Magnetic adsorbent as well as preparation method and application thereof

Abstract

The invention provides a magnetic adsorbent as well as a preparation method and application thereof, and belongs to the technical field of water treatment. The preparation method of the magnetic adsorbent comprises the following steps: performing first mixing on a FeCl3 solution and a FeCl2 solution to obtain an iron source solution; adding an alkali solution into the ferric salt solution for secondary mixing to obtain magnetic particles; placing the magnetic particles in a surface modifier for third mixing to obtain modified magnetic particles; adding a NaOH solution into the micro-emulsion system containing CaSO4 for reaction to obtain porous calcium hydroxide; the modified magnetic particles, porous calcium hydroxide and ethyl alcohol are mixed and then subjected to ultrasonic treatment, and the magnetic adsorbent is obtained. The surface modifier is adopted to modify the magnetic particles, so that the magnetic particles have higher stability and can continuously and efficiently adsorb arsenic, meanwhile, the binding capacity of the magnetic particles and the arsenic is improved, and the magnetic particles have higher adsorption capacity and adsorption rate on the arsenic.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a magnetic adsorbent and a preparation method and application thereof. Background Art

[0002] Magnetic adsorbents are usually composed of magnetic particles and adsorbents, where the magnetic particles are the carriers of the adsorbents. These magnetic particles have high magnetic permeability and magnetic saturation, and can generate strong magnetic fields, thereby achieving adsorption and separation of substances.

[0003] The application fields of magnetic adsorbents include water treatment, environmental protection, biomedicine and food, among which magnetic adsorbents have broad application prospects in the field of water treatment. They can be used to remove heavy metal ions, organic pollutants and other harmful substances in water to improve the safety and cleanliness of water quality; in the field of environmental protection, magnetic adsorbents can be used to treat industrial wastewater and soil remediation. By adsorbing and removing pollutants in the environment, it helps to protect the ecological environment and human health; in the biomedical field, it can be used for targeted drug delivery, cell separation and purification, etc. Through the magnetic responsiveness of magnetic adsorbents, it can achieve the precise release of drugs at specific sites and the efficient separation of cells; in the food field, it can also be used to detect harmful substances.

[0004] Arsenic is a toxic element that is widely present in nature. In water bodies, arsenic mainly exists in the form of inorganic arsenic (trivalent arsenic and pentavalent arsenic) and organic arsenic. After arsenic enters the human body, it will interfere with the body's metabolic process. Long-term exposure to arsenic-containing sewage environment, drinking or contact with arsenic-containing sewage, will cause serious harm to human health. For example, it can cause skin lesions such as pigmentation, hyperkeratosis, and may even cause skin cancer. At the same time, arsenic can also have adverse effects on the human nervous system, cardiovascular system, and urinary system, leading to diseases such as peripheral neuropathy, arrhythmia, and renal damage.

[0005] Existing magnetic adsorbents generally have problems such as low adsorption capacity, low arsenic removal rate and difficulty in separation and recycling, which restricts the application of magnetic arsenic adsorbents.

[0006] Based on this, it is of great practical significance to provide a magnetic adsorbent with high adsorption capacity and high arsenic removal rate. Summary of the invention

[0007] The purpose of the present invention is to provide a magnetic adsorbent and a preparation method and application thereof, aiming to solve the technical problems of low adsorption capacity and low removal rate of magnetic adsorbent in the prior art.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0009] The present invention provides a method for preparing a magnetic adsorbent, comprising the following steps:

[0010] FeCl 3 Solution and FeCl 2 The solution is first mixed to obtain an iron source solution;

[0011] adding an alkaline solution to the iron source solution for a second mixing to obtain magnetic particles;

[0012] After washing the magnetic particles, placing them in a surface modifier for a third mixing to obtain modified magnetic particles;

[0013] Add NaOH solution to the CaSO 4 The reaction is carried out in a microemulsion system to obtain porous calcium hydroxide;

[0014] The modified magnetic particles, porous calcium hydroxide and ethanol are mixed and then ultrasonically treated to obtain the magnetic adsorbent.

