Functionalized nano particle and preparation method and application thereof

Abstract

The invention relates to the field of water treatment, and discloses a functionalized nanoparticle as well as a preparation method and application thereof. The nanoparticle has a core-shell structure, the shell is an aromatic amine polymer, and the core is a magnetic nanoparticle; wherein on the basis of the total weight of the functionalized nanoparticles, the mass percentage of the element N is 2-20 wt%. The functionalized magnetic nanoparticles take nanoparticles as cores and aromatic amine polymers as shells, so that the surfaces of the functionalized nanoparticles are enriched with N elements, which indicates that the surfaces of the nanoparticles contain a large number of N-containing functional groups, so that the functionalized nanoparticles have a large specific surface area, and the adsorption capacity of the nanoparticles to heavy metal ions is improved; heavy metal ions in water can be effectively adsorbed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of water treatment, in particular, to a functionalized nanoparticle and a preparation method and application thereof. BACKGROUND

[0002] Heavy metal pollution (lead, cadmium, mercury, chromium, copper, cobalt, nickel, etc.) in water bodies is a serious problem in the world's environmental governance. A large number of toxic heavy metal ions accumulate in water and are difficult to degrade, ultimately posing a serious threat to human health and the environment. Among the currently commonly used heavy metal ion removal methods (including chemical precipitation, ion exchange, electrochemistry, membrane separation, adsorption, biochemical separation), adsorption method is widely concerned for its easy operation, high efficiency in removing trace heavy metals, low cost, high selectivity and other advantages (J. Colloid Interface Sci. 2016, 462, 235-242). Natural minerals, carbon materials, and artificially synthesized nanoparticles are all commonly used adsorbent materials, but these adsorbent materials generally have the disadvantages of difficulty in separation and recovery, low adsorption capacity, and poor adsorption selectivity. Functionalized magnetic adsorbent materials have high adsorption capacity, are easy to separate and recycle, and are low in cost, and have outstanding advantages and important research value in heavy metal ion adsorption and detection (Ecotoxicol. Environ. Saf. 2018, 147, 699-707).

[0003] Although there are many ways to modify magnetic nano-adsorbents, such as using silane coupling agents or modifying functional groups (such as thiol, hydroxyl, carboxyl, etc.), most studies use small molecule functional groups for modification, which results in low surface active group binding rate, poor structural stability, poor adsorption capacity for heavy metal ions, and low adsorption capacity and adsorption efficiency.

[0004] CN112108128A discloses a hydrophilic hyperbranched polyglycidol ether anion magnetic adsorbent, which has good structural stability, strong magnetic response, and high reusability, but its preparation process is complicated and the adsorption type is single.

[0005] CN113634221A discloses an Al2O3 modified Fe3O4 magnetic nanomaterial, which is coated with a cationic modifier, has mild synthesis reaction conditions, and can adsorb anionic dyes through electrostatic interaction, but has small adsorption capacity and low reusability efficiency.

[0006] CN109317117A discloses a core-shell structure magnetic composite microsphere combining polydopamine organic ligand and magnetic nanomaterial, which can adsorb actinides in a weakly acidic environment, has fast separation speed, and is easy to recycle. However, it has small adsorption capacity and poor structural stability. SUMMARY

[0007] The present application aims to overcome the problems of poor adsorption of heavy metal ions and poor separation and recovery of adsorbents in the prior art, and provides functionalized nanoparticles, a preparation method and application thereof. The functionalized nanoparticles have a core-shell structure, wherein the shell is an aromatic amine polymer, and the core is a nanoparticle. The functionalized nanoparticles have a large specific surface area and high adsorption capacity for heavy metal ions, and can effectively adsorb heavy metal ions in water.

[0008] To achieve the above-mentioned purpose, the present application provides a functionalized nanoparticle, wherein the nanoparticle has a core-shell structure, wherein the shell is an aromatic amine polymer, and the core is a nanoparticle.

[0009] The mass percentage of N element is 2-20wt% based on the total weight of the functionalized nanoparticles.

