal-doped alumina hydrate with high adsorbability is characterized in that the metal-doped alumina hydrate with high adsorbability is prepared by a one-step hydrothermal method, and comprises the following steps:

s1, preparing a metal salt solution:

mixing metal salt with deionized water to form a uniform metal salt solution;

s2, preparing a sodium metaaluminate solution:

taking NaAlO ₂ Mixing with deionized water, stirring until the mixture is completely dissolved, adding ethylene glycol, and stirring uniformly again to form a sodium metaaluminate solution;

s3, preparing a metal-doped alumina hydrate material:

and (2) diluting the metal salt solution, mixing the diluted metal salt solution with a sodium metaaluminate solution, and then sequentially stirring and mixing, carrying out hydrothermal reaction, centrifuging, washing and drying to obtain the metal-doped alumina hydrate material.

2. The method for preparing a metal-doped aluminum oxide hydrate with high adsorbability according to claim 1, wherein the metal salt solution in the step S1 includes Na ₂ ZnO ₂ Solution, feCl ₃ Solution and CuCl ₂ One of the solutions.

3. The method for preparing metal-doped alumina hydrate with high adsorbability according to claim 2, wherein the Na is ₂ ZnO ₂ The preparation process of the solution is as follows:

dissolving NaOH in deionized water, stirring until the NaOH is completely dissolved, gradually adding ZnO while heating, and heating the solution to boiling after the ZnO is completely added; then keeping the temperature and continuously stirring until the solution becomes clear, stopping heating, naturally cooling, cooling to room temperature, diluting to obtain Na ₂ ZnO ₂ A solution; wherein, the Na ₂ ZnO ₂ During the preparation of the solution, the mass ratio of ZnO, naOH and deionized water is 10.

4. The method of claim 2, wherein the FeCl is the source of the high adsorptive capacity metal-doped alumina hydrate ₃ The preparation process of the solution is as follows:

taking FeCl ₃ Dissolving in deionized water, stirring to completely dissolve to obtain FeCl ₃ A solution;

wherein the FeCl ₃ In the preparation of the solution, feCl ₃ The mass ratio to deionized water was 5.95.

5. The method of claim 1, wherein the CuCl is added to the metal-doped alumina hydrate ₂ The preparation process of the solution is as follows:

taking CuCl ₂ ·2H ₂ Dissolving O in deionized water, stirring to completely dissolve to obtain CuCl ₂ A solution;

wherein, the CuCl ₂ In the preparation of the solution, cuCl ₂ ·2H ₂ The mass ratio of O to deionized water was 6.2.

6. The method for preparing metal-doped aluminum oxide hydrate with high adsorbability according to claim 1, wherein in the step S2, naAlO is added ₂ The mass ratio of the deionized water to the ethylene glycol is 1.2.

7. The method for preparing metal-doped alumina hydrate with high adsorbability according to claim 1, wherein the dilution treatment process of the metal salt solution in the step S3 is as follows: the metal salt solution was mixed with deionized water at a volume ratio of 4.

8. The method for preparing a metal-doped alumina hydrate with high adsorbability according to claim 1, wherein in the step S3, the diluted metal salt solution and the sodium metaaluminate solution are mixed in a volume ratio of 10.

9. The method for preparing the metal-doped alumina hydrate with high adsorbability according to claim 1, wherein the temperature of the hydrothermal reaction in step S3 is 60 ℃, the washing is performed by washing 3 times with deionized water and then washing 1 time with absolute ethanol, and the drying is performed in a drying oven at 60 ℃ for 24 hours.

10. Use of a metal-doped alumina hydrate with high adsorption performance as a rocky arsenic (ROX) adsorption material, wherein the metal-doped alumina hydrate prepared by the preparation method of any one of claims 1 to 9.

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