[0015] Furthermore, the FeCl 3 Solution and FeCl 2 The concentrations of the solutions are 15-20 g / L and 6-12 g / L respectively.

[0016] Furthermore, the first mixture of FeCl 3 Solution and FeCl 2 The ratio of the solution is 2-4:1-2.

[0017] Further, the alkaline solution is NH 3 ·H 2 O.

[0018] Furthermore, the second mixed iron source solution and NH 3 ·H 2 The mass ratio of O is 4~7:2~4.

[0019] Furthermore, the surface modifier is isopropyl orthosilicate, the concentration of the surface modifier is 0.2-0.3M, and the mass ratio of the surface modifier to the magnetic particles in the third mixture is 3-4:1.

[0020] Furthermore, the usage ratio of the modified magnetic particles, porous calcium hydroxide and ethanol is 3-5:2-4:30-50 mL.

[0021] Furthermore, the microemulsion system is an aqueous solution of ethanol, and the volume ratio of ethanol to water in the microemulsion system is 3 to 4:1.

[0022] The present invention also provides a magnetic adsorbent obtained by the preparation method of the magnetic adsorbent described in the above technical solution.

[0023] The present invention also provides the use of the magnetic adsorbent described in the above technical solution in water treatment.

[0024] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0025] (1) The present invention uses FeCl 3 Solution and FeCl 2 The solution was used as an iron source to prepare magnetic adsorption particles, and the magnetic particles were modified by a surface modifier, isopropyl orthosilicate. After the isopropyl orthosilicate was hydrolyzed, a layer of network-like cross-linked SiO 2 , this layer of SiO 2 It can effectively organize the direct contact between magnetic particles, thereby reducing the interaction force between them and preventing particles from agglomerating. 2 As an inorganic protective layer, the layer can effectively prevent the magnetic particles from reacting with oxygen or other chemicals in the air, thereby improving their antioxidant properties and chemical stability, allowing their adsorption to proceed continuously and efficiently, and improving the adsorption capacity and adsorption rate of the magnetic particles.

[0026] (2) The present invention uses porous calcium hydroxide as a carrier of magnetic particles. Porous calcium hydroxide has a higher specific surface area and a richer pore structure, which can provide more loading sites for the modified magnetic particles, thereby improving the adsorption capacity and adsorption rate of the magnetic particles. DETAILED DESCRIPTION

[0027] The application fields of magnetic adsorbents include water treatment, environmental protection, biomedicine and food, among which magnetic adsorbents have broad application prospects in the field of water treatment. They can be used to remove heavy metal ions, organic pollutants and other harmful substances in water to improve the safety and cleanliness of water quality; in the field of environmental protection, magnetic adsorbents can be used to treat industrial wastewater and soil remediation. By adsorbing and removing pollutants in the environment, it helps to protect the ecological environment and human health; in the biomedical field, it can be used for targeted drug delivery, cell separation and purification, etc. Through the magnetic responsiveness of magnetic adsorbents, it can achieve the precise release of drugs at specific sites and the efficient separation of cells; in the food field, it can also be used to detect harmful substances.

[0028] Arsenic is a toxic element that is widely present in nature. In water bodies, arsenic mainly exists in the form of inorganic arsenic (trivalent arsenic and pentavalent arsenic) and organic arsenic. After arsenic enters the human body, it will interfere with the body's metabolic process. Long-term exposure to arsenic-containing sewage environment, drinking or contact with arsenic-containing sewage, will cause serious harm to human health. For example, it can cause skin lesions such as pigmentation, hyperkeratosis, and may even cause skin cancer. At the same time, arsenic can also have adverse effects on the human nervous system, cardiovascular system, and urinary system, leading to diseases such as peripheral neuropathy, arrhythmia, and renal damage.