[0010] The present application provides a preparation method of a functionalized nanoparticle, wherein the preparation method comprises the following steps:

[0011] S1, mixing the nanoparticle with a solution containing a modifier to obtain a mixture I;

[0012] S2, mixing the mixture I, an aromatic amine monomer, an initiator and an acid dopant, and then performing a polymerization reaction to obtain a mixture II;

[0013] S3, washing and drying the mixture II to obtain the functionalized nanoparticle;

[0014] The modifier is selected from at least one of polyethylene glycol, sodium hexadecyl benzene sulfonate, sodium dodecyl sulfate and sodium lignosulfonate.

[0015] The present application provides a functionalized nanoparticle prepared by the above preparation method.

[0016] The present application provides a functionalized nanoparticle prepared by the above preparation method.

[0017] The functionalized nanoparticles, the preparation method and the application thereof provided by the present application have the following beneficial effects:

[0018] The functionalized nanoparticles provided by the application are core-shell structures, the core is nanoparticles, and the shell is aromatic amine polymer. The aromatic amine polymer as the shell makes the surface of the functionalized nanoparticles rich in N elements, and the functionalized nanoparticles have a large number of N-containing functional groups on the surface, so that the aromatic amine polymer on the surface of the functionalized nanoparticles is modified, and the functionalized nanoparticles have high adsorption capacity for heavy metal ions. When the functionalized nanoparticles are used for sewage treatment, the adsorption rate of the heavy metal ions is 50% or more.

[0019] Further, the shell layer of the functionalized nanoparticles provided by the application has a large thickness and a large specific surface area. The aromatic amine polymer forming the shell is radially distributed, which can not only ensure that the active sites for adsorbing metal ions are exposed on the surface of the functionalized nanoparticles and fully contact the metal ions, but also further improve the adsorption effect of the functionalized nanoparticles on the heavy metal ions.

[0020] Further, the functionalized nanoparticles provided by the application have strong magnetism, which is convenient for magnetic separation and recovery, and improves the secondary pollution problem existing in some adsorbents.

[0021] The preparation method of the functionalized nanoparticles provided by the application has mild reaction conditions and simple steps, and the prepared functionalized nanoparticles do not agglomerate after long-term storage, and have good stability. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a scanning electron microscope (SEM) photo of the ferroferric oxide (Fe3O4) nanoparticles of Preparation Example 1 of the application.

[0023] Figure 2 It is a scanning electron microscope (SEM) photo of the functionalized magnetic nanoparticles of Example 2 of the application. DETAILED DESCRIPTION

[0024] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The exact numerical values of the endpoints of the ranges and the separate values are not to be construed as being precise values, and they are understood to be used in a merely illustrative sense. Within the scope of this disclosure, any value can be used as a replacement for a value disclosed herein.

[0025] The first aspect of the application provides a functionalized nanoparticle, wherein the functionalized nanoparticle has a core-shell structure, wherein the shell is an aromatic amine polymer, and the core is a nanoparticle.

[0026] The mass percentage of N element is 2-20 wt% based on the total weight of the functionalized magnetic nanoparticles.

[0027] In this invention, the functionalized magnetic nanoparticles have a magnetic nanoparticle core and an aromatic amine polymer as a shell. The aromatic amine polymer as a shell enriches the surface of the functionalized nanoparticles with nitrogen, indicating that the nanoparticles contain a large number of nitrogen-containing functional groups and have a high adsorption capacity for heavy metal ions. When used for wastewater treatment, they can adsorb a large number of heavy metal ions.

[0028] In this invention, such as Figure 2 As shown, the shell of the functionalized nanoparticles provided by the present invention has a loose structure, and the aromatic amine polymer forming the shell is distributed in a fluffy manner. The inventors have found that the functionalized nanoparticles with the above-mentioned special structure can not only ensure that a large number of active groups are exposed on the surface of the functionalized nanoparticles, but also significantly increase the specific surface area of ​​the functionalized nanoparticles, thereby further improving the adsorption effect of the functionalized nanoparticles on heavy metal ions.

[0029] Furthermore, in this invention, the shell formed by the aromatic amine polymer allows the surface of the nanoparticles to contain a specific amount of nitrogen element, which can improve the binding ability of the nanoparticles to heavy metal ions. When used in wastewater treatment, it can enhance the adsorption capacity of heavy metal ions in wastewater.

[0030] In this invention, the N-containing functional group refers to amino and / or imino groups.

