Halloysite-supported cerium-manganese composite material, its preparation method and applications

Abstract

This invention provides a halloysite-supported cerium-manganese composite material, its preparation method, and its applications, belonging to the field of adsorption material preparation technology. The invention involves adding halloysite powder to deionized water and dispersing it by stirring at room temperature. Then, cerium material and potassium permanganate are added, followed by dilute sulfuric acid. The mixture is heated and stirred, then cooled, and sodium hydroxide solution is added dropwise. After solid-liquid separation, the solid is dried and ground to obtain the halloysite-supported cerium-manganese composite material. This adsorption material can co-adsorb arsenic and antimony, exhibiting high removal rates for both. The material prepared by this invention uses the natural clay mineral halloysite as the base material and cerium nitrate and potassium permanganate as modifiers. The leaching of cerium and manganese is negligible, making it environmentally friendly. Furthermore, the amount of cerium and manganese released into the environment during material use is very small, preventing secondary pollution.

Description

Technical Field

[0001] This invention relates to the field of adsorption material preparation technology, and in particular to an halloysite-supported cerium-manganese composite material, its preparation method, and its applications. Background Technology

[0002] Arsenic (As) is a recognized carcinogen. It is widely distributed in nature, and its oxides and arsenates are highly toxic, with trivalent arsenic being more toxic than pentavalent arsenic. When handling arsenic compounds, improper protective measures can lead to arsenic poisoning through inhalation, skin, and digestion. Arsenic exists primarily in wastewater in compound form, exhibiting high toxicity to aquatic organisms and readily accumulating within them.

[0003] Antimony is a non-renewable metal. Antimony and its compounds are widely used in various industrial fields. Antimony is not an essential element for living organisms and has cumulative toxicity and carcinogenicity.

[0004] Existing technologies for adsorbing arsenic and antimony in water have high costs, low adsorption efficiency, and cause secondary pollution, and also have low adsorption performance for trivalent arsenic and antimony. Summary of the Invention

[0005] In view of this, the present invention provides a method for preparing halloysite-supported cerium-manganese composite material. The prepared material has low cost, is environmentally friendly, has fast adsorption speed and high efficiency, and has an oxidative adsorption effect on trivalent arsenic and antimony, which can reduce the toxicity of trivalent arsenic and antimony in the environment.

[0006] The method for preparing halloysite-supported cerium-manganese composite material of the present invention includes the following steps:

[0007] (1) Add halloysite powder to deionized water and stir and disperse at room temperature for 20-25 minutes. Add cerium material and potassium permanganate, and then add dilute sulfuric acid.

[0008] (2) Heat to 75-85℃ and stir for 12 hours, then cool and add sodium hydroxide solution dropwise after cooling;

[0009] (3) Perform solid-liquid separation on the solution in step (2);

[0010] (4) The solid separated from the liquid is dried at 80°C for 6 hours or more and then ground to obtain the product, which is halloysite-supported cerium-manganese composite material.

[0011] Preferably, the cerium material in step (1) accounts for 5-25% of halloysite by mass, and the cerium material is cerium nitrate hexahydrate.

[0012] Preferably, in step (1), cerium material and potassium permanganate are added in a cerium-manganese molar ratio of 2:1 to 6:1.

[0013] Preferably, in step (1), dilute sulfuric acid is added until the pH value is 1-3.

[0014] Preferably, the pH value of the sodium hydroxide solution added in step (2) is 10-11.

[0015] Preferably, step (3) achieves solid-liquid separation by vacuum filtration, and deionized water is added during the vacuum filtration process to wash until the filtrate is neutral.

[0016] Another object of the present invention is to provide a halloysite-supported cerium-manganese composite material prepared by the above method.

[0017] Another object of the present invention is to provide a use of the halloysite-supported cerium-manganese composite material in adsorbing arsenic and antimony in wastewater.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention provides a halloysite-supported cerium-manganese composite material, its preparation method, and its applications. For water bodies with an arsenic content of 10 mg / L and an antimony content of 20 mg / L, when the dosage of pentavalent arsenic-antimony adsorbent is 0.5 g / L (i.e., 0.5 g of adsorbent per 1 L of wastewater) and the dosage of trivalent arsenic-antimony adsorbent is 1.0 g / L (i.e., 1.0 g of adsorbent per 1 L of wastewater), the removal rates of pentavalent arsenic, trivalent, and pentavalent antimony can all reach adsorption equilibrium within 6 hours, with a final removal rate exceeding 95%.