[0029] Existing magnetic adsorbents generally have problems such as low adsorption capacity, low arsenic removal rate and difficulty in separation and recycling, which restricts the application of magnetic arsenic adsorbents. Based on the above background:

[0030] The present invention provides a method for preparing a magnetic adsorbent, comprising the following steps:

[0031] FeCl 3 Solution and FeCl 2 The solution is first mixed to obtain an iron source solution;

[0032] adding an alkaline solution to the iron source solution for a second mixing to obtain magnetic particles;

[0033] After washing the magnetic particles, placing them in a surface modifier for a third mixing to obtain modified magnetic particles;

[0034] Add NaOH solution to the CaSO 4 The reaction is carried out in a microemulsion system to obtain porous calcium hydroxide;

[0035] The modified magnetic particles, porous calcium hydroxide and ethanol are mixed and then ultrasonically treated to obtain the magnetic adsorbent.

[0036] In the present invention, the FeCl 3 Solution and FeCl 2 The concentration of the solution is preferably 15 to 20 g / L and 6 to 12 g / L, and more preferably 15 to 18 g / L and 6 to 9 g / L, respectively.

[0037] In the present invention, the first mixed FeCl 3 Solution and FeCl 2 The ratio of the solution is preferably 2-4:1-2.

[0038] adding an alkaline solution to the iron source solution for a second mixing to obtain magnetic particles;

[0039] The present invention mixes an iron source solution with an alkaline solution, stirs them evenly, filters them, and washes the obtained magnetic particles until they are neutral to obtain the magnetic particles to be used.

[0040] In the present invention, the alkaline solution is preferably NH 3 ·H 2 O.

[0041] In the present invention, the second mixed iron source solution and NH 3 ·H 2 The mass ratio of O is preferably 4 to 7:2 to 4, and more preferably 4 to 5:2 to 3.

[0042] After washing the magnetic particles, placing them in a surface modifier for a third mixing to obtain modified magnetic particles;

[0043] After the magnetic particles are washed, the magnetic particles to be used are placed in a surface modifier for mixing. The third mixing is preferably carried out by ultrasonic treatment. After 30 minutes of ultrasonic treatment, surface-modified magnetic particles are obtained. The present invention does not specifically limit the parameters of the ultrasonic treatment, and the parameters that can attach the surface modifier to the surface of the magnetic particles can be used.

[0044] In the present invention, the surface modifier is preferably isopropyl orthosilicate, and the concentration of the surface modifier is preferably 0.2-0.3M, more preferably 0.2M; the mass ratio of the surface modifier to the magnetic particles in the third mixing is preferably 3-4:1, more preferably 3:1.

[0045] The present invention adopts FeCl 3 Solution and FeCl 2 The solution was used as an iron source to prepare magnetic adsorption particles, and the magnetic particles were modified by a surface modifier, isopropyl orthosilicate. After the isopropyl orthosilicate was hydrolyzed, a layer of network-like cross-linked SiO 2 , this layer of SiO 2 It can effectively organize the direct contact between magnetic particles, thereby reducing the interaction force between them and preventing particles from agglomerating. 2 As an inorganic protective layer, the layer can effectively prevent the magnetic particles from reacting with oxygen or other chemicals in the air, thereby improving their antioxidant properties and chemical stability, allowing their adsorption to proceed continuously and efficiently, and improving the adsorption capacity and adsorption rate of the magnetic particles.

[0046] Add NaOH solution to the CaSO 4 The reaction is carried out in a microemulsion system to obtain porous calcium hydroxide;

[0047] In the present invention, the microemulsion system is an aqueous solution of ethanol, and the volume ratio of ethanol to water in the microemulsion system is preferably 3 to 4:1, and more preferably 3 to 3.5:1.

[0048] The present invention adopts NaOH solution and CaSO 4 The porous calcium hydroxide prepared by the present invention has a higher specific surface area and a rich void structure, which can provide more loading sites for the magnetic particles prepared by the present invention, thereby further improving the adsorption capacity and adsorption rate of the magnetic particles for arsenic in water.