[0031] Furthermore, based on the total weight of the functionalized nanoparticles, the mass percentage of nitrogen is 4-16 wt%.

[0032] According to the present invention, the specific surface area of ​​the functionalized nanoparticles is 40-200 m². 2 / g.

[0033] In this invention, when the specific surface area of ​​the functionalized nanoparticles meets the above-mentioned range, the nanoparticles have a high specific surface area and a high nitrogen content, which can further improve the adsorption effect of the functionalized nanoparticles on heavy metal ions.

[0034] Furthermore, the specific surface area of ​​the functionalized nanoparticles is 60-160 m². 2 / g.

[0035] According to the present invention, the average particle size of the functionalized nanoparticles is 50-300 nm.

[0036] In this invention, when the average particle size of the functionalized nanoparticles meets the above-mentioned range, the nanoparticles are not prone to agglomeration and have good dispersibility.

[0037] Furthermore, the average particle size of the functionalized nanoparticles is 60-230 nm.

[0038] According to the present invention, the average thickness of the shell is 10-100 nm.

[0039] In this invention, when the thickness of the shell meets the above-mentioned range, it can increase the specific surface area of ​​the nanoparticles while the surface of the functional nanoparticles contains a high amount of nitrogen, thereby further improving the adsorption capacity of the nanoparticles for heavy metals.

[0040] Furthermore, the average thickness of the shell is 20-80 nm.

[0041] According to the present invention, the aromatic amine polymer is selected from at least one of polyaniline, poly(o-phenylene diamine), poly(m-phenylene diamine), and poly(p-phenylene diamine).

[0042] In this invention, preferably, the nanoparticles are magnetic nanoparticles, which can utilize the magnetism of the nanoparticles to achieve the separation of functionalized nanoparticles.

[0043] According to the present invention, the nanoparticles are selected from at least one of iron oxide, cobalt oxide, iron oxide and manganese oxide.

[0044] According to the present invention, the average particle size of the nanoparticles is 40-200 nm.

[0045] The second aspect of this invention provides a method for preparing functionalized nanoparticles, wherein the preparation method includes the following steps:

[0046] S1. The magnetic nanoparticles are first mixed with a solution containing a modifier to obtain mixture I;

[0047] S2. After mixing mixture I, aromatic amine monomer, initiator and acid dopant in a second mixture, a polymerization reaction is carried out to obtain mixture II;

[0048] S3. After washing and drying mixture II, the functionalized nanoparticles are obtained;

[0049] The modifier is selected from at least one of polyethylene glycol, sodium hexadecylbenzenesulfonate, sodium dodecyl sulfate, and sodium lignosulfonate.

[0050] In this invention, nanoparticles are mixed with a solution containing a modifier, and then an acid dopant and an initiator are added to polymerize aromatic amine monomers onto the surface of the nanoparticles, thereby forming the functionalized nanoparticles with a core-shell structure as described in this invention. This preparation method has mild reaction conditions, simple steps, a large specific surface area of ​​the product, a thicker shell, and good product stability.

[0051] Furthermore, in this invention, the use of the aforementioned specific type of modifier can increase the specific surface area of ​​the functionalized nanoparticles, thereby improving the adsorption capacity of the functionalized nanoparticles for heavy metals.

[0052] Furthermore, the modifier is selected from at least one of polyethylene glycol, sodium dodecyl sulfate, and sodium lignosulfonate.

[0053] According to the present invention, the mass ratio of the modifier to the magnetic nanoparticles is 0.1-1:1.

[0054] In this invention, when the mass ratio of the modifier to the magnetic nanoparticles is controlled to meet the above-mentioned range, the nitrogen content on the surface of the functionalized nanoparticles can be increased, thereby improving the adsorption capacity of the functionalized nanoparticles for heavy metals.

[0055] Furthermore, the mass ratio of the modifier to the magnetic nanoparticles is 0.3-0.8:1.

[0056] In this invention, the solution containing the modifier refers to an aqueous solution of the modifier. There are no special requirements for the solution containing the modifier, as long as the modifier can be fully dispersed in the water. For example, the mass-volume ratio of the modifier to water in the solution containing the modifier is 0.1-0.8 g / mL.