[0020] The adsorbent material of this invention can co-adsorb arsenic and antimony, exhibiting high removal rates for both. Adsorption equilibrium for pentavalent arsenic, trivalent, and pentavalent antimony can be reached within 6 hours, with final removal rates exceeding 95%. The material prepared by this invention is environmentally friendly, solving the problem of secondary pollution. The material uses halloysite, a natural clay mineral, as the base material, and cerium nitrate and potassium permanganate as modifiers. Cerium and manganese leaching is negligible and harmless to the environment. Furthermore, the material releases very little cerium and manganese into the environment during use, preventing secondary pollution. Attached Figure Description

[0021] Figure 1 The XRD patterns of halloysite-supported cerium-manganese composites in Example 1 and Comparison 1 are shown.

[0022] Figure 2 The relationship between contact time and removal rate of four arsenic and antimony anions adsorbed by halloysite-supported cerium-manganese composite material in Example 1 is shown. Detailed Implementation

[0023] The present invention will be further described below with reference to the embodiments.

[0024] Example 1

[0025] A method for preparing halloysite-supported cerium-manganese composite material, comprising the following steps:

[0026] (1) Add halloysite to deionized water and stir and disperse at room temperature for 20 min. Add cerium material (cerium nitrate hexahydrate) and potassium permanganate (cerium-manganese ratio of 3:1). Then add dilute sulfuric acid to adjust the pH of the solution to 1. The cerium material accounts for 25% of the mass fraction of halloysite.

[0027] (2) Heat to 80℃ and stir for 12 hours, then cool. After cooling, add sodium hydroxide solution dropwise to adjust the pH to 10.5.

[0028] (3) The solution in step (2) is separated into solid and liquid by vacuum filtration. During the vacuum filtration process, sufficient deionized water is added to wash until the filtrate is neutral, and residual sodium hydroxide and sulfate ions are washed away.

[0029] (4) The solid separated from the liquid is dried at 80°C for 6 hours and ground. The product obtained is halloysite-supported cerium-manganese composite material, denoted as HNT@25CeMn.

[0030] Comparative Example 1

[0031] A method for preparing halloysite-supported cerium-manganese composite material, the steps of which are as described in Example 1;

[0032] The difference is that in step (1) of Comparative Example 1, 10% by mass of cerium material is added, and the halloysite-supported cerium-manganese composite material is denoted as HNT@10CeMn.

[0033] Comparative Example 2

[0034] A method for preparing halloysite-supported cerium-manganese composite material, the steps of which are as described in Example 1;

[0035] The difference is that in step (1) of Comparative Example 2, 5% by mass of cerium material is added, and the halloysite-supported cerium-manganese composite material is denoted as HNT@5CeMn.

[0036] Using halloysite (HNT) as a blank control, the halloysite-supported cerium-manganese composite materials prepared in Example 1 and Comparative Example 1 were characterized by X-ray diffraction:

[0037] The halloysite-supported cerium-manganese composite material was thoroughly ground and then dried in an oven at 105°C for 4 hours to remove moisture. Characterization was performed using a Bruker D8 Advance X-ray diffractometer with a scan speed of 5° / min and an angle range of 5–70°. The XRD patterns are shown below. Figure 1 ;from Figure 1It can be seen that the decrease in reflection intensity after halloysite modification indicates that the synthesized composite material has low crystallinity. The presence of characteristic peaks indicates that the modification process did not destroy the crystal structure of halloysite.

[0038] Example 2

[0039] A method for preparing halloysite-supported cerium-manganese composite material, comprising the following steps:

[0040] (1) Add halloysite to deionized water and stir and disperse at room temperature for 20 min. Add cerium material (cerium nitrate hexahydrate) and potassium permanganate (cerium-manganese ratio of 3:1). Then add dilute sulfuric acid to adjust the pH of the solution to 1. The cerium material accounts for 20% of the mass fraction of halloysite.

[0041] (2) Heat to 80℃ and stir for 12 hours, then cool. After cooling, add sodium hydroxide solution dropwise to adjust the pH to 10.5.

[0042] (3) The solution in step (2) is separated into solid and liquid by vacuum filtration. During the vacuum filtration process, sufficient deionized water is added to wash until the filtrate is neutral, and residual sodium hydroxide and sulfate ions are washed away.

[0043] (4) The solid separated from the liquid is dried at 80°C for 6 hours and ground. The product obtained is halloysite-supported cerium-manganese composite material, denoted as HNT@20CeMn-1S.

[0044] Comparative Example 3

[0045] A method for preparing halloysite-supported cerium-manganese composite material, the steps of which are as described in Example 2;

[0046] The difference is that in step (1) of Comparative Example 3, the pH of the solution is adjusted to 2 with dilute sulfuric acid, and the halloysite-supported cerium-manganese composite material is denoted as HNT@20CeMn-2S.