[0049] The NaOH and CaSO 4 The molar ratio of is preferably 2 to 3:1, more preferably 2:1.

[0050] The modified magnetic particles, porous calcium hydroxide and ethanol are mixed and then ultrasonically treated to obtain the magnetic adsorbent.

[0051] In the present invention, the usage ratio of the modified magnetic particles, porous calcium hydroxide and ethanol is preferably 3-5 g:2-4 g:30-50 mL, and more preferably 3 g:2 g:30 mL.

[0052] The invention places the modified magnetic particles and porous calcium hydroxide in ethanol for mixing, and then performs ultrasonic treatment, so that the modified magnetic particles are loaded on the porous calcium hydroxide.

[0053] The present invention adopts ultrasonic treatment to load the modified magnetic particles on the porous calcium hydroxide. The present invention does not specifically limit the parameters of the ultrasonic treatment. The embodiment of the present invention preferably limits the time of the ultrasonic treatment to 30 minutes.

[0054] The present invention also provides a magnetic adsorbent obtained by the preparation method of the magnetic adsorbent described in the above technical solution.

[0055] The present invention also provides the use of the magnetic adsorbent described in the above technical solution in water treatment.

[0056] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0057] Example 1

[0058] (1) Add 15 g / L FeCl 3 solution and FeCl with a concentration of 6 g / L 2 The solutions are mixed and stirred to obtain an iron source solution;

[0059] (2) The obtained iron source solution was mixed with NH3 ·H 2 O are mixed in a mass ratio of 2:1, and after being stirred evenly, a precipitate is obtained, and the obtained precipitate is washed with pure water until it is neutral to obtain magnetic particles;

[0060] (3) After the magnetic particles are cleaned, the magnetic particles are mixed with 0.2 M isopropyl orthosilicate in a ratio of 3:1, stirred evenly, and allowed to stand to obtain modified magnetic particles;

[0061] (4) Ethanol: water was mixed in a ratio of 3:1 to obtain a microemulsion system, and then CaSO 4 , making CaSO 4 The concentration is 0.5M, and then an equal amount of 1M NaOH solution is added to make the NaOH and CaSO 4 The molar ratio of the mixture is 2:1. After being evenly mixed, the mixture is allowed to stand. Finally, the porous calcium hydroxide is washed until there is no impurity on the surface and then used for later use.

[0062] (5) The modified magnetic particles, porous calcium hydroxide and ethanol were mixed in a dosage ratio of 3 g:2 g:30 mL, and after mixing evenly, ultrasonic treatment was performed for 30 minutes, and the mixture was allowed to stand and then washed to obtain the magnetic adsorbent.

[0063] Example 2

[0064] (1) Add 18 g / L FeCl 3 solution and FeCl with a concentration of 9 g / L 2 The solutions are mixed and stirred to obtain an iron source solution;

[0065] (2) The obtained iron source solution was mixed with NH 3 ·H 2 O are mixed in a mass ratio of 1:1, and after being stirred evenly, a precipitate is obtained, and the obtained precipitate is washed with pure water until it is neutral to obtain magnetic particles;

[0066] (3) After the magnetic particles are cleaned, the magnetic particles are mixed with 0.3 M isopropyl orthosilicate in a ratio of 4:1, stirred evenly, and allowed to stand to obtain modified magnetic particles;

[0067] (4) Ethanol: water was mixed in a ratio of 3.5:1 to obtain a microemulsion system, and then CaSO 4 , making CaSO 4 The concentration is 0.5M, and then an equal amount of 1M NaOH solution is added to make the NaOH and CaSO 4The molar ratio of the mixture is 2:1, and after being evenly mixed, the mixture is allowed to stand, and finally the porous calcium hydroxide is washed until there is no impurity on the surface and then used for later use;

[0068] (5) The modified magnetic particles, porous calcium hydroxide and ethanol were mixed in a dosage ratio of 5 g:4 g:50 mL, and after mixing evenly, ultrasonic treatment was performed for 30 minutes, and the mixture was allowed to stand and then washed to obtain the magnetic adsorbent.