[0057] In this invention, the nanoparticles are selected from at least one of iron oxide, cobalt oxide, iron oxide and manganese oxide, preferably iron oxide.

[0058] In this invention, there are no particular limitations on the source of the nanoparticles; they can be purchased commercially or made in-house.

[0059] In one specific embodiment of the present invention, the nanoparticles are iron(III) oxide, which are prepared according to the following steps:

[0060] FeCl3·6H2O and FeCl2·4H2O were dissolved in ethylene glycol, and the pH was adjusted to 8-10 with an alkaline solution. Then, sodium citrate and oleic acid were added, and the mixture was shaken for 5-20 minutes. The reaction product was then placed in a high-pressure reactor and reacted in a forced-air oven at 150-200℃ for 5-10 hours. After cooling at room temperature, ferric oxide was obtained.

[0061] In this invention, the mass ratio of FeCl3·6H2O to FeCl2·4H2O is 0.8-3:1, preferably 1-2.5:1. In this invention, the amount of ethylene glycol used is 20-50 mL, preferably 30-40 mL.

[0062] In this invention, the alkaline solution is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

[0063] In this invention, sodium citrate (Na3C6H5O7·2H2O) is used as a reducing agent, and the amount of sodium citrate used is 10-23 wt% relative to the total mass of FeCl3·6H2O and FeCl2·4H2O.

[0064] In this invention, oleic acid is used as a surfactant to regulate the size distribution and morphology of iron(III) oxide. Relative to the total mass of FeCl3·6H2O and FeCl2·4H2O, oleic acid (C... 17 H 33 The amount of COOH used is 15-40 wt%.

[0065] In this invention, the temperature range of the forced-air drying oven is 160-180℃.

[0066] According to the present invention, the mass ratio of the nanoparticles to the aromatic amine monomer is 0.2-3:1.

[0067] In this invention, controlling the mass ratio of nanoparticles to aromatic amine monomers to meet the above-mentioned range can increase the nitrogen content on the surface of functionalized nanoparticles, thereby improving the adsorption capacity of functionalized nanoparticles for heavy metals.

[0068] Furthermore, the mass ratio of the nanoparticles to the aromatic amine monomer is 0.8-2:1.

[0069] According to the present invention, the aromatic amine monomer is selected from at least one of aniline, o-phenylenediamine, m-phenylenediamine and p-phenylenediamine.

[0070] According to the present invention, the mass ratio of the acid dopant to the aromatic amine monomer is 0.05-0.5:1.

[0071] In this invention, controlling the mass ratio of acid dopant to aromatic amine monomer to meet the above-mentioned range can improve the specific surface area and surface nitrogen content of functionalized nanoparticles, thereby improving the adsorption capacity of functionalized nanoparticles for heavy metals.

[0072] Furthermore, the mass ratio of the acid dopant to the aromatic amine monomer is 0.1-0.5:1.

[0073] According to the present invention, the acid dopant is selected from at least one of citric acid, acetic acid, phosphoric acid and sulfuric acid.

[0074] According to the present invention, the mass ratio of the initiator to the aromatic amine monomer is 0.05-0.5:1.

[0075] In this invention, controlling the mass ratio of the initiator to the aromatic amine monomer to meet the above-mentioned range can increase the specific surface area and the nitrogen content on the surface of the functionalized nanoparticles, thereby improving the adsorption capacity of the functionalized nanoparticles for heavy metals.

[0076] Furthermore, the mass ratio of the initiator to the aromatic amine monomer is 0.1-0.3:1.

[0077] According to the present invention, the initiator is selected from peroxide initiators, preferably at least one of ammonium persulfate, potassium persulfate and hydrogen peroxide.

[0078] According to the present invention, the first mixing is performed under ultrasonic conditions.

[0079] In this invention, the first mixing under ultrasonic conditions enables the nanoparticles to be fully and uniformly mixed with the solution containing the modifier, making it easier for the aromatic amine monomer to undergo polymerization on the surface of the nanoparticles, thereby increasing the nitrogen content on the surface of the functionalized nanoparticles.

[0080] According to the present invention, the conditions for the first mixing include: mixing temperature of 20-30°C, mixing time of 5-20 minutes, and ultrasonic power of 10-50W.