[0047] Comparative Example 4

[0048] A method for preparing halloysite-supported cerium-manganese composite material, the steps of which are as described in Example 2;

[0049] The difference is that in step (1) of Comparative Example 4, the pH of the solution was adjusted to 1 with dilute nitric acid, and the halloysite-supported cerium-manganese composite material was denoted as HNT@20CeMn-1N.

[0050] Comparative Example 5

[0051] A method for preparing halloysite-supported cerium-manganese composite material, the steps of which are as described in Example 3;

[0052] The difference is that in step (1) of Comparative Example 5, cerium material (cerium nitrate hexahydrate) and potassium permanganate (cerium-manganese ratio of 4:1) are added, and the halloysite-supported cerium-manganese composite material is denoted as HNT@20CeMn4 / 1.

[0053] Comparative Example 6

[0054] A method for preparing halloysite-supported cerium-manganese composite material, the steps of which are as described in Example 3;

[0055] The difference is that in step (1) of Comparative Example 6, cerium material (cerium nitrate hexahydrate) and potassium permanganate (cerium-manganese ratio of 3:2) are added, and the halloysite-supported cerium-manganese composite material is denoted as HNT@20CeMn3 / 2.

[0056] The halloysite-supported cerium-manganese composite materials prepared in Examples 1-2 and Comparative Examples 1-6 were subjected to adsorption experiments for arsenic and antimony, as detailed below:

[0057] Prepare solutions of 10 mg / L trivalent arsenic (sodium arsenite), 10 mg / L pentavalent arsenic (sodium arsenate), 20 mg / L trivalent antimony (potassium antimony tartrate), and 20 mg / L pentavalent antimony (potassium antimony pyroantimonate); the pH of the above solutions is 3, and the pH is adjusted with sodium hydroxide solution and hydrochloric acid solution.

[0058] Add 20 mL of a 1.0 g / L solution, prepared from 20 mg halloysite-supported cerium-manganese composite material, to 20 mL of trivalent arsenic solution and trivalent antimony solution, respectively.

[0059] Add 20 mL of a 0.5 g / L solution prepared from 10 mg halloysite-supported cerium-manganese composite material to 20 mL of pentavalent arsenic solution and pentavalent antimony solution, respectively.

[0060] The mixed solution was placed in a water bath shaker and shaken at a shaking rate of 200 r / min and a temperature of 25°C. Removal rate tests were conducted during the experiment. The relationship between the contact time and removal rate of the composite material in Example 1 is as follows: Figure 2 After shaking for 8 hours, the solution was removed from the bottle using a medical syringe and then filtered through a disposable filter with a pore size of 0.22 μm. The concentration of arsenic and antimony in the filtered solution was determined using an ICP-OES spectrometer. The removal rate (%) after shaking for 8 hours is shown in Table 1.

[0061] Table 1

[0062]

[0063]

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing halloysite-supported cerium-manganese composite material, characterized in that, Includes the following steps: (1) Add halloysite powder to deionized water and stir and disperse at room temperature for 20 min. Add cerium material and potassium permanganate, and then add dilute sulfuric acid. (2) Heat to 80℃ and stir for 12 hours, then cool and add sodium hydroxide solution dropwise after cooling; (3) Perform solid-liquid separation on the solution in step (2); (4) The solid separated from the liquid is dried at 80°C for 6 hours or more and then ground to obtain the halloysite-supported cerium-manganese composite material. In step (1), the cerium material accounts for 20% or 25% of the mass fraction of halloysite, and the cerium material is cerium nitrate hexahydrate; the cerium material and potassium permanganate are added at a cerium-manganese molar ratio of 3:

1. Step (1) Add dilute sulfuric acid until the pH value is 1; Step (2) Add sodium hydroxide solution with a pH of 10.

5.

2. The method for preparing halloysite-supported cerium-manganese composite material according to claim 1, characterized in that, Step (3) Solid-liquid separation is achieved by vacuum filtration. During the vacuum filtration process, deionized water is added to wash until the filtrate is neutral.

3. A halloysite-supported cerium-manganese composite material, characterized in that, The composite material is prepared according to the method for preparing halloysite-supported cerium-manganese composite material according to any one of claims 1-2.

4. The application of the halloysite-supported cerium-manganese composite material according to claim 3, characterized in that, The halloysite-supported cerium-manganese composite material is used to adsorb arsenic and antimony in wastewater.

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