[0069] Example 3

[0070] (1) Add 20 g / L FeCl 3 solution and FeCl with a concentration of 12 g / L 2 The solutions are mixed and stirred to obtain an iron source solution;

[0071] (2) The obtained iron source solution was mixed with NH 3 ·H 2 O are mixed in a mass ratio of 4:3, and after being stirred evenly, a precipitate is obtained, and the obtained precipitate is washed with pure water until it is neutral to obtain magnetic particles;

[0072] (3) After the magnetic particles are cleaned, the magnetic particles are mixed with 0.2 M isopropyl orthosilicate in a ratio of 4:1, stirred evenly, and allowed to stand to obtain modified magnetic particles;

[0073] (4) Ethanol: water was mixed in a ratio of 4:1 to obtain a microemulsion system, and then CaSO 4 , making CaSO 4 The concentration is 0.4M, and then an equal amount of 1.2M NaOH solution is added to make the NaOH and CaSO 4 The molar ratio of the mixture is 3:1. After being evenly mixed, the mixture is allowed to stand. Finally, the porous calcium hydroxide is washed until there is no impurity on the surface and then used for later use.

[0074] (5) The modified magnetic particles, porous calcium hydroxide and ethanol were mixed in a dosage ratio of 3 g:4 g:30 mL, and after mixing evenly, ultrasonic treatment was performed for 30 minutes, and the mixture was allowed to stand and then washed to obtain the magnetic adsorbent.

[0075] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a magnetic adsorbent, characterized in that: The following steps are involved: The FeCl3 solution and the FeCl2 solution are first mixed to obtain an iron source solution; adding an alkaline solution to the iron source solution for a second mixing to obtain magnetic particles; After washing the magnetic particles, placing them in a surface modifier for a third mixing to obtain modified magnetic particles; The NaOH solution is added into the microemulsion system containing CaSO4 to react and obtain porous calcium hydroxide; The modified magnetic particles, porous calcium hydroxide and ethanol are mixed and then ultrasonically treated to obtain the magnetic adsorbent.

2. The method for preparing a magnetic adsorbent according to claim 1, characterized in that: The concentrations of the FeCl3 solution and the FeCl2 solution are 15-20 g / L and 6-12 g / L respectively.

3. The method for preparing a magnetic adsorbent according to claim 1, characterized in that: The ratio of the FeCl3 solution to the FeCl2 solution in the first mixture is 2-4:1-2.

4. The method for preparing a magnetic adsorbent according to claim 1, characterized in that: The alkaline solution is NH3·H2O.

5. The method for preparing a magnetic adsorbent according to claim 4, characterized in that: The mass ratio of the iron source solution to NH3·H2O in the second mixture is 4-7:2-4.

6. The method for preparing a magnetic adsorbent according to claim 1, characterized in that: The surface modifier is isopropyl orthosilicate, the concentration of the surface modifier is 0.2-0.3M, and the mass ratio of the surface modifier to the magnetic particles in the third mixture is 3-4:

1.

7. The method for preparing a magnetic adsorbent according to claim 1, characterized in that: The usage ratio of the modified magnetic particles, porous calcium hydroxide and ethanol is 3-5:2-4:30-50 mL.

8. The method for preparing a magnetic adsorbent according to claim 1, characterized in that: The microemulsion system is an aqueous solution of ethanol, and the volume ratio of ethanol to water in the microemulsion system is 3-4:

1.

9. A magnetic adsorbent obtained by the preparation method of the magnetic adsorbent according to any one of claims 1 to 8.

10. Use of the magnetic adsorbent according to claim 9 in water treatment.