[0081] In this invention, the first mixing under the above conditions can further promote the polymerization reaction of aromatic amine monomers on the surface of nanoparticles, thereby increasing the nitrogen content on the surface of functionalized nanoparticles.

[0082] Furthermore, the conditions for the first mixing include: mixing temperature of 25-30°C, mixing time of 10-20 minutes, and ultrasonic power of 20-50W.

[0083] According to the present invention, the conditions for the polymerization reaction include: a polymerization temperature of 10-30°C and a polymerization time of 1-4 hours.

[0084] In this invention, carrying out the polymerization reaction under the specific conditions described above allows the polymerization reaction to proceed fully, thereby increasing the nitrogen content on the surface of the obtained functionalized nanoparticles.

[0085] Furthermore, the conditions for the polymerization reaction include: a polymerization temperature of 10-25°C and a polymerization time of 2-4 hours.

[0086] In this invention, the preparation method further includes washing the functionalized magnetic nanoparticles.

[0087] According to the present invention, the solvent used for washing is selected from ethanol and / or deionized water.

[0088] In one specific embodiment of the present invention, the washing is performed according to the following steps: the functionalized magnetic nanoparticles are washed 3-5 times alternately with ethanol and deionized water, and then dispersed in 30-60 ml of deionized water for later use.

[0089] According to the present invention, the drying is constant temperature vacuum drying or forced air drying.

[0090] A third aspect of the present invention provides functionalized magnetic nanoparticles prepared by the above-described preparation method.

[0091] The fourth aspect of this invention provides the application of functionalized magnetic nanoparticles in the adsorption of heavy metal ions.

[0092] The present invention will be described in detail below through embodiments.

[0093] The following examples,

[0094] The nitrogen content of the magnetic nanoparticles was determined by EDS energy dispersive spectroscopy analysis.

[0095] The specific surface area parameters of magnetic nano-ions were determined by a specific surface area and porosity analyzer (BET).

[0096] The surface morphology of magnetic nano-ions was determined by scanning electron microscopy.

[0097] The surface coating thickness and particle size of magnetic nano-ions were calculated using transmission electron microscopy.

[0098] The residual concentration of heavy metal ions after adsorption was determined by inductively coupled plasma spectroscopy.

[0099] The drugs and raw materials used in the experiment were all commercially available products, and there were no special processing requirements.

[0100] The following preparation examples illustrate the synthesis of Fe3O4 magnetic nanoparticles.

[0101] Preparation Example

[0102] 3g of FeCl3·6H2O and 2g of FeCl2·4H2O were dissolved in 30 mL of ethylene glycol, and then NaOH solution was added to adjust the pH to 9.5. Then, 0.75g of sodium citrate and 1g of oleic acid were added separately to the suspension, and the mixture was shaken for 10 minutes. The reaction solution was then placed in a 50 mL high-pressure reactor, and the reactor was transferred to a 160°C forced-air oven for 6 hours. After cooling at room temperature, iron(III) oxide nanoparticles were obtained. The product was washed repeatedly with deionized water and ethanol approximately 5-7 times, and then dried in a 60°C vacuum oven for 3 hours to obtain black, magnetic iron(III) oxide nanoparticles with an average particle size of 70 nm.

[0103] Example 1

[0104] S1. Take 6g of Fe3O4 magnetic nanoparticles and disperse them in 60mL of deionized water containing 4g of polyethylene glycol as a modifier. The mass ratio of the modifier to the magnetic carrier is 0.67:1. After mixing evenly, sonicate at 30℃ and 30W ultrasonic power for 30 minutes. Then, separate the solid by magnetic adsorption and record it as product 1.

[0105] S2. Product 1 was added to 50g of deionized water, followed by 5g of o-phenylenediamine, 2g of hydrochloric acid, and 1g of ammonium persulfate. The mixture was shaken for 5 minutes to mix thoroughly, and then placed in a 20°C constant temperature water bath for 3 hours. Product 2 was obtained by magnetic adsorption separation. The mass ratios of the magnetic carrier to o-phenylenediamine monomer were 1.2:1, the acid dopant to o-phenylenediamine monomer was 0.4:1, and the initiator to o-phenylenediamine monomer was 0.2:1.

[0106] S3. Wash product 2 three times with deionized water and dry it in a vacuum drying oven at 50°C for 6 hours to obtain functionalized magnetic nanoparticles A1.

[0107] Example 2

[0108] Referring to Example 1, the difference is:

[0109] S1: Disperse 10g of Fe3O4 magnetic nanoparticles in 60mL of deionized water containing 4g of polyethylene glycol as a modifier. The mass ratio of modifier to magnetic nanoparticles is 0.4:1.

[0110] S2: 1.5g of ammonium persulfate was added during the reaction. Based on the mass ratio, the ratio of magnetic nanoparticles to o-phenylenediamine monomer was 2:1, the ratio of acid dopant to o-phenylenediamine monomer was 0.4:1, and the ratio of initiator to o-phenylenediamine monomer was 0.3:1.

[0111] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles A2.

[0112] Example 3

[0113] Referring to Example 1, the difference is:

[0114] S2: Add product 1 to 50g of deionized water, then add 5g of o-phenylenediamine, 2.8g of hydrochloric acid, and 1g of ammonium persulfate sequentially. The mass ratios of magnetic nanoparticles to o-phenylenediamine are 1.2:1, the acid dopant to o-phenylenediamine is 0.56:1, and the initiator to o-phenylenediamine is 0.2:1.

[0115] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles A3.

[0116] Example 4

[0117] Referring to Example 1, the difference is:

[0118] S1: Disperse 6g of Fe3O4 magnetic nanoparticles in 60mL of deionized water containing 1.5g of polyethylene glycol as a modifier. The mass ratio of modifier to magnetic nanoparticles is 0.25:1. Other steps are the same as in Example 1, yielding product 1.

[0119] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles A4.

[0120] Example 5

[0121] Referring to Example 1, the difference is:

[0122] S1: Take 6g of Fe3O4 magnetic nanoparticles and disperse them in 60mL of deionized water containing 1.8g of modifier sodium lignosulfonate. The mass ratio of modifier to magnetic nanoparticles is 0.3:1.

[0123] S2: 2.5g of hydrochloric acid was added during the reaction. Based on the mass ratio, the ratio of magnetic nanoparticles to o-phenylenediamine monomer was 1.2:1, the ratio of acid dopant to o-phenylenediamine monomer was 0.5:1, and the ratio of initiator to o-phenylenediamine monomer was 0.2:1.

[0124] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles A5.

[0125] Example 6

[0126] Referring to Example 1, the difference is:

[0127] Step S2: Add product 1 to 50g of deionized water, then add 5g of o-phenylenediamine, 0.4g of hydrochloric acid, and 1g of potassium persulfate sequentially. The mass ratios of magnetic nanoparticles to o-phenylenediamine are 1.2:1, the acid dopant to o-phenylenediamine is 0.08:1, and the initiator to o-phenylenediamine is 0.2:1.

[0128] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles A6.

[0129] Example 7

[0130] Referring to Example 1, the difference is:

[0131] S2: Add product 1 to 50g of deionized water, then add 2.5g of aniline, 0.1g of hydrochloric acid, and 1g of potassium persulfate sequentially. The mass ratios of magnetic nanoparticles to aniline are 2.4:1, acid dopant to aniline are 0.04:1, and initiator to aniline are 0.4:1.

[0132] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles A7.

[0133] Example 8

[0134] Referring to Example 1, the difference is:

[0135] S1. Take 6g of Fe3O4 magnetic nanoparticles and disperse them in 60mL of deionized water containing 0.6g of polyethylene glycol as a modifier. The mass ratio of the modifier to the magnetic nanoparticles is 0.1:1. After mixing evenly, sonicate at 30℃ for 30 minutes, and then separate the solid by magnetic adsorption. This solid is denoted as product 1.

[0136] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles A8.

[0137] Example 9

[0138] Referring to Example 1, the difference is:

[0139] S1: Take 6g of Fe3O4 magnetic nanoparticles and disperse them in 60mL of deionized water containing 6g of sodium hexadecylbenzenesulfonate as a modifier. The mass ratio of the modifier to the magnetic nanoparticles is 1:1.

[0140] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles A9.

[0141] Example 10

[0142] Referring to Example 1, the difference is:

[0143] S2: Add product 1 to 50g of deionized water, then add 20g of aniline, 2g of hydrochloric acid, and 2g of ammonium persulfate sequentially, and shake for 5 minutes to mix evenly. The mass ratios of magnetic nanoparticles to aniline are 0.3:1, acid dopant to aniline are 0.1:1, and initiator to aniline are 0.1:1.

[0144] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles A10.

[0145] Example 11

[0146] S2. Add product 1 to 50g of deionized water, then add 5g of o-phenylenediamine, 0.5g of citric acid, and 1g of ammonium persulfate sequentially. The mass ratios of magnetic nanoparticles to o-phenylenediamine are 1.2:1, the acid dopant to o-phenylenediamine is 0.1:1, and the initiator to o-phenylenediamine is 0.2:1.

[0147] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles A11.

[0148] Example 12

[0149] S1. Following step S1 of Example 1, except that the amount of the modifier polyethylene glycol is 3.2g and the mass ratio of the modifier to the magnetic nanoparticles is 0.8:1.

[0150] S2. Add product 1 to 50g of deionized water, then add 5g of o-phenylenediamine, 2g of hydrochloric acid, and 1g of ammonium persulfate sequentially. The mass ratios of magnetic nanoparticles to o-phenylenediamine are 0.8:1, the mass ratio of acid dopant to o-phenylenediamine is 0.4:1, and the mass ratio of initiator to o-phenylenediamine is 0.2:1.

[0151] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles A12.

[0152] Comparative Example 1

[0153] Referring to Example 1, the difference is that the modifier polyethylene glycol was not added in step S1.

[0154] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles D1.

[0155] Comparative Example 2

[0156] Referring to Example 1, the difference is that hydrochloric acid, an acid dopant, was not added in step S2.

[0157] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles D2.

[0158] Comparative Example 3

[0159] Referring to Example 1, the difference lies in step S1: 6g of Fe3O4 magnetic nanoparticles are dispersed in 60mL of deionized water containing 4g of polyvinylpyrrolidone.

[0160] The remaining steps are the same as in Example 1, to obtain functionalized magnetic nanoparticles D3.

[0161] The content of nitrogen, shell thickness, BET, and particle size of the functionalized magnetic nanoparticles prepared in the examples and comparative examples were tested, and the results are shown in Table 1.

[0162] Table 1

[0163]

[0164]

[0165] As shown in Table 1, in the embodiments of the present invention, treating the surface of magnetic nanoparticles with a modifier can effectively promote the polymerization of aromatic amine monomers on the surface of magnetic nanoparticles, resulting in a thicker shell and increasing the specific surface area of ​​the product. Adding a certain amount of acid dopant during the polymerization of aromatic amine monomers can increase the protonation degree of the polymer backbone, reduce the electron cloud density in the polymer molecular chain, and promote oxidative polymerization. Due to the doping effect, the delocalization of charge in the molecular chain increases, effectively improving electron transfer and transport, thereby increasing the adsorption capacity for heavy metal ions.

[0166] Test case

[0167] Heavy metal ion adsorption experiment

[0168] An aqueous solution containing four heavy metal ions—lead, cadmium, mercury, and chromium—was prepared in advance, with each ion having a concentration of 30 ppm.

[0169] 50 mg of functionalized magnetic nanoparticles A1-A12 and D1-D3 from Examples 1-12 and Comparative Examples 1-3 were taken sequentially and added to 6 mL of aqueous solutions containing lead, cadmium, mercury, and chromium ions, respectively. After 2 hours, 0.5 mL of the liquid was taken, and the concentration of heavy metal ions in the solution was measured by inductively coupled plasma atomic absorption spectrometry. The adsorption rate, % = (ion concentration before adsorption - ion concentration after adsorption) / ion concentration before adsorption × 100%.

[0170] Table 2

[0171]

[0172] Table 2 (continued)

[0173]

[0174] Table 2 (continued)

[0175]

[0176] Table 2 (continued)

[0177]

[0178] As shown in Table 2, the embodiments of this invention employ a modifier to treat the surface of magnetic nanoparticles, which can regulate the surface charge environment of the magnetic nanoparticles and promote the oxidative polymerization of aromatic amine monomers on their surface. Adding an acid dopant during the polymerization of aromatic amine monomers adjusts the protonation degree of the polymer backbone, improves electron transport capability, and the product exhibits significant adsorption effects on heavy metal ions such as lead, cadmium, copper, and chromium.

[0179] Figure 1This is a scanning electron microscope (SEM) image of the iron(Fe3O4) nanoparticles prepared in Example 1. Figure 2 The functionalized magnetic nanoparticles A2 prepared in Example 2 are derived from... Figure 1 and Figure 2 It can be seen that the surface of the unfunctionalized nanoparticles is smooth, while the surface of the functionalized nanoparticle A2 has a layer of polymer attached, which significantly increases its specific surface area.

[0180] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A functionalized nanoparticle, characterized in that, The functionalized magnetic nanoparticles have a core-shell structure, wherein the shell is an aromatic amine polymer and the core is a nanoparticle; The mass percentage of nitrogen (N) is 2-20 wt%, based on the total weight of the functionalized nanoparticles.

2. The functionalized nanoparticles according to claim 1, wherein, Based on the total weight of the functionalized nanoparticles, the mass percentage of nitrogen is 4-16 wt%.

3. The functionalized nanoparticles according to claim 1 or 2, wherein, The specific surface area of ​​the functionalized nanoparticles is 40-200 m². 2 / g, preferably 60-160m 2 / g; Preferably, the average particle size of the functionalized nanoparticles is 50-300 nm, and more preferably 60-230 nm; Preferably, the average thickness of the shell is 10-100 nm, and more preferably 20-80 nm.

4. The functionalized nanoparticles according to any one of claims 1-3, wherein, The aromatic amine polymer is selected from at least one of polyaniline, poly(o-phenylene diamine), poly(m-phenylene diamine), and poly(p-phenylene diamine); Preferably, the nanoparticles are selected from at least one of iron(II,III) oxide, cobalt(II), iron(II) oxide, and manganese(II) oxide; Preferably, the average particle size of the nanoparticles is 40-200 nm.

5. A method for preparing functionalized nanoparticles, characterized in that, The preparation method includes the following steps: S1. The nanoparticles are first mixed with a solution containing a modifier to obtain mixture I; S2. After mixing mixture I, aromatic amine monomer, initiator and acid dopant in a second mixture, a polymerization reaction is carried out to obtain mixture II; S3. After washing and drying mixture II, the functionalized nanoparticles are obtained; The modifier is selected from at least one of polyethylene glycol, sodium hexadecylbenzenesulfonate, sodium dodecyl sulfate, and sodium lignosulfonate.

6. The preparation method according to claim 5, wherein, The mass ratio of the modifier to the nanoparticles is 0.1-1:1, preferably 0.3-0.8:

1.

7. The preparation method according to claim 5 or 6, wherein, The mass ratio of the nanoparticles to the aromatic amine monomer is 0.2-3:1, preferably 0.8-2:

1.

8. The preparation method according to any one of claims 5-7, wherein, The aromatic amine monomer is selected from at least one of aniline, o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine; Preferably, the mass ratio of the acid dopant to the aromatic amine monomer is 0.05-0.5:1, more preferably 0.1-0.5:1; Preferably, the acid dopant is selected from at least one of citric acid, acetic acid, phosphoric acid, and sulfuric acid; Preferably, the mass ratio of the initiator to the aromatic amine monomer is 0.05-0.5:1, more preferably 0.1-0.3:1; Preferably, the initiator is selected from peroxide initiators, and more preferably from at least one of ammonium persulfate, potassium persulfate, and hydrogen peroxide.

9. The preparation method according to any one of claims 5-8, wherein, The first mixing was performed under ultrasonic conditions; Preferably, the conditions for the first mixing include: mixing temperature 20-30℃, mixing time 5-20 minutes, and ultrasonic power 10-50W; Preferably, the polymerization reaction conditions include: a polymerization temperature of 10-30°C and a polymerization time of 1-4 hours; Preferably, in step S3, the drying is constant temperature vacuum drying or forced air drying.

10. A functionalized nanoparticle prepared by the preparation method according to any one of claims 5-9.

11. The application of the functionalized nanoparticles according to any one of claims 1-4 and 10 in the field of heavy metal ion adsorption